Slanted vertical stabs

[Shakey Jake]

I've noticed that some of the jet type planes have their vertical stabelizers slanted out at an angle from center. Others, like the Black Bird have them canted in at the top. Is there any real reason for doing this. I'm building one now and am about to mount twin fins streight up. Am I missing out on some advantage that I should be aware of?

[Sparky Paul]

What Mach number are you planning to fly at?
If it's below 2.0, canting the fins won't buy you much.
The fins on the SR are canted inward to reduce the radar signature of the plane.
The verticals are canted to take advantage (ususally) of the fuselage vortex.
On the F-18, they also serve as auxiliary elevators when it's being catapaulted.

[BMatthews]

I suspect the F18 also had issues about surface interferance much like the separation spacing on the wings of a biplane. If you compare an '18 to a '15 or a '14 the bigger planes have more spacing at the bases of the fins.

I actually read that the rudders in on the '18 was more for drag reduction during pullups. But I guess they would add some up elevator vector when bent in hard during catapults.

[Shakey Jake]

Sparkey,
About the speed of a Maching bird.;) Guess I don't need to worry about that. Streight up it is then. Thanks fellas.

Shakey