Hitler's Stealth Fighter

[Gixxerman]

Recall that the B-49 flying back in towards east coast radar was not detected until the 'plane was almost directly overhead

Sorry, I know this is OT but that is something I'd heard before and it always made me wonder about the Avro Vulcan and whether it's 'almost a flying wing' shape lent it any stealth qualities or not.

 

[Matt308]

As to the Horten IX, I forgot to say that I did read that in certain manoeuvres - Dutch roll maybe? - the aircraft could become unstable and difficult for the pilot to control. So a flying wing would work well for a strategic bomber but not for an aircraft which needs to perform a lot of acrobatic manoeuvres. Until computurized fly by wire was developed. So F-117.


Kris

I think it was high AOA stall characteristics that were tricky for the all wing design prior to flight control computers.

 

[johnbr]

I read that the Ho 229 was very hard to stall.

 

[Civettone]

Yeah that could be. Can you give some more info on that, Matt? And does it simply mean that a glider wing cannot climb as steep as another aircraft?

And now I think about it, it was the tailless B&V designs with downturned wingtips which suffered from Dutch roll.

Kris

 

[Civettone]

I was looking up some more stuff. Could it be that another problem was yaw stability?

from Why aren't there flying wing passenger/freight airplanes? - Straight Dope Message Board

he load is applied at "hang point" on the keel, at or at most a few inches below the lower wing surface. (assuming a lower surface) Most are reasonably stable when the pilot releases the control bar, and is hanging free. The airframe sees this as a point load at the hang point.

Anhedral is required in most flex wings to reduce roll stability and permit manageable control forces. This accomplished by designing the wing to fly in a nose high attitude, causing the sweep of the wing planform to translate to anhedral.

Roll stability in a flying wing is no different than conventional aircraft. Conventional aircraft have no surfaces beside the wing that influance roll stability. There is no reason a flying wing can't incorporate dihedral, though most don't require it. Roll instability is normally slow, tame, and not difficult for a pilot to manage.

Pitch stability in a flying wing is another kettle of fish. For stability, the CG needs to be ahead of the wings center of lift, which produces a nose down pitching moment. This must be countered, and conventional airplanes do this with upward force generated by the horizontal stabilizer. By placing the H. stab well aft, not much downward force is needed (long lever) so efficiency is pretty good.

Lacking the H. stab, pitch stability in a flying wing is accomplished by reflexing the trailing edge and/or washout in swept wing tips. A forward swept wing can use a bit of washin, working as a canard. I'm pretty sure the Genesis sailplane does this. The Genesis does have a small H. stab. This was a late addition to the design. It is much smaller and closer to the CG. than conventional gliders and is not the only source of pitch stability.

Because the trailing edge, or wingtips are not very far aft of the CG, large forces are required, and this reduces the efficiency of the wing. To improve this, the CG is moved aft, which reduces stability. It is a fussy bit of compromising, but as I stated, the Horton Brothers had gotten pretty good at this back in the early 1930s. Good enough to build contest winning gliders and Nazi medal winning jets which of course didn't need yet-to-be-invented computers for stability augmentation. The brothers routinely flew the gliders yet managed to life until mundane deaths in the 1990s.

It is simply not true that aerodynamically stable flying wings flyable by ordinary pilots can't be built. It has been done more or less routinely for many decades.

By reducing aerodynamic stability, and restoring it with electronic augmentation, it is possible to improve the efficiency and maneuverability, or reduce the radar signature of nearly any aircraft configuration. This is not unique to flying wings. The fact that well know contemporary flying wing designs use computerized stability augmentation does not mean they can't be made controllable without such.

and about AoA:
If the wing's CL is ahead of the CG, then it tends to pitch the nose up increasing the angle of attack (AOA)which causes more lift, which exacerbates the situation.

In a stable, conventional airplane, any excess lift from the wing will tend to pitch the nose down, decreasing the AOA, relieving the excess lift, and will also tend to increase the negative AOA of the H stab which will tend to restore the AOA that existed prior to the disturbance.

