coralcape

My Feedback: (4)

I am getting a lot of vibration on a recently converted featherlite (say's 21cc) Have it on an goldberg ultimate. I removed the ignition and flywheel and run it on glow (3/4 straight methanol 1/4 mustang 10%) Runs good but so much shaking at any throttle. Used the cut down flywheel as base for prop adapter, so my added adapter lentht is centered and balanced ok. Prop is balanced ok. Anyone do any balancing to piston, and if so any guidelines? Other suggestions? Thanks, red

davewallace

My Feedback: (29)

Red,
The counter balance has to balance one half of the weight of the piston,rings,con rod and wrist pin etc. It is easier to do on a your engine, because you can weigh the piston and rod assembly sepparatly with a gram scale. Use a prop balancer, such as Hi-Point or Topflite after removing the crank shaft from the case. Attach a weight to the crank pin equal to 1/2 the weight of the piston assembly as stated above. Carefully remove material from the counter weight until it balances. If the crank pin side is the heavy side, you will either have to remove some material from the piston or rod or add weight to the counter weight. This is more difficult. Drill holes in the counter weight and press in a heavy metal such as tunstun or lead. All holes for adding weight should be paraell to the shaft. Since the cutdown flywheel is keyed, weight can be added to it, being careful to not weaken it. Let us know how it works out. Good luck.

Dave

coralcape

My Feedback: (4)

Thanks Dave, makes complete sense. I will have to get a gram scale. I like this little engine, very light (2lbs 15oz with muffler, prop and mount) Has good power, but really shakes the plane. It may be a while, but I'll get er done. red