Tau Zero
03-29-2010, 11:53 PM
Okay, rocketry and RockSim fans! :cool:
Here's the information and RockSim file for the proposed SLS Prometheus. I'd like you to take a look at it, and give me your feedback on it.
You can see I've done simulations for the following motors, with the following results:
Motor ----- Max. Alt. ---- Dv -- Stable at:
C11-3 ------ 178 ft. ----- 4 fps -- 51"
D12-5 ------ 537 ft. ---- 12 fps -- 42"
E15W-7 ---- 1,737 ft. -- 12 fps -- 37"
F21W-8 ---- 2.387 ft. -- 13 fps -- 27"
G40W-10 --- 3,676 ft. -- 13 fps -- 19"
1) I saw the "Minimum velocity for stable flight reached at: 51.3382 In." for the C11-3, and responded in panic by specifying a 60" (5') long launch rod. As a result, I think that I shouldn't even bother suggesting that particular 24mm motor for this design.
2) If I specify a 48" (4') long launch rod, would you say that the remaining 6" is a comfortable margin for the D12-5's 42" minimum launch rod length needed for stability, or not?
3) Do you think that enough people use the remaining Aerotech motors to warrant releasing this design as a kit? Does that motor range make it desirable?
EDIT: Oops! If you change the "Static margin reference" to "Maximum frontal diameter" instead of "Nose cone base," that alters the results *very* slightly on the D and F motors, but not much.
As always, please post your comments on this thread. Thanks in advance!
.
Here's the information and RockSim file for the proposed SLS Prometheus. I'd like you to take a look at it, and give me your feedback on it.
You can see I've done simulations for the following motors, with the following results:
Motor ----- Max. Alt. ---- Dv -- Stable at:
C11-3 ------ 178 ft. ----- 4 fps -- 51"
D12-5 ------ 537 ft. ---- 12 fps -- 42"
E15W-7 ---- 1,737 ft. -- 12 fps -- 37"
F21W-8 ---- 2.387 ft. -- 13 fps -- 27"
G40W-10 --- 3,676 ft. -- 13 fps -- 19"
1) I saw the "Minimum velocity for stable flight reached at: 51.3382 In." for the C11-3, and responded in panic by specifying a 60" (5') long launch rod. As a result, I think that I shouldn't even bother suggesting that particular 24mm motor for this design.
2) If I specify a 48" (4') long launch rod, would you say that the remaining 6" is a comfortable margin for the D12-5's 42" minimum launch rod length needed for stability, or not?
3) Do you think that enough people use the remaining Aerotech motors to warrant releasing this design as a kit? Does that motor range make it desirable?
EDIT: Oops! If you change the "Static margin reference" to "Maximum frontal diameter" instead of "Nose cone base," that alters the results *very* slightly on the D and F motors, but not much.
As always, please post your comments on this thread. Thanks in advance!
.