Prop Balance...almost

455 Bravo Uniform

455 Bravo Uniform

Final Approach
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Aug 18, 2015
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455 Bravo Uniform
1st run 0.41 ips
2nd 0.30
3rd 0.22
4th 0.16
5th 0.06.
Had to add 40.5 grams at the spinner to get to the final solution.

Unfortunately, calculating the amount needed on the spinner bulkhead (shorter arm/radius), which I think came out to 58 grams, means too high a moment at the spinner bulkhead (not recommended per the ACES manual). No flywheel.

A&P is going to call a prop shop tomorrow.

How have some of you dealt with this much weight needed on a spinner bulkhead? Divide and spread weights over 2 or 3 stations? Or remove and send prop to a shop?

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455 Bravo Uniform said:
58 grams, means too high a moment at the spinner bulkhead (
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Moment? If mean too much weight at one point okay. Split weight and mount at two locations using different arm/moment calculations and reverify ips.

But there can be several other issues that can cause that much weight to be used. Is the prop in track? Spinner hardware all same type/size? Reindex spinner to different location if possible. But hard to tell through pics.
 
Bell206 said:
Moment? If mean too much weight at one point okay. Split weight and mount at two locations using different arm/moment calculations and reverify ips.

But there can be several other issues that can cause that much weight to be used. Is the prop in track? Spinner hardware all same type/size? Reindex spinner to different location if possible. But hard to tell through pics.
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Yeah, too much weight at one point.
 
I agree that's way too much weight, and will eventually tear out the rear spinner bulkhead. Is the weight in line with one blade? or is it 90 degrees to the blade axis (assuming 2 blades). If it is 90 degrees and a 2 blade prop, the prop is probably out of edge alignment (bent like a boomerang) and may have to be scrapped. Talk to a prop shop. Not good.
 
Thanks guys. The prop shop said that 0.4 ips should not require that much weight. They are having us do two runs, with the sensor in the front once and the rear next.

Looking back, we think the cowl might have been coming close to the sensor and it might not have been completely vertical. We’ll try again.

Good thing is I’m getting my hot start technique perfected.
 
nrpetersen said:
I agree that's way too much weight, and will eventually tear out the rear spinner bulkhead. Is the weight in line with one blade? or is it 90 degrees to the blade axis (assuming 2 blades). If it is 90 degrees and a 2 blade prop, the prop is probably out of edge alignment (bent like a boomerang) and may have to be scrapped. Talk to a prop shop. Not good.
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2 blade, yes. Not 90 degrees, more like 65-70.
 
Timbeck2 said:
I thought the weights went on the ring, not the spinner.
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That's what we do on the Lycomings you and I have.
From the pictures this looks like a Continental O-470 powered Katmai STOL 182, so don't think it has the same starter-ring/flywheel arrangement on the front of the engine we have with our Lycomings?
 
GRG55 said:
That's what we do on the Lycomings you and I have.
From the pictures this looks like a Continental O-470 powered Katmai STOL 182, so don't think it has the same starter-ring/flywheel arrangement on the front of the engine we have with our Lycomings?
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Aha....thanks.
 
I've have experience with the ACEs probalancer sport and most planes with higher IPS numbers need to split the weights. The ACEs has a default question to split weights when it sees a larger number of grams needed. Lycomings are easy to do as they have a flywheel with holes every 30 degrees. Continentals are a bit more difficult to place weights. If minimal weight needed a longer screw can replace a spinner screw with washers added on the inside of the spinner and capped with a nyloc (you have to subtract the weight of the original screw). The pic you show presents a problem. Even though you may have hit on the right amount of weight for a good reading on the outside of the spinner, as you move that weight inboard to the bulkhead you are reducing the effectiveness and would need more weight to get the same reading. You'd be better off using the split feature on the ACEs and trying to keep the weights on the inside of the spinner.
 
When I had my prop balanced the weights were on the flywheel. Why is yours on the spinner?
 
GRG55 said:
That's what we do on the Lycomings you and I have.
From the pictures this looks like a Continental O-470 powered Katmai STOL 182, so don't think it has the same starter-ring/flywheel arrangement on the front of the engine we have with our Lycomings?
Click to expand...

Yes, Conti. IO-470. Peterson 260SE.
 
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