Modern plywood stealth?
David E. Powell
plywood? It would seem an idea, mixing wood and composite
construction. Indeed plywood is itself a composite material of layers
of glue and of wood.
The trick, of course, is working around the larger metal components.
flybywire
"David E. Powell" <David_Po...@msn.com> wrote in message
news:1f96d487-278a-43a6...@h17g2000pri.googlegroups.com...
Jim Yanik
the Hughes Spruce Goose was made mostly of epoxy-laminated birch veneer.
It was a very big airplane.I have a Wood Magazine article on it.
I wonder about the moisture content of wood affecting the "stealth"
characteristics of the laminate. also,I believe the carbon fiber used in
stealth construction acts as an absorbent of radar energy. Not totally,but
partial absorbtion.
BTW,there's a company that is making a laminated wood 2 seater sports
car.It uses a GM Northstar motor,was featured in Wood Magazine several
years ago.
--
Jim Yanik
jyanik
at
localnet
dot com
Keith Willshaw
"David E. Powell" <David_Po...@msn.com> wrote in message
news:1f96d487-278a-43a6...@h17g2000pri.googlegroups.com...
Not only is it possible it is widely done.
examples
JDT Mini-MAX
Fisher Dakota Hawk and FP-202
Bowers Fly Baby
Evans VP-2
Aircraft grade plywood is readily available.
Keith
Keith Willshaw
"Juergen Nieveler" <juergen.nie...@arcor.de> wrote in message
news:Xns9DC7E1EB4E9E...@nieveler.org...
> "David E. Powell" <David_Po...@msn.com> wrote:
>
>> Is there any reason a light aircraft on a budget could not use
>> plywood? It would seem an idea, mixing wood and composite
>> construction. Indeed plywood is itself a composite material of layers
>> of glue and of wood.
>
> Sure possible. Depends on what you want to use it for...
>
>> The trick, of course, is working around the larger metal components.
>
> Build a glider - worked at Eben-Emael and at Pegasus Bridge.
>
> Would the guns of the infantry squad inside show up on radar?
>
> --
> Juergen Nieveler
Yes
In his non fiction book Glide Path Arthur C Clarke mentioned
that the centimetric radar they were testing could pick
out the rifles of the sentries and bicycle being ridden
down the dispersal track.
Keith
Paul J. Adam
Nieveler <juergen.nie...@arcor.de> writes
>Build a glider - worked at Eben-Emael and at Pegasus Bridge.
>
>Would the guns of the infantry squad inside show up on radar?
Yes, and the Doppler signature is also distinctive. Low-observable isn't
cheap, simple or easy, especially when the enemy very unsportingly uses
multiple sensors and effectors.
>
--
He thinks too much, such men are dangerous.
Paul J. Adam
vaughn
> plywood? It would seem an idea, mixing wood and composite
> construction. Indeed plywood is itself a composite material of layers
> of glue and of wood.
>
factory made and homebrew. You can trust a tree.
Vaughn
Jim Wilkins
<keithnos...@kwillshaw.demon.co.uk> wrote:
> ...
>
> In his non fiction book Glide Path Arthur C Clarke mentioned
> that the centimetric radar they were testing could pick
> out the rifles of the sentries and bicycle being ridden
> down the dispersal track.
>
> Keith
The simple 10 GHz radar I built easily picked up tennis balls and
pedestrians' legs. I used earphones to listen to the Doppler shift.
The amplifier overboosted and squared low frequencies, making them
audible from the raspy harmonics.
jsw
Ken S. Tucker
> "flybywire" <ram...@ny.com> wrote innews:sWl5o.39258$hz1.23446@hurricane:
>
> > ah the De Havilland Mosquito
> >news:1f96d487-278a-43a6...@h17g2000pri.googlegroups.com...
> >> Is there any reason a light aircraft on a budget could not use
> >> plywood? It would seem an idea, mixing wood and composite
> >> construction. Indeed plywood is itself a composite material of layers
> >> of glue and of wood.
>
> >> The trick, of course, is working around the larger metal components.
>
> the Hughes Spruce Goose was made mostly of epoxy-laminated birch veneer.
> It was a very big airplane.I have a Wood Magazine article on it.
>
> I wonder about the moisture content of wood affecting the "stealth"
> characteristics of the laminate. also,I believe the carbon fiber used in
> stealth construction acts as an absorbent of radar energy. Not totally,but
> partial absorbtion.
>
> BTW,there's a company that is making a laminated wood 2 seater sports
> car.It uses a GM Northstar motor,was featured in Wood Magazine several
> years ago.
I read some time ago wooden bodies aren't street legal, due to fire
and splinter hazard, the design spec's for street legal cars are
quite tight, for alot of good Gremlin reasons.
Ken
Eunometic
Two reasons it would be of limited value on its own:
1 The wood would still reflect a tiny amount; this would be adaquete
for a radar to pick up a return though at reduce range. A 16 fold
reduction in reflection only halves detection range. If the radar is
capable of detecting say 1000km the detection range is still within
the radar horizon.
2 The wood on its own might not reflect as much radar as metal but it
will transmit some of it rather than absorb it all, there are
significant structures in an aircraft that will be detected; these are
quite angular and will give a good dispersions. EG mosquito had metal
props, metal undercarriage and metal fuel tanks.
The USAF built fiberglass aircraft in the 1960s and did find a big
reduction though not enough to make an light aircraft stealthy.
(I think sailplanes have corener reflectors to aid there detection by
air traffic control?)
3 reflections occur at the interfaces where two materials have
different properties of impedence: the impedence being the ratio of
permitivity of free space divided by the perubillity of free space
(about 377 ohms for air).
One way to absorbe a broad range of frequencies is to build a Juaman
(after Johannes Jauman ) absorber.
1 1/4 wave absorber 2.5cm thick will intensively absorbe micrwaves at
10cm and 2.5cm (effectively covering 3cm) as well as singificantly
around 5cm and 15cm with effects at 20cm. You have to progressively
build up the density of the graphite or semiconducting material by
layers of say more concentrated material or by paining etc.
This is one of the more effective materials Germans used on u-boat
snorkels.
The other way is to put absorbant materials in paint or rubber, eg
ferric oxides, alumumium disks etc. Also used on u-boats, it was less
effective but easier to make for 3 dimensioanl surfaces. Jauman
abosrbers like to be simple sheets or cylinders (snorkel tube but not
top)
The case of the Horten Ho 229 is interesting however. The plywood
was to be a structure as follows:
1 A thin veneer layer of plywood.
2 A second layer of plastic wood called "form holz" consisting of
glue, saw dust and graphite about 1 inch thick.
3 Another veneer of plywood.
The graphite, similar to the material used in tyres is the world first
nano-material and acts as a reinforcing.
However it is also clearly semi-conducting and would tend to absorb
the radar waves rather than reflect and transmit them.
The Ho 229 built by the National Geographic channel funded team at
Northrop was an extremely true copy of the Ho 229 prototypes likely
radar signature. The effects of metal in the Ho 229 were simulated
by the use of silver paint. (this was so conductive that the Northrop
technicians demonstrated it by placing multimeter probes an inch apart
on this paint and showing zero ohms resistance.)
While the Northrop team found a significant reduction in radar
reflection that would reduce detectionto a tactically usfull degree
this is not indicative of planed production Ho 229 radar signature.
The question of the Ho 229 stealth has not been settled!
The reason is that the Ho 229V1 and Ho 229V2 prototypes were
concentional plywood not the graphite impregnated formholze.
Production Ho 229 would have been scaled up in size about 10% and used
the formholze material.
Interestingly the FFO (Forschunginstitute Oberpfaffenhofen) at
Oberpfaffenhofen basically the Luftwaffe signals research
establishment had a far reaching stealth program. One of these was to
detect the enemy radar, amplify the signal and invert its phase and
retransmit it in order to cancel it. (this is so called active
stealth and is used these days) using klystrons. There was even a
plasma stealth work seeking to minimist the effect of ions in jet
exhaust.
This indates German radar scientists at the Luftwaffe had carefully
scrutinised the nature and physics of reflection and sought ways to
minimise returns. It wasn't just the German navy seeking mast head
stealth.
If you wanted to reduce the radar signatue of an prop aircraft then
replace the metal prop with wood or fiberglass. This is why Mosquitos
were not stealthy.
Eunometic
<keithnos...@kwillshaw.demon.co.uk> wrote:
> "Juergen Nieveler" <juergen.nieveler.nos...@arcor.de> wrote in message
Towards the end of the war the German Navy (Coastal Artillery) put a
magnetron (3cm?) onto a 7m Wurzburg (See Riesse) dish. They used a
spiral scan (could have been raster but definetly not conical). They
were able to watch, as in a black and white TV, an image of a life
boat being lowered from a ship against the backdrop of the ships hull
and figures getting into it.
Modern signal processing is pretty effective at detecting very small
signals or synthesising big antena.
Orval Fairbairn
<7bb7fe42-e6cb-4e3b...@i19g2000pro.googlegroups.com>,
Eunometic <euno...@yahoo.com.au> wrote:
In addition, interior metal parts, such as engines, wiring, pushrods,
control cables, landing gear, etc. have very high radar reflectivity.
Even wooden and composite propellers reflect significant radar energy
and would present difficulties to the idea.
As Eunometric stated above, one would have to absorb the radar energy,
rather than expect radar transparency to do the job.
--
Remove _'s from email address to talk to me.
Keith Willshaw
"Eunometic" <euno...@yahoo.com.au> wrote in message
news:d9f29eb0-eb45-4159...@y12g2000prb.googlegroups.com...
> On Aug 2, 8:40 am, "Keith Willshaw"
>>
>> In his non fiction book Glide Path Arthur C Clarke mentioned
>> that the centimetric radar they were testing could pick
>> out the rifles of the sentries and bicycle being ridden
>> down the dispersal track.
>
> Towards the end of the war the German Navy (Coastal Artillery) put a
> magnetron (3cm?) onto a 7m Wurzburg (See Riesse) dish. They used a
> spiral scan (could have been raster but definetly not conical). They
> were able to watch, as in a black and white TV, an image of a life
> boat being lowered from a ship against the backdrop of the ships hull
> and figures getting into it.
>
Cite please , the discrimination needed to pick out the
echoes from the lifeboat and figures from the echo
of the ship seems an unlikely capability in 1945.
I would also like to know which piece of Ocean this is
supposed to have happened on.
> Modern signal processing is pretty effective at detecting very small
> signals or synthesising big antena.
>
Signal processing involves carrying out operations on those signals
to produce useful data from them. This can involve filtering,
spectrum analysis, feature identification and analysis.
It does not in itself help in detecting small signals but may
help to pull out small fluctuations in a larger signal.
