View Single Post
  #2  
Old 03-27-2019, 11:18 AM
Doug Sams's Avatar
Doug Sams Doug Sams is offline
Old Far...er...Rocketeer
 
Join Date: Mar 2005
Location: Plano, TX resident since 1998.
Posts: 3,965
Default

Quote:
Originally Posted by Newbomb Turk
A10-0T, A10-0T, A3-4T
Bummer about your wreck. Is the Mini a BT-20 based kit? I've built and flown a few small 3-stagers using that motor combo, or maybe a ¼A or ½A in the upper stage. No doubt, the big thrust spike should be sufficient to get the stack moving off the rod.

The two thoughts I have on this are either nozzle erosion/flaking, or wind catching it during the long tail of the thrust curve.

Can you inspect the 1st stage motor's nozzle for any signs of it being asymmetric?

The long tail on the thrust curve presents an opportunity for wind to affect the flight, altho the more I think about it, the less I worry about. That is, if the thrust spike got it moving off the rod with decent speed, then, even with the long, low thrust tail, it shouldn't lose any speed, so it should still be tolerant of a cross wind that could impart weather cocking.

If it looked like it came off the rod with decent speed, then it's not the low thrust tail.

Besides these two things, the other thought is rod binding. How's your launch lug? Is it long enough not to bind? Was the rod clean? Did you wipe it down before loading the rocket? Again, if it came off the rod with good speed, this is not part of the problem.

Anyway, those are my thoughts. Like you, I am (or was) an avid stager - there's nothing like the rush I get when the next stage lights


Doug


.
__________________
YORF member #11
Reply With Quote