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Hi Vance. You're right. I'm using Madison Ave numbers for thrust and
won't really know how much until I get them wet.
As for the low speed maneuvering from a big, single prop.....it is more
efficient ( in power used ) but I would think also less precise.
Another thing to consider is the ability to stop rotation and then reverse
it. A larger prop will take more time to come to a stop, and require more time
and power to start. I think a short burst of power applied to a large prop would
be less efficient than the same power applied to a small one.
My guess is that the efficiency ( thrust per watt ) on a larger prop is
realized only after reaching the optimum level for that particular prop.
Start-up and reversing to stop, or " bumping" the prop to move just a
little can't be efficient, and the larger the prop....the more energy is used to
start it.
Anything that spins has a gyro effect. The larger it is, the more power it
takes to get it going.
If we wanted to move just 6 inches and stop, and do that 20 times, it seems
like it would be tough with a single big prop.
A small prop could be bumped with much less power consumed.
As for steering, you're right again. Trying to steer with just thrusters
would be difficult to hold a straight heading, and the constant throttling up
and down would take lots more power and waste a lot. Air or hydraulic rudder and
dive planes are the obvious power savers.
Let me know what you think. Frank D.
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