Volvo penta folding propeller repair

[foboss]

Hi guys!
I collect information on the repair of folding Volvo propellers.
I have fused new teeth and now the propeller is folding correctly. I weighed the blades and found that they have different weights. This is bad?
Also, the blades have a slight play on the axles. This is normal?

[foboss]

It was

Has become

[DougR]

It is difficult, if not impossible to say that the difference in weight means much. What is important is whether the prop is in balance, and the prop can be in balance even if the blade weight is different.

For example, let's say you have a two blade prop with perfect balance. Now you place .1 kg at the tip of one blade and .2 kg half way out to the tip on the other blade. The prop will still be in balance, but the blade weight will be different.

So, what you need to do is to take the prop to a good prop shop and have it balanced, or put it on the boat and see how it feels.

As far as the play on the pins.......unless it's a brand new prop there will always be some play on the pins and if it's slight I wouldn't get too excited about it.

DougR

[foboss]

Thank you man!
Prop is not new

I will try to check the balance in the car service and report the result.

Alex

[foboss]

the blades have play.
is this permissible?
https://youtu.be/7jCZ_C-B27o

[fstbttms]

If the color in the original pic is accurate, that prop looks extremely dezincified, further evidenced by the broken teeth on the blade. My guess is that the repair will fail soon and/or other teeth will break.

[foboss]

The color is not right! This is the color after cleaning with vinegar and salt and after heating to surf the teeth.
I will do the balancing, polish and show.

the surface of the blades is in good condition and not damaged.

[foboss]

another question, on which side of the blade to remove metal for balancing?

[foboss]

Balance Check Video

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1 blade position

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Swap blades

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So, the result is an imbalance in the direction of the blade with a larger weight, and when the blades are rearranged in places, the magnitude of the imbalance changes.

The experiment is not entirely clean, since the machine shaft itself had some imbalance and, due to the peculiarities of the propeller design, it was possible to fix it only at the very end - to the place of maximum shaft runout.

I plan to continue the experiment, namely, to replace the shaft with a shorter one (an M16 bolt with a length of 140 mm is suitable) and make an additional cone on this shaft.

[foboss]

Subtotal:

I bought a screw DIN 912 16x120, high strength 12.9. The length can be selected according to the length of the hub and the type of balancing machine.

This model is made in Germany, therefore more or less even.

Cone - made a turner for the diameter of the screw, dimensions:

The diameter of the bolt hole is 16mm.

D \ d: 32mm \ 20mm

Length: 28mm

Dimensions are chosen to go into the hub of the S-Drive.

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The result in the video.



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The result is intermediate, as I plan to clean everything up to the end, polish the blades, tighten the anodes and finally check.