Howdy, I just bought a trex 800 gasser and have some questions. I'm trying to decide on a autopilot that wont break the bank, or atlest not too much ;). I've been thinking about using the pixhawk, naza h, or maybe a wookong h. I like the pixhawk but nervous how reliable it is to work out of the box without crashing on the maiden. The naza h is nice but I need to find out how to add vibration damping just like with the pixhawk so it wont flip. The wookong h is really expensive but might be worth it if it saves me a crash and is reliable. I'm really trying to be careful about reliability because this is a 800 size gas heli and could really do some damage! What you guys think? Is it worth saving up for a wookong? Has anyone had great results with a pixhawk on a gasser? How would you mount a pixhawk with all the vibrations?
Thanks!
Aaron
Replies
The Naza $270, Naza with GPS $500, Wookong, $1250, Ace one $3200, Ace one Waypoint $11200.
Pixhawk with telemetry and GPS that can do the same as the Ace one Waypoint $380. (Arducopter doesn't have a governor and only can beam back 1 voltage and one current without modification).
I run a pixhawk on my electric 800 because I wanted to do Full Auto flight plan from take off to land. $380 or $11,200?
The Naza solutions are just too expensive. $$$ for each additional capability.
Dampening is really important. The helicopter itself is easy. The motor is, I guess, a little tougher but Rob Lefebvre has a (proprietary) solution. I've found some great (and cheap) ways to reduce transfer of vibration to the unit.
Really, if your satisfied with the low capability/cost ratio,go with DJI. But I'm sticking with pixhawk.
Yea, I love the pixhawk but am nervous throwing it on their with the gas motor and all the vibrations. How would you eliminate all of it? I just like something, simple,efficant,will work and not crash on the first flight! And very reliable! I love the pixhawk and the APM and use them on my quads but am scared to throw it on a gasser 800 sized heli. The wookong h is $700 without GPS.
Thanks!
Aaron
Isn't the GPS what makes the Wookong better than any $500 Flybarless?
I've never built an 800 gasser before, but first I would balance the props really well. Then I would mount the Pixhawk with a good dampening material. The best I've ever found is pipe insulation from Lowes less than $5.
I would orient the pixhawk so that the worst vibes were not in the Y direction because the rectangular case seems to make the y axis shake a little more. Rob discovered that dampening the GPS is also essential on a Gasser. You can also make a jumper system to avoid the vib transfer of all those beefy servo wires.
If you started from the ground up, you could isolate the motor from the heli like Harley Davidson's new motor mounts, but that's too much for our application.
I'd do it (and probably will). You can tell before liftoff if the vibes are going to be bad. Shaking antennas, huge altimeter errors, and a heli that leans near hover pitch. Just throw it back down and check your IMU logs.
Also helis with moderate vibe problems fly just fine in stab but behave badly in any alt hold mode (don't switch unless you can recover from a rocket up or down).
Talk to Rob Lefebvre. He's done it. He might be able to steer you straighter than I.
I would get the GPS later, the main thing I want is just the alt hold and auto level and maybe GPS if I get super lazy trying to fight wind all the time :D I also was going put a ezuhf on it, so I get a soild and diversity singal. I really like the idea of saving $300 using the pixhawk but its never be proven to be reliable on a gasser.
Thanks
Aaron
I would like to use the Pixhawk on my gaser but I am also kind of scared that we could crash on the maiden flight. Plus I would like to be able to build a vibration proof, waterproof case for the Pixhawk similar to the new DJI A2 M. I will need the system to work in the cold.
waterproof would require an alternate baro altimeter,
Looks like we both want the same stuff ;) the ace one is nice but that is really expensive!