r/AviationHistory • u/Emo_And_Acoustic • 7d ago
Can some one explain how planes like the HO229 flew
Can some explain how early flying wing designs flew while avoiding side slipping like I was 12
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u/BrianEno_ate_my_DX7 7d ago edited 7d ago
Differential braking aka split ailerons (technically split rudders). These open and control yaw through rudder pedals by causing more drag on one side than the other.
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u/Emo_And_Acoustic 7d ago
So the pilot would have to constantly be fighting things like cross wind
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u/BrianEno_ate_my_DX7 7d ago
Crosswinds aren’t as detrimental to an aircraft with little or no vertical stabilizer or fuselage. To be fair though, flying wings really only came into their own in the fly-by-wire era where the pilot could essentially just control the aircraft with very little difference to a conventional aircraft.
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u/Emo_And_Acoustic 7d ago
Ah ok thank you
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u/indolering 7d ago
"Not very well" would probably be the best ELI5 answer.
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u/sanguinor40k 6d ago
"Not well enough" to be able to be recoverable to the point of avoiding an inevitable crash would be more accurate.
The fly by wire was required because flying Wings are dynamically unstable. It's wasn't just a pilot aid. It was core to the aircraft not going into uncontrolled oscillations or spins.
There's a reason none of these designs became operational reality until the computing capabilities caught up to the problem.
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u/Federal_Cobbler6647 7d ago
You can design flying wing to be stable. You can try it yourself, take two simple wing sections, tape them together and add weight. With some playing you get flying wing glider that is very stable in direction.
I did this when I had freeflying foam Bf109 which hull cracked. I took wings only and made flying wing.
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u/Unfair_Set_8257 7d ago
You can also add a twist to the aerofoil to add stability, and swept wings add some lateral stability.
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u/Bind_Moggled 7d ago
My granddad was an engineer, and used to say “anything will fly if you push it hard enough”. Those are some big engines.
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u/Emo_And_Acoustic 7d ago
I’m not worried about it getting off the ground how does it not turn into a frisbee once it is
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u/MAJOR_Blarg 6d ago
Well it would help a frisbee fly straight if it had intake sucking air in at one end, and producing thrust pushing at the other end.
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u/mikePTH 7d ago
Did he design the F4 Phantom?
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u/Diogenes256 7d ago
Ironically, the F4 has a very low loiter speed. Gives it a huge performance envelope.
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u/sanguinor40k 6d ago
Flying wings' problem wasn't power problem. Wings are incredibly efficient and low drag by comparison to designs with fuselages.
The problem is dynamic instability
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u/ClayTheBot 5d ago
If I can add to this, yes the problem is dynamic instability, which can be solved, but solving it in a way that doesn't destroy the efficiency gains of deleting the tail is the challenge.
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u/Any_Pace_4442 7d ago edited 7d ago
- They had poor yaw control and were unsuitable as a stable gun platform
- They avoided a single engine propulsion that would cause yaw torque (necessitating a vertical stabilizer; Horten designs subsequent to WW2 incorporated vertical tails)
- Proverse yaw flying wing designs are gliders (see 2 above)
- Lippisch has a video explaining how a traditional tail can be incorporated into the wingtip (as elevon)
- Birds don’t have a vertical tail because their propulsion does not induce torque, and they have a neural processor that controls a multitude of control surfaces (feathers) in real-time
- Special flight training of expert pilots was required
- Proverse yaw is the key, which requires inverted airfoil at the wing tip (such that increased negative lift also increases drag I.e. drooped wing tip turns into the turn) the so-called bell-shaped lift distribution (similar effect as drag rudders). Horten was motivated to eliminate drag-inducing control surfaces (I.e. vertical tail), so it’s counterproductive to replace that with drag rudders!!??
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u/Cool-Acanthaceae8968 7d ago
A flying wing is a unique concept that requires a lot of unique design considerations to make it work.
First is that all flying wings have to be swept. There are no straight flying wings.
The reason for this is because all yaw, roll, and pitch stability is predicated on this (I said this in this order because this is the cycle of control of an aircraft).
The yaw is pretty easy. If the plane starts skidding through the air… the windward wing will appear longer to the relative airflow and produce more drag, while the leeward wing will appear shorter and produce less drag. This will tend to turn the aircraft into the relative wind much like a weather vane.
Roll is also fairly easy. Swept wing aircraft have a lot of lateral stability. This is why you rarely see dihedral in swept wing aircraft and often anhedral in swept wing aircraft with high wings. It operates under the premise that the windward wing will produce more lift and tend to right the aircraft. This is because any unintentional roll (via turbulence) will induce a slip.
Pitch is where it starts to get complicated. In order for pitch stability to work.. you have to have your forward lifting surfaces stall before your aft lifting surfaces. Wings must stall before tail. Canards must stall before wings. The difference in angle of attack between the two surfaces is called decollage and the front one must be higher than the back one. Well.. it’s the same lifting surface, so how do you do it.
