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Jet plane keeps veering to left or right. Don't know why.


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I have built my plane as symmetrical as I can build it. Each time it goes on run way, after changing landing gears, deleting wings in case too many, been unable to find out what is causing it.

Has anyone else experienced there jetplane veering of to the left or right then tipping its wings and exploding? At one time I had the plane stable by adding lots of landing gears, but it just spun around in a circle at 20m/s.

I have built successful craft that fly into the sky, but I copied my landing gear and wings originally from that craft. It never veered off.

If this has happened to you, did you managed to solve the problem or figure out what was causing it? I went from a jet plane with really good lift and I thought was going to be my first plane into orbit too a plane that can't go 20m/s without spinning on the ground. Really no idea how that happened.

Edited by Moonfrog
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Also, make sure your front gear clearence is higher than your rear one. If it's the other way around, your starting AOA is negative and wings act like spoilers, pressing you down to the runway. At a high enough speed, it will cause your plane to tip and fall over.

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This. Angled landing gear is deadly for some reason.

Simple answer to this is.....

Wheel Alignment.

If you have to much camber on a wheel you actually change the alignment and contact patch with the ground. This can cause a vehicle to drift one way or another, or just cause higher than normal tire wear. In racing you may want more camber to help offset some of the lateral forces the car goes under when cornering or due to track and weather conditions.

But also the toe of the wheel comes into affect, this is something a lot of people don't take into account. Toe also has affect on how a vehicle will handle, and will have a great deal of affect at higher speeds.

Last but not least is caster, in racing the joke is, "Caster is that thing that keeps the driver happy." Truth is caster affects several things, both your feel through the steering wheel of a real car, but also the amount of input required to get the wheels to turn when moving. To much caster and the wheels will basically be a pain to turn and will feel like driving a sled. To little and it will feel like you are driving a unicycle and feel like the car is twitch and overreacts to bumps in the road.

Sorry to go off on a tangent but I am a former automotive technician for Volvo and Nissan, and a avid Nissan Z car fan I own one that I used to race. So car setups is kind of my "geek" thing.

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I've had this many time and it took me a while to figure out the problem.

Angled landing gears play a part so if you have them - reconsider their placement.

When multiple wheels touch the ground slight variations in roll can make some wheels touch the ground while others are up in the air. It will be such a small variation you can't even see it. The effect is that the wheel touching the ground causes drag, pulling you to one side until the plane corrects itself and the opposite wheel touches the ground, pulling you the other way. The oscillation will eventually make you crash.

You can fix this by reducing the number of wheels (3 is sometimes better than 4) or by bringing them closer to the fuselage instead of out on the wing, where the effect will be much more pronounced.

Many Kerbals have died needlessly for that one.

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[snip]

Sorry to go off on a tangent but I am a former automotive technician for Volvo and Nissan, and a avid Nissan Z car fan I own one that I used to race. So car setups is kind of my "geek" thing.

What kind of Z? I had a 1990 TT 300zx and it was by far, the most fun to drive vehicle that I've ever driven. It was unfortunately crushed under the trailer of a semi-truck when he swerved into my lane to avoid a stopped car up ahead -_-

On topic though, this seems to have happened to everyone at some point. If changing your gear placement doesn't work, try throttling up slower instead of full power from the start. Pitching the plane up constantly can help as well.

If you have any serious interest in building and flying planes, look into getting FAR. Aerodynamics actually apply with it, and it smooths your controls out if you're using a keyboard.

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  • 6 years later...

Another cause of your plane veering to left or right is improper engine, wheel and wing design. If you made a taildragger and the tailwheel is rotated at left or right or is facing sideways, either left or right, your plane will veer to left or right. If there is only one engine on left or right wings, your plane will also veer to left or right. If your wing is improperly designed, (e.g other wing on the other side having a span smaller than the other wing's wingspan or having only one wing on any side), the plane will turn to left or right, making it uncontrollable and crash upon takeoff.

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Nobody seems to have mentioned reducing the front wheel friction yet, so I will.

With advanced tweakables on, reduce the friction on the front wheel so that it's about 0.5, this can greatly improve plane behaviour on the runway as often the front wheel will produce too much friction and can make the plane start to pivot around it due to the thrust being at the back. You should also never use the wheel steering when trying to take off unless you're going slowly (<15m/s or so) or the plane will become very unstable and could clip a wingtip on the ground or tip over entirely.

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2 hours ago, Spricigo said:

Was it an option back in 2013? :rolleyes:

Blech, a 7 year old necro and I didn't even notice... If it wasn't for that thread from 2012 that someone resurrected last month, this would probably be my all time record.

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