Sometimes with rockets WITHOUT an engine hook I have to resort to the pliers or the dowel technique when I friction fit motors (wrap a bit of tape sound them to increase the outside diameter enough they fit tightly enough to not "self-eject".). Always a bit of a challenge to put enough in to keep the motor in during flight but be able to relatively easily remove it at the end. (tip- always remove spent engines before putting them in the car- either in a sealed bag if you bring them home or toss them in an appropriate trash can. Spent engines in the car will surprising quickly smell up the interior.)
Originally Posted by xwingfighter10
Back to topic-- your rocket looks great, congrats on a nice build. Usually with engine hook rockets I have found the engine is relatively loose in the mount (mount is usually 20 mm diameter body tube, engine is 18 mm.). I am wondering if during your build "something" swelled up narrowing the internal diameter or your tube. You may consider wrapping a piece of intermediate grit sand paper (say 220 or so) around a dowel or stick that easily passes into the motor mount tube (something around the diameter of a 13 mm mini-engine would be perfect) and GENTLY sanding the INSIDE of the tube until you get a good but not so tight fit. But if you can successfully shove the motor out from the front with a stick or dowel or gentle work with pliers works to get engine out without injury to the rocket, probably should just leave it alone. Try a flight or two as is. Too TIGHT a motor is not a flight risk.
Also JR's idea about removing the engine immediately after flight in my experience is a good one. I have GENERALLY found on my friction fit motors that an engine that was quite "tight" at launch is relatively loose immediately at landing.
Good luck and looking forward to your launch report and pics.
Last edited by BABAR; 15th June 2012 at 02:23 PM.
Reason: Stupid spell correct!
It is amazing what you can do when you don't have a choice.
Smart people learn from their mistakes.
REALLY SMART PEOPLE learn from OTHERS' mistakes.