Extending your train of thought: Because the wing and H stab normally operate with opposing incidence angles, the effect of AOA is that the CL of the airplane as a whole moves in response to AOA changes, and that movement tends to produce stable flight in pitch.

Still need to reread this a couple times though
Kris

 

[bobbysocks]

You just reminded me of one of the interesting vodka ads on UK TV recently.
It's a CGI film of all the old wrecks coming out of the sea and had a Lanc and Hurricane leaving the depts.

Here-
View: https://www.youtube.com/watch?v=-iXwzBvdrIY

It would make restorations a lot easier more numerous!

that is a cool commercial! any ac sitting in salt that long would be in very sad shape. now if you could find one in cold fresh water...that might be worth the effort.

 

[The Basket]

The narration of the programme was a mess.

Saying that the 229 was a stealth design without putting any evidence that it was designed thus. The Hortens lived until quite recently...and was interviewed many times...didnt they say anything???

Horten were the flying wing kings and then say Jack Northrop also made flying wings.

20% reduction in radar cross section but then saying low flying would have same effect.

Then destroying a radar chain home station with cannon fire...

Mass of contradiction nonsense.

Loved the model they made and it looked amazing on the pole thingy...absolute sinister.

 

[tail end charlie]

Well quite.
It did.
But first 2 prototypes were lost in crashes, but not before the performance was seen to be impressive.
It's the 3rd unflown complete prototype that the Americans took away and have in mothballs.

Somethings make me laugh, losing the first 2 in crashes makes me think of flying coffins not a game chaning aeroplane. As I remember the British flying wing was the first successful use of an ejector seat, which says a lot. Flying wings were years from being operational, it is like theorising what any force could have done with a few sqadrons of Mig 21s Hawker hunters Super Sabres etc.

The biggest advantage of the german wing seemed to me to be it didnt have propellors, how did it compare to a 262 or meteor on radar profile wasnt discussed. When it may almost have been able to fly 1944 Germany was fighting in Normandy could it fly from Germany? and having knocked out a radar tower then what?

 

[NZTyphoon]

Sorry, I know this is OT but that is something I'd heard before and it always made me wonder about the Avro Vulcan and whether it's 'almost a flying wing' shape lent it any stealth qualities or not.

The Vulcan was reasonably "stealthy" , in spite of the huge air intakes at the wingroots; if the radar can see the front fans of the engines they will show up like flat plates, exponentially increasing the radar cross section (RCS) of a jet aircraft. However, the Vulcan's engines were "buried" deep within the wingroots, with curved air intakes which didn't allow radar to pick up the engines. The large tailfin did, however, increase the RCS.

The RCS of the B-52 is very large (about 100 sq. m.), mainly because the faces of its eight engines looked like eight large flat plates. The prize for the greatest RCS of any combat aircraft still flying goes to the Tu-95 "Bear".

Incidentally the RAH-66 Comanche which has been canned, was one of the first stealth helicopters.

 

[Civettone]

Are there other stealth helicopters?


Kris

 

[Gixxerman]

Somethings make me laugh, losing the first 2 in crashes makes me think of flying coffins not a game chaning aeroplane.

In fairness the info I have says that the 1st one was lost after an accident "when the pilot forgot to retract a long inciodence pole before landing".
The 2nd is said to have been lost on approach after the sudden failure of one of the engines.

As I remember the British flying wing was the first successful use of an ejector seat, which says a lot.

I always thought it was a German.
A few German aircraft towards the end of the war had them (Heinkel He219, Heinket He162, Dornier Do335).
Wiki rekons it was a German (ref given) -
One of the He 280 test pilots, Helmut Schenk, became the first person to escape from a stricken aircraft with an ejection seat on 13 January 1942 after his control surfaces iced up and became inoperable.
Ejection seat - Wikipedia, the free encyclopedia

Flying wings were years from being operational, it is like theorising what any force could have done with a few sqadrons of Mig 21s Hawker hunters Super Sabres etc.

