DISCUSSION ON BUILDING NEW GENERATION PLANES

[L Edge]

In the future, a majority of military planes (commercial as well) will be rudderless. So now the problems of yaw will need to be addressed.

Possible solutions FOR SINGLE AND MULTI EDF's:

1) DIFFERENTIAL Thrust for multi engine planes to handle yaw.
2) THRUST VECTORING Nozzle for single engine EDF to handle yaw.
3) Incorporate a gyro system to resolute any time a surface control has movement.
4) ?

Does differential thrust (2 props) work with a gyro to handle yaw?

As you can see, a flat sheet can fly with limited wind does work. Wind, not so good.

Using a thrust vectoring nozzle work without a gyro and only 2 servos work? You bet, here is how it was done for a X-47B.

https://forum.flitetest.com/index.p...servos-tv-nozzle-and-no-vertical-stabs.58012/

Don't know if works for other designs. Tough to duplicate.

So, for anybody who attempts to try(hope you will share with others) the easiest way is to use a gyro system.

Somebody is going to get it to work so it can be duplicated by others.

 

[L Edge]

A couple of years ago I ended up with a Spektrum 636 AS3X programable gyro that I could not even get to upload. Stuffed it in a draw and found it and retried programming it on a 3D foam model I had. I set up 3 modes and went to town on it.

If you understand gyros(rate gain,head holding gain, priority, absolute vrs relative) as well as setting up your own D/R, expo for 3 flight modes, you have the ability to set it up the way you like to fly. No work is done on the transmitter!!! Export the file in your computer and you can use/make another program that suits your flying.

If you explored a rudderless model, you know that if you move a control, you most likely change forces in one or more axis, so a gyro would could adjust for it if you are allowed to incorporate a mixing program. Guess what, does your gyro allow for that?, This one does.

So far, I have not seen a future fighter model attempted by any designer that flies. Perhaps someone will go for it. Right now, I am wrapped up with a VTOL and a 45 degree Forward Swept Wing (no fuse at all) using the AS3X.

 

[FoamyDM]

4) Prandlt-D wing type configuration

 

[L Edge]

4) Prandlt-D wing type configuration

Do you know of foam built military models that are flying?
Interested in site to see how how they accomplished the wing config to keep its shape.

 

[JasonK]

Do you know of foam built military models that are flying?
Interested in site to see how how they accomplished the wing config to keep its shape.

the prandlt-d was a research design

https://duckduckgo.com/?q=Prandlt-D+wing

 

[L Edge]

the prandlt-d was a research design

https://duckduckgo.com/?q=Prandlt-D+wing

Again, looking if anybody used it on a future fighter? Aware of design. Now, future designs want to incorporate stealth and I don't know if that type of wing will allow it. By removing the vertical 1 or 2 rudders, drag is reduced up to 20 %.

 

[JasonK]

Again, looking if anybody used it on a future fighter? Aware of design. Now, future designs want to incorporate stealth and I don't know if that type of wing will allow it. By removing the vertical 1 or 2 rudders, drag is reduced up to 20 %.

notice the wing span on that, I struggle with it showing up in most military designs because of that. Perhapse in some long range stealth bomber/spy-plane type thing (that you won't hear about until it isn't in primary service or reason for the gov't to think other gov't might not know about it).

navy planes have some rather strict wing spawn related issues to fit on those ships/boats. Airforce not as much, but high wing spans does limit what runways it could use. Also, while the prandlt-d is great at efficient, doesn't mean it is great at maneuverability, so it seems mostly like something that would be used on something with long range needs primarily.

 

[leaded50]

here is a pic of the Prandtle M version model. Thats quite similar to a normal flying wing in shape. , even have ailerons/ moving surfaces. Wing even jhave dihedral dregree. Vertical fin/fins is the only missing.

By making twist adjustments to the wing instead of adding a vertical tail, its able to create wing vortices inboard of the wing tips as a result of the desired non-elliptical spanload. Commanding a roll would then be creating more lift outboard of the vortices on one wing, a rolling moment that banks the vehicle will be seen along with a yawing moment that yaws the vehicle in the desired direction.
The NASAs Prandtle research is all by models, all gliders, all big wingspan.

I belive by a tailless fightertype jet, electronic stabilization is only way to get it function , at least if wanna hold up to a fighter jet type aircraft. Twistwings been alredy tryed/trying on jets. Twisting wings i suppose are tried in the RC world at replicaas WW1 and earlier aircrafts. Never seen it in function, also never heard how good to handle that was, vs. normal wing.
To make twiststystems on a RC jetmodel outer wing, would in need to make "intricate" systems that also will give extra weight though...

Birds are using eg. the head as one of the corrector on pitch.... thats more similar to canard system.....they can shape wings, and tail (adaptive surfaces) that a aircraft doesnt do... and use their head to adjust position to stabilize their body. Airplanes, on the other hand, have a fixed nose that cannot change shape. the vertical stabilizer will prevent it from shifting off under the force of the wind. .

soo, electronic stabilize controlling is only way on a plane. Does stabilizing systems for RC today be good enugh to control it? even unexpected yaw motions when without the vertical stabilizer? perhaps.

