Jun 15, 2011

Rocksim 9 8" MLAS file

    Ok so I spent most of yesterday working of school stuff. But everyone needs a break right.  So seeing that I have the latest and greatest rocksim from Apogee, I spent some time designing /redesigning the MLAS. 
I found out something out about this model. You have to design it from the rear and move foward.  Rocksim doesn't like this MLAS, once you get the CP/CG relation reversed it is hard to fix.

But I goter  done and ran the sims.   
NOTE HERE)   the motors are not canted like ours so the true flight is still a best guess.  
But we managed to get ours to fly so it can't be to bad.  Im trying to import the file to my page but I can't seem to ge it done??
I will try to post it today.  oh yea almost forgot,  sims out at 652 ft with four single use 24 mm  Areotech motors


Tim Wilson said...

Try "derating" your motors to account for the cosine loss; i.e., create a "new" 24mm motor in RockSim with a thrust equal to that of the motor you plan to use less the amount lost due to the installation angle. That ought to improve your sims. Also, it's important to calculate CP using the RockSim method, not Barrowman. Barrowman is the default, but it won't get this short fat body right due to the base drag, which works in your favor (brings the CP aft). Good luck!

Tom Seemeyer II (a.k.a. El Cheapo) said...

Thanks, Tim. It's awesome how much help we have received from people that are not directly involved in the physical build of the MLAS prototypes. The information we have gotten from you as well as the people you have put us in contact with has been invaluable. We probably could not have gotten the precise scale measurements without your help and Gordon from www.excelsiorrocketry.com (shameless plug).

Tim Wilson said...

Glad to help! BTW, Rich McKee's query to Chris Rink (LaRC) was ultimately forwarded to me. So let me know if there's something we can do for you. And again, good luck!