NGC's 'Hitler's Stealth Fighter' premieres Sunday, June 28
Otis Willie PIO The American War Library
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{EXCERPT} Monsters and Critics.com, April MacIntyre During World War II, brothers Walter and Reimar Horten designed a prototype for a German stealth plane that, if completed, could have changed history as we...
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Keith Willshaw
"Otis Willie PIO The American War Library" <themilit...@pacbell.net>
wrote in message news:qfmi45tea0bl0gu61...@4ax.com...
> NGC's 'Hitler's Stealth Fighter' premieres Sunday, June 28
> http://www.monstersandcritics.com/smallscreen/news/article_1486306.php/NGCs_Hitlers_Stealth_Fighter_premieres_Sunday_June_28
>
> {EXCERPT} Monsters and Critics.com, April MacIntyre During World War II,
> brothers Walter and Reimar Horten designed a prototype for a German
> stealth plane that, if completed, could have changed history as we...
>
>
I do wish somebody would take a clue stick to the tv producers who dish up
this rubbish
Making aircraft of wood does NOT make an aircraft stealthy. The large
rotating masses in the engines of the proposed Horten aircraft would
have given them a massive radar signature.
Keith
Malcom "Mal" Reynolds
<qZi2m.10511$Cq3....@newsfe04.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
Not according to the testing they did
Gordon
bug...@invalid.invalid> wrote:
>
> > I do wish somebody would take a clue stick to the tv producers who dish up
> > this rubbish
>
> > Making aircraft of wood does NOT make an aircraft stealthy. The large
> > rotating masses in the engines of the proposed Horten aircraft would
> > have given them a massive radar signature.
>
> Not according to the testing they did
I had to answer questions about this all day, while we completed the
display of this particular aircraft at our museum with hundreds of
visitors passing by.
Of course this _model_ of the Horten didn't have a massive radar
signal - you are aware it doesn't have any engines, and only single
substantial metal part (the mounting ring) right? I think the show
was patently ludicrous for more reasons than I care to type. But,
lets cover the first thirty seconds of the show, shall we?
First scene - American troops rumble through a forest toward the
mystical Stealth monster's lair. FACT: the aircraft was found at the
Gotha Waffenfabrik, a large industrial complex.
The American troops find a BARN in the middle of the woods - FACT:
the incomplete Ho 229 V-3 was found in a hangar.
As the doors open, the surprised American troops discover the
completed aircraft. FACT: it was only the center section, not
complete as shown in the TV show. The wings at the Smithsonian right
now, displayed with the center section, has not even been proven to
FIT the center section - and were found many miles away at a different
facility. Folks at the NASM decided instead of trying to fit the
three pieces together, they'd build a box for the wings and display
them alongside the center section. If they fit, they'd have
reassembled them prior to displaying the aircraft. That's what they
do, if they have all the right parts. That is what they are going to
ultimately do with their 219, and what they do with everything else
they have. The Horten is an anomaly, due to its questionable
connection to the wings.
Guys, these three errors occurred within -thirty seconds- of the start
of the show. From there, the accuracy of the show went down
markedly. That you were fooled is not surprising, as the producers
went out of their way to mislead the audience into thinking the Nazis
were actively and purposefully building a "Stealth fighter" in 1944.
Other canards: A 1v1 between the test aircraft and an Me 262, which
it supposedly won handlily? IT IS TO LAUGH. Quick question, did the
US (or anyone else) ever have a radical and unproven prototype
aircraft that was flown successfully once, and on its second flight it
was sent up to spar with an operational jet fighter? If you know of
any, please include a cite. What we KNOW from the historical record
and original source documents is that the second prototype crashed and
killed the pilot on it's second flight due to controllability issues.
Sure you want to dogfight in it before you even know how to fly it?
The show's producers made this ridiculous claim without a single sheet
of German wartime paper to back it up. No pilots named OF COURSE; no
logbook entries or other shred of proof. On the interwebs, we respond
to things like this with "Cool story, bro!"
Another one that made me want to spit was the complete fabrication
that Goering had _any_ input in its design. Other than his edict that
all new designs had to be capable of 3x1000, he played no role of any
kind. Yet, the show has him pacing his office, apparently deep in
contemplation on how to get the plywood and soft metal 540 mph
aircraft into production as the show weaves him into their inflated
BS. I kept waiting for the 'proof' that the Horten led to crop
circles and cow mutilations.
Please... "...the testing they did..." only proved the model was
somewhat stealthy, nothing else. The Horten MAY have had a lower RCS
than other aircraft of the day - but it would have been an unintended
consequence, not a result of a dedicated effort. I can explain,
hopefully: If I want to make a beautiful car, I am not going to make
a slab-sided moving van, I am going to smooth the fenders, round the
hull, and blend the parts into something akin to an Aston Martin.
Now, as a side-effect to those efforts, its likely going to be faster
than a moving van with the same engine, right? Ok, now, does that
mean I purposely built the car to be streamlined and faster than the
moving van, or were my efforts to make it beautiful rewarded with the
unintended consequence of allowing it to move with less resistance to
air? Same thing with the Horten - to make it faster, they blended the
wings into the fuselage - which, OBTW, helps with stealthy
properties. With its large wing control surfaces, an eppenage was not
needed; coincidentally, that meant it had no vertical surfaces to
reflect radar energy. So parts of its design, intended to help it
reach its targeted speed of 1000kph, also would have likely reduced
the RCS somewhat.
Now, a question for you - lets say you were building a 3x1000 aircraft
in 1944-45. You have an aircraft that is going to be streaking
through the sky at 1000kph, with NOTHING on the Allied side fast
enough to intercept you. Nothing. So, since you will be immune to
interception, who are you hiding from, why are you worrying about
stealth? Shit, you'd own the skies! The same situation that the
SR-71 caused would be in effect: as the fastest plane in the night
sky, even when the ground stations discovered the inbound raider, do
the math on what it would take to run an intercept with a 1944-1945
nightfighter, and tell me who the Horten would be hiding from? A
Mosquito..? The only danger they would generate would be from
collisions.
I love having the model, but that tv show was epically flawed. A pox
upon them that spun that web of lies.
Gordon
Rob
bug...@invalid.invalid> wrote:
> In article
> <qZi2m.10511$Cq3.10...@newsfe04.ams2>,
> �"Keith Willshaw"
> �<ke...@nospam.kwillshaw.demon.co.uk>
>
>
>
>
>
> �wrote:
> > "Otis Willie PIO The American War Library" <themilitaryto...@pacbell.net>
> > wrote in messagenews:qfmi45tea0bl0gu61...@4ax.com...
> > > NGC's 'Hitler's Stealth Fighter' premieres Sunday, June 28
> > > Hitlers_Stealth_Fighter_premieres_Sunday_June_28
>
> > > {EXCERPT} Monsters and Critics.com, April MacIntyre During World War II,
> > > brothers Walter and Reimar Horten designed a prototype for a German
> > > stealth plane that, if completed, could have changed history as we...
>
> > I do wish somebody would take a clue stick to the tv producers who dish up
> > this rubbish
>
> > Making aircraft of wood does NOT make an aircraft stealthy. The large
> > rotating masses in the engines of the proposed Horten aircraft would
> > have given them a massive radar signature.
>
> > Keith
>
>
> - Show quoted text -
The testing though was based on WW2 type radars and at that time just
the flying wing configuaration was stealthy enough. But the Ho-IX and
the intended Go-229 production a/c were to be made largely of non-
strategic wood impregnated with an anti-radar filler and later covered
in radar scattering materials, some of which were tested at
Messerschmitt's Oberammergau secret facility, along with the stop-
motor devices, variable-sweep wing Me P.1101, MK-213 revolver cannon,
and other top secret German a/c weapon systems.
Other anti-radar devices and materials were being tested at facilities
in Lofer, Austria where Sanger & Bredt were as well as Dr. Zippermeyer
(he was building his own Pfeil a/c and they were working on the
Silbervogel with a mock-up nearly completed).
The Germans certainly knew about stealth with the Kriegsmarine use of
Tarnmatte and Opanol on their Type XXI and Type XXIII U-boats and
their schnorkels.
While the Ho-IX was not dedicated stealth it certainly was work
pioneered in the right direction and worked against WW2 radars.
Facility documents were captured... but of course I have already
posted in that before and was just ignored.
But Keith cannot really comment that harshly about German stealth when
Britain had no equivalent at all for their subs or a/c. At least the
US tried dazzle camouflage and Project Yehudi light maniopulation
stealth techniques.
Rob
150flivver
reduction in radar cross section compared to similarly sized
conventional aircraft. While significant, it was hardly stealth. I
too found the part concerning it's superiority to the ME-262
ludicrous.
Dan
<snip>
>
> But Keith cannot really comment that harshly about German stealth when
> Britain had no equivalent at all for their subs or a/c.
The Brits didn't need it. They spent their money elsewhere. In case
you hadn't noticed the Nazis lost utterly.
Dan, U.S. Air Force, retired
Paul A. Suhler
any particular frequencies?
Paul
Keith Willshaw
"Rob" <teut...@aol.com> wrote in message
news:6ab7a20c-436c-4c25...@n21g2000vba.googlegroups.com...
On Jun 30, 1:46?am, "Malcom \"Mal\" Reynolds" <atlas-
>
> > Making aircraft of wood does NOT make an aircraft stealthy. The large
> > rotating masses in the engines of the proposed Horten aircraft would
> > have given them a massive radar signature.
>
> > Keith
>
> Not according to the testing they did- Hide quoted text -
>
> - Show quoted text -
> The testing though was based on WW2 type radars and at that time just
> the flying wing configuaration was stealthy enough. But the Ho-IX and
> the intended Go-229 production a/c were to be made largely of non-
> strategic wood impregnated with an anti-radar filler and later covered
> in radar scattering materials,
Thats a lot of unsupported assertions but even if ALL of them are true
would not alter the fact that the engines alone would have a massive
radar signature.
Keith
Keith Willshaw
"Dan" <B24...@aol.com> wrote in message
news:ZPm2m.6993$6A3....@newsfe20.iad...
The RAF and RN had no probblem finding German aircraft and submarines
on radar as their loss rates in 1944 and 1945 clearly show.
Keith
vaughn
"Keith Willshaw" <ke...@nospam.kwillshaw.demon.co.uk> wrote in message
news:ods2m.33901$6l1....@newsfe06.ams2...
> Thats a lot of unsupported assertions but even if ALL of them are true
> would not alter the fact that the engines alone would have a massive
> radar signature.
Perhaps, perhaps not. Directly from the front and rear it would be hard
to disagree, but otherwise it would depend on the angle and on how the radar
signal was affected (absorbed, reflected, deflected) by the aircraft
structure.
Vaughn
Ken S. Tucker
wrote:
I've read accounts claiming the DH Mosquito was invisible
to Nazi radar, but heres a link that supports Keith,
(you might try this link),
http://books.google.com/books?id=qZlrReU-cMkC&pg=PT42&lpg=PT42&dq=mosquito+bomber+%2B+radar+stealth&source=bl&ots=Nr7-fN09Uh&sig=hKjeQE3R8Umc1dkzq-JHyAPBwgY&hl=en&ei=SV1KSoCZMpKzlAewpPzUBg&sa=X&oi=book_result&ct=result&resnum=4
A lot depends on the radar frequency and power, and
then on the payload.
That said I think the 'truth' is classified, even from WW2,
though I figure the best "stealth" a/c of WW2 is the Mossie
by far.
The allies would certainly have noticed the Mossie's low
signature and would also have worked to reduce it, in the
variants of the 7,781 Nazi killers produced.
Ken
Gordon
> On Jun 30, 11:28 am, "vaughn" <vaughnsimonHATESS...@att.FAKE.net>
> wrote:
>
> > "Keith Willshaw" <ke...@nospam.kwillshaw.demon.co.uk> wrote in message
>
> >news:ods2m.33901$6l1....@newsfe06.ams2...
>
> > > Thats a lot of unsupported assertions but even if ALL of them are true
> > > would not alter the fact that the engines alone would have a massive
> > > radar signature.
>
> > Perhaps, perhaps not. Directly from the front and rear it would be hard
> > to disagree, but otherwise it would depend on the angle and on how the radar
> > signal was affected (absorbed, reflected, deflected) by the aircraft
> > structure.
> > Vaughn
>
> I've read accounts claiming the DH Mosquito was invisible
> to Nazi radar,
I would discount them as being unsupportable by direct evidence.
P-61s, other Mosquitos, even a Beaufighter NF all managed to find and
errantly attack Mosquitos operating over Northern Europe. Rare, yes,
but not unheard-of. In a couple of cases, Mossies were misclassified
as e/a and tracked from ground radar which vectored Allied
nightfigthers to a position to detect the bandits with their own on-
board radars.
Although their loss rate was low in comparison to everything else from
its time frame, there were losses to radar-directed German guns of
course. I've asked the question directly to flak gunners,
nightfighter pilots on both sides, and Mosquito guys (I was a long-
time member of the Mosquito Aircrew Association with a deep interest
in this subject), and all agreed it was not "invisible" or stealthy in
the modern sense, but its speed allowed it to make interception
windows both difficult and small.
> but heres a link that supports Keith,
> (you might try this link),http://books.google.com/books?id=qZlrReU-cMkC&pg=PT42&lpg=PT42&dq=mos...
>
> A lot depends on the radar frequency and power, and
> then on the payload.
> That said I think the 'truth' is classified, even from WW2,
> though I figure the best "stealth" a/c of WW2 is the Mossie
> by far.
Two big Merlins with attached props, perhaps a cookie or better yet,
some good old iron five hundred pounders are going to make it
observable on radar, but I agree its signature was probably
significantly lower that similarly-sized aircraft. Like I said, there
were interceptions, so its low viz didn't give it a cloak of
immunity.
> The allies would certainly have noticed the Mossie's low
> signature and would also have worked to reduce it, in the
> variants of the 7,781 Nazi killers produced.
I don't think so, Ken - the Mosquitos as built were superlative at
their assigned tasks and it was probably more important to churn out
more of them quickly as opposed to trying to make them dedicated
stealth platforms. Remember they were used to terrorize as much as
they were to bomb; it served a cruel purpose for the Mosquitos to be
heard, droning over some German city with scant ability to fend it
off. We didn't want or need a vengeance weapon like the V-2, arriving
from the heavens like the hammer of Thor without warning - what we
wanted was a reminder to the German citizenry that the RAF bombers
that could range far and wide, while delivering a devastating blow.
Why 'fix' that to make it stealthier?
v/r Gordon
Keith Willshaw
"Juergen Nieveler" <juergen.nie...@arcor.de> wrote in message
news:Xns9C3ADF80A6A1...@nieveler.org...
