Nytrunner
Pop lugs, not drugs
Good chances of the club allowing it as an L1? They should, it seems stable enough and built well.
Super Flying Umbrella Build Thread (Level One?)
- Thread starter ScrapDaddy
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ScrapDaddy
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The good news is that the flight went really well!
The bad news is the landing did not
A couple of things went into this according to my autopsy.
1) The field was harder than I was used to flying out of (I'm used to flying out of a soggy swampy backyard), and it landed on a hard patch of clay.
2) The rocket appeared to be hit by a wind shear about 20ft off the ground, causing it to swing back and forth, it was in the motion of swinging into the ground which exacerbated things.
3)The rocket landed in a way where all of the force was put onto the shorter, weaker vertical fin, at which point popped off and tore off the two horizontal panels it was attached to.
4) The parachute was likely undersized given all of these conditions, the rocket was 2 pounds 4 ounces loaded, and about 27 ounces w/o propellant, and it was on a 30 inch parachute. (The TFR chart says this would be fine, but other calculators suggested at least a 36" chute, and I should have played it safer given the rocket was only going 350', so drift wasn't an issue, but I was worried about fitting the chute in the nose cone, which was poor design since when I originally designed it the I200W didn't fit, causing the parachute being limited to the nose cone)
5) It appeared from the joints that I was quite sloppy with the CA when I was tacking the fins together. These bits of CA ended up between the epoxy fillets and the plywood, limiting the bond strength to that of the CA. Other spots revealed that the epoxy had stuck and taken a thin layer of plywood with it, showing TTW was likely needed.
6) I think the rocket having flown 27 times prior before my cert attempt wasn't the best idea either, being subjected to a total of 4 lawn darts and countless hard landings before hand.
Basically: A last minute design adjustment(fitting the I200 by putting the chute in the NC) resulted in me placing a smaller chute than was optimal, leading to a fast decent onto a fin can that probably should have been mounted TTW given the surface area. Poor technique tacking the fins with CA weakened the epoxy bonds, and field conditions (a steady 10-15mph wind, and a hard patch of ground) made things worse.
Well I am a bit bummed, but I was fully aware that taking anything besides a 3FNC kit would introduce increased chances of failure, and I think I learned quite a bit from this attempt. The umbrella shall fly again, but I think I have another idea for a second level one attempt
The bad news is the landing did not
A couple of things went into this according to my autopsy.
1) The field was harder than I was used to flying out of (I'm used to flying out of a soggy swampy backyard), and it landed on a hard patch of clay.
2) The rocket appeared to be hit by a wind shear about 20ft off the ground, causing it to swing back and forth, it was in the motion of swinging into the ground which exacerbated things.
3)The rocket landed in a way where all of the force was put onto the shorter, weaker vertical fin, at which point popped off and tore off the two horizontal panels it was attached to.
4) The parachute was likely undersized given all of these conditions, the rocket was 2 pounds 4 ounces loaded, and about 27 ounces w/o propellant, and it was on a 30 inch parachute. (The TFR chart says this would be fine, but other calculators suggested at least a 36" chute, and I should have played it safer given the rocket was only going 350', so drift wasn't an issue, but I was worried about fitting the chute in the nose cone, which was poor design since when I originally designed it the I200W didn't fit, causing the parachute being limited to the nose cone)
5) It appeared from the joints that I was quite sloppy with the CA when I was tacking the fins together. These bits of CA ended up between the epoxy fillets and the plywood, limiting the bond strength to that of the CA. Other spots revealed that the epoxy had stuck and taken a thin layer of plywood with it, showing TTW was likely needed.
6) I think the rocket having flown 27 times prior before my cert attempt wasn't the best idea either, being subjected to a total of 4 lawn darts and countless hard landings before hand.
Basically: A last minute design adjustment(fitting the I200 by putting the chute in the NC) resulted in me placing a smaller chute than was optimal, leading to a fast decent onto a fin can that probably should have been mounted TTW given the surface area. Poor technique tacking the fins with CA weakened the epoxy bonds, and field conditions (a steady 10-15mph wind, and a hard patch of ground) made things worse.
Well I am a bit bummed, but I was fully aware that taking anything besides a 3FNC kit would introduce increased chances of failure, and I think I learned quite a bit from this attempt. The umbrella shall fly again, but I think I have another idea for a second level one attempt
LithosphereRocketry
Pining for the Fjords
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Still no Cesaroni? They have an H180 Skidmark that would be amazing... Even the I200 was pretty loud at that altitude. Just think of what a Skidmark would sound like!
This is very reminiscent of Andy Schector's 4" Grim Reaper build. He flew his creation at LDRS 19 in 2000 on an M1419. The rocket sported a Saucer fin set up and a skull for a nosecone. Despite the 4" M-class motor, the flight was a low altitude event. Very cool as I remember it.
