- This topic has 42 replies, 15 voices, and was last updated 15 years, 11 months ago by
Rocketwhiz.
Rocketwhiz.-
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John A. Wilke
I landed 7.28 miles from the flight line. Never once lost signal. It was about 2 inches from where the GPS said it was 8) I’d never have looked within 4 miles of where I landed had I been using a transmitter. I’d never have found the rocket without GPS, period.
BTW, my dual deploy worked – main did NOT come out up top. Flight data and other anecdotal evidence confirmed that.
Jeroen and I looked at numerous web pages Saturday AM that said the jet stream had moved south. Clearly, that was not the case. I got swept waaaaay downwind. I wonder how much altitude I lost due to getting tipped over as I slowed down up top?
edward
I wonder how much altitude I lost due to getting tipped over as I slowed down up top?
24′ 🙂
Edward
Adrian
I landed 7.28 miles from the flight line. Never once lost signal. It was about 2 inches from where the GPS said it was 8) I’d never have looked within 4 miles of where I landed had I been using a transmitter. I’d never have found the rocket without GPS, period.
BTW, my dual deploy worked – main did NOT come out up top. Flight data and other anecdotal evidence confirmed that.
Jeroen and I looked at numerous web pages Saturday AM that said the jet stream had moved south. Clearly, that was not the case. I got swept waaaaay downwind. I wonder how much altitude I lost due to getting tipped over as I slowed down up top?
John, So what did you fly, and how high? What direction was the 7.28 miles? Any landowner issues?
edward
You need my drop like a rock drogue (36″ parachute with a 14″ spillhole) 🙂 The descent rate under drogue was 106 fps, only took a little over 3:45 to come down. Still decided to drift 2.9 miles out.
Edward
John A. Wilke
I didn’t have a drogue. None. Just shock cord. When you get into 250 knot winds, you have issues….
I can count on one hand the number of times I’ve used a drogue chute or streamer. I typically come down as fast as possible
edward
I read a paper a while back about parachutes and talked to a rigger friend of mine who dropped cargo out of planes. The paper said that in some situations you can get something to fall faster with a parachute. If you get everything to line up you have less exposed area than if you fell sideways.
The other recovery method I’ve heard of used was from Nick Anderson of (now out of business) Aerosleeves. He would take a minimum diameter rocket, and go past apogee and let it start to descend ballistically. At about 1/2 the flight altitude he would kick the motor out the back with a small (emphasis on small), durable drogue. This would slow it down until your main altitude. I saw data on 5 J570 flights that were performed like this and a couple 54mm flights. It looked like it was only for the brave 🙂 It took him 2 rockets to realize you had to kick the motor out and not split the rocket – he turned 2 rockets to confetti when they split and tried to change direction.
Might be something to try with a 4-5k rocket when there is a low populated launch angled well away from the crowd.
Edward
Chris LaPanse
I agree about the “drop it as fast as possible” comment – my Amraam had a descent rate of 180fps under drogue (somewhat accidentally though – I’m not sure what happened, but normally it is somewhere around 110fps instead). Total flight time was less than 3 minutes, with descent time from 17k to the ground of just a hair over 2 minutes.
Kenneth Reilly
We did recover the Thor, but not until Sunday morning. The reason for the discrepancy between the GPS reading and the actual landing spot became obvious after downloading the tracks. The Thor track ended roughly 1500′ above the ground. Apparently, the shock of the main deployment jarred the battery loose and knocked it into the transmitter body, putting it out of commission. I estimate that the shock load both when the charge fires and when yhe nose reaches the end of the shock cord could be in excess of 100 G’s. Battery mounts should be ruggedized accordingly.
John A. Wilke
Ken, that is a very good point (about battery mounts). I don’t trust them anymore. I use black tape and call it good, even on the most aggressive of boosts…
Chris LaPanse
I think I figured out why my drogue descent rate was 180fps – I was looking over the data, and the charges weren’t nearly as energetic as normal. My apogee separation was somewhat delayed, and only reached a peak of 11G at separation. For comparison, on my last flight, it reached in excess of 50G at charge ignition, and reached it almost instantly. I’m somewhat wondering if my charge burned slowly/incompletely due to the high altitude – that’s the highest I’ve gone by a solid mile or so, and air pressure is only 40% of sea level or so.
John A. Wilke
edward
Adrian
Chris LaPanse
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