Air intakes pulling the plane sideways ???

[128MB]

I have never been able to get a plane out of the atmosphere.

Tried very simple and very complicated designs, but when supersonic any plane will start to go left or right, no matter how many air intakes i place, and yes i always use symmetry!

I tried a mad design today with 26 intakes the thing could sped up within a minute to 1600m/s but then it started to spin to the right and i could not get out of the spin unless i closed the intakes.

[KerbMav]

They very well can if they are misaligned, as they create drag (on their position).

You may want to attach your intakes to something else so the editor does not place them at an odd angle like in your picture.

[DrMonte]

Usually an engine makes airplane to spin, not an air intake. One of engines leaks resources earlier than the other and it's off and you are in trouble.

[nhnifong]

I think it may be that your intakes are pointed at an angle. Intake drag is proportional to the component of the intake's open face direction that is aligned with the direction of motion. The way you have assembled it produced a positive feedback loop in the yaw. When you yaw left, the intakes on the left are pointed more into the airstream, and create more drag on the left, pulling the plane even further to the left. In other words, you created an unstable system that is sensitive to initial conditions.

Try swapping the intake angles, such that intakes point inward slightly instead of outward. This should create a negative feedback look in the yaw and actually stabilize the plane.

Also, You probably used an action group for the intake close function. Keep in mind that if you grab and replace a symmetrically placed part which already has an assigned action group, that action group will be removed from any symmetric copies of that part. This is a bug. If you closed some intakes before taking off, it is possible that only the intakes on one side of the plane are closed.

[128MB]

No no its in every plane, only this one is angled!

This plane flies perfect untill going over supersonic.

Even if i make the most basic ssto and not even touch the yaw controls, the plane always spins out of control after going supersonic.

Edited November 11, 2013 by 128MB

[Kasuha]

My ideas:

You seem to use modded parts. Are you having the same problems with stock only?

While getting up to speed your place loses fuel and loses mass at the place where the fuel tank is. That might move the center of mass behind center of lift, making the plane unstable.

To reach high speeds you usually need to get high and there's very little air there. If your intake air gets too low and you have two engines on sides, only one will usually flameout, getting your plane to a spin. Centrered engines usually help.

[arq]

You could add a tail plane behind the craft. Some stabilizers further back from the CoM would help to keep it flying forward. Your near-complete lack of vertical stabilizers is doing you no favors on this plane.

[Traches]

Few things you can try -

Move your center of lift further back. This makes you more stable.

Move your center of mass further forward-- same as above. Picture an arrow shot from a bow.

Add a bigger vertical stabilizer (I can't see one at all!)

As far as your intakes - ramjets are the only ones worth using, don't mess with the others. Mount them further back; if they're mounted forward they'll pull your nose around. Also, quit airhogging so bad!

[UmbralRaptor]

Intakes are very high drag, especially at speed. If they're generally in front of a craft's center of mass, they'll make it unstable. Try placing them farther back?

[Luxmaster-CZ]

Dude, learn to use imgur... I will not look at your craft, as picture would take like 5 minutes to load..

And no, its not my connection..

[numerobis]

Picture works for me.

I'm going to bet that the issue is that your jets out back are flaming out at slightly different times when you run out of air. More intakes will only delay the time that this happens.

[How2FoldSoup]

You could add a tail plane behind the craft. Some stabilizers further back from the CoM would help to keep it flying forward. Your near-complete lack of vertical stabilizers is doing you no favors on this plane.

This would be my guess. You probably get knocked a little out of alignment on yaw and then due to how drag works with the intakes continues to throw you off. Adding more yaw stability would help you a lot here.