Howdy yall, I have all but scrapped my quadcopter UAV project due to a problem I cannot seem to lick. Thermals from grass fires.
The Copter does pretty good flying in regular calm air but if it gets close and by close I am talking 100-200 feet from a grass fire or other outdoor burn ( used a controlled burn to test this ) it flips over and plants. Granted I am only using a KK board as I was not sure as to which way I was going for the fire dept UAV I am working on but I have experience flying all manner of RC helicopters and Planes over the past 20 years and to quote the neighbor who's burn pile we were testing with, That dog just wont hunt.
I don't want to risk the Thermal camera core until I get a stable platform. It is one thing risking a couple hundred dollars on a quad, But another risking $10k on a thermal camera.
If I cant get the multi rotors stable over fire ground then I think I may have to default back to a 700 Class single rotor.
All in all I am out a quad frame and 3 motors and props. I was building a cheap 550 class quad so I still have my KK the power distribution board and 4 12amp esc's so in theroy I could build another frame and get replacement motors and props to try it again.
Replies
This is what I think was happening, the burn caused an updraft of rapidly rising air and when the Quad crossed the threshold of this rising column of air the cool air rushing down caused a vortex that flipped the copter upside down causing it to accelerate towards the earth. I guess the only way to know for sure is to build another one and fly it under the same conditions.
I would guess that the quad heats up and the gyros begin to drift severely. A KK board will not compensate for that type of drift correction.
What you'll need to do is get a board with temperature compensation. A gyro like the one DIYDrones sell is adequate since the gyros have a thermo sensor inside. Then you'll need to do a very complicated thermal graph of the Gryo as you move it from room temperature to an oven. That graph can be fitted by an equation that represents the temp compensation.
I wish I could help you on the thermal compensation part. Perhaps Doug W. could go into more detail.
Jason
Weird. I would have thought that a proper flight controller board could handle that. Maybe the KK board is too simple?