> "Ken S. Tucker" <dyna...@vianet.on.ca> wrote:
>
>> That said I think the 'truth' is classified, even from WW2,
>> though I figure the best "stealth" a/c of WW2 is the Mossie
>> by far.
>
>
> The best stealth planes were the gliders - the DFS230 and Horsa.
>
> Without metal engines, there's even less radar reflection than for the
> Mossie - unless the tin cans on the soldiers' heads could be detected
> ;-)
Actually they could. In Glide Path, the book by Arthur C Clarke about his
work on landing approach radar during WW2 he mentions the fact
that the radar could pick out sentries on duty around the airfield
Keith
Matt
same way they beat other German jet and rocket planes - using the
numbers and range of their fighters, especially the P-51, to shut down
its airfields and ambush it on takeoff and landing. But it was one
heck of an impressive technological advance, and it would have driven
the Allies to distraction for a while.
Matt Bille
Ian B MacLure
85e534...@33g2000vbe.googlegroups.com:
Howdya know it isn't accurate?
IBM
Ian B MacLure
news:8c7da594-4485-4b6d...@h8g2000yqm.googlegroups.com:
> On Jun 30, 3:46�am, "Malcom \"Mal\" Reynolds" <atlas-
> bug...@invalid.invalid> wrote:
>
>>
>> > I do wish somebody would take a clue stick to the tv producers who
>> > dish
> up
>> > this rubbish
>>
>> > Making aircraft of wood does NOT make an aircraft stealthy. The
>> > large rotating masses in the engines of the proposed Horten
>> > aircraft would have given them a massive radar signature.
>>
>> Not according to the testing they did
>
> I had to answer questions about this all day, while we completed the
> display of this particular aircraft at our museum with hundreds of
> visitors passing by.
>
> Of course this _model_ of the Horten didn't have a massive radar
> signal - you are aware it doesn't have any engines, and only single
> substantial metal part (the mounting ring) right? I think the show
> was patently ludicrous for more reasons than I care to type. But,
> lets cover the first thirty seconds of the show, shall we?
There don't have to be large pieces of metal only something
that reflects like metal and that is AIUI largely a function
of surface conductivity. Which you will notice was carefully
tailored. The NG model shop knows about that sort of thing
believe or not.
> First scene - American troops rumble through a forest toward the
> mystical Stealth monster's lair. FACT: the aircraft was found at the
> Gotha Waffenfabrik, a large industrial complex.
Nah that was a barn in Inyokern.
> Now, a question for you - lets say you were building a 3x1000 aircraft
> in 1944-45. You have an aircraft that is going to be streaking
> through the sky at 1000kph, with NOTHING on the Allied side fast
> enough to intercept you. Nothing. So, since you will be immune to
> interception, who are you hiding from, why are you worrying about
> stealth? Shit, you'd own the skies! The same situation that the
> SR-71 caused would be in effect: as the fastest plane in the night
> sky, even when the ground stations discovered the inbound raider, do
> the math on what it would take to run an intercept with a 1944-1945
> nightfighter, and tell me who the Horten would be hiding from? A
> Mosquito..? The only danger they would generate would be from
> collisions.
Radar controlled AAA and VT fuzes mayhap? Not to mention the
risk of being bounced whilst in the pattern.
IBM
Keith Willshaw
"Matt" <MattW...@AOL.com> wrote in message
news:fecde362-7770-4b14...@r34g2000vba.googlegroups.com...
Assuming
1) It flew at all
2) It's handling characteristics were suitable for squadron use
3) It didnt demonstrate fatal structural weaknesses
Recalling that the Horten Brothers were never to design a single
powered aircraft that entered service with the knowledge of
how many german aircraft programs failed and the record of
instability of early flying wing aircraft world wide that's a whole
lot of stuff to take for granted.
Then there is the little matter of the opposition. If by some miracle
the Red Army should lose its way on the road to Berlin and the
Luftwaffe can find a working airfield and trained pilot any Horten
flying wing is going to be meeting F-80's , DH Vampires and
Meteor IV's by the time it enters service
Keith
euno...@yahoo.com.au
> On Jun 30, 3:46 am, "Malcom \"Mal\" Reynolds" <atlas-
>
> bug...@invalid.invalid> wrote:
>
> > > I do wish somebody would take a clue stick to the tv producers who dish up
> > > this rubbish
>
> > > Making aircraft of wood does NOT make an aircraft stealthy. The large
> > > rotating masses in the engines of the proposed Horten aircraft would
> > > have given them a massive radar signature.
>
> > Not according to the testing they did
>
> I had to answer questions about this all day, while we completed the
> display of this particular aircraft at our museum with hundreds of
> visitors passing by.
>
> Of course this _model_ of the Horten didn't have a massive radar
> signal - you are aware it doesn't have any engines, and only single
> substantial metal part (the mounting ring) right?
The model had sheet metal tubes to simulate the exhaust. The internal
tube structure, undercarriage and engines were simulated using
conductive strips. (tapes). This is the way Northrop Grumman do it
in real life and they say it gives a good first order approximation
and they being the designers of the B2 Spirit know this from
experience.
SNIP
>
> The American troops find a BARN in the middle of the woods - FACT:
> the incomplete Ho 229 V-3 was found in a hangar.a
Yeah, TV is full of shit.
>
> As the doors open, the surprised American troops discover the
> completed aircraft. FACT: it was only the center section, not
> complete as shown in the TV show. The wings at the Smithsonian right
> now, displayed with the center section, has not even been proven to
> FIT the center section - and were found many miles away at a different
> facility.
The V1 flew as a glider, the V2 flew under jet power several times
when a combination of an asymetrical undercarriage opening and an
engine failure on the opposite side forced a landing short of the
runway into a ditch which rolled the aircraft and killed the pilot
Erwin Ziller.
The V3 wasn't completed as you pointed out.
Actual production Ho 229 were actually meant to be slightly larger and
to incorporate the special "formholz' ply contstuction. The 'formholz'
was a playwood with the filler being a mixture of sawdust, glue and
graphite which would have had some radar absorbing properties.
Graphite is the first 'nano' material which is why its used in typres
and platics.
>
> Guys, these three errors occurred within -thirty seconds- of the start
> of the show.
Dramaticisation, poetic liscence.
Doen't effect what the Northrop guys came up with.
From there, the accuracy of the show went down
> markedly. That you were fooled is not surprising, as the producers
> went out of their way to mislead the audience into thinking the Nazis
> were actively and purposefully building a "Stealth fighter" in 1944.
>
>What we KNOW from the historical record
> and original source documents is that the second prototype crashed and
> killed the pilot on it's second flight due to controllability issues.
Lost right engine and right undercarriage down while left up. To much
asymetry to handle. Pilot couldn't retract due to hydralic pump being
on faulty engine. Extension of undercarriage was by air bootle, this
failed to bring both legs down and caused the asymetry.
> Sure you want to dogfight in it before you even know how to fly it?
> The show's producers made this ridiculous claim without a single sheet
> of German wartime paper to back it up. No pilots named OF COURSE; no
> logbook entries or other shred of proof. On the interwebs, we respond
> to things like this with "Cool story, bro!"
>
> Another one that made me want to spit was the complete fabrication
> that Goering had _any_ input in its design. Other than his edict that
> all new designs had to be capable of 3x1000, he played no role of any
> kind. Yet, the show has him pacing his office, apparently deep in
> contemplation on how to get the plywood and soft metal 540 mph
> aircraft into production as the show weaves him into their inflated
> BS. I kept waiting for the 'proof' that the Horten led to crop
> circles and cow mutilations.
>
> Please... "...the testing they did..." only proved the model was
> somewhat stealthy, nothing else. The Horten MAY have had a lower RCS
> than other aircraft of the day - but it would have been an unintended
> consequence, not a result of a dedicated effort.
There have been a number of explanations as to why Rheimer and Werner
ended up building a stealh aircraft
1 Robert their brother was a Bf 109 pilot who lost his life during the
battle of britain.
2 Reimer was also a pilot and lost lots of friends.
3 They both wanted a way to get back and give their fellow German
pilots a superior aircraft.
4 Walter did speak of radar camaflage in Argentina in the 1950s
5 When using a Wurzburg FLAK radar which linked to a geraet 40 lampda
FLAK predictor to given them altitude speed and climb to test their
woode and plastic aircraft. (the actualy made a complete plastic
aircraft with plastic props) they noted the weak signal.
6 Walter was part of a think tank where he rubbed shoulders with
German Navy types who being aware that radar was being used against
them had done the logical thing and put their researchers to work on
the problem. They came up with several suiccesfull RAM materials.
All in all they were winging it on their own. The Germans infact
developed several very effective RAM materials. There was
Schonsteingfehger (chiney sweep) which was a ferrite based rubberised
coating applied to the snorkels of late war u-boats esp the Type XXI.
It cut down radar returns to only 5% and more or less made 3cm and
10cm radar useless in terms of detection range since the u-boats also
being issued Naxos like radar detectors. It was the 1950s before
multifrequency persicope detection radars restored some functionality
to anti periscope radars.
The other material was a Jaumann absorber which was highly effective
at a broad range of frequencies ranging from above 10cm down to well
below 3cm. The only problem was that it was 6cm thick and would have
thickened a 25cm snorkel to 37cm or so which is probably added to much
wake and visual signature.
Had the Hortens been seroous they might have brought in the
proffesionals and produced much better results unless secrecy concerns
ruled. The final wekaness was the radar reflections from the engine
inlets so coating the inlet sides, inlet shock cone and support spider
probably have cut RCS in half again.
> So parts of its design, intended to help it
> reach its targeted speed of 1000kph, also would have likely reduced
> the RCS somewhat.
The biggest single factor was the absence of propellors which make up
over half of an aircrafts radar returns.
A small single engined light plane has an RCS of 2m whereas a learjet
had only 1m and a T-38 Talon or F-5 have about 2. A jet has less than
half the RCS of a prop plane of the same size. The Ho 229 should have
had the signature of a Me 410 instead it had less than half that of a
Me 109.
The Ho 229 cut detection range by 20% compared to a Me 109 which means
that according to the radar equation its radar cross section is
0.8^0.25 or 40% that of the Me 109. A Mosquito due to its twin 4
bladed metal propellors would have had a RCS of about twice that of
the Me 109.
If an Me 109 had a RCS of 1m, a Ho 229 would be 0.4 and a Me 410 would
be 2-3 while a Mosquito would be about the same 2. Metal engines,
metal tube framing, metal undercarrage, metal control rigging running
throgh the wing, metal fuel tank running through the wing spar as a
reinforcement, metal tail wheel etc. The small amount for Graphite in
the Ho 229 would have absorbed some of the radar before it scattered
on the inner structure.
>
> Now, a question for you - lets say you were building a 3x1000 aircraft
> in 1944-45. You have an aircraft that is going to be streaking
> through the sky at 1000kph, with NOTHING on the Allied side fast
> enough to intercept you. Nothing. So, since you will be immune to
> interception, who are you hiding from, why are you worrying about
> stealth? Shit, you'd own the skies!
The Northrop guys found that it cut detection range by 20% which was
80 miles for a Me 109 against Chain Home Low. At 600mph (10 miles a
minute) detection time is reduced from about 8 minutes to 6 minutes,
The Metor I was hopless and the Meteor III even with derwents and the
extended nacels was no good either. It could do 480mph (derated from
495mph due to engine issues) however by the end of 1945 the Brits had
worked out tha they needed to extended the nacells even further to
reduce what must have been shock drag and they started getting to
600mph with guns removed and uprated engines in the Meteor IV. The
Mach limit of the Meteor was about Mach 0.8 so its was actually not
faster at high altitude than the Me 262 since the Mach limit of the Me
262 was Mach 0.86 This is because the Meteors dragged rose rapidly.
The Metor does become a threat by the end of 1945 but it is unlikely
and it can probably at best manage a single pass curling down into a
rolling dive as would be used against a V1
The same situation that the
> SR-71 caused would be in effect: as the fastest plane in the night
> sky, even when the ground stations discovered the inbound raider, do
> the math on what it would take to run an intercept with a 1944-1945
> nightfighter, and tell me who the Horten would be hiding from? A
> Mosquito..? The only danger they would generate would be from
> collisions.
>
> I love having the model, but that tv show was epically flawed. A pox
> upon them that spun that web of lies.
its not so bad technically:
Read this by one of the Northrop engineers involved:
http://www.secretprojects.co.uk/forum/index.php/topic,3583.msg59466.html
--------------------------------------------------------------------------------
I’m an advanced projects engineer/manager at Northrop Grumman
Aerospace Systems. I was the guy who introduced producer/director
Michael Jorgensen to the Northrop Grumman team and helped convince our
management to pursue and fund the Ho-229 documentary project. I’ve
been directly involved with this project from start to finish and I
appear in the show. I’d like to address some of the concerns you guys
have raised in this forum.
A number of you have expressed concern that the radar cross section
(RCS) testing of the constructed Ho-229 full-scale model is invalid
for various reasons, including that fact that the model does not have
an internal tubular truss structure, metallic engines, control
surfaces, etc. This assertion is simply not true. I’m assuming that
most of you are not low observables engineers, but please forgive me
if any of the following is tutorial.
At this point in time, the aerospace industry’s low observables (LO)
engineering community has considerable experience under its collective
belt. Over the decades, countless structures have been illuminated
across all possible radar frequency ranges. This includes full-up
aircraft and models, down to individual parts, representing all forms
of aircraft construction methods and material utilization developed
since the Wright Brothers. LO computational techniques have been
considerably refined and validated in comparison to empirical testing
results.
Before we started the build, we were able to inspect the actual Ho-229
in the Smithsonian Garber facility (an awesome experience!). We were
also able to do some testing of the actual aircraft’s surfaces to
determine their electromagnetic properties, which you’ll see in the
show. In addition, we had at our disposal a comprehensive package of
wonderful Ho-229 layout drawings prepared by Arthur Bentley, and Mr.
Bentley himself was a consultant to the project.
So, my point is that when we sat down to figure out how to build the
Ho-229 RCS test model, we already had an excellent detailed technical
understanding of this aircraft and how to effectively simulate it for
the purpose of determining its electromagnetic properties.
We discussed the possibility of reconstructing the truss structure,
but that would be cost prohibitive and our senior LO engineers
determined that it wasn’t really necessary. To obtain the kind of
first-order results we were looking for, it would be sufficient to
build the model from high-grade plywood with carefully targeted
applications of various conductive coatings internally and externally
to simulate the interior configuration. Specialized paints and
coatings are the key!! We have proven on various projects that this
technique works, and that’s the way we proceeded with the Ho-229.