Synthetic aperture radar does indeed rely on processing
the returns from multiple radars or a single moving radar
source.
This was of course quite beyond German capability in 1945.
Keith
The Raven
news:1f96d487-278a-43a6...@h17g2000pri.googlegroups.com...
I think the non-natural composites will outlast and outperform plywood be
orders of magnitude.
Dean
snipped to save electrons......
> 1 A thin veneer layer of plywood.
> 2 A second layer of plastic wood called "form holz" consisting of
> glue, saw dust and graphite about 1 inch thick.
> 3 Another veneer of plywood.
>
> The graphite, similar to the material used in tyres is the world first
> nano-material and acts as a reinforcing.
>
> However it is also clearly semi-conducting and would tend to absorb
> the radar waves rather than reflect and transmit them.
>
> The question of the Ho 229 stealth has not been settled!
>
> The reason is that the Ho 229V1 and Ho 229V2 prototypes were
> concentional plywood not the graphite impregnated formholze.
> Production Ho 229 would have been scaled up in size about 10% and used
> the formholze material.
>
>
> If you wanted to reduce the radar signatue of an prop aircraft then
> replace the metal prop with wood or fiberglass. This is why Mosquitos
> were not stealthy.
The only similarity of graphite to the material used in tires (tyres
if you prefer ) is that they are both forms of carbon.
Graphite is a planar structure being almost 2-D. The material used in
tires is carbon black, an amorphous (no crystal structure) kind of
material. It is doubtful whether the material used by the Germans
qualifies as a nano-material. The purity of such material is very
much in doubt.
Dean
Dean
> "flybywire" <ram...@ny.com> wrote innews:sWl5o.39258$hz1.23446@hurricane:
>
> > ah the De Havilland Mosquito
> >news:1f96d487-278a-43a6...@h17g2000pri.googlegroups.com...
> >> Is there any reason a light aircraft on a budget could not use
> >> plywood? It would seem an idea, mixing wood and composite
> >> construction. Indeed plywood is itself a composite material of layers
> >> of glue and of wood.
>
> >> The trick, of course, is working around the larger metal components.
>
> the Hughes Spruce Goose was made mostly of epoxy-laminated birch veneer.
> It was a very big airplane.I have a Wood Magazine article on it.
>
> I wonder about the moisture content of wood affecting the "stealth"
> characteristics of the laminate. also,I believe the carbon fiber used in
> stealth construction acts as an absorbent of radar energy. Not totally,but
> partial absorbtion.
>
> BTW,there's a company that is making a laminated wood 2 seater sports
> car.It uses a GM Northstar motor,was featured in Wood Magazine several
> years ago.
>
> --
> Jim Yanik
> jyanik
> at
> localnet
> dot com
Actually, it was not epoxy. It was resorcinol which is a urea-
formaldehyde resin. This would be an environmental nightmare today
with the current restrictions on formaldehyde exposure.
Dean
Jim Wilkins
wrote:
> "Keith Willshaw" <keithnos...@kwillshaw.demon.co.uk> wrote:
> > In his non fiction book Glide Path Arthur C Clarke mentioned
> > that the centimetric radar they were testing could pick
> > out the rifles of the sentries and bicycle being ridden
> > down the dispersal track.
>
>
> However, ground radar, counterbattery radar etc. rarely get used for
> air surveilance...
>
> --
> Juergen Nieveler
American radar in 1942 could detect birds at over 50 miles, which
caused at least one invasion scare.
jsw
Keith Willshaw
"Juergen Nieveler" <juergen.nie...@arcor.de> wrote in message
news:Xns9DC9CF48ECA0...@nieveler.org...
> "Keith Willshaw" <keith...@kwillshaw.demon.co.uk> wrote:
>
>> In his non fiction book Glide Path Arthur C Clarke mentioned
>> that the centimetric radar they were testing could pick
>> out the rifles of the sentries and bicycle being ridden
>> down the dispersal track.
>
> Ground radar used for decades has that capability, too.
>
> However, ground radar, counterbattery radar etc. rarely get used for
> air surveilance...
>
>
> --
> Juergen Nieveler
>
The fact that ground radar is not used for air surveillance
would come as a shock to those who manned Chain Home in WW2
Keith
Dan
I wonder if he's referring to ground radar as used against ground
targets. The U.S. used it in Viet Nam.
Dan, U.S. Air Force, retired
WaltBJ
airborne in an F86D out of Naha AB, Okinawa, when our local GCI site
diverted me to check out a pop-up target some 40 miles south of them.
My E4 radar picked up the target at about 10 miles. I was amazed to
see it was a small flock of geese, 6 or 7of them, about 100 feet off
the ocean heading north for Japan.
Walt BJ
frank
> > to produce useful data from them. This can involve filtering,
> > spectrum analysis, feature identification and analysis.
>
> > It does not in itself help in detecting small signals but may
> > help to pull out small fluctuations in a larger signal.
>
> > Synthetic aperture radar does indeed rely on processing
> > the returns from multiple radars or a single moving radar
> > source.
>
> > This was of course quite beyond German capability in 1945.
>
> backscatter and whatnot out of the data if you try to use an air
> surveilance radar able to pick up something as small as a rifle?
>
> I'd guess (but don't know and don't have the clearance) that you'd
> start detecting birds - and at speeds that might even be higher than
> that of a glider...
>
> --
> Juergen Nieveler
You also cue on velocity. And switch if backscatter is too bad. Sneaky
suckers use different wavelengths, they'll get you somehow. If all
else fails, burn the sucker with higher output. And have lots of
friends in fighters as escort.
When JSTARS was first fielded in Desert Storm, they hadn't finished
all the testing that would determine say what various Soviet tanks
look like at what distance. Or how they could pick up movement. Still
worked well. We were doing this, weren't they just flight testing
that..?????.....and the second question would be, anybody know if it
works....??? They learned a lot as they went along. A lot was
processing so if something moved between scans, it was a target of
some sort. When you're looking for large convoys trying to scoot
North, that was helpful to a lot of the A-10 and other drivers. And
they could do that over massive areas.
No doubt AWACS is sort of similar.
Some toys are very, very sweet.
Gordon
> The Ho 229 built by the National Geographic channel funded team at
> Northrop was an extremely true copy of the Ho 229 prototypes likely
> radar signature.
I couldn't agree less. I spent about an hour under that particular
replica aircraft today -- have you ever seen it in person or examined
its structure?
Euno, there is _no_ way you could call it a copy, let alone an
"extremely true copy". It has minimal wood bracing and the only
substantial
substructure of metal in the entire "shape" is the pilot's seat. The
instruments aren't real, there are no fuel tanks, radios, MLG struts,
wheel hubs,
or any of the other things that would be required to even qualify as a
replica. Your statement is quite incorrect.
> The effects of metal in the Ho 229 were simulated
> by the use of silver paint. (this was so conductive that the Northrop
> technicians demonstrated it by placing multimeter probes an inch apart
> on this paint and showing zero ohms resistance.)
It is not the same - its a 'similation', so its not "an extremely true
copy" unless the German engineers used silver paint instead of
engines,
and rice crispies instead of oxygen tanks.
> While the Northrop team found a significant reduction in radar
> reflection that would reduce detection to a tactically usfull degree
> this is not indicative of planed production Ho 229 radar signature.
I think they made a lovely and visually accurate full-scale model, but
as for proving anything about the original aircraft's stealthiness, I
sincerely doubt that.
> The question of the Ho 229 stealth has not been settled!
certainly not by this high-quality model.
> The reason is that the Ho 229V1 and Ho 229V2 prototypes were
> concentional plywood not the graphite impregnated formholze.
> Production Ho 229 would have been scaled up in size about 10% and used
> the formholze material.
bar napkin stuff -- there was a lack of time and it ran out, so all of
this is moot. The "extremely true copy"
did not use the formholze material, so it would only be accurate at
copying the initial Versuchs airframes,
not the dreamware Production Ho 229.
> If you wanted to reduce the radar signatue of an prop aircraft then
> replace the metal prop with wood or fiberglass. This is why Mosquitos
> were not stealthy.
But for the same reason, they had inherent stealth from their use of
non-strategic materials as opposed to designed
stealth. German airmen tasked with hunting Mosquitos reported that
the difficulty was not that their targets had reduced
RCS which limited their radar's ability to detect the British
aircraft, it was their morale-destroying speed.
The fan blades on the Horten would have been far worse a radar
reflector than the blades of the Mosquito's Merlins --
I've done radar intercepts on both prop aircraft and jets and the
difference is incredible. The fan blades have to
be metal and there are dozens more than the prop blades, all
reflecting radar waves.
Roger Conroy
"Keith Willshaw" <keith...@kwillshaw.demon.co.uk> wrote in message
news:m026o.48717$pj7.9701@hurricane...
Jim Wilkins
> ...
>
> The fan blades on the Horten would have been far worse a radar
> reflector than the blades of the Mosquito's Merlins --
> I've done radar intercepts on both prop aircraft and jets and the
> difference is incredible. The fan blades have to
> be metal and there are dozens more than the prop blades, all
> reflecting radar waves.
I've heard you can ID the engine by the return from the fan blades.
jsw
Keith Willshaw
"Roger Conroy" <roger...@nospam.hotmail.com> wrote in message
news:i3bjsa$ss1$1...@news.eternal-september.org...
Well now the first problem is that Mr Nieveler didnt refer to
ground surveillance radar, simply ground radar
The second minor issue is the system Arthur C Clarke was describing
in Glide Path was the early GCA (Ground Controlled Approach) radar
used to detect and guide aircraft onto the runway.
Keith
JasiekS
Uzytkownik "Gordon" <Gor...@oldboldpilots.org> napisal w wiadomosci
news:fea56c56-9540-4c0f...@f6g2000pro.googlegroups.com...
[...]
> > If you wanted to reduce the radar signatue of an prop aircraft then
> > replace the metal prop with wood or fiberglass. This is why
Mosquitos
> > were not stealthy.
> But for the same reason, they had inherent stealth from their use of
> non-strategic materials as opposed to designed
> stealth. German airmen tasked with hunting Mosquitos reported that
> the difficulty was not that their targets had reduced
> RCS which limited their radar's ability to detect the British
> aircraft, it was their morale-destroying speed.
> The fan blades on the Horten would have been far worse a radar
> reflector than the blades of the Mosquito's Merlins --
> I've done radar intercepts on both prop aircraft and jets and the
> difference is incredible. The fan blades have to
> be metal and there are dozens more than the prop blades, all
> reflecting radar waves.
Gordon, don't you feel tired repeasting the same things to the same
persons? There was independent thread about supposed stealth of Ho 229.
