Heres a "little" project I started a little less then a year ago. It all begin with design requirements of a quadcopter with a 10 pound payload for a one hour flight time and ended up with a gasoline/variable pitch build. At the time and since then I've come across many blogs, discussions, pictures, and videos of people who have tried this kind of build and only one or two videos of anything remotely proof of concept ( a nitro and an electric single engine/motor variable pitch build that simply made it off the ground). Since as of 10 months ago I did not even know that diydrones.com existed I decided to wait until I could show up with my proof of concept. To the best of my knowledge this is the first successful gasoline powered quadcopter. I am a mechanical engineer and am working with a computer scientist and computer engineer who have their own equally ambitious plans. I have plans on selling these to farmers and other researchers some day but in the mean time I want to to lend my experience to anyone attempting a similar build and would like to see all those people who have started these builds to be able to finish.
This picture was taken on 4/17/2014 and was my first full system test. It was more then happy to to fly at the end of it's leash (which I made too short for it to hang itself) for 20 minutes before I landed because I smelt something burning. The burning turned out to be the clutch pads, which were entirely gone. Must have been too high pitch for not enough throttle.
My second test was less impressive. Lets just say that there are dozens of bolts that individually keep bad things from happening and it only takes one missing Loctite to vibrate out and let the bad things happen. I'm at least proud to say that after test two I am only waiting on two pairs of rotors in the mail.
At the moment This is what I have:
Control system- Arduino Uno and potentiometer with a spool of speaker wire in between (remember, mechanical engineer)
Engine- Zenoah G290RC
Gear Reduction- 17:57 (calculations based off having equal rotor tip speed as RC helicopters with the same engine)
Rotors- 325mm symmetric carbon/glass fiber main blades for the T-Rex450 (as cheep as I can find)
Rotor grips- Tail pitch assembly from Align 700/800 series
Servos- Protek 100SS (both for pitch and throttle)
Power Distribution- miter gears and torque tubes
Gas Storage- Two Danhakl Design tanks 32 oz each
One way bearings in each arm
Plans and ambitions:
3DR Pixhawk control hardware (my friends are scrapping the firmware) -or- RoboVero and a Gumstix (we have both hardware but are probably a month out from having a respectable control system).
Fully autonomous system
Self learning algerithiums
A foldable design that fits in a 2'x2'x4' box with 5 minutes in or out
Multiple test flights around an hour long
The ten pound payload
Individual rotor RPM sensors with Hall Effect switches
Sonar distance to ground sensor
50 miles per hour
Thoughts, comments or questions?