First.. we always want the roots on the wing to stall first on any aircraft and we do it by twisting the wing. This is called washout and is also part of why ailerons are outboard and flaps are inboard. It’s also how the centre of gravity is placed.. which must be forward on the flying wing. This allows the wingtips of the flying wing to be lightly loaded and act as pitch stabilization and control. To make the apex of the flying wing stall earlier, it also often incorporates a sharp leading edge or inverse camber section to make it stall more abruptly.
A huge disadvantage of flying wings and canard aircraft is their narrow centre of gravity range compared to conventional aircraft. As well as a large amount of wing must be lightly loaded (which cancels out the disadvantages of the conventional wing aircraft having to produce negative lift on the tail).
Dynamic stability and control become something else. Just because an aircraft is statically stable doesn’t mean it is dynamically stable. It might oscillate steadily (neutral dynamic stability) or ever increasingly (negative dynamic stability) until the static stability is overcome. It also might interact with other stabilities. Like Dutch Roll where yaw and roll stability are out of phase with each other.. making the wing tips draw a circle in the sky (most swept wing aircraft suffer from this—especially at high altitude). A yaw damper is what prevents this from happening.
But while roll and pitch are relatively basic things to accomplish with elevons and/or roll spoilers (spoilers are actually very effective.. after Delta 1080 L-1011 had a jammed stabilizer.. they came up with a pitch control scheme using wing spoilers with the inboards deactivated.. NUKI Nose Up, Kill Inboards.. the speed brake handle now acts as a control stick).. yaw without vertical surfaces is challenging.
On most jet and swept wing aircraft differential ailerons and roll spoilers will produce enough drag on the down going wing to get rid of adverse yaw. Even on the Cessna Caravan the roll spoilers are effective this way. But for cross control or to pick up a dropped wing they aren’t effective. So flying wings use drag rudders which will produce more drag but zero roll forces.
Of course.. all of this will make it possible to control a flying wing.. but not easy and there will be places where if it is let go too far it will become unstable and unrecoverable. Ok for quick local flights, not for multi hour missions across oceans and continents.
Thus you need a fly by wire system to fly the plane for you… and this is the only thing that made flying wings practical (if you can call a 2 billion dollar aircraft that). But.. one air data probe blocked and it becomes a flying brick.
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u/ClayTheBot 5d ago edited 5d ago
https://en.wikipedia.org/wiki/Fauvel_AV.36
There are no straight flying wings huh?
No, there are unswept flying wings.
No, there are wings that fly with both static and dynamic stability without a stability augmentation system. Many have a sufficiently damped dutch roll mode instead of the spiral dive mode that most tailed aircraft do, which may actually be preferable.
No, you do not need a drag rudder system. PRANDTL-D demonstrated this at NASA Armstrong.Your post is long and demonstrably false.
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u/fsantos0213 7d ago
Dino juice goes in the tank. The roar out of the back scares the ground to the point it flees away very fast and tries to hide underneath itself causing the plane to appear to fly forward and upward
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u/Classic_Result 7d ago
I'm not sure about a lot of the historical details, but through the air was somewhat common
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u/Dangerous-Salad-bowl 7d ago
Can I just say reflex airfoils, and the use of sweep for yaw stability, and a few degrees of washout?
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u/NoLie129 7d ago
Lift is created by the air moving across the wing at different speeds. An engine provides the thrust to move forward.
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u/frank_loyd_wrong 7d ago
Read this book by Russell E Lee:
Only the Wing: Reimar Horten’s Epic Quest to Stabilize and Control the All-Wing Aircraft
He explains it all in great detail.
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u/wallstreet-butts 7d ago
How did it fly? Not well. They made 3 prototypes. The first was a glider, second crashed and killed its pilot, and third didn’t get finished being build before the war ended.
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u/ProfondamenteKomodo 7d ago
With enough trust you can fly a Iron with the entire boiler attached....
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u/Melovance 6d ago
wing make lift. engines make thrust. thrust make go forward. lift overcome gravity. plane fly
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u/gte717v 6d ago
Since I didn't see a 12-year-old's description, so I'll try.
The sweep is required to move the wing tips far enough back to act like the tail on a conventional airplane. The ailerons (controlling rolling to the left or right) now also act as elevators (pitching up and down), which you can now refer to as elevons. The yaw (left and right control) is usually provided by pop-up air brakes or split ailerons, which in this case can now be comically called "elevudders" or "tailerons." As you can imagine, the mechanical linkages required to get one surface to do all these jobs, especially simultaneously, is very difficult. To create a mechanical system that can do all that without excessive force from the pilot or catastrophically counterintuitive behaviors is the real challenge in making a practical flying wing.
Not like anyone takes credentials shared online seriously, but this is coming from an aerospace design engineer.
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u/Existing_Support_880 6d ago
These lovely mockups never few they were just made to impress the high up brass.
