Plane Stability issues

[ethasis]

I've finished designing a single-engine plane with working ailerons, elevators, and rudder
http://steamcommunity.com/sharedfiles/filedetails/?id=559567031
However, it immediately goes into a flat spin without any use of the propeller, and when the propeller is used it makes a wider spiral. Without the wings it does not have this problem, but even two aerodynamic propellers on each side of the fuselage cause it to spin, even if perfectly symmetrical.

http://steamcommunity.com/sharedfiles/filedetails/?id=559567334

[FiddleDeDe]

Where is the centre of mass?

[ethasis]

Originally posted by FiddleDeDe:

Where is the centre of mass?

The center of mass is in the middle between the wings. I do notice that one of the wings is shorter, but changing that had no effect. Additionally, I tried using a flying block, which also had no effect. Even having only two aerodynamic propellers where the wings should be causes it to turn. Also, it always turns clockwise.

[ethasis]

On the ground it acts similarly, but it looks like only one of the wings is producing lift, the other is being pushed down. However, both wings are angled upwards.

[FiddleDeDe]

Have you used a rotation mod to alter the angle of the wing blocks? I've seen funny results when they've been rotated, even if they look as if they are mounted symmetrically. I think the physics modelling may not be based on the same angles as the visual model.

If everything is symmetrical, and it still goes into a flat spin power-off, you probably need to move the CoM forward, and/or increase the size of the rudder. As for what happens power-on, I've seen few single-propeller machines on Besiege that have any real directional stability at all - balencing out the torque in a controlled manner is difficult.

[ethasis]

Originally posted by FiddleDeDe:

Have you used a rotation mod to alter the angle of the wing blocks? I've seen funny results when they've been rotated, even if they look as if they are mounted symmetrically. I think the physics modelling may not be based on the same angles as the visual model.

If everything is symmetrical, and it still goes into a flat spin power-off, you probably need to move the CoM forward, and/or increase the size of the rudder. As for what happens power-on, I've seen few single-propeller machines on Besiege that have any real directional stability at all - balencing out the torque in a controlled manner is difficult.

I did use a rotation mod. I'll try to find out a bit more about the physics model. I'll also look into changing the center of mass. However, torque is not an issue as I am using an unpowered wheel connecting the propeller to the fuselage.

[FiddleDeDe]

Originally posted by jsilver919:

Originally posted by FiddleDeDe:

Have you used a rotation mod to alter the angle of the wing blocks? I've seen funny results when they've been rotated, even if they look as if they are mounted symmetrically. I think the physics modelling may not be based on the same angles as the visual model.

If everything is symmetrical, and it still goes into a flat spin power-off, you probably need to move the CoM forward, and/or increase the size of the rudder. As for what happens power-on, I've seen few single-propeller machines on Besiege that have any real directional stability at all - balencing out the torque in a controlled manner is difficult.

I did use a rotation mod. I'll try to find out a bit more about the physics model. I'll also look into changing the center of mass. However, torque is not an issue as I am using an unpowered wheel connecting the propeller to the fuselage.

Even an unpowered wheel will deliver some torque - it isn't friction-free. And I'm not sure that Besiege's physics works quite like the real world when it comes to torque effects - the way people use wheels as 'reaction control' suggests to me that it doesn't.

[ethasis]

Originally posted by FiddleDeDe:

Originally posted by jsilver919:

I did use a rotation mod. I'll try to find out a bit more about the physics model. I'll also look into changing the center of mass. However, torque is not an issue as I am using an unpowered wheel connecting the propeller to the fuselage.

Even an unpowered wheel will deliver some torque - it isn't friction-free. And I'm not sure that Besiege's physics works quite like the real world when it comes to torque effects - the way people use wheels as 'reaction control' suggests to me that it doesn't.

Then that may be a part of it. However, the spinning is still present when flying blocks are used to power the plane. I agree about the torque effects; In planes the solution is to apply trim to ailerons; and even nearly vertical ailerons do little to improve the roll without using unpowered wheels as reaction control. I don't think it would be a good idea to decrease the torque (Or at least not a popular one) as many machines use reaction wheels.

[Akyer :3]

When comes to plane, this is no basic. No matter what how simple it is.

I would not recommended for you to use as an wing as the body. Use brace + Ballast (0.2 mass)

Also, check the elevator or the rudder if they are straight. If not, mod it.


Sometime in Besiege Physic, which in air, when the wheel turn on, it pushes the air like the wheel pushing the water going in circle.