Another key aspect in making the construction method decisions was
radar frequency. We studied the British Chain Home air defense radar
systems used throughout WW II. We concluded that the use of VHF, UHF
and L-band frequencies would be representative for our testing. At
these relatively low long-wavelength frequencies, small details on the
test model would not be visible or contribute significantly to the
overall signature, including the gaps in control surfaces. Also, the
coating methodology described above would be very effective at
accurately simulating this aircraft at these frequencies without the
need to recreate the interior features in detail. To keep things
simple, we tested the aircraft in a nominal straight and level flight
configuration, which would represent its best radar signature. It
would have been nice to include moveable control surfaces on the
model, but that was beyond the available budget.
Keep in mind that we built a test model for a one hour TV documentary,
not for developing and deploying a real combat aircraft! All we needed
in this case was enough engineering fidelity to achieve first order
results enabling us to reach some top-level conclusions. I believe our
project priorities were properly balanced with this goal in mind, and
of course, within the available budget.
As you all know, the Ho-229 was not designed with stealth as a primary
design goal. The aircraft has a few obvious stealth “Achilles’ Heels”
such as the exposed engine faces. However, a flying wing configuration
can nonetheless have inherently stealthy properties compared to
conventional aircraft even if LO was not a primary design
consideration. This was amply demonstrated by Northrop’s YB-49A.
Regarding the Ho-229’s RCS performance, we chose to not get into radar
signature reduction specifics in the documentary. Rather, we describe
the Ho-229’s capabilities in terms of the resulting reduction in
detection & warning time against the Chain Home radar system.
I agree that the show’s title “Hitler’s Stealth Fighter” is somewhat
misleading and was certainly not my first choice. The show was
produced under a different working title, but the Nat Geo Channel had
the final say. Bear in mind that a show like this is created for the
general public, not specifically for aviation enthusiasts. Nat Geo is
in business to stay in business and I can understand why they chose
this title. After more than half a century, anything “Hitler” still
sells. All that said, there’s plenty of good stuff in this documentary
and I think you guys will enjoy it.
As someone pointed out, the Nat Geo website for this show does state
that the Ho-229 RCS model was constructed using “materials only
available in the 1940’s”, and that is incorrect. They misinterpreted
our statements that we used materials that are, from the RCS
standpoint, representative of what was used in the 1940’s. I’ll see
what I can do to get that corrected.
By the way, the full scale Ho-229 RCS model is being donated to the
San Diego Air & Space Museum. We recently had a great meeting with the
museum’s team and we are making plans to get the model down there and
on display in time for the documentary’s debut.
All things considered, this has been a fun project. I appreciate
everyone’s interest and I hope you enjoy the show!
We specifically mention Chain Home in the show because of its great
historical significance and pivotal role in the early air war. Its
many variants were in service throughout the war performing the Early
Warning (EW) role. The only reason it wasn't being used much in 1945
other than V-2 detection was obviously because THERE WERE NO German
air assaults against the UK at that point. If there were, you can be
sure it would have been used extensively. Despite the existence of
more advanced individual radars at that point, the Chain Home Low and
other variants still constituted an entire integrated network,
essential to the adequate defense of the UK.
From a strategic standpoint, the most important aspect of the Ho-229's
radar signature is it's performance against EW radars, not Ground
Controlled Intercept (GCI) and Airborne Intercept (AI) radars. If the
Germans were hypothetically able to field the Ho-229 in significant
numbers and initiate offensive operations, The EW radar network is the
first line of defense and would have been used to cue the defensive
response to the attack. This is the reason we chose to test the Ho-229
against VHF, UHF, and L-Band, which covers the characteristic
operating frequencies for EW radars during this period of time. These
bands cover wavelengths from about 0.9 meters down to about 30 cm.
Of course, we would have loved to test the Ho-229 at higher
frequencies as well. We had neither the time nor the budget. I believe
that the percentage improvement in radar signature compared to
conventional aircraft would be approximately the same order of
magnitude at GCI and AI frequencies.
Keep in mind that we have a complex story to tell in about 42 minutes,
which is the length of the show without commercials (those of you in
Europe and Canada will get a 50 minute version!). We told the radar
story as best we could in the time available, in balance with the rest
of the story.
Also check out here.
http://www.defence.pk/forums/weapons-club/28898-hitlers-stealth-fighter-re-created.html
euno...@yahoo.com.au
> The program's testing concluded the aircraft had a 20 percent
> reduction in radar cross section compared to similarly sized
> conventional aircraft.
I'm in Australia so haven't seen the show yet. Hopefully I'll get the
50 minute pay TV low add version the Europeans will get. I believe
they found a 20% reduction in detection range compared to an Me 109
when tested against CHL. This is equivalent to a reduction in radar
cross section of 60%. IE if the Me 109 was 1m sq then the Ho 229
would be 0.4msq In reality the 1000kg x 1000km/h x 1000km (radious
not range) puts its lifting, range capabilities more than in the Me
410 and Mosquito class than the Me 109 class and compared to these
aircraft it must have a 5:1 reduction. A 20% reduction in RCS is not
realistic, it would have lost more than that simply becuase it is a
jet rather than a prop aircraft as props cause most of the
reflections.
They only tested against 10m (Chain Home) 1.5m (chain home low) and
50cm (UK army cgi) they didn't test against microwaves! They ran out
of money.
The production version of the Ho 229 was to be slightly larger with
different material than those parts captured by the US forces.
> While significant, it was hardly stealth.
I supect had it gotten into the air the low but still not low enough
radar return would have been noted and the application of the radar
absorbing materials develpoped for u-boat snorkels to the engine inlet
sides, inlet cones and support spider would have halved RCS again. In
stealth the devil is in the details.
> I too found the part concerning it's superiority to the ME-262
> ludicrous.
Drama is entertaining.
euno...@yahoo.com.au
> On Jun 30, 11:28 am, "vaughn" <vaughnsimonHATESS...@att.FAKE.net>
> wrote:
>
>
> I've read accounts claiming the DH Mosquito was invisible
> to Nazi radar, but heres a link that supports Keith,
> (you might try this link),http://books.google.com/books?id=qZlrReU-cMkC&pg=PT42&lpg=PT42&dq=mos...
If the Ho 229 production version had the formholz graphite/swadust
impregnated plywood then the graphite might both and absorb a little
and shield the innards of the aircraft.
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:b0d050bf-eda8-4211...@g19g2000yql.googlegroups.com...
>
>> Of course this _model_ of the Horten didn't have a massive radar
>> signal - you are aware it doesn't have any engines, and only single
>> substantial metal part (the mounting ring) right?
> The model had sheet metal tubes to simulate the exhaust. The internal
> tube structure, undercarriage and engines were simulated using
> conductive strips. (tapes). This is the way Northrop Grumman do it
> in real life and they say it gives a good first order approximation
> and they being the designers of the B2 Spirit know this from
> experience.
Lets get real here. Nobody who worked for Northrop Grumman
and worked on the B-2 is going to be talking about it on television.
This much I do know, you cant model the radar cross section
of a functioning engine using conductive tape
Keith
Ken S. Tucker
Well I think the usual thesis of giving the enemy the least
time to prepare for an attack stands. Also, the Mossie was
certainly an excellent hi altitude and hi speed photo-recon
platform, and it's best if the enemy doesn't know it's being
photographed.
http://www.diggerhistory.info/pages-air-support/ww2-allied/mosquito.htm
He's a blurb on Mosquito stealth,
http://www.associatedcontent.com/article/342056/the_first_stealth_fighter_the_de_havilland_pg2.html?cat=37
Ken
frank
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
Well, yeah, sort of maybe. A big part of stealth is how the shape
reflects RADAR. Which is why they built that RCS facility out in the
Mojave desert. I think the F-117 was the first thing that got tested
there.
Show was ok, some parts you could drive a truck through. Neat model
though.
What was interesting was.... they built a lot of models for other
designs. Which were subsequently scrapped. OK, so proof of concept?
New designs? Somebody getting smart and finally doing some funding of
aircraft that aren't at least a decade old in start of project?
Not to mention the facility where they test the design against
designed threats. Now, that wasn't done on a shoestring. Obviously
somebody wants stuff run through those tests.
Looks like we're doing some neat computer simulations stuff.
And yeah, those with bucks have better control rooms than those that
don't have bucks. And those with good control rooms keep the riff raff
out. Been there.
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
>
> news:b0d050bf-eda8-4211...@g19g2000yql.googlegroups.com...
>
>
>
> >> Of course this _model_ of the Horten didn't have a massive radar
> >> signal - you are aware it doesn't have any engines, and only single
> >> substantial metal part (the mounting ring) right?
> > The model had sheet metal tubes to simulate the exhaust. The internal
> > tube structure, undercarriage and engines were simulated using
> > conductive strips. (tapes). This is the way Northrop Grumman do it
> > in real life and they say it gives a good first order approximation
> > and they being the designers of the B2 Spirit know this from
> > experience.
>
> Lets get real here. Nobody who worked for Northrop Grumman
> and worked on the B-2 is going to be talking about it on television.
That's exactly what happened. Northrop Gruman used their experience,
stealth development facilities and people to help make this
'documentary' probably as public relations and to generate enthusiasm
for their products and capbillity for the American tax payer.
Stealth has been in the public eye for 20 years. You've been able to
buy several textbooks for at least 10 just on the topic of stealthy
aircraft desgin complete with photographs of the SR-71's internal
structure. Radar Absorbing technologies have been understood for 60
years (eg ferrite based absrobers, re-entrant structures, jaumann
absorbers, salsbury absrobers etc) and in anycase the principles are
plain electrical engineering and physics well stood and understood
from electromagnetic testing in emi anachoic chambers.
Reducing the RCS of an aircraft down to 0.1sqm even 0.01sqm is no
secret or magic. The Hortens in fact didn't even use a fraction of
what expertise and materials the Germans had developed mainly in
connection with submarine stealth. The Germans even had equipement
to measure RCS of aircraft and there are photographs of the
instruments and models used. They did this to improve and understand
radar not to develop stealth (except in the case of the makers of
steallthy materials for u-boats who clearly were measuring their
materials as well).
Getting RCS it down to the 0.001sqm to 0.0001sqm that Northrop Grumann
have for a massive bomber is however quite an achievment.
Its fairly obvious that that Northrop Grumann do not have to reveal
specific details of the formulation of their materials or their
structures. required to achieve RCS of under 0.001 in talking about
how to measure something around 0.4 to 0.1.
>
> This much I do know, you cant model the radar cross section
> of a functioning engine using conductive tape
You can get a first order approximation. Experience has shown that.
Realy its only realy that the first stage of the compressor and the
inlet duct that counts.
Typically of Americans they build a massive R+D faciltiy complete with
training and competency facilities to build a critical mass in
mastering the technology across a large number of people needed to
maintain and evolve existing systems as well as evolved more advanced
ones.
Keith Willshaw
"frank" <dhssres...@netscape.net> wrote in message
news:b8e17349-0658-4841...@j32g2000yqh.googlegroups.com...
>
> This much I do know, you cant model the radar cross section
> of a functioning engine using conductive tape
>
> Keith
> Well, yeah, sort of maybe. A big part of stealth is how the shape
> reflects RADAR. Which is why they built that RCS facility out in the
> Mojave desert. I think the F-117 was the first thing that got tested
> there.
And a big part of the RCS of an engine are the reflections of the
RADAR off the inlet ducting , which acts as a wave guide and
the spinning compressor blades which on a radar sparkles like
a Catherine wheel.
Keith
Ian B MacLure
[snip]
> This much I do know, you cant model the radar cross section
> of a functioning engine using conductive tape
And your LO engineering qualifications are what exactly?
IBM
Gordon
> "Keith Willshaw" <ke...@nospam.kwillshaw.demon.co.uk> wrote innews:HgN2m.5874$VX3....@newsfe14.ams2:
>
> [snip]
>
> > This much I do know, you cant model the radar cross section
> > of a functioning engine using conductive tape
>
> And your LO engineering qualifications are what exactly?
>
> IBM
Even the guys running the build, (tom somebody?) stated flatly that
"its obvious that stealth was not considered by the Horten
brothers" (paraphrasing, but accurate). Their wartime papers don't
mention anything about stealth at all.
The Northrop builders did not follow the wartime blueprints and built
little of the internal structure of the original aircraft - there is
only tubing in the cockpit section instead of the whole center
section; no electronics or fuel cells - its just an empty shell with
wooden trusses. Even the cockpit instruments are only paper and
bezels. The MASSIVE nose strut was not in place during the testing,
or the MLG which would also have been 'seen'. Also, it was only
tested against Chain Home frequencies and PRFs, not Centimetric AI
radars. The testing would not actually reveal much as far as the
original design, other than the obvious, that wood bounces back less
radar emissions than metal.
Gordon
euno...@yahoo.com.au
> On Jul 3, 1:43 am, Ian B MacLure <i...@svpal.org> wrote:
>
> > "Keith Willshaw" <ke...@nospam.kwillshaw.demon.co.uk> wrote innews:HgN2m.5874$VX3....@newsfe14.ams2:
>
> > [snip]
>
> > > This much I do know, you cant model the radar cross section
> > > of a functioning engine using conductive tape
>
> > And your LO engineering qualifications are what exactly?
>
> > IBM
>
> Even the guys running the build, (tom somebody?) stated flatly that
> "its obvious that stealth was not considered by the Horten
> brothers" (paraphrasing, but accurate). Their wartime papers don't
> mention anything about stealth at all.
Reimers 1950s paper delivered in Argentina mentions 'wood' as being
"Radar Camflauge". He doesn't specifically mention the charcoal in
that speech or paper that was publushed afterwards nor the advantages
of a flying wing in reducing RCS. But he does speak of the tactical
advantage of "Radar Camaflauge" so without a doubt he was thinking of
stealth.
You can read Reimers May 1952 Article in Spanish here:
http://www.twitt.org/Horten_May_50.html
" I want only to remark the visibility of the aircraft. In the past,
the detector was human eye, later it was the grounded radio that
provided guidance until the airplane met the enemy. Today the pilot
has the assurance of recognizing, even at night, an airplane flying
many kilometers far, by means of the radar. In the past, planes were
covered with camouflage paintings, and with the advent of radar, the
already considered antique wood constructions, turned into something
modern again. As reflection of electric waves on metallic surfaces is
good, such is the image on the radar screen; on the contrary, on wood
surfaces, that reflection is little, these resulting barely visible on
the radar. "
Somehow he was of the mind that the wooden construction would create
"Radar Camaflauge".
I've read that they became aware of the low radar cross section of the
wooden gliders and plastic aircraft which proably would have shown up
as discernably weaker blips on the A scope displays of a Wurzburg
radar. The radar opperators of such radars would have been acutely
sensitive to the size of a blip on the A scope as it would indicate
the size of a target,whether it was a Lancaster or Mosquito and simply
sifting it out of all of the window being droped would tend to develop
a good feel. Note also that the Horten Ho Va was made of plastics,
including the propellor.
