Have constructed an enclosed ‘H’ frame carbon/Kevlar quad with soft mount front and rear arms for vibration reduction. Initially yaw was awful as the arms tilted in the wrong direction and opposed any motor torque so I had to stiffen the mounts to prevent yaw reversal. Now I have reversed the motors in the code and the tilt actually helps the yaw. The mounts on the video are very soft, just to help demonstrate the movement but I think they were bottoming out.
Am quite pleased with the lack of vibration showing on the camera.
Apart from the motor reverse all parameters are completely stock. Will tweak them when I get some time.
Vince
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One other advantage of this frame is there is a front and back. I dont know how guys keep orientation on an x frame at distance. Guess I’m old fashioned but I feel a lot more confident with it, just like an RC heli.
Leonard, Im thinking of a foam cored carbon ‘plank’, lowered in the middle like (side profile) ----____---- Then a non structural carbon shell. I didn’t like the lack of access to the end sections. The soft mounts would be up the other way so if one lets go it would bottom out on the frame.
Max, some info on my motor setup, good and bad.
http://diydrones.com/forum/topics/530kv-4008-motors-with-large-prop...
Looking good !!!
What motors and props ?
Cool, I am interested to see the result.
I was thinking of doing a full fuselage using some of the techniques we use to build high performance gliders. I was thinking of having a removable nose cone so that a tray can slide down the middle. It will be a while before I can put it into action though.
Thanks for sharing!!!
The single layer kevlar shell was very floppy on its own. I was hoping to have the carbon battery floor removable but to give sufficient tortional strength it needed gluing. Now it is absoultly rigid end to end but makes it a bit fiddley to install stuff. Now I know it works I will loose some ali from the brackets.
Mk II is forming in my head.
I suspect that you are correct. It depends on the geometry of the frame but some copters may flex the other way too. This is very interesting :)
I have been thinking about a similar concept as your fuselage. How flexible is the central fuselage?
can you publish some pictures from the mount?
To turn the quad, one motor on each arm will speed up and the other one will slow down. This uneven lift causes it to tilt. The one behind the camera is of course doing the opposite.
It might not look like much ‘vectoring’ but when it was in the wrong direction it was overcoming the normal yaw control, so I guess it is at least doubling the yaw effect.
The motors are not very big, just low Kv – 530, so turn much slower than normal so you need bigger props for the same lift. Its quite efficient, hovering at 14A – not bad for 2.1kg. The video is from a gopro in the case so its a bit muffled. I have one from another camera and it sounds like a Lancaster bomber.
This tilt effect is only noticeable with yaw, (and is exaggerated in the vid because I used extra soft mounts). It seems firm in roll and pitch. Hopefully I will get some tuning and flying done today (but its very windy).
Thanks for the pointers Leonard. I suspect most quads flex a bit and some may see better yaw rates with reversed motors. I may try and get a vibe reading today.
LOL, very nice job. Glad you got the code working. I think this is very cool :)
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