It looks that Ho 229 became stealthy exactly in the same moment when
'stealth' became a buzzword.
--
JasiekS
Warsaw, Poland
Tinzinious Nicklefritz
wrote:
> "JasiekS" <jasieks.no.s...@please.poczta.onet.pl> wrote:
> > Gordon, don't you feel tired repeasting the same things to the same
> > persons? There was independent thread about supposed stealth of Ho 229.
> > It looks that Ho 229 became stealthy exactly in the same moment when
> > 'stealth' became a buzzword.
>
>
> Seriously, though, ISTR that somebody DID RCS tests with a Ho229, and
> especially the funny paint that had been developed especially for it.
>
> While not "stealthy" in the modern sense, it was claimed that this
> paint reduced RCS by 20% or so...
>
> --
> Juergen Nieveler
While interesting, it'd be even more interesting to see factual,
documented evidence this "paint" ever existed. This mystical paint is
not on the Ho229 at NASM Garber, neither on the center section, nor
the wing panels, though it's been determined that the outer panels
were obtained at a different location and were in fact static test
items.
What's more often claimed as the "stealth" ingrediant of the Ho229 is
the adhesive used in bonding the skins, which includes a modest amount
or charcoal dust. The interesting thing is about that is that the
addition of charcoal dust to urea-based adhesives was a fairly common
practice at the time and had, in fact, been patented. Not for its
"stealth" qualities, mind you, but as a weight saving/structural
additive, similar in concept to adding aggregate to concrete.
Sometimes a cigar is just a cigar.
Jim Wilkins
> On Aug 5, 2:54 pm, Juergen Nieveler <juergen.nieveler.nos...@arcor.de>
> wrote:
> > Seriously, though, ISTR that somebody DID RCS tests with a Ho229, and
> > especially the funny paint that had been developed especially for it.
>
> > While not "stealthy" in the modern sense, it was claimed that this
> > paint reduced RCS by 20% or so...
>
> > --
> > Juergen Nieveler
>
> While interesting, it'd be even more interesting to see factual,
> documented evidence this "paint" ever existed. This mystical paint is
> not on the Ho229 at NASM Garber, neither on the center section, nor
> the wing panels, though it's been determined that the outer panels
> were obtained at a different location and were in fact static test
> items.
http://www.ibiblio.org/hyperwar/USN/rep/ASW-51/ASW-14.html
Schnorchel radar absorbers are in section 14.3.3.
jsw
Jim Wilkins
> While interesting, it'd be even more interesting to see factual,
> documented evidence this "paint" ever existed. This mystical paint is
> not on the Ho229 at NASM Garber, neither on the center section, nor
> the wing panels, though it's been determined that the outer panels
> were obtained at a different location and were in fact static test
> items.
Plain old iron oxide, rust, such as was used in commercial Zeppelin
paint is a radar absorber.
jsw
Tinzinious Nicklefritz
>
> - Show quoted text -
Thanks, jw.
I've read descriptions of this "Schornsteinfeger" stuff applied to U
Boats before in postwar RN reports, and as I recall, it was a multi-
layered composition of some carbon-impregneted goop and rubberized
sheets of some sort of reflective material.
In any event, whatever it was, it most certainly *wasn't* "paint" in
any useful sense of the word as it applies to aviation. If anyone had
troweled enough of that glop on an Ho229 to be remotely effective,
it'd have taken an Me-323 with RATO packs and a half-inch steel cable
to drag the whole sodden mess off the ground.
Dan
Hindenburg's fabric was doped and painted with a mixture that was
flammable and accelerated by the hydrogen. The iron oxide layer was a UV
absorber. Radar wasn't a factor. The silver coloured exterior was to
reflect sunlight and heat to prevent the gas in the cells from expanding
and valving off.
Tinzinious Nicklefritz
As true as that may be, you still have to combine all that rust with
some sort of binder to get it to stick to the surface in question.
Both of those components carry a significant weight penalty. It's
problematic to make any assumptions about what and how much in absence
of any hard evidence the stuff existed.
IOW, for all their fanatical devotion to documenting their ideas - the
aforementioned "Schornsteinfeger," for example, why is it we never
hear a peep about this marvelous Nazi paint until nearly 40 years
after the fact?
I've spoken with the people at Garber about this very topic, and
they've replied that their 229 is covered with the barest coat of drab
green necessary to cover the wood.
I'd settle for a documented name for the stuff - at least that would
be someplace to start looking.
Jim Wilkins
> aforementioned "Schornsteinfeger," for example, why is it we never
> hear a peep about this marvelous Nazi paint until nearly 40 years
> after the fact?
Apparently Schornsteinfeger was a generic name for the program.
Literally it means Chimney Sweep, and refers to carbon black (soot)
Perhaps this is too technical, Smith charts and all, but there is some
qualitative description of Jaumann absorbers:
http://www.microwaves101.com/encyclopedia/absorbingradar3.cfm
Lambda is wavelength, 377 Ohms is the impedance (ratio of electric E
to magnetic H field intensity) of free space.
The H field is at a right angle to the E field and 1/4 wave out of
phase and the total energy alternates between them without loss, sin^2
X + cos^2 X = 1. That's why the first diagram shows red arrows across
the page for E and the points and feathers of arrows in and out of the
page for H.
Wakarimaska?
jsw
Tinzinious Nicklefritz
>
> Wakarimaska?
>
> jsw
nihongo ga.
Obviously, the disconnect here is that I'm not asking for a
comprehensive lecture on the technology in latter-day form; I'm asking
for simple proof the Nazis had anything even in the parking lot, much
less the ball park.
That is what's conspicously missing. ;)
Jim Wilkins
> On Aug 5, 9:18 pm, Jim Wilkins <kb1...@gmail.com> wrote:
> Obviously, the disconnect here is that I'm not asking for a
> comprehensive lecture on the technology in latter-day form; I'm asking
> for simple proof the Nazis had anything even in the parking lot, much
> less the ball park.
>
> That is what's conspicously missing. ;)
Not missing, just not whack-upside-the-head obvious. The article
describes how the Jaumann and Wesch types of radar absorbers as used
on U-Boot Schnorchels work, so yes they had them, as did the Allies. I
don't know about the Horten flying wings, the owner of the borrowed
book I had on them took it back.
jsw
Orval Fairbairn
Dan <B24...@aol.com> wrote:
The silver-colored paint is still used in dope & fabric aircraft
coverings -- to reflect UV rays from the sun. You spray it on until a
light bulb held on the other side cannot transmit light through it.
It is simply aluminum powder mixed with clear dope.
--
Remove _'s from email address to talk to me.
Steve Hix
<o_r_fairbairn-FBA...@70-3-168-216.pools.spcsdns.net>,
Orval Fairbairn <o_r_fairbairn@earth_link.net> wrote:
> In article <NqCdnf_q64DHyMbR...@giganews.com>,
> Dan <B24...@aol.com> wrote:
>
> > Jim Wilkins wrote:
> > > On Aug 5, 3:25 pm, Tinzinious Nicklefritz <1978...@gmail.com> wrote:
> > >> ...
> > >> While interesting, it'd be even more interesting to see factual,
> > >> documented evidence this "paint" ever existed. This mystical paint is
> > >> not on the Ho229 at NASM Garber, neither on the center section, nor
> > >> the wing panels, though it's been determined that the outer panels
> > >> were obtained at a different location and were in fact static test
> > >> items.
> > >
> > > Plain old iron oxide, rust, such as was used in commercial Zeppelin
> > > paint is a radar absorber.
> > >
> > > jsw
> >
> > Hindenburg's fabric was doped and painted with a mixture that was
> > flammable and accelerated by the hydrogen. The iron oxide layer was a UV
> > absorber. Radar wasn't a factor. The silver coloured exterior was to
> > reflect sunlight and heat to prevent the gas in the cells from expanding
> > and valving off.
>
> The silver-colored paint is still used in dope & fabric aircraft
> coverings -- to reflect UV rays from the sun. You spray it on until a
> light bulb held on the other side cannot transmit light through it.
Say ... aluminum powder and iron oxide. Mix together, add heat...
Jim Wilkins
> ...
> Say ... aluminum powder and iron oxide. Mix together, add heat...
It's very difficult to ignite because the aluminum quickly becomes
covered with a highly refractory (heat resistant) oxide coating. When
you melt small pieces to make a casting it's hard to get the liquid
metal to separate from the oxide and pool together.
The chips that accumulate around machine tools are potentially a
thermite hazard too, but in practice only sanding dust seems to be a
slight problem and then only if the machine isn't cleaned after use. I
don't use water-based coolant on my lathe or mill so the steel chips
don't rust.
Even magnesium is difficult to light. I placed a small chunk on
glowing charcoal in a woodstove and watched it melt first.
jsw
Tinzinious Nicklefritz
wrote:
> Somebody at Northrop-Grumman might know - found the story, they built a
> static 1:1 model of the Ho229 using the old plans and materials:
>
> http://www.foxnews.com/story/0,2933,529548,00.html
>
> --
> Juergen Nieveler
Hi Juergen,
Actually, a good source on that particular mockup would be this very
own group's Gordon - it was donated to his museum. He's made mention
of looking at it up close at least once that I recall.
While bouncing about the net, going over old info on the "Formholtz"
plywood bomding process, I came across this forum discussion of the
very topic:
http://www.homebuiltairplanes.com/forums/warbirds-warbird-replicas/5255-horton-wings-3.html
Some excerpts:
[begin quotes]
regarding the mockup:
Yes, the radar range test showed a 20% reduction in the return signal
over what bare metal would have returned. As you saw in the slide show
the mockup is entirely made of plywood but what it didn't show was
that the metal parts were simulated with some very expensive silver
paint on the inside of the skin. The turbine blades were made from
sintered nylon fused together by a neat 3D printing proses then
painted with silver. The cockpit details were made of plastic and also
painted with the reflective paint then painted the appropriate colors.
So it did have the materials simulated if not actually there. That 20%
reduction was from the 17mm thick leading edge absorbing some of the
reflection from the fuel tanks. The false color display of the
analysis showed that in spite of having to pass through the thick skin
twice there was still a detectable signal from the wings and, of
course, the nose lit up like a cristmas tree. I was really
disappointed. The technical stuff s only about 10 minutes, the rest of
the show is almost entirely devoted to David Myhra's fantasies
"stealth" as a design parameter:
In our book "Horten 229, Spirit of Thuringia" by Classic Publications
2006 we (Andrei Shepelev and Huib Ottens) have given our conclusions
regarding the "stealthyness" of the Ho 229 in the last chapter
"Invisible Legacy".
As part of our research I have spent 3 days with Professor Karl
Nickel (sadly passed away this year) and his wife (the sister of
Walter and Reimar Horten). Both were directly involved in the
development of the H IX / Ho229 and other Horten flying wings.
