Official FAR Craft Repository

[Wjolcz]

Brake rudders work just like a normal rudder in practice. I messed around with a little craft for a bit, you *need* a little dihedral - my test craft went from terminal sideslipping to fully usable with just a couple of degrees.

https://farm6.staticflickr.com/5782/21633906472_865491df75_c.jpg

Pressure-forward on that and still directionally fairly stable, haven't tried it supersonic yet though.

Edit: seems ok at lower levels supersonic - I'm not sure yaw spoilers are a good idea for a large spaceplane though, you really don't want to be using spoilers for anything on the way up.

Edit2: here's a bigger one. Need fairly large yaw spoilers and also some sort of PID yaw controller.

https://farm1.staticflickr.com/738/21458584218_d38fdbf467_c.jpg

Disabled the cockpit reaction wheel and the engine gimballing, it's pretty stable at low levels - higher levels I need to do some pid tuning to manage.

The big one looks sweet! I made mine a bit more stable by adding more sweep to the outter part of the wing. Still sideslips a bit, but then stabilizes itself just fine.

[Van Disaster]

I added little winglets to mine in the end - I'd imagine any modern non-stealth flying wing ( ok this isn't quite a "flying wing" anymore ) is going to have them anyway. It still has yaw control via spoilers though. I suppose I'd better check it's flight dynamics one day.

I kinda wonder how a forward-swept pure flying wing would work...

Anyway don't get too hung up on wave drag. Looks a bit ugly, right?

30t single engined spaceplane though ( albeit a bit borderline ).

Edited September 25, 2015 by Van Disaster

[FourGreenFields]

I kinda wonder how a forward-swept pure flying wing would work...

Look what you've done! It's all your fault!

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Allthough I'm sure it's possible to make a plane like that fly properly, this one suffers from short development time, and will crash if you roll (-> slip) at low speed.

Anyway don't get too hung up on wave drag. Looks a bit ugly, right?

You think that looks ugly?

My SP 4 Fat Lady II is even worse (wouldn't design like that anymore - both because B9PW and because I now know some more about hypersonic aerodynamics)

Edited September 26, 2015 by FourGreenFields

[Van Disaster]

Certainly interesting looking things - this one seems to have divergence issues unless I strut the outside wings too, that's pretty cool.

And the logical inversion of my previous effort.

Edited September 25, 2015 by Van Disaster

[Littlerift]

Is there any way to make a flying wing more stable without adding additional vertical surfaces to stabilize it? Seems like flying wings like to slip left and right some. I know about making it more dihedral, but maybe some other way to do that as it seems not enough?

Are there any documents regarding the stability issues on flying wings like Horten? It seems like the engine housings on XB-35 were enough to stabilize it and there were vertical surfaces on YB-49 dedicated to do exactly that, but I could not find anything about Horten 229's system of stabilization. Perhaps the side slip (+asymmetrical thrust from the failed engine) killed the test pilot of 229, or were the flaps designed in such way to prevent it at low speeds?

I'm asking about Horten specifically as it seems to have no apparent stabilizers at all. Will experiment with dihedral some more, but would also like to know what you guys think.

EDIT: I also know about B-2's, which uses the engine thrust and nozzles (read somewhere on the forums, not sure where) to direct and cancel out the slip, but I'm using propellers, so that's not possible.

The Ho-229 had drag-rudders on the top and bottom of the wing (towards the tip) that controlled the yaw. However, the plane never flew, so there was no testing regarding their efficacy. It's likely that they wouldn't have given the plane a lot of control: I can remember reading somewhere that experts suggested that the design of the plane meant it would be unlikely to enter a flat spin in level flight or light manoeuvres, but tight manoeuvres might lead to the plane entering a stall, and in such cases the pilot wouldn't have a lot of ability to recover the aircraft. I'll try and find the source for you.

[Van Disaster]

Well, had to at least try - yes the angles for the middle wing panel are all wrong, but that's because there's too much sweep I think and really I couldn't be bothered editing all the wing sections again. Flies horribly! also really needs some long intakes I can't find in this install.

Edited September 26, 2015 by Van Disaster

[herm]

Look what you've done! It's all your fault!

http://imgur.com/a/Fvgdb

Allthough I'm sure it's possible to make a plane like that fly properly, this one suffers from short development time, and will crash if you roll (-> slip) at low speed.

My favorite plane is like this, i downloaded FAR so i can start crafting advanced aircrafts, then i tried, but it doesn't fly so well. I've spended like 5+ hours trying to make it flight well (it does fly, but very bad). Stock + Tweakscale + KAX Jump Jet Engine. Its beautiful, and fly so well in STOCK KSP. Have some pics

Edited September 26, 2015 by herm

[Doke]

@Van Disaster

Wait, does this mean the Klingon Bird of Prey is actually aerodynamically feasible?

@herm

That's a cute plane. I might give it a spin when I've got time.

[Van Disaster]

@Van Disaster

Wait, does this mean the Klingon Bird of Prey is actually aerodynamically feasible?

Last time someone asked "would that *really* fly?" that I ended up building this thing:

but yeah, the Bird of Prey doesn't look too badly balanced, even the anhedral version - good luck persuading that to fly straight though.

[Guest]

Edited October 2, 2015 by RevanCorana

[capi3101]

^^^

That right there is a thing of beauty, IMHO. Going to have to try that tail setup my own self...how does she handle?

[p1t1o]

Last time someone asked "would that *really* fly?" that I ended up building this thing:

https://farm9.staticflickr.com/8592/15744780167_6e6f123060_c.jpg

but yeah, the Bird of Prey doesn't look too badly balanced, even the anhedral version - good luck persuading that to fly straight though.