>
> The Northrop builders did not follow the wartime blueprints and built
> little of the internal structure of the original aircraft -
One thing to note is that the Horton V2 and V3 prototypes used a
classic wood and plywood construction. The production versions were
supposed to use a special type of plywood which used as its core not
cross plys but plastic chip board wood called "formholze". The
insides of the fueselage were to be filled with fuel using special
glue to coat the wood. In other words the aircraft was to be a 'wet
wing' with an integral fueltank. If the test was to be accurate the
production version should be used and it should be filled with Jet
fuel. the special fuel resistant glue also crops up in relation to
the Ta 152H-1 and the He 162. It is my understanding that at least on
the Ta 152 that the wings were filled with massive bags ( It think 3 x
150L in each wing).
The formholze is a critical part of the entire matter because it was
laced with carbon black which is semiconductive and would thus absorb
radiowaves as well as shield the matalic inards of the aircraft.
Graphite is indeed used for this purpose. Carbon black/graphite/
charcoal is often used in platics for the same reason it is used in
tyres: it is a nano material and a reinforcement. Carbon fiber is
only a bigger form of it. So it can be argued that the presence of
the charcoal in the formholze was structural instead of intentional.
> there is
> only tubing in the cockpit section instead of the whole center
> section; no electronics or fuel cells - its just an empty shell with
> wooden trusses. Even the cockpit instruments are only paper and
> bezels. The MASSIVE nose strut was not in place during the testing,
> or the MLG which would also have been 'seen'. Also, it was only
> tested against Chain Home frequencies and PRFs, not Centimetric AI
> radars.
That's because they determined that the value in stealth would be
mainly in reducing early warning time and in the UK early warning air
defences of the time microwave radars were not used. I rather tend
to think that the Horten would have worked better at microave
frequencies only because stealth materials are generally more
effective at higher frequencies.
Stealth would be relatively useless against Chain Home but Chain Home
could be avoidedy by flying low, the radar to deal with low flying
aircraft was Chain Home Low and it was slightly degraded.
> The testing would not actually reveal much as far as the
> original design, other than the obvious, that wood bounces back less
> radar emissions than metal.
It doesn't take much to get a bounce back, wood itself will get a
deteactable rebounce back. German airborn 50cm "Hohtenweil" Radars
could find rubber liftrafts in the sea. A piece of aluminised mylar
or silver and gaphite laden paint is going to be as good as a steel
tube.
The other obvious thing here is that jet aircraft have 1/2 to 1/4 the
radar cross section of prop aircraft of the same size and weight even
with exposed engine inlets. In addtion the shape of the 'flying
wing' itself would have had less RCS than say and Me 262 or Meteor and
certainly say a Fw 190 or P-47 when viewed from the front.
A word here on the real German stealth materials.
There were two
http://www.cdvandt.org/CIOS%20XXVI-24.pdf
1 The Wesch Absorber.
2 The Jaumann Absorber.
The Wesch Absorber was a rubbersied ferrite ladden material tough
enough to withstand being wraped around mast and cap of a submarine
snorkerl. In that form it was about 7mm thick and absorbed 95% of
9cm radar waves and 90% of 3cm radar waves.
At 5cm it only aborbed 30% but that frequency wasn't used by the
Allies. (this ironically was the freuquency the Germans had targeted
in their aborted microwave program). It effectively halved detection
range of allied radar and forced them to search 4 times the area in
good weather. In bad weather it effectively made detection
impossible.
The Jaumann Absrober was multilayered material of 7 sheets each of
which had exponentianly increasing conductivities. It absorbed over
99% of radation at 3cm and 9cm and reduced detection range to 15% of
normal. (effectively 1km in good weather). The Jaumann Absrober was
6.5cm thick. About 5cm of this was the RAM the rest cladding. It
worked from a few mm to about 20cm.
I believe all German snorkels (first deployed in the lat month of
1944) were of the Wesch type though there were some of the Jaumann
type which was applied to the mast but not the cap.
Effectively using radar was going to help the u-boats since it would
anounce the aircraft prescence. It was a big lound "Hello, look at
me"
Had the Hortens develped a second generation Ho 229 then application
of either of these proper stealth materials (adapted to the weight
requirements of aircraft rather than the marine enironment),
especially around the inlets, would have produced a powerfull stealth
aircraft.
>
> Gordon
You can see the reasoning behined the condutive tapes here.
http://www.secretprojects.co.uk/forum/index.php/topic,3583.msg59466.html
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> "frank" <dhssresearc...@netscape.net> wrote in message
A bigger part of the RCS of an aircraft is the absence of prescence of
propellors which double to quadrouple the RCS of an aicraft.
If one replaced the metal props and merlin engines and the radiators
of a DH Mosquito with a pair of jet engines I expect the the RCS of
the aircraft to more than halve and one would have an aircraft with
about the same range-payload characteristic as the Ho 229 yet the Ho
229 would possibly still have a half the RCS of the Mosquito since the
lack of wing fueselage and engine corners as well as tail means there
is no radar trap on the flying wing and because the charcoal of the Ho
229 would absorb a bit of the radar before it scattered on the steel
trusses of the fueselage and engines.
Its true that the first stage compressors would still reflect radar
but out aircraft would still have a fraction of the RCS of a
conventional aircraft. It would appear to be tactically significant
in the sense of cutting down warning time by 20% (say 6-8 minutes
instead of 8-10) The proper solution would be to move the engines
outboard and hide the compressors via a s-bend, failing that lining
the intake duct and support spiders with RAM and using the intake cone
to both absore and deflect into the absorbant duct would probably
halve the intakes reflections.
>
> Keith
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:c296a1fa-9fd8-4dbb...@v23g2000pro.googlegroups.com...
On Jul 3, 4:54 pm, Gordon <Gor...@oldboldpilots.org> wrote:
>
>> Even the guys running the build, (tom somebody?) stated flatly that
>> "its obvious that stealth was not considered by the Horten
>> brothers" (paraphrasing, but accurate). Their wartime papers don't
>> mention anything about stealth at all.
> Reimers 1950s paper delivered in Argentina mentions 'wood' as being
> "Radar Camflauge".
Yet the DH Mosquito was clearly visible on German radars
> As reflection of electric waves on metallic surfaces is
> good, such is the image on the radar screen; on the contrary, on wood
> surfaces, that reflection is little, these resulting barely visible on
> the radar. "
The DH Vampire had a plywood construction too - does that
make it the worlds first stealthy jet ?
This is nonsense
Keith
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:9db002ea-4c92-414a...@d2g2000pra.googlegroups.com...
On Jul 2, 6:08 pm, "Keith Willshaw"
>>
>> And a big part of the RCS of an engine are the reflections of the
>> RADAR off the inlet ducting , which acts as a wave guide and
>> the spinning compressor blades which on a radar sparkles like
>> a Catherine wheel.
> A bigger part of the RCS of an aircraft is the absence of prescence of
> propellors which double to quadrouple the RCS of an aicraft.
Lets see some evidence for that claim please
> If one replaced the metal props and merlin engines and the radiators
> of a DH Mosquito with a pair of jet engines I expect the the RCS of
> the aircraft to more than halve and one would have an aircraft with
> about the same range-payload characteristic as the Ho 229 yet the Ho
> 229 would possibly still have a half the RCS of the Mosquito since the
> lack of wing fueselage and engine corners as well as tail means there
> is no radar trap on the flying wing and because the charcoal of the Ho
> 229 would absorb a bit of the radar before it scattered on the steel
> trusses of the fueselage and engines.
And your qualifications as a radar expert are what exactly ?
> Its true that the first stage compressors would still reflect radar
> but out aircraft would still have a fraction of the RCS of a
> conventional aircraft.
Another claim made without ANY facts to validate it
> It would appear to be tactically significant
> in the sense of cutting down warning time by 20% (say 6-8 minutes
> instead of 8-10) The proper solution would be to move the engines
> outboard and hide the compressors via a s-bend,
The problem is that first generation jets were notoriously
sensitive to jet intake design which is why they tended to be
podded to reduce the inleat and jet pipe lengths to a minimum
> failing that lining
> the intake duct and support spiders with RAM and using the intake cone
> to both absore and deflect into the absorbant duct would probably
> halve the intakes reflections.
And fatally exacerbate the engines already notorious tendency to suffer from
compressor stalls.
You also seem to have missed the little fact that RAM tend to be effective
against a limited frequency range which is why the Kriegsmarine were
happily assuming there RAM treated snorkels were invisible when in
fact the British centimetric radar could pick them up at 5 miles.
Reality is a bitch.
Keith
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
>
> news:9db002ea-4c92-414a...@d2g2000pra.googlegroups.com...
> On Jul 2, 6:08 pm, "Keith Willshaw"
>
>
>
> >> And a big part of the RCS of an engine are the reflections of the
> >> RADAR off the inlet ducting , which acts as a wave guide and
> >> the spinning compressor blades which on a radar sparkles like
> >> a Catherine wheel.
> > A bigger part of the RCS of an aircraft is the absence of prescence of
> > propellors which double to quadrouple the RCS of an aicraft.
>
> Lets see some evidence for that claim please
In fact with a high PRF radar it can increase it by 30 fold.
>
> > If one replaced the metal props and merlin engines and the radiators
> > of a DH Mosquito with a pair of jet engines I expect the the RCS of
> > the aircraft to more than halve and one would have an aircraft with
> > about the same range-payload characteristic as the Ho 229 yet the Ho
> > 229 would possibly still have a half the RCS of the Mosquito since the
> > lack of wing fueselage and engine corners as well as tail means there
> > is no radar trap on the flying wing and because the charcoal of the Ho
> > 229 would absorb a bit of the radar before it scattered on the steel
> > trusses of the fueselage and engines.
>
> And your qualifications as a radar expert are what exactly ?
That's Ad Hominem, smarmy at that.
You seem to think you have much of a clue. You don't at all which you
would realise if you had of gone a little deeper into things rather
than focus your energies at attacking my credentials, you bothered
to educate yourself otherwise you wouldn't ask somewhat inane
questions.
You can just google "radar cross section propellor" etc and you can
find tables comparing various aircraft types.
I found mine in an reference book thats been in my professional
library for 20 years which you can check oin google books and then
several more.
http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+propeller&as_brr=3
A Nimrod incidently has a significantly lower cross section than a
Orion, something which was emphaised when the aircraft was upgraded
from spey to BR715.
I'm a graduate electrical engineer, and though I work in the field of
autimation, I've had plenty of training in the field of radio wave
propagation in various media. A n electrical engineering degree puts
one throught years of hell in this area of studying impedence
matching, dielectric media, skin depth etc. There is nothing
magical about absorbing radar waves: its what antena and receiver
design is all about.
Textbooks on radar, even those not dealing with stealth, touch on RCS
and most particularly the effect of propellor modulations.
Even in WW2 the Germans used "Nurenburg" a device that listened
through window to given an audiable tone of an aircrafts propellors
to help the opperator reacquire a signal he might have lost. If
those prop frequencies were moudlated with an FM signal and displayed
on an x-y scope one would have the fourier spectrum which could be
matched to blade number and prop rpm to indentify aircraft type.
>
> > Its true that the first stage compressors would still reflect radar
> > but out aircraft would still have a fraction of the RCS of a
> > conventional aircraft.
>
> Another claim made without ANY facts to validate it
My claims are so transparently obvious and easy to verify I find it
mind boggling that i should need to verity them for you. If you were
some teenager I might have put in the effort to help, but your grown
up I think and I would've thought that you wouldn't have need such
basic help.
google RCS propellor
http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+propeller&as_brr=3
In fact if a prop blade changed 1/3 of a degree the RCS area of a B-26
could increase by a factor of 23!
http://books.google.com.au/books?id=qZlrReU-cMkC&pg=PT28&dq=radar+cross+section+propeller
>
> > It would appear to be tactically significant
> > in the sense of cutting down warning time by 20% (say 6-8 minutes
> > instead of 8-10) The proper solution would be to move the engines
> > outboard and hide the compressors via a s-bend,
>
> The problem is that first generation jets were notoriously
> sensitive to jet intake design which is why they tended to be
> podded to reduce the inleat and jet pipe lengths to a minimum
True though there was an over reaction in that area as duct losses
turned out to be less significant than expected, the primary reason
for podding was safety, it saved the lives of pilots to have them
podded since it stopped fire from spreading to the wing-tanks. The
second reason was structural and cost, one didn't need to forge go
around spars and one could keep the wing skins intact so that they
could be used as part of a torsion box.
>
> > failing that lining
> > the intake duct and support spiders with RAM and using the intake cone
> > to both absore and deflect into the absorbant duct would probably
> > halve the intakes reflections.
>
> And fatally exacerbate the engines already notorious tendency to suffer from
> compressor stalls.
Jumo's suffered from flameouts caused by poor poor fuel control and
poor atmoisation of the fuel.
Both problems has been solved by Feb 1945 and were to be delivered in
march/april. I can verifty that with Luftwaffe corresponence.
There was not a compressor stall problem, there was a surge problem at
high altitude and high speed that was dealt with by reducing engine
RPM a little (about 200 or so), this naturally caused a loss of power
and a reduction in airflow that started to make the fuel vapourisation
problem worse.
Duplex nozzles provided for vapurisation at low flow rates and the
'accelerator valve' would have fixed the problem of fuel starvation
from rapid throttle movement. The BMW 003 had the accelerator valve.
The Jumo 004D was to get all of the above and had a new compressors to
deal with these issues as well.
It wouldn't effect the intake at all since the physical geometry would
be uneffected: I'm assuming that the the inlet duct is not part of the
engine proper while the inlet cone is merely a metal cap. It would be
turned into a whitches had like cone and covered with a biconvex
curve.
>
> You also seem to have missed the little fact that RAM tend to be effective
> against a limited frequency range which is why the Kriegsmarine were
> happily assuming there RAM treated snorkels were invisible when in
> fact the British centimetric radar could pick them up at 5 miles.
There were two centrimetric radars, at 10cm and 3cm. Both were
greatly deteriorated by the basic RAM (Wesch) and rendered useless by
the advanced RAM (Jaumann).
It must also be pointed out that by Feb 1944 the Germans had radar
detectors for 10cm and 3cm ASV radar. The first experimental RAM clad
snorkel boats didn't however appear till October 1944.
A late war u-boat would have been delighted to have british patrol
aircraft anouncing their bearing and presecene with a nice big radar
signal. It greatly simplified their lookout task since they were more
vulnerable to visual detection at dawn or dusk than radar detection.
http://books.google.com.au/books?id=FW_50wm8VnMC&pg=PA38&dq=radar+type+XXI+snorkel&lr=&as_brr=3
"Fast Snorkel Boats Succh as the Type XXI were practivally impervious
to radar"
"Radar techniques succeded in hiding the snorkel"
You've fabricated all of that and its clearly nonsense. The
designers of the Kriegsmarines RAM coating took mearements and worked
out that the Wesch absorbers cut detection range in half.
