Turn a plane

[Carl]

Okay, having very few issues building a plane that will lift, a fair few need a rather longer runways ideially, but they will work as far as going up and down are concerned. But try to turn and one of two things happen:

1. The plane turns very slowly, rolling a bit as it does. Fine as far as it goes but very hard to get it lined up on anything and typicilly it refuses to climb whilst turning.

2. It does a complete and rapid 360 degree roll at the slightest turn attempt and goes wildly out of control.

I can't seem to build a plane that got any ability to manuver to speak of whilst not being uncontrolably unstable. Of course 75% of the problem is my inability to use my joystick, with the fairly imprecise keyboard inputs you have to build a perfectly stable plane to have any hope of controling it.

[AncientAstronaut]

Unfortunately this happens to me, too. My hypothesis is that KSP simply isn't ready for planes... They added them too early. A lot of the physics need to be fixed, they use the same physics as rockets, which is bad, and I have yet to actually see or build a spaceplane that can be turned without a joy stick.

[sal_vager]

Carl, pics and a craft file would help immensely with working out your problem, the turning though, are you just Yawing (A,D) or are you Rolling (Q,E)?

[Ydoow]

Planes are really tough right now, certainly not impossible, but tough for those with a real basic understanding (me).

Next version will IMMENSELY help with spaceplanes and the like with the addition of a Center of Gravity marker. This affects pretty much everything to do with a plane, especially turning and lift.

[Carl]

@Sal: I'll throw a few together. Right now i only save stuff that works, nedless to say with my sucsess rate that means few saved craft.

@Everyone else: Well at least it isn't me . I'd gathered the physichs was probably to blame.

Hope we get a centre of lift marker and some symetry updates, and snap to on strut endpoints eventually too .

[jfx]

If you get the balance approximately right and stick enough control surfaces at the problem it will handle fine (though still with weird keyboard controls )

I stripped all modparts away, should run on stock KSP, no Mechjeb. I made this plane to test the tricouplers as angine mounts.

example plane - still needs a bit of trim and in my test flight i forgot to strut up the external tanks but it flew nicely until Shercroft had the dumb idea to impress the girl working in the VAB with his flying skills.

https://www.dropbox.com/s/noj5f0f7pllevnr/Kerbostar.craft

example flight (might take a while for youtube to process):

Edited August 16, 2012 by jfx

[Carl]

2 craft. The first is an example of the slow dosen't want to turn veriaty, The second the wildly uncontrolable type.

Both use mechjeb, (i thought the auto SAS might make them control better, sort of works for the first, not at all for the second).

TBH another god change would be seperate aierilon and elevator surfaces as the current system is very non-ideal.

[Chickenkeeper]

Use the 'Alt' key and thr WASDQE keys to trim the aircraft to stop the slow rotation, but as for the over-sensitivity I can only suggest making a bigger plane, or angle the wings up slightly

[Hyratel]

I've had varied success with spaceplanes, however I enjoy using a gamepad. makes it so much better.

requires Aero Engines pack - http://kerbalspaceprogram.com/forum/showthread.php/15348-0-16-Spaceplane-parts-rescales-edits-and-additions

MAKE SURE to close the plane's landing gear before takeoff or you'll get massive instability. this is an experimental rocket boosted takeoff vehicle. you'll want to turn off the RAMjet engines so they don't waste fuel, if you're sticking to low altitudes. flight ceiling 18,000meters or so, that's with MAXIMUM elevator because of the huge angle of attack needed at that altitude with the amount of wing it's got.

[Zephram Kerman]

Just in case you don't already know, planes don't turn like rockets. The lift of the wings supplies the force to turn your direction of travel. So first bank, then pull up. ("Bank & yank" as they say.)

Otherwise, perhaps try a totally different configuration. Because of the way various things work, I've been having good results with delta-style planes, like the Concorde. Also, using alt-ASDWQE to angle the wings and controls really helps with trim convenience and getting off the runway.

[pebble_garden]

Because all the advice is scattered across multiple posts, I'll consolidate the essentials into one post. And add a couple more points.

Q and E keys to bank: As Sal_Vager said, use these to roll the plane, not A and D. Once you're banked, use W to pull your nose into the turn as Zephram Kerman pointed out.

Too-sensitive controls: Try pressing Caps Lock to make your keyboard inputs finer. It toggles between coarse and fine input amounts.

