German Stealth Materials of WW2
Rob Arndt
other materials to make their aircraft a bit more less obvious to
radar.
In my opinion I believe the Allies were far behind this research.
One process dealt with putting a mixture of "special paint" mixed with
fine-ground coal dust and(or) some other source under-inside the
wings.
Recent documents described this work.The chief executor of this type
of research was I.G.Farben, cooperating in this field among others
with the Gdansk Polytechnic (Danzige Technische Hochschule).
Work was coordinated on behalf of this institution by the director of
chemical laboratories - a Professor Klemm.
It was written that two code-names were used to described the top-
secret project. One was "Schwarzes Flugzeug" (Black Aircraft) the
second was "Schornsteinfeger" (Chimney sweep)
...by the way, this is probably where the US Air Force got the idia to
code-name their secret stealth aircraft - Black projects !
... also known as the "skunk works"
There does not seem to be a lot of info on this subject about the
chemical properties of these "stealth paints",
but it is known the allied troops raided Prof. Klemm´s laboratories at
the end of the war where he was making his researches in the town of
Schmalkalden (Thuringia) and took all the stuff with them back to the
USA.
They also took quite a few scientists back to the USA for further
research in an operation called "Lusty" and the already known
"Paperclip" operations.
In the town of Travemunde near Lubeck, a system was found for
researching into the properties of these new materials, where numerous
samples were found of them.
These were panels made by a pressing method from powders of unknown
composition (at the time the report was made).
The substances themselves were produced in small quantities in the
laboratories of I.G.Farben in the town of Hoechst, the same company
that made "Zyklon-B", if you know what I mean?
The allies (USA) were only later able to recall and discover this
amazing "stealth" process and research by the time they got the
supersonic SR-71 "Blackbird" flying in the second half of the 1960´s!
I guess they finally figured that the supersonic jet needed some sort
of stealth paint against radar. Same thing goes for the mysterious jet
"U2" at the same time. (Ironball)
According to some papers from the WW2 era it seems that I.G.Farben
also had some help in developing this new breakthrough stealth
research. Some of those companies were...The institute of Organic
Chemistry in Danzig (prof-Klemm as already was mentioned), the Company
Osram - "Studiesngesellschaft fur Elektrische Beleuchtung" in Berlin
by a Doctor Friederich, the Laboratory of the Degussa Consortium,
which is about 8 KM from the town of Konstanz near Bodensee, made by
Prof.Fuchs and some others. Also the ceramic laboratories of the
company Lutz und Co, in the town of Lauf/Pegnitz in Bavaria, by a
Dr.Franz Rother, which is also the inventor of the "stealth" material
used on the Type XXI U-Boats.
Some other work was also done by the "Technische Hochschule in
Stuttgard (Dr.Fricke) and in Praha (Prof.Huttig)
Some interesting reports were later made by a Polish soldier who was
working in a German airfield of Sorau (Zary) near Zielona Gora, just
right after the German surrender, where it was reported seeing one
aircraft being painted with some kind of "porous" kind of paint with
some dark greyish colour left over by the Germans in a barrel...and it
was found that the Storch was made almost invisible to radar!
You will have to get Igor Witkowski´s book "The Truth about the
Wunderwaffe" to read some more info on this and other secret research
done by the Germans in WW2.
~ AHF, by MAX_theHitMan on 20 Mar 2005, 17:26
Archaeopteryx
Copied over from the Carrier thread:
Read carefully Rob - from your own post in the "Lesser Known Military
Aircraft" thread:
> The Ho-IX as well as many of the previous Horten a/c were tested
> against radar and were not picked up. If you bothered to read any of
> the books on Horten a/c they tell the same story AND the
> Schornsteifeger anti-radar paint was ready in 1945 for production a/c.
You called it "Schornsteifeger," not I.
I dug up a reference - a report by an RAF Squadron Leader - that most
emphatically debunks your statement that "Schornsteinfeger" was what
you claimed it was:
THE SCHORNSTEINFEGER PROJECT
Reported By
Sq./Ldr. G.G. MACFARLANE
(www.cdvandt.org/CIOS%20XXVI-24.pdf)
A very detailed and in-depth technical study of the stuff. Suggested
reading.
Now you want to call what you initially called "Schornsteinfeger"
something else:
> You are describing U-boat Alberich Skin which was a synthetic rubber
> Oppanol or Tarmatte which was applied to schnorkels (synthetic rubber
> + iron oxide). The Kriegsmarine may very well have used the term
> "Schornsteinfeger" also, but Ian Hogg lists it in "German Secret
> Weapons of the Second World War" (1999) pgs 213-214: " A radar
> camouflage material, consisting of a think bituminous PAINT heavily
> loaded with carbon.
No I'm not. I'm describing "Schornsteinfeger."
Know what "bituminous" means, Rob? As in "bituminous PAINT heavily
loaded with carbon." Bituminous is just another word for coal. Kind of
makes saying "bituminous PAINT heavily loaded with carbon" a bit
redundant. We'll get back to that.
Nothing against Ian Hogg, damned fine historian and RN navigator, but
I'll lend more credence to the in-depth technical analysis by an RAF
officer. Did Hogg ever mention the Formholz ("bituminous" carbon)
process skin on the H0-229? Point being that Hogg was a historian, not
a technical specialist. The above cited report is a technical
analysis.
If the Luftwaffe was using the stuff - or even a different material by
the same name, why doesn't this mystical "anti-radar paint" show up
anywhere but with Hogg?
> All your Kreigsmarine data is anti-sonar and has nothing to do with
> the Luftwaffe paint at all. The Kriegsmarine did shar anti-radar
> secrets as evidenced by the Kriegsmarine Aphrodite anti-radar U-boat
> balloon which became the Siefenblasen LW anti-radar balloon.
Say again?
> All your Kreigsmarine data is anti-sonar (...)
Whoops. No it's not. Big slip there, Rob. Need I say more?
> What a/c and where? Ho-IXV-1 unpowered version radar-tested at
> Gottingen (Sonderkommando 9). Amazingly the Ho-XIIIa also failed to
> show up on radar, but was destroyed by freed laborers- that was the
> test a/c for the projected Ho-X stealth fighter and was deliberately
> designated falsely for that purpose, pg. 59.
Flying Wings of the Horten Brothers: (Schiffer Military/Aviation
History) (Paperback)
by H.P. Dabrowski (Author), A new photo chronicle of the Horten Flying
Wing featuring new photographic material and information.)
Okay. A 64 page photo chronicle featuring "new" information. Good job
on coming up with that source. I'd feel more comfortable with it if
the event was documented a little better than in a "pictorial history
with *new* information," but hey, you found one.
By the by, any mention of the "anti-radar paint" or bituminous PAINT
in that book?
What does: Horten Ho 229 Spirit of Thuringia: The Horten All-Wing Jet
Fighter (Hardcover) by Andrei Shepelev have to say about it?
[quote]
Although the Ho 229 has been immediately identified as "stealthy" due
to 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 has evolved from the ten-year long aerodynamic
research 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."
(...)
It appears that the radar-absorbing properties of carbon had not been
known to Reimar before the late 1970s, when materials working on
similar principles were created in the USA. Perhaps this new
information led Reimar to assert his "visionary" manner that the
charcoal present inside the Formholz skin of the Ho 229 "...would
diffuse radar beams, and make the aircraft 'invisible' to radar."
Although the charcoal, being a form of carbon, could in fact dissipate
electromagnetic emissions in a limited range of wavelengths, this
substance had actually been utilized as a porous filler to lighten the
composite formed parts. Another variation of the carbon theme by
Reimar dealt with a mix of coal dust and glue that "...camouflaged 90%
of the radar cross-section of the Ho 229" and had to be applied also
to the H XVIII.
[ end quote]
No mention of paint, but...
Hmmm. One of the ingrediants of "Formholtz" is bituminous. Fancy that.
Nurflügel - Die Geschicte der Horten-Flugzeuge 1933-1960 - co-written
by Reimar himself never mentions "anti-radar paint." And somewhat more
pointedly, doesn't mention the Formholz process skin either. Nobody
ever thought is was such a big deal until "stealth" became such a
buzzword.
Nobody ever mentions "anti radar paint" or "bituminous PAINT - but you
and Hogg. Why is that?
So in review: you called the HO-229 paint "Schornsteinfeger." Then you
said it wasn't. Then you said it was an anti-sonar technology. Which
it demonstratively isn't. Nobody but you or Ian Hogg seem to have any
notion what this super secret "bituminous anti-radar paint" of yours
and his is. That about sum it up?
Good job on coming up with source on that radar test this time, Rob.
I'll give you that.
damarkley
bituminous paint can be one with a binder made from coal tar. Carbon in
paint is not typically coal derived. It is made from burning LNG or
various solvents. While coal is largely carbon it is anything but pure
carbon.
Dean
Archaeopteryx
Don't take it the wrong way, Rob, but it's paragraphs like this:
> Recent documents described this work.The chief executor of this type
> of research was I.G.Farben, cooperating in this field among others
> with the Gdansk Polytechnic (Danzige Technische Hochschule).
> Work was coordinated on behalf of this institution by the director of
> chemical laboratories - a Professor Klemm.
...that give these articles of yours the appearances of containing all
the journalistic integrity of an exclusive in the Weekly World News or
the National Enquirer.
If one may ask, precisely *what* "recent documents?
So finally, you get around to naming a source:
> You will have to get Igor Witkowski´s book "The Truth about the
> Wunderwaffe" to read some more info on this and other secret research
> done by the Germans in WW2.
A quick trip over to Amazon reveals this customer review:
[quote]
Witkowski's book is a must for anyone who liked Nick Cook's "The Hunt
for Zero Point" . In it you will find far more on the enigmatic "Nazi
Bell" device that Witkowski tantalised Cook with (the two men later
revisited the site of its supposed location for a section of Cook's
Channel 4 documentary "UFOs: the Secret Evidence").
The first section is a straightforward highly informative about the
very unusual weapons from handguns to missiles and bombers that the
Nazis were working on. The second half of the book is entirely devoted
to Witkowski's research into the Bell. I am not sure if I believe a
word of it, but it is certainly one of the most intriguing mysteries
floating around research into WW2 and weird science just now.
[end quote]
http://www.amazon.co.uk/Truth-About-Wunderwaffe-Igor-Witkowski/dp/8388259164
Why is it that any discussion of potentially plausible technologies
like this ephemeral "anti-radar paint" you're so sure existed at some
point has to come bundled with more of these laughable saucer legends?
Dan
It is, however a hydrocarbon. Just thought I'd throw that it in.
Dan, U.S. Air Force, retired
Archaeopteryx
Okiedoke, gotcha. Thanks - good catch.
Rob's elusive paint - and the other sources on the Formholtz process -
the "bituminous" component was charcoal or coal dust, depending on the
cite - hence my slip up.
The carbon component in the "Schornsteinfeger" that keeps getting
batted about came from both lamp black/carbon black, apparently:
[quote]
Semi-conducting sheets are made of ordinary paper, or
cellulose, into which lamp-black is mixed during the manu-
facturing process. To one hundred parts by weight of cell-
ulose palp, carbon-black is added in amounts ranging from 20
to 70^ by weight. Small amounts of filler are added accord-
ing to normal paper manufacture procedure. The papers are
finished in weights between 35 and 80 grams per sq meter and
with varying glosses. Control of the conductivity of the
papers was found to be very difficult and each sheet of pap-
er fabricated into a semi-conducting section of absorber
was separately measured for surface conductivity and seri-
ally numbered before shipment to the assembly plant.
Glue - Two kinds are used.
(1) For glueing layers together. It is a mixture of
5 parts of desmophen, which is a mixture of esthers (per-
haps the same as moltopren) and one part of desmoduer,
which is an isocyanate resin solution. This glue is paint-
onto the cylindrical spacers, between which the graded per-
forated absorbing sheets are sandwiched. The layers are
Page 25
pressed together without heat and allowed to s et for two
hours. Although this is the glue used in the Jaumann-Ab-
sorbers, it is not entirely satisfactory, and further work
on glue was projected.
[end quote]
Note that it's said that the glue is *painted* on. Makes one wonder if
perhaps the hullabaloo about "paint" springs from that...
