http://www.e-volo.com/Home.html
Love the yoga ball as a soft landing device, can't believe the pilot trusted his life to an RC controller though and he never had covers for all those props which would have sliced him up like a blender if things went pear shaped.
Awesome stuff, just totally jealous as we are trying something similar and they flew first :-)
Comments
Awesome! We can fly to school and office later!
@Nick Mann: The efficiency effects of a coaxial configuration are indeed negative, causing an induced power increase of 25% to 40% depending on the separation gap. That's why some of the small, indoor model electric R/C coaxial copters have ridiculously large distances between the upper and lower rotors (larger gap being better). The only reason to have two rotors share the same axis is to counteract torque in a small space without the complexities of a tail-rotor. I cannot speak to the intentions of a potential competitor, but in my opinion, using conventional model airplane propellers instead of something more aerodynamically appropriate speaks to expediency rather than efficiency. Most of this group are experimenters themselves and can look at the pictures of the craft in question and probably cite the Hobby King or Tower Hobbies part numbers for almost all of it. That said, I applaud their resourcefulness and daring.
I doubt they're gonna transparently share their specs in any big way, this is all business, and they've taken some big risks and done some hard work to find their current bird.
Website is claiming ten minute flight time and talking up a future with a fuel-driven generator giving it an hour plus.
As a bit of an aside, I wonder why they've decided to have no x8/y6/hexa12/octo16/etc. style set-up. Obviously the physics of the lift are very different when a rotor is operating in another's down-draft, but just how different is it? Are two piggy-backed props not worth the sum of the parts? Clearly these guys chose not to go the sandwich way, despite being severely squished into a field of threshers that could potentially be half the horizontal size. I don't suppose this is a topic to raise here.
What is cool is that it looks very realistic that multirotors could lift and deposit considerable weight. Is it fair to guess that the lift of each "ARM-quad" is proportional and could lift 20 KG or so on it's own? Plenty commercial application there.
i hope he crash less than me ...
great job
@Park Jungho
The people on this discussion did not build the craft. You should contact the people at E-Volo who did and ask them for more information. Then as a good citizen of this community, I hope you will then share that with us, in this discussion.
I can not find about motor and propeller infomation.
Check their site.
very amazing.
Please tell me this motor and propeller.
I want to make a multicopter has 30kg trust.
So I need informaiton of motor and prop.
the web site says it has a empty weight of 80 kg. including batteries.
It's hard to estimate the weight of that frame, but that's about 70 pounds of batteries, about 150 pounds of aluminum, 180 pounds of pilot, 50 pounds of motors, hardware and wire, and a 5-pound rubber ball.
I assume the E-Volo craft is using 32 inch commercially-made props (the largest I've ever seen), so figuring the total weight of their craft is 455 pounds, I calculate an induced velocity at each disk of 32.72 ft/sec for an ideal power of 1,262 watts. The best figure-of-merit I've ever measured in static thrust for a model plane propeller is about .35, so we'll give them the benefit of the doubt and call it FM=40. That's 3,155 watts at the disk. Assuming the efficiency of the motor is about 80 percent until it gets VERY hot, that's asking for 3,944 watts from the battery. I remember someone saying that they saw two 6-cell 5800 2 li-polys for each motor, so that means a 20.4 volt rail under load at 193.3 amps. Not counting Peukert effect or other losses, that means they've a maximum of 3.6 minutes of flight time in out-of-ground-effect hover.
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