During our conversations the stealth subject was discussed. Karl
Nickel clearly stated that stealth was not a design-parameter for the
H IX/Ho229. The use of wood as the main construction material and the
flying wing shape of the aircraft just followed the design and
construction philosophy of the Horten brothers, as displayed in their
line of flying wing designs that started in 1933 with the Horten H I.
The carbon or charcoal-glue mixture was only used as porous filler to
lighten the composite formed parts.
So our conclusion is and remains that all the stealth-characteristics
of the Ho229 are purely accidental, despite all post-war statements
made by Reimar Horten and all the attempts to rewrite the Ho229
history. I just wonder: Is the concept, design, development,
construction and testing of an all-wing, jet-engined fighter-aircraft
in the WW II era not revolutionary and astonishing enough?
Reimar's later claims:
So Reimar was making the stealth claim as early as 1982...
Which, not cooincidentally, was shortly after the first reports of
'stealth' technology started leaking out into the media, such as
Aviation Week. I even remember carbon being listed as "likely being
used" as part of RAM then.
Interestingly, I just cracked "...Thuringia" and on page 116, column
1, paragraph 2, (italics the authors, underline mine for emphasis of
the point):
"Although the Ho229 has been immediately identified as "stealthy" due
the the characteristics of its overall configuration, neither of the
Horten brothers ever claimed their aircraft had been designed with
consideration to the way it deflects radar waves. In fact, the unique
shape of the Ho 229 had evolved from the ten-year long aerodynamic
research done by the Hortens. What Reimar did claim as far back as
1950, was that the wooden construction of the Ho 229 would reflect
very little of the incoming electromagnetic waves, thus making the
aircraft "...barely visible on the radar"."
I pulled that particular quote because, in light of Reimar's later
assertions regarding the carbon in the Formholz wing-skin material,
it's quite obvious that he actually had little or no knowledge of how
'stealth' works, and was 'making this up as he went along.' He
certainly wasn't asserting that Formholz was radar-absorbant in the
1950's, when he was saying that the aircraft would be less visible on
radar because of its "wooden structure" would reflect less radar.
Conventional wooden structure is transparent to radar, which only
means that any metal structure or parts beneath the skins are
completely open to the incoming beam, and can, quite nicely, reflect
the beam back all on their own. Brackets, belcranks, and the like are
outstanding radar reflectors - more so than a smooth metal surface
skin, properly joined mechanically and electrically. And again, no use
was made of the existing RAM materials known to the German military at
the time, especially on the metal-skinned inlet housings and other
metal parts of the aircraft.
I suspect that this is a case of Reimar "adding on features" as we
discussed earlier, and then the media and people like Myhra running
with a passing mention of Reimar's on the subject and blowing it out
of proportion.
Myhra is an odd character. I have a few of his books (booklets?) -
He-162, Bv-141, Ba 349 Natter, Me-263, for example. He's been very
good about finding (or at least publishing) quite a few photos and
original drawings that quite simply can't be found in other sources,
but then he goes off into fantasyland about "what if.." scenarios, and
tends to exaggerate or distort facts, as seems to be the case with the
"Stealthy" Ho 229. I've ended up purchasing his books for the original
drawings and photos, and pretty much ignoring the rest of the
material.
Thanks for the additional material. It's great, not only to help clear
up the misinformation, but also to keep word flowing about this
amazing airplane. It's a shame the one at the NASM has been so
neglected, but if, as appears from the gentleman you're quoting above,
the aircraft on-hand is incomplete and/or not completely original work
by the Hortens, I can somewhat understand why it's been placed lower
on the priority list than other, more complete, aircraft.
--------------------------------------------------------------------------------
[end quotes]
And so on and so forth.
No mention of this mythical "paint" to be found.
Tinzinious Nicklefritz
wrote:
> Tinzinious Nicklefritz <1978...@gmail.com> wrote:
> > On Aug 6, 2:03 pm, Juergen Nieveler <juergen.nieveler.nos...@arcor.de>
> > wrote:
>
> >> Somebody at Northrop-Grumman might know - found the story, they built
> >> a static 1:1 model of the Ho229 using the old plans and materials:
>
> >>http://www.foxnews.com/story/0,2933,529548,00.html
>
>
> > No mention of this mythical "paint" to be found.
>
>
> --
> Juergen Nieveler
Unfortunately, it would seem so.
I've pretty well come to the conclusion that somebody, somewhere heard
about the carbon component of the plywood bonding process mentioned as
a "stealth" feature, mis-remembered or mis-represented it somewhere as
"paint" and viola, an urban legend was born.
David E. Powell
wrote:
> Tinzinious Nicklefritz <1978...@gmail.com> wrote:
> > I've spoken with the people at Garber about this very topic, and
> > they've replied that their 229 is covered with the barest coat of drab
> > green necessary to cover the wood.
>
> > I'd settle for a documented name for the stuff - at least that would
> > be someplace to start looking.
>
> static 1:1 model of the Ho229 using the old plans and materials:
>
> http://www.foxnews.com/story/0,2933,529548,00.html
>
> Juergen Nieveler
I believe there is a comment upthread about this form a guy who was
there and got a good look at the model, about the things it got right,
etc...
Gordon, actually. here's the link:
http://groups.google.com/group/rec.aviation.military/msg/41eb149222f9a37b
<http://groups.google.com/group/rec.aviation.military/msg/
41eb149222f9a37b>
Dave
Scott M. Kozel
Burning hydrogen is hot enough to easily ignite any of those
materials.
Steve Hix
Jim Wilkins <kb1...@gmail.com> wrote:
> On Aug 6, 12:39 am, Steve Hix <se...@NOSPAMmac.comINVALID> wrote:
> > ...
> > Say ... aluminum powder and iron oxide. Mix together, add heat...
>
> It's very difficult to ignite because the aluminum quickly becomes
> covered with a highly refractory (heat resistant) oxide coating.
I know, I've worked with thermite.
> When
> you melt small pieces to make a casting it's hard to get the liquid
> metal to separate from the oxide and pool together.
>
> The chips that accumulate around machine tools are potentially a
> thermite hazard too, but in practice only sanding dust seems to be a
> slight problem and then only if the machine isn't cleaned after use. I
> don't use water-based coolant on my lathe or mill so the steel chips
> don't rust.
>
> Even magnesium is difficult to light. I placed a small chunk on
> glowing charcoal in a woodstove and watched it melt first.
I don't recall ever seeing magnesium light off before melting. But I never
handled large pieces that way.
Didn't want to, frankly, having heard some stories of industrial magnesium fires
from my father.
Dean
> In article <59934bc9-f9a2-4d55-9e58-461624508...@5g2000yqz.googlegroups.com>,
Magnesium not only will not light off as a solid, it won't light off
as a liquid either. It needs to vaporize. But that's just a minor
quibble.
I once saw a 2" x 2" x 4 ' bar of magnesium ignite while being
machined. The operator unclamped it, took hold of one end and ran out
the door to the Susquehanna River right out back. He tossed it in and
the explosion was spectacular! The end result was better procedures
and more education on how to control a magnesium fire.
Dean
Dan
I would have liked to have seen that. I would also have liked to have
seen the expression on his face.
Orval Fairbairn
Dan <B24...@aol.com> wrote:
An old friend, who worked in WW-II at the Stinson factory in Nashville,
used to tell shop stories of throwing a small piece of mag into a bucket
of water, lighting it with an oxy/acetelyene torch and watching it burn
under water.
Dan
A small piece of sodium dropped into water will ignite and skate
across the surface. A large piece makes a mess and is very dangerous.
Steve Hix
Juergen Nieveler <juergen.nie...@arcor.de> wrote:
> Dean <dama...@gmail.com> wrote:
>
> > Magnesium not only will not light off as a solid, it won't light off
> > as a liquid either. It needs to vaporize. But that's just a minor
> > quibble.
>
> Our chemistry teacher used a strip of magnesium tape to light off some
> Thermite... how did that work, then?
If you watch the end of the tape, you'd see it glow red briefly, then sag as it
melted just before it lit off.
If it needed to vaporize to ignite, not much of it was needed, the rest would
follow quickly.
> Not doubting you, just curious on the mechanics involved - did the
> flame of the bunsen burner he used heat the magnesium sufficiently to
> vaporise?
Steve Hix
Dan <B24...@aol.com> wrote:
>
> A small piece of sodium dropped into water will ignite and skate
> across the surface. A large piece makes a mess and is very dangerous.
Put a peanut-size chunk in a plastic pill bottle, cap it and punch a hole in the
cap. (Pure sodium ought to be stored in oil, and it's about as hard to cut as a
firm cheese.)
Toss it into a ditch filled with water. Sometimes you need to throw rocks at the
floating bottle to sink it, or at least get enough water in to sink it.
A bit of hissing, followed by a geyser, and bits of sodium skating around the
ditch.
I've watched it done. Really. It wasn't my idea. Honest.
Potassium metal is even more energetic; they never let us experiment with
lithium.
Eunometic
wrote:
> Uzytkownik "Gordon" <Gor...@oldboldpilots.org> napisal w wiadomoscinews:fea56c56-9540-4c0f...@f6g2000pro.googlegroups.com...
>
> [...]
>
>
>
>
>
> > > If you wanted to reduce the radar signatue of an prop aircraft then
> > > replace the metal prop with wood or fiberglass. This is why
> Mosquitos
> > > were not stealthy.
> > But for the same reason, they had inherent stealth from their use of
> > non-strategic materials as opposed to designed
> > stealth. German airmen tasked with hunting Mosquitos reported that
> > the difficulty was not that their targets had reduced
> > RCS which limited their radar's ability to detect the British
> > aircraft, it was their morale-destroying speed.
> > The fan blades on the Horten would have been far worse a radar
> > reflector than the blades of the Mosquito's Merlins --
> > I've done radar intercepts on both prop aircraft and jets and the
> > difference is incredible. The fan blades have to
> > be metal and there are dozens more than the prop blades, all
> > reflecting radar waves.
>
> Gordon, don't you feel tired repeasting the same things to the same
> persons? There was independent thread about supposed stealth of Ho 229.
> It looks that Ho 229 became stealthy exactly in the same moment when
> 'stealth' became a buzzword.
Horten was talking of stealth in 1950. I'll quote from a speech he
gave below.
Quoting a fictional "usenet thread" is about as non credible as it
is possible to get.
WW2 Germans did 'invent' stealth.
>
> --
> JasiekS
> Warsaw, Poland- Hide quoted text -
Rainer Horten gave a talk in Argentina in 1950 before the "Revista
Nacional de Aeronautica" where touted the importance of "Radar
Camaflage". Its on the record.