<shrug>
CJ Adams
>
> Nothing against Ian Hogg, damned fine historian and RN navigator, but
> I'll lend more credence to the in-depth technical analysis by an RAF
> officer. Did Hogg ever mention the Formholz ("bituminous" carbon)
> process skin on the H0-229? Point being that Hogg was a historian, not
> a technical specialist. The above cited report is a technical
> analysis.
>
I think he was a technical specialist: Master Gunner, RA.
Cheers
CJ Adams
Archaeopteryx
Gotcha - Ian V., not Ian *T*... Thanks.
Thought it was funny that I always remembered him talking about land
artillery.
(was tracking a bunch of sources there in a short period of time)
Archaeopteryx
> other materials to make their aircraft a bit more less obvious to
> radar.
> In my opinion I believe the Allies were far behind this research.
> One process dealt with putting a mixture of "special paint" mixed with
> fine-ground coal dust and(or) some other source under-inside the
> wings.
> Recent documents described this work.The chief executor of this type
> of research was I.G.Farben, cooperating in this field among others
> with the Gdansk Polytechnic (Danzige Technische Hochschule).
> Work was coordinated on behalf of this institution by the director of
> chemical laboratories - a Professor Klemm.
> It was written that two code-names were used to described the top-
> secret project. One was "Schwarzes Flugzeug" (Black Aircraft) the
> second was "Schornsteinfeger" (Chimney sweep)
> ...by the way, this is probably where the US Air Force got the idia to
> code-name their secret stealth aircraft - Black projects !
> ... also known as the "skunk works"
[massive drivel snippage]
Let's see what the online forward to:
The Radar War, 1930-1945 by Gerhard Hepcke.
http://www.radarworld.org/books.html
http://www.radarworld.org/radarwar.pdf.
http://tinyurl.com/c4y6gd (html version)
...has to say about that, shall we?
Page 45:
S44.2 “Sumpf, Schornsteinfeger.” German Submarine Camouflage
Several procedures are tried to prevent detection by RADAR of those
parts of the submarine that are above the water surface.In most cases
measures that are supposed to disperse received signals are selective
and difficult to put into practice for a greater range of wave
lengths.
Fall 1944
Overlays of absorbing materials, e.g., rubber with deposited
semiconductor materials are more promising. If the layer is thick
enough, they are effective not only at short but also at long waves
lengths as shown by a test flight with a 1.50m ASV RADAR at the German
Aeronautic Research Institute (DVL). At this test the submarine could
be detected only by jamming with a “Metox” warning receiver.
On Feb 5, 3:10 pm, Rob Arndt <teuton...@aol.com> wrote:
>
> All your Kreigsmarine data is anti-sonar and has nothing to do with
> the Luftwaffe paint at all. The Kriegsmarine did shar anti-radar
> secrets as evidenced by the Kriegsmarine Aphrodite anti-radar U-boat
> balloon which became the Siefenblasen LW anti-radar balloon.
>
> It is entirely possible that they used the same codename for the same
> purpose- stealth.
>
> Rob
Say what?
> All your Kreigsmarine data is anti-sonar
Sorry, Rob, but NOT.
What's more, you said:
>The Kriegsmarine did shar anti-radar secrets as evidenced by the Kriegsmarine >Aphrodite anti-radar U-boat balloon which became the Siefenblasen LW anti-radar >balloon.
The Radar War, page 51:
On the other hand, German radar secrets were being leaked to the US.
For example all of the Telefunken radar patents were also patent
applied for and granted during the war in the US. As such, the German
military did everything is could to keep the radar secrets from
leaking out. People who worked on a project got to know only the one
particular aspect they were directly involved in. There was no central
point that had all the information. The Navy and the Air Force pursued
their separate developments and established their own observation
installations without exchanging data on their results.
It bears repeating:
The Navy and the Air Force pursued their separate developments and
established their own observation installations without exchanging
data on their results.
"The Radar War" lists every major Luftwaffe and Kriegsmarine project
during WWII and in a 50+ page forward, the word "paint" never occurs
even once, much less "Schwarzes Flugzeug."
Looks like your "opinions" - much less your "sources" are a little off
the mark there, Rob.
Archaeopteryx
> other materials to make their aircraft a bit more less obvious to
> radar.
> In my opinion I believe the Allies were far behind this research.
> One process dealt with putting a mixture of "special paint" mixed with
> fine-ground coal dust and(or) some other source under-inside the
> wings.
Hey Rob,
Why is it that the Luftwaffe "stealth" paint you keep babbling about
never shows up anywhere in a credible source, but research done by the
"inferior" American side is freely available with spec references?
http://pubs.drdc-rddc.gc.ca/inbasket/tfoster.041220_1303.TM%202005-003.pdf
"During World War II, Germany, concerned with radar camouflage
for submarines, developed “Wesch” material, a carbonyl iron powder
loaded rubber sheet about 0.3 inches thick and a resonant frequency
at 3 GHz. The front surface of this material was waffled to produce a
larger bandwidth. They also produced the Jaumann Absorber, a
multilayer device of alternating resistive sheets and rigid plastic.
This
device was about 3 inches thick with resistances decreasing
exponentially from the front to the back. This device achieved a
reduction in the reflectivity of –20 dB over 2-15 GHz.
America, during this period, led by Halpern at MIT Radiation
Laboratory developed materials known as “HARP” for Halpern Anti
Radiation Paint. The airborne version, known as MX-410, had a
thickness of 0.025 inches for X-band resonance. The base dielectric
had a high permittivity of 150 due to loading with highly oriented
disk
shaped aluminium flakes suspended in a rubber matrix and carbon
black for loss. This material offered a 15-20 dB reduction in
reflectivity.
Shipborne absorbers were 0.07 inch thick (X-band) iron particle
loaded
rubber with a permittivity of 20 and enough permeability to produce
resonance broadening.[11,12]
Eunometic
> On Feb 5, 3:31 pm, Rob Arndt <teuton...@aol.com> wrote:
>
>
>
> > Germany was in secrecy working on a few types of stealth "paints" and
> > other materials to make their aircraft a bit more less obvious to
> > radar.
They were not only paints but complicated materials tailed to have
progressive dielectric and conductive properties and and also
reentrant structures that trap and absorb. There was even work on a
kind of invisible stealth which worked by transmitting the wave
through the vehicle by absorbing on one side and retransmitting on the
other.
SNIP
>
> THE SCHORNSTEINFEGER PROJECT
> Reported By
> Sq./Ldr. G.G. MACFARLANE
>
> http://tinyurl.com/anrbr2
>
> (www.cdvandt.org/CIOS%20XXVI-24.pdf)
>
> A very detailed and in-depth technical study of the stuff. Suggested
> reading.
CIOS report is quite good, another source is from the German
Historian "Fritz Trenkle" he was a "bordfunker" ie a radar/radio
opperator (I think and engineer, he is very knowlegeable) after the
war he dedicated much of his life on the history of German
electronics.
One of his books "Die Deutsche Funkstoerferfahren bis 1945" basically
"German electronic countermeasures till 1945" covers what is in the
CIOS report and then some. Trenkle simply knew everyone in the
industry and was able to talk to them and grab both personal and
company archives.
Anyway on pages 139 to 143 he covers all of these with illustrations
of various structures etc. Even shows a submarine with a conning
tower shaped to disperse radar waves. Clearly the German effort was
substantial.
>
> Now you want to call what you initially called "Schornsteinfeger"
> something else:
>
> > You are describing U-boat Alberich Skin which was a synthetic rubber
> > Oppanol or Tarmatte
Alberich also had a complicated structure.
Below find a an article delivered by Reimer Horten that was published
sometime in May 1950 in Argentina.
You will note that Dr Horten refers to the importance of 'radar
camouflage' and the desirabillity of it.
He clearly was trying to emphasize 'radar camouflage' and knew that
wooden construction reduced the radar return noticeably.
I believe the small radar signature of the Horten flying wings
(probably as much to do with their shape as their materials) had been
noted from around 1943 when German radar crews helped calibrate and
gather data some of the test flights. A Wurzburg FLAK directing radar
could put its data directly into the FLAK predictor (Kommandogerat 40
or lamda predictor) which converted the polar co-ordinates into
rectangular coordinates of position, speed, climb/descent rates.
Either way the Hortens knew their designs had low radar signature and
deliberately wished to emphasize this. The use of charcole
with its semiconducting properties embedded in a sawdust glue matrix
would improve "stealth" or as Reimar called it "radar camaflage".
Reimar wasn't an electrical engineer or physicist but he knew what he
was doing worked both at an intuitive and a practical level.
The use of graphite was not in the prototypes but from the
preproduction Ho 229 (V4 onwards). I suspect Reimar and Walter would
have researched the issue and probably consulted what radar experts
they had access to.
Remember, no inkling of what the US was doing came out till the
1980's.
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
Jeff Dougherty
*powered* prototype before I accepted the Ho 229 as having a
significantly lowered radar signature. Take a quick look at this
picture of the prototype, currently stored at the National Air and
Space Museum:
http://upload.wikimedia.org/wikipedia/commons/2/21/Horton-GO229-front.jpg
Notice anything? Like the two turbojets with unshielded intakes
pointed right out the front of the fuselage? One of the things the
U.S. found out in the course of its LO program was that the rest of
the aircraft could be made out of pure radar-transparent unobtanium
shaped in curves M.C. Escher wouldn't believe, but as long as radar
could get a look at the giant, flat, spinning metal blades inside the
engine any attempt at making it stealthy was doomed. Turbine blades
make excellent radar targets, and considering that the Ho 229 seems to
have made zero effort to shield them from oncoming radar beams I would
have a hard time believing it had a significantly lower signature.
Might have been a little harder to pick up on radar a la the Mosquito,
but claims of "stealth" are just ridiculous.
I'd also encourage people claiming the design was shaped to avoid
radar to take a look at the design histories of real stealth planes
such as the F-117 and B-2. The reason the F-117 had such an angular
design was that computers at the time it was designed lacked the
capability to design a smooth shape that would deflect radar from all
directions. They had to do it as a series of polygons and facets,
which led to an airplane with that only a mother could love and only a
computer could keep reasonably flyable. By the time the design work
for the B-2 and F-22 was being done, computer technology had advanced
enough that modeling smooth radar-resistant lines was possible.
With that in mind, you'd have a very hard time convincing me that a
group of German designers in World War II managed the modeling
involved in creating a smooth radar-deflecting surface. The best
computers of the time wouldn't have been remotely up to it.
-JTD
Joe Osman
The Japanese worked on anti-radar coverings as well. See "Japanese
Anti-Radar Coverings" Report E-06 of the US Naval Technical Mission to
Japan at
http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ%20Reports/USNTMJ-200B-0278-0289%20Report%20E-06.pdf
or http://tinyurl.com/cdu8e7
There is no mention of any German-Japanese cooperation.
Joe
Archaeopteryx
Let's see here:
Eunometic wrote:
> They were not only paints but complicated materials tailed to have
> progressive dielectric and conductive properties and and also
> reentrant structures that trap and absorb. There was even work on a
> kind of invisible stealth which worked by transmitting the wave
> through the vehicle by absorbing on one side and retransmitting on the
> other.
> SNIP
The various Kriegsmarine devices consisting of multiple layers of
rubberized materials with various dielectric components have already been
referenced at length in credible, linked sources. The historical
existence of those materials is stipulated as proven and as such, do not
require further proof or discussion in this context.
Whatever research that may have been conducted on "retransmission"
technologies is beyond the scope of this discussion. This discussion is
solely limited to and contained by the statement, "...not only paints..."
> CIOS report is quite good, another source is from the German
> Historian "Fritz Trenkle" he was a "bordfunker" ie a radar/radio
> opperator (I think and engineer, he is very knowlegeable) after the
> war he dedicated much of his life on the history of German
> electronics.
> One of his books "Die Deutsche Funkstoerferfahren bis 1945" basically
> "German electronic countermeasures till 1945" covers what is in the
> CIOS report and then some. Trenkle simply knew everyone in the
> industry and was able to talk to them and grab both personal and
> company archives.
> Anyway on pages 139 to 143 he covers all of these with illustrations
> of various structures etc. Even shows a submarine with a conning
> tower shaped to disperse radar waves. Clearly the German effort was
> substantial.
Nobody has said the German effort with regard to the U Boat devices
wasn't substantial. What's been said is that there is no credible
evidence of a "stealth paint" developed by, much less employed by the
Luftwaffe.