I'm pretty sure I've read before that it took fly-by-wire to iron out all the kinks in operating a flying wing without worrying about it's areas of, er, 'difficulty'.

The biggest advantage of the german wing seemed to me to be it didnt have propellors, how did it compare to a 262 or meteor on radar profile wasnt discussed.

The data I've seen in things like 'Warplanes of the Luftwaffe' or 'Hitler's Luftwaffe' give it a very high estimated speed (977kph/607mph @ 12,000m/39,370ft).
They say a measured speed of 800kph/497mph had been reached in testing before the accidents put a stop to any further work.
It was stressed to 7g, had a climb rate of 1320,/4,330ft per min, a range of 1900km/1180mls and a ceiling of 16,000m/52,493ft.
It could be armed with 2 x 30,, mk108's and 2 x 1000kg bombs.
Impressive numbers, if true.

When it may almost have been able to fly 1944 Germany was fighting in Normandy could it fly from Germany? and having knocked out a radar tower then what?

Yeah but that's only the fighter/fighter-bomber.
The Hortens apparantly convinced Goering to let them build a strategic trans-atlantic bomber.
The Horten HoVIII/HoXVIII B-1.

You should see that History Channel show.
That one has Adolph in the dying embers of WW2 (if it had just lasted 6mth longer or so) nuking New York,
well 'radiologically attacking NY at the very least.
Phew, it's nerve-wracking stuff. Or perhaps not.

The designs themselves were interesting and for their day as advanced as anything out there (but hardly completely unique).
But these programs always end up being so annoyingly superficial and sensationalist.
The idea that a one-off aircraft, free of all testing and study in tactics, training, operations and general necessary support all the rest could do anything much against an opposition overwhelmingly equipped with weapons systems that were properly tested and trained for and operated in the full knowledge of how best to use them and properly supported at every stage is just silly.
I guess it injects some sort of drama into a long-past historic episode for the lay-man but surely the truth is just as interesting?

 

[DerAdlerIstGelandet]

Somethings make me laugh, losing the first 2 in crashes makes me think of flying coffins not a game chaning aeroplane.

Many first prototype aircraft have been lost from many countries. I don't think that the design of an aircraft should be based on that. Certainly not during the trial and error phases. I agree that technology was not quite there yet however...

As I remember the British flying wing was the first successful use of an ejector seat, which says a lot.

That is wrong.

The first true ejection seats were built by the Germans and the Swedish. The first operational ejection seat was used in the Heinkel He 280 and installed in 1940. Helmut Schenk became the first pilot to eject from a disabled aircraft in 1942. The first operational aircraft to use ejection seats was the He 219 in 1942.

The Swedish invented the first "gunpowder" ejection seat in 1943 and in 1944 Heinkel used the first "explosive cartridge" ejection seat with the He 162.

The British one you are talking about was only the "first" emergency ejection by a British Pilot and it was 1949. The British began to research ejection seats before the Germans did however, the first British tests were not conducted until 1945.

If you really want to be technical however there were rudimentary and simple ejection devices that were tested before everyone else back in the 1920s.

 

[Milosh]

Somethings make me laugh, losing the first 2 in crashes makes me think of flying coffins not a game chaning aeroplane.

Many prototype a/c crashed. The P-47 had to be entirely re-designed, for example. The XP-80 certainly was not without it problems.

