rharshberger
Well-Known Member
Last Saturdays launch (18 April 2015) was both and exciting and a little disappointing. The Crayons flew (and one crashed) for the first time.
Build thread is here: https://www.rocketryforum.com/showthread.php?123496-Crayon-Bank-Rocket-build-times-two
Getting the Red one in the air was an interesting series of events ranging frome a GSE failure (pad relay was bad), to me failing to vent the redcap properly and the igniter popping out (thanks to D.King for his assistance and guidance).
Flight 1
When we finally did get Red in the air it was a beautiful flight on a AT 29/40-120 G76G to 500' per the OpenRocket Simulation and confirmed via the MissleWorks RRC3 in the nose cone. It went downhill from there (pun intended) the delay was too long and the ejection charge fired 30 or so feet above ground, the 20' kevlar shock cord and parachute were attached to the NC, the chute started to deploy at about 15 feet, but the 20' shock cord allowed the airframe to slam into the ground basically at full velocity. After action review, the delay wasn't drilled properly due to the fact the bit on my delay drilling tool was loose, so the delay was too long. The rockets boosted fine under the G motors used, but will require electronic ejection in the future with these motors as the delays cannot be shortened enough. Damage was 2 cracked fins and a crimped body tube, due to location of BT damage this rocket will not be flown again (most likely).
Flight 2
L1 Certification Flight
The Pink Crayon things went much better. Motor was a AT RMS H123W to 1200' again nearly perfectly on the sim from OR and confirmed via the RRC3, it was a great flight. Chute deployed properly (thanks to my dear wife the seamstress) it was a 48" twelve gore with 6" spill hole Red and White panels, a beautiful chute, with a descent rate of 21 fps according to my math. The rocket landed about 2500' SE of the launch area in the sod near Frontier Rd.
Flight 3
The Pink Crayon flight 2 was on a AT 29/40-120 G64W once again to 500'. Deployment was again via motor ejection. I realized that my RMS Delay Drilling Tool had an issue and L. Kennedy (I hope I got the name right) was gracious enough to loan me his to adjust the delay. It was almost the same scenario as Reds first flight only this time the delay was shorter and the chute deployed in time to keep the rocket from hitting the ground too hard.
Conclusions
These rockets weighed about 58 to 60 ounces each, motor delays cannot be adjusted short enough if flown on a G motor less than a G138, and require electronic ejection. 1 gram of 4Fg BP was used and that was plenty, especially since shear pins were not necessary. The rockets were definitely built tough enough as the Red one actually held together really well given an impact velocity of over 200 fps. I would definitely fly these again on G motors only with electronic ejection, since they are low and slow its a good show for the crowd.
While I had no intentions of making my cert flight on a Pink Crayon fate plays dirty tricks, all in all it was a successful day. Thanks to all the members here who have contributed to my knowledge base allowing me to be successful.
Rich.
Build thread is here: https://www.rocketryforum.com/showthread.php?123496-Crayon-Bank-Rocket-build-times-two
Getting the Red one in the air was an interesting series of events ranging frome a GSE failure (pad relay was bad), to me failing to vent the redcap properly and the igniter popping out (thanks to D.King for his assistance and guidance).
Flight 1
When we finally did get Red in the air it was a beautiful flight on a AT 29/40-120 G76G to 500' per the OpenRocket Simulation and confirmed via the MissleWorks RRC3 in the nose cone. It went downhill from there (pun intended) the delay was too long and the ejection charge fired 30 or so feet above ground, the 20' kevlar shock cord and parachute were attached to the NC, the chute started to deploy at about 15 feet, but the 20' shock cord allowed the airframe to slam into the ground basically at full velocity. After action review, the delay wasn't drilled properly due to the fact the bit on my delay drilling tool was loose, so the delay was too long. The rockets boosted fine under the G motors used, but will require electronic ejection in the future with these motors as the delays cannot be shortened enough. Damage was 2 cracked fins and a crimped body tube, due to location of BT damage this rocket will not be flown again (most likely).
Flight 2
L1 Certification Flight
The Pink Crayon things went much better. Motor was a AT RMS H123W to 1200' again nearly perfectly on the sim from OR and confirmed via the RRC3, it was a great flight. Chute deployed properly (thanks to my dear wife the seamstress) it was a 48" twelve gore with 6" spill hole Red and White panels, a beautiful chute, with a descent rate of 21 fps according to my math. The rocket landed about 2500' SE of the launch area in the sod near Frontier Rd.
Flight 3
The Pink Crayon flight 2 was on a AT 29/40-120 G64W once again to 500'. Deployment was again via motor ejection. I realized that my RMS Delay Drilling Tool had an issue and L. Kennedy (I hope I got the name right) was gracious enough to loan me his to adjust the delay. It was almost the same scenario as Reds first flight only this time the delay was shorter and the chute deployed in time to keep the rocket from hitting the ground too hard.
Conclusions
These rockets weighed about 58 to 60 ounces each, motor delays cannot be adjusted short enough if flown on a G motor less than a G138, and require electronic ejection. 1 gram of 4Fg BP was used and that was plenty, especially since shear pins were not necessary. The rockets were definitely built tough enough as the Red one actually held together really well given an impact velocity of over 200 fps. I would definitely fly these again on G motors only with electronic ejection, since they are low and slow its a good show for the crowd.
While I had no intentions of making my cert flight on a Pink Crayon fate plays dirty tricks, all in all it was a successful day. Thanks to all the members here who have contributed to my knowledge base allowing me to be successful.
Rich.
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