#21
|
||||
|
||||
I also updated the Semi-Scale Saturn V Estes K-39 with separate engine fairings and both the plastic and balsa fins. Be sure to only include whichever set you are flying with. This simulation contains pods so it won't work in OpenRocket.
__________________
Bruce S. Levison, NAR #69055 |
#22
|
|||
|
|||
Quote:
__________________
Paul If we weren't all crazy, we would go insane - Jimmy Buffett NAR #87246 www.wooshrocketry.org |
#23
|
||||
|
||||
If the clear fins are left off and you just go with the small scale fins, any idea where the centre of pressure would be?
I have a K-39 that I built with 5 BT-5 engine tubes. If I knew the centre of pressure I could install 5 mini A engines and then add sufficient nose weight to bring the CG ahead of the CP. |
#24
|
||||
|
||||
Quote:
I remember reading somewhere sometime someone said with "stock" scale fins, if you balance it at the front of the second stage, it'll be stable. I can't recall exactly where or when I read it nor by whom... Later! OL J R
__________________
The X-87B Cruise Basselope-- THE Ultimate Weapon in the arsenal of Homeland Security and only $52 million per round! |
#25
|
||||
|
||||
Quote:
For the Estes Semi Scale Saturn V K-39 kit RockSim calculates a CP of 11.7602 inches from the tip of the nosecone on the escape tower with just the scale fins in place, an unstable situation by -0.50 calibers with a C6-5 motor installed. I had to put 1.5 ounces of weight into the BT-52 section to get a margin of 1.13, see attached RockSim file. I tried to create a simulation with the 5 x BT-5 motor tubes installed and using 2 centering rings; RockSim calculates a margin of stability of 1.11 calibers with 5 x A10-3T motors installed and 1.75 ounces of weight installed at the top of the BT-52 tube at the bottom of the balsa section. Since there is some uncertainty in this simulation, I urge you to use caution when making this flight for the first time, 1.75 ounces still might not be enough added nose weight for a stable flight especially on a windy day.
__________________
Bruce S. Levison, NAR #69055 |
#26
|
||||
|
||||
Bruce, that's just super! Thank you!
Joe |
Thread Tools | Search this Thread |
Display Modes | |
|
|