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DraganFly III Gyro-stabilized RC Helicopter
Pronoun54 writes "It hovers! It spins! It spies!
The Draganflyer III weighs just 17 ounces with its high-tech stabilization system. "As an eye in the sky, the Draganflyer III can be used indoors or out, up to a mile away, to take aerial views of real estate, promote products at trade shows, or give the guy in the next cube a close encounter he won't soon forget." "One more advantage of the Draganflyer III: if you're grounded by bad weather, you can still open the throttle and hover indoors." Their site has videos of this thing in action both indoors and out. Seems like it can move pretty fast at top speed." The Times has a piece talking about the piezo gyroscopes (including purty pictures) that the chopper uses to self-stabilize.
Their marketing people must be extremely happy!
Here's a project on sourceforge (GPL'ed):
autopilot
"It's too bad that stupidity isn't painful." - Anton LaVey
NiCd's tolerate high discharge rates better than NiMH batteries, and FAR better than Li-ion batteries. They can also be charged faster.
You can discharge a SCR NiCd battery in four minutes and not damage it. Do that to a NiMH battery, and it'll be too hot to touch, and will be damaged. Try to do that to a Li-ion battery, and you'll ruin it the very first time.
Also, the NiMH and Li-ion batteries have a higher internal resistance. Voltage drop == discharge rate * internal resistance, so as you draw more and more amps, you get fewer and fewer volts. Eventually, you get less total power from the NiMH and Li-ion batteries, even though they have higher capacities.
I doubt these things will fly for much longer than ten minutes (if even that.) You're discharging the batteries at a high rate, so you need batteries that can handle it. And those batteries are NiCd's.
Some park fliers can use Li-ion batteries, and they can stay up for 30-60 minutes at a time. But they fly very slowly and have very little power. Helicopters and other similar vehicles are not so efficient.
I have been flying r/c gas-powered, gyro-stabilized helicopters for 8 years now. This is nothing new. Most people can buy a full fledged heli setup for $700 or so. Back about 5 years ago, solid state gyros (piezo gyros) came out and have made the old mechanical gyros seem slow and imprecise. For more info on "real" r/c helicopters here are some links:
. century.comh eli-world.comt aba-rc.com
.61 SX-H engine. Any questions, feel free to ask.
http://www.miniatureaircraftusa.com
http://www
http://www.heliproz.com
http://www.
http://runryder.com
http://www.fu
http://www.osengines.com
I fly an X-Cell Graphite 60 size helicopter with a futaba 9zhs (9 channel) computer radio controller, futaba gy601 piezo gyro, OS
Check out their Draganflyer X-Pro model.
Here's the google cache.
Only $4997! (no, I didn't miss a decimal point.)
Combine this with a fun GUI and we can chase osama out Afghanistan. So he hides in the tunnels eh? Just load up another GUI and down some
tunnels we go!
I had a similar craft called the "UFO", which was maybe 50% larger than this one, but exactly the same design. Four props, two counter-rotating, with fancy stabilization electronics.
I've flow planes, gliders, gas helicopters, electric helicopters, and mini helicopters, but this 4-bladed craft was harder than any of them.
The problem is with yaw stability. Any time I tried to do a fast straight flyby, the craft would slightly rotate (yaw) in the wind. It's exceedingly hard to visually see which leg is the "nose" and keep it forward.
That, and the flight times are abysmally low. The four motors weigh quite a bit, and use a huge amount of power to stay airborne.
That, with the difficulty in forward flight makes one prefer hovering, where power is used even faster.
All in all, a nice idea, but I threw mine out after crashing it repeatedly from disorientation. I even tried spraypainting the nose leg orange, no luck. It's that very slow sneaky rotation that gets the controls all goofed up.
A helicopter has a tail fin that helps orient it nose-to-the-wind in flight. This craft needs something like that before it can fly figure eights with the same ease.
Others have already pointed out the open source Autopilot project.
The Draganflyer is limited to 5 minutes because it's so small and light, and runs on batteries. If you go with one of the more established conventional helis, you can get longer flight times. The longest times are still achieved by combustion engines, using either model fuel or regular gasoline, and it's quite easy to achieve more than 15 minutes with one of those.
However, I don't think it's any accident that the Draganflyer has an unconventional four-rotor design - this allows it to avoid many of the instabilities that a regular helicopter suffers from, and probably makes the job of programming an autopilot for it much easier.
Still, computer-controlled regular helis, even fully autonomous ones, are possible and have been done. There's even an annual International Aerial Robotics Contest. The site doesn't seem to be responding right now (secondary /. effect?), but here's one of the previous entries, the MIT/Draper Autonomous Helicopter Project.
In the past, these have been pretty expensive devices to put together. Nowadays, as the Draganflyer proves, it's not as expensive as it used to be. The piezo gyros are pretty cheap - in the $100 range for a decent one. Building your own computer-controlled helicopter is definitely doable. The Sourceforge project is probably a good place to start, especially since it'll be a lot easier if it's not a one-man project.
This is gonna do to the haircutting business what McDonalds has done to dinner.
Bulk discounts at stadiums are the wave of the future.
Table-ized A.I.