Saturday, March 28, 2009

Launch Report #28

Today was a rather auspicious launch. I fired my first composite and reloabable motor, had my first sucess with a Copperhead, plus a sucessful flight test of my new nylon chutes. I also proved my machbuster to be stable and workable.

First came Mach My Day on an A8-3. It flew straight and fast off the pad, ejected just past, and came down safely about 100 feet from the pad. Next flight: D21-7.

Second came the GBU-24 Paveway III on an A8-3. Although it's a recommended motor for the rocket, it only went up around 120 feet and ejected at about 80. Fortunately, the 13" nylon chute deployed quickly and it cam down safely with only a small body tube dent. I don't think these nylon chutes have quite as much drag as plastic chutes, athough the larger ones seem to glide and generate lift, so for that size I might actually need the 18" chute.

Third was the Glider 2 on a B6-2. It wobbled a lot under power and seperated just after burnout, for a 15-second glide nonetheless. I'm thinking of adding a wire glider-retention mechanism that Trip Barber showed at NARCON.

Fourth was the Deltie Thunder on a D12. It was marked with D12-3, but as I suspected from the clay cap being nearer the end, it was actually a D12-7, and it ejected 3 feet off the ground. No real damage, although the glider neeeds more reinforcement. I'm gonna write a letter to Estes - they're known for being good about giving refunds for malfunctioning motors, and their faulty motor damn near killed a 30-dollar rocket. If the glider didn't already have CA reinforcemnt due to minor glide testing crashes, or if it hadn't ejected above ground, or if the ground was hard, then the glider would have been splintered balsa. I've filed an NAR Mess form for it. Oddly enough, the other two motors from the pack all performed fine with 3-second delays. Fortunately, the 1/4" rod pushed 8" deep into the ground provided a good solid launch rod, and sticking my other rods into the ground have it bracing against the wind. I also managed to place my leads so that neither glider I flew today tangled, even though both had large protruding surfaces.

My fifth flight was much better. It was my 24mm saucer on a D15-4 24/40 Blue Thunder reload. It ttok a few seconds for my low-current system to fire the Copperhead, which demands 3 amps, but when it fired the rocket rose fast and loud with very little smoke to around 120 feet. I ejected right at ground level; I wonder if it's ok to leave the ejection charge out for saucers for no ejection. The motor was easily twuce as loud an an Estes D12 - very impressive. For Es and Fs I'll extend my igniter leads to their full 45' length. I'm thinking I'll buy E18W reloads next rather than E28Ts - the Blue Thunder is nice, but I want the big white flame and smoke of White Lightning for other flights. i've also decided I need an aft closure wrench - tightening it really hurt! It rather stunk after flight, so I threw the spent parts out in a plastic bag then immediately cleaned it to minimize the smell. Pictures maybe coming later today (it's 2:42 am right now).

Since September: 125 motors on 102 flights, 629 Ns (96.85 I) total (11 Ns - an A plus a C or any D - puts it into J range); 5.04 Ns (0.8% C) per motor and 6.17 Ns (23% C) per flight.

No comments: