[PSUBS-MAILIST] propeller size

[hank pronk via Personal_Submersibles]

 Thanks guys, I do have an amp gauge on the drive motor and at 24 v the motor is not working hard at all and it stays luke warm.Hank
    On Monday, November 13, 2017, 8:31:38 PM MST, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  
 
 Hank,I am not sure but I think that would be OK. If you can measure the amps you are drawing & the speed your sub isdoing on the surface, you could make some conclusions from that, &I think that is the only way to get some really good results. A bollardtest in a pool doesn't take in to consideration the forward movement ofthe submarine, & there are also various effects from the sides of the testpool & circulating currents. I will have to do this with my thrusters but itis not perfect.If you can test the amp draw & speed at both voltages then you can say"Is the gain in speed worth the extra power draw on the battery!"Are your propellers plastic? I don't think they are but as an aside, I have wondered whether the tips bend when you put an extra load on them. If say you are producing 100lb thrust, that thrust would be distributed across the propeller & surely they wouldn't work efficiently with too much load on them!Alan


Sent from my iPad
On 14/11/2017, at 2:37 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:


Hi All,Gamma has always run on a 24v 2 hp motor.  The 24v 2 hp motor is simply a 36v motor run on 24v with reduced rpm.  I am thinking about running the motor on 36v to increase surface speed.  This is very simple because the controller will also run on both voltages..  My question is, will the propeller still be sized correctly.  I am assuming the extra rpm is supported by the extra hp, or am I over simplifying it.Hank

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