Counter rotating cat how too?

[Mph621]

I have a 35" cat that I am making duel motor. Running two 3674 2200kv motors 4s. How do I counter rotate and also prop size to start out with would be a great help. Thanks in advance!

[kfxguy]

X442 or x440 props are good starting point. They sell counter rotating props in this size. You'll need a regular rotation and reverse rotation shaft. You don't have to have a reverse rotation collet.

Also they sell cnc props in those sizes. They work pretty decent

[Mph621]

I have the shafts and the CNC would be great I'm not good at sharpening props

[dasboata]

I can do up a set of props for you PM me if interested thanks chris

[SD Eracer]

Make sure to set which side rotates where.

Most prefer to rotate inside, especially for SAW runs. For example, the left prop turns clockwise, the right prop turns counter-clockwise. However, some people setup to rotate outside for better handling for sport boating.

Also, make sure you use the correct flexshaft wound for the correct rotation. If you put the wrong one, it will cause the water to get sucked into the boat from the stuffing tube and also risk unraveling the flexshaft winding.

As mentioned, the opposite rotation collet is not needed. It's just to prevent accidentally loosening of the collet by the spin rotation, however if you properly tighten the collet, it won't be an issue and you don't have to always try to remember which collet turns which way when trying to loosen or tighten it.

A good starting prop for your boat are Octura X442 R&L rotations. They are $14 each, super easy to sharpen and balance, and relatively mild. Your setup with those props on 4S should get you about 70 mph or more. 5S will probably get you 80mph.

Make sure your boat's hull has been reinforced to handle these speeds in case of flip and that your hatch has locks. If no locks at those speeds, you will lose your hatch and flood your boat.