Trim: As Chickenkeeper said, you can use the alt+WASDQE to trim the control surfaces, but I recommend only using this for the W and S keys. If you need more than a keypress or two, though, your plane should be altered for balance (see below).

Good balance: In planes, as with rockets, proper balance is everything. The next version will have a visual indication of center of gravity while building. But in the meantime, all I can say is test-adjust-test-adjust until you are satisfied. If the plane has a tendency to pitch up, try moving some weight forward, or the wings back a bit. Moving canards forward or back a little can help. If your engines are thrusting above or below your center of mass, that'll make your plane tend to pitch as well.

You can also try changing the wing angle (with Shift+A/D for angle of incidence, and Shift+Q/E for dihedral).

http://en.wikipedia.org/wiki/Angle_of_incidence

http://en.wikipedia.org/wiki/Dihedral_%28aircraft%29

Example plane: Here's a simple plane I designed with minimal parts, balanced to fly nicely with keyboard input. It helps to use Caps Lock, though, for finer control. Feel free to tear the plane apart to see what I did.

http://kerbalspaceprogram.com/forum/showthread.php/15785-DiamondWing-jet-trainer-%280-16-stock-parts%29?p=223900&viewfull=1#post223900

Edited August 18, 2012 by pebble_garden

[Carl]

Trim and Caps lock are more or less ok, (in that i can trim it for straight level flight), though since you said that i do tend to have to trim my planes with a fairly strong upwards cant on the control surfaces.

The real issue is that none of my planes will even stay in the air without wings level and are pretty reluctent to roll or climb in the first place. I suspect insufficent wing area t weight is the issue.

@Pebble_garden: Nice example aircraft fairly easy to fly if a touch over-sensetive even with caps lock. I notice in that thread you mention using a joystick, I though KSP didn't support them? I don't remeber any patchnotes about them, but i haven't been around here reguarlly for a few interations. Anything special i need to do to get my joystick working?

Balance is probably part of my issues TBH, though that dosen't fully explain why mine are such mollasses on both controls and climbing it would probably explain a few other things.

[pebble_garden]

Nice example aircraft fairly easy to fly if a touch over-sensetive even with caps lock.

Yes. I think for a first pass the space/plane implementation in KSP is pretty great, but I'm hoping there are improvements like fly-by-wire component or keypress smoothing. I suppose a bigger plane would be a little less twitchy, because of the added mass. You can always turn on the SAS built into the crew pod, that acts as a kind of keep-this-attitude autopilot.

I though KSP didn't support them? I don't remeber any patchnotes about them, but i haven't been around here reguarlly for a few interations. Anything special i need to do to get my joystick working?

Yeah, just go into Settings > Input and look on the right side. Click on the axis you want to assign, then wiggle the control on that axis. I was able to do it with both a wired Xbox360 control and a joystick. There's a thread or two on this forum about suggested settings.

Balance is probably part of my issues TBH, though that dosen't fully explain why mine are such mollasses on both controls and climbing it would probably explain a few other things.

Shoot me a .craft file link and I'll test it out.

Edited August 18, 2012 by pebble_garden

[Carl]

Ahh cheers on the joystick, that should make it so much easier

As for a craft. See the link, modified a prior design to all stock parts for you, (i tend to add mechjeb to most things ).

[Rickenbacker]

You get some wierd wobbliness sometimes, since KSP isn't very good at deciding what control surfaces to use for what input (it always wants to use as many as possible, which often means that when you roll, you also get full rudder, and things to go hell in a handbasket). But like the poster above said, you simply don't turn an airplane with rudder, roll in the direction you want to turn (maybe with some rudder input to keep the nose pointing the way you're going, then pull up to turn.

[colmo]

I like to think my planes are pretty polished now, so give them a go. I spend most of the time making sure they don't need in-flight trim, at least around take-off.

You'll notice that the distribution of mass and control surfaces make big differences to the way a plane handles. Deltawings work so well because the mass is centralised, making them very manoeuvrable, whereas if you start to space the engines out on the wings, you'll notice the response is slower and 'safer'.

If you want a really safe plane, use dihedral wings (they sweep up) which will self-right the plane. Canards too close to the nose will cause those fatal nose-up flips, shift them back a touch. If the standard canard gives too much lift, switch to the winglet, and vice-versa (handy for balancing the lift of tail-fins). Adding 5 or 10 degrees angle of attack to wings and canards increases their lift, good for planes designed for high speeds. Slower planes are best relying on innate wing lift.