I know what program you used to watch when you were a kid

[Guest]

^^^

That right there is a thing of beauty, IMHO. Going to have to try that tail setup my own self...how does she handle?

Thanks, so far so good, I'm not even done with wing calibration, drag reduction etc.. and it's already quite amazingly good.

The thing is its wings are suspended each by 1 LV1R meaning that they slightly bend with air pressure, this makes it both more G tolerant and smoother controls.

https://www.youtube.com/watch?v=3tgCjQsOpp8

Edited October 2, 2015 by RevanCorana

[Cinocal]

The right stuff.

[Van Disaster]

I know what program you used to watch when you were a kid

I completely did! and now I use it as reference for models, just like half the people here, heh. But that plane came out of an IRC conversation, nobody ( including me ) thought it would work. It's still a daft idea even if it does get off the ground.

Here's some of my entries for Wanderfound's FAR BDA AI tournament:

All rather WIP, all stock parts aside from the BDA bits, all linked in my sig. All built to be limited to 400m/s too, they quite happily explode above that because I never bothered tuning for it. The stubby one has probably the worst wave drag I've seen...

Edited October 3, 2015 by Van Disaster

[Galacticruler]

So I'm trying to build a SSTD Cargo plane with this, but can't seem to make orbit around Kerbin, or even space most of the time. I'll post photos of the plane in a bit, but for now heres the info:

OPT fuselages, K sized, J Drone Core

large wings, flys moderately good.

6 engines, all of them SCIMITARS(I forgot the mod).

On re-entry from high sub-orbital flight the wings begin to "flap" at insane speeds, the craft then violently explodes and the core moves 2km in 5 seconds before decelerating to 500m/s

EIDT:

Javascript is disabled. View full album

Edited October 9, 2015 by Galacticruler

[capi3101]

So I'm trying to build a SSTD Cargo plane with this, but can't seem to make orbit around Kerbin, or even space most of the time. I'll post photos of the plane in a bit, but for now heres the info: <snip />

For questions like this one, you might try the Official FAR Craft Repository thread; you'll be more likely to receive a (useful) response. That said, lemme look at your imgur album and edit later...

EDIT: Where's your CoM in relationship to the CoL when the tanks are dry? Craft isn't area ruled at all, either; those are some nasty pressure crests right there on the leading edges of the wings and that alone could explain the behavior you're seeing. Forgive me for asking, but do you happen to be a newcomer to FAR? If so, I can give you some more pointers. Probably on the other thread, though.

Edited October 9, 2015 by capi3101

[Galacticruler]

I am infact new to FAR. I do have general concept of how planes work though, and more so how wings, lift, pressure, and speed play into each-other.

As far as my dCoM Idk, how would I visualize that?

[capi3101]

I am infact new to FAR.

I had a sneakin' suspicion that you might be...

As far as my dCoM Idk, how would I visualize that?

A couple of ways - stock, you just drain out all the fuel from your plane in the SPH and see where it goes. If you're okay with mods, install RCS Build Aid; it has a marker that will show you the DCoM.

[Hodo]

I am infact new to FAR. I do have general concept of how planes work though, and more so how wings, lift, pressure, and speed play into each-other.

As far as my dCoM Idk, how would I visualize that?

One of the biggest glaring issues I notice with that craft is its wings.

The wings are straight, this is not a good thing for supersonic flight, which you WILL have to achieve in order to get to orbit. Most of the large SSTO designs have quite a bit of lifting surface to get their bulk off the ground and to keep them from having absurd landing speeds.

Like my current workhorse, which is only a light-medium lifter but I dont need anything larger yet.

It is a bit of a pig when it goes supersonic but it isnt designed to turn well... it is a cargo craft.

[FourGreenFields]

One of the biggest glaring issues I notice with that craft is its wings.

The wings are straight, this is not a good thing for supersonic flight

Pretty much this.

However, it is possible to build an area ruled plane with straight wings. Just alot harder to do, especially when trying to get acceptable wing loading for an SSTO.

[Sauron]

Sooo... does anyone have any suggestions for how to build for reentry? It seems I can make perfectly functional SSTOs but I can't bring them down. General pointers would be helpful.

Also, how to reenter with a plane meant for subsonic surveying flights on laythe?

Also, I'm playing with lifting body aeroshells out of Mk3 hulls but that's not panning out. In that they're violently unstable and don't actually produce any lift. Help here would be appreciated too.

Edited October 10, 2015 by Sauron

[Galacticruler]

Oh...Well, I'll try some longer swept wings next, perhaps with less hungry engines, it enpties it's tanks in the time it takes to launch one rocket without breaking suborbital flight above 50km

Sauron, if I'm not mistaken, coming in at an extremely low angle works better than plunging into the atmosphere like a capsule.

[FourGreenFields]

Sooo... does anyone have any suggestions for how to build for reentry? It seems I can make perfectly functional SSTOs but I can't bring them down. General pointers would be helpful.

Airbrakes behind CoM. Their drag keeps you stable, and makes sure you don't go just as fast.

Also, I'm playing with lifting body aeroshells out of Mk3 hulls but that's not panning out. In that they're violently unstable and don't actually produce any lift. Help here would be appreciated too.

Lifting body only really works at high speeds. May want to reenter, and steer a bit using lifting body, but then land using chutes.

Also, you'll still need stabilizers. And keep your CoM as close to the nose as possible.

That said, my experience with lifting bodies is based on reentering with former rockets. Never actually built a lifting body.

[Shazbot]

Does anyone know the mach 1 wave-drag area of some real jets? I want something to compare my designs to.

Also, some silly maneuvers:

http://webm.host/33e45/

http://webm.host/51e40/