Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: ghost123uk on October 02, 2010, 12:40:29 pm

Title: Anyone know of a cross refence chart for prop sizes ?
Post by: ghost123uk on October 02, 2010, 12:40:29 pm

I used to use Mocom alloy props on my CMB67 powered multi. (now sadly sold 2 years ago)
A 2024 or (2023 for rougher water) was normal.

Now, my new (to me) Fairey Swordfish has been tested with various Plastic (black) props and a 52.5 "X" pitch seems about right.

Question = what would that be in Mocom numbers ?

I bet there is a comparison table somewhere, but I cannot find one !
(note = I have seen the suggested prop by engine size chart that quotes Mocom type numbers).

There is a Mocom size chart at PMB ( here = http://www.prestwich.ndirect.co.uk/mocompropellers.htm )

Title: Re: Anyone know of a cross refence chart for prop sizes ?
Post by: ghost123uk on October 02, 2010, 02:20:20 pm

Quote from: ghost123uk on October 02, 2010, 12:40:29 pm

There is a Mocom size chart at PMB ( here = http://www.prestwich.ndirect.co.uk/mocompropellers.htm )

I just found this chart on PMB for plastic prop specs. (here = http://www.prestwich.ndirect.co.uk/plastic_props.htm )

Trouble is it only gives specs for "X" pitch  :((

Title: Re: Anyone know of a cross refence chart for prop sizes ?
Post by: w3bby on October 02, 2010, 09:43:06 pm

I believe you have answered you own question, however:

The 52,5X that you are using has a pitch of 73,5mm according to the chart so X in this case gives you a diameter:pitch ratio of 1,4 (52,5 x 1,4=73,5). The mocom nearest to that from the mocom chart would be the 1748M, 52mm diameter x 74mm pitch. I have never been able to work out what the mocom numbers refer to.. At least the newer numbers, 5780 and 5983, refer to diameter and pitch in mm.