DynaSoar
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- Mar 14, 2004
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This was my first heavy duty bird (heavy tube, ply fins, etc.).
I was impressed at the sheer strength of the materials. Obviously it could handle more than the Gs which were it's highest rating. I beefed up the motor mount for this purpose. I epoxied on some slabs of body tube scrap to spread the stress on the motor tube to the ends of the mount rings rather than depending on the ID/OD surface epoxy. I also loaded up the lower MMT ring with enough epoxy to run out before inserting it, so it would bond to the main tube from above and below.
Rather than epoxy on glass for fin reinforcement I just gave it good, thick fillets, at least 1/4" thick. I used Devcon 5 minute epoxy throughout. I wish I'd had some syringes to work with, but managed fairly well using only 1 foot by 3/16" bamboo skewer stick for stirring and application.
I spent anout 1/2 hour planning, adding my estimates of how much epoxy to mix when to their (rather skimpy) instructions. It paid off. It went from parts to primer in less than 6 hours.
My two complaints with this bird, one probably specific to my parts, the other to the design:
1. The cone didn't fit precisely parallel. I inserted the cone into the payload tube and gave it a roll test. It wasn't a smooth roll. I figured out where the low spot was and beefed up the shoulder a bit. That took care of it.
2. The parachute is maybe 12 inches, is thick cloth and has thick cords. I can't believe they expect this thing to safely lower a bird that's going to be pushing a pound when loaded. As always, I put the chute on a locking snap swivel, so it'll be trivial to swap chutes in and out. I'm just afraid to try this one by itself. Maybe with a second 12" maybe, or one 18".
I was impressed at the sheer strength of the materials. Obviously it could handle more than the Gs which were it's highest rating. I beefed up the motor mount for this purpose. I epoxied on some slabs of body tube scrap to spread the stress on the motor tube to the ends of the mount rings rather than depending on the ID/OD surface epoxy. I also loaded up the lower MMT ring with enough epoxy to run out before inserting it, so it would bond to the main tube from above and below.
Rather than epoxy on glass for fin reinforcement I just gave it good, thick fillets, at least 1/4" thick. I used Devcon 5 minute epoxy throughout. I wish I'd had some syringes to work with, but managed fairly well using only 1 foot by 3/16" bamboo skewer stick for stirring and application.
I spent anout 1/2 hour planning, adding my estimates of how much epoxy to mix when to their (rather skimpy) instructions. It paid off. It went from parts to primer in less than 6 hours.
My two complaints with this bird, one probably specific to my parts, the other to the design:
1. The cone didn't fit precisely parallel. I inserted the cone into the payload tube and gave it a roll test. It wasn't a smooth roll. I figured out where the low spot was and beefed up the shoulder a bit. That took care of it.
2. The parachute is maybe 12 inches, is thick cloth and has thick cords. I can't believe they expect this thing to safely lower a bird that's going to be pushing a pound when loaded. As always, I put the chute on a locking snap swivel, so it'll be trivial to swap chutes in and out. I'm just afraid to try this one by itself. Maybe with a second 12" maybe, or one 18".