Naza High speed oscillation on qav500 vid


B

Bella7821

Member
I have telemetry on mine and it seems if I go over 20mph sometimes I get the same. Maybe you going too fast. Who knows.
 

BorisS

BorisS

Drone Enthusiast
Hi Elliott,

i have the same issue with this setup :


Its a QAV500 with Naza and DJI ESCs, tried all different gains no chance to get rid of it.

I also have a TBS ESC32 Naza setup and I don't get the vibs at full speed. I suspect the ESCs on QAV500 DJI ESC are the problem so i switched to simonk flashed ones and i will be testing in the next couple days !

Boris

(Edit) by the way happens in both modes manual and attitude
 
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kloner

kloner

Aerial DP
rtryder had something like that to, think he did something with them 40mm motors tim sells that straightened it out
 


BorisS

BorisS

Drone Enthusiast
hmm it can actually only be a couple things, if i compare the TBS being fine at full throttle compared to the QAV500.



1. ESC are different, flashed vs DJI stock
2. Motors are different , axi vs. Tiger
3. Frame configuration is different, but qav500 should actually have netter flight characteristics.

At the beginning i thought its the qac500 bobins setup, that its not good for the gaza to be vibration isolated and that the clean frame plates on the qav500 delay the feedback to the gaza. But hard mounting the naza with some acrylic bridges also made no difference so the bobins are not the problem.

Boris
 

E

Elliott000

Member
interesting, Boris, let me know what you find out with the other esc's. In a few weeks this will have a cc3d in it but for now a speed limit of 20 or under is no fun lol

Edit, went out and flew tonight. I mad a throttle curve on 7 points but essentially its 0 30 50 70 95 that few clicks away from full rip made an improvement, ill try 90 max tomorrow it still flew well, never got in trouble with lack of power
 
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R

RTRyder

Merlin of Multirotors
Elliott000 said:
Hey guys after a couple flights I have come to ask for help. I get decent flight through most of the stick but if im above about 80 i get a high speed shimmy you will see in the video. Gains are 120 120 145 140 atti 85 85.
I cant get rid of it , 4s 5000 dji 30 opto esc's apc sf 10x 4.7
Thanks

http://www.youtube.com/watch?v=bt16Bl3DDZQ&feature=plcp
Click to expand...

Get rid of the APC SF props they are crap on the QAV, Graupner 10 x 5 are much better, I was never able to get decent flight quality with the S/F set I have. I did manage to get an acceptable level of stability using the 9 x 6 APC thin electric props with Avroto motors and 4S 5000 battery. This is video of the first FPV flights of my QAV with the Avrotos and Graupner props, I've had a chance to make significant improvements since. I've seen 50 mph on the OSD display with a tailwind and close to full throttle, stable and controllable but things come up in the goggle screens awfully fast! Normal cruising speed is right around 30mph and slow is low to mid 20's, with the new motors and Graupner props it will still hit over 40 mph with ease...


I was using 30A ESCs reflashed with SimonK firmware at the time, I've since swapped to a set of 30A HK Blue/Maytech ESCs with stock firmware as the reflashed ESCs seemed to be getting hotter than I was comfortable with being stuffed close together between the lower frame plates. I also swappped the motors over to a set of 40mm 620KV pancake motors which has slowed it down a bit and helped stabilize the flight even further. The other thing is the QAV/Naza combo is very sensitive to gain settings and the CoG. I have both basic pitch and roll plus ATTI pitch and roll TX adjustable as calm vs windy needs to have both reset to keep the QAV smooth. I find that basic gains usually run 100 to 110% and ATTI 50 to 70%.

Of course none of that helped this past Saturday when this happened, you can see a hard vibration develop just before the end, and indication that something bad is about to happen...


IMG_2497a.jpg


IMG_2499a.jpg


Not sure exactly what caused it other than it was a problem with the left front motor. I almost managed to save it, had it within 20 to 30 feet of the ground, level, and trying to get it down as quickly as I could while I still had control but whatever the problem it happened again and down it went. With the amount of damage to the arms, motors, wiring, and props I'll never know for sure what the problem was, I can only speculate and that serves no useful purpose.

I already have it back in the air with some interesting modifications that seem to make it fly even smoother, more on that later...

Ken
 
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kloner

kloner

Aerial DP
i really like the looks of the qav, but having aluminum arms doesn't even give you a chance to crash and fly.......... she got all kinds of stupid on ya bro. Sucks
 

kloner

kloner

Aerial DP
ken, is that 2.4 rc control or is it ezuhf with the antennas pointed off to the side? I used to get that but not sure what i changed that made it go away. it looks like that lockover they do but it looked like mine did when in rate mode with not enough throw to correct it. back then i flew 2.4 rc and i used to try balancing the props, and all it did was make vibrations that i'm 99% sure were what caused it. i had a guardian and ET osd too, and it did the same thing, the artificial horizon would lock over and sometimes take forever to straighten out back to the horizon. when i was there doing all that, i felt the gains were too high, but after watching movies over and over looking back, vibes.
 

