the germans had the first stealth fighter!

[Angus]

I always thought the mossie was quite hard to catch on radar. Even if radar beams would bounce of internal metal things, the whole size of those are only a fraction of the whole aircraft size.
I would love to see some history related information about this. Anyone:confused:

[BUG_EAF322]

that's why i said hard to find
even the f117 got a radar profile

u can even see a flock off birds on the screen

I have been in the army anti aircraft unit
on the dutch version off the gepard so i know a little too

[MiloMorai]

State of the art radar in the early 1940's is NO WAY near what radar is capable of doing to-day. Any wooden a/c would have been hard to 'see'.

ps. the Hortens had been flying  glider and low powered 'wings' with no control problems befor the Ho9.

[illo]

Ho IX v-2 (second prototype)

Stall speed
150 km/h
 
Landing speed
130 km/h
 
Cruise speed
900 km/h
 
Maximum speed (horizontal)
960 km/h
 
Maximum speed
1000 km/h

Empty weight
4844 kg

Maximum weight
6876 kg

Wing loading
130 kg/m2

The Ho IX Twin Jet In a speech before representatives of the aircraft industry, Reichsmarshall Goering had announced that no new contracts would be given, unless the proposed aircraft could carry 1000 kg bombs, fly 1000 km /h, and have a penetration depth of 1000 km; penetration depth being defined as the total range.

 The Fighter Division requested that the aircraft also be fitted with 30 mm machine guns, something that would lessen the machine's efficiency as a bomber.

 We started drawing and calculating without a contract. Our plan was to build two full size prototypes. The initial penetration depth would only be 800 km, since the fuel proof glue necessary for the full wet wing, was not yet available. On the other hand, the smaller fuel load allowed a doubling of the bomb load, so we went ahead and submitted our proposal.

A contract was awarded with the demand that the first flight be made in six months! Since the jet engine was not yet ready, the first machine would be a glider. The previously deactivated Air Force Command IX was reactivated, and ordered to proceed with the project. Fortunately, the preliminary work that we did without a contract, put us sufficiently ahead, so the six month deadline locked feasible.

 There were several reasons for choosing wood as the building material. Duraluminum required more energy to produce; over 3000 KWH, versus less than 3 KWH for wood per ton. The required labor for aluminum production was also much higher; 5000 hr/ton against 200 hr/ton for wood. In addition, aural was difficult to find, and skilled sheet metal workers in short supply. Unskilled workers could easier be trained to work with wood.

 Typically, a nose rib was built from a triangular piece of spruce, sandwiched between two plywood sheets, all scrap wood. Production time: 10 minutes. After the glue dried, the rib was simply roused out along a master template in less that 5 minutes. The rest of the wing was built in a similar crude fashion, to pave the way for mass production by unskilled workers.

 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.

 Finally, should a 20 mm shell explode inside the wing, a relatively harmless hole would result, whereas a metal wing would balloon out and lose its lift.

 The H IX wing was designed with 3 geometric and 1.5 aerodynamic twist, to give it the desired bell shaped lift distribution with all controls neutral. The Frise-nose on the elevons had proven to be unsatisfactory, so we decided to use blunt nose elevons instead. The sharply enlarged wing root chord served mainly to eliminate the middle-effect. The maximum thickness line (T-4 line) therefore made a sharp bend in the middle, which resulted in the characteristic pointed tail. As this would affect stability, a test aircraft with large aspect ratio, that had the control surface far outside the test area, was needed. The H Vl would serve this purpose, while other preliminary tests were made with a H II and a H III.

 The H IX V-1 took off right on schedule on March 1, 1944 in Gottingen. The small He 45 towplane barely got off the ground, so test pilot Scheidhauer released, and landed straight ahead, after only a short hop. Five days later, he was off again on a snow covered runway behind an infinitely more powerful He 111. He released at 12000 feet, made an uneventful glide back to the airport, then faced problems during landing when the drag chute did not function. As the end of the runway approached, he retracted the nose wheel, and skidded to a stop with only minor damage.

 The second aircraft, scheduled to fly three months later, was awaiting its engines, promised in March. Several weeks passed, and then... Disaster!