He spoke about it several times but he was so far ahead of his time
that most people were clearly unable to comprehend. Many still
can't.
The German navy had a very far reaching stealth program and applied
radar absorbant materials (rubbers laoded with ferritic absorbers) as
well as "Jauman absorbers" to the mastheads of their U-boats. The
Luftwaffes FFO establishment was working on a number of Stealth
techniques.
"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."
Flying Wing Fighter "Horten IX"
by Doctor Reimar Horten
(as translated by: Fernando Walter Siarez, Buenos Aires, Argentina)
(The original article was titled "Ala volante Caza 'Horten IX' ", by
Dr. Reimar Horten, published by Revista Nacional de Aeronautica,
(today: Aeroespacio, Revista Nacional Aeronautica y Espacial) " May
1950, number 5, pages 19-20; Buenos Aires, Argentina. We thank them
for allowing the translation and publication here for all to share.
The article is being provided in both English and Spanish.)
The performances and qualities a modern fighter must have are very
varied. In peacetime, the fighter development is always oriented
towards its maximum speed, despite that there are many performances
and qualities that determine its value during combat missions.
If the fighter is 100 Kilometers/hour [about 60-mph -Trans] faster
than the bomber plane, it can overtake this latter and absolute speed
is a secondary subject. During combat between fighters, higher speed
is an advantage, as is higher climb rate and higher ceiling. Turning
radius or time for a complete turn, are other performances that are
not less important, to mention some of them.
To avoid combat, maximum speed is the only decisive one, but this is
not the mission of a fighter. To intercept and achieve air supremacy,
it is advantageous the higher starting position. If surprise factor
fails, combat transforms into a "turning" combat. To be able to fly
with small diameter turns, low wing loading is needed, from which a
big wing results, what is advantageous for the practical ceiling. With
this wing, take off and landing speeds, mainly the latter, are kept in
an easy to dominate envelope and the amount of fuel carried aboard -
that in jet aircraft can never be sufficiently large- allows
satisfactory range values. The big wing does not decrease largely the
maximum speed in jet fighters, because that is influenced only by
aerodynamic design. This phenomenon comes from the fact that at such
velocities, sonic speed is frequently achieved, so getting big
additional drags. So, for example, the swept wing provides a mean to
delay this drag increase, to much higher speeds.
Other factors of equal importance as speed, ceiling and turning radius
also determine the combat value of a fighter. To describe them all
will take us too far and is out of the scope of this article. 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.
A fighter must use the surprise factor, especially at night; to do
that, the plane must be built in wood, not only for the above
mentioned circumstance, but also because the wood surface resistance
to impacts is not necessary inferior to that of metallic surfaces, as
was shown by tests. Also, those resistances are regarded of secondary
importance, because with modern big gage guns, an impact means
practically a total loss.
As far as landing speed is concerned, I want to say some words,
because very often it is given a secondary importance: personally, I
consider it very important because "cold losses" depend on it. Any
loss is a victory for enemy. So, landing speed has great importance,
besides the fact that it determines service possibilities in bad
weather and at night. On the other hand, a pilot that has just ended a
combat cannot be asked for high skill performances, needed with high
landing speeds. Another point deserving mention, is that practice
demonstrated that during a war, type specialization cannot be kept:
the fighter drops bombs, takes part in ground combats, makes night
interception and reconnaissance flights. Technology would like to
solve a specific problem; anyway, it has to design the fighter as a
multi-role aircraft and accept many compromises in such a way, that it
must be able to carry bombs, or supplementary droppable tanks when it
flies in a defensive mission; it must also be able to launch rockets,
or be provided with an automatic movie camera, etc.
Guided by these thoughts, I built in 1943 the Horten IX model, from
which two prototypes were built in the own firm, passing in 1944 to
series construction under the license Gotha-Waggon Gotha. It is a
flying wing of 16 meters span, equipped with two Junkers 004 turbine
engines, built in three parts, the central wing section and two
exterior parts. The central part that bears the load is 3.2 meters
[10.5 ft -Trans] long and is built in steel tubing; in it the landing
gear, turbines, weapons and pilot seat are fixed.
The turbines are inside the wing and receive air from the leading
edge, without deflections. The cabin is put in the vertex of the sweep
angle, between both motors, and is equipped with ejector seat, so as
to allow the pilot to descend in parachute, without risk, at high
flying speeds; besides the necessary armor, it has radio and
identification instruments. Four MK 103 cannons, 30 mm gage, of 900 m/
s of initial speed that produce a noticeable effect on the target and
a ballistic corresponding to flight speeds. It has a hanging device
for two bombs of 1000 Kilograms each, or for two droppable
supplementary tanks, also of 1000 kilograms each. Its range is of 4000
Kilometers with 2400 kilograms of fuel in the wing, but it could be
extended considering the very improved fuel consumption of today.
The landing gear, with nose wheel, had been designed for the
aggravated conditions of night flying and was retractable to the wing
center section. In spite of the low landing speed, of 140 kilometers
per hour [87 mph -Trans], a detachable drag parachute had been
installed, which allowed very short landing runs. In the center
section also is installed a aerodynamic brake that permits a rapid
adjust of the own speed to the enemy's own one, and that can be also
used for landing. The cover shells are wood "monocoque" parts, easy to
dismount for maintenance of the engines [and of ] the weapons. The
second model was a two place one for night flights and training. The
outer wing parts, completely built in wood, are of single spar
construction. The leading edge is built in shaped wood, this is,
milled wood, mixed with adhesive and then pressed to the definitive
shape. By means of this construction method, a high quality product of
any shape and size, can be made. The spar that transmits the forces
from the wing fitting to the "monocoque", houses in its interior the
command push rods. All wing space must be filled with fuel, using very
simple rubber bags, attached to the monocoque. The rudders, mounted as
brakes at the wing tips, produce a safe effect at any speed, and -by
means of some manipulations- can also serve as elevators, so as to
assure, even in supersonic flight (it can happen in a down pitch)
total dominion of the plane.
After five years have passed since the last construction in Germany, I
can demonstrate that the Horten IX has not been surpassed by more
recent constructions. Speed records are, today as yesterday, over 960
Kilometers an hour [596 mph -Trans], its maximum speed, but the
general design combination has not been excelled. The fact is that the
construction principles should have been guided only by the physical
phenomena arising from experiments with other built airplanes, without
copying them. The contrast to this is the conventionally built
airplane, resulting from the average of several ones, to be built
Keith Willshaw
"Eunometic" <euno...@yahoo.com.au> wrote in message
news:86df1c44-c792-4198...@x18g2000pro.googlegroups.com...
Its a pity as he was talking complete bollocks.
The German radars of WW2 had no problem seeing wooden
aircraft such as the Mosquito,
The thing you have to recall about Reimar Horten is that he
was giving a sales pitch but the bottom line is that he was
basically a glider designer and never had a combat
aircraft enter production let alone service. He was
certainly no radar expert.
The reality is any service aircraft contains enough reflective
material to return a whacking great radar return even if
the airframe was transparent to radar. Start with two
whacking great engines add the cannon, oxygen bottles,
control cables, radios, batteries etc and you have something
that any 1945 radar can pick out with ease.
The 'success' of the stealth program of the German Navy may be
best measured by its loss and success rates.
Year Losses Sinkings
1939 2 167
1940 24 564
1941 35 500
1942 86 1321
1943 243 579
1944 249 246
1945 120 99 - in 5 months
By 1945 Germany was losing more U-boats than the
allies were ships and since a U-boat typically
went down with all hands the loss of crews was
far worse.
Keith
Eunometic
> On Aug 1, 5:57 pm, Eunometic <eunome...@yahoo.com.au> wrote:
>
> > The Ho 229 built by the National Geographic channel funded team at
> > Northrop was an extremely true copy of the Ho 229 prototypes likely
> > radar signature.
>
> I couldn't agree less. I spent about an hour under that particular
> replica aircraft today -- have you ever seen it in person or examined
> its structure?
> Euno, there is _no_ way you could call it a copy, let alone an
> "extremely true copy". It has minimal wood bracing and the only
> substantial
> substructure of metal in the entire "shape" is the pilot's seat. The
> instruments aren't real, there are no fuel tanks, radios, MLG struts,
> wheel hubs,
> or any of the other things that would be required to even qualify as a
> replica. Your statement is quite incorrect.
>
You're on the record as claiming that the Horten replica is not good a
valid simulation of the Horten 229. Your agenda seems to be to deny
the possibility that the Hortens and/or Germans were working towards
airborn stealh in ww2.
In fact there is a lot of proof for that. There is the German Navy
program, kicked of with a conference of 400 engineers, scientists,
strategists etc in 1943. Then there is the Luftwaffe's FFO stealth
program. It's clear the Germans were thinking of stealth at sea, in
the air and on the ground.
First of all let me note what the Northrop folks insisted upon this as
being a valid way of getting a first order approximation of RCS. I
note they are experts and experience in the area of simulating stealth
you arew not.
1 They simulated the first stage compressor with metalased plates
fabricated to look like engine inlet compressors, the engines with
metal tubes of demensions similar dimensions to the Jumo.
2 The internal metalic structure of the fuel tanks and metalic tube
structure around the engines was simulated with silver paint.
To a radar silver paint and an actual metalic rube or plate would look
much the same.
The internal wood bracing is close to irrelevant.
Gordon. did you even bother to watch the NG special?
You might be able to look at that machine but you do not seem to
comprehend that you would not see the silver conductive paint.
Nor do you mention the conductive instrument binacle, seat, jet tubes,
inlet compressor face, simulated tanks etc. You do mention the seat.
> > The effects of metal in the Ho 229 were simulated
> > by the use of silver paint. (this was so conductive that the Northrop
> > technicians demonstrated it by placing multimeter probes an inch apart
> > on this paint and showing zero ohms resistance.)
>
> It is not the same - its a 'similation', so its not "an extremely true
> copy" unless the German engineers used silver paint instead of
> engines, and rice crispies instead of oxygen tanks.
A strip of silver paint looks much the same as a metal strip of tube
of the same length and dimension.
>
> > While the Northrop team found a significant reduction in radar
> > reflection that would reduce detection to a tactically usfull degree
> > this is not indicative of planed production Ho 229 radar signature.
>
> I think they made a lovely and visually accurate full-scale model, but
> as for proving anything about the original aircraft's stealthiness, I
> sincerely doubt that.
The flying wing, propellorless as it is, clearly has advantages.
>
> > The question of the Ho 229 stealth has not been settled!
>
> certainly not by this high-quality model.
>
> > The reason is that the Ho 229V1 and Ho 229V2 prototypes were
> > concentionalplywoodnot the graphite impregnated formholze.