The first flight of the XP-80 took place on January 8, 1944 with test pilot Milo Burcham at the controls. The first flight had to be cut short after only five minutes because of undercarriage retraction failure and the pilot's concern over boosted aileron sensitivity. These problems were quickly fixed. Subsequent test flights reached a top speed of 502 mph at 20,480 feet, the XP-80 becoming the first USAAF aircraft to exceed 500 mph in level flight. However, the flight tests also disclosed a number of problems including bad stall and spin characteristics, an excessively-high stick force, unsatisfactory fuel management systems, and poor engine reliability and performance. At low speeds, it had a tendency to stall and roll sharply to the right with little or no warning. These problems were addressed one-by-one. The original blunt-tipped wing and tail surfaces were replaced with rounded tips after the fifth flight, and sharp leading edge fillets were added at the wing roots. The tailplane incidence was increased by 1 1/2 degrees.

The Ho-9 V1 did not have engines and was flown successfully several times.

Ziller flew the Ho-9 V2 for 30 minutes and was pleased with the handling of the a/c. It was at the end of the 2cd un-authorized flight that the a/c crashed after loosing an engine on the landing approach. As the Ho-7 had been flown successfully on a single engine, it was concluded that the crash was due to pilot error.

The Monogram Close-Up #12 is worth reading.

 

[Colin1]

In fairness the info I have says that the 1st one was lost after an accident "when the pilot forgot to retract a long incidence pole before landing"
The 2nd is said to have been lost on approach after the sudden failure of one of the engines.

Any talk of accidents to prototype aircraft damning them as failures is nonsense. The first P-51 was lost when test pilot Paul Balfour put NA-73X over on its back. The Typhoon test pilots recorded, on average, 11 precautionary early landings due to faults out of every 20 take-offs. The P-47 introduced the aeronautical world to the problems of high altitude on ignition systems and oil cavitation. Anything novel is going to come with its own bundle of unknowns. In the world of air test that usually manifests itself as something that can kill you.

A few German aircraft towards the end of the war had them (Heinkel He219, Heinket He162, Dornier Do335)

Getting out of an He162 without an ejection seat must have been a barrel of laughs with that air intake directly in your line of egress

 

[DerAdlerIstGelandet]

Any talk of accidents to prototype aircraft damning them as failures is nonsense. The first P-51 was lost when test pilot Paul Balfour put NA-73X over on its back. The Typhoon test pilots recorded, on average, 11 precautionary early landings due to faults out of every 20 take-offs. The P-47 introduced the aeronautical world to the problems of high altitude on ignition systems and oil cavitation. Anything novel is going to come with its own bundle of unknowns. In the world of air test that usually manifests itself as something that can kill you.

Ditto and many good examples.

 

[Gixxerman]

Getting out of an He162 without an ejection seat must have been a barrel of laughs with that air intake directly in your line of egress

Too true.
I am reminded of this vid I saw while back, the guy recovered ok but f*** me what a lucky escape!


View: https://www.youtube.com/watch?v=GF3Iz7b95-8

To have your bang seat fail attempt a 'normal' bail-out would be a real lottery (not forgetting 2 fins to have to avoid too).

 

[Colin1]

To have your bang seat fail attempt a 'normal' bail-out would be a real lottery (not forgetting 2 fins to have to avoid too).

Diced then sliced...

 

[tail end charlie]

That is wrong.
.

LOL adler I missed out a "british"

I wrote
As I remember the British flying wing was the first successful use of an ejector seat, which says a lot.
I should have written
As I remember the British flying wing was the first successful british use of an ejector seat, which says a lot.

There had been many pilot losses in meteors in its early days but the flying wing was fitted with an ejector seat before them, I think the designers knew they were on very dodgy ground to start with.

 

[NZTyphoon]

Are there other stealth helicopters?


Kris

Nope - that should read to date the only stealth helicopter except for Blue Thunder which had a "whisper" mode...

Pre-war the British experimented, not very successfully, with the Westland-Hill Pterodactyl series. A WW2 design which led to post-war Northrop flying wing XB-35 and YP-49s - which ultimately led to the B-2A, was the Northrop XP-56.

 

[Colin1]

Nope - that should read to date the only stealth helicopter except for Blue Thunder which had a "whisper" mode...

Umm, hang on a minute
wasn't Airwolf a bit clever as well?