So..... I guess you could consider me a bit of a nerd gone corporate sell out. I'm all for open source, home grown, new idea, etc..... but in the business world, it almost always means a loss of high availability and redundancy. So my brain is just wired that way!
What does mean for my ArduCopter? Motor redundancy!!!
I'm not looking for much wieght, don't need to add much power..... the camera and gear I'm lifting isn't very heavy at all. Its a Canon 5D Mark II and some really wide open lenses. Total weight is actually pretty stable on my quad with 4 880 motors and 12" props.
Here's the issue.... between the quad, camera, lens and other small gear.... that's like $7,000 floating around and a single motor failure sends some pretty nice gear into peices.......
So that's the question: What's the best way to build a stable quad that can sustain at least 1, if not 2 motor failures during flight and still be able to get back and land without flipping and hitting the deck hard??
The Y6 looks promising, but I wonder about loosing load capacity. I've heard rumors about an "X8" with the same style inverted motors at the Y6, and of course there's the normal Hexa and Octo configurations. Anyone like one over the other? or have an advice?
Replies
If you want redundancy, Y6/Hexa is not recommended. If you lose a motor you will lose considerable lift. I have built quads, coax quads, hexas and y6s. The only configuration that still actually flies very well in a motor-out scenario is the coax quad. I am sure an octo would also fly well, but I haven't built one (yet). If you are a 3D heli pilot then you can handle a motor out on a hex as it will be spinning. I really like the y6 for orientation purposes and for aesthetics, but if you insist on lifting gear with it, you will have to build it to fly, not build it to fail.
As an aside, if you are lifting a 5D with a quad, you are very likely underpowered. You should be able to pick up your payload at just over 1/2 throttle and I doubt that is the case. You are most likely at 3/4 throttle lifting a 5D, so you do not have enough reserve power. The 5D is a heavy camera, even with primes.
Is the X8 allready available through the code?
The problem here is the high disk loading (weight of the craft per area of propeller) so that when one thrust unit fails, it is so far out geometrically from the center of mass that creates quite a torque moment in the pitch or roll directions. Using longer props and turning them more slowly would help this. It would of course be a compromise in maneuverability, but if a stable camera platform is your goal, it's worth pursuing.