Changing Propellor from 2 to 3 blade

[Stroma Pilot]

Can anyone advise me what size 3 bladed prop would be compatable with a perkins 80hp coupled to a 2 to 1 reduction hurth zf gearbox on the Nic 38 please? I have a job sheet/invoice for changing the twist on the 2 blade from 18x 13 to 18 x 16 inches – does anyone know if that is compatable with the power plant and g/box as above?

[Moderator]

Did you read the earlier posting on this topic? (Click Here to find it)

Did you mean Perkins 50 HP, as in a 4-108? We put on an Axiom prop and are quite happy with it. We have the Perkins 4-108 with Thamesway TMP-12000. You can read about our Axiom prop experiences in the other posting.

Cheers –
Marilyn

[Van]

One finding in the earlier thread was that an 18 inch diameter prop is really close to the deadwood and causes a lot of vibration and noise. We had a similar problem on Rainshadow, but in this case it was a 16″ prop too far forward. For an exhaustive (exhausting) analysis of the prop question, see our blog at http://svrainshadow.com/?p=719. We are quite happy with the fixed three blade prop we got from Axiom. It’s 15.25″ diameter. However, because of the smaller blade area it does suffer from cavitation above 2500 RPM. In hindsight, I might have tried a 16″ diameter prop to get a bit more thrust and reduced cavitation, at the expense of perhaps a little more noise from the shock waves on the deadwood.

Good luck,
Van

If you are so inclined, the book Propellor Handbook by David Gerr is very good.

[Stroma Pilot]

Thaks all.
The engine is a Perkins M80T Prima with 2.74 : 1 reduction Hurth ZF box (not 2-1 as prev posted. These 2.0L Turbo diesel engines were used in Maestro & Montego Cars and Sherpa Vans.
If anyone out there has a wiring diagram for the M80T I would appreciate a copy
Thanks
William

[Author]

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