V tail design
 

Hi guys,

I know V-tails are usually designed with 110 degrees dihedral to provide a good balance between effective horizontal and vertical areas. One question though - when sizing the surfaces do I simply use projected area, i.e. if I want a 22% stab do I simply design the projected top view of the V-tail to have 22% of the wing area? Seems intuitive but thought I'd ask anyway.

Thx

MJD

RE: V tail design
 

They may be built that way, but that's not "designed".

RE: V tail design
 

http://www.charlesriverrc.org/articl...tailsizing.htm

RE: V tail design
 

Re: http://www.charlesriverrc.org/articl...tailsizing.htm

That's handy, thanks!

Re:
V-tails are usually designed with 110 degrees

They may be built that way, but that's not "designed".

Well, sure it is, but the designer might not have employed any engineering. Anyhow, for stab areas of 20-25% 110 degrees yields a functional though perhaps not ideal vertical stab area, so I suppose that is why it is one of those old rule of thumb principles.

MJD

RE: V tail design
 

You see 110 degrees because people copy without trying to comprehend. Beech use 118 degrees on the Bonanza. Gliders usually need the more acute angles.

RE: V tail design
 

If your lazy, like me, I have a [link=http://www.zwei.net/designs/Misc%20Stuff/TailAngle.xls]spread sheet[/link] that will help you find the angle. It follows the formula found in another discussion.

RE: V tail design
 

Thanks! I'll do the calc myself so I (hopefully) remember how next time, but I'll keep that handy anyway.

MJD

RE: V tail design
 

???

RE: V tail design
 

.
I think it's a reference to the 110 degrees, which is commonly seen.
Johnny uses 110 degrees, so I will too..
Without knowing -why- the 110 degrees is used, it's not "design".
The vee-angle is predicated on the airplane use.
A rudder-elevator airplane might use 90 degrees, for the most effective rudder response.
An aileorn plane which doesn't use the rudder as the primary turning control can relax the vee to 110 degrees, giving the elevator more authority.