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Mercury ring engine balancer

seagull

Well Known Member
Has anyone used one of these? What were your thoughts?
The company is Sun-Tech, the person answering the phone talked like he was the owner but when I asked if after putting it on my plane would I be able to read .00ips at the propeller he said no. I think the principal works but would like to hear from actual users. Apparently they make a unit for the propeller and another for the engine since our 912 with gearbox have 2 different RPMs.
 
Has anyone used one of these? What were your thoughts?
The company is Sun-Tech, the person answering the phone talked like he was the owner but when I asked if after putting it on my plane would I be able to read .00ips at the propeller he said no. I think the principal works but would like to hear from actual users. Apparently they make a unit for the propeller and another for the engine since our 912 with gearbox have 2 different RPMs.

I'm curious as to where one might install one, other than the prop hub...
 
He said one fits between the prop drive plate and the spinner backplate. The other one for the engine fits in the stator bolt at the rear of the engine.
 
Has anyone used one of these? What were your thoughts?

Yup, I tried one on my iS - between the prop flange and spinner backplate. Absolutely zero change in vibration. Certainly there was some variation introduced when the blades were repitched (2-blade prop) after installing the balancer, but no change. I spoke with the owner, who is the developer of the device, and he essentially said I couldn’t be seeing no change. Now my initial vibration was out around 0.8 ips, so really bad. Had to add 37 g to the spinner backplate on an 8” diameter. I suspect there just isn’t enough mercury in the device to make that much of an improvement. Maybe someone with a better starting point might see an improvement, but none for me. He agreed to take it back - purchased through Spruce.
 
Good info Bob,

I asked the guy on the phone, assume owner, what the weight of the mercury was and he hedged the answer saying people were trying to copy his idea.

I wanted to know because he said I had to remove the dynamic fixed weight that I was currently using (14 grams on a 9.5" circle) then put on his balance master that had a 7" circle. That meant the BM had to have at least 19 gm to do the same work. He claimed it did not need to be that heavy because it was mercury and would spread out and was the lowest friction known, etc.

I felt I was being talked to (sold) like I was a soccer mom, no offense to the soccer moms.

In the end he told me not to buy it even though he didn't say those words.

I can see that the BM might save the time involved of a dynamic balance, and get a close balance but I don't see this technology being used in cars, and such even though the concept has been around for a very long time.
 
Do you have a link to a website showing this product?

In the past, there has been a lot of confusion over devices designed to dampen engine firing pulses, but people mistakenly thought they balanced the engine/prop. Those are very different concepts, IMO.
 
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