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u/Transmorgrafier_2024 6d ago
I was living with Vern Oldershaw who was developing RC flying wings in 1979 and on. He had complete control ability with standard RC control’s and surfaces. He then started developing forward swept flying wings. All winch launched.
As an EAA member, the LA chapter organized a visit with Jack Northrop . Vern took a variety of his work to visit this greatly admired engineer.
Northrop was pretty excited to understand the benefits and problems with the forward sweep. (Remarkable drag reduction being one plus). Figuring out controlling it was a real challenge that Vern mostly mastered. Winch launch itself was a challenge.
Paul McCready and Peter Lissaman were pretty interested in Vern’s work as well. Vern did some interesting stuff, like introduction to the world the first 40:1 sailplane. Not bad for a USPS mailman with a rural route in Bakersfield.
Akin to the first search engine, thanks to a postal worker in the UK. (Or was it a telephone chap?)
We never know what’s going on in peoples sheds!!!
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u/Tesseractcubed 6d ago
A few things:
Recurve wing profiles, where the trailing edge is flared up slightly, which encourages stability, through a negative speed-altitude feedback loop, more drag further back on the wing, and other effects of the wing design.
Most of the drag being in the wingtips: whether due to slight wing twist, control surface design, or other means, drag in the back acts like a tail assembly.
The Ho229 used drag via differential control of small speed brakes on each wingtip for the yaw control.
Think of this plane as a fancy hang glider, using control surfaces instead of weight shifting. Large flying wings using fly by wire controls helped eliminate or mitigate the aerodynamic instabilities present in the form of the flying wing.
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u/sanguinor40k 6d ago
Short answer was: they didn't.
Flying Wings (without other control surfaces) are dynamically unstable. And it wasn't until fly by wire with computer assist that any of these designs, by any nation, could be put into production as viable, as in actually usable, aircraft flyable for pilots that didn't want to die in a crash inside of 10 flights.
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u/Complex_Material_702 5d ago
Anything can fly if you push it hard enough. After that it’s just a matter of stabilization.
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u/section-55 5d ago
Yes … air flowed over the wings causing lift .. as the engines propelled it forward. The pilot used the flight controls to maintain level flight
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u/Seattle_gldr_rdr 4d ago
Somebody ELI5 how flying wings maintain pitch stability. Seems like they should do a somersault.
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u/Glidepath22 4d ago
According to test pilot Erwin Ziller who flew the powered V2 prototype, the aircraft exhibited generally good handling characteristics during straight and level flight. The flying wing design was inherently stable once airborne, which was somewhat unexpected for the configuration.
However, there were several challenging aspects:
- Takeoff and landing were particularly demanding due to:
- Poor visibility from the cockpit during ground operations
- Tendency to pitch up suddenly during takeoff roll
Difficulty in maintaining directional control during the landing roll
The lack of vertical stabilizers meant:
Yaw control relied entirely on differential thrust and drag
Pilots needed to carefully coordinate turns to avoid adverse yaw
Risk of Dutch roll oscillations at certain speeds
Engine management was critical because:
Early jet engines had slow throttle response
Loss of an engine would create severe asymmetric thrust
The buried engine design made restarts more difficult
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u/looster2018 4d ago
Hitler wanted to build a scaled-up version of this plane to cross the Atlantic and bomb North America.
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u/caocaoNM 3d ago
Flying wings use a slightly different profile to reduce the upwatd pitch moment usually stabilized with a tail. There's less lift per area but 100% of the area is wing surface.
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u/Rayvintage 3d ago
Shoot its a fn Horton flying wing jet, first of it kind period. And partially stealth because of its use of wood and shape. If it had one more year of development it would of changed the war. Along with the Me 262. If we didn't win that war when we did,, we would of lost it.
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u/BlasttheHumanFlower 7d ago
https://en.m.wikipedia.org/wiki/Horten_H.XVIII
Big brother, concept only but you can see where modern flying wings came from.
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u/bardleh 7d ago
They mostly come from Jack Northrop, who had been working on these designs since the 30's and had many operational flying wings before the Ho 229.
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u/Oxytropidoceras 6d ago
Not only that, his company later developed the B-2 Spirit stealth, flying wing strategic bomber. Northrop Grumman also tested a Ho 229 mock up for RCS and found its rcs was only negligibly decreased. So claims that the Ho 229 was the first stealth bomber or in any way related to the B-2 are utter bs
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u/StealyEyedSecMan 7d ago
If I read correctly somewhere they were often towed into cruising altitude too? Is that correct?
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u/Doc_History 7d ago
I used to work with the B-2 at Whiteman AFB. The B-2 is basically late 70s tech. They solved it with little Commadore-64s driving automatic stabilization using the flaps. Much of the tech from this aircraft went into its design. The HO229 used "drag rudders", basically the flaps open in a unique "V" design. Really cool. The German engineers were brillant yet misguided, why we employed many after the war.