The above quotes regarding Fritz Trenkle are very nice, but they prove
utterly nothing about the specific request for proof of Luftwaffe
"stealth paint."
> Below find a an article delivered by Reimer Horten that was published
> sometime in May 1950 in Argentina.
> You will note that Dr Horten refers to the importance of 'radar
> camouflage' and the desirabillity of it.
In the interest of brevity, let's concentrate on the segment of the
article that contains specific references to radar, and structures -
much of the this text has little to do with the topic at hand:
[quote]
> 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.
[end quote]
No question that Horten was aware of the importance of radar in
contemporary warfare. That was no secret to anyone.
However, Horten never - repeat NEVER - mentions "paint" as being
significant in any regard toward the reduction of RADAR signature
in the text. The entire quote is directed toward renewed interest in
the advantages of wooden structures as opposed to metal for its non-
reflective qualities.
This, again, is nothing new.
> He clearly was trying to emphasize 'radar camouflage' and knew that
> wooden construction reduced the radar return noticeably.
Agreed, as regards wooden structures. However, no mention is made
of "carbon," "coal," or "charcoal" anywhere in the quoted document,
much less the effect of carbon-based materials on reflectivity.
> I believe the small radar signature of the Horten flying wings
> (probably as much to do with their shape as their materials) had been
> noted from around 1943 when German radar crews helped calibrate and
> gather data some of the test flights. A Wurzburg FLAK directing radar
> could put its data directly into the FLAK predictor (Kommandogerat 40
> or lamda predictor) which converted the polar co-ordinates into
> rectangular coordinates of position, speed, climb/descent rates.
Cite, please. Your beliefs are all well and good, but they prove utterly
nothing. In fact, the listed date of 1943 precludes the possibility that
the referenced test was performed on an H0-229 as opposed to an earlier
design.
As yet, no credibly documented evidence of specific testing on the
Horten 229 design, inclusive of engines and other metallic mountings,
heat shielding, fasteners, armament and all the accouterments of even
a complete prototype aircraft in military livery have been offered. One
anecdotal report of an earlier unpowered prototype has been offered
which may support your reference. If true, that is significant, but
hardly comprehensive evidence of the true RCS signature of a production
standard warplane.
> Either way the Hortens knew their designs had low radar signature and
> deliberately wished to emphasize this.
The shape of the wing is not an issue. The wooden component of the
materials used is not an issue. That carbon-based materials contribute
some to some extent is not an issue. That the Hortens were aware of the
importance of minimizing radar signatures is not an issue. These factors
are all agreeable as having been borne out by verifiable research.
> The use of charcole
> with its semiconducting properties embedded in a sawdust glue matrix
> would improve "stealth" or as Reimar called it "radar camaflage".
Cite, please.
The listed quote in NO WAY makes any such claim. There is NO direct
usage of the term "radar camaflage" [sic] in the entire text. This is
the problem with assertions of this type - unsubstantiated claims.
(see below)
> Reimar wasn't an electrical engineer or physicist but he knew what he
> was doing worked both at an intuitive and a practical level.
Agreed. The Hortens were not physicists or electrical engineers. They
were brilliant people and aerodynamicists clearly ahead of their time.
But again, that is not the issue.
> The use of graphite was not in the prototypes but from the
> preproduction Ho 229 (V4 onwards). I suspect Reimar and Walter would
> have researched the issue and probably consulted what radar experts
> they had access to.
What additional research regarding radar signatures the Hortens had
access to, what they knew and when they knew it is precisely at the heart
of the matter, because there's precious little documentation of it.
The "Formholtz" process:
It is a well-documented fact that the Formholtz process was applied in
constructing the skins for the Ho-229 and may in actuality have had some
effect on the total RCS performance of the Ho-229. That is is not an
issue.Formholtz's potential effectiveness with regard to RCS reduction is
open to question. Documented sources also claim the coal dust/charcoal
was included as a weight saving filler in the resin layers and the
information exactly why the Hortens used the process is contradictory.
READ CAREFULLY:
The sole issue of this discussion is the appalling lack of proof
regarding persistent, yet undocumented claims that the PAINT applied to
the Ho-229 was of any special composition at all, much less a dedicated
radar absorbing agent.
End of story.
Arm waving, claims of unobtainium, pleas to authority and anecdotal
evidence consisting of hearsay do not satisfy the requirement for an
acceptably scientific standard of proof.
> Remember, no inkling of what the US was doing came out till the
> 1980's.
Which has utterly nothing to do with justifying claims made for
undocumented German research. If anything, it raises the skeptical
bar of proof for these claims because suspiciously, these stunning
claims for WWII German stealth aircraft originate at about the same
time.
Which leads to a reasonable conclusion:
That the claims of "stealth paint" having been applied to the Ho-229
are rooted in a mistake. Aspects/ingredients of the Formholtz process
were described or portrayed inaccurately at some point as being part of
the painting process - and an urban legend has formed as a result.
So the issue is really simple - various sources claim that the PAINT
on the Ho-229 was specially formulated as a radar absorbing material.
As yet, no credible, verifiable information has been offered that will
convince a reasonable person with an open mind that such is the case.
scottl...@ix.netcom.com
> As yet, no credibly documented evidence of specific testing on the
> Horten 229 design, inclusive of engines and other metallic mountings,
> heat shielding, fasteners, armament and all the accouterments of even
> a complete prototype aircraft in military livery have been offered.
This seems like it *might* be about to change. There is an upcoming
documentary:
http://www.secretprojects.co.uk/forum/index.php/topic,5851.0/highlight,229.html
"
Hitler’s Stealth Bomber (Myth Merchant Films, Calgary) It’s widely
acknowledged that Germany won the
‘aviation technology’ battle in WW2, but could the German “bat-winged”
stealth aircraft have eluded Allied
radar and changed the course of the war? Now, more than sixty years
after the Horten flying wings first took
to the air, these revolutionary aircraft will be put to the test.
Using the surviving HO 229 confiscated by the
Allies and stored by the Smithsonian Institute, the team will recreate
both the fighter jet and the massive HO
18 bomber. (Broadcaster: History Canada, National Geographic US)
"
"
More than a dozen employees showed up at El Segundo’s
Radar Cross Section model shop on a recent Saturday
morning to volunteer their services in the construction of
a full-scale wooden model of a 64-year-old German flying
wing.
Northrop Grumman is participating in a TV documentary
for the National Geographic Channel that will feature the
sector’s expertise in stealth technology and rapid proto-
typing. Northrop Grumman’s role is to build a 55-foot-
wingspan model of the Horten 229 fighter and measure its
radar signature.
"
I know nothing about this effort apart from what I've read here and a
few other places. One of the guys who worked on it seems to think that
the RCS testing gave a definitive answer, but isn't saying what that
answer is, up or down. My guess is that *if* the RCS testing was
appropriate - a wood-skinned vehicle with a *lot* of metal innards in
the form of tubes, angle irons, bits, pieces and turbojets, with some
iron oxide paint - then it'll show up just fine on radar. But if the
RCS testing was done with somethignt hat doesn't accurately reflect
the design inside and out, the RCS testign will tell us precisely
*squat.*
Archaeopteryx
<scottlowt...@ix.netcom.com> wrote:
> On Feb 8, 12:01 am, Archaeopteryx <archae...@gmail.com> wrote:
>
> > As yet, no credibly documented evidence of specific testing on the
> > Horten 229 design, inclusive of engines and other metallic mountings,
> > heat shielding, fasteners, armament and all the accouterments of even
> > a complete prototype aircraft in military livery have been offered.
>
> This seems like it *might* be about to change. There is an upcoming
> documentary:
>
Yeah, I'd seen that while bouncing around the net chasing the evidence
for this über paint I keep hearing rumors about.
That's great news and I'm all eyes and ears as to what the specific
details and findings are - the guys from the model shop at Northrop
certainly have the wherewithal to derive some decent answers to some
interesting questions at long last.
What gets terribly boring is asking a simple question - "Where's the
PAINT?" and getting the same old second-hand schmaltz tossed back -
"...well, see, der über Nazis not only had paint, they had blah, blah,
blah, blah and last but not least, they had BLAH!"
"Some interesting reports were later made by a Polish soldier..."
Great. Show me the paint.
But Herr Trenkle was a "bordfunker!"
Great! Show me some fuggin' paint already!
If they had great barrels of this stuff lying around, enough to make
*Storch ala mode* as Herr GröLaZ claims, you'd think there'd be
slightly better proof available than the bar stool recollections of a
nameless, broke-dick Polish POW.
It just gets laughable after awhile.
Dan
I hadn't really thought much about stealth WRT to Ho229. I rather
like the aircraft, but have ignored the "stealth" discussion as a whole
considering the primary flogger of such nonsense is the Aren't Frequent
Liar Club.
Even if the magic paint aren't claims existed worked as she says
there's still the intakes as you say. Further there's also the cockpit
and antennae to consider. I wonder how big a radar return all that
provides irrespective of the rest of the machine.
scottl...@ix.netcom.com
> Great! Show me some fuggin' paint already!
Indeed. After damn near seventy years, you'd think someone would have
whipped up a batch, and made their Cessna or their (as seems more
likely) AMC Pacer invisible to radar. Hell, you'd think the Russians
would have slapped a coat of charcoal onto their MiGs.
Archaeopteryx
Really.
The only scanty descriptive detail we've been afforded by the über
paint aficionados is this one:
>Ian Hogg lists it in "German Secret
> Weapons of the Second World War" (1999) pgs 213-214: " A radar
> camouflage material, consisting of a think [sic] bituminous PAINT heavily
> loaded with carbon.
Okaaaaaaaaaay........
The structure and context of the reference leads one to think that the
word "think" in the quote is a typo and the intended word was THICK.
Here's a couple of shots of the Ho-229 at Garber:*
http://g.imagehost.org/view/0881/horten (998x552)
...and a zoom in on the swastika....
http://g.imagehost.org/view/0793/horten1 (900x580)
Notice anything?
It'd be easy enough to get the obligatory 2,000 words out of the 2
photos, but in the interest of brevity, several things clearly stand
out:
1) There's nothing "thick" about the (overall green) paint at all.
Looking at the crater edges in the plywood, there's precious little
evidence of anything more than a vanishingly thin layer of color -
which makes sense if saving weight is the objective.
2) The painted white swastika is significantly thicker than the
overall green - enough so that the paint visibly cracked or "checked"
as it aged.
3) Boy, this has got to be *die wirklich gute Farbe* if it was as
effective as it's claimed to be while being used in such sparing
amounts. The scant details available regarding the use of several-
generation later Ironball paints indicate it was used somewhat
liberally for max effectiveness and was re-applied frequently.
Nothing really scientific about any of the above other than plain old
common sense.
The trouble is that the ambiguous proofs we've been offered in
rebuttal can't even crack the common sense barrier, much less the
demands of science or historical documentation.
* - photo from:
http://www.ww2aircraft.net/forum/aircraft-requests/horton-brothers-flying-wings-3618.html
tankfixer
@s20g2000yqh.googlegroups.com>, Joseph...@verizon.net says...
> On Feb 5, 3:31 pm, Rob Arndt <teuton...@aol.com> wrote:
> > Germany was in secrecy working on a few types of stealth "paints" and
> > other materials to make their aircraft a bit more less obvious to
> > radar.
> > In my opinion I believe the Allies were far behind this research.
> > One process dealt with putting a mixture of "special paint" mixed with
> > fine-ground coal dust and(or) some other source under-inside the
> > wings.
> > Recent documents described this work.The chief executor of this type
> > of research was I.G.Farben, cooperating in this field among others
> > with the Gdansk Polytechnic (Danzige Technische Hochschule).
> > Work was coordinated on behalf of this institution by the director of
> > chemical laboratories - a Professor Klemm.
> > It was written that two code-names were used to described the top-
> > secret project. One was "Schwarzes Flugzeug" (Black Aircraft) the
> > second was "Schornsteinfeger" (Chimney sweep)
> > ...by the way, this is probably where the US Air Force got the idia to
> > code-name their secret stealth aircraft - Black projects !
> > ... also known as the "skunk works"
> >
> > There does not seem to be a lot of info on this subject about the
> > chemical properties of these "stealth paints",
> > the end of the war where he was making his researches in the town of
> > Schmalkalden (Thuringia) and took all the stuff with them back to the
> > USA.
