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View Full Version : 45mm Props NEED HELP



monojeff
05-17-2011, 09:36 PM
They are graupner 45mm counter rotating props which are going to be pushing a twin 550 brushed 32" mono which I will be using as a retrieval boat.

The motors are proboat apache 550s.

I am not sure what the pitch is on the props but it says hydro on them which I did not realize when I got them.

Can I possibly cut them down or should I get new props??

monojeff
05-17-2011, 09:44 PM
I believe I found the prop somewhere and it says rise 54mm not sure if that helps.

sailr
05-17-2011, 11:18 PM
They are most likely 63 or 64mm pitch. If I were you I'd go ahead and try them. Run for about 45 seconds and then bring boat in and check temps. If too hot, get smaller props.

monojeff
05-17-2011, 11:28 PM
They are most likely 63 or 64mm pitch. If I were you I'd go ahead and try them. Run for about 45 seconds and then bring boat in and check temps. If too hot, get smaller props.

Yeah I think your right on that 62-64mm pitch from what I could gather.
You think I should test them under load of pushing something or test without first then test while pushing or pulling a boat.

monojeff
05-17-2011, 11:33 PM
Any thoughts on how many amps you think I will be pulling?

U1Racing
05-17-2011, 11:35 PM
Jeff, what are you planning to use as a rig on it to hook the boats to it??

monojeff
05-17-2011, 11:53 PM
Jeff, what are you planning to use as a rig on it to hook the boats to it??

I plan to make some sort of arms on the front of the boat to push them back to shore.

sailr
05-18-2011, 06:20 PM
Not sure how you would test other than on a boat! Any other test would be inconclusive.


Yeah I think your right on that 62-64mm pitch from what I could gather.
You think I should test them under load of pushing something or test without first then test while pushing or pulling a boat.

Boaterguy
06-05-2011, 07:37 PM
If it is a rescue, speed shouldn't be a problem, you could lower the cell count or something in order to bring rpm's down, propping then wouldn't be a problem.

egneg
06-05-2011, 08:53 PM
You could always run them through a gear box which will decrease rpm and increase torque.