On Jul 30, 5:09*am, John Doe wrote:
"Morgans" jsmorgancharterJUNK.net wrote:
Look in places that talk about remote control airplanes, because
that is what even the man carrying experimental airplanes are
borrowing knowledge from, on the subject of electric flight. *It
is just at larger scales.

I believe that, but how come you never see a real airplane
standing on its tail? Looks like that would be a neat way to
simulate a Harrier landing, and takeoff.

Actually you can do it. It is just too expensive and dangerous.

As for your project. The best is to experiment with it.
As a starter, you should calculate the power that you need.
Power is a function of battery, not motor.
The motor rated power is the sustained power that the motor and
windings can withstand for along time.

the motor power is defined by rpm x torgue.
rpm is proportional to voltage

How much rpm can your motor stand for a short time, mechanically.

torgue is proportional to current. How much current can your motor
stand for a short time. Current creates heat so the limit is heat.
If you can put cooling system to this motor you can operate it at high
torgue, at least for a short time.


Propeller theory. Propeller is just like a screw. How far does it go
per RPM.
At low speed, the air need not travel so fast, so low pitch is
desirable. In order to increase the thrust, you need high volume
running at low speed. Long propeller.

You don't need maths. Just a sense of balance.

So adjust the pitch and diameter of the propeller to match the voltage
and current rating of your electric motor.

You can exceed these ratings, but take special precautions, such as
cooling the coils.
In fact I like to experiment with overcurrent and its effects. Over
RPM is dangerous because it is mechanical. Over current is just heat
which we can control.