> > They also took quite a few scientists back to the USA for further
> > research in an operation called "Lusty" and the already known
> > "Paperclip" operations.
> > In the town of Travemunde near Lubeck, a system was found for
> > researching into the properties of these new materials, where numerous
> > samples were found of them.
> > These were panels made by a pressing method from powders of unknown
> > composition (at the time the report was made).
> > The substances themselves were produced in small quantities in the
> > laboratories of I.G.Farben in the town of Hoechst, the same company
> > that made "Zyklon-B", if you know what I mean?
> > The allies (USA) were only later able to recall and discover this
> > amazing "stealth" process and research by the time they got the
> > I guess they finally figured that the supersonic jet needed some sort
> > of stealth paint against radar. Same thing goes for the mysterious jet
> > "U2" at the same time. (Ironball)
> > According to some papers from the WW2 era it seems that I.G.Farben
> > also had some help in developing this new breakthrough stealth
> > research. Some of those companies were...The institute of Organic
> > Chemistry in Danzig (prof-Klemm as already was mentioned), the Company
> > Osram - "Studiesngesellschaft fur Elektrische Beleuchtung" in Berlin
> > by a Doctor Friederich, the Laboratory of the Degussa Consortium,
> > which is about 8 KM from the town of Konstanz near Bodensee, made by
> > Prof.Fuchs and some others. Also the ceramic laboratories of the
> > company Lutz und Co, in the town of Lauf/Pegnitz in Bavaria, by a
> > Dr.Franz Rother, which is also the inventor of the "stealth" material
> > used on the Type XXI U-Boats.
> > Some other work was also done by the "Technische Hochschule in
> > Stuttgard (Dr.Fricke) and in Praha (Prof.Huttig)
> >
> > Some interesting reports were later made by a Polish soldier who was
> > working in a German airfield of Sorau (Zary) near Zielona Gora, just
> > right after the German surrender, where it was reported seeing one
> > aircraft being painted with some kind of "porous" kind of paint with
> > some dark greyish colour left over by the Germans in a barrel...and it
> > was found that the Storch was made almost invisible to radar!
> >
> > Wunderwaffe" to read some more info on this and other secret research
> > done by the Germans in WW2.
> >
> > ~ AHF, by MAX_theHitMan on 20 Mar 2005, 17:26
>
> The Japanese worked on anti-radar coverings as well. See "Japanese
> Anti-Radar Coverings" Report E-06 of the US Naval Technical Mission to
> Japan at
> http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ%20Reports/USNTMJ-200B-0278-0289%20Report%20E-06.pdf
> or http://tinyurl.com/cdu8e7
> There is no mention of any German-Japanese cooperation.
>
Excelent store of reports there !
--
Meddle ye not in the Affairs of Dragons, for Thou art Crunchy and taste
Goode with Ketchup.
frank
<scottlowt...@ix.netcom.com> wrote:
> On Feb 8, 12:01 am, Archaeopteryx <archae...@gmail.com> wrote:
>
> > As yet, no credibly documented evidence of specific testing on the
> > Horten 229 design, inclusive of engines and other metallic mountings,
> > heat shielding, fasteners, armament and all the accouterments of even
> > a complete prototype aircraft in military livery have been offered.
>
> This seems like it *might* be about to change. There is an upcoming
> documentary:
>
Part of RCS is you want to see how the shape does. Build it out of
metal. You can always lower that with RAM. But if shape is crap, like
the tall tail on the early B-52s, pretty much a damn barn in the air,
not much you can do with it. Which is how F-117 and B-2 got designed.
Of course ability to build the shape is important not to mention a
minor problem of getting it to actually fly and be in controlled
flight. Pilots kinds like that.
Now we can get around all the metal inside the aircraft. Before, 70s
or so, was a real problem.
Find an F-14 GIB, ask him about counting fan blades in engine
turbines. Some of the Soviet designs had massive RADAR signatures,
pretty much, shoot me.
IT would be interesting to put together a lot of the German designs,
just to stick them into contemporary CFD systems and see how they
would fly. Granted computer time for this stuff is incredibly
expensive, maybe somebody could do a what if somewhere and write up
findings.
Eunometic
>
> > CIOS report is quite good, another source is from the German
> > Historian "Fritz Trenkle" he was a "bordfunker" ie a radar/radio
> > opperator (I think and engineer, he is very knowlegeable) after the
> > war he dedicated much of his life on the history of German
> > electronics.
> > One of his books "Die Deutsche Funkstoerferfahren bis 1945" basically
> > "German electronic countermeasures till 1945" covers what is in the
> > CIOS report and then some. Trenkle simply knew everyone in the
> > industry and was able to talk to them and grab both personal and
> > company archives.
> > Anyway on pages 139 to 143 he covers all of these with illustrations
> > of various structures etc. Even shows a submarine with a conning
> > tower shaped to disperse radar waves. Clearly the German effort was
> > substantial.
>
> Nobody has said the German effort with regard to the U Boat devices
> wasn't substantial. What's been said is that there is no credible
> evidence of a "stealth paint" developed by, much less employed by the
> Luftwaffe.
You bet it was significant: 400 experts met in 1943 to kick off the
program.
Do you think that technical folks at the Luftwaffe might have gotten
to hear about it?
>
> The above quotes regarding Fritz Trenkle are very nice, but they prove
> utterly nothing about the specific request for proof of Luftwaffe
> "stealth paint."
What is known is that there was a deep knowledge of radar absorbing
materials developing in Germany at the time.
>
> > Below find a an article delivered by Reimer Horten that was published
> > sometime in May 1950 in Argentina.
> > You will note that Dr Horten refers to the importance of 'radar
> > camouflage' and the desirability of it.
>
> In the interest of brevity, let's concentrate on the segment of the
> article that contains specific references to radar, and structures -
> much of the this text has little to do with the topic at hand:
>
> [quote]
>
> > 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.
>
> [end quote]
>
> No question that Horten was aware of the importance of radar in
> contemporary warfare. That was no secret to anyone.
More than being aware of "the importance of radar to contemporary
warfare" he also states that radar camaflauge is important and
furthermore suggests that some kind of wooden construction is suitable
for it. Bold assertions in 1950 indeed.
So he (Reimer) is on record as emphasizing radar camouflage in
1950.
Note his brother Walter, still in Germany, would go to jail if the
allied occupiers suspected that he had technical documents or
knowledge he hadn't revealed.
>
> However, Horten never - repeat NEVER - mentions "paint" as being
> significant in any regard toward the reduction of RADAR signature
> in the text. The entire quote is directed toward renewed interest in
> the advantages of wooden structures as opposed to metal for its non-
> reflective qualities.
Nope, Horten never ever mentions paint in these two documents. Nor
does anyone else ever making statements about the Go 229. You are the
only one talking about paint. Articles about the radar camouflage of
the Ho 229 go back to the use of a sawdust/carbon black/glue composite
that 'diffuses' the radar beams. There are sometimes references to
carbon black laden tar based glue which is incidently a reasonable
radar absorbing material but these don't come from Reimar or Walter,
they are either conflated or guesses or they are truly correct since
the Germans were coating the inside of the integral fuel tanks used on
the Ta 152, He 162 and Go 229 with a special fuel resistent glue.
Horten specifically mentions charcoal laden sawdust/glue/carbon black
which is often called formholze (IE "wood plastic composite" ) which
is called "formholz" which is laden with charcoal and used as the
filler in a ply. Which diffuses the beams.
>
> This, again, is nothing new.
Horten doesn't mention radar absorbing paint.
1 He thinks that 'radar camouflage' is important in 1950 when nobody
else really does.
2 He thinks a wooden based construction is a pathway to 'radar
camouflage' though he doesn't go into detail in his 1950 article.
In this Argentine article he doesn't go on about radar camouflage; he
is primarily promoting the flying wing technology he and Walther have
developed.
It is certainly believable that he intended to reduce radar signature
since he is talking about it in 1950 before anyone else was and that
means he had some experience of woods behaviour, did some research on
how to absorb radar waves or sought some advice from someone who did
know.
The DeHaviland Mosquito was flying all over Germany and it wasn't too
stealthy: that's because radar would transmit into the airframe and
bounce of undercarriages, engines, and steel parts of the structure.
I presume it had wooden prop blades as well.
I've never come across a original source that claims radar absorbent
paint, I have seen claims of radar absorbing glue. It had a sandwich
construction the inner portion of which would have been somewhat radar
absorbing.
The structure of the production Ho 229 were suppose to consist of a
high grade outer skin of wood, presumably a plywood which was followed
by a fairly thick, about 17mm inch or so, sawdust, graphite and glue
composite and it seems a final laminate lining. The whole lot
presumably being lined. The Go 60 also used 'formholz'
Here is Reimar statement:
http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/ho_ix/ho_ix_blurb/body_ho_ix_blurb.html
" The main box spar contained all cables and control rods, to free the
remaining space in the wing for fuel. That, we planned to pump right
into the wing itself, without tanks or bladders. To do this, we needed
the fuel-proof glue, that could be used to coat the inside surfaces as
well. The glue allowed additional gluing to dissolve and adhere to
already coated surfaces, which greatly simplified construction.
The skin was very thick: 17 mm, all plywood; three times the necessary
strength. On the production aircraft, this would be replaced by two
1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
glue mix, sandwiched in between. The charcoal in this much lighter
skin would diffuse radar beams, and make the aircraft "invisible" on
radar."
>
> > He clearly was trying to emphasize 'radar camouflage' and knew that
> > wooden construction reduced the radar return noticeably.
>
> Agreed, as regards wooden structures. However, no mention is made
> of "carbon," "coal," or "charcoal" anywhere in the quoted document,
> much less the effect of carbon-based materials on reflectivity.
Not the focus of his article. Reimar was trying to build aircraft in
a technologically under developed country.
The charcoal/carbon/graphite mixed in with glue & sawdust is fairly
well known. It didn't apply to the V3 that is in the USA.
Basically the aircraft are
Ho 229 v1 unpowered glider also
Ho 229 v2 jet powered, flew several hours but was destroyed in a crash
landing forced by combined effects of engine failure and asymetric
load from premature undercarriage deplyment.
Ho 229 v3 shipped to USA now at NASM
Ho 229 v4 & v4 under construction at Gotha
Ho 229 V6 under construction at Horten workshops somewhat different
from the V4 and V5
The V4,V5,V6 were all destroyed in post war 'cleanups' though they
were documented.
The later aircraft had significant changes such as cockpit layout,
pressurization, armament and other small aerodynamic changes.
The charcoal/sawdust/glue sandwich construction was not used on the Go
229 V2 and I don't believe the V3 either.
At some point the formholz (wood plastic composite) ply with the
graphite laden glue was to replace the plain ply.
>
> > I believe the small radar signature of the Horten flying wings
> > (probably as much to do with their shape as their materials) had been
> > noted from around 1943 when German radar crews helped calibrate and
> > gather data some of the test flights. A Wurzburg FLAK directing radar
> > could put its data directly into the FLAK predictor (Kommandogerat 40
> > or lamda predictor) which converted the polar co-ordinates into
> > rectangular coordinates of position, speed, climb/descent rates.
>
> Cite, please. Your beliefs are all well and good, but they prove utterly
> nothing. In fact, the listed date of 1943 precludes the possibility that
> the referenced test was performed on an H0-229 as opposed to an earlier
> design.
I can't find it, whether book but the statement I read was something
along the lines of
"It was during this time that radar crews enlisted to help calibrate
test flights reported the very low radar returns"
Similar things had been reported in regards to the Me 163:
Stüwe, Botho., p. 258 "Das Ortungsignal der Me 163 B war relativ
schwach" translates as "the radar returns on the Me 163B was
relatively weak" ... difficult Radar target, absence of dihedral
reflector (tailless). Peenemünde West (in German). Augsburg, Germany:
Bechtermünz Verlag, 1999. ISBN 3-8289-0294-4.
The Hortens were flying aircraft fully made of plastic including the
propellers, as well as all wood gliders to record heights.
>
> As yet, no credibly documented evidence of specific testing on the
> Horten 229 design, inclusive of engines and other metallic mountings,
> heat shielding, fasteners, armament and all the accouterments of even
> a complete prototype aircraft in military livery have been offered. One
> anecdotal report of an earlier unpowered prototype has been offered
> which may support your reference. If true, that is significant, but
> hardly comprehensive evidence of the true RCS signature of a production
> standard warplane.
