Hovercraft design parameters

Question

My washing machine broke down recently, and they replaced the motor. The old motor was not broken, as far as I could tell; the sensor that told the CPU that the drum was balanced was what was out of order. At any rate now I have a perfectly decent rotor and stator, and I started thinking about how to recycle them. Apropos of not much of anything, I started thinking about a one‐man hovercraft.

What I have so far;

• The washer service manual specifies a max RPM. I assume this is completely useless because it refers to the motor and drum assembly and I’m not going to dismantle my washing machine to weigh the drum. I can call the repair guy and find out how much the drum weighs, but I'll only do so if I find that the calculation takes too long (I don't want to bother him on the weekend).
• The required lift force is equal to a > 9.8*(mass of hovercraft + mass of rider), where a is some acceleration over a time T. Where T is simply the amount of time necessary to move vertically from rest to a position above the ground equal to the height of the deployed skirt. In other words solve $Y=Y_{0}+V_{0}T+0.5aT^{2}$ for a known Y, zero initial velocity, and $a=\frac{F}{m}$.
• The friction and air resistance are negligible, however since increasing horizontal component of motion reduces vertical component, thrust should be higher than what is required to simply achieve lift by some factor.

Questions;

1. How can I evaluate the power of the motor? I have not been able to find specs online so far. Does it even make sense to talk about the power of the motor without knowing the power supply? Is there a maximum and minimum power output? Alternately, is power even a relevant parameter, or should I be concerned solely with RPM?
2. The friction and air resistance are negligible, however since increasing horizontal component of motion reduces vertical component, thrust should be higher than what is required to simply achieve lift by some factor.
3. What factor must I exceed vertical thrust by in order to move horizontally?

Answer 1

Designing the lift system for a hovercraft isn't actually about the mass and the acceleration, it's about the pressure required to lift the hull and the rate at which the air leaks out from under the hull and needs to be replaced. Together, these determine the lift power required.

Horizontal motion is a completely separate issue, which requires knowledge about the friction of the skirt, aerodynamic losses, the slopes you want to be able to handle, the mass of the craft and the acceleration you want to be able to achieve.

While it may be possible to use a single motor for both functions, in conjunction with ducts and baffles, it's often simpler overall to use two separate motors.