> > Production Ho 229 would have been scaled up in size about 10% and used
> > the formholze material.
>
> bar napkin stuff -- there was a lack of time and it ran out, so all of
> this is moot. The "extremely true copy"
> did not use the formholze material, so it would only be accurate at
> copying the initial Versuchs airframes,
> not the dreamware Production Ho 229.
>
> > If you wanted to reduce the radar signatue of an prop aircraft then
> > replace the metal prop with wood or fiberglass. This is why Mosquitos
> > were not stealthy.
>
> But for the same reason, they had inherent stealth from their use of
> non-strategic materials as opposed to designed
> stealth.
The fact that there are many of the shelf duel use materials hadn't
entered into your thoughts?
> German airmen tasked with hunting Mosquitos reported that
> the difficulty was not that their targets had reduced
> RCS which limited their radar's ability to detect the British
> aircraft, it was their morale-destroying speed.
Interesting but irrelevant.
>
> The fan blades on the Horten would have been far worse a radar
> reflector than the blades of the Mosquito's Merlins --
> I've done radar intercepts on both prop aircraft and jets and the
> difference is incredible. The fan blades have to
> be metal and there are dozens more than the prop blades, all
> reflecting radar waves.
This claim of yours goes against all the text books. A medium sized
tactical jet such as a T-38 or F5 would have a smaller RCS than a
single engined light plane.
Have a look at a Jumo 004. Compare the nose cone to the size of the
prop hub on a Merlin or R-2800.
Have a look at a P-2800 and its row of two cylinders and compare it to
the inlet dimensions of a Jumo 004. Compare even the radiator scoop
on a mustang or Lancaster and compare it to the small inlet of the
Jumo 004.
Here are the RCS published in Dorf's "The Electrical Engineering
Handbook" for
the following frequency ranges:
Frequency range: 1-2Ghz, 3GHz, 5GHz,
Small Propellor : 2.0 , 3, , 2.5
LearJet : 1.0 , 1.5 , 1.0
T38 : 2.0 , 2-3 , 2
T39 : 2.5 ,? ,8
F4 : 5-8, , 4-20, 4
Standing Man : 0.3, ,0.5, 0.6
Note a small propellor aircraft such as a piper had larger RCS than a
Learjet or T-38/F5.
Much work was done in the 1950s by Skolnik. RCS varied from 30 to
25db (relative to 1m^2) so about 10-50 rcs m^2 depending on viewing
angle.
http://www.radartutorial.eu/18.explanations/ex09.en.html
Propellor angle modulated the strenght of the signal by as much as
10:1
http://books.google.com.au/books?id=qZlrReU-cMkC&pg=PT28&lpg=PT28&dq=radar+cross+section+propellor&source=bl&ots=NrbWeLW8Sh&sig=jI6tL5chPlCW6VMrhAt1aNwu0yY&hl=en&ei=YX9eTIvtJ8yecdjUiNoO&sa=X&oi=book_result&ct=result&resnum=10&ved=0CEsQ6AEwCQ#v=onepage&q&f=false
http://www.radartutorial.eu/18.explanations/ex09.en.html
I don't doubt that of viewed from a favourable angle, eg directly down
the inlet, at a wavelenth twice that of inlet guide vanes there may be
a strong reflection.
My problem with the Northrop/NG simulation is that it did not simulate
the graphite impregnated formholze of the production versions.
The smooth semiconducting material would have absobed internal
reflections and also due to the smooth interuption free nature of the
wood there would be no surface wave reflections where sheets of
aluminium were joined
Note, the Me 163 was probably the stealthiest aircraft of WW2. No
prop, no radiator or engine inlet and made of wood and no tail plane.
Eunometic
wrote:
> "JasiekS" <jasieks.no.s...@please.poczta.onet.pl> wrote:
> > Gordon, don't you feel tired repeasting the same things to the same
> > persons? There was independent thread about supposed stealth of Ho 229.
> > It looks that Ho 229 became stealthy exactly in the same moment when
> > 'stealth' became a buzzword.
>
>
> Seriously, though, ISTR that somebody DID RCS tests with a Ho229, and
> especially the funny paint that had been developed especially for it.
>
> While not "stealthy" in the modern sense, it was claimed that this
> paint reduced RCS by 20% or so...
Reduced RCS to 40% of that of an Me 109 which reduced detection range
by 20%.
This aircraft lacked the formholz of the production versions.
Eunometic
> On Aug 5, 2:54 pm, Juergen Nieveler <juergen.nieveler.nos...@arcor.de>
> wrote:
>
>
> What's more often claimed as the "stealth" ingrediant of the Ho229 is
> the adhesive used in bonding the skins, which includes a modest amount
> or charcoal dust. The interesting thing is about that is that the
> addition of charcoal dust to urea-based adhesives was a fairly common
> practice at the time and had, in fact, been patented. Not for its
> "stealth" qualities, mind you, but as a weight saving/structural
> additive, similar in concept to adding aggregate to concrete.
Duel use material. Its clear that the hortens would have been
improvising. They ran a small jobing shop, had no wind tunnels etc.
The Hortens lost their 3rd brother who was laying mines at night in a
He 111. I expect he was intercepted by radar. Loosing ones brother
tends to concentrate ones mind.
I have photographs of Me 109 models (Trenkle) the German used to take
RCS measurments. One would think that someone might come across the
thought that perhaps this could be minimised.
Peter Skelton
Bullshit. Grog invented it when he tiptoed up to Hrin before
clinking him on the nogging with an antelope thigh-bone and
taking him home for dinner.
More seriuously, stealth as a concept with successful examples
predates human beings by millions of years. Examples are
uncountable (not incountable Fred,)
Peter Skelton
Tinzinious Nicklefritz
We keep hearing that - the "duel use" claim - from people determined
to make a silk purse from an historical sow's ear.
Strangely enough, there's no mention of this dual purpose of formholtz
to be found in Nurflügel - Die Geschicte der Horten-Flugzeuge
1933-1960 ( Reimar Horten and Peter Selinger, 1983), which has a
fairly good description of the materials.
Reimar's comments in the quoted 1950 speech have essentially nothing
to do with "stealth."
"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. "
http://www.twitt.org/Horten_May_50.html
Wood structures, pure and simple. No secret to anybody, even in 1950.
No mention of absorbants or other materials, no mention of any other
procedures designed to achieve the holistic solution that later became
known as "stealth."
It's already been discussed to death that regardless of the D-tube
skinning, the 229 would have stood out like a carbon arc searchlight
to common WWII Allied radar, especially from the forward quarters.
It's believable that that the Hortens were working on a shoestring
with a bare minumum of backing - they said as much themselves many
times. It's believeable that they worked with what they knew best -
wood structures - and the minimum requirements for strategic materials
made the project all the more attractive. It's believeable that they
knew wood structures were laregely transparent to radar - that was no
secret to anyone.
What's not believeable are after the fact claims that the 229 was
anything but what is was: a remarkable aircraft produced by talented
people under a great deal of duress.
http://www.amazon.com/Nurflugel-Geschichte-Horten-Flugzeuge-1933-1960-German/dp/3900310092
Gordon
> On Aug 4, 2:00 pm, Gordon <Gor...@oldboldpilots.org> wrote:
>
>
>
>
>
> > On Aug 1, 5:57 pm, Eunometic <eunome...@yahoo.com.au> wrote:
>
> > > The Ho 229 built by the National Geographic channel funded team at
> > > Northrop was an extremely true copy of the Ho 229 prototypes likely
> > > radar signature.
>
> > I couldn't agree less. I spent about an hour under that particular
> > replica aircraft today -- have you ever seen it in person or examined
> > its structure?
> > Euno, there is _no_ way you could call it a copy, let alone an
> > "extremely true copy". It has minimal wood bracing and the only
> > substantial
> > substructure of metal in the entire "shape" is the pilot's seat. The
> > instruments aren't real, there are no fuel tanks, radios, MLG struts,
> > wheel hubs,
> > or any of the other things that would be required to even qualify as a
> > replica. Your statement is quite incorrect.
>
> You're on the record as claiming that the Horten replica is not good a
> valid simulation of the Horten 229. Your agenda seems to be to deny
> the possibility that the Hortens and/or Germans were working towards
> airborn stealh in ww2.
there isnt anything in the WWII documentation that shows the Hortens
intentionally incorporated anything into their design for the 229 to
lower RCS. I have no agenda, I am making that statement. I have
full access to a modern full scale model, which proves nothing to the
contrary. You claimed this model is accurate to the original when
clearly it is not.
> In fact there is a lot of proof for that. There is the German Navy
> program, kicked of with a conference of 400 engineers, scientists,
> strategists etc in 1943. Then there is the Luftwaffe's FFO stealth
> program. It's clear the Germans were thinking of stealth at sea, in
> the air and on the ground.
>
> First of all let me note what the Northrop folks insisted upon this as
> being a valid way of getting a first order approximation of RCS. I
> note they are experts and experience in the area of simulating stealth
> you arew not.
agreed.
> 1 They simulated the first stage compressor with metalased plates
> fabricated to look like engine inlet compressors, the engines with
> metal tubes of demensions similar dimensions to the Jumo.
We have the benefit of having an actual Jumo, mass unsimulated, a few
feet under the flimsy 'metalized' simulated fan. It is difficult to
imagine a few ounces of paint and a lightweight disk accurately
simulates the heft and actual radar returns of a Jumo.
> 2 The internal metalic structure of the fuel tanks and metalic tube
> structure around the engines was simulated with silver paint.
>
> To a radar silver paint and an actual metalic rube or plate would look
> much the same.
Then why do they put real aircraft up on those radar test poles? Why
not just buckets of silver paint?
> The internal wood bracing is close to irrelevant.
but if that is all that is there, what else are we to discuss? Its
non-existant Formholze coating...?
> Gordon. did you even bother to watch the NG special?
Euno did you even bother to come and inspect the model? Yes, I did
watch the special.
> You might be able to look at that machine but you do not seem to
> comprehend that you would not see the silver conductive paint.
>
> Nor do you mention the conductive instrument binacle, seat, jet tubes,
> inlet compressor face, simulated tanks etc. You do mention the seat.
First you said I didn't mention the seat, then you say I did.
The mass of metal in the entire model is less than would fill the back
seat of my car.
> > > The effects of metal in the Ho 229 were simulated
> > > by the use of silver paint. (this was so conductive that the Northrop
> > > technicians demonstrated it by placing multimeter probes an inch apart
> > > on this paint and showing zero ohms resistance.)
>
> > It is not the same - its a 'similation', so its not "an extremely true
> > copy" unless the German engineers used silver paint instead of
> > engines, and rice crispies instead of oxygen tanks.
