How to select propellors?

[Louis_Cha]

Hello all,

I'm wondering about the criteria you used to select your propellors? Bearing in mind that I am on a tight budget here .

I'm looking at the R1472 Dynamic Propeller
Robbe 3 blade 50mm propeller
Diameter: 50.00 mm
No of Blades: 3
Pitch: 42 mm
Thread: M4
http://www.cornwallmodelboats.co.uk/aca ... llers.html

Any advice?

[Louis_Cha]

Also is there any reason to use boat propellors rather than quadcopter props?

[sthone]

I think there so many factors involved I don't think you'll find an exact answer to that question other than trial and error. (least I have never found one in all my years.) That being said in all my trials I find that 50mm Robbe prop to be the best all around prop. (at least for bilge pump thrusters) I haven't gotten around to trying it on any of the brushless motors I have yet.

As for your second question.... boat props are made to move water where quad-copter props are made to move air and with water being more dense than air quad props would probably just draw more amps and not move as much water. I do know people who have cut down airplane props and used them but they still are not going to be as efficient as a boat prop.

-Steve

[Louis_Cha]

Thanks Steve, these props have been suggested to me, what do you think of them?

http://www.hobbyking.co.uk/hobbyking/st ... eller.html

Otherwise I was going to go with these: http://hobbyking.com/hobbyking/store/__ ... _bag_.html

There is quite a cost difference, but what about the performance?

[Louis_Cha]

Sorry wrong link!
These props: http://www.hobbyking.co.uk/hobbyking/st ... eller.html

with this motor:
http://www.hobbyking.co.uk/hobbyking/st ... Motor.html

this prop adapters:
http://www.hobbyking.co.uk/hobbyking/st ... _35mm.html

and these ESCs:
http://www.hobbyking.co.uk/hobbyking/st ... verse.html

[scubersteve]

I would just refer to the "draw, thrust and components" thread where others have already tested several combinations of motors and propellers and posted the results.

[sthone]

That looks like a ducted fan prop, again those are designed for moving air not water. With that many blades.... while it might move a lot of water on a 1100 kvm motor it also going to draw WAY to many amps and you'll more than likely just burn out your controller.

Stick with a boat prop.

-Steve