It's rather dumb to think that men that can design such a coating
wouldn't take measurments to try and see how effective they were...
In fact they went further in testing the behaviour of the coating:
they subjected actual snorkels in submarines to their own Microwave
radars, the Berlin series which were mounted on Fw 200s. The thing to
note is that the Wesch Abssrobers were particulary effective at both
3cm and 9cm which is all that was needed since that is all that the
allies used. The weakeness was at 5cm a frequency the Allies didn't
use. The Jaumann absorbers, which were physically thicker, was
broadband and were 99% effrective from a few mm all the way to 20cm
with no week spots from 0mm to 10cm.
The reality however is that the covered snorkels rendered ASV radar
ineffective. Its fine to talk about picking up a snorkel in a flat
sea while it is fully proud of the water in a test when the radar
opperator knows there is a target there, quite another when the
snorkel is boobing in a slight chop. As it turns out 10cm radar was
well absorbed by the Wesch absorber while 3cm radar was absrobed only
a little less.
The reality was that in unsual circumstance, calm seas, snorkel and
antean all out a radar camafaluged snorkel might be picked up at 5
miles of so. On the same day a uncoated snorkel was detected at only
2.5 miles.
The Wesch absrobers killed of 95% at 10cm and 90% at 3cm. At 3cm
radar also pick up wave tops, porpoise and fish leaping, flotsame and
jetsam, whale spouts etc. 3cm marined radar is not trusted for this
reason.
The Jaumann absorbers, which were genrally fitted to few boats killed
of 99.5% of reflections and effectively cut detection range to 15%
which is to say about 1km, which is next to useless. A few type 23
seem to have gotten Jaumann types.
>
> Reality is a bitch.
Delusion is your bitch.
Incidently to this day anti submarine radar has not recovered its
abillity to detect snorkels, masthead stealth has evolved.
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
No, for two reasons:
1 the shape is not a flying wing and so there are more radar traps
2 there was apparently no use of graphite in the construction of the
plywood. the Jury is out on whether the Hortens 'knew' that the
graphite would have slightly improved RCS.
I would say that it would have had one of the lowest RCS since it
lacked propellors and the Goblin engine was well hidden alebeit within
metal ducts that would have acted as a waveguide.
>
> This is nonsense
>
> Keith
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:01431c37-12ea-4932...@i8g2000pro.googlegroups.com...
> On Jul 4, 2:56 am, "Keith Willshaw"
> <ke...@nospam.kwillshaw.demon.co.uk> wrote:
>> <eunome...@yahoo.com.au> wrote in message
>>
>> news:9db002ea-4c92-414a...@d2g2000pra.googlegroups.com...
>> On Jul 2, 6:08 pm, "Keith Willshaw"
>>
>>
>>
>> >> And a big part of the RCS of an engine are the reflections of the
>> >> RADAR off the inlet ducting , which acts as a wave guide and
>> >> the spinning compressor blades which on a radar sparkles like
>> >> a Catherine wheel.
>> > A bigger part of the RCS of an aircraft is the absence of prescence of
>> > propellors which double to quadrouple the RCS of an aicraft.
>>
>> Lets see some evidence for that claim please
>
> In fact with a high PRF radar it can increase it by 30 fold.
>
Thats an unsupported assertion - not evidence.
>>
>> > If one replaced the metal props and merlin engines and the radiators
>> > of a DH Mosquito with a pair of jet engines I expect the the RCS of
>> > the aircraft to more than halve and one would have an aircraft with
>> > about the same range-payload characteristic as the Ho 229 yet the Ho
>> > 229 would possibly still have a half the RCS of the Mosquito since the
>> > lack of wing fueselage and engine corners as well as tail means there
>> > is no radar trap on the flying wing and because the charcoal of the Ho
>> > 229 would absorb a bit of the radar before it scattered on the steel
>> > trusses of the fueselage and engines.
>>
>> And your qualifications as a radar expert are what exactly ?
>
>
> That's Ad Hominem, smarmy at that.
>
No its a question
You have been freely giving your opinion about the effects of various
configurations on RCS. It's reasonable to ask how well you are
qualified to make such assessments.
>
> You seem to think you have much of a clue. You don't at all which you
> would realise if you had of gone a little deeper into things rather
> than focus your energies at attacking my credentials, you bothered
> to educate yourself otherwise you wouldn't ask somewhat inane
> questions.
>
> You can just google "radar cross section propellor" etc and you can
> find tables comparing various aircraft types.
>
> I found mine in an reference book thats been in my professional
> library for 20 years which you can check oin google books and then
> several more.
> http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+propeller&as_brr=3
>
> A Nimrod incidently has a significantly lower cross section than a
> Orion, something which was emphaised when the aircraft was upgraded
> from spey to BR715.
>
>
Nobody claims the Nimrod is stealthy now do they ?
>
> I'm a graduate electrical engineer, and though I work in the field of
> autimation, I've had plenty of training in the field of radio wave
> propagation in various media. A n electrical engineering degree puts
> one throught years of hell in this area of studying impedence
> matching, dielectric media, skin depth etc. There is nothing
> magical about absorbing radar waves: its what antena and receiver
> design is all about.
>
Nobody has suggested sorcery was involved
> Textbooks on radar, even those not dealing with stealth, touch on RCS
> and most particularly the effect of propellor modulations.
> Even in WW2 the Germans used "Nurenburg" a device that listened
> through window to given an audiable tone of an aircrafts propellors
> to help the opperator reacquire a signal he might have lost. If
> those prop frequencies were moudlated with an FM signal and displayed
> on an x-y scope one would have the fourier spectrum which could be
> matched to blade number and prop rpm to indentify aircraft type.
>
>
Nurenburg
>
>
>
>
>>
>> > Its true that the first stage compressors would still reflect radar
>> > but out aircraft would still have a fraction of the RCS of a
>> > conventional aircraft.
>>
>> Another claim made without ANY facts to validate it
>
> My claims are so transparently obvious and easy to verify I find it
> mind boggling that i should need to verity them for you. If you were
> some teenager I might have put in the effort to help, but your grown
> up I think and I would've thought that you wouldn't have need such
> basic help.
>
> google RCS propellor
> http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+propeller&as_brr=3
>
A table of RCS of different classes of aircraft - interwsting but it hardly
proves your point
> In fact if a prop blade changed 1/3 of a degree the RCS area of a B-26
> could increase by a factor of 23!
>
> http://books.google.com.au/books?id=qZlrReU-cMkC&pg=PT28&dq=radar+cross+section+propeller
>
>
None of which address the issue of the RCS of a propellor compared with
those
of a turbo jet. Indeed this book deals extensively with the necessity to
screen the compressor which as it says reflects radar very effectively.
It also mentions that jet intakes form re-entrant structures that have a
very high RCS.
>
>
>>
>> > It would appear to be tactically significant
>> > in the sense of cutting down warning time by 20% (say 6-8 minutes
>> > instead of 8-10) The proper solution would be to move the engines
>> > outboard and hide the compressors via a s-bend,
>>
>> The problem is that first generation jets were notoriously
>> sensitive to jet intake design which is why they tended to be
>> podded to reduce the inleat and jet pipe lengths to a minimum
>
> True though there was an over reaction in that area as duct losses
> turned out to be less significant than expected, the primary reason
> for podding was safety, it saved the lives of pilots to have them
> podded since it stopped fire from spreading to the wing-tanks. The
> second reason was structural and cost, one didn't need to forge go
> around spars and one could keep the wing skins intact so that they
> could be used as part of a torsion box.
>
>
>
>>
>> > failing that lining
>> > the intake duct and support spiders with RAM and using the intake cone
>> > to both absore and deflect into the absorbant duct would probably
>> > halve the intakes reflections.
>>
>> And fatally exacerbate the engines already notorious tendency to suffer
>> from
>> compressor stalls.
>
> Jumo's suffered from flameouts caused by poor poor fuel control and
> poor atmoisation of the fuel.
>
Indeed they did
> Both problems has been solved by Feb 1945 and were to be delivered in
> march/april. I can verifty that with Luftwaffe corresponence.
>
Indeed but the compressor stall problem remained
> There was not a compressor stall problem, there was a surge problem at
> high altitude and high speed that was dealt with by reducing engine
> RPM a little (about 200 or so), this naturally caused a loss of power
> and a reduction in airflow that started to make the fuel vapourisation
> problem worse.
>
Sorry old boy but the Jumo did indeed suffer with compressor stall
particularly if the engine was throttled back too quickly. This is a
problem with all axial flow engines which is one of the reasons
Whittle picked the centrifugal compressor. To alleviate it Junkers fitted a
governor to regulate engine acceleration and decelleration but all
German pilots were well aware of the problem
see
Jagdgeschwader 7 'Nowotny'
By Robert Forsyth, Jim Laurier
> Duplex nozzles provided for vapurisation at low flow rates and the
> 'accelerator valve' would have fixed the problem of fuel starvation
> from rapid throttle movement. The BMW 003 had the accelerator valve.
> The Jumo 004D was to get all of the above and had a new compressors to
> deal with these issues as well.
>
> It wouldn't effect the intake at all since the physical geometry would
> be uneffected: I'm assuming that the the inlet duct is not part of the
> engine proper while the inlet cone is merely a metal cap. It would be
> turned into a whitches had like cone and covered with a biconvex
> curve.
>
More unsupported assertions.
>
>>
>> You also seem to have missed the little fact that RAM tend to be
>> effective
>> against a limited frequency range which is why the Kriegsmarine were
>> happily assuming there RAM treated snorkels were invisible when in
>> fact the British centimetric radar could pick them up at 5 miles.
>
> There were two centrimetric radars, at 10cm and 3cm. Both were
> greatly deteriorated by the basic RAM (Wesch) and rendered useless by
> the advanced RAM (Jaumann).
>
Which seems to have been fielded in a very small number of boats
if at all.
> It must also be pointed out that by Feb 1944 the Germans had radar
> detectors for 10cm and 3cm ASV radar. The first experimental RAM clad
> snorkel boats didn't however appear till October 1944.
>
Nope. They had Naxos which worked at 10cm but the 3cm detector was not
available until spring 1945 and less than 100 had been assembled
while the RAF had been using 3cm radar for over a year - oops
http://www.uboat.net/technical/detectors.htm
> A late war u-boat would have been delighted to have british patrol
> aircraft anouncing their bearing and presecene with a nice big radar
> signal. It greatly simplified their lookout task since they were more
> vulnerable to visual detection at dawn or dusk than radar detection.
>
German U-boat crews were less sanguine, not surprising given how many
were lost to airborne attack. It is no coincedence that the closing of the
air gap in the North Atlantic by radar equipped Liberators happened
in the run up to the crisis of the Battle of The Atlantic. From that point
on there was no period when it was safe to be on the surface. As for
snorkels thet are indeed useful but the North Atlantic is not conducive
to their use.
Take a look at the table of U-boat losses in 1943/4/5 and note how many
were to aircraft.
http://www.uboat.net/fates/losses/1943.htm
http://www.uboat.net/fates/losses/1944.htm
http://www.uboat.net/fates/losses/1945.htm
Do you seriously think those crews were happy to have radar
equipped patrol aircraft hunting them ?
In 1945 the Krigsmarine lost 150 U-boats to enemy aircraft
while sinking 99 merchant ships , compare and contrast that with
1940 when with far fewer boats they sank 564 ships while losing
24 U-boats.
Perhaps you will understand why this was considered by late
war crews as 'the happy time'
>
>
>
> http://books.google.com.au/books?id=FW_50wm8VnMC&pg=PA38&dq=radar+type+XXI+snorkel&lr=&as_brr=3
> "Fast Snorkel Boats Succh as the Type XXI were practivally impervious
> to radar"
>
> http://books.google.com/books?id=uYgsr3exvS4C&pg=PA115&lpg=PA115&dq=x-geraete+first+use&source=bl&ots=AlMxNdhdQH&sig=J6Yq9XA6umgFS_fqwdrjJokwNwk&hl=en&ei=hR_zSeHBGaDYswOw3ZjkCg&sa=X&oi=book_result&ct=result&resnum=1
>
> "Radar techniques succeded in hiding the snorkel"
>
> You've fabricated all of that and its clearly nonsense. The
> designers of the Kriegsmarines RAM coating took mearements and worked
> out that the Wesch absorbers cut detection range in half.
>
> It's rather dumb to think that men that can design such a coating
> wouldn't take measurments to try and see how effective they were...
>
Given that they made so many fundamental errors its entrirely believable.
In fact the main problem with detecting snorkels and periscopes was
filtering out the reflections from waves.
As for type XXI being impervious to radar I would point out
that a large number of them were indeed sunk by aircraft, for
example U-3523 was sunk by a radar equipped Liberator
in the Skagerrak in Jan 1945
>
> In fact they went further in testing the behaviour of the coating:
> they subjected actual snorkels in submarines to their own Microwave
> radars, the Berlin series which were mounted on Fw 200s. The thing to
> note is that the Wesch Abssrobers were particulary effective at both
> 3cm and 9cm which is all that was needed since that is all that the
> allies used. The weakeness was at 5cm a frequency the Allies didn't
> use. The Jaumann absorbers, which were physically thicker, was
> broadband and were 99% effrective from a few mm all the way to 20cm
> with no week spots from 0mm to 10cm.
>
Berlin was a 10cm radar
> The reality however is that the covered snorkels rendered ASV radar
> ineffective. Its fine to talk about picking up a snorkel in a flat
> sea while it is fully proud of the water in a test when the radar
> opperator knows there is a target there, quite another when the
> snorkel is boobing in a slight chop. As it turns out 10cm radar was
> well absorbed by the Wesch absorber while 3cm radar was absrobed only
> a little less.
>
> The reality was that in unsual circumstance, calm seas, snorkel and
> antean all out a radar camafaluged snorkel might be picked up at 5
> miles of so. On the same day a uncoated snorkel was detected at only
> 2.5 miles.
>
>
> The Wesch absrobers killed of 95% at 10cm and 90% at 3cm. At 3cm
> radar also pick up wave tops, porpoise and fish leaping, flotsame and
> jetsam, whale spouts etc. 3cm marined radar is not trusted for this
> reason.
It was in widespread use from the beginning of 1944 onwards in
the ASV Mk VII system
>
> The Jaumann absorbers, which were genrally fitted to few boats killed
> of 99.5% of reflections and effectively cut detection range to 15%
> which is to say about 1km, which is next to useless. A few type 23
> seem to have gotten Jaumann types.
>
>
So 99% of German U-Boats did NOT have it.
>>
>> Reality is a bitch.