That's because your looking for a multi million reichsmark stealth
program complete with physicists and radar experts helping the
Hortens. Such programs existed and they were very effective in
helping the u-boats cut their periscope and snorkel reflections by 95%
in the 9cm to 3cm band and they helped to analyze radar performance
against various targets. There was also a program to create false
coastlines and disguise factories and land features by in filling with
reflectors as well as creating false targets for H2S/H2X/Meddo.
What seems to have actually happened is that people noticed the weak
and difficult radar returns on wooden aircraft and gliders (which had
minimal metal parts) and thought about it a little, consulted the
text books and took an educated guess. People knew some things
absorbed (water, salt water moreso, poor conductors, some transmitted
(plastics) and some reflected they were used to seeing it on a radar
scope. There were a lot of people working with and on radar.
Carbon black does make plastics semi conductive and it does make them
absorb considerable levels of microwaves. It is used in RAM
materials, even quite modern ones though mixed in with other more
effective materials.
Idealy the "formholz" filled ply should have had a exponential
increasing carbon content to make it a juamann absorber. I doubt they
would go to the trouble.
The Hortens also built a complete plastic flying winbg aircraft,
including the propellers. It would have had a tiny radar signature.
>
> > Either way the Hortens knew their designs had low radar signature and
> > deliberately wished to emphasize this.
>
> The shape of the wing is not an issue. The wooden component of the
> materials used is not an issue. That carbon-based materials contribute
> some to some extent is not an issue. That the Hortens were aware of the
> importance of minimizing radar signatures is not an issue. These factors
> are all agreeable as having been borne out by verifiable research.
>
> > The use of charcoal
> > with its semiconducting properties embedded in a sawdust glue matrix
> > would improve "stealth" or as Reimar called it "radar camouflage".
>
> Cite, please.
http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/ho_ix/ho_ix_blurb/body_ho_ix_blurb.html
"The skin was very thick: 17 mm, all plywood; three times the
necessary strength. On the production aircraft, this would be replaced
by two 1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal
and glue mix, sandwiched in between. The charcoal in this much lighter
skin would diffuse radar beams, and make the aircraft "invisible" on
radar."
This is Reimar writing in second peson (we, meaning Walther who was
his brother and himself Reimar)
>
> The listed quote in NO WAY makes any such claim. There is NO direct
> usage of the term "radar camaflage" [sic] in the entire text. This is
> the problem with assertions of this type - unsubstantiated claims.
I would be better if you did a little more research instead of
reacting to Robert A. Remember the Hortens designed dozens of
successful flying wings. They are not 'cranks'.
This is what can be substantiated
1 Reimar asserts 'radar camouflage' is important to a jet fighter-
bomber and that wood is a pathway to it. Date 1950.
2 Reimar says that the carbon black impregnated wood plastic composite
ply would diffuse radar beams. Date about 1970
3 The planed use of the "formholz" for production aircraft can be
substantiated.
4 The F-117 is revealed to the world in 1988.
So why would Reimar make all of these statements unless he had been
informed either by practical experience, advice or calculation?
No one was promoting stealth in 1970 let alone 1950. He is supposed
to have been inspired in 1970 to assert that carbon black impregnated
was good at dispersing radar waves by the revelation of the existence
of the F-117 in 1988?
In 1950 he was working in Argentina, outcast from much of world
aviation and in limited contact with other aerodynamicists.
>
> (see below)
>
> > Reimar wasn't an electrical engineer or physicist but he knew what he
> > was doing worked both at an intuitive and a practical level.
>
> Agreed. The Hortens were not physicists or electrical engineers. They
> were brilliant people and aerodynamicists clearly ahead of their time.
> But again, that is not the issue.
>
> > The use of graphite was not in the prototypes but from the
> > preproduction Ho 229 (V4 onwards). I suspect Reimar and Walter would
> > have researched the issue and probably consulted what radar experts
> > they had access to.
>
> What additional research regarding radar signatures the Hortens had
> access to, what they knew and when they knew it is precisely at the heart
> of the matter, because there's precious little documentation of it.
The Hortens first priority was to make a high performance aircraft,
the use of wood helped many other
factors including ease of manufacture, resistence to canon fire and
'radar camouflage'
>
> The "Formholtz" process:
>
> It is a well-documented fact that the Formholtz process was applied in
> constructing the skins for the Ho-229 and may in actuality have had some
> effect on the total RCS performance of the Ho-229. That is is not an
> issue.Formholtz's potential effectiveness with regard to RCS reduction is
> open to question. Documented sources also claim the coal dust/charcoal
> was included as a weight saving filler in the resin layers and the
> information exactly why the Hortens used the process is contradictory.
>
> READ CAREFULLY:
Ofcourse it doesn't matter whether the carbon black impregnated
plastic wood known as formholz was specifically tailored to be a RAM
(Radar Absorbent Material) or whether it was chosen as material for
the Go 229 because it was identified as having Radar Absorbing
Properties. What maters is that it almost certainly will prove to
have radar absorbing properties.
I really don't believe charcoal would save weight. Its pretty heavy
compared to most wood. There are good reasons to add carbon black to
plastics: stabilizers, reinforcement or filler/extender etc but weight
saving isn't big on the list. Its SG Specific gravity: typically 1.9
- 2.1 which is more than twice as heavy than most woods and certainly
heavier than the sawdust already in use.
(formholz means mouldable-wood or plastic-wood in German, in English
the term would be plastic wood or wood plastic composit)
>
> The sole issue of this discussion is the appalling lack of proof
> regarding persistent, yet undocumented claims that the PAINT applied to
> the Ho-229 was of any special composition at all, much less a dedicated
> radar absorbing agent.
It seems to be that you are busy beating up a strawman of your own
creation, the structure of the Go 229 itself would have radar
absorbing properties, a far better idea than any 'paint' and low
returns compared to a metal structure or even a pure wood structure
yet we may still find that the glues used did contain carbon black.
>
> End of story.
End of story yourself.
End of Story.
>
> Arm waving, claims of unobtainium, pleas to authority and anecdotal
> evidence consisting of hearsay do not satisfy the requirement for an
> acceptably scientific standard of proof.
>
> > Remember, no inkling of what the US was doing came out till the
> > 1980's.
>
> Which has utterly nothing to do with justifying claims made for
> undocumented German research. If anything, it raises the skeptical
> bar of proof for these claims because suspiciously, these stunning
> claims for WWII German stealth aircraft originate at about the same
> time.
No they don't, Horten claims of radar camouflage emerge from 1950 his
claims of carbon black filled plys to diffuse radar waves come from
1970 while the F-117 is revealed in 1988 "The Air Force denied the
existence of the aircraft until 1988, when a grainy photograph was
released to the public."
>
> Which leads to a reasonable conclusion:
>
> That the claims of "stealth paint" having been applied to the Ho-229
> are rooted in a mistake. Aspects/ingredients of the Formholtz process
> were described or portrayed inaccurately at some point as being part of
> the painting process - and an urban legend has formed as a result.
A far more reasonable conclusion is that Reimar and Walter were told
of the low radar returns of their flying wings when radar crews helped
gather data on their aircraft, Reimar then realizing that radar
camouflage would be of value in a fighter bomber sought to empathize
this feature by using materials that would not reflect radar but would
also 'diffuse' the rays. Pure wood doesn't quite fit the bill
because it will allow transmission into the metal engine and
undercarriage the material turns out to be carbon impregnated wood.
He He was confident that wood worked and said as much in 1950.
Archaeopteryx
On Feb 9, 8:30 am, Eunometic <eunome...@yahoo.com.au> wrote:
[massive double talk and obfuscation snippage]
> Nope, Horten never ever mentions paint in these two documents. Nor
> does anyone else ever making statements about the Go 229. You are the
> only one talking about paint. Articles about the radar camouflage of
> the Ho 229 go back to the use of a sawdust/carbon black/glue composite
> that 'diffuses' the radar beams. There are sometimes references to
> carbon black laden tar based glue which is incidently a reasonable
> radar absorbing material but these don't come from Reimar or Walter,
> they are either conflated or guesses or they are truly correct since
> the Germans were coating the inside of the integral fuel tanks used on
> the Ta 152, He 162 and Go 229 with a special fuel resistent glue.
Ah. FINALLY we get to something relevant:
> Nope, Horten never ever mentions paint in these two documents. Nor
> does anyone else ever making statements about the Go 229.
Thank you!
>You are the only one talking about paint.
Christ on a crutch.
The very first SENTENCE in this thread made a claim about "stealth
"paints" and all I've asked for is one bit of substantive proof this
stuff ever existed:
On Feb 5, 3:31 pm, Rob Arndt <teuton...@aol.com> wrote:
> Germany was in secrecy working on a few types of stealth "paints" and
> other materials to make their aircraft a bit more less obvious to
> radar.
Then you blundered into it and said:
On Feb 7, 10:02 pm, Eunometic <eunome...@yahoo.com.au> wrote:
> They were not only paints but complicated materials tailed to have
> progressive dielectric and conductive properties and and also
> reentrant structures that trap and absorb. (...)
What part of:
> They were not only paints
...didn't YOU write?
I'm "the only one talking about paint."???
No, I'm the only one asking for PROOF this paint ever existed.
Instead, we're treated to a lecture on Formholtz, which is very nice,
but says utterly nothing about the "stealth paint" that I'm the only
one talking about.
[massive snip of arm waving about "multi million reichsmark stealth
program complete with physicists and radar experts helping the
Hortens. "]
And that's where the logic falls apart.
Why is the effort to reduce the radar signatures of U-boats is so
massively documented - with detailed technical specs? Why are the
construction methods for the Ho-229 so massively documented - with
detailed technical specs? And yet, none of these reliable sources ever
mentions that the paint on the Ho-229 - or any other Luftwaffe
aircraft - had any radar absorptive qualities whatsoever.
Instead, we're treated to rumor, hearsay and innuendo by a couple of
fans of das Reich that struggle valiantly in every thread to assert
that every interesting bit of technology absolutely, positively had to
have a Germanic origin, even if they have to resort to wild claims
they can't back up.
> > End of story.
>
> End of story yourself.
Riiiiiiiiiiiiight.
Eunometic
<scottlowt...@ix.netcom.com> wrote:
> On Feb 8, 12:01 am, Archaeopteryx <archae...@gmail.com> wrote:
>
> > As yet, no credibly documented evidence of specific testing on the
> > Horten 229 design, inclusive of engines and other metallic mountings,
> > heat shielding, fasteners, armament and all the accouterments of even
> > a complete prototype aircraft in military livery have been offered.
>
> This seems like it *might* be about to change. There is an upcoming
> documentary:
>
Probably led by this group:
http://www.phaetongroup.com/Article_pages/Phaeton_missions/PX08/Jet_wing.php
The issue here is that the production Horten Ho 229 were not not just
to be made of plywood but of a 17mm thick 'plywood' with a 14mm filler
of a wood plastic composite that was laden with carbon black, a known
radar absorber. Unless the carbon black loaded wood plastic composite
is factored in the results of any measurements they just wont be
right. Obviously an ordinary wooden surface will reflect a little
radar, absorb a little and transmit a lot (depending on thickness of
the wood). The transmitted waves will then bounce of internal parts
like engines, engine mounts, undercarriages, control cables and
scatter out again. However a semiconducting material will tend to
absorb a lot more. The transmission, absorption and reflection will
all alter, I would say quite significantly. Carbon black is a known
radar absorbing material used in radio and radar test chambers as well
as around radar antena used to reduce interference. The shape of the
Ho 229 should also tend to disperse radar waves rather than reflect
them directly back to the transmitter.
http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/horten_nurflugels.html
The main box spar contained all cables and control rods, to free the
remaining space in the wing for fuel. That, we planned to pump right
into the wing itself, without tanks or bladders. To do this, we needed
the fuel-proof glue, that could be used to coat the inside surfaces as
well. The glue allowed additional gluing to dissolve and adhere to
already coated surfaces, which greatly simplified construction.
The skin was very thick: 17 mm, all plywood; three times the necessary
strength. On the production aircraft, this would be replaced by two
1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
glue mix, sandwiched in between. The charcoal in this much lighter
skin would diffuse radar beams, and make the aircraft "invisible" on
radar.
