Unknown 42" mono converted to electric

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LibertyFrancis

Well-Known Member
Joined
Jul 9, 2021
Messages
67
Installed a 1.7 pitch 60mm prop.

It was a total turd. I knew it would not perform well, but I wanted to stress test the ESC and motor. Now I have a better understanding how far I can push things safely, how many speed passes I can make, etc....

This was a good test to get the ESC cranking out over 300a and confirm both the ESC and motor will stay cool under heavier loads.
(single 4s LiPo battery)

53 mph m1760.JPG
several runs.JPG

53Capture.JPG
 

LibertyFrancis

Well-Known Member
Joined
Jul 9, 2021
Messages
67
Found myself in a odd funky place with this 42" mono.
4s is not enough rpms for this motor 18k - 25k and running 6s I am likely to go faster than this hull can handle 70+ mph. It appears it would do 80+ with most of these setups and I don't want to destroy this cool old boat.

Given this boat wont safely run higher speeds (70+) I am going to focus on my rigger project from now on where I can really explore high speed.

Some interesting data from the runs on 4s I have recorded over the past few months. I concluded with more RPMs and higher speeds these props would probably spread their MPH results much further.

Prop notes:
All are sharpened and balanced.
x645 is a dasbota unit (most efficient of the bunch)
x447 was reduced to 45mm and I put one small bend into it. Estimated to be 1.6 pitch.
2250 had a large back cut on it around 25 degrees angle as I was testing transom lift.

Note - I want to run the V955/3 one more time as I think it had a few more mph in it. (if it does ill update these graphics) The pond I had tried that v955/3 prop on was much shorter and had some fountain obstacles.

MPH Capture.JPG
Amps are the amps at peak speed after acceleration peaks die down.
AmpsCapture.JPG

Voltage drop Capture.JPG
 
Last edited:

Wasted wages

Well-Known Member
Joined
Jan 2, 2006
Messages
1,698
Something doesn't look right .....

Between the X645 and the 1760...
Double the amps for only 5 mph increase ?

And between the X447 and the 1760...
66 amps for the same 5 mph

And three props with the same mph, with variations of 139 amps high to low ??

RPM's must be wildly different...
 

LibertyFrancis

Well-Known Member
Joined
Jul 9, 2021
Messages
67
Something doesn't look right .....

Between the X645 and the 1760...
Double the amps for only 5 mph increase ?

And between the X447 and the 1760...
66 amps for the same 5 mph

And three props with the same mph, with variations of 139 amps high to low ??

RPM's must be wildly different...

I was a bit surprised to see the speed results come in all so similar.

The amps seem reasonable to me given the extra size of the prop. That 1760 has some thick blades compared to the little X series props.

Bigger props turn less RPMs as expected. The V955/3 I believe has a few more hundred rpm in it. I hope to get out and re-test that one Saturday.

1635538767621.png
 

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