The engines arrived with an accessory section added to the case, making the cross section oval, and the diameter 20 cm greater! No one had bothered to inform us! Now, just six weeks before the first flight, we were faced with the problem of fitting an 80 cm engine into an aircraft with a 60 cm hole in the spar! It meant that the wing would have to be made thicker.

To maintain the aerodynamic qualities of our design, we would have to increase the span from 16 to 21.3 meters, and the wing area from 42 m2 to 75 m2. Such an aircraft would never reach the targeted performance, even with higher engine thrust. We choose instead to do the best we could with patchwork modifications. The wings remained the same. Another root rib was added 40 cm outside the original, making the center section 0.8 m wider. The new airfoil was 13% thicker than before, and the bend in the T-4 line became much larger. The thicker center section lowered the critical Mach number to 0.75, or a maximum speed of 920 km/in.

 The ratio of movement between the control column and the elevons could be reduced to by the pilot for high speed flight. A small high speed drag rudder was supplemented by a larger one that deployed after the smaller was fully extended. Many parts were scrounged from other aircraft left at the test facility in Gottingen. The nose wheel, for instance, came from the tail wheel of a He 177 heavy bomber. We were even able to use the strut and retract cylinder!

 The men of Air Force Command IX did their utmost to complete the aircraft before the end of 1944, sometimes working more than 90 hours per week.

I remember that Lt. Erwin Ziller made the first flight about December 18th, 1944, but his log book indicates that the first flight occurred on February 2nd., 1945. I am quite sure the first flight of the H IX was also his first in a jet. Our leaders had little concern for such risks.

 Satisfied with the initial flight, the Air ministry ordered 40 aircraft to be built by the Goetha Waggonfabrik under the designation 8 -229.

 It appears that the H IX V-2 had flown three or four times before tragedy struck on February 18th. The many versions of the story have a few things in common. The weather was overcast, the ground soft and muddy. The visibility marginal for a test flight, as Lt. Ziller took off, retracted the gear and disappeared. We received a report that one engine had failed, and that the H IX was returning to Oranienburg. Due to the low ceiling, a shallow approach to the airport was initiated. Since the hydraulic pump was on the dead engine, gear and flaps were extended by the emergency compressed air system. Once down, they could no. be retracted. To maintain his glide slope, Lt. Ziller added power. to overcome the extra drag, and found to his horror that he could" no longer maintain directional control; the fully developed drag rudder unable to overcome the asymmetrical thrust. Rather than lose control, he retarded the throttle to land short of the runway. The aircraft touched down in a field, slid into an embankment and flipped over, crushing its pilot.

 The Third US Army Corps reached the Goetha plant on April 14th 1945. Here they found the H IX V-3 intact and nearly completed, and also the V-4, V-5 and V-6 in various stages of completion. The Ninth US Armored Division found the H IX V-1 in good condition near Leipzig. Its fate is unknown.

 The H IX V-3 was later shipped to USA, and is now in the Smithsonian collection, awaiting restoration.

Go 229


Ho IX (v3) with wings removed.

[hazed-]

Do any of you know anything about the 1940's radar?

or modern day for that matter?


sheesh

[Puck]

Originally posted by hazed-
Do any of you know anything about the 1940's radar?

or modern day for that matter?


sheesh

Well.  Actually, a long time ago in a lifetime far, far away the Navy made me learn about radar before it would let me learn about neutrons.  I worked on AN/SPS-10 serial number 1 at various times.  As I recall it was built sometime in the late 1940s.

I've also played around with the SPS-40, 48, and the Mk 51 and 60 directors.

Mostly I made hot water, though.

Ok, I do know a bit about radar in the 1930s/40s.  Took a pretty skilled operator to make sense of the o-scope displays back then.

[midnight Target]

Luftwabbles!

The 229 was a ripoff of a Northrop design. Sheesh.

[Sabre]

Well, does a MS degree in Low Obervables technology count as knowing something about radar?  My thesis was validation of radar cross section (RCS) prediction code, basically running prediction for different shapes/materials/frequencies and comparing these to measurements done in anechoic chambers.  Based on my experience and training, my thoughts are that the Mossie would possibly have a somewhat smaller RCS at specular angles to large surfaces (i.e. direct reflections off sides/top/bottom) but would probably have a larger RCS at anges not perpendicular to major skin areas like the fuselage and wings.  Again remember that the Mossie had wooken skin and some of the structure, but was chock-full of ugly (from a radar perspective) boxes, bracing, wiring, cable, engines, fuel tanks that reflect radar even worse that a smoth metal skin.  

