I've had the dubious privilage of adding another data point to the ongoing
Estes D motor ejection problem thread. (Polite applause from the audience)
Thank you, thank you very much.
Friday I finally finished the Big Daddy I've been working on for the past 3
weeks; the first kit I've put together in 25 years. It turned out so nice
I was a bit hesitant to fly it, but I didn't build it to hang from the
ceiling so Sunday afternoon loaded up the launch gear and headed out.
Carefully prepped the bird for flight and scored the end plug on the D12-5
just to be safe. Launch was normal but the rocket weathervaned pretty
badly and was well on its way down when ejection occurred. The shock cord
separated about an inch from the engine mount anchor; the nosecone drifted
down on the chute while the body tumbled in, fortunately landing in heavy
weeds with no damage. Glad I used basswood for the fins. I should have
taken this as a sign and gone home for the day, but nooooooo....
Lesson learned: Use heavier shock cord than that supplied in the kit.
After mounting a longer, heavier shock cord, decided to try a D12-3. Once
again scored the end cap. Launch was textbook; perfectly vertical. It
reached maybe 300 feet, gracefully arched over and headed back down. I was
counting the seconds from engine cutoff and by the time I reached "six" it
was obvious that things would not turn out well. No evidence of ejection
at all. I'd never witnessed a lawn dart before and the rocket's
acceleration on descent was really very impressive. It actually "whooshed"
during the final leg of the descent and impacted about 40 feet from the
launcher. I was stunned and had flashbacks to the very first flight of the
first rocket I ever built, that CATOed spectacularly about 10 feet up back
in around 1972....
Here are before and after pics:
A post-mortem revealed no end cap remaining in the motor tube, but that may
be due to the impact. It just appears that the ejection charge was light.
Motor date code was 4B4.
Not sure if I'll attempt a rebuild, but after this and all I've read in
r.m.r., I am *finished* with Estes D's. Never again. Period. End of
discussion. Any suggestions on 24mm composite motors?