|Reliant's flight profile from the PNUT altimeter (Click to enlarge).|
2) The online descent rate calculations did an excellent job predicting the descent rates - the choice of two 12" octagonal parachutes was perfect for egg capsules weighing close to 300 grams. I got measured rates of 22 and 23 feet per second, which are right on the money.
3) The BAMA Recovery Systems TARC parachutes took the stress, and they are octagonal, which increases the parachute drag. Plus they are lighter and cheaper than comparable Top Flight parachutes.
4) TARC teams using F32's in BT-70 rockets may be adding a fair amount of ballast this year to drop altitudes. Do lots of sims and choose your motors carefully based on the numbers. Watch the delay times - 6 seconds is close, 4 is way too short. Ejection should occur just past apogee, not before (as in the Reliant flight profile depicted above).
5) You can do this year's challenge on a cluster of 2 Estes E12-6's - Artemis' flight proved this. The question remains as to how consistent black powder clusters are from flight to flight. If you have to cluster, 2 motors are the easiest (naturally).
6) If you use the Perfectflite Firefly (cheaper, smaller, and lighter than the PNUT), get the field display unit. The flashing LED is tough to read on bright sunlit days.The Firefly is not a logging altimeter, but is kinda like the Jolly Logic Altimeter 2. Here's the data from Artemis' flight:
- Apogee: 871 feet
- Speed: 428 ft/sec
- Time to Apogee: 7.4 sec
- Flight Time: 44.6 sec
- Descent rate: 23.4 ft/sec
- FDD Battery: 3.06 V
- FF Battery: 2.63 V
8) The Apogee egg cushions work well and are not that heavy. I flew the 2 egg cushion and a 1 egg cushion in each payload section.
9) Pack your parachutes very carefully - I used Estes wadding to keep the chutes separated in the body tube. You do not want the egg capsule parachutes tangling up - that would be bad.
That's what immediately comes to mind - hopefully some TARC teams find something useful in this post.