Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: Popeye on March 25, 2012, 11:15:59 pm

Title: 3 or 4 bladed prop.
Post by: Popeye on March 25, 2012, 11:15:59 pm
Given the same diameter, which prop is better suited to an ungeared '540' low drain motor where torque is more important than speed?

It's required for  a deep drafted 'bath tub' and bluff bowed general purpose hull.

Thanks ya'll.
Title: Re: 3 or 4 bladed prop.
Post by: Tug-Kenny RIP on March 26, 2012, 08:42:18 pm

I would use a four bladed Propeller where torque is concerned. This becomes more powerful than a three bladed one, on slower revolutions.

ken

Title: Re: 3 or 4 bladed prop.
Post by: Shipmate60 on March 26, 2012, 09:10:22 pm
What is the performance criteria of the motor.
Most 540 derived motors don't supply much torque and need revs to provide power/speed.
Fot torque consider either a larger diameter motor or multi-pole motors.
540's only have 3 quite small windings.
540's are usually more suited to 2 blade racing type props which allow for higher revs.
It is fairly easy to check if the motor is over propped, it will get hot quite quickly and will have a large current draw.
You havent stated what diameter prop you are thinking of using with this motor.

Bob
Title: Re: 3 or 4 bladed prop.
Post by: malcolmfrary on March 27, 2012, 09:51:37 am
4 sounds good, but a 545 rather than a 540.  The extra couple of poles makes a big difference.  A lot depends on the size of the blades and the size and performance expected from the hull.
Title: Re: 3 or 4 bladed prop.
Post by: essex2visuvesi on March 27, 2012, 10:44:02 am
If you want a slow running torquey motor in a 540 size can then this is the one
http://www.fusionhobbies.com/Carson-Poison-Truck-Motor-p/c906023.htm

I have one in my King Hauler truck and its a real improvement of the the stock 540.  Really improves the pulling power and also run times are inreased by about 10-15%
Title: Re: 3 or 4 bladed prop.
Post by: John W E on March 27, 2012, 01:46:26 pm


Hi have a look at the motors from Action go for the 555 motor
Have one in the MC ARCHER TUG driving a 4 blade 50mm prop on 7.2 volts :-))


http://www.modelboatmayhem.co.uk/forum/index.php?topic=27894.0



http://www.action-electronics.co.uk/stuff1.php

aye
john