Hi there,
I am thinking of using 300W 12V engines for my thrusters. They run at approx 1200 RPM. Any suggestions for prop size?
I was thinking of going for something like 100mm pc fans but honestly I dont have a clue.
Prop size?
Re: Prop size?
Hi Marcus. PC fans seem to get alot of mention. From memory, the blades are too curved for my liking, so work OK in one direction but poorly the other. The direction thing is in theory an issue for most props.
Given the low revs and high power of your motor, I would be thinking a heavily built aircraft prop of medium pitch could be good. Start off with maybe a 10-12 inch prop and cut the blades off to about 30-50% of their original length.
Could be that the revs are too low for that sort of prop to develop full thrust. Some folks are using RC ducted fan fans. If you could find one big enough this may be the go
Are you planning on using all of the 300 watts or are those motors just easy to get? Unless the ROV is big and bulky, that's alot of power
Ross
Given the low revs and high power of your motor, I would be thinking a heavily built aircraft prop of medium pitch could be good. Start off with maybe a 10-12 inch prop and cut the blades off to about 30-50% of their original length.
Could be that the revs are too low for that sort of prop to develop full thrust. Some folks are using RC ducted fan fans. If you could find one big enough this may be the go
Are you planning on using all of the 300 watts or are those motors just easy to get? Unless the ROV is big and bulky, that's alot of power
Ross
Re: Prop size?
Thanks for the reply,
Motors of that size is actually quite easy to find. Just check any 12-18V screwdriver. The manufactures don't shate thewatts though, so you will need to do some calculations.
I am actually not sure if all that power is needed. I was thinking of trying to mske a rov using as many parts as i could from my collection of junk.
It would be possible to run the motor without the gearbox and use smaller props but from my umderstanding less rpm means less dirt flying around.
The rov will be built in PVC using three thrusters. A large for forward/reverse, a large for up/down and a small for turning. It will measure about 700x400x400mm or so. Dont have a clue about its weight yet thoigh.
Motors of that size is actually quite easy to find. Just check any 12-18V screwdriver. The manufactures don't shate thewatts though, so you will need to do some calculations.
I am actually not sure if all that power is needed. I was thinking of trying to mske a rov using as many parts as i could from my collection of junk.
It would be possible to run the motor without the gearbox and use smaller props but from my umderstanding less rpm means less dirt flying around.
The rov will be built in PVC using three thrusters. A large for forward/reverse, a large for up/down and a small for turning. It will measure about 700x400x400mm or so. Dont have a clue about its weight yet thoigh.
Re: Prop size?
No worries. I have a collection of old cordless drill motors and gearboxes as part of my junk collection. They can be handy for all sorts of things, given they have a chuck and ESC as well. If you already have the fan blades, go for it - try them in a bucket of water on the end of a bit of threaded rod or something.
My first thought when starting to make my thrusters was to use a computer fan, motor and all but with bearings replaced with acetal ones and PCB and windings coated with epoxy. Would have had to fiddle with the sensoring to get reverse, only had one small fan though- motor not powerful enough. Then found how cheap the hobby motors and ESCs were....Choose carefully and research this forum if you do go the hobby ESC route!
Bigger props are more efficient, and moving more water but more slowly than a small prop would not stir up as much mud for the same resulting thrust. I think the fan blades if say 75mm dia or so and a drill motor and box would be quite useable for the size ROV you describe
My first thought when starting to make my thrusters was to use a computer fan, motor and all but with bearings replaced with acetal ones and PCB and windings coated with epoxy. Would have had to fiddle with the sensoring to get reverse, only had one small fan though- motor not powerful enough. Then found how cheap the hobby motors and ESCs were....Choose carefully and research this forum if you do go the hobby ESC route!
Bigger props are more efficient, and moving more water but more slowly than a small prop would not stir up as much mud for the same resulting thrust. I think the fan blades if say 75mm dia or so and a drill motor and box would be quite useable for the size ROV you describe
Re: Prop size?
I will give it a try.
Worst case scenario; It does not work well and I need to replace it.
Gonna start the build and see where I end up.
Worst case scenario; It does not work well and I need to replace it.
Gonna start the build and see where I end up.