Play in Flex-O-Fold blades-hub after 2 400 hours, normal?

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skippeer

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I am planning to procure a new Flex-O-Fold propeller sitting on my VP D2-55 with a shaft after 2 400 hours.

I am pleased with the speed so I will order the same 3 blade prop again.

How many hours could be expected?
 
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The play shown in your video doesn't look excessive. Given the cost of a replacement 3-bladed Flex-o-Fold, I'd first have a look at the pivot pins and perhaps just replace them. Spares should be readily available.
 
Do you know if it is in the pivot pins or the blade? Talk to Darglow who will check it over for you and refurbish if necessary.

Sorry, just seen you are not in UK. Speak to FleoFold direct or their distributor in Sweden.
 
The challenge is that the boat is in France and I am 2000 km north.
The good news from you is that I might can have it repaired.
I will ask the manufacture in DK for second opinion.

Maybe I buy a new and bring the old to a prop specialist to be used as future spare part or to sell as used.

thx for your input
 
You can replace the pins and blades for about half the price of a new prop. Unlikely there is any wear in the hub or the gears.
 
I have been in contact with Flex-O-Fold manufacture in Denmark regarding:
  • can it be repaired
  • which size of a new FOF 3 blade prop for shaft mount
  • prop puller
  • cons and pros with new calculated size compared with existing
Email response only contained calculated size and price:
  • 18x14-3R
  • €2,655.00 incl VAT and delivery
My original prop size is 20-13-3R and my question about it's condition did I not got any answer on from the sales person @ FOF.

Called a local prop mechanic company for guidance after sharing the YT video.
His reply was that prop can not be repaired but can be used until it stop to fold out the 3 blades.
We discussed theoretical design vs practical test so my plan is to use the old prop another season and a calm day (no wind/no waves) run speed test with different RPMs and write down the speed .

After this season will I use the speed test protocol in procurement discussion with prop company.
 
If you have not already done so I stongly suggest you talk to Darglow engineering. They are agents for Flexofold and also service propellers. I suspect they will be able to ream and bush your prop taking it back to is origonal spec. They can do this for more complex feathering max props as had been done on my boat.
Home
 
When I lifted our boat to the hard in October 2024 did I notice that the blades have damaged each other probably due to play in the "cogs/teeths".
Have removed the hub and will bring it to a propeller shop to get help to verify that it is ISO 35 mm shaft before ordering a new complete prop (blades + hub).
Hub-blade play after season 2024

Here is the play on another FOF
 
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Unless you are setting off on a round the world trip I would run the prop as is for another season. These props are really robust.
Next time you take her out of the water take the prop to a precision machining company and get them to make new pins slightly over size and open the blade holes slightly if necessary. It should cost a fraction of the price of a new prop. They will need to adjust the size of the grooves in the pin that secures the pin in place.
That’s what I would do but if you have plenty of money then a new unit is easier
 
I removed the propeller including the hub and took it with me on the flight from Spain back to Sweden just before Christmas.

The plan is to show the propeller for a specialist and get a judgement. When I on the phone 2 years ago asked for advice
he suggested to avoid rpms making noice.

After 2 800 engine hours I am not surprised that the folding prop need TLC or replacement.
When sailing 3 000 km away from home port I need a safe engine & prop so a new one is ok.

WOT test with original prop (20x13-3R) shows 2 450 rpm.
recommendation from Danish manufactorer is to buy a 18x14-3R.
One spin-off could be +300 rpm which is better for our boat, WOT 2700 RPM would be perfect for a blue water displacement boat
(max rpm according to VP spec is 3 000 rpm).
 
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Sound advice. The current prop size is too large and the suggested reduction will allow you to access near maximum power if needed. Hopefully you will need just the new blades rather than a complete propeller.
 
Last week did I take my old FOF 20x13-3R to the prop shop.
The old blades are damaged.
He verified the hub status by mounting new blades with old pivot pins, the hub was okej.

Today did the shop called back, prop calculation => 19,4 x 13, so my original prop size was in theory the right for engine and hull but WOT at sea trial gave around 2 450 RPM.

20x13-3R => 19x13-3R adds on 200-250 RPM at WOT
20x13-3R => 19x12-3R adds on 400-500 RPM at WOT

A sailing friend working at Penta recommend me as blue water sailor to aim for 2700 RPM (10% lower than engine spec).

Plan is to go for new blades 19x13 and reuse the hub.
Waiting on a price quote.
 
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Does it matter if the new prop will be

19 x 13 - 3R (proposal from local prop shop)
or
18 x 14 - 3R (proposal from FOF vendor)

Is the larger diameter providing more power / more efficient?
 
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They are effectively the same "size" if you assume 1:1 ratio between pitch and diameter (rule of thumb not totally accurate), but the other rule of thumb is that larger diameter is to be preferred, particularly if there is something that interferes with water flow like a long keel or skeg as you get more blade area out in clearer water. Tip clearance to hull can also be a constraint on diameter, but probably not in your case as you already had a 20" diameter.

There won't be much difference between the two sizes in terms of the load on the engine and either will give you the +/- 300rpm change in WOT rpm. On balance I think i would go for the 19" Either will allow you to access more of the engine's power in demanding conditions and probably make low speed work better because of the reduction in thrust at low rpm that makes response more progressive.
 
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