>
>
> Delusion is your bitch.
>
> Incidently to this day anti submarine radar has not recovered its
> abillity to detect snorkels, masthead stealth has evolved.
>
BWAHAHA
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0527981
http://books.google.co.uk/books?id=l-DzknmTgDUC&pg=PA210&lpg=PA210&dq=AN/APS-116+Radar+System&source=bl&ots=2rePIUpdFg&sig=2ES8LM7MmEcHDAXUWleFlckAqSQ&hl=en&ei=MrpQSoCXNdDLjAfEnqHCBQ&sa=X&oi=book_result&ct=result&resnum=10
<Quote>
Performance in test
26nm - Snorkel from aircraft at 1500ft
</Quote>
The APS 116/137 is widely fitted to ASW aircraft and helicopters
See my earlier statement regarding female dogs and reality
Keith
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:6f408e6f-339f-4dd8...@l35g2000pra.googlegroups.com...
On Jul 4, 2:46 am, "Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
>
> news:c296a1fa-9fd8-4dbb...@v23g2000pro.googlegroups.com...
> On Jul 3, 4:54 pm, Gordon <Gor...@oldboldpilots.org> wrote:
>
>
>
>> >> Even the guys running the build, (tom somebody?) stated flatly that
>> >> "its obvious that stealth was not considered by the Horten
>> >> brothers" (paraphrasing, but accurate). Their wartime papers don't
>> >> mention anything about stealth at all.
>> > Reimers 1950s paper delivered in Argentina mentions 'wood' as being
>> > "Radar Camflauge".
>
> Yet the DH Mosquito was clearly visible on German radars
>
No response I note
> > As reflection of electric waves on metallic surfaces is
> > good, such is the image on the radar screen; on the contrary, on wood
> > surfaces, that reflection is little, these resulting barely visible on
> > the radar. "
>
> The DH Vampire had a plywood construction too - does that
> make it the worlds first stealthy jet ?
> No, for two reasons:
> 1 the shape is not a flying wing and so there are more radar traps
> 2 there was apparently no use of graphite in the construction of the
> plywood. the Jury is out on whether the Hortens 'knew' that the
> graphite would have slightly improved RCS.
And the evidence that graphite is a magical stealth bullet is what exactly ?
> I would say that it would have had one of the lowest RCS since it
> lacked propellors and the Goblin engine was well hidden alebeit within
> metal ducts that would have acted as a waveguide.
Yet the DH Vampire is easily visible on radar.
The reason is simple. Combat aircraft are stuffed full of radar reflectors
control cables, oxygen bottles , electical wiring, guns engines, fuel tanks
etc. This is why taking a wooden airframe mockup and sticking it
on a pole at a radar test range is a meaningless exercise. The RAE
take fully equipped aircraft and use them for the testing. Why do you
think this is ?
Keith
Paul J. Adam
> Incidently to this day anti submarine radar has not recovered its
> abillity to detect snorkels, masthead stealth has evolved.
And so have the sensors. You'll find few submariners willing to keep
masts raised when they detect certain radars...
--
He thinks too much, such men are dangerous.
Gordon
<paulNOT.jTHESE.adamB...@googlemail.com> wrote:
> eunome...@yahoo.com.au wrote:
> > Incidently to this day anti submarine radar has not recovered its
> > abillity to detect snorkels, masthead stealth has evolved.
>
> And so have the sensors. You'll find few submariners willing to keep
> masts raised when they detect certain radars...
As late as a few years ago, finding their "racks" on my radar was my
primary way of detecting submarines. There's a lil U-boat captain in
the heart of all of them and they can't help coming shallow for a
peek.
v/r Gordon
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> <eunome...@yahoo.com.au> wrote in message
>
> news:01431c37-12ea-4932...@i8g2000pro.googlegroups.com...
>
> > On Jul 4, 2:56 am, "Keith Willshaw"
> > <ke...@nospam.kwillshaw.demon.co.uk> wrote:
> >> <eunome...@yahoo.com.au> wrote in message
>
> >>news:9db002ea-4c92-414a...@d2g2000pra.googlegroups.com...
> >> On Jul 2, 6:08 pm, "Keith Willshaw"
>
> >> >> And a big part of the RCS of an engine are the reflections of the
> >> >> RADAR off the inlet ducting , which acts as a wave guide and
> >> >> the spinning compressor blades which on a radar sparkles like
> >> >> a Catherine wheel.
> >> > A bigger part of the RCS of an aircraft is the absence of prescence of
> >> > propellors which double to quadrouple the RCS of an aicraft.
>
> >> Lets see some evidence for that claim please
>
> > In fact with a high PRF radar it can increase it by 30 fold.
>
> Thats an unsupported assertion - not evidence.
FFS the links are in this post.
>
I really have already presented most of my arguments, and they are
quite detailed.
> >http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+pro...
>
> > A Nimrod incidently has a significantly lower cross section than a
> > Orion, something which was emphaised when the aircraft was upgraded
> > from spey to BR715.
>
> Nobody claims the Nimrod is stealthy now do they ?
It would help a little in very early warning radar so yes it is an
advantage as to whether the aircraft is detectected at 250 miles or
200.
>
>
>
> > I'm a graduate electrical engineer, and though I work in the field of
> > auoimation, I've had plenty of training in the field of radio wave
> > propagation in various media. An electrical engineering degree puts
> > one throught years of hell in this area of studying impedence
> > matching, dielectric media, skin depth etc. There is nothing
> > magical about absorbing radar waves: its what antena and receiver
> > design is all about.
>
> Nobody has suggested sorcery was involved
>
> > Textbooks on radar, even those not dealing with stealth, touch on RCS
> > and most particularly the effect of propellor modulations.
> > Even in WW2 the Germans used "Nurenburg" a device that listened
> > through window to given an audiable tone of an aircrafts propellors
> > to help the opperator reacquire a signal he might have lost. If
> > those prop frequencies were moudlated with an FM signal and displayed
> > on an x-y scope one would have the fourier spectrum which could be
> > matched to blade number and prop rpm to indentify aircraft type.
>
> Nurenburg
>
>
>
> >> > Its true that the first stage compressors would still reflect radar
> >> > but out aircraft would still have a fraction of the RCS of a
> >> > conventional aircraft.
>
> >> Another claim made without ANY facts to validate it
>
> > My claims are so transparently obvious and easy to verify I find it
> > mind boggling that i should need to verity them for you. If you were
> > some teenager I might have put in the effort to help, but your grown
> > up I think and I would've thought that you wouldn't have need such
> > basic help.
>
> > google RCS propellor
> >http://books.google.com.au/books?id=qP7HvuakLgEC&pg=PA1049&dq=RCS+pro...
>
> A table of RCS of different classes of aircraft - interwsting but it hardly
> proves your point
So a single prop Piper light plane has an RCS of 2 and a learjet and a
T-38 1 doesn't ring bells.
>
> > In fact if a prop blade changed 1/3 of a degree the RCS area of a B-26
> > could increase by a factor of 23!
>
> >http://books.google.com.au/books?id=qZlrReU-cMkC&pg=PT28&dq=radar+cro...
>
> None of which address the issue of the RCS of a propellor compared with
> those
> of a turbo jet. Indeed this book deals extensively with the necessity to
> screen the compressor which as it says reflects radar very effectively.
> It also mentions that jet intakes form re-entrant structures that have a
> very high RCS.
Prop = Really big RCS
Turbo Jet small to medium RCS
Sheielded Turbojet tiny RCS
Surging but only at high altitudes from 33,000ft to 37,000ft and it
was dealt with by lowering RPM about 100-200. The flameouts were a
combination of poor control response to throttle changes and poor
atomisation by the nozzles. Stall wasn't the issue except in as much
as surging compelled an RPM and therefore airflow reduction.
>
> > There was not a compressor stall problem, there was a surge problem at
> > high altitude and high speed that was dealt with by reducing engine
> > RPM a little (about 200 or so), this naturally caused a loss of power
> > and a reduction in airflow that started to make the fuel vapourisation
> > problem worse.
>
> Sorry old boy but the Jumo did indeed suffer with compressor stall
> particularly if the engine was throttled back too quickly. This is a
> problem with all axial flow engines which is one of the reasons
> Whittle picked the centrifugal compressor. To alleviate it Junkers fitted a
> governor to regulate engine acceleration and decelleration but all
> German pilots were well aware of the problem
Nope there was no compressor stall problem due to acceleration: up or
down. What you and the authors are thinking of is a 'flameout'.
The axial compressor does indee have its surge and choke points closer
to the best opperating point but in the case of the Jumo 004B there
was no surge or choking problem due to compressor acceleration. The
low compression ratio more or less precluded choking.
There was a surge problem at RPM above 8750 and at above 37,000ft that
combined with other problems generally limited the Jumo 004B to
33,000ft.
The engine flameouts were caused predominatly by excessive fuel
starvation due to the over reaction of the fuel control system which
being a primitve centrifugal governor only based system over dosed
fuel beyond the physical capacity of the spool to accelerate (due to
inertia and load) and therefore overheated the engine if the throttle
was moved up to fast. Conversely if the throttle was moved down to
fast the fuel system would reduce the flow faster than the compressor
could spin down.
There are many ways to deal with this: preventing rapid fuel pressure
changes or measureing pressure changes accross the compressor and
limiting fuel flow untill those changes stabalise.
The other design insufficiency was a failure to for the control system
to measure inlet pressure and adapt to lower density air at high
altitudes by reducing fuel flow proportionate to the reduced air
density, this meant the governor had to accomodate for a wide flow
range on its own and made it even more 'peeky' in its behaviour.
At low air flow rates as was the case at high altitudes and idling the
fuel nozzles were also low and did not vaporise the fuel properly,
this was the other cause of flameouts.
Compressor stall was not a problem.
The soltion to all these issues: the more sophisticated fuel control
system with the 'accelerator valve' and high/low range 'duplex
nozzles' never made it into service though they do seem to have been
flown on test aircraft.
>
> see
> Jagdgeschwader 7 'Nowotny'
> By Robert Forsyth, Jim Laurier
Forsyth and Laurier are simply wrong if they said that the
'accelerator valve' entered sevice on the Jumo 004 or flew with
commando Nowotny.
The valve was long awaited but was only scheduled for service entry in
the second week of April. Had it entered service engine life would
have doubled.
http://www.cdvandt.org/ktb-chef-tlr.htm
http://www.cdvandt.org/ktb-tlr_part_8.htm
"109 - 004 (Junkers: Jumo jet engine, AOB)
Vorschau am Monatsanfang 1000, am Monatsende 900, geliefert 876.
Mehrfache Forderung eines Einbaues eines Beschleunigungsventils,
welches die Aufgabe hat, unzulässige Überheizung des Triebwerks bei
plötzlichem Gas geben zu vermeiden. Einführung bei der Truppe und
soweit vorhanden in der Serie bis Anfang April 1945 vorgesehen."
"Anticpated Production Target at the beginning of the month 1000, at
the end of month 900, delivered 876.
Extensive efforts at expediting the installation of an accelerator
valve, which has the task over preventing over heating of the engine
when a throttle demand. Introduction of the Force and to the extent
available in the series until early April 1945 provided for.
>
> > Duplex nozzles provided for vapurisation at low flow rates and the
> > 'accelerator valve' would have fixed the problem of fuel starvation
> > from rapid throttle movement. The BMW 003 had the accelerator valve.
> > The Jumo 004D was to get all of the above and had a new compressors to
> > deal with these issues as well.
>
> > It wouldn't effect the intake at all since the physical geometry would
> > be uneffected: I'm assuming that the the inlet duct is not part of the
> > engine proper while the inlet cone is merely a metal cap. It would be
> > turned into a whitches had like cone and covered with a biconvex
> > curve.
>
> More unsupported assertions.
Anthony Kay German Gas Turbine and Jet Engine Development 1934-1945.
>
>
>
> >> You also seem to have missed the little fact that RAM tend to be
> >> effective
> >> against a limited frequency range which is why the Kriegsmarine were
> >> happily assuming there RAM treated snorkels were invisible when in
> >> fact the British centimetric radar could pick them up at 5 miles.
>
> > There were two centrimetric radars, at 10cm and 3cm. Both were
> > greatly deteriorated by the basic RAM (Wesch) and rendered useless by
> > the advanced RAM (Jaumann).
>
> Which seems to have been fielded in a very small number of boats
> if at all.
>
> > It must also be pointed out that by Feb 1944 the Germans had radar
> > detectors for 10cm and 3cm ASV radar. The first experimental RAM clad
> > snorkel boats didn't however appear till October 1944.
>
> Nope. They had Naxos which worked at 10cm but the 3cm detector was not
> available until spring 1945 and less than 100 had been assembled
> while the RAF had been using 3cm radar for over a year - oops
Naxos was a Luftwaffe device adapted to the navy and then modified for
3cm. The German Navy however had several micowave detectors to cover
the 2cm to 10cm band.
FuMB 26 - Tunis Radar detector - combined FuMB 24 Cuba Ia - Fleige
(for 8-23 cm wavelengths) and FuMB 25 - Mücke (for 2-4 cm wavelengths)
antennas back to back
FuMB 35 - Athos Radar detector covered X (2.5-4 cm) and S (8-15 cm)
bands with a cylinder-shaped water/pressure resistant array of
circular loop antennas
http://www.uboatarchive.net/KTBNotesCommunications.htm
FuMB 25 detected 2-4cm and was in service from April 1944.
>
> http://www.uboat.net/technical/detectors.htm
>
Not a good source on this topic.
> > A late war u-boat would have been delighted to have british patrol
> > aircraft anouncing their bearing and presecene with a nice big radar
> > signal. It greatly simplified their lookout task since they were more
> > vulnerable to visual detection at dawn or dusk than radar detection.
>
> German U-boat crews were less sanguine, not surprising given how many
> were lost to airborne attack. It is no coincedence that the closing of the
> air gap in the North Atlantic by radar equipped Liberators happened
> in the run up to the crisis of the Battle of The Atlantic. From that point
> on there was no period when it was safe to be on the surface. As for
> snorkels thet are indeed useful but the North Atlantic is not conducive
> to their use.
>
The Nth Atlantic is fine for them, the first generation of snorkels
was simply a bit primitive as was the depth keep gear.
> Take a look at the table of U-boat losses in 1943/4/5 and note how many
> were to aircraft.http://www.uboat.net/fates/losses/1943.htmhttp://www.uboat.net/fates/losses/1944.htmhttp://www.uboat.net/fates/losses/1945.htm
And it shows virtually no loss of submerged u-boats:
The first radar camaflauged snorkels were introduced in october
1944.
Out of 129 u-boats lost from Jan 1945 to the end of the war only 25
were lost due to aircraft.
