prop balancing

[TGio]

Steve,
Well done! Did you ream the hole you drilled in the spinner backing plate? Keep a real good eye on it. It will crack if the hole has a stress riser on it.

[Slyfox]

Actually the spinner cap, fiberglass, was the area that I put the weights to. But yes, I cleaned everything up real nice.

[Caballo]

For years my wooden prop was stored in the parallel position, but is has been stored in the upright position for a few years also.

For the Mod.III with a 582 engine, is there a prop that is less prone to deterioration and vibration over other types and brands?

[SkyPirate]

it's not good to store wood props in the upright position ,..although some might disagree,..you might need to have it balanced,..depends on your humidity,..if the place it was stored was hot,..etc,..if you can always store a wood prop on a flat surface spinner side up.

Chase

[Caballo]

Thanks Chase. It is still in the box it was shipped in but I have placed it in the horizontal position for now. I will take it to Las Cruces and have it balanced before I install it later this year.

[akarmy]

Hey Steve, Can you give a bit more detail on how you attached the weights? Are you going into the back plate of the spinner with your rivets, or into the side flange of the back plate? Do you have to remove the spinner cap to install the weights? Etc? Any pictures?

Me and a buddy just got the Dynavibe and are going to balance the Kitfox and his RV.

[Slyfox]

On the kitfox I put the weights to the spinner. My spinner is the bigger fiberglass 9" spinner. I put them on the rear of the spinner with the weights to the inside. The rivets are stainless CS4-4 I think round head. The weights are the flat sticky on the back side, with a strip that is in 1/4 pieces. I got mine from Motion auto parts for about 30 dollars. I found that if you take the weight and smack it with a hammer and flatten it out the rivet works real nice and only one revit. On the RV I left the spinner on and balanced and put the weight right on the outer back side of the back plate for the spinner. After all was balanced I drilled a hole in the weight to the back plate with an angle drill and put a poppy in to hold it. worked great and got both down to near 0 on the ISP. And it was quick. Make sure and take the time to put the degrees on the flywheel (every 10 degrees) for the rv and the hub on the kitfox. Also make sure the degrees looking at the prob from the front goes in the direction of the prop, which would be counterclockwise.

Oh and the bracket I made works on both engines. The rv I work off the front bolt for the case half on top. The kitfox 912 I work off the top bolt hole on the left side of the gear case. I also leave the tape on the prop, the RV I can see when flying the kitfox I don't see. I'll be checking the balance every 100hrs and to do it is real quick, so no problem.

[Dorsal]

Steve, if you think of it please post again after the 100 hours, curious if you see much change.

[akarmy]

Ok on the Rv we got it to 0.01 ips using bolts and washers in the ring gear. Worked great. On the kitfox I can't seem to get it below 0.15 no matter what I try. I have the same mounting locations as you. I have been sticking the weight on the inside of the backplate flange so the centrifical force slings them against the fiberglass.

My initial no weight ips is 0.25

about how much weight are you ending up using? Also, are you able to balance with one weight location, or multiple?

For reference, I'm running an ivo medium 3 blade.

[akarmy]

Thanks Steve for the idea to pre-index the prop hub. That really makes it clear what you are doing and saves a ton of time.



After stepping back and starting over fresh on another day, I was able to quite quickly get it down from a starting point of 0.35 to 0.01 as a finished balance.

more pictures are on my site if you want to see the process.

http://flying.karmy.com/?p=344