Balancing RV-12iS - Where did you mount accelerometer, optic, cowl on or off?

[jackking123]

I am going to rent a ACES 1015 Sport.

I gather you have to make a bracket, no big deal,

• Did you mount accelerometer on gearbox housing?
• Did you have cowl on or off?
• Where did you put the optical sensor? Tape on cowl?'
• Drill hole in backing plate at OD of spinner backplate?
• Used #10 screw, nylon lock nut, washers?
• How much weight did you add?
• What inches per second (IPS) before and after balance?

ANY TIPS Tricks, Lessons, Learned,

 

[seagull]

• Mount accelerometer to the top / left of the gearbox as close (safe) to the propeller plane as possible for the best readings. There is a threaded hole you can use at that location. The wire needs a bit of freedom so it won't transmit vibration back into the accelerometer.
• Cowl top off, bottom on or off.
• Optical sensor to the rear of the gearbox on "L" bracket. Tape on cowl will work but means the cowl will have to be on and that causes problems mounting accelerometer.
• Initial "test" weights are added to spinner screws. This gives you the correct "clock" position and amount for final weights. Recalculate the final weight amount due to smaller radius when mounted to spinner back plate. Use #10 screw / washers / nylon lock nut. Amount of weight added is based on the imbalance.
• If initial IPS is over 1.20 IPS there are other issues balancing can't fix.
• Typical on Sensenich 2 blade on 912 is .08 - .35 IPS. Finished balance should be .06 or below.

In my experience most pilots won't notice improvements below .12 IPS, but strive for lower, your airplane will thank you.

 

[rv12is]

Here are a couple of recent threads about this:
https://www.vansairforce.net/threads/dynavibe-bracket-photos-wanted.243060/
https://www.vansairforce.net/threads/dynamic-propeller-balancing-using-the-dynavibe-classic.242699/

In particular this post from N8DAV8R has good pictures of mounting brackets.
https://vansairforce.net/threads/dynavibe-bracket-photos-wanted.243060/post-1927565

This post from Tony_T has good pictures showing how to mount the temporary and final weights.
https://vansairforce.net/threads/dy...sing-the-dynavibe-classic.242699/post-1923992

And attached to this post from Bob Y is the Application Note "DynaVibe Procedure for Rotax 912 PropellerBalancing". While you may not be using a DynaVibe, most of it should still be applicable to other systems.
https://vansairforce.net/threads/dynamic-balancing-rotax-912.220220/post-1711876

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Before balancing I got 0.2 IPS. Test weights (on two spinner screws) of 1.3 grams and 6.7 grams, brought it down to 0.05 IPS. Final value after adding ~10 grams to a newly drilled hole in spinner backplate was 0.06 IPS.

 

[jackking123]

rv12is:
I missed that thread, Doha... Thank you. That is all I need for now. I got a quote for $350 from local guy who did not have brackets or rent for $185, Seems to be straight forward. Save $165.