Rockets are easy. Planes on the other hand...

[Pipcard]

For me, the hardest thing in KSP is making a plane that fly. The hardest part of that is landing on a runway. I believe the reason is that the controls aren't even smooth. Even when fine controls are turned on (caps lock), the plane keeps rocking up and down when turning or exiting out of a turn. Trying to land on a runway either causes the plane to bounce off or to crash.

And for most of the time...

The plane keeps swerving/veering left or right on the runway when trying to take off.

I put the center of lift behind the center of mass. I even put the wheels perpendicular to the ground. It still happens.

[Cranium]

Sometimes I see fellow Kerbonauts try to overengineer their spaceplanes. You don't really need tons of control surfaces to make a flight-worthy plane. In general, you need a minimum of one control surface for each side for yaw, pitch, and roll. So you at least need elevators/aelerons, and some sort of tail fin. Often, I see people put canards, aelerons, elevators, and tail fins, with winglets on their planes, and then they wonder why it twitches out so much while flying. Less is sometimes more in planes.

[Pipcard]

I don't even put lots of control surfaces on my plane.

[Whatshtisthis]

Use SAS, it helps a lot.

You have to watch your speed while landing though.

[fatfluffycat]

I played for over 350+ hours, and I have not made a single spaceplane or ssto that works

Landing on the runway is easy for me though, I landed Bobcat Buran many times on the runway.

[amo28]

I notice the flapping when using B9 control surfaces. They're just too big. Try using the control surfaces from Taverio's Pizza & Aerospace. They're much more realistic and I don't find my planes flapping anymore. However, they don't have as much lift as some of the B9 surfaces do, so you're going to need to work your CoL around that.

[TicTacToe!]

Plane-building is an intense school of engineering for me. I remember back in the heyday of my space program when I detached the command pod with a chute in order to "land" my kerbal. You see, I'm a purist, so I don't believe in landing gear Ahh but with modern times, you have to adapt, so they're there now in the oft chance that I do actually land at landing speed.

[zzz]

Everything is fly in KSP. Put some wings. no matter how, just look at CoL, put some engine at back and sprinkle it with intakes and it will fly. Well, it's little more complicated then rockets, not just twr, but when you learn some simple rules it will be same easy.

Landing at runaway can be tricky but aircraft didn't matter much it's just about right direction(need runaway analog of "docking helper indicator" mod or how it's callrd). And why someone need to land exacly at runaway?

With FAR planes more intresting.

Edited October 3, 2013 by zzz

[Rage097]

I've had this issue. My explaination?

Edited October 3, 2013 by Rage097
Becuase big picture is big.

[Hodo]

I can say that FAR is the best thing to the KSP aerodynamic code since... well ever. I can't build a plane now without FAR. Now I can only build SSTO planes and struggle with heavy lift rockets.

[Kronikor]

The secret to making a stable SSTO spaceplane is to turn on the indicators for center of mass and center of lift while constructing. When you are finished, you should have a plane with a center of lift that is inside the center of mass, but just behind it. If that's not clear:

The mid point of your center of lift, should be nearly touching the midpoint of your center of mass, but still just behind it. This will create a stable, easy to fly plane every time if you positioned your control surfaces correctly. But even if you haven't, it will still fly perfectly when you're not touching the controls. Keep in mind though, that while you fly you burn fuel, and this will alter your center of mass - so your plane may be a completely different bird that it started once you burn down most of your fuel - take that into account when making your reentry. Typically though the front end will want to be a bit squirrely - your plane can be made more manageable by installing RCS thrusters, necessary thought if you want an SSTO.

[Kronikor]

I played for over 350+ hours, and I have not made a single spaceplane or ssto that works

Landing on the runway is easy for me though, I landed Bobcat Buran many times on the runway.

Nice! BUT WHAT?! Intakes INTAKES INTAKES! MORE MORE MORE sometimes I use as much as 15 radials and 2 rams, ideally you want a plane that can travel at around 1300m/s @ 23.5km and then activate your rocket engine(s). Using action groups to simultaneously close ALL intakes and shutdown the jet engines while activating your rocket engine will simplify this task exponentially. I only use 1 and 2 to fly, 1 activates my jet engines, and once I'm at the appropriate speed I use 2 to toggle from jets to rocket and close intakes. Pitch way up and off you go!

[Dispatcher]

I've spent most of my time with "planes" instead of "rockets" in KSP. The above is generally good advice. I've not used mods (other than my own parts) yet simply because I like to see how things work in the game as it is. There are two views on planes (which can be aircraft and/or spacecraft; typically made in the SPH and launched on the runway or from orbit). I've seen some posts by knowledgeable forum members actually recommending that the CoL be slightly ahead of the CoM. However, most posters and tutorials suggest that the CoM be slightly ahead of the CoL. In either case, they should be ahead of the CoT. I have actually done both with the CoM/ CoL arrangement. It all depends on your objectives. For general use, CoM ahead seems best. For some lower throttled planes which glide after running out of fuel, I've had success with the other arrangement. I've also had success with angled landing gear under the rear of the fuselage, for lower throttled planes. Full throttled or more powerful planes seem to do better with perpendicular gear at the rear. Some people prefer the rear gear as close to the CoM as possible; others like that gear closer to the rear so that its harder to knock the engine off during take off. Experimentation usually yields something in between for me. So try to have fun as you try things out. You never know when you'll find yourself with an exceptional plane. :-)

[SRV Ron]

One really needs a flight control, 3 axis, joystick for flying. Until the physics gets updated for all parts, building aircraft that fly realistically will remain a challenge.

