Prop Balance Question..

[rob999]

Having had my first flight on my new sparkly out of the box Zenith Moster (under and Ozone Roadster) I have to declare I love it. The 'no electric start or clutch' issue has not reared its head just yet, I guess its just approaching things with a spinning prop in mind.

Leading me to my question about the spinning prop.. As the football was on and I dislike it, I was in the garage stroking my new baby. I wondered if the prop was balanced, surely it must be. So off it came and into the kitchen we went. Its a Parajet, 130cm carbonfibre twin bladed.

Please be kind, the following is mostly based on balancing RC Helo rotors !!

I weighed each blade and found a weight difference of 5gms. Insulation tape to the value of 5gms wrapped close to the hub thus bringing the weight to 564g per blade.

Fitted both halves together, a makeshift thin axle placed through the hub and supported, ensuring 90 degrees between the prop and the axle. Two wraps of tape at the end of the heavier blade to bring the balance back and corresponding tape applied to the opposing hub area to maintain the weight of each blade.

It all now seems to balance out ok and each blade weighs the same to the nearest gram.

Have I done it correctly ?? Or is 5g out totally acceptable and rip all of the tape off ?? I have probably added max 1g to the blade tip to ensure balance, literally just two wraps.

Any comments ??? Or Advice ???

[ptwizz]

I can see nothing wrong with your method for static balance.

Also worth looking at is tracking (you'll probably recognise this from RC helicopters).

With the prop fitted to the engine and the plug cap removed, turn the prop by hand, noting the distance from each tip relative to the frame in the for-aft direction. If the prop wobbles in this plane, the engine mounts will be unduly stressed.

To correct wobble, cut semi-circular paper shims to fit between the prop and the face of the prop driver. Once you have the right thickness of shims, they can be glued to the appropriate side of the prop.