Hartzell Propeller balance

[JimB]

Just out of curiosity where would the dynamic balance weights be installed on an IO-360-A1A (M20F/HC-C2Y)? I have exhausted my Google searching capabilities but from my research they could be mounted on the front of starter ring gear or the inside of the lip on the bulkhead with a counter sunk screw. Where is the right location? It sounds like the ring gear may not be able to be used because the spinner bulkhead also mounts there. I don't see any on mine and I am curious if it has ever been dynamically balanced. 

 

Edited March 19, 2020 by JimB

[carusoam]

Let’s ask an The MS prop guru...   @Cody Stallings (Question about balance weights)

Best regards,

-a-

 

[Cody Stallings]

Awwww Yes!!!!...... A very sticky Subject.

The Short Answer is Put weights on the hub.

But that just how I do it.

There are times I will install weights in the Spinner ring gear Backing plate if need to make a tiny adjustment.

Also have to say my Repairstation only uses Chadwick-Helmuth Balance an Vibration equipment. So we work out of the 9511-2 Manuel, an That Manuel states very clearly nothing is to be bolted to the starter ring gear of a Lycoming engine.

 

I can’t speak for Access Equipment or DynaVibes having never cracked the Manuel on one.

They May say otherwise.

But a good rule of thumb when balancing a propeller is to stay as close to the propeller as possible. The further you get from the propeller with solution weights,the less affect it has on the balance issue 

[JimB]

6 hours ago, Cody Stallings said:

Awwww Yes!!!!...... A very sticky Subject.

The Short Answer is Put weights on the hub.

But that just how I do it.

There are times I will install weights in the Spinner ring gear Backing plate if need to make a tiny adjustment.

Also have to say my Repairstation only uses Chadwick-Helmuth Balance an Vibration equipment. So we work out of the 9511-2 Manuel, an That Manuel states very clearly nothing is to be bolted to the starter ring gear of a Lycoming engine.

 

I can’t speak for Access Equipment or DynaVibes having never cracked the Manuel on one.

They May say otherwise.

But a good rule of thumb when balancing a propeller is to stay as close to the propeller as possible. The further you get from the propeller with solution weights,the less affect it has on the balance issue 

Thanks Cody,

When I was unable to find anything on this, I thought it might be a "sticky subject". I have access to some new ACES equipment and thought I might check/balance my prop. The last props I balanced were turboprops back in the early 90s using the old ring-of-lights balancer and this new equipment looks really easy to use. But I was looking to see if there were any existing weights and didn't find any. Then I started looking at where I can mount some for balancing and didn't see any pre-existing holes for that. I was really hoping to not have to drill holes to mount weights but the ACES manual has the same sort of restriction "On any engine that has the spinner bulkhead attached directly to the starter ring gear, do not attach weights to the bolts that retain the spinner bulkhead to the starter ring gear. This installation requires that the weights be installed on the inner portion of the spinner bulkhead."

It's been my experience that beyond the obvious pilot/passenger comfort, a smooth well balanced propeller is better for everything. Even small vibrations and balance issues that might not bother the pilot can wreak all sorts of havoc with engine/airframe brackets, electrical connections, accessories, etc. We solved a lot of issues on the turboprops just by keeping the props well balanced. It just makes sense and it really isn't expensive to have your prop balanced/checked.