Fin Alignment

Fin Alignment

Post by Bill Nels » Fri, 27 Oct 1995 04:00:00



: My friend says I'm a typical "nit picking engineer", and that fin alignment
: isn't all that critical. I disagree, but I don't know enough about rocket
: aerodynamics to prove it.

Unless you are going for maximum performance, or your rocket is going to
reach high velocities, then alignment is not critical. The worst that would
happen is that the rocket will spin or "cone" as it climbs.

A variation on the Estes "doorframe" alignment line marking has always worked
well for me - with the angle to the tube being eyeballed.

I actually prefer a slow rotation on my rockets - especially those that will
be using a long burning motor.

: What are acceptable tolerances for alignment along the body tube ?
: What are acceptable tolerances for the deflection angle from the tangent
: of the body tube ?

See above. There have been thousands of grade school age children who have
slapped fins on the rockets at various crooked angles. Most of them fly
ok - even if not textbook perfectly.

Bill