V tail set up

[Paul Williams]

Hi all I am converting an old glider to a V tail I was wondering what the recommended angle would be and if the tail sections should be in line with the fuse. I am guessing a more acute angle would give more rudder control and visa versa. So should I build the tail to 45 degrees would that give even control for rudder and elevator?

[simon burch]

I remember designing a v-tail glider when I flew as a kid at Bradgate Park in Leicester. At 90 degree's the tail response was quite aggressive and I was advised not to go less than 90 degrees (obviously I tried it, but the tail was uncontrollable). I would aim more for 100 degrees, but I'm sure there is a set of design parameters somewhere which will give you an optimal angle.

When you say inline with the fuse, are you talking about the angle relative to the wing? If so, I would keep it the same as the original horizontal tailplane.

Remember when you set up the mix for the rudder, it sort of works in reverse. From behind, left rudder will make the left elevator go down (not like with ailerons).

Simon

[PatMc]

I'm pretty sure that the recommended included angle is 110 deg. Logic says that it should be lined up to give the same incidence as the tailplane it's replacing.
I've only experience of a couple of V tail models, last one was a 98" Salto, the elevator control was normal but rudder not so powerfull as with a seperate vertical surface.

[FWAL]

110 degrees

What glider are you converting and are you a 'stab' at the relevant sizes

[Gixerbenten]

110 on mine

[Simon Chaddock]

If you have the existing fin/tail plane dimensions a good starting pint is to make the V tail with the same projected plan and elevation.

Even then the rudder function will not be the same as a vertical fin as there will be a stronger torque effect tending to lift the inner wing resulting in a weaker flatter rudder only turn.

If you fly "bank and yank" (no rudder) then the weak rudder response is not a problem!

110 degree V. The single 'elevator' servo is mounted in the root of the left hand tail plane but works both surfaces. It drops a wing readily at the stall and falls into a diving turn but will not spin.

I hope this helps.