[Brofessional]

This mod helps a lot, on top of being handy for placing your RCS thrusters, it lets you see the center of mass when your fuel is empty.

[Hovis]

Works out like this, space planes are harder to build, engineer and fly than rockets. However they are in some ways better. Why are they better? Well because they are vastly more efficient in terms of fuel, and the fact that you are not dumping off great big valuable chunks of space rocket on your way up into orbit. But of course because nothing costs anything in KSP this advantage is lost. So in effect they are much harder to use with little real in game benefit.

I could be wrong, but my take on it is that the SSTO space plane, capable of flying between planets, even landing on them or on moons, and coming home, is pretty much the greatest design challenge in the game. It may not even be possible.

I'm not great at the game, not even close to great, but I've seen some amazing things built on here, and on vids and so on, and the most impressive things almost without exception are the space planes. That stuff is hard. Harder than rocket science hard.

There's nothing wrong with it being hard to do, it just is what it is.

[khyron42]

Plane making definitely is a bit different than rockets. However, the particular problem you're asking about has happened to me a few times and I could probably give advice for design changes... if you can post a pic or two of your plane in the SPH, with CoL and CoM shown.

Usually it's due to your rear landing gears being too far back on the plane; attempting to take off puts a LOT of downwards force on them if they're installed that way, and they bend themselves slightly, leading to the left or right veering. Getting them just slightly behind your CoM is the best design, but you can also add struts.

Edited October 4, 2013 by khyron42

[Starglider]

I've noticed when keyboarding that when I yaw left/right, ASAS sets the pitch and roll controls to center (even if the controls are trimmed) which cause further issues. So now I use a hotas (hands-on throttle and stick) controller, so I can control all three inputs at once (and get better throttle control too), and rely on ASAS only when I want to fly straight. The difference is like waking up from a nightmare. As for "drift", you can use trimming to fix that once your off the keyboard.

My recommendation is to get an actual flight controller, build a small, normal airplane, and practice "touch-and-go" runs (by that, I mean land on the runway and immediately take off again). Once you've mastered landing, piloting in general is a breeze.

[Pipcard]

I'm currently experimenting with making spaceplanes. The problem I'm currently having is not having enough pitch control (as well as rocking in various directions when trying to do that). My plane barely pitches when taking off and doing banking turns.

And I actually made it into orbit once with an SSTO spaceplane today. Getting back down is the real challenge.

edit: This is the plane (slightly modified from the one that I took into orbit)

Edited October 4, 2013 by Pipcard

[SkyHook]

Install FAR and get back to me lol

[willy123]

I started playing the game with planes. I got an ssto with only ion drives, solar panels, and jet engines into orbit before I learned how to land on the mun (or and other celestial body). That said, planes are like a different game. Practice with the stock builds. The advice given is pretty good, though for a high velocity planes, ram air intake is best. I don't even use radial. Keep your center of mass and lift close. Keep in mind the shift of center of mass as fuel is consumed. Planes rolling left and right on the tarmac is a great annoyance, yes. Make the front wheel as far forward as possible, and push the back wheels as far apart as possible on the hull, keeping the perpendicular. The best approach, though, is just getting that damn thing into the air as quickly as possible. If it doesn't lift off quickly, add more lift, like wings. Make sure the front of the plane is tilted slightly up in the front and there is a source of lift in the front.

As far as landing them... that's tough. I usually just add parachutes and float in lol.

[Pipcard]

I want to do it without installing a mod that changes the aerodynamics of everything.

[willy123]

Too short. Make the plane longer and add small wings near the front. Replace the jet fuel with an empty jet fuel tank, and move the jet fuel tank to the middle, add small wings to the front (cockpit area), fly! fly! fly!

[Brofessional]

I'm currently experimenting with making spaceplanes. The problem I'm currently having is not having enough pitch control (as well as rocking in various directions when trying to do that). My plane barely pitches when taking off and doing banking turns.

And I actually made it into orbit once with an SSTO spaceplane today. Getting back down is the real challenge.

edit: This is the plane (slightly modified from the one that I took into orbit)

http://imageshack.us/a/img13/7418/mzio.png

http://imageshack.us/a/img802/4923/br68.png

The trick is to keep your wet CoM and dry CoM nearly identical so your CoM doesn't shift as you empty the fuel tanks. If you're using tail mounted engines this means the front of your plane needs some weight to it, as the engines are usually the heaviest part aside from the fuel tanks.

CoL should be just a hair behind the CoM, with your main wings next to the CoM and a second pair of wings either in front or behind the CoM to stabilize it, depending on your design. With only a single pair of wings you're likely to end up flipping end over end.

You don't necessarily need a lot of control surfaces for SSTO's as they mostly just fly in a straight line. If it's a light plane, a single pair of flaps on your main wings will usually do. The fewer control surfaces you have the less twitchy it will be.

If you're having trouble getting into the air, try positioning your landing gear to the tail sits lower than the nose on the runway.

I'd recommend getting the Editor Extensions mod and using clusters of the 48-7S engines instead of aerospikes, much better TWR. Also those cylindrical jet fuel tanks usually have more fuel than you need for a single engine SSTO. I recommend using a smaller tank or cruising to burn off excess fuel before switching to rockets, so the rockets have less weight to push.

Edited October 4, 2013 by Brofessional

[Pipcard]

By switching from the aerospikes to the LV-909s (since the aerospikes were only used once they were in the upper atmosphere), I had less mass and more delta-v.

But I still have pitching problems. And it seems that most of them occur at takeoff with the landing gear deployed.

Edited October 4, 2013 by Pipcard