[jtrout19]

So I have been doing some reading about co-axial multirotors. I read alot that they are inefficient due to the extra motors and esc and need for bigger battery and so forth. Why are there no build that use one motor for 2 props? It would not be that hard to set up. Does anyone know if this has ever been done before? Co-axials have always interested me and I want to build one eventually. So lets have a little talk about them and maybe some R&D. If your wondering how one motor can drive two props that spin opposite of one another I can get an illustration together.

That being said does anyone know if it has ever been done before?

[Aner]

I don't believe it the "extra motor" (extra weight) that makes the setup inefficient. It's due to two propps in which one of them is forces to rotate in turbulent air. The problem is also that the lower prop is forced to accelerate air which already has ben "accelerated from the prop above". The shape of the vortex from the upper prop also tenders to narrowing in shape due to wind velocity vs volume. That is why one usually place a higher pitch on the lower prop. Perhaps its more a theoretical problem. But if you're getting in to it, you will have to consider it. There are tons of info on the subject on the internet.

Aner

[jtrout19]

Interesting thanks for the information. I havnt yet delved to deep into the idea yet. But will be eventually. Thanks again