First, I’m wondering how much stiffer a 1515 is than a 1010 rail? Cross
section is 50% more, so approximately double?
One of my last fights over a year ago now (way too long ago) was a K1275R off
one of the back pads using a 1010 rail. The rocket went noticeably West
immediately after leaving the rail and it wasn’t the wind. Luckily, the rocket
landed close to the pad because of the wind during descent. One time the wind
really helped.
There’s always a lot of discussion about rocket stability, but think about how
important a reliable launch pad is. Of course, what engine in what rocket is
very important to how massive/stable the pad must be and how long the guiding
structure should be. Regardless of size, I think there is some occasional
thrust vectoring with AP engines that takes place moments after ignition that
seems to stabilize. What would be the reason that some rockets left the rail
in the Punisher drag race at an angle? I’m curious if other people believe
momentary thrust vectoring occurs?
If you are going over say 10K’ in a location like Lucerne Dry Lake, you need to
be reasonably sure that the rocket is stable (of course), and that it’s going
to fly in the direction you choose.
I’ve been considering launch pad designs for several years, and checked out all
the custom pads at the last two BALLS launches I’ve gone to. Some are really
cool with elaborate pad leg designs and lifting mechanisms but the ones with a
sturdy/stiff launch rail adequately supported along its entire length seem the
best to me. This is my opinion, and I might be a little jealous of the money
some spend on their launch pads.
I’m considering purchasing a 12’ x 5” utility trailer for the base of a launch
pad that would also be a platform for a test stand. The pad would use the
triangular aluminum tower material that seems to be popular for many large
launch pads. A link follows that shows a base for an antenna tower. I would
like to know if anyone else is interested in participating in the construction
of a large launch pad/test stand. It would serve as our launch pad/test stand
at ROC and FAR launches and be very useful for XPRS/BALLS.
http://www.dipolnet.com/footing_for_aluminum_antenna_tower_E9151.htm
Richard Dierking
