I came across this interesting video:
As you can see in the video they have managed to control the coaxial design without using a swash plate and all the complicated mechanisms required for that. It looks like this is an excellent concept for very light weight systems. I do wonder how easy this can be scaled up into a device that can actually carry any additional equipment. This could be useful to obtain the under 2 kg UAV weight for the Canadian regulations.
Great link MarcS!
Very impressive, and that is in 1991!
Hi, interesting idea.
Back in my head I did remember something similar. After some search it turnes out it actually was long ago. It is called Keyence Revolutor by a japanese company, which actually also sold mini quadcopter over 20 years ago!!
The idea sound similar, by well timed motor pulses impose a blade deformation. Was done by a brushed motor and an optical encoder. If I remember correctly I read a report back then saying the motor did not last long because of the pulse load. Was a unique thing at the time!
Here are some links for all interested in a little history:
http://www.acuvance.co.jp/english/heli.html (this has the most technical information)
Got it Greg! Thank you! I missed the point that blades are actually hinged in two opposing positions on the video.
That makes sense. There is something new you can learn each day.
Going to their website may help you with understanding the system http://modlabupenn.org/underactuated-rotor/
Could you explain in more details the idea of pitch change, please? I am not getting it in whole.
It's a grea idea, that can be clearly very useful where lighter, simpler and cheaper is better (like in toys or very small uas). But i'll bet it won't scale very well and never have the same autority of a real swashplate controlled variable pitch blade, making it very difficult to use outside or in any real world condition.
awesome. one difficulty of small uav in this case I can imagine is the relatively small space to fit the equipments between these two motors, and how to put the antenna vertically.