So, decided to install a Pixhawk in a Bixler 2 air frame, and looking for pointers.
How sensitive is the Pixhawk to vibrations in an airplane, as opposed to a milticopter?
What should I mount the Pixhawk with? Gyro pads, some gel, some anti vibration mount. Not a lot of room for a anti vibration mount though.
I mounted a PixHawk in a Bix3. To make a long story short: just mount it to the foam fuselage, and I think you’ll be fine. You can both secure it to the “floor” (tape, glue, velcro) as well as wedge it between side-walls.
I recommend checking your vibration on your first flights after mounting, but I mounted this way and it was well within the limits.
I do have some foam that needs to be removed so I can get it where I want. I am trying to get it just below the main wing, and will likely clearance out some the foam. I am also thinking I will have to mount it upside down and open up an access hatch in the belly so I can have access to the Pixhawk and the wiring.
I think that’s an excellent idea. I wouldn’t struggle too much (removing foam) to get it “exactly” below the wing as I think anywhere in that fuselage section is close enough.
Another tip from experience: If your canopy is held on by magnets, remove those and use tape or something. The magnets mess with the compasses.
Have you seen this? http://ardupilot.org/plane/docs/a-high-quality-bixler-1-1-build.html?highlight=bixler It’s for a Bix1, but is great for getting ideas for where/how you might cut that side/belly-door for accessing the PixHawk.
Not going too crazy, just planning to have FPV gear, telemetry radio, and battery up front, Pixhawk behind that, just trying to avoid the major bulkheads in the fuse.
Yes, I have seen the bixler 1.1 build. That’s where I am getting some ideas from.
I’m finally getting around to updating that article. I had an accident that just about did me in, so I haven’t been doing much the past couple of years.
I concur about not messing with placing the autopilot directly below the wing. There are so many peripherals that you can move around to get the CG correct that it’s not a big deal. Also, I have noticed in my latest build that the code handles vibrations soooo much better than two years ago. I would stick it with some good servo tape and forget it. I used to like 3M outdoor mounting tape, as it works really well for all of my heli builds, but it does have one flaw: it tends to let go when it gets cold. That’s scary!
Lastly, if you’re interested, I can post my motor/prop/battery combo. You won’t believe it, but I got my Bixler 1.1 up to 80 minute flights at 12 m/s. I would finally get bored and watch a movie while it circled around overhead for an hour and a half.
Yes Please! Those are incredible numbers, nice work.
80 minutes in a Bix 1, yes that is a nice flight. Yes please post… I have a feeling LiON batteries are used
I used an Aerosky 2217-800kV motor and APC slow flyer 8-4.7 prop. The motor was a cheapo that I got from some heli store. I cannot find that motor any longer. I found a motor that will probably be pretty close http://www.buddyrc.com/sunnysky-v2216-12-800kv-ii-brushless-motor.html
I wrote another how-to on eCalc that has the same problems I’m trying to fix on my Bixler page: broken links. http://ardupilot.org/plane/docs/ecalc-motor-and-prop-efficiency-guide.html
I highly recommend paying for eCalc and using it to pick out your motor and prop. You plug in the motor variables, and it spits out the best prop. You cannot believe how making a very small change in the prop or motor can add or reduce your flight time drastically.
I’d like to fix those pages ASAP, but I wrote them in WordPress, and now the community uses GitHub, which is a monster for me to learn, but I’m tryin’.