Twin motor rc mixer need... any suggestion!!!

Nelly

I am currently working on a remote control airplane with twin electric engines. I would like to control the amount of thrust to each engine by mixing the throttle with the rudder channel. I believe the best place to do this is between the radio receiver and the motor esc, which would require two inputs and two outputs. I have no previous experience with programming. What are my best options for learning and creating this mixer?

Franklin

Write it out as if you were explaining it to a person with no knowledge of airplanes and this person had to accomplish what you want. Take what you get and group it into small tasks and then code those tasks.

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- Stephen

Carl Hayes

Franklin said...
Write it out as if you were explaining it to a person with no knowledge of airplanes and this person had to accomplish what you want. Take what you get and group it into small tasks and then code those tasks.

That is the wisest and best advice I've seen in a long time.· It's so easy to do, and it so greatly clarifies your thinking and prevents so many bonehead errors.

One way to follow that advice is to write it out in words.· This is OK but is slow.

Anothe way is to create a simple flow chart -- which is just a shorthand form of those instructions for the beginner.· I always do a flowchart for any program that I expect to take more than ten minutes to write.· It saves me untold heartburn.· Usually it's just scribbled on a palimpsest -- I'm always running out of paper -- but it makes all the difference in the world.

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· -- Carl, nn5i@arrl.net

Carl Hayes

Incidentally, if you do this (use differential power to enhance the turn), I'd be most interested to hear whether the result is a sudden inside·snap roll, and whether the Earth rises up to smite thee.· In many airplanes, it would.

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· -- Carl, nn5i@arrl.net

Post Edited (Carl Hayes) : 2/20/2009 5:10:34 AM GMT

sylvie369

Those little tiny foam "Airhogs" RC planes use differential motor power to turn, but that's with no rudder or aileron control at all. They work okay, but I don't think it scales up very well.

Nelly

Would the Bs2 be the best for creating this? I was thinking of getting the discovery kit to learn the process and then using the parts to build it after.

I am building a V-22 Osprey and the variable motor control will be mostly for hover mode to balance and manuever the airplane.
Should be awsome if i can get it working.

Carl Hayes

Wow, that's a neat project. I imagine -- translation: I don't have a clue -- I imagine that the V-22's aerodynamics is about as much like that of other twins, as tennis is like three-cushion billiards.

I would think this would be feasible with a BS2 if it is feasible at all.· The Marine Corps had doubters, but the V-22 does fly.

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· -- Carl, nn5i@arrl.net

W9GFO

The easiest way to accomplish the mixing you want is to use the programmable mixes in your transmitter. Although since you post the question it is likely that your transmitter doesn't have that feature. Consider upgrading your transmitter to a 6 channel or better. They nearly all have programmable mixes these days but check to be sure.

Another alternative is to use a mixer like that used for flying wings or V-tails.

As for the V-22 model, I am sure you will need at least a roll gyro. Great Planes makes a small brushless motor intended for foamies called the V-Pitch. Using a pair of those with the speed governed, adjusting the pitch instead of rpm would probably work better. You can also reverse the blades on one so that the props are counter-rotating. In that case you would not be mixing the throttles at all.

Rich H