 

[L Edge]

This is what the military are working on, lots of tailless aircraft.

All I am saying is I haven't seen anybody design and fly one. I feel someone can resolve the problems with a gyro and get an Rc model to fly.

 

[FoamyDM]

the prandlt-d was a research design

https://duckduckgo.com/?q=Prandlt-D+wing

Yes... it was a proof of calculation/concept. I have a whole Episode on this, and a build log... as a guy who built it, you can use this for what you are considering. if you don't mind extending the wings about 25% and putting in a 10° twist.

Sorry the first post was only about a flat plate... and this fits the rudderless bill. the Prandlt-M is a better fit for conventional aircraft. just remember only the inner 75% of the wing is lifting.

Here is My Vid proving the flight:
https://forum.flitetest.com/index.p...oard-wing-by-foamydm.58170/page-5#post-662847

I will be putting out a build video and plans soon.

 

[foamboardflyer]

This looks really cool but I don’t see the benefit of a rudderless aircraft. Less drag? Harder to spot on radar? Looks cool?

 

[Flyingshark]

This looks really cool but I don’t see the benefit of a rudderless aircraft. Less drag? Harder to spot on radar? Looks cool?

I think it helps reduce the radar cross section. V-stabs are prone to being at right or near-right angles with the rest of the plane, and right angles are one of the things you want to eliminate first when designing for stealth. And once you've gotten into visual range, the lack of vertical surfaces lets you maneuver more easily on the yaw axis.

 

[foamboardflyer]

I think it helps reduce the radar cross section. V-stabs are prone to being at right or near-right angles with the rest of the plane, and right angles are one of the things you want to eliminate first when designing for stealth. And once you've gotten into visual range, the lack of vertical surfaces lets you maneuver more easily on the yaw axis.

That makes sense. But the lack of a vertical stabilizer also makes it unstable unless you are able to design the aircraft in a fashion similar to the b-2 but it boxes you into a design corner of wing type aircraft.

 

[leaded50]

we can look at airplanes of the 1900-1920... they made it as "a bird" .. big tailsurfaces horizontal, but very small vertical fins.. soo......

But they had enough problem to get enough power to be up in air... controling by sharp turns eg.. wasnt in the iedeas then...

 

[Marzipan]

what we need is antigrav and impulse technology.

 

[jfaleo1]

About as vertical stab free as you get.
https://en.wikipedia.org/wiki/McDonnell_Douglas_X-36

 

[leaded50]

About as vertical stab free as you get.
https://en.wikipedia.org/wiki/McDonnell_Douglas_X-36

"The X-36 was unstable in both pitch and yaw axes, so an advanced digital fly-by-wire control system was used to provide stability. " yep.

 

[leaded50]

A conventional aeroplane is unstable in yaw and needs a tail fin to keep it straight. Movement of the ailerons creates an adverse yaw pulling it out of the turn, which also has to be compensated by the rudder. While a swept wing is stable in straight flight, it still experiences adverse yaw during a turn. One solution is to give the wing sufficient twist for the outer section to angle downwards and give negative lift. This reverses the adverse yaw action of the ailerons, helping the plane into the turn and eliminating the need for a vertical rudder or differential-drag spoilers.
The bell-shaped lift distribution this produces has also been shown to minimise the induced drag for a given weight (compared to the elliptical distribution, which minimises it for a given span)

A strong directional stability is the first way to reduce adverse yaw. This is influenced by the vertical tail moment (area and lever arm about gravity center).
Several technology research and development efforts exist to integrate the functions of aircraft flight control systems such as ailerons, elevators, elevons, flaps, flaperons, and spoilerons into wings to perform the aerodynamic purpose with the goals of reducing mass, cost, drag, inertia (for faster, stronger control response), complexity (mechanically simpler, fewer moving parts or surfaces, less maintenance), and radar cross section for stealth. Expected applications include many unmanned aerial vehicles (UAVs) and 6th generation fighter aircraft. Two promising approaches are: flexible wings, and fluidics

 

[Matthewdupreez]

What happens if you were to use only one airleron control surface for each wing....
Ie . When rolling left only the left airleron moves up this will create more drag on the wing so will slow it down while also rolling.... Just a theory.....

 

[Mid7night]

What happens if you were to use only one airleron control surface for each wing....
Ie . When rolling left only the left airleron moves up this will create more drag on the wing so will slow it down while also rolling.... Just a theory.....

This is essentially how roll-spoilers work. They are on the upper surface and only deflect up - right for right-roll, left for left-roll. They are most commonly used as low-speed control effectors, because of their added drag. High-speed ailerons are favored for high-cruise conditions of airliners where drag is the worst. Note: "High-Speed" does not refer to how fast these ailerons move, it refers to the flight-regime in which they are primarily designed to be used: High speed cruise. They deflect very little, but because of the high speed environment, produce great effectivity. These small deflections and the mechanisms behind them can be optimized such that they produce as little adverse-yaw as possible, but not zero.