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HPR Glider Driver
- Joined
- Jun 9, 2012
- Messages
- 2,144
- Reaction score
- 73
Update 2014-06-22: this rocket has now flown on motors from E16 to J510, 6 impulse classes. at 1,162NS and 23", J510 is the largest-impulse certified 38mm motor that is commonly available. Bluefin Tuba can now officially take any motor that fits in the fuselage.
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I'm building a minimalistic 38mm MD tube-fin rocket out of Blue Tube. If you think the name is a bad pun, I challenge you to come up with a better one!
I've had a lot of fun with PVC and ABS tube-fins. My 2 3/8" ABS Black Piper flew on everything from F50 to J575. It has sadly met with a non-performing delay on the J575 and lake-staked at BALLS. Gary was kind enough to replace the reload, and now I need a new simple, motor-eject tube-fin to replace that one.
As with Black Piper, my goal is to find how far I can push a basic tube fin design without reinforcing it. Bluefin Tuba is lighter and less draggy than Black Piper and simulates surprisingly well on motors as small as E15 (OR predicts 600' feet). I'm looking forward to HPR season finally starting in NorCal to see how it performs on larger motors.
Construction is super basic. I use a miter saw with plywood (180-tooth) blade to cut 2" fins off a 48" standard piece of BT. I use the entire remaining 35 1/4" for fuselage.
Even this fine-tooth blade produces fuzz, which I clean up with a knife in the inside and 80-grit on the outside. I like to orient my knife along the fibers in BT winds to avoid digging in.
I sand off 3 stripes on each fin about 30˚ apart. On the BT I simply sand an entire band instead of trying to measure off 6 separate stripes.
I use yellow glue on BT. I apply it in slightly more liberal quantity than usual, so that it makes a fillet when it dries. Glue lines are visible in the last shot. Once yellow glue is dry, I make a second-layer fillet with Titebond Molding glue. I assemble my tube-fins in 3 sub-assemblies which I let dry before continuing on. I find it the easiest to keep all fins in alignment this way.
Ari.
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I'm building a minimalistic 38mm MD tube-fin rocket out of Blue Tube. If you think the name is a bad pun, I challenge you to come up with a better one!
I've had a lot of fun with PVC and ABS tube-fins. My 2 3/8" ABS Black Piper flew on everything from F50 to J575. It has sadly met with a non-performing delay on the J575 and lake-staked at BALLS. Gary was kind enough to replace the reload, and now I need a new simple, motor-eject tube-fin to replace that one.
As with Black Piper, my goal is to find how far I can push a basic tube fin design without reinforcing it. Bluefin Tuba is lighter and less draggy than Black Piper and simulates surprisingly well on motors as small as E15 (OR predicts 600' feet). I'm looking forward to HPR season finally starting in NorCal to see how it performs on larger motors.
Construction is super basic. I use a miter saw with plywood (180-tooth) blade to cut 2" fins off a 48" standard piece of BT. I use the entire remaining 35 1/4" for fuselage.
Even this fine-tooth blade produces fuzz, which I clean up with a knife in the inside and 80-grit on the outside. I like to orient my knife along the fibers in BT winds to avoid digging in.
I sand off 3 stripes on each fin about 30˚ apart. On the BT I simply sand an entire band instead of trying to measure off 6 separate stripes.
I use yellow glue on BT. I apply it in slightly more liberal quantity than usual, so that it makes a fillet when it dries. Glue lines are visible in the last shot. Once yellow glue is dry, I make a second-layer fillet with Titebond Molding glue. I assemble my tube-fins in 3 sub-assemblies which I let dry before continuing on. I find it the easiest to keep all fins in alignment this way.
Ari.
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