>
> A strip of silver paint looks much the same as a metal strip of tube
> of the same length and dimension.
Feel free to come to the museum and show me where all (or most, or a
majority, or even a substantial number) of the tubes were 'simulated'
by use of this paint. 99.99% of the internal structure of this model
is unpainted wood. More than anyone on the staff at the museum, I
have crawled through every open space, participated in its assembly on
the site, fitted the pilot, rigged lights to illuminate the intakes
and the cockpit, etc. Euno, its a big wood model. It's very
cool. It simply doesn't expand our understanding of German wartime
"stealth" aircraft.
> > > While the Northrop team found a significant reduction in radar
> > > reflection that would reduce detection to a tactically usfull degree
> > > this is not indicative of planed production Ho 229 radar signature.
>
> > I think they made a lovely and visually accurate full-scale model, but
> > as for proving anything about the original aircraft's stealthiness, I
> > sincerely doubt that.
>
> The flying wing, propellorless as it is, clearly has advantages.
of course. by that Captain Obvious assertion, every flying wing is a
Stealth Aircraft.
> > > The question of the Ho 229 stealth has not been settled!
>
> > certainly not by this high-quality model.
>
> > > The reason is that the Ho 229V1 and Ho 229V2 prototypes were
> > > concentionalplywoodnot the graphite impregnated formholze.
> > > Production Ho 229 would have been scaled up in size about 10% and used
> > > the formholze material.
>
> > bar napkin stuff -- there was a lack of time and it ran out, so all of
> > this is moot. The "extremely true copy"
> > did not use the formholze material, so it would only be accurate at
> > copying the initial Versuchs airframes,
> > not the dreamware Production Ho 229.
>
> > > If you wanted to reduce the radar signatue of an prop aircraft then
> > > replace the metal prop with wood or fiberglass. This is why Mosquitos
> > > were not stealthy.
>
> > But for the same reason, they had inherent stealth from their use of
> > non-strategic materials as opposed to designed
> > stealth.
>
> The fact that there are many of the shelf duel use materials hadn't
> entered into your thoughts?
Yes, I am thick that way, Euno.
How about this -- you find something from the 1939-1945 time frame
that suggests the Horten brothers were building aircraft with
incorporated radar-defeating technologies, as opposed to suggesting
that the KM was working on defending against radar, ergo, the Hortens
deliberately designed and built a stealth aircraft.
> > German airmen tasked with hunting Mosquitos reported that
> > the difficulty was not that their targets had reduced
> > RCS which limited their radar's ability to detect the British
> > aircraft, it was their morale-destroying speed.
>
> Interesting but irrelevant.
> > The fan blades on the Horten would have been far worse a radar
> > reflector than the blades of the Mosquito's Merlins --
> > I've done radar intercepts on both prop aircraft and jets and the
> > difference is incredible. The fan blades have to
> > be metal and there are dozens more than the prop blades, all
> > reflecting radar waves.
>
> This claim of yours goes against all the text books. A medium sized
> tactical jet such as a T-38 or F5 would have a smaller RCS than a
> single engined light plane.
I can tell you that from experience, pointing my radar (not a
hypothetical book's radar, but the one with the scope in front of my
face and the knobs in my gloved hands) at a twin engine jet showed a
nice firm return that I could track as it flew over the water. It
takes patience to use a surface search radar to track an airborne
contact, but with practice, it becomes a duck hunt. My point is that
our LN-66 "tuna boat radar" could paint a Lear (we use them off our
coast for Border Patrol and missile range duties) reliably. When we
encountered GA prop aircraft under the same circumstances, it was not
so easy or steady a radar return.
> Have a look at a Jumo 004. Compare the nose cone to the size of the
> prop hub on a Merlin or R-2800.
>
> Have a look at a P-2800 and its row of two cylinders and compare it to
> the inlet dimensions of a Jumo 004. Compare even the radiator scoop
> on a mustang or Lancaster and compare it to the small inlet of the
> Jumo 004.
the number of blades, all reflecting radar, is also a factor. We have
a Mustang under/alongside the Horten, and we have a Merlin right there
as well -- the /mass/ of the Jumo is far greater than what you are
comparing, and that mass, along with the stators, would make a fairly
good radar reflector. Either way, the model doesn't accurately
simulate either the production or Versuchs variant of the 229. I
didn't say, "The Germans were not aware of radar countermeasures,"
what I said was this model doesn't prove anything. The original
production plans didn't make any mention of any "Radar obsorbent
material", or "Radar dampener". Nothing in the wartime documentation
suggests or infers that the Hortens were making design choices to
limit radar interception -- these are the core facts.
> Here are the RCS published in Dorf's "The Electrical Engineering
> Handbook" for
> the following frequency ranges:
>
> Frequency range: 1-2Ghz, 3GHz, 5GHz,
>
> Small Propellor : 2.0 , 3, , 2.5
> LearJet : 1.0 , 1.5 , 1.0
> T38 : 2.0 , 2-3 , 2
> T39 : 2.5 ,? ,8
> F4 : 5-8, , 4-20, 4
> Standing Man : 0.3, ,0.5, 0.6
>
> Note a small propellor aircraft such as a piper had larger RCS than a
> Learjet or T-38/F5.
Jumos are massive metal lumps and nothing in the design, or the
mockup, suggests anything that would hide or tone down their RCS. You
can say that a Piper has a smaller RCS than a Lear, but this is off
topic -- I was commenting specifically on whether or not the model
hanging over our display floor is an accurate reproduction that
"proved" certain stealthy characteristics of the unproven "stealth"
Horten.
> Much work was done in the 1950s by Skolnik. RCS varied from 30 to
> 25db (relative to 1m^2) so about 10-50 rcs m^2 depending on viewing
> angle.http://www.radartutorial.eu/18.explanations/ex09.en.html
>
> Propellor angle modulated the strenght of the signal by as much as
> 10:1http://books.google.com.au/books?id=qZlrReU-cMkC&pg=PT28&lpg=PT28&dq=...
>
> http://www.radartutorial.eu/18.explanations/ex09.en.html
>
> I don't doubt that of viewed from a favourable angle, eg directly down
> the inlet, at a wavelenth twice that of inlet guide vanes there may be
> a strong reflection.
I agree.
> My problem with the Northrop/NG simulation is that it did not simulate
> the graphite impregnated formholze of the production versions.
yes, I said that.
> The smooth semiconducting material would have absobed internal
> reflections and also due to the smooth interuption free nature of the
> wood there would be no surface wave reflections where sheets of
> aluminium were joined. Note, the Me 163 was probably the stealthiest aircraft of WW2. No
> prop, no radiator or engine inlet and made of wood and no tail plane.- Hide quoted text -
I'd go with the Horsa, but yeah I get your point. I wonder if the
large metal fuel tanks would be visible on radar, once the waves
passed through the transparent wooden wings..
JasiekS
Uzytkownik "Eunometic" <euno...@yahoo.com.au> napisal w wiadomosci
news:86df1c44-c792-4198...@x18g2000pro.googlegroups.com...
> Quoting a fictional "usenet thread" is about as non credible as
> it
> is possible to get.
...
etc.
Wow, you took part to fictional threads! Horten's interview of '50s
was cited there, too.
Please read carefully posts by Archaeopteryx.
--
JasiekS
Warsaw, Poland
JasiekS
> This aircraft lacked the formholz of the production versions.
WHICH production versions?
--
JasiekS
Warsaw, Poland
David E. Powell
> On Aug 4, 2:00 pm, Gordon <Gor...@oldboldpilots.org> wrote:
SNIP
> The internal wood bracing is close to irrelevant.
>
> Gordon. did you even bother to watch the NG special?
I believe he actually had some hands on time with the mockup in
person...... At least I believe he mentioned that in previous posts.
> My problem with the Northrop/NG simulation is that it did not simulate
> the graphite impregnated formholze of the production versions.
>
> The smooth semiconducting material would have absobed internal
> reflections and also due to the smooth interuption free nature of the
> wood there would be no surface wave reflections where sheets of
> aluminium were joined
>
> Note, the Me 163 was probably the stealthiest aircraft of WW2. No
> prop, no radiator or engine inlet and made of wood and no tail plane.
Perhaps so, but due to range it wasn't really a plane that would leave
friendly areas and attempt penetration of enemy radar coverage.
Eunometic
<keithnos...@kwillshaw.demon.co.uk> wrote:
> "Eunometic" <eunome...@yahoo.com.au> wrote in message
No he is talking about what was seen on Wurzburg radar screens
tracking all wooden gliders used to test Horten aircraft or aircraft
made of plastic.
>
> The German radars of WW2 had no problem seeing wooden
> aircraft such as the Mosquito,
Let's compare
Stealthy Shape:
Mosquito: No
Ho 229: Yes
Absence of radar reflection antenna
Mosquito: No
Ho 229: Yes
Planed use of semiconducting graphite composit wood for production
versions
Mosquito: No (used balsa filler)
Ho 229: Yes (was to use formolz)
>
> The thing you have to recall about Reimar Horten is that he
> was giving a sales pitch but the bottom line is that he was
> basically a glider designer and never had a combat
> aircraft enter production let alone service. He was
> certainly no radar expert.
No, but he was a very intelligent person, a maverick who could produce
a jet aircraft that actually flew.
>
> The reality is any service aircraft contains enough reflective
> material to return a whacking great radar return even if
> the airframe was transparent to radar.
This is why the semiconducting material, never tested by NG would be
critical. It woild shield the internal surfaces.
> Start with two
> whacking great engines add the cannon, oxygen bottles,
> control cables, radios, batteries etc and you have something
> that any 1945 radar can pick out with ease.
Apart from engine inlet and exhaust these would all be shielded by a
semiconductor.
If the conductivity is high enough it would look like sea water.
>
> The 'success' of the stealth program of the German Navy may be
> best measured by its loss and success rates.
>
> Year Losses Sinkings
> 1939 2 167
> 1940 24 564
> 1941 35 500
> 1942 86 1321
> 1943 243 579
> 1944 249 246
> 1945 120 99 - in 5 months
Of the 120 losses in the 5 months of 1945 only 20 were to aircraft.
Over half of these in the last 2 week of the war. There were no
losses in Jan, only one in the final week of feb.
Do you think that the concentration of allmost all of the losses in
the final 2-3 weeks might have something to do with the collapse?
Most losses were to surfaces u-boats due to damage or lack of snorkel,
some were of u-boats grounded and then attacked.
Only a limited number of u-boats had the full masthead stealth
coatings applied or proper radar detectors. Some didn't even have
snorkels.
It was clear that this statistic is no reflection of German anti radar
coatings; they had not been applied yet or were of boats surface and
experiencing trouble or not equiped with proper radar warning
equipment and coatings.
