Myself and three other Mechanical Engineering students are in our last year of college and we wanted to go out with a bang.... So we though, what would be fun to build as a senior project?
Well, we decided unanimously on building a heavy lift gas powered quadcopter. It will have a payload of 50lbs, variable pitch to allow quick maneuvers and two 12.5hp two-stroke hobby motors running parallel. Each rotor head will have four 435mm rotor blades making this UAV one big quadcopter measuring roughly 40" in length. The four of us are really excited to finish and watch it fly. If you are interested check out the links below.
Kickstarter:
web page:
Facebook page:
Comments
Robero,
That is an interesting set up. Thats going to be very similar to ours it looks like with the exception of four rotor blades. I found semi-symmetric rotor blades from spinblades but they only have them in one direction. I would like to speak with you regarding your gearing and drive train if you have time?
Gary
We will want to get Desert Aircraft motors because they are in Arizona and seem to have a decent reputation. The only thing is they have a price tag to match. We were hoping to contact them and maybe (fingers crossed) they could help us out.
Luke and anyone that is helping us financially, I can't thank you enough. We are working hard and the financial support helps allow us to focus more on the guts of this project. I also want to thank everyone for the technical support and great ideas.
A little research shows that two of the most significant problems are alternator / generator weight and efficiency.
Normal efficiency for alternators is in the 50 to 60 percent range and normal weight is on the order of about one pound per hundred watts. 70 percent efficiency can be achieved but usually only at considerably below rated output.
Although it is possible for generators to achieve higher efficiency, they tend to weigh considerably more for equivalent power levels.
In off the shelf current commercial alternators a 5000 watt lightweight high efficiency one would weigh over 50 pounds. Obviously that just isn't going to work.
Newer brushless generators and alternators will probably need to be designed specifically for these applications to have any chance of being practical.
As I said above if anybody knows of anything that is already out there, please mention it. Car alternators are high current, but low voltage and are generally under a thousand watts and 5 or more pounds with 40 to 60 percent efficiency.
I found a swell 10,000 watt one, now if only didn't weigh a hundred pounds.
Gary, I hope you're right and I'm wrong because I just backed it on Kickstarter. :)
I believe Brad Hughey is planning on using a gas electric generator system for his man carrying multicopter.
They may not make it anymore, but several years ago there were several sizes of Wankel type rotary model engines, I believe including dual rotor models. However, even if you could find one of these I would not recommend it. They never got the seal problems adequately solved on full sized engines, you can bet model engines are worse.
Continuing on the gas / electric idea, the key would be a light and efficient enough generator or alternator so that the conversion from rotary motion to electricity was sufficiently efficient to be practical.
Super Capacitors could smooth it out sufficiently for use.
Basically if you can find the appropriate generator / alternator all the rest of the stuff exists with sufficient capability to make it practical.
Both the mechanical and gas electric approach are feasible and both have significant advantages and difficulties.
If anybody knows of a truly light, efficient appropriate and efficient generator or alternator in the 5 to 10 horsepower class I would certainly like to know about it.
I respectfully disagree with Luke.
Although conventionally in helicopters Pitch is not used to induce Yaw, nonetheless, the more pitch, the more torque reaction, the more yaw force.
2 opposite same direction rotors with more pitch and other 2 rotors spinning in the opposite direction with less pitch = unbalanced torque reaction = spin of copter body in direction indicated by rotors with more pitch.
Just wanted to state my opinion for the records, you guys are going to prove which one of us is right.
One of the main benefits of a quad copter is avoiding the cost and complexity swash plate - this seems to defeat the purpose of going quad.
Gabe,
I'm glad the option of an engine to generator came to mind, it seems like a logical options for several applications outside of multi-rotors. But I guess a high RPM gas engine without a transmission is the most efficient. Plus a hobby sized rotary engine doesn't seems to be available, let alone a mini diesel engine.
This was new Propeller + Servo controlled special blade.
http://www.virtualrobotix.com/photo/sab-custom-blade-from-hg3-v2
This was the video of first test of HG3-2 :
Good Luck Guys,
we yet develop a fliying prototype two years ago see this link :
http://www.virtualrobotix.com/video/hg3-willy
The next revision could have a gas engine see this blog post :
http://www.virtualrobotix.com/profile/GiuseppeDAngelo?xg_source=pro...
We stop the development because was a complex project and need a big inverstment for continue the development. Our main problem was the trasmission from gas engine to propeller .
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