Originally posted by Ragz
Ok..now my roo gears are sorted out...what abt the engine thrust angle? A friend of mine has put some shims at the BACK of his p120, effectively pointing the engine downwards (tail cone UP, so effectively giving the plane a down thrust). He says this setup makes the plane fly well. He hold full up elevator from the beginning and the roo rotates comfortably.
I remember that there was a discussion on RCU some time ago...where someone suggested to shim the engine from the FRONT...so as to point it slightly upwards (giving it an upthrust). The argument there, I believe was, to compesate for the higher engine thrust line vis a vis the roo's itself.
Are there different setups for different flight characteristics? Advanced vs. novice? I am confused.
Thanks in advance.
Anurag
PS: Enigne is a P120
Anurag,
I have no idea why someone would suggest shimming the front of the engine UP relative to the back. That would make the problems of a high engine thrust line with the engine in back WORSE. With the engine in back, shimming the FRONT of the engine UP is in fact, DOWNTRUST - since it tends to force the nose DOWN. What you want is the engine thrust line to point as close as possible to the line going through the aircraft's center of pressure. Since the engine on the Roo is elevated and in back, pointing the engine DOWN in the front makes it point closer to the center of pressure, which is probably somewhere near the CG line at about mid-fuse in height.
I shimmed my engine UP in BACK as suggested by the instructions to start. I have since removed most of the washers and I notice that it takes a bit more takeoff run to rotate, but that is all I can tell as far as a difference. I have no doubt though that if you shim the engine UP in FRONT, you will make it into a somewhat hard to control RC turbine powered truck...
Bob