Several of the fates listed in u-boat net are simply wrong, something
noted on the site.
Eunometic
> On Aug 8, 7:08 am, Eunometic <eunome...@yahoo.com.au> wrote:
>
>
>
>
>
> > On Aug 6, 5:25 am, Tinzinious Nicklefritz <1978...@gmail.com> wrote:
>
> > > On Aug 5, 2:54 pm, Juergen Nieveler <juergen.nieveler.nos...@arcor.de>
> > > wrote:
>
> > > What's more often claimed as the "stealth" ingrediant of the Ho229 is
> > > the adhesive used in bonding the skins, which includes a modest amount
> > > or charcoal dust. The interesting thing is about that is that the
> > > addition of charcoal dust to urea-based adhesives was a fairly common
> > > practice at the time and had, in fact, been patented. Not for its
> > > "stealth" qualities, mind you, but as a weight saving/structural
> > > additive, similar in concept to adding aggregate to concrete.
>
> > Duel use material. Its clear that the hortens would have been
> > improvising. They ran a small jobing shop, had no wind tunnels etc.
>
> > The Hortens lost their 3rd brother who was laying mines at night in a
> > He 111. I expect he was intercepted by radar. Loosing ones brother
> > tends to concentrate ones mind.
>
> > I have photographs of Me 109 models (Trenkle) the German used to take
> > RCS measurments. One would think that someone might come across the
> > thought that perhaps this could be minimised.
> > Duel use material. Its clear that the hortens would have been
> > improvising. They ran a small jobing shop, had no wind tunnels etc.
>
> We keep hearing that - the "duel use" claim - from people determined
> to make a silk purse from an historical sow's ear.
It took years of research, almost a decade from 1955-1965, to get a
good idea of what produces radar reflections since there are several
sources such as direct reflection, diffusion about a point, an
reflections of surface waves at sheet metal discontinuities.
On the other hand It's obvious that a sheet of wood has a vastly lower
RCS than a sheet of metal. A wooden glider has a lower RCS than a
metal aircraft of about the same size even with internal metal
structures.
If Rainer Horten, or anyone of the day was asked to reduce RCS, and
they followed their intuition in reducing RCS he would probably get a
good result from wood, flying wing and semiconducting material.
Maybe not the factor of 256 needed to get 'stealth' but certainly a
factor of 10-16 or so.
Rainer was talking about "radar camaflage" in 1950 before an
Argentinian audience.
It's clear he had the idea to produce a stealth aircraft and believed
his wooden designs were good at this. He didn't have the backing of a
major program behined him (such as the German navy) but he used wood.
>
> Strangely enough, there's no mention of this dual purpose of formholtz
> to be found in Nurflügel - Die Geschicte der Horten-Flugzeuge
> 1933-1960 ( Reimar Horten and Peter Selinger, 1983), which has a
> fairly good description of the materials.
I'm suprised if the material is mentioned at all since the Ho IX V1
and V2 did not use formholz. They had normal plywood and metal fuel
tanks. The production versions were to get the graphite impregnated
formholz and also metal free tanks made from a fuel proof glue.
>
> Reimar's comments in the quoted 1950 speech have essentially nothing
> to do with "stealth."
You might explain what the difference between "radar camaflage" and
"stealth" is then.
>
> "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. "
>
> http://www.twitt.org/Horten_May_50.html
>
> Wood structures, pure and simple. No secret to anybody, even in 1950.
>
> No mention of absorbants or other materials, no mention of any other
> procedures designed to achieve the holistic solution that later became
> known as "stealth."
Its clear that Horten was improvising with something they knew
intuitively and that we all know. Wood is less relfective to radar
than metal. Semi conducting materials absorb radar.
>
> It's already been discussed to death that regardless of the D-tube
> skinning, the 229 would have stood out like a carbon arc searchlight
> to common WWII Allied radar, especially from the forward quarters.
If it were compared with a P-38 or Me 410 it would be about 25% given
it was said to 40% of a Me 109 single engined fighter.
>
> It's believable that that the Hortens were working on a shoestring
> with a bare minumum of backing - they said as much themselves many
> times. It's believeable that they worked with what they knew best -
> wood structures - and the minimum requirements for strategic materials
> made the project all the more attractive. It's believeable that they
> knew wood structures were laregely transparent to radar - that was no
> secret to anyone.
>
> What's not believeable are after the fact claims that the 229 was
> anything but what is was: a remarkable aircraft produced by talented
> people under a great deal of duress.
We have the 1950 speech. Because they were German and out of access
to the resources of professional physicisits and radar researchers
available to western desginers they simply had no choice but to plod
along and forget their ideas of radar camaflage. If they stared to
talk about 'radar camaflage' in 1960 or 1970 they would simply be
regarded as cranks as no one believed in stealth. People didn't even
like the way the aircraft looked.
>
> http://www.amazon.com/Nurflugel-Geschichte-Horten-Flugzeuge-1933-1960...- Hide quoted text -
>
> - Show quoted text -
Tinzinious Nicklefritz
<snippage>
> Rainer was talking about "radar camaflage" in 1950 before an
> Argentinian audience.
>
Nonsense.
> It's clear he had the idea to produce a stealth aircraft (...)
Clear as proverbial mud.
It's clear you want to think he had that idea, but it's a veritable
leap across the Grand Canyon of logic to assume that just because he
was aware of the reflectivity characteristics of wood that he set out
to design a "stealth" aircraft from the get-go.
>
> > Reimar's comments in the quoted 1950 speech have essentially nothing
> > to do with "stealth."
>
> You might explain what the difference between "radar camaflage" and
> "stealth" is then.
>
Fine, as soon as you produce a direct quote of Reimar *ever* using the
term "radar camaflage" in a single sentence in his entire life.
In other words, stop putting words in his mouth. You deliberately took
two words from these two distinct sentences:
"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. "
...and attempted to make the passage say something it clearly doesn't.
Either your understanding of English is lacking, or you're
deliberately being intellectually dishonest.
<more snippage>
> > It's already been discussed to death that regardless of the D-tube
> > skinning, the 229 would have stood out like a carbon arc searchlight
> > to common WWII Allied radar, especially from the forward quarters.
>
> If it were compared with a P-38 or Me 410 it would be about 25% given
> it was said to 40% of a Me 109 single engined fighter.
Where? By whom?
Given your oft-demonstrated abilty to manufacture claims from
inference, if not thin air, I'd like to see where that figure comes
from.
> We have the 1950 speech.
Yes, we do have the 1950 speech. Thanks for trying to mangle it beyond
recognition.
> Because they were German and out of access
> to the resources of professional physicisits and radar researchers
> available to western desginers they simply had no choice but to plod
> along and forget their ideas of radar camaflage. If they stared to
> talk about 'radar camaflage' in 1960 or 1970 they would simply be
> regarded as cranks as no one believed in stealth. People didn't even
> like the way the aircraft looked.
So, now, even though the Germans "discovered stealth," it was self-
suppressed until the 1980s because of they were afraid of cultural
discrimination?
Way to play the victim card.
Keith Willshaw
"Eunometic" <euno...@yahoo.com.au> wrote in message
news:2cfdea56-be2e-4255...@i18g2000pro.googlegroups.com...
> On Aug 8, 8:51 pm, "Keith Willshaw"
> <keithnos...@kwillshaw.demon.co.uk> wrote:
>> "Eunometic" <eunome...@yahoo.com.au> wrote in message
>
>>
>> The reality is any service aircraft contains enough reflective
>> material to return a whacking great radar return even if
>> the airframe was transparent to radar.
>
> This is why the semiconducting material, never tested by NG would be
> critical. It woild shield the internal surfaces.
>
Ah you are relying on unobtanium for this purpose.
Please tell us where the Horten's could have obtained this
magical compound.
>
>> Start with two
>> whacking great engines add the cannon, oxygen bottles,
>> control cables, radios, batteries etc and you have something
>> that any 1945 radar can pick out with ease.
>
> Apart from engine inlet and exhaust these would all be shielded by a
> semiconductor.
>
Unfortunately for this plan absorbent dielectric polymers hadn't been
invented yet and would not be for some decades.
Do you plan on trying to coat them with galena diodes
which were about the only semi-conductors available ?
That might look pretty but it wont affect the RCS one jot.
> If the conductivity is high enough it would look like sea water.
>
Sea water reflects radar rather effectively. confusing reflectivity
and conductivity would be a mistake. Note metal components
are highly conductive.
>>
>> The 'success' of the stealth program of the German Navy may be
>> best measured by its loss and success rates.
>>
>> Year Losses Sinkings
>> 1939 2 167
>> 1940 24 564
>> 1941 35 500
>> 1942 86 1321
>> 1943 243 579
>> 1944 249 246
>> 1945 120 99 - in 5 months
>
> Of the 120 losses in the 5 months of 1945 only 20 were to aircraft.
> Over half of these in the last 2 week of the war. There were no
> losses in Jan, only one in the final week of feb.
>
> Do you think that the concentration of allmost all of the losses in
> the final 2-3 weeks might have something to do with the collapse?
>
> Most losses were to surfaces u-boats due to damage or lack of snorkel,
> some were of u-boats grounded and then attacked.
>
Unsurprisingly we find most ships sink due to damage.
> Only a limited number of u-boats had the full masthead stealth
> coatings applied or proper radar detectors. Some didn't even have
> snorkels.
>
Most of the losses in 1945 were of snorkel equipped boats
> It was clear that this statistic is no reflection of German anti radar
> coatings; they had not been applied yet or were of boats surface and
> experiencing trouble or not equiped with proper radar warning
> equipment and coatings.
>
> Several of the fates listed in u-boat net are simply wrong, something
> noted on the site.
>
Not so much grasping at straws as clutching at microfibres
Keith
Jim Wilkins
> Keith
This mentions the German Wesch absorbent coating, which didn't hide
Schnorchels very well, and also the American HARP paint:
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA436262
The earliest need for these materials was in the radar lab itself
where they made a small room act like an open field by absorbing
interfering reflections off the walls. The lab material looks somewhat
like black egg-crate foam with a silvery overspray. Without it you
can't even measure the pattern of an antenna without dragging it
outdoors far from an electrical outlet.
BTDT, easier than re-creating a hundred meters of frozen dirt in the
lab. We had a radio van for the test equipment but had to keep it and
its warmth away from the transmitter and receiver, on a day when the
icy Canadian gales grounded air traffic (a benefit, nothing overhead).
Luckily I kept AF mechanic's warm coveralls in my truck, the other
tech stayed huddled in the cab with the heater roaring and wrote down
the data I yelled at him over the wind. Then of course that gear was
deployed to the desert.
jsw