Noob question: Spaceplanes

[Deaghaidh]

Sorry if there is already a thread about this, but is there a guide somewhere on how to build and operate the planes? Mine just dont work, the engines dont even start. Often uneven landing gear causes them to just fall over and explode on the runway. Its quite embarrassing.

[Vanamonde]

It would help if we could see a screenshot of your plane.

If the landing gear is uneven, are you not placing the items with the "symmetry" tool? That's one of the round gray/yellow buttons on the upper left of the assembly screen. Whatever you place on one side should be mirrored on the other if that is turned on. Or if your planes are falling over while rolling, everybody's planes do that. It's a bug that they know about and are working on. For right now, place the wheels as widely apart as possible, and it will still veer to the side, but hopefully keep going long enough to takeoff.

If the engines just don't start at all, mostly likely fuel is not getting to them from the tanks. Some parts transmit fuel to the tanks and some do not. The ones that do say "fuel crossfeed" on them. Put crossfeed parts between the tanks and engines, or you can use the little fuel conduit thingy to link a tank to an engine, but placing the conduits can be a little tricky sometimes because they don't always stick right where you want them to. Oh, or you might not be turning the engines on. You have to tap the spacebar once to turn them on at the start of the flight, and then they respond to the throttle.

Edited August 11, 2012 by Vanamonde

[air805ronin]

I just discovered the game two nights ago. I did rocketry the first couple nights. I just tried my first space plane tonight. After 4 crashes on the runway I learned 2 things. Don't have SAS on when you take off. Don't make your plane too heavy versus the amount of thrust you have. Actually I learned 3 things. Flaps on your main wings can be a very good idea...thought they're called something else in the part menu.

With all that said, drag and symmetry can be a huge deal on a space plane. This was my third revision that I managed to get into orbit. Landing...well....not so much.

Good luck! Once I'm not a new member, I'll post a craft file for you so you can see the design I'm running with.

[vexx32]

They're control surfaces, not flaps

Flaps are designed to slow the craft and nothing more. Control surfaces are used to allow you to actually fly where you want to go.

At this point in time, KSP does not have flaps.

[Zephram Kerman]

You got a space plane into orbit after only three revisions? That's very impressive!

Here are some ideas, which I plan to develop more fully:

• remember the KSP drag model is weird (a full fuel tank has more drag than an empty one);

• the lift model is weird too (lift is generated by the angle-of-attack, not Bernouli's principle);

• center of mass should slightly forward from center of lift;

• for tricycles, main landing gear should be just behind center of mass

• (for tail-draggers, main landing gear should be just forward of center of mass);

• do not use rudders to turn... instead, first bank, then pitch up towards your desired heading ("bank and yank");

• put fuel tanks near the center of mass, so that they do not affect trim as they empty out;

• canards give lots of control authority, but cause a tumble if Angle-Of-Attack is too large;

• put elevators aft... if they're near the middle they don't help;

• remove rudder / aileron control surfaces, only use elevators (because of the way control surface movements are mapped like RCS thrusters);

• it takes at least 2 Gs of lift to "un-stick" from the runway. (I'm unsure if this is correct; can anyone verify?)

Troubleshooting:

• if it roars down the runway into the water, add more lift or remove weight;

• if it veers off the runway just before rotation, pull back on the stick (to reduce nosewheel pressure);

• if it stalls and tumbles, move the wings back;

HarvesteR, the big Kerbal himself, posted some tips and photos here: (The rest of that thread is helpful, too.)

I hope these tips help!

[Binky]

I've given up on spaceplanes for a while. After many attempts, I started to name them things like "Burning Wreck 1b" and "Smoldering Debris Mk2" which should indicate my success rate

Jeb still wants to fly them though...

[Rickenbacker]

Actually, flaps increase both drag and lift. Very useful for landing. Airbrakes are designed to only slow the aircraft, but we don't have either in the game right now.

[vexx32]

Right. Serves me right for zoning out in Aero class xD

Yes, that's why they're always used for landing and just about only that... they can result in the craft being damaged if used at high velocities.

[air805ronin]

I've given up on spaceplanes for a while. After many attempts, I started to name them things like "Burning Wreck 1b" and "Smoldering Debris Mk2" which should indicate my success rate

Jeb still wants to fly them though...

I may have had only 3 revisions, but I did have about 30 crashes due to not knowing how to fly them. (SAS account for nearly 10 of those before I figured out to turn it off). I moved back to my rockets because I'm trying very hard to actually land on Mun.

Regarding my "flaps" gaffe...my bad. They are control surfaces. I just couldn't remember that term last night. Plus, I don't have formal schooling in any of this so I don't fully understand the difference until its explained to me.

[vexx32]

Nah, it's OK. I just thought it's better to point out the difference as best I could. Even I overlooked a few things with em, but ah well.