I've put together a 4' long rocket based on Estes BT-50 tubes (.95"
diameter). It has four fins that seem quite adequate in size (at least to
my untrained eyes). I compare my rocket to the pictures of an Estes "Mean
Machine," and my fins seem much larger. The problem is that I can't get
this model to pass the swing test. I made a longer basswood nosecone in an
attempt to put more weight forwards, but that wasn't enough. The rocket
always stabilizes in a perfectly vertical position, never nose-forwards. I
am now thinking of attaching four more fins to the rocket, but it seems
like overkill.
My question is: how necessary is it for a rocket to pass the swing test.
Some part of me wants to believe that such a long rocket is just too big
to get into a proper trajectory on the end of a tether.... something about
the length extending well well out onto the tangent of the circle, rather
than following the arc tightly.
Another question: how likely is it that a rocket that flunks the swing
test will in fact be stable under power?
And on another unrelated topic: Is there some source of material that will
make sturdy, low-weight launch lugs, for both 1/8" and 3/16" rods? Buying
the Estes lugs seem kind of silly, especially since I take pride in using
non-conventional materials. Any ideas?