Model 4 rudder install? Speedster vs non airfoil

[klamath101]

The build manual I have wants 1.5 inch gap between vertical and rudder at the top and 2.3 inches gap on the bottom. Just wanting to verify that correct and why the slight angle.

[FoxbuilderWill]

Well I'm guessing here but I think it's an educated guess.

Since the chord of the rudder is larger at the bottom than the top that means the airfoil is thicker at the bottom than the top requiring a larger radius on the leading edge

[klamath101]

I chose not to airfoil the vertical or rudder would you still suggest the offset or a parallel install?

[jiott]

I would think a parallel install would be better for a non-airfoiled tail. To keep the gap minimized and better looking.

[klamath101]

I’m going to look it up after this but what is a recommended method of gap sealing, rigged it today with 1.5 inch top and bottom.

[t j]

My classic 4 kit was delivered in 1994. There was a hard foam rudder gap seal for a Model 5 in the crate. It was already rounded on the leading edge to fit snug against the tail post. I just cut about 3 inches off one end and cut the notches for the rod ends. It filled the gap perfectly. You could probably make a similar gap seal out of balsa wood.

If you mount the rudder parallel to the tail post and close, check the operation of the rudder cables and rudder stops to be sure they operate correctly.

[klamath101]

Thanks everybody ended up going through pics before tear down and guessing originally it was parallel tough to tell on old pics decided to go parallel. One other odd thing book shows four swivel joints this build only has 4. Headed to town looking for rudder return springs this morning to finish up the rigging.