There were also three versions of the Ho XVIII or Ho 18 bomber. The
first version was basically a scaled up Ho 229, interference by
Junkers lead to a drastic redesigne, with massive wheel and fuel
filled spats and external engines, the final version had a much higher
level of sweep, a keel fin fueselage and external mounted engines. In
those days engines had a repution for burning and no one liked having
them in the fuselage.
scottl...@ix.netcom.com
> The skin was very thick: 17 mm, all plywood; three times the necessary
> strength. On the production aircraft, this would be replaced by two
> 1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
> glue mix, sandwiched in between.
What's your reference for this? That sounds both very heavy and very
structurally dubious.
Archaeopteryx
...
> What's your reference for this? That sounds both very heavy and very
> structurally dubious.
There's a pretty decent end-on picture* of one of the Garber wing
panel here:
http://g.imagehost.org/view/0831/horten3
Whether it accurately measures out to 17mm is an open question, but
the skin (at that section) does look to be pretty thick compared to
other aircraft grade plywood skins.
Apparently, according to the link Euno provided about the Phaeton
Group investigation, there's some question as to whether these wing
panels are the correct ones for the Garber center section.
http://www.phaetongroup.com/Article_pages/Phaeton_missions/PX08/Jet_wing.php
"Cart also worked with our Mechanical Engineer Hugh Williams to
measure parts of the aircraft in our efforts to determine whether the
wings in the Smithsonian collection would indeed fit the fuselage with
which they are associated. Curator Tom Dietz reported that the three
components have apparently never been joined together to form a
complete aircraft, since the vehicle was captured by American soldiers
in an incomplete state of construction. The Phaeton report on this
mission will show whether the interfaces we measured would support a
straightforward assembly if the aircraft is ever prepared for public
display."
* - pic sourced from:
http://www.ww2aircraft.net/forum/aircraft-requests/horton-brothers-flying-wings-3618.html
Jeff Dougherty
>
> The skin was very thick: 17 mm, all plywood; three times the necessary
> strength. On the production aircraft, this would be replaced by two
> 1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
> glue mix, sandwiched in between. The charcoal in this much lighter
> skin would diffuse radar beams, and make the aircraft "invisible" on
> radar.
Again, I'd be very dubious about this as long as it has unshielded
turbojet intakes. You can make the skin radar absorbent all you want,
but giant spinning metal blades-----> no stealth for you.
-JTD
scottl...@ix.netcom.com
> On Feb 9, 12:56 pm, "scottlowt...@ix.netcom.com"
>
> <scottlowt...@ix.netcom.com> wrote:
> > On Feb 9, 7:40 am, Eunometic <eunome...@yahoo.com.au> wrote:
>
> > > The skin was very thick: 17 mm, all plywood; three times the necessary
> > > strength. On the production aircraft, this would be replaced by two
> > > 1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
> > > glue mix, sandwiched in between.
>
> > What's your reference for this? That sounds both very heavy and very
> > structurally dubious.
>
> ...
>
> > What's your reference for this? That sounds both very heavy and very
> > structurally dubious.
>
> There's a pretty decent end-on picture* of one of the Garber wing
> panel here:
>
> http://g.imagehost.org/view/0831/horten3
>
It *looks* to be about 1/4 or 3/8 inches thick, based on the
thicknesses and numbers of the separate pl;ies. But that's admittedly
handwavy.
But "two 1.5 mm plywood sheets, with a 12 mm layer of sawdust,
charcoal and glue mix" sounds like an exceedingly poor structural
material. 1.5 mm plywood is very delicate, and provides very little
tensile strength, and a mix of sawdust, glue and charcoal does not
inspire confidence from a structural standpoint.
Archaeopteryx
<scottlowt...@ix.netcom.com> wrote:
> On Feb 9, 11:16 am, Archaeopteryx <archae...@gmail.com> wrote:
>
>
>
> > On Feb 9, 12:56 pm, "scottlowt...@ix.netcom.com"
>
> > <scottlowt...@ix.netcom.com> wrote:
> > > On Feb 9, 7:40 am, Eunometic <eunome...@yahoo.com.au> wrote:
>
> > > > The skin was very thick: 17 mm, all plywood; three times the necessary
> > > > strength. On the production aircraft, this would be replaced by two
> > > > 1.5 mm plywood sheets, with a 12 mm layer of sawdust, charcoal and
> > > > glue mix, sandwiched in between.
>
> > > What's your reference for this? That sounds both very heavy and very
> > > structurally dubious.
>
> > ...
>
> > > What's your reference for this? That sounds both very heavy and very
> > > structurally dubious.
>
> > There's a pretty decent end-on picture* of one of the Garber wing
> > panel here:
>
> >http://g.imagehost.org/view/0831/horten3
>
> > Whether it accurately measures out to 17mm is an open question....
>
>
> But "two 1.5 mm plywood sheets, with a 12 mm layer of sawdust,
> charcoal and glue mix" sounds like an exceedingly poor structural
> material. 1.5 mm plywood is very delicate, and provides very little
> tensile strength, and a mix of sawdust, glue and charcoal does not
> inspire confidence from a structural standpoint.
...
Here's an enlargement of the rib/skin/gusset plate:
http://g.imagehost.org/view/0215/horten4
Looks like this set was 5 ply. Also looks to have swollen in thickness
over the years - note the indentations around where fasteners
(screws?) compress the skin to the rib. IIRC, the Garber wing sat
outside for a few years.
> But "two 1.5 mm plywood sheets, with a 12 mm layer of sawdust,
> charcoal and glue mix" sounds like an exceedingly poor structural
> material. 1.5 mm plywood is very delicate, and provides very little
> tensile strength, and a mix of sawdust, glue and charcoal does not
> inspire confidence from a structural standpoint.
Not a plywood expert, but that doesn't sound too spiffy for torsional
loads either - something it'd be seeing a lot of. Not to mention that
the Germans had significant difficulty with adhesives as well (He-162,
Ta-154...) .
There's bound to be a materials guy or two (with credible experience)
around here that could offer some very insights about that.
guy
>
> - Show quoted text -
I am no expert, but I would suggest looking at the Mosquito plywood/
balsa fuselage - let me know if you find anything.
Guy
Dan
Termites?
Eunometic
> I'd really want to see some kind of cite about tests done with the
> *powered* prototype before I accepted the Ho 229 as having a
> significantly lowered radar signature. Take a quick look at this
> picture of the prototype, currently stored at the National Air and
> Space Museum:
>
>
> Notice anything? Like the two turbojets with unshielded intakes
> pointed right out the front of the fuselage?
Yes the inlets are exposed but they certainly don't point out in front
of the fueselage, they are recesed behined the leading edge.
Check a plan view.
One of the things the
> U.S. found out in the course of its LO program was that the rest of
> the aircraft could be made out of pure radar-transparent unobtanium
> shaped in curves M.C. Escher wouldn't believe, but as long as radar
> could get a look at the giant, flat, spinning metal blades inside the
> engine any attempt at making it stealthy was doomed.
I know that first stage compressor blades show up on radar after
having bounded down the inlets, you can infact analyse the engine type
and number from the Fourier signature.
However we aren't dealing with modern radars that have signal
processors attached and in some cases cooled receivers so that they
can handle ultra low signal to noise ratios. The Ho 229 would be
dealing with WW2 radars.
Compare a Ho 229 with say a Ju 188, Douglass A-26 Invader or a P-47.
All these aircraft have massive radial piston engines with an array of
14 or 18 cylinders behined very short ducts. They also have huge 3 or
4 bladed metal props that form massive reflectors, German Wurzburg
radar equiped with "nurenburg" system detected the props motion in
order to see through windows jamming. The jumo 004 Inlet area of the
Ho 229 is somewhat less and recessed far enough behined the leading
edge that they would be hidden outside about the 10.30 and 1.30
o'clock position. There are no props.
The Ho 229 is completely wood, with enough charcoal to stop internal
reflections. The Me 163 was know to have a low radar signature due
to its partial wood construction and lack of tail (which traps and
scatters radar waves) the Northrop YB-49, despite being all metal had
an exceptionally low radar signature.
So let analyse the airframe and engine reflections seperatly: assume
the Ho 229 material has 1/4th to 1/8th the reflection of metal and
assume the airframe has 1/4th to 1/8th the reflection due to its
flying wing shape. Apart from the tangential part of the leading edge
there is not much to reflect to the surface.
So I'd hazzard a guess that the airframe of the Ho 229 would have
1/16th to 1/64th the signature of a conventional single engine all
metal fighter. You need to reduce radar returns by 16:1 to halve
detection range.
Now the engines are going to reflect fair bit but they are smaller
than a knobbly radail engine with its big gilled cowling and they lack
propellor blades. I'd say just on frontal area alone that the jet
engines would have 1/4th to 1/8th the reflection of a piston engine
with prop. Water cooled engines, with their big scoops and propellor
bosses are probably not better.
assume that engines were half the reflection than the Ho 229 has 1/4th
to 1/16th the radar cross section.
With an penetration speed of about 580mph (say 250 meters/second) at
11,000m (26000ft) it would stand a good chance of reducing detection
range in half from say 60-80km (40-50 miles) to say 30-40km. That
means that warning time is reduced from about 5 minutes to 2.5
minutes. WW2 fighter aircraft climbed at 4000ft a minute, a P-47
2800ft/minute. There is no chance to get to height let alone
intercept it.
Even if it only saves 1 minute I think its tactically significant.
As the German experience grew and they analyzed the aircraft they
might coat the inlet tube, engines support spider and intake cone with
paints or absorbers, generally able to absorb 90% or so with ease
though the compressor blades would still be exposed it could be hidden
by inlet stators as in that 1940 Lockheed designed turbojet, the J-37
(L-1000)
I agree it isn't the 1000;1 reduction required for true stealth but I
think it would present a difficult to detect target, especially if
viewed from the side quadrants and reduce warning time.
Archaeopteryx
As much as anything, it's more helpful to look into the various
processes for plywood manufacturing - especially in the areas of
adhesives and curing agents.
The problem here is that information about this famous "Formholtz"
plywood is sparse to non-existent outside of the nebulous references
to it as a Wundermaterial in the Horten wings. By comparison, there's
bags of information about the Goldschmidt Tego film process*, lack of
availability of which famously caused the demise of the Ta- 154.
Point being that it's a little premature to claim that the carbon/
charcoal ingredient of the Horten skin was a dedicated stealth
device.
It's hard to say with any certainty what the purpose behind adding
charcoal to the resin actually was, because we don't know the formula
for the base resin of "Formholtz" itself. There were two distinct
classes of resins used in plywoods of the era: casein (a dairy
byproduct) and urea or phenol formaldehydes.
As it turns out, the addition of charcoal to formaldehyde-based resins
confers some benefit to the curing process and increases shear
strength:
[quote]
Résumé / Abstract
In this study we investigated the effects of using four additives,
wheat flour (WF), tannin, ' rice husk (RH) and charcoal, to melamine-
formaldehyde (MF) resin for decorative veneer and base plywood in
engineered flooring in order to reduce the formaldehyde emission
levels and improve the adhesion properties. We determined the effects
of variations in hot-press time, temperature and pressure on the
bonding strength and formaldehyde emission. Blends of various MF resin/
additive compositions were prepared. To determine and compare the
effects of the additives, seven MF resin blends were prepared with the
four different additives: four with a wt ratio of 8:2 (MF/WF, MF/
tannin, MF/RH and MF/charcoal), and three in the wt ratio of 8:1:1 (MF/
WF/tannin, MF/WF/RH and MF/WF/charcoal). The desiccator and perforator
methods were used to determine the level of formaldehyde emission. The
formaldehyde emission level decreased with all additives, except for
RH. At a charcoal addition of only 20%, the formaldehyde emission
level was reduced to nearly 0.1 mg/l. Curing of the high WF and tannin
content in this adhesive system was well processed, as indicated by
the increased lap-shear strength.
http://cat.inist.fr/?aModele=afficheN&cpsidt=18794411
[end quote]
It's precisely the lack of specific information about the
manufacturing process that allows for jumping to rather hasty
conclusions to support an assertion that just because the skin
included a form of carbon that it is evidence of dedicated stealth. As
it turns out, it is just as likely - and more verifiable - that the
inclusion of carbon into the resin mix was as much - if not more -
about structural issues than any RCS benefit it may have conferred.
