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A friend is trying to determine what prop to use on a large 48 inch Zelos catamaran that he recently acquired. He has swapped the original Proboat 56x87 1000kv motor for an SSS 56x104 1000kv motor, and will be running it on 12 cells. (Originally designed for 8 cells.) Looking for a good sport or oval racing prop. Any ideas?
Something in the 50mm to 57mm range, like X452 or X457
Thats a hot setup even for a SAW twin cat. I'd consider dropping to 8S or exchanging the motor for something more like 700KV at 12S and then re-evaluate prop choice.
12s not a good idea with 1000kv. That boat won’t even handle that kind of speed. Also what controller?
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1000kv would be good with 8s. The octura x452 would be a prop that he could try on 8s.
OK. I'
ll pass along these suggestions. Thanks
Seen one on youtube doing 63 mph on 8s and a ABC 2015 prop with original motor/esc.
But if you dobble the speed you will need 8x the Watt.
so going from 8-12s, (everything else equal) would be a teoretic 50% increase of speed. so it takes 1,5x1,5x1,5 = 3,375 x watt. But as your voltage goes up by 50% your amp-draw will be 2,25 x what it would be on 8s.
If you want to go 12s. but not go any higher in A-draw, (asuming a ABC 2015 is the most the ESC can handle). you would have to go from a 51x1,5= 76,5 pitch to 76,5 : 1,32 = 58 pitch or a 41-42 mm 1,4 pitch, (it would move the water but not the boat).......
With a 400 A ESC you could still use a 51/1,5 or something around 55/1,4.
An example from a twin mono: 47" and about 19-20 pounds. Setup Tp 5840s/1600kv. 55/1,4 mm props.
https://www.rcgalleri.dk/fotoalbum/o...c/39783-til_en
4s= 20738 rpm. 6s =29338. rpm increace was 41,5%. speed increase 42-43%.
According to teory watt should increase 1,42x1,42x1,42 = x 2,86.. And because of the about 50% increase in voltage the amp-draw should increase by 2,86:1,5 = x1,9....well 144,2 x 1,9 = 273 A... Not far from the 270 A measured...
I will like to add something. If you increase the voltage by 1.5 the amp draw will increase by 1.5 too. If you double the voltage the ampdraw will double too.
I have tried these scenarios and measure the ampdraw.
You can almost double the speed by doubling the voltage. At which the input power is almost 4 time higher when doubling the voltage.
Another thing I learned electric motors power have mostly to do with the rotor magnet strength and the stator metallic area. All the winding does is magnetize the stator.