Flight #: 13 Date: 9th of June, 2002 Venue: UKRA 2002, Pete's Rockets, Heckington, Lincolnshire R-DAS Type: R-DAS Compact R-DAS firmware: 3.2 R-DAS Recorded Altitude: 1762 feet (534 metres) Apogee - Charge Firing Delta-t: 1.3 seconds Apogee - Charge Firing Delta-h: 30 feet (9.1 metres) Descent Rate at Apogee Deployment: 23 feet per second (7 metres per second) R-DAS Flight Mode: Apogee & Main Ejection (breakwire launch detection & smart recovery) Total Time of Flight: 70 seconds Apogee - Charge Firing h Variance: 0% Launch Vehicle Diameter: 2.6 inches Launch Vehicle Length: 6 feet Launch Vehicle Propulsion: Hypertek J-250 Hybrid 440/54-125-J (0.125 injector orifice) Fins: 3 clipped swept deltas (Aerofoiled) Launch System: Rail Launch Finish: Semi-painted Ejection Method: Electronic Deployment using apogee charge in SafeEject canister, then main charge in SafeEject canister Ejection Ignition Type: Daveyfire igniters (electric matches) Launch Vehicle Mass: 2.5 kg (vehicle with hybrid motor but no oxidiser loaded) Total Propellant Mass: 405 grams Total Loaded Motor Mass: 1294 grams Total Impulse: 745 Newton seconds Optimum Theoretical Burn Time: 3.00 seconds Actual Useable Burn Time: 3.70 seconds
Comments The third flight of the Hephaestus rocket, launched on the Hypertek J-250 hybrid rocket motor (using a 440cc oxidiser tank). The rocket was angled about 10 degrees from vertical into the wind, to account for the wind direction. As a result, the rocket arcced and weathercocked quite badly - certainly far worse than I had anticipated. The apogee was passed at some speed, although the R-DAS managed to cope admirably, and successfully separated the rocket for tumble recovery. The PML 44" main chute deployed perfectly again, bringing the rocket down softly once more. Unfortunately, the rocket descended into a field of crops, and the RF transmitter had just decided to die, so the recovery of the rocket took quite a few hours of wandering around a field listening for the audio beepers. This was the point when I realised I needed to use louder beepers in future. The R-DAS used breakwire launch triggering with smart recovery. This option was again chosen because the oscillation in Hypertek motor combustion has been known to result in irregular launch triggering of the R-DAS. The breakwire and smart recovery option worked perfectly, and both ejection channels fired on cue, with the main parachute returning the rocket softly. A breakwire from Airborne Engineering Limited was fitted, and 2 sounders were also carried on the flight, along with a 433 MHz RF tracking beacon.
Thrust Section of Flight