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Dynamic inflow speed

Dynamic inflow speed

Dynamic inflow speed

Greetings all,

       Here's a problem I've been working on for a bit - what do people know about the rate of change of the inflow through a rotor?

       I have a weird case where I'm slowing down electric motors that directly drive my rotors. These are fixed pitch blades, so changing the motor speed is how I vary thrust.

       What I'm finding when I do the dynamics, though, is that the decelerating rotor dynamics are much slower than the accelerating rotor dynamics.  A theory I'm testing is that the inflow through the disc is actually driving the rotor like a turbine in the time it takes for the flow to slow down.

       Has anyone seen anything like this before?  I've got a good model of how the blades work in various flow regimes, but it's the dynamic behaviour of the inflow speed that I'm not sure of.  There seem to be plenty of references for steady state flows, but not that much for dynamic flow in hover - alternatively, I may not be looking in the right places.


       take care,


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