Of those 25 aircraft the bulk were destroyed by rocket firing
Mosquito, Beufighters, bombing while in dock or moored in harbour.
On the one occaision a Liberator sank a submerged u-boat by detecting
a snorkel it was by visully detecting the snorkel in twilight.
U-681: struck a rock and forced to surface and then sunk by
liberators.
U-681 bombed in its dock by US bombers
U-2509 bombed in shipyard
U-2514 bombed in Hamburg Harbour
U-3512 Sunk 8 April, 1945 at Kiel, by bombs. Wreck broken up.
U-804 sunk by mosquitos firing rockets
U-1017
A Liberator (RAF Sqdn 120/Q, pilot F/O H.J. Oliver) spotted the wake
and smoke from a snorkel northwest of Ireland and attacked successful
with four depth charges and a Fido homing torpedo.
Note the absence of radar contact.
There are a few u-boats sunk where there is no note of how they were
detected: suface detected, MAD, sonar buoys or radar but little
indication that radar picked up a snorkel and less that it was a
camaflauged snorkel.
>
> Do you seriously think those crews were happy to have radar
> equipped patrol aircraft hunting them ?
>
> In 1945 the Krigsmarine lost 150 U-boats to enemy aircraft
> while sinking 99 merchant ships , compare and contrast that with
> 1940 when with far fewer boats they sank 564 ships while losing
> 24 U-boats.
And it was to late to introduce the new technology in any numbers,
high speed boats, radar camafaluged snorkels, mast head broad band
radar detectors, anachoic coatings. In addition widespread use of
UKWD, and Kurier in its 3F mode would have made ultra decrypts
impossible.
>
> Perhaps you will understand why this was considered by late
> war crews as 'the happy time'
>
>
>
> >http://books.google.com.au/books?id=FW_50wm8VnMC&pg=PA38&dq=radar+typ...
> > "Fast Snorkel Boats Succh as the Type XXI were practivally impervious
> > to radar"
>
> >http://books.google.com/books?id=uYgsr3exvS4C&pg=PA115&lpg=PA115&dq=x...
>
> > "Radar techniques succeded in hiding the snorkel"
>
> > You've fabricated all of that and its clearly nonsense. The
> > designers of the Kriegsmarines RAM coating took mearements and worked
> > out that the Wesch absorbers cut detection range in half.
>
> > It's rather dumb to think that men that can design such a coating
> > wouldn't take measurments to try and see how effective they were...
>
> Given that they made so many fundamental errors its entrirely believable.
> In fact the main problem with detecting snorkels and periscopes was
> filtering out the reflections from waves.
>
> As for type XXI being impervious to radar I would point out
> that a large number of them were indeed sunk by aircraft, for
> example U-3523 was sunk by a radar equipped Liberator
> in the Skagerrak in Jan 1945
No indication that a radar contact on a submerged boat was involved in
anyway. In fact it is assumed that U-3523 fell to this aircraft.
>
>
>
> > In fact they went further in testing the behaviour of the coating:
> > they subjected actual snorkels in submarines to their own Microwave
> > radars, the Berlin series which were mounted on Fw 200s. The thing to
> > note is that the Wesch Abssrobers were particulary effective at both
> > 3cm and 9cm which is all that was needed since that is all that the
> > allies used. The weakeness was at 5cm a frequency the Allies didn't
> > use. The Jaumann absorbers, which were physically thicker, was
> > broadband and were 99% effrective from a few mm all the way to 20cm
> > with no week spots from 0mm to 10cm.
>
> Berlin was a 10cm radar
The Germans had 3cm microwave sources. Three centimeter radar
effectively makes the problem of false targets worse and ultimatly
make the job of creating a RAM coating easier.
>
> > The reality however is that the covered snorkels rendered ASV radar
> > ineffective. Its fine to talk about picking up a snorkel in a flat
> > sea while it is fully proud of the water in a test when the radar
> > opperator knows there is a target there, quite another when the
> > snorkel is boobing in a slight chop. As it turns out 10cm radar was
> > well absorbed by the Wesch absorber while 3cm radar was absrobed only
> > a little less.
>
> > The reality was that in unsual circumstance, calm seas, snorkel and
> > antean all out a radar camafaluged snorkel might be picked up at 5
> > miles of so. On the same day a uncoated snorkel was detected at only
> > 2.5 miles.
>
> > The Wesch absrobers killed of 95% at 10cm and 90% at 3cm. At 3cm
> > radar also pick up wave tops, porpoise and fish leaping, flotsame and
> > jetsam, whale spouts etc. 3cm marined radar is not trusted for this
> > reason.
>
> It was in widespread use from the beginning of 1944 onwards in
> the ASV Mk VII system
3cm detectors were in use from April 1944 though they functioned only
on a surfaced uboat.
>
>
>
> > The Jaumann absorbers, which were genrally fitted to few boats killed
> > of 99.5% of reflections and effectively cut detection range to 15%
> > which is to say about 1km, which is next to useless. A few type 23
> > seem to have gotten Jaumann types.
>
> So 99% of German U-Boats did NOT have it.
Nope, but Wesch was effective.
>
>
>
> >> Reality is a bitch.
>
> > Delusion is your bitch.
>
> > Incidently to this day anti submarine radar has not recovered its
> > abillity to detect snorkels, masthead stealth has evolved.
>
> BWAHAHA
>
>
> <Quote>
> Performance in test
> 26nm - Snorkel from aircraft at 1500ft
> </Quote>
>
> The APS 116/137 is widely fitted to ASW aircraft and helicopters
Firstly its not a very sophisticated anti sonar radar at all. Some of
the SAR types are a serious threat.
So you believe the advertisement? Somewhat gullible and unrealistic.
The threat to a snorkelling sub comes from the noise of its diesels
and dunking sonar. Certainly a snorkel must be withdraw upon a radar
contact. Modern snorkels also track the level of the sea, some are
able to skim it by only a few inches.
>
> See my earlier statement regarding female dogs and reality
Blah blah blah
>
> Keith
Keith Willshaw
"Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
news:atlas-bugged-09DC...@aries.ka.weretis.net...
> In article
> <qZi2m.10511$Cq3....@newsfe04.ams2>,
> "Keith Willshaw"
> <ke...@nospam.kwillshaw.demon.co.uk>
> wrote:
>
>> "Otis Willie PIO The American War Library" <themilit...@pacbell.net>
>> wrote in message news:qfmi45tea0bl0gu61...@4ax.com...
>> > NGC's 'Hitler's Stealth Fighter' premieres Sunday, June 28
>> > http://www.monstersandcritics.com/smallscreen/news/article_1486306.php/NGCs_
>> > Hitlers_Stealth_Fighter_premieres_Sunday_June_28
>> >
>> > {EXCERPT} Monsters and Critics.com, April MacIntyre During World War
>> > II,
>> > brothers Walter and Reimar Horten designed a prototype for a German
>> > stealth plane that, if completed, could have changed history as we...
>> >
>> >
>>
>> I do wish somebody would take a clue stick to the tv producers who dish
>> up
>> this rubbish
>>
>> Making aircraft of wood does NOT make an aircraft stealthy. The large
>> rotating masses in the engines of the proposed Horten aircraft would
>> have given them a massive radar signature.
>>
>
> Not according to the testing they did
>
They didnt test the aiframe with engines in it - that's the point.
Keith
Keith Willshaw
<euno...@yahoo.com.au> wrote in message
news:fb4e6267-26b8-4abe...@m3g2000pri.googlegroups.com...
On Jul 6, 12:59 am, "Keith Willshaw"
>
>> > Both problems has been solved by Feb 1945 and were to be delivered in
>> > march/april. I can verifty that with Luftwaffe corresponence.
>
>> Indeed but the compressor stall problem remained
>
> Surging but only at high altitudes from 33,000ft to 37,000ft and it
> was dealt with by lowering RPM about 100-200. The flameouts were a
> combination of poor control response to throttle changes and poor
> atomisation by the nozzles. Stall wasn't the issue except in as much
> as surging compelled an RPM and therefore airflow reduction.
Axial flow compressors are prone to stall with changes in aerodynamic
conditions. modern engines solve the problem with variable incidence
blades. The Jumo didnt have them.
>
>> > There was not a compressor stall problem, there was a surge problem at
>> > high altitude and high speed that was dealt with by reducing engine
>> > RPM a little (about 200 or so), this naturally caused a loss of power
>> > and a reduction in airflow that started to make the fuel vapourisation
>> > problem worse.
>
>> Sorry old boy but the Jumo did indeed suffer with compressor stall
>> particularly if the engine was throttled back too quickly. This is a
>> problem with all axial flow engines which is one of the reasons
>> Whittle picked the centrifugal compressor. To alleviate it Junkers fitted
>> a
>> governor to regulate engine acceleration and decelleration but all
>> German pilots were well aware of the problem
> Nope there was no compressor stall problem due to acceleration: up or
> down. What you and the authors are thinking of is a 'flameout'.
Flameout is a symptom , compressor stall is one of the causes.
> The axial compressor does indee have its surge and choke points closer
> to the best opperating point but in the case of the Jumo 004B there
> was no surge or choking problem due to compressor acceleration. The
> low compression ratio more or less precluded choking.
Not according to those who built and flew it
I recommend the book
Aeronautical research in Germany
By Ernst-Heinrich Hirschel, Horst Prem, Gero Madelung
pages 407-409 deal in details with the surge and stall problems
found with the Jumo 004 engine and the measures taken to
alleviate them.
<snip>
> Compressor stall was not a problem.
Repeating a mantra doesnt make it true.
> The soltion to all these issues: the more sophisticated fuel control
> system with the 'accelerator valve' and high/low range 'duplex
> nozzles' never made it into service though they do seem to have been
> flown on test aircraft.
So no solution was in fact fielded
<snip>
.
>>
>> Nope. They had Naxos which worked at 10cm but the 3cm detector was not
>> available until spring 1945 and less than 100 had been assembled
>> while the RAF had been using 3cm radar for over a year - oops
> Naxos was a Luftwaffe device adapted to the navy and then modified for
>3cm. The German Navy however had several micowave detectors to cover
> the 2cm to 10cm band.
> FuMB 26 - Tunis Radar detector - combined FuMB 24 Cuba Ia - Fleige
> (for 8-23 cm wavelengths) and FuMB 25 - M�cke (for 2-4 cm wavelengths)
> antennas back to back
FuMb 24 and FuMb 25 were simply codes for the naval installation
that was a combination of Metox and Naxos .
see Kriegsmarine U-boats, 1939-45
By Gordon Williamson, Ian Palmer
Tunis came in two versions, 9.1 cm and 3cm, the latter required a horn
antenna as
distinct from the dipole antenna fitted to the 9.1 cm version. First
deliveries
of Tunis were made in August 1944, they were primarily in 9.1 cm
Total production of 3cm detectors (Naxos Zc) reached around 500 - first
priority went to the Luftwaffe
> FuMB 35 - Athos Radar detector covered X (2.5-4 cm) and S (8-15 cm)
> bands with a cylinder-shaped water/pressure resistant array of
> circular loop antennas
> http://www.uboatarchive.net/KTBNotesCommunications.htm
Yep but it was never fielded, aka as Naxos Zd it was never to enter
production
See
> FuMB 25 detected 2-4cm and was in service from April 1944.
>>
>> http://www.uboat.net/technical/detectors.htm
>>
> Not a good source on this topic.
but better than a list of code names
see also
http://www.baermann.biz/pauke/index.php?itemid=128
see also the paper published by the Centre for German Communication and
related technology
NAXOS, THE HISTORY OF A GERMAN MOBILE RADAR DIRECTION FINDER 1943-1945
� Arthur O. Bauer
>> > A late war u-boat would have been delighted to have british patrol
>> > aircraft anouncing their bearing and presecene with a nice big radar
>> > signal. It greatly simplified their lookout task since they were more
>> > vulnerable to visual detection at dawn or dusk than radar detection.
>>
>> German U-boat crews were less sanguine, not surprising given how many
>> were lost to airborne attack. It is no coincedence that the closing of
>> the
>> air gap in the North Atlantic by radar equipped Liberators happened
>> in the run up to the crisis of the Battle of The Atlantic. From that
>> point
>> on there was no period when it was safe to be on the surface. As for
>> snorkels thet are indeed useful but the North Atlantic is not conducive
>> to their use.
>
> The Nth Atlantic is fine for them, the first generation of snorkels
> was simply a bit primitive as was the depth keep gear.
You really dont understand I fear, depth keeping isnt the issue, 30 ft
waves are the problem. Having the float valve atop the snort slammed
shut by a wavetop is a seriously uncomfortable experience
>> Take a look at the table of U-boat losses in 1943/4/5 and note how many
>> were to
> And it shows virtually no loss of submerged u-boats:
It makes no mention of whether they were submerged or on the surface
so that answer is technically correct but somewhat misleading.
> The first radar camaflauged snorkels were introduced in october
> 1944.
Which does nothing to support your claim that :
>> > A late war u-boat would have been delighted to have british patrol
>> > aircraft anouncing their bearing and presecene with a nice big radar
>> > signal.
> Out of 129 u-boats lost from Jan 1945 to the end of the war only 25
> were lost due to aircraft.
Indeed , they were staying at home and staying submerged when they
did go out, why do you think this was ?
> Of those 25 aircraft the bulk were destroyed by rocket firing
> Mosquito, Beufighters, bombing while in dock or moored in harbour.
Indeed , putting to sea was rather risky after all
<snip>
>>
>> Do you seriously think those crews were happy to have radar
>> equipped patrol aircraft hunting them ?
>>
>> In 1945 the Krigsmarine lost 150 U-boats to enemy aircraft
>> while sinking 99 merchant ships , compare and contrast that with
>> 1940 when with far fewer boats they sank 564 ships while losing
>> 24 U-boats.
> And it was to late to introduce the new technology in any numbers,
No kidding :)
> high speed boats, radar camafaluged snorkels, mast head broad band
> radar detectors, anachoic coatings. In addition widespread use of
> UKWD, and Kurier in its 3F mode would have made ultra decrypts
> impossible.
Not to mention useless with the Kriegsmarine ports occupied by
the armies of Britain, the USA and USSR
>
<snip>
>
>> As for type XXI being impervious to radar I would point out
>> that a large number of them were indeed sunk by aircraft, for
>> example U-3523 was sunk by a radar equipped Liberator
>> in the Skagerrak in Jan 1945
>No indication that a radar contact on a submerged boat was involved in
>anyway. In fact it is assumed that U-3523 fell to this aircraft.
There's no indication it was not either way clearly radar equipped aircraft
WERE a threat to the type XXI
<snip>
>
>>> It was in widespread use from the beginning of 1944 onwards in
>>> the ASV Mk VII system
> 3cm detectors were in use from April 1944 though they functioned only
> on a surfaced uboat.
