Prop calculation

[Wedger]

Anyone know where I can get a calculation for duoprops please.

 

Just gone to a 290 DP-e but can't find a calculation.

 

[oysterboats]

have you tried propcalc web site

[Wedger]

Do you have the address for the prpcalc site please?

 

I've not got DP on the Castle Marine bit i've downloaded.

[Rob]

 

Trev,

 

If you calculate the standard 3 blade prop you would neeed, could the DuoProp dealer advise you of the "equivilant" Duo?

 

I have no idea what I am talking about, but, it is good to talk!!

 

R

[duncan]

Do you have the address for the prpcalc site please?

 

I've not got DP on the Castle Marine bit i've downloaded.

none of them do Terry

 

you have the same engine and revs available, so you only really need the relative gear ratios of the leg you took off and the one you are putting on to give you a relative starting point.

 

and that should probably be the same pitch as the one you are taking off if the ratios are the same

 

DP doesn't really change the underlying formulae but you will get less slip at outset and more efficency carried through the range - this can mean that you need to go lower if the engine can't get to turbo revs before the hull speed becomes a limit (previously it would simply have slipped the prop with the avaiable power but now it may not be able to) - or it may not.

 

from there it's fine tuning on the various choices you have available in that range for which a calculator really won't help!

[Wedger]

 

I need a rest

 

Thanks dunc.

 

 

 

 

[Coddy]

Trev you have a PM

 

Coddy

[Wedger]

Thanks Dave

 

[oysterboats]

if propcalc no good try mike bellamy at lancing marine he is a very knowlegeable guy and may be able to help

[Wedger]

thank you chaps.