R

RTRyder

Merlin of Multirotors
kloner said:
i really like the looks of the qav, but having aluminum arms doesn't even give you a chance to crash and fly.......... she got all kinds of stupid on ya bro. Sucks
Click to expand...

Yeah, I agree about the arms so I fixed that problem...

IMG_2500a.jpg


IMG_2501a.jpg


IMG_2502a.jpg


IMG_2503a.jpg


Amazing what can be accomplished with a little time and a milling machine ;)

Haven't had much opportunity to fly it other than in the backyard and the street in front of the house so far but it seems to actually fly better like this. I made it a tiny bit wider than it is with the aluminum arms so I can fit 11 inch props without clearance issues should I want to try that and I think the little bit of flex introduced by the new arms is just what it needed to eliminate the shimmy. It is possible to have a chassis that's too stiff, some amount of flex is a good thing at times, and I think with the alloy arms the entire lower section of the QAV is too stiff to fly well at all speeds.

Time will tell, I need to get over to the field and give it a good flogging with this setup, if it handles it OK I'll make a jig for machining the arms and make up a few spares for the inevitable "next time", I can swap all four of the plastic arms for less than the price of one alloy arm and the plastic might even survive minor crashes that would bend the alloy...

Ken
 


E

Elliott000

Member
RT pictures dont work? or is it me... I buried my qav two days ago.... too fast and i saw a street post a little to late hammered the throttle and hopped over it abut clipped a branch and blew a prop lol. I love this thing
 


R

RTRyder

Merlin of Multirotors
Elliott000 said:
Dood, pictures work now and I just happen to have like 9 arms downstairs lol. Is the " milling" do-able by hand?
Click to expand...

I'd have to say no, you need to have ability to measure and cut fairly precisely for this to work, otherwise you'll wind up with arms and motors that are out of alignment with the frame and each other. Not to say it isn't possible to do by hand but there's a lot of material that needs to be removed, holes to be drilled that are critical to alignment, and the surfaces have to be cut parallel to each other and to the motor mount as well.

I used a machinist vise bolted to the bed of the mill to hold the arm, not exactly the best method given the shape of the arms, and then did the same step on each arm before moving to the next cut that had to be made. No CNC, all done the old fashioned way, setup for each operation by hand with a lot of measuring. Even with all that they still aren't 100% perfect in every dimension but close enough that it flys at least as good as it did before the crash, I did it mainly to see if it could be done, what effect it would have on the way it flys, and to get it back to a flyable condition before the weekend.

If I were going to do more of these I'd make a jig that the arm could be bolted to for both repeatability of the cuts as well as shortening the required setup time. I've got repair parts ordered but to be able to fly over the upcoming long holiday weekend I had to do something now, by the time the parts arrive it will either be too late to tear it apart and swap parts or it will be after the holiday.

Ken
 


H

helifotos

Member
RTRyder said:
I'd have to say no, you need to have ability to measure and cut fairly precisely for this to work, otherwise you'll wind up with arms and motors that are out of alignment with the frame and each other. Not to say it isn't possible to do by hand but there's a lot of material that needs to be removed, holes to be drilled that are critical to alignment, and the surfaces have to be cut parallel to each other and to the motor mount as well.

I used a machinist vise bolted to the bed of the mill to hold the arm, not exactly the best method given the shape of the arms, and then did the same step on each arm before moving to the next cut that had to be made. No CNC, all done the old fashioned way, setup for each operation by hand with a lot of measuring. Even with all that they still aren't 100% perfect in every dimension but close enough that it flys at least as good as it did before the crash, I did it mainly to see if it could be done, what effect it would have on the way it flys, and to get it back to a flyable condition before the weekend.

If I were going to do more of these I'd make a jig that the arm could be bolted to for both repeatability of the cuts as well as shortening the required setup time. I've got repair parts ordered but to be able to fly over the upcoming long holiday weekend I had to do something now, by the time the parts arrive it will either be too late to tear it apart and swap parts or it will be after the holiday.

Ken
Click to expand...

Do you have pic of how the arm looks like after you finish it? in both end... before it whas mounted :)
ZoomButt.gif
 

E

Elliott000

Member
Finally flew this thing again, changed to my suppo 1000kv 2814'2 and 9" apc props. This multi ir retarded now lol, I get mad shakes after my last flight.... anyways, i might leave the panckakes off and run some expo on controls and find good gains for manual as this thing without being dialed yet is more amazing than it was before
 

kloner

kloner

Aerial DP
this one will want 8's if your under 2.5k...... on my disco i got em too...... but 8's minimized it and controlling how far forward you push it made it do it, not do it still....... the 2810's don't, but it's alot less power. like a totaly bone stock 450 with nothing on it,,,,,,, makes smoother flying, but man, sometimes the ground looks like it's comin all the way in the camera
 


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