Hoverfly Crash - Need help figuring out why

[eddarack]

I've been flying my recently-completed Y6 a bit. I had everything trimmed out where it was very smooth flying with auto-level enabled. I took it up to about twenty feet and enabled position hold (GPS showed green, a good fix). It stayed in place, and made a slow counter-clockwise circle with a radius of about ten feet. When it completed its circle, it flipped and came crashing down. Thankfully, the frame is just slightly broken, and everything still works. Auto level was enabled, and I had it in position hold mode. I was not making any control inputs. Would the altitude hold gain have anything to do with this? Here is a video, taken from the Y6, when it happened:
http://www.youtube.com/watch?v=Ny8swpUIm2A

Also, I had just put in a fresh battery. Not sure if that may have had something to do with it. I think I may have heard the power drop, but not too sure.
Thanks in advance.
Here it is before it tumbled to the ground...
View attachment 12244

 

[Aerovideo]

Sorry to see your crash. I have no idea if this would be the problem but I fought with a bad connection with a bullet connector between an ESC and motor. I finally just soldered the motors to the escs and never had that problem again. It can be tough to diagnose as it's intermittent. Since it's a Y6 I would think it would have been okay if you lost one motor. Maybe a problem with your power distribution? I've lost one motor on my Y6 and was able to recover and land.

One last thought, do you have the Green or Black Hoverfly Pro board? Some of the earlier green ones needed a power filter. Sometimes the board would reset with dirty power. If you have a newer Black board then this isn't the problem.

You might also fill out a ticket and include your flight log from the GPS SD card, maybe the HF guys can determine from that why it flipped.

 

[eddarack]

Thank you, Paul. I was wondering if it may have been a power issue. I was very careful about soldering, connectors, and insulators (it's a carbon fiber frame) and I'm confident that it isn't a problem with electrical connections, although I am not entirely certain. I have the black board, and also I have the DPCAV filter, just to be sure. I did the throttle calibration as per Hoverfly instructions. I was hoping that this might have been an altitude hold gain issue, but it is sounding like maybe it is something different.
Thanks again for your input,
Best
Ed

 

[Stacky]

Hi Ed, Pauls advice is great, do a support ticket via this link https://hoverflytech.zendesk.com/anonymous_requests/new and also visit this page https://hoverflytech.zendesk.com/home and see if there are any tips in there. I dont have the GPS board so cant help with that sorry. I do hear what sounds to me to be like the gains may be a little high with the squirrelly sound but I doubt that would be the problem. With a sudden drop in power like you had it could be a number of things. Solder connections would be the first look but it sounds like you had that covered. Another possibility could be esc setting, if you have them set to Lipo they will cut off once the voltage drops too low so need to be set to nicam. Also a possible faulty esc might cause that sort of thing. Check how well your board is isolated from vibration as well although looking at your footage its jello free so you probably have the ok as well.
Best bet though is to send in a ticket and if possible download the flight log and send that in.

Cheers
Mike

 

[eddarack]

Thanks, Mike. I'll do that.
Best,
Ed

 

[Stacky]

Ed if you dont hear back from HF within a reasonable time let us know back here. Also I just had a peek at a couple of your videos and I can hear right from liftoff a glitching or squirrelly nose in the flight sound. Paul if you can have a look and see what you think?. Something doesnt sound right to me, gains or something else?

Cheers
Mike

 

[Bartman]

which ESC's did you use?

 

[JZSlenker]

There is no AH gain anymore in the newest firmware. It's either on or off.

 

[eddarack]

I have version 4.8. I'm not looking at it now, but I seem to remember seeing a gain setting on altitude.
I'm using Turnigy plush 25 amp ESCs.
Mike,
Thank you! By memory, I seem to remember that in the Hoverfly software interface, with the control board plugged in and the board powered, It shows that main gain is 37, and the altitude gain is 47. My Y6 is relatively small, the prop hubs are 14 inches from the center of the body. Might the gain be too high? Or does size not really have much to do with gain...seem to remember that it does.
Thank you in advance for your help.
Best,
Ed

 

[eddarack]

Hi Ed, Pauls advice is great, do a support ticket via this link https://hoverflytech.zendesk.com/anonymous_requests/new and also visit this page https://hoverflytech.zendesk.com/home and see if there are any tips in there. I dont have the GPS board so cant help with that sorry. I do hear what sounds to me to be like the gains may be a little high with the squirrelly sound but I doubt that would be the problem. With a sudden drop in power like you had it could be a number of things. Solder connections would be the first look but it sounds like you had that covered. Another possibility could be esc setting, if you have them set to Lipo they will cut off once the voltage drops too low so need to be set to nicam. Also a possible faulty esc might cause that sort of thing. Check how well your board is isolated from vibration as well although looking at your footage its jello free so you probably have the ok as well.
Best bet though is to send in a ticket and if possible download the flight log and send that in.

Cheers
Mike

Thank you, Mike. So you think it was a drop in power? Looking back over the video I can't tell for sure. I'm confident in the solder connections - I paid a lot of attention to this during the build process. Of course, I'm relatively new to this, but did pay close attention. I programmed the ESCs exactly as Hoverfly outlined, using the NiCad setting. I went to extra lengths to isolate the board from vibration, using sorbothane where the nylon bolts mount onto the frame, so the stacked boards are "suspended" so to