Placing the motor in the board?


#1

So I know that there are a ton of variables we don´t know about yet. I expect that I will have to play around a lot with different gearings, props and ducts. Finding tiny yet powerfull gearboxes is difficult and expensive. So I thought why not put the motor in the board and link it through the shaft? That way there is enough space for the gearbox and different motors. You don´t need to rebuild your propulsion system from scratch every time you change something. The only issue of course is cooling and the noise. I don´t think you could do a lot about the noise, but for the cooling I was thinking about a little dish on top of the board that would fill with water from time to time and directly cool the motor. Alternatively you would have to put pipes into the mast and a pump.

What are your thoughts?


#2

I’ve tossed this idea around too… heat and torque are my concerns. The mast would experience high torque, especially when starting from a stop. An engineer explained it to me that the force is as if the prop is being held still and the motor is trying to turn it, the mast would have to hold that torque.

The 90 degree gearboxes have lower efficiency which will generate a lot of heat. In theory, that can be dissipated under water.


#3

That is true. The spinning shaft in the mast will make the mast torque. I am not sure how easy it is to torque the mast though. Never had one in my hand. You could use a belt drive. That way there is no torque, but it needs more space.