Consider from the front.  The propellors look like giant 3-meter diameter metal plates, whether the rest of the plane is metal or not.  If the radar wave was vertically polarized, metal wings might not show up at all on these old radar sets.  Wooden wings being only semi-opaque, the fuel tanks and other metal bracing or other stuff that would normally be hidden will light up on radar like a christmas tree.  It's very hard to explain without drawing some pictures and getting into Electromagnetic theory.  Anyway, just my opinion.  And moot, since we have no true radar modeling in AH.  The basic assumption of AH is that if it's within the specified range of the radar, it will show up on radar.

[HoHun]

Hi Sabre,

interesting analysis! How would you judge the Ho 229's radar signature by comparison?

From what I've read, the Germans actually employed radar-absorbent materials in combat for the first time - not to hide aircraft, though, but to hide submarine snorkels :-)

Regards,

Henning (HoHun)

[faminz]

Originally posted by tofri
Oh, thats reminds me on "The Secret Weapons of the Luftwaffe".

aaah SWOTL!!!  A great game... perhaps we could have an AH arena for wierd and wonderful 'what could have been planes', a bit like the WWII:1946 addon to 'Aces over the Pacific'.

there we had:
J7W Shinden
F7F Tigercat
F8F Bearcat
P-80 Shooting Star
F2G-2 Corsair
Nakajima Kikka
Mitsubishi Ki-83

I still have the box with the 1.2Mb floppy!!!

SWOTL had:
The usual vanilla stuff like 109s, FWs, spits, ponies and jugs
plus
Me163 Komet
Me262A-1a and 2a
Gotha Go 229A-0
He162
P80
Do-335

you can prolly still get both games via an abandonware site but theyre pretty dated and would need slowing down nowadays....

aaah... great days of early flight sims!!!

[minus]

hmmm about radars ,  even invisible  F 117 or B 2 are not so invisible , all it depend on freqency, ! it was the same  at 1940 or today , the bigest plague  for the modern stealth planes  are the pasive echo signatures , like  FM AM radio emision or TV  broadband emision can make them detectable    , they built from materials counter military detection  , and hard to find a material who what not reflect any kind of emision , the perfect stealth is not realy posible

[Sabre]

HoHun: Well, the Ho 229 potentially could have a pretty small RCS by comparison with other fighters of its day.  However, it should be noted that a great deal of its wings and fusilage were wood covered, but with (as I recall) a metal bracing and some ribbing and spars.  If they painted it with metalic based paint, put a "egg-crate" screen over the engine inlets similar to the 117 uses, and sputtered gold onto the canopy to make it radar reflecting, it would be very stealthly indeed by comparison to other aircraft of like size and era.  The lack of propellors, and the engines being buried in the wings really cuts the RCS down, so long as those engines are not visible on radar because of transparent aircraft skin around them.

I've read about the use of RAM on German U-boat schnorkles, to try to defeat sea-search radar.  It was not particularly successful.  The problem with RAM is, it is frequency specific, and must be a good 5 wavelengths or more in depth to absorbe an appreciable amount of incident E-mag energy.  So while it did reduce the signature somewhat, the newer radars deployed against them were still sensitive enough to pick it up at fairly decent ranges.  In other words, it reduced detection range a bit, but not enough to protect the sub in most cases.  The Allies simply tightened their search patterns a bit more to account for the reduced detection range.  Using different frequencies also foiled the RAM coatings.

What Minus says is true.  Even the vaunted B2 and F117 are not invisible to all forms of E-M transmissions.  The problem is not just detecting the presence of a stealth aircraft, but to track it and guide a weapon to a successful intercept.  Even during the Gulf War, the Iraqi often knew "something" was up there.  But it was elusive enough that they couldn't track and engage the F117's.  They were thus reduced to blindly throwing up unguided flak in the vain hope of catching an enemy plane with the "golden BB."