It was a Loc Precision 50 inch parachute with spill hole. There is a preset for that parachute in open rocket which is what I used. The weight of the actual rocket and the open rocket Sim were almost identical. So I’m not sure why the impact speed was higher. The main was laid out nicely on the side of the road. No tangles. Rocketry is hard.
Altimeter data. The two RRC2L's were remarkably close in their data points. Main and drogue decent rates were identical. 50 fps under drogue, 24 fps under main.
Just an fyi, that is way to small of a loc chute. On a 9.5lb rocket they recommend a 60" chute.
I don't think the RRC2's record that. I didn't see it in the log using the LCD. But the peak velocity was considerably lower. 436 mph vs. 502 in OR.
It was 7 lbs 5 oz. without the motor. So a 3 grain CTI case and the residue left inside added to that. Borderline, but I went with the 50" due to the tight 3" airframe and just figured, "What's a few more miles per hour?"
I bet it was close to 30fps
You can figure it out from the video timing by assuming the deployment altitude was where you set it. You were on the main for about 26 seconds, so if your deployment was set at 500 feet, that's 500/26 = 19.2 FPS.
Both altimeters logged 24 fps under main.
Any time there's weather cocking you end up with a horizontal component to velocity. The altimeter only looks at vertical movement.
Obviously if you have a recording altimeter you can linear-fit the altitude readings once under main and get a better value. As it happens, the RRC2L reports the average descent rate under main and I presume it's doing something like this internally. At any rate, any approximation from real data, even with assumptions, has got to be better than predictions from a very simple parachute model.
