Odd question on twin rudder planes

[Hoomi]

After flying the Cobble a few times, I started wondering something -

Ground vehicles with two front wheels for steering, gain a bit of stability from a slight amount of toe-in on the wheel alignment. Toe-in refers to having the front of the wheels slightly closer together than the back of the wheels. Without this, the car tends to not track as well while driving straight.

Is there a similar effect on twin rudders? Does a plane's stability in straight flight benefit from a slight bit of "tail-in" (for lack of knowing a better term) in the adjustment of the rudders, so that they are not exactly parallel?

Just seeing if anyone with more experience in plane design (which doesn't take much in my case) can satisfy my curiosity in this regard.

 

[GliderFlyer]

After flying the Cobble a few times, I started wondering something -

Ground vehicles with two front wheels for steering, gain a bit of stability from a slight amount of toe-in on the wheel alignment. Toe-in refers to having the front of the wheels slightly closer together than the back of the wheels. Without this, the car tends to not track as well while driving straight.

Is there a similar effect on twin rudders? Does a plane's stability in straight flight benefit from a slight bit of "tail-in" (for lack of knowing a better term) in the adjustment of the rudders, so that they are not exactly parallel?

Just seeing if anyone with more experience in plane design (which doesn't take much in my case) can satisfy my curiosity in this regard.

I think yes, since that would cause more drag in the rear, which would keep the tail back more like fins on a dart or rocket.

 

[Hai-Lee]

My experience is actually NO. The vertical fins will try to balance the drag and point the plane accordingly and so toe in or toe out will just add drag and not provide any real benefit.

Just the height and surface area of the fins will add drag and this drag will want to equalise, (a bit like a drag chute), and of course drag the plane to point accordingly.

So apart from an increase in drag it will make little difference on a model but on a full sized bird the fins acting in opposition can increase the structural load on the fin attachments and even cause their premature failure.

Just my thoughts though, so give it a try!

Have fun!

 

[Merv]

.... Does a plane's stability in straight flight benefit from a slight bit of "tail-in" .....

I always add a bit of toe in to the winglets of my Versa, about 1/8 of an inch. This completely eliminates the wing waggle.