Repeating that same tired mantra again I see. I note that you have
now dropped the claim that 3cm radar wasnt used for marine systems.
After all if that was the case the Kriegsmarine would hardly have needed
a detector for it.
<snip>
>
>> > Incidently to this day anti submarine radar has not recovered its
>> > abillity to detect snorkels, masthead stealth has evolved.
>>
>> BWAHAHA
>>
> > http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identi...http://books.google.co.uk/books?id=l-DzknmTgDUC&pg=PA210&lpg=PA210&dq...
>
> <Quote>
>> Performance in test
>> 26nm - Snorkel from aircraft at 1500ft
>> </Quote>
>>
>> The APS 116/137 is widely fitted to ASW aircraft and helicopters
> Firstly its not a very sophisticated anti sonar radar at all. Some of
> the SAR types are a serious threat.
APS 137 is a syntheitc aperture version of APS 116 - Doh !
>> So you believe the advertisement? Somewhat gullible and unrealistic.
I believe the customer list (which includes Australia) and the ex
bubbleheads
who I have discussed this with and of course Jane's
> The threat to a snorkelling sub comes from the noise of its diesels
> and dunking sonar. Certainly a snorkel must be withdraw upon a radar
> contact.
You have been claiming radar can't see it, that seems somewhat inconsistent
> Modern snorkels also track the level of the sea, some are
> able to skim it by only a few inches.
Let me introduce you to a new phrase - WAVE HEIGHT, the North
Atlantic has some whoppers.
Keith
Malcom "Mal" Reynolds
<4Pq4m.32868$TT5...@newsfe18.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
I believe they tested it with metalized
tape that was supposed to simulate the
RCS of engines...something they have had
experience with
Keith Willshaw
"Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
Except of course that its not an adequate substitute, see other posts
in this thread. A rotating compressor provides a very strong returm
which is why modern stealth aircraft put the inlets on the upper
surface of the wing and use a mesh cover over the inlet.
Then there is the little matter of all the radar reflectors in a real
aircraft, guns, control wires, o2 bottles , wiring etc
When the RAE wants to test the radar signature of an aircraft they
dont put a wooden mockup on a pole
Keith
Dan
I would suppose the Pole gets burned from the microwaves. Wouldn't
have increased cancer risks over the long term?
Dan, U.S. Air Force, retired
Malcom "Mal" Reynolds
<kov4m.18442$FP6....@newsfe16.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
How often does the RAE test 65 year old
designs?
Keith Willshaw
"Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
>>
>> When the RAE wants to test the radar signature of an aircraft they
>> dont put a wooden mockup on a pole
>>
>> Keith
>
> How often does the RAE test 65 year old
> designs?
>
Not very often but that doesnt alter the fact that its the only accurate
method of testing the RCS
Keith
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> "Malcom "Mal" Reynolds" <atlas-bug...@invalid.invalid> wrote in messagenews:atlas-bugged-5944...@aries.ka.weretis.net...
>
>
>
>
>
> > In article
> > <4Pq4m.32868$TT5...@newsfe18.ams2>,
> > "Keith Willshaw"
> > <ke...@nospam.kwillshaw.demon.co.uk>
> > wrote:
>
> >>news:atlas-bugged-09DC...@aries.ka.weretis.net...
> >> > In article
> >> > <qZi2m.10511$Cq3.10...@newsfe04.ams2>,
> >> > "Keith Willshaw"
> >> > <ke...@nospam.kwillshaw.demon.co.uk>
> >> > wrote:
>
> >> >> "Otis Willie PIO The American War Library"
> >> >> wrote in messagenews:qfmi45tea0bl0gu61...@4ax.com...
> >> >> > NGC's 'Hitler's Stealth Fighter' premieres Sunday, June 28
A propellor provides a much larger return than a engine recesed into
the leading edge of a flying wing. to me the compressor of a jet
would seem to have 1/4 or less return than a propeller of a similar
sized aircraft.
>
> Then there is the little matter of all the radar reflectors in a real
> aircraft, guns, control wires, o2 bottles , wiring etc
The production Ho 229 would have been made of a plywood that
sandwitches a carbon black rich plastic wood core about 2 to 2.5cm
thick.
Carbon black is semiconductive, its is used in cables for this
purpose. Due to its semiconductive nature it will tend to absorb
some of the energy of the radar pulse before it gets to metal under
the wings. It will also tend to reflect some, it will also reflect
some from its back surface which will intefere destructively a little
with the incident wave. This effect is not very strong due to the
lack of geometry. Due to the shape of the flying wing a higher
proportion will tend to be reflected away from the aircraft.
The Jauman absorbers consisted of 6-7 carbon black laced
semiconductive layers of exponetialy increasing conductivity. The
refelections from the interfaces would reflect and destructively
interfere with the incident wave and be absorbed by the
semicondiuctive material. Because the the seven layers there would
always be nearly perfect interference.
>
> When the RAE wants to test the radar signature of an aircraft they
> dont put a wooden mockup on a pole
I bet they do from time to time.
If you are testing an F-22 or F-117 you are testing a design with a
radar cross section of less than 0.001 that will lose its stealth
abillity if there is a bird dropping or a buildup of moisture so in
that case you are testing signals down to the nanowatt so an emc
aeocahoic chamber is neccesary to prevent backgound interference (from
say cell phones) from upsitting the tiny measurement since exateaneous
background noise, not matter how weak will be relatively high compared
to a test signal and will make a significant proportion of the
measurements made. The Ho 229 probably had a radar cross section of
0.4 sqm which is about 1/5th that of a single engine piston fighter
and the effort of a EMI/EMC anachoic chamber is simply not neccesary.
Malcom "Mal" Reynolds
<rHC4m.10350$u13....@newsfe07.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
> "Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
How accurate did it need to be?
Keith Willshaw
"Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
Accurate enough to support a claim of 'stealth'
Keith
David E. Powell
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> "Malcom "Mal" Reynolds" <atlas-bug...@invalid.invalid> wrote in messagenews:atlas-bugged-1585...@aries.ka.weretis.net...
>
>
>
>
>
> > In article
> > <rHC4m.10350$u13.5...@newsfe07.ams2>,
> > "Keith Willshaw"
> > <ke...@nospam.kwillshaw.demon.co.uk>
> > wrote:
>
> >> "Malcom "Mal" Reynolds" <atlas-bug...@invalid.invalid> wrote in message
> >>news:atlas-bugged-BE6D...@aries.ka.weretis.net...
>
> >> >> When the RAE wants to test the radar signature of an aircraft they
> >> >> dont put a wooden mockup on a pole
>
> >> >> Keith
>
> >> > How often does the RAE test 65 year old
> >> > designs?
>
> >> Not very often but that doesnt alter the fact that its the only accurate
> >> method of testing the RCS
>
> >> Keith
>
> > How accurate did it need to be?
>
> Accurate enough to support a claim of 'stealth'
>
> Keith
Was this how the Have Blue mockup was tested for the F-117 program?
Keith Willshaw
"David E. Powell" <David_Po...@msn.com> wrote in message
news:a49f3132-440f-4742...@l31g2000yqb.googlegroups.com...
On Jul 8, 3:20 am, "Keith Willshaw"
>> > How accurate did it need to be?
>
>> Accurate enough to support a claim of 'stealth'
>>
>> Keith
> Was this how the Have Blue mockup was tested for the F-117 program?
Yes - two were built, one to test both the flight dynamics and the
radar stealth aspects. The latter was tested both on the range and
in flight over fixed radar systems
Keith
Malcom "Mal" Reynolds
<NMX4m.30829$_d3....@newsfe03.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
> "Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
> news:atlas-bugged-1585...@aries.ka.weretis.net...
> > In article
> > <rHC4m.10350$u13....@newsfe07.ams2>,
> > "Keith Willshaw"
> > <ke...@nospam.kwillshaw.demon.co.uk>
> > wrote:
> >
> >> "Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
> >> news:atlas-bugged-BE6D...@aries.ka.weretis.net...
> >>
> >> >>
> >> >> When the RAE wants to test the radar signature of an aircraft they
> >> >> dont put a wooden mockup on a pole
> >> >>
> >> >> Keith
> >> >
> >> > How often does the RAE test 65 year old
> >> > designs?
> >> >
> >> Not very often but that doesnt alter the fact that its the only accurate
> >> method of testing the RCS
> >>
> >> Keith
> >
> > How accurate did it need to be?
> >
>
> Accurate enough to support a claim of 'stealth'
>
> Keith
I suppose that depends on the definition
of "stealth"
Keith Willshaw
"Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
>>
>> Accurate enough to support a claim of 'stealth'
>>
>> Keith
>
> I suppose that depends on the definition
> of "stealth"
Indeed, I dont doubt the machine would have had a lower RCS than
conventional bombers but to describe it as a stealth aircraft is to claim
it was undetectable by British radar.
Given that UK airspace was the most intensively monitored on the
planet at that time this is a biggie. By 1945 the airspace was monitored
by Chain Home on 30m wavelength, Chain Home Low on 1.5 m wavelength
and Chain Home Extra Low which was a centimetric system.
Producing a stealth system that works against 3 systems with such different
frequencies would be challenging to say the least.
Keith
guy
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> "Malcom "Mal" Reynolds" <atlas-bug...@invalid.invalid> wrote in messagenews:atlas-bugged-7F81...@aries.ka.weretis.net...
For more info on chain home try this (note multiple pages)
http://www.radarpages.co.uk/mob/ch/chainhome.htm
Guy
euno...@yahoo.com.au
<ke...@nospam.kwillshaw.demon.co.uk> wrote:
> "Malcom "Mal" Reynolds" <atlas-bug...@invalid.invalid> wrote in messagenews:atlas-bugged-7F81...@aries.ka.weretis.net...
>
>
>
> >> Accurate enough to support a claim of 'stealth'
>
> >> Keith
>
> > I suppose that depends on the definition
> > of "stealth"
>
> Indeed, I dont doubt the machine would have had a lower RCS than
> conventional bombers but to describe it as a stealth aircraft is to claim
> it was undetectable by British radar.
Stealth in reality doesn't mean undetecable, greatly reduced radar
returns means that the 'signal' seen by the receiver is much reduced.
This impacts on the signal to noise ratio or S/N ratio to the extet
that the detection range is reduced thereby making an interception
unlikely. The reduction in returned signal also means that
countermeasures in the form of chaff (Duppel as the Luftwaffe called
it) or noise jamming can be used to increase N or the noise to degrade
radare effectiveness.
UK radar was just as vulnerable to 'window' perhaps even moreso
however the tonage required to significantly degrade the UK's radars
was difficult to reach by the relatively small German raids.
>
> Given that UK airspace was the most intensively monitored on the
> planet at that time this is a biggie. By 1945 the airspace was monitored
> by Chain Home on 30m wavelength, Chain Home Low on 1.5 m wavelength
> and Chain Home Extra Low which was a centimetric system.
CH is unlikely to be degraded but CHL and CHEL would have been
vulnerable. However CH was ineffective against targets flying low and
was also somewhat inaccurate. This would have allowed a low level
penetration since CHL and CHEL were degraded slightly. Its not much
of a reduction in warning time: 20% (about 8-10 minutes degraded to
6-8 minutes) but it would have reduced opportunies for an interception
against a transonic aircraft already difficult to intercept. A low
level approach however does plave the aircraft at a level that the
Meteor was quite good in so the Ho 229 might in theory be intercepted
by the Meteor.
It was remarkable for a first attempt by competent aeronautical
engineers who knew little of the physics of radio waves. Its
probable that defficiencies of the Hortens crude stealth abillities
would have eventually promted advice from the German Navy
(Kriegsmarine) who had the 'Schonsteinfehger' program for developing
radar absorbing coatings and structuresn effective from 1.5m (the
first generation of ASV) througth to materials effective against
microwaves. This program came up with several materials of which two
were quite good and might have been built into the leading edges of
the wing.
>
> Producing a stealth system that works against 3 systems with such different
> frequencies would be challenging to say the least.
Early Warning Radars are less degraded by stealth materials and remain
a problem to this day however they are limited in their precsion,
costly and also vulnerable due to bulk.
Malcom "Mal" Reynolds
<e6h5m.812$Nl3...@newsfe01.ams2>,
"Keith Willshaw"
<ke...@nospam.kwillshaw.demon.co.uk>
wrote:
> "Malcom "Mal" Reynolds" <atlas-...@invalid.invalid> wrote in message
> news:atlas-bugged-7F81...@aries.ka.weretis.net...
>
> >>
> >> Accurate enough to support a claim of 'stealth'
> >>
> >> Keith
> >
> > I suppose that depends on the definition
> > of "stealth"
>
> Indeed, I dont doubt the machine would have had a lower RCS than
> conventional bombers but to describe it as a stealth aircraft is to claim
> it was undetectable by British radar.
Incremental improvements. The machine
would have had an advantage over most,
if not all, other aircraft. How that
advantage would have manifested itself
is debatable.
>
> Given that UK airspace was the most intensively monitored on the
> planet at that time this is a biggie. By 1945 the airspace was monitored
> by Chain Home on 30m wavelength, Chain Home Low on 1.5 m wavelength
> and Chain Home Extra Low which was a centimetric system.
>
> Producing a stealth system that works against 3 systems with such different
> frequencies would be challenging to say the least.
Probably, but it may have been stealthy
enough to cause problems...and really
isn't that an advantage?
>
> Keith
Gordon
bug...@invalid.invalid> wrote:
> > Producing a stealth system that works against 3 systems with such different
> > frequencies would be challenging to say the least.
>
> Probably, but it may have been stealthy
> enough to cause problems...and really
> isn't that an advantage?
Surely, but that advantage is not correctly labeled "stealth". A
lower RCS is not what earns that description, its a concerted effort
to address all aspects of a design that could be exploited through
radar signals. The _wartime_ papers of the Hortens utterly fail to
mention _anything_ like a desire to reduce radar cross section - its
easy to lay claim to it years after the fact but even their 1950
document leaves out any mention that this design was intentionally
built to evade radar. Stating that they became aware that their
designs were more difficult to see on radar is a long stretch from
saying, "We built a stealth bomber."
I have no problem accepting that the Ho-9 was less visible to radars
of its day than other similarly sized aircraft, but I think its best
accounted for by building a flying wing shape (no vertical surfaces,
wings blended into fuselage), giving it jet engines (no whopping huge
spinning metal disc out front), and finally using wood for the
expansive outer wing panels - NOT applying pencil to paper under a
title "stealth bomber", in an era that would not fully understand what
that term meant.
v/r Gordon
Malcom "Mal" Reynolds
<6517f1a0-9152-4f3e-9823-5aeb04b4ce98@d3
2g2000yqh.googlegroups.com>,
Gordon <Gor...@oldboldpilots.org>
wrote:
I'll mostly agree.