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This thread is privately moderated by Jack Crossfire, who may elect to delete unwanted replies.
Jan 12, 2009, 08:59 PM
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Things R better in 4's

Our state of the art computational fluid dynamics system showed the penta rotor would suffer from extreme weather vaning of the tail rotor. Yaw provided by the 2 front propeller torques would not be enough to overcome weather vaning. In the worst case, U would have 2 front rotors stopped & be completely unbalanced again.

Moving the tail rotor closer would make no difference. You'd watch a line of 3 propellers mysteriously turn perpendicular to the wind.

U can pile on a servo to control yaw by deflecting tail rotor thrust & add more weight.

The main problem is preventing rollover on the ground. U definitely need heavy rotor shrouds. Just because Draganfly sells underslung propeller craft for $17,000 doesn't mean you're not going to break tons of propellers. Notice how shows plenty of hand launches but never the landings?

Finally, we have shortened flight time from lifting a 5th motor.

There's not much U can do to increase quad rotor performance. U can reduce flight time. U can increase weight. U can reduce payload. Everything you can do to the basic 4 rotor design is just moving performance from 1 area to another.

Your best option is more software to handle unbalanced payloads gracefully. Others don't clamp PWM values. They reduce collective when a PWM is saturated. Thought that was stupid so we didn't implement it, but clearly a powered attitude controller is different than a swashplate.
Last edited by Jack Crossfire; Jan 12, 2009 at 09:19 PM.
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