The point is, we just don't know.
* - http://www.degussa-history.com/geschichte/en/inventions/glue_film/
Ken S. Tucker
> It's precisely the lack of specific information about the
> manufacturing process that allows for jumping to rather hasty
> conclusions to support an assertion that just because the skin
> included a form of carbon that it is evidence of dedicated stealth. As
> it turns out, it is just as likely - and more verifiable - that the
> inclusion of carbon into the resin mix was as much - if not more -
> about structural issues than any RCS benefit it may have conferred.
>
> The point is, we just don't know.
I know, see,
http://en.wikipedia.org/wiki/Sandwich_structured_composite
same principle as the corrogated cardboard box.
In stock we have something called "foamboard" made by
Elymers, consisting of two pieces of shiny cardboard with
regular styrofoam sandwiched, it's very rigid for it's weight,
(available at Staples).
Carbon is not required, so it's expensive inclusion was for
a purpose apart from structural needs, supporting the
probability of Radar Stealth.
Ken
Archaeopteryx
While poking about for more information on the Go-229, I found this
little gem:
AAF TRANSLATION
NO.
525
F -TS525- RE
English Title:
COMPARISONS OF THE 8-229 AND THE
GO P-GO ALL-WING AIRPLANES
German Title:
GEGENÜBERSTELLUNG 8-229 GO P-60
Author: Nauber
Date Prepared:
Release Date:
21 February 1946 22
April 1946
Full text available at: http://149.142.139.138/Web/229vsP60.html
Contains utterly no reference to RCS issues whatsoever, but it's a
pretty nifty historical document in its own right as well as a good
single-source reference for detailed flight characteristic data on the
Go-229.
Archaeopteryx
Well, at least the 15mm total thickness is an improvement on a
previous claim:
On Apr 22 2005, 12:12 am, "Eunometic" <eunome...@yahoo.com.au> wrote:
>
>
> Part of the radar absorbant material on the Go/Ho 229 was supposed to
> be a glue/sawdust/graphite RAM filler between the double plywood skins
> about one inch thick. It wasn't just a 'paint' or coating although
> this existed as well.
>
[grin]
Archaeopteryx
> On Feb 8, 8:30 pm, "scottlowt...@ix.netcom.com"
> <scottlowt...@ix.netcom.com> wrote:
> > On Feb 8, 12:01 am, Archaeopteryx <archae...@gmail.com> wrote:
> > > As yet, no credibly documented evidence of specific testing on the
> > > Horten 229 design, inclusive of engines and other metallic
> > > mountings, heat shielding, fasteners, armament and all the
> > > accouterments of even a complete prototype aircraft in military
> > > livery have been offered.
> > This seems like it *might* be about to change. There is an upcoming
> > documentary:
> >
http://www.secretprojects.co.uk/forum/index.php/topic,5851.0/highligh...
> Probably led by this group:http://www.phaetongroup.com/Article_pages
>/Phaeton_missions/PX08/Jet_w...
...
> Probably led by this group:http://www.phaetongroup.com/Article_pages
>/Phaeton_missions/PX08/Jet_w...
Just received an email from Phaeton in regards to the paint on the
Garber wing:
**********************
Thank you for your interest in this Phaeton Group project.
Clarifying the accuracy of claims regarding the purported low-
observable qualities of the Ho-229 is one of my particular goals with
this project.
Consideration of coatings, including paint, will certainly form part
of Phaeton's investigation report.
A complicating factor in connection with this line of inquiry is the
fact that the aircraft we examined does not appear to have been a
finished,flight-ready vehicle at the time of its capture. Furthermore,
comparisons with the earliest avaiable photographs seem to show that the
present paint job is not original to the aircraft.
It is my impression at this point in the project that the Ho-229
probably did incorporate some deliberate low-observable measures in its
construction, but I am not at present aware of any convincing evidence
for paint being one of those measures.
Other projects have preoccupied our small organization since my team
and I examined the Horten, and our publication of a report has been
delayed. However, we remain very interested in completing the project and
sharing our findings on this most remarkable aircraft. I hope that in our
final article we will be able to furnish a satisfactory consideration of
the question of "stealth paint."
I appreciate your inquiry and your kind words. I hope that you will
let us know what you think when Phaeton is able to publish more about the
Ho-229.
Regards,
Dr. David West Reynolds
Paul A. Suhler
upcoming National Geographic Channel show, "Masters of Stealth."
As part of this, they built a model of one of the Horten aircraft
and measured its RCS. Look for it later this year.
Paul
Archaeopteryx
Thanks - somebody mentioned that up-thread a bit.
It'll be interesting to see how detailed the model is vs. what's known
about the original articles - which will have a large effect on how
accurate the results are. That said, if the guys from the Northrop
model shop are behind it, they doubtless know what is required to do
the job right.
Definitely worth a watch...
JasiekS
Uzytkownik <scottl...@ix.netcom.com> napisal w wiadomosci
news:765f73b6-f6ff-448a...@w24g2000prd.googlegroups.com...
> It *looks* to be about 1/4 or 3/8 inches thick, based on the
> thicknesses and numbers of the separate pl;ies. But that's admittedly
> handwavy.
I counted 7 plies and assume this could make 10 mm thickness (slightly
more than 3/8").
> But "two 1.5 mm plywood sheets, with a 12 mm layer of sawdust,
> charcoal and glue mix" sounds like an exceedingly poor structural
> material. 1.5 mm plywood is very delicate, and provides very little
> tensile strength, and a mix of sawdust, glue and charcoal does not
> inspire confidence from a structural standpoint.
Why? This is the way sandwich structures work. External layers (plywood)
take stress and filling (sawdust etc.) keeps them in fixed distance from
each other. I don't understand the role of third plywood layer; if it's
positioned in the middle it takes little stress. Of course no traces of
sandwich structure are in the pictures of Ho-229 V3.
BTW center section is extensively covered with metal sheets.
--
JasiekS
Warsaw, Poland
JasiekS
Użytkownik "JasiekS" <jasieks...@please.poczta.onet.pl> napisał w
wiadomości news:gmueo3$k16$1...@news.onet.pl...
> I don't understand the role of third plywood layer; if it's
> positioned in the middle it takes little stress.
Ooops! Idon't know where I get third plywood layer from. Sorry!
--
JasiekS
Warsaw, Poland
Ken S. Tucker
wrote:
> U¿ytkownik "JasiekS" <jasieks.no.s...@please.poczta.onet.pl> napisa³ w
> wiadomo¶cinews:gmueo3$k16$1...@news.onet.pl...
>
> > I don't understand the role of third plywood layer; if it's
> > positioned in the middle it takes little stress.
>
> Ooops! Idon't know where I get third plywood layer from. Sorry!
15mm ~ 5/8" plywood (sandwich) sounds ok for a structure
of that size, the data is loose, but the theory is sound.
> JasiekS
> Warsaw, Poland
Ken
Archaeopteryx
>
> > I don't understand the role of third plywood layer; if it's
> > positioned in the middle it takes little stress.
>
> Ooops! Idon't know where I get third plywood layer from. Sorry!
>
> --
> JasiekS
> Warsaw, Poland
Jasiek - that's what the better part of this thread is about; sorting
through what's out there to come to a better understanding of what
actually was. There's a lot of rumor, speculation and pronouncements
via unsubstantiated claims, but precious little documented fact - the
best example yet are the extraordinary claims about "stealth paint"
nobody seems to be able to back up.
Found this quote by Joe Baugher, a very well respected researcher that
adds another bit of mystery to the mix about the use of the plywood
sandwich material:
[quote]
The Ho IX V2 was designed for a 7g safe load factor. The center
section of the wing housed the engines and the cockpit and was made of
conventional welded steel-tube construction. The center section was
covered with plywood skinning except in the immediate vicinity of the
engine exhausts, where metal was used. The outer wings were made
entirely of wood. The outer wing leading edges were constructed of a
special molded wood (wood shavings compressed with resin), but the
rest of the wing was covered with plywood. A special coating of
lacquer was applied to give a smooth finish to the entire aircraft. I
think that the idea of the lacquer finish was to give an
aerodynamically smooth surface rather than to provide any "stealth"
characteristics--that was still many, many years in the future.
Source: Warplanes of the Third Reich, William Green. Doubleday, New
York, 1970.
[end quote]
"...The outer wings were made entirely of wood. The outer wing
leading edges were constructed of a special molded wood (wood shavings
compressed with resin), but the
rest of the wing was covered with plywood."
So if that quote is accurate, the sandwich material may have not been
applied entirely to the skin, but as a structure to form the D-tube
for the leading edge of the outer wing panels.
One picture that seems to emerge is that there are distinctions to be
made between the 299 at NASM Garber - a prototype - and details in
the works for eventual production machines.
guy
wrote:
> Uzytkownik <scottlowt...@ix.netcom.com> napisal w wiadomoscinews:765f73b6-f6ff-448a...@w24g2000prd.googlegroups.com...
Similar to the Mosquito, balsa wood sandwiched between 2 layers of
plywood. Sorry, I do not have the thicknesses though.
Guy
Archaeopteryx
Here ya go:
"De Havilland engineers and technicians used generally the same
techniques to construct the Comet, Albatross, and Mosquito mainplanes
out of wood and plywood. When they designed and built the fuselage,
however, they copied the methods and materials employed to build the
Albatross fuselage. This airliner was the product of the brilliant
mind of Arthur E. Hagg, de Havilland's Chief Draftsman in 1937. He
left the company that same year but his ideas lived on in the
Mosquito. Hagg created a light, strong, very streamlined structure by
sandwiching 9.5mm Ecuadorian balsa wood between Canadian birch plywood
skins that varied in thickness from 4.5mm to 6mm."
source:
http://www.airforce.gov.au/raafmuseum/exhibitions/restoration/dh_98.htm
scottl...@ix.netcom.com
wrote:
> Uzytkownik <scottlowt...@ix.netcom.com> napisal w wiadomoscinews:765f73b6-f6ff-448a...@w24g2000prd.googlegroups.com...
>
> > It *looks* to be about 1/4 or 3/8 inches thick, based on the
> > thicknesses and numbers of the separate pl;ies. But that's admittedly
> > handwavy.
>
> I counted 7 plies and assume this could make 10 mm thickness (slightly
> more than 3/8").
>
> > But "two 1.5 mm plywood sheets, with a 12 mm layer of sawdust,
> > charcoal and glue mix" sounds like an exceedingly poor structural
> > material. 1.5 mm plywood is very delicate, and provides very little
> > tensile strength, and a mix of sawdust, glue and charcoal does not
> > inspire confidence from a structural standpoint.
>
> Why? This is the way sandwich structures work. External layers (plywood)
> take stress and filling (sawdust etc.) keeps them in fixed distance from
> each other.
Two problems I have:
1) 1.5 mm plywood cannot take very much stress. I work with plywood
that thickness on occasion; it tears easily.
2) The structural core material should have a combination of low
density and high compressive strength. That's why balsa wood and
alluminum honeycomb work well here. But sawdust, glue and charcoal
does not necessarily seem to meet those requirements. Of course,a lot
of it would be down to exactly what ratios... and what glue.
JasiekS
Uzytkownik "Ken S. Tucker" <dyna...@vianet.on.ca> napisal w
wiadomosci
news:439bc9ad-23ca-497a...@z2g2000prg.googlegroups.com...
> 15mm ~ 5/8" plywood (sandwich) sounds ok for a structure
> of that size, the data is loose, but the theory is sound.
I doubt it. As I wrote earlier there are 7 plies visible in the
picture so single ply would be ~2 mm. Normally a plywood of 15 mm
thickness would be 9 or 11 plies thick.
--
JasiekS
Warsaw, Poland
guy
>
> - Show quoted text -
Thanks:-)
Lovely airliner the Albatross too,
here is an RAF one
http://farm2.static.flickr.com/1154/767810061_43ab925e88.jpg?v=0
Guy
JasiekS
Uzytkownik "Archaeopteryx" <arch...@gmail.com> napisal w
wiadomosci
news:a98defb9-5675-4bb5...@33g2000yqm.googlegroups.com...
> [quote]
> The Ho IX V2 was designed for a 7g safe load factor. The center
> section of the wing housed the engines and the cockpit and was
> made of
> conventional welded steel-tube construction. The center section
> was
> covered with plywood skinning except in the immediate vicinity of
> the
> engine exhausts, where metal was used. The outer wings were made
> entirely of wood. The outer wing leading edges were constructed
> of a
> special molded wood (wood shavings compressed with resin), but the
> rest of the wing was covered with plywood. A special coating of
> lacquer was applied to give a smooth finish to the entire
> aircraft. I
> think that the idea of the lacquer finish was to give an
> aerodynamically smooth surface rather than to provide any
> "stealth"
> characteristics--that was still many, many years in the future.
> Source: Warplanes of the Third Reich, William Green. Doubleday,
> New
> York, 1970.
> [end quote]
You provided us earlier with the link to discussion in some other
group. Most of them are (probably) young enthusiast but two or three
cited detailled description of the construction and provided further
links to more photos and drawings. It is worth to go through the
whole 11-pages discussion.
According to these description the wing was designed in monocoque
sructure. Monocoque means that the skin is stiff enough and don't
need ribs or longerons - with exception of places, where external
forces have to be applied perpendicular to the skin (e.g. landing
gear, control surfaces' vanes, etc.).
One digression here. Aero structures usually fall into thin-skin
(terminology?) cathegory. They could be heavy stressed as long as
loads come coplanar with the skin. After reaching some critical
stress (depending on geometry, boundary conditions and Young
mondulus) the skin loses stability and 'buckles'. This buckling can
lead to cracks and damage of construction. Sometimes skin is
dimensioned not according to stress but according to resistance to
stability loss. Sandwich constructions were invented to avoid this
problem. External layers take all stress and filler (would it be
balsa, paper honeycomb, sawdust+glue, foams, etc.) prevent from
buckling (loss of stability) as long as they are fixed (glued) with
external layers.
Back to Ho-229 wing. Monocoque fore part (sandwich or thick plywood)
closed with the spar build rigid beam resistant to both bending and
torsional loads. Rear part (behind the main spar) is ambivalent for
the wing structure. It could be covered with thinner skin because
loads from that part are introduced via ribs. Pressure coefficients
in this region are normally smaller than around leading edge. Of
course wings intended for high speed should be smooth hence lacquer
coating.
> So if that quote is accurate, the sandwich material may have not
> been
> applied entirely to the skin, but as a structure to form the
> D-tube
> for the leading edge of the outer wing panels.
I am sure it is.
--
JasiekS
Warsaw, Poland
JasiekS
> Two problems I have:
> 1) 1.5 mm plywood cannot take very much stress. I work with
> plywood
> that thickness on occasion; it tears easily.
1.5 mm comes from Euno's post. I didn't check this value. A 1.5 mm
plywood is piece of cake IF IT WORKS ALONE. Applying of double layer
with filler (core material as you said) changes support (or
boundary) conditions so that the skin don't lose stability.
One example: you have typical H-beam (e.g. wing's main spar) with
massive upper anl lover shelves and very thin middle part. You
applied bending to this beam. In any section of this beam bending
causes normal (axial) loading of the shelves and shear in the middle
part. If the shear is high enough beam's middle part loses stability
(normally it cracks diagonally) and the beam breaks. What shouuld
you do, assuming trat shelves' cross sections are big enough? You
have two ways: made middle part thicker (but the weight increases)
or... change boundary conditions. It is sufficient to add some ribs
(they don't need to be massive) to the middle part so they divide
it's area into smaller sections. It will crack at greater loading.
Support conditions are very important for stability of thin-skin
structure.
> 2) The structural core material should have a combination of low
> density and high compressive strength. That's why balsa wood and
> alluminum honeycomb work well here. But sawdust, glue and charcoal
> does not necessarily seem to meet those requirements. Of course,a
> lot
> of it would be down to exactly what ratios... and what glue.
Not exactly. Core material should be of low density but it's
compressive strenghth is irrelevant. Did you see a section of
honeycomb sandwich? Total strength of the honeycomb is oriented
perpendicular to the skin; a honeycomb's strength component coplanar
with skin is practically zero! You can take whole block of honeyconb
(before glueing with the skin) and squeeze it flat with two fingers.
Honeycomb is produced from strips of paper (or alluminium film)
glued locally (every second layer in the same place; neighbour
layers in the middle[*]) and then stretched to form honey cells. The
only assignement of core is to fix external layers (i.e. to change
their support conditions).
[*] I am not shure if my explanation is understandable. Here is a
kind of sketch.
| - means lose strip
o - means glueing point.
|o| |o| |o| |
| |o| |o| |o|
|o| |o| |o| |
| |o| |o| |o|
|o| |o| |o| |
| |o| |o| |o|
etc. They are stretched in this direction <-- |o| |o| |o| | -->
--
JasiekS
Warsaw, Poland
Archaeopteryx
wrote:
> Uzytkownik "Archaeopteryx" <archae...@gmail.com> napisal w
> wiadomoscinews:a98defb9-5675-4bb5...@33g2000yqm.googlegroups.com...
...
> You provided us earlier with the link to discussion in some other
> group. Most of them are (probably) young enthusiast but two or three
> cited detailled description of the construction and provided further
> links to more photos and drawings. It is worth to go through the
> whole 11-pages discussion.
The description from:
http://www.ww2aircraft.net/forum/aircraft-requests/horton-brothers-flying-wings-3618-3.html
...was copied to that forum from:
http://www.twitt.org/Farnborough_05.html#top
FARNBOROUGH HANTS
The Horten Tailless Aircraft
by K.G. Wilkinson, B.Sc. D.I.C.
Horten VIII & IX
... most of the forum thread is indeed "young enthusiast" type banter
rather than anything of strict technical or historical value aside
from the photos and eventually spins off into the obligatory
conspiracy speculations.
[quote]
Structure
Wing structure comprised a main spar and one auxiliary spar or
wooden construction with ply covering. The center section was built
up from welded steel tube. Wing tips were all metal*. The
undercarriage was completely retractable and of tricycle type the
front wheel folding backwards and the main wheels inwards. The nose
wheel was castering and centered with a roller cam. When resting on
the ground, wing incidence was 7° and the nose wheel took about 40% of
the total weight.
[end quote]
One question: If the properties of the skin sandwich were deliberately
engineered with stealth in mind, why design an aircraft around them
and then give it metal wingtips?
Just one more detail that weighs against the "dedicated stealth"
claims.
> > So if that quote is accurate, the sandwich material may have not
> > been applied entirely to the skin, but as a structure to form the
> > D-tube for the leading edge of the outer wing panels.
>
> I am sure it is.
Which is really the point; over the years, some wild claims have been
made about the dimensions (up to 1" - 25.4mm thick!), properties and
use of this sandwiched skin as conclusive evidence of an early attempt
at "stealth." The problem with leaping to that conclusion - aside from
the lack of (pre-1970s) documentation of the effort - is that there
were sound design considerations and manufacturing/procurement issues
why those materials were selected and used given the dire wartime
situation the Hortens were faced with.
The vast majority of the writings by Horten deal with their desire to
eliminate parasitic drag and produce an optimal "bell shaped" lift
curve. The 229 was a stunningly advanced attempt to achieve that end.
While it's reasonable to believe that the Hortens were pleased when
they became aware of the low RCS value of their designs vs.
contemporary aircraft in the testing process (as Northrop was), that
feature was more likely to be a result of "good engineering luck" than
a specific goal.
Despite the spectacular claims of that a dedicated knowledge of
"stealth" was incorporated into the 229 several generations ahead of
its time, a bit of rational examination goes a long way towards
forming an opinion that those claims are driven more by agenda than
credible research.
Joe Osman
> In article <241d489c-974b-4f54-b27e-a5e31c7df545
> @s20g2000yqh.googlegroups.com>, Joseph.Os...@verizon.net says...
>
>
>
>
>
> > On Feb 5, 3:31 pm, Rob Arndt <teuton...@aol.com> wrote:
> > > Germany was in secrecy working on a few types of stealth "paints" and
> > > other materials to make their aircraft a bit more less obvious to
> > > radar.
> > > In my opinion I believe the Allies were far behind this research.
> > > One process dealt with putting a mixture of "special paint" mixed with
> > > fine-ground coal dust and(or) some other source under-inside the
> > > wings.
> > > Recent documents described this work.The chief executor of this type
> > > of research was I.G.Farben, cooperating in this field among others
> > > with the Gdansk Polytechnic (Danzige Technische Hochschule).
> > > Work was coordinated on behalf of this institution by the director of
> > > chemical laboratories - a Professor Klemm.
> > > It was written that two code-names were used to described the top-
> > > secret project. One was "Schwarzes Flugzeug" (Black Aircraft) the
> > > second was "Schornsteinfeger" (Chimney sweep)
> > > ...by the way, this is probably where the US Air Force got the idia to
> > > code-name their secret stealth aircraft - Black projects !
> > > ... also known as the "skunk works"
>
> > > There does not seem to be a lot of info on this subject about the
> > > chemical properties of these "stealth paints",
> > > but it is known the allied troops raided Prof. Klemm?s laboratories at
> > > the end of the war where he was making his researches in the town of
> > > Schmalkalden (Thuringia) and took all the stuff with them back to the
> > > USA.
> > > They also took quite a few scientists back to the USA for further
> > > research in an operation called "Lusty" and the already known
> > > "Paperclip" operations.
> > > In the town of Travemunde near Lubeck, a system was found for
> > > researching into the properties of these new materials, where numerous
> > > samples were found of them.
> > > These were panels made by a pressing method from powders of unknown
> > > composition (at the time the report was made).
> > > The substances themselves were produced in small quantities in the
> > > laboratories of I.G.Farben in the town of Hoechst, the same company
> > > that made "Zyklon-B", if you know what I mean?
> > > The allies (USA) were only later able to recall and discover this
> > > amazing "stealth" process and research by the time they got the
> > > supersonic SR-71 "Blackbird" flying in the second half of the 1960?s!
> > > I guess they finally figured that the supersonic jet needed some sort
> > > of stealth paint against radar. Same thing goes for the mysterious jet
> > > "U2" at the same time. (Ironball)
> > > According to some papers from the WW2 era it seems that I.G.Farben
> > > also had some help in developing this new breakthrough stealth
> > > research. Some of those companies were...The institute of Organic
> > > Chemistry in Danzig (prof-Klemm as already was mentioned), the Company
> > > Osram - "Studiesngesellschaft fur Elektrische Beleuchtung" in Berlin
> > > by a Doctor Friederich, the Laboratory of the Degussa Consortium,
> > > which is about 8 KM from the town of Konstanz near Bodensee, made by
> > > Prof.Fuchs and some others. Also the ceramic laboratories of the
> > > company Lutz und Co, in the town of Lauf/Pegnitz in Bavaria, by a
> > > Dr.Franz Rother, which is also the inventor of the "stealth" material
> > > used on the Type XXI U-Boats.
> > > Some other work was also done by the "Technische Hochschule in
> > > Stuttgard (Dr.Fricke) and in Praha (Prof.Huttig)
>
> > > Some interesting reports were later made by a Polish soldier who was
> > > working in a German airfield of Sorau (Zary) near Zielona Gora, just
> > > right after the German surrender, where it was reported seeing one
> > > aircraft being painted with some kind of "porous" kind of paint with
> > > some dark greyish colour left over by the Germans in a barrel...and it
> > > was found that the Storch was made almost invisible to radar!
>
> > > You will have to get Igor Witkowski?s book "The Truth about the
> > > Wunderwaffe" to read some more info on this and other secret research
> > > done by the Germans in WW2.
>
> > > ~ AHF, by MAX_theHitMan on 20 Mar 2005, 17:26
>
> > The Japanese worked on anti-radar coverings as well. See "Japanese
> > Anti-Radar Coverings" Report E-06 of the US Naval Technical Mission to
> > Japan at
> >http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/U...
> > orhttp://tinyurl.com/cdu8e7
> > There is no mention of any German-Japanese cooperation.
>
> Excelent store of reports there !
>
> --
> Meddle ye not in the Affairs of Dragons, for Thou art Crunchy and taste
> Goode with Ketchup.- Hide quoted text -
>
> - Show quoted text -
Yes, I'd love to find the equivalents for Germany on-line.
Joe