Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: benjaml1 on February 23, 2010, 10:46:32 pm
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Hull type: Wide beam ( Orion moldings "Fifie") Open working boat 1/6 scale
Engine: Stuart Turner "Sun" 3/4" x3/4" single acting twin. Max RPM guestimation 2000rpm
Displacement: Approx 50 pounds
Any recommendations on propeller size/pitch ? I want a scale presence on the water...
Ta in advance... :-))
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I don't know, but did you try asking the people at Propshop?
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I don't know, but did you try asking the people at Propshop?
Thank you for that, I am going to but thought I would ask the experienced forum first.... :-))
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Looks like the experienced forum is either on vacation or clueless :embarrassed:
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Looks like the experienced forum is either on vacation or clueless :embarrassed:
116 views & one reply... ;)
Naaa.... This is a tough one. I can work out the pitch as the boat is a displacement hull with a lot of drag requiring a higher slip in the calculation. Diameter ? Well I could go for scale of 1/6th but just wondering what everyone else was using really... 3 blade, 4 blade etc...
Thank you kno3.... :-))
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If it's a slow revving engine, then use a prop with 4 blades. I'd go first with what looks good to you, evaluate the performance and then change the prop if needed.
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Thanks for that... :-))
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I remember someone saying one inch of prop for every 1/4" of cylinder dia. I normally ether fit a prop to the scale of the boat or the largest one that will fit.
Regards,
Gerald.
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I remember someone saying one inch of prop for every 1/4" of cylinder dia. I normally ether fit a prop to the scale of the boat or the largest one that will fit.
Regards,
Gerald.
That would make sense, thanks for that Gerald... :-))
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Benj,
I have an old MB article on sizing of steam plant props that may help. PM me with your email address and I will forward it.
Barry M
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Thanks Barry, PM on the way... :-))
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On mine I used a 4" dia x 10pitch 2 bladed, but then I was running a high speed flash plant. My second had a 3" dia x 6" pitch 3 bladed which pushed a 5ft long boat along at more than a brisk walking place. The prop was similar to the Stuarts props they did years ago. Sadly I can't remember where I got it from (it was more than a couple of years ago :embarrassed:) You could try something around that size to start off with, and as kno3 has suggested try a couple of others (try with a few cheap plastic ones--that always helps the budget O0)
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Good advice on the plastic ones, never thought of that... :-))