I did some more flights on the weekend to test out my branch of Arducopter 3.0.1 -THdev and wanted to show what it's like from on-board the heli in a reasonably high-speed run. This run used 12 waypoints to form a rectangular pattern with rounded corners around the flying field, trying to achieve a nice smooth flight path. I still haven't been completely successful as it's a bit jerky. This was using WP Acceleration of 200 cm/s/s, and WP Speed of 25 m/s, but this was not achieved on this flight. It did hit 20 m/s, and I'm happy to see that it's very very smooth. With settings of 20 m/s and 100 cm/s/s acceleration it's much smoother but takes too much room to accelerate. This was also using the Yaw Look Ahead mode which causes the yaw to automatically look into the direction of flight. The flight ends with an RTL which causes the yaw to return to the original orientation on the final descent.
Overall, I'm very happy with the performance, but I really anxiously await the Spline Nav feature! :)
The heli itself is still a work in progress. Obviously the camera vibration damping is completely unacceptable and I'm redesigning that. But other than that, it's going well. The Direct Drive Tail is brilliant, and really simplifies the mechanics.
I am getting about 12 minutes flight time, including a 3 lb payload (yes, I'm using steel blocks as ballast), and this is with a battery load smaller than a 700 typically has. Normally they run 12S 5000 mAh, and I've only got 8S 5000 right now. But I plan to run a total of 8S 10,000 which should give better than 20 minute flight times.
Once I'm comfortable with the reliability, I'll be stretching it's legs on longer runs. I'd like to have this capable of at least 100 km/h flight with a camera on-board. What I envisage building is a compact high-speed aerial filming platform capable of chasing race cars, etc. Ultimately I will build a completely custom frame but for now I'm just hacking on this 550 frame stretched to 700.
Comments
The LPF is something that is now running in the code by default. The parameter is something like MPU_6K_LPF or something like that. It should default to 20Hz, but you could try 10Hz.
I couldn't get this "lowpass filter ".
Can you elaborate it a more plz.
And that's what I had in mind, I'll do the same and will farword you my logs for vibration analysis.
On the gasser, I would start out by designing a vibration mounting system, and mount it on the heli but do not put it in control. Test it out while recording vibration logs. Then analyse the logs to see if they look good. Only then would I put the APM in control.
That being said, using the lowpass filter has completely transformed the vibration performance. So this should be possible.
I've got a AirStar Mongoose with a 26cc 2-stroke gas engine that I've been eyeing ;)
For now, going to tune my 450 heli with APM
No, not that I know of. It would be really great to see if it's possible. That would really open up TradHeli to some amazing flight times and ranges.
I've got a weed trimmer with a nice lightweight 4-stroke gas engine that I've been eyeing....
Great Job Robert!
Good to see someone working on TradHeli. have anyone tried this on gasser ?
i mean something large gasser like 26cc ?
Phil, good question, and I don't have a great answer. Technically, these aren't "hobby king servos", they are manufactured by Lontair, and just have an HK sticker. So the real question is, are Lontair servos good enough?
I've been using them for about 2 years now, and they've been good. I did just have a tail servo burn out, but I believe that is due to running gains too high. This can happen to ANY servo, even a Futaba.
Sometimes I wonder if I'd be better off spending the money on Futaba servos. But they are a LOT of money. I'd be spending 4 times as much, and I just don't see much benefit. I've taken several of these apart, and from what I can see they are well made. I've crashed these many times while developing the program, and only ever stripped out one. Otherwise, they are fast, strong, center well and have low deadband.
These Lontair servos are magnetic induction, meaning no potentiometer to fail. I believe in the technology, and would wager even Futaba will move to it in the future, it just makes sense. I'm replacing the burnt tail servo with a Lontair MI Brushless servo. I'd be looking at almost $200 for a comparable Futaba servo, so $800 in servos on this thing... I dunno.
And Futaba is the ONLY servo manufacturer I would trust on reputation alone. I have no reason to believe anybody else is making better servos at any price.
Awesome work! Can I come see the heli's? :)
Yeah, the wiring... I'd like to have it all invisible internally... I used to spend ages doing that, but I just don't have the time anymore, and there's SO MUCH wiring now.
Yep, two speed controllers running Gov. The tail rotor uses 65W in neutral thrust, and about 400W at full thrust. Actually, full thrust probably draws less than that, as I believe the blades stall out somewhere before that and then stop producing as much thrust.
Yes, the tail motor makes it tail heavy, but I actually want it that way. I want as much weight up front as possible, so the batteries can be on the vibration damping platform with the camera. I don't see any good coming out keeping the tail light, and then mounting the batteries on the boom, as most camera ships do.
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