Contra-rotating rotors as plan B Update of the Humming Man Project

Dear All,

As we are now have finished the belt drive design as you can see, we are now in the making of it. Once we have tested one unit we can see how it functions, (acceleration, control, stress, vibrations, etc..). But yes always there is to be 

a plan B. And good to advance in that direction too. That craft would be configured just like the original see earlier blog. But at each end iso one e motor with belt, there would be two motors:  one up one down (just like in some quadrocopters). This would be a compact alternative with more redundancy. 

The motors would be controlled separately and we can vary the top and bottom speed. 

We see at first investigation that contra rotating props can have some higher efficiency as 2 seperate ones. We also understand that the prop pitch of the lower prop needs to be higher as the down wind it receives from the top one can then better be used.  

Now the issue is: does any one of you have experience or rules of thumb or simple first effect formulas to tackle the issue? Would think that with the some of the drones this issue must have been studied?

Hope to hear, Best Regards, Winfried team www.TheHummingManProject.com

Views: 1395

Comment by Winfried Rijssenbeek on November 17, 2014 at 8:21am

hi Ed, this is the thing I wanted to know. Unfortunately, here in Kampala where I stay for an assignment I cannot open vimeo! Anyhow I worked on some literature and find a NASA publication quite interesting. They also use diagrams on relative speeds etc. However will be difficult to master 60 + pages formulas! 

Last question: how you judge the performance is it basically 2  times  lifting and 2 times the energy consumption as compared with single props of same ...

Thanks and will look at your designs asap leaving Uganda! 

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