Thank you David for sharing your experience. That they tend to open softly sounds great, this will reduce the shock load. Well I think, I am on the right way. Anyway great pictures. Awesome. What was the take-off weight and motor of the two flights?I've got several of their standard chutes, no flights with data recorded hit at high speed, but I've had delays go long on smaller rockets, in the 3 pound range with a 3 foot rocket man chute. The design in general lends itself to a gradual opening.
In my experience, they tend to open "softly" not just a big slam. Of course, the rest of the recovery system needs to be up to the task, but I'd think these chutes can absolutely handle the speeds you're looking at, if sized and mounted properly.
Hey Edward, ok I could follow you: I use:One way to calculate Isp is to take the total impulse divided by unit weight of propellant
I converted everything to imperial units.
10,000 Ns = 2248 lbf
5.0kg oxidizer + 1.5kg HDPE fuel = 6.5kg propellant = 14.33 lb
2248/14.33 = 156s
Thrust (F)= Mass-Flow-Rate (m'_p) * Effective Exhaust Velocity (c*)
Well I get the same results. So anyway both ways work.
So the above image shows the first 0.5s of test #005_02 -> it was a 8s run with 4.5kg total fuel mass burned. The image shows the peak thrust with approx. 1600N - the average across the 8s was around 1260N:
So its doing quit well ... in the beginning I´ve just thrown in some approx. numbers because it was about the chute. If you want do discuss the engine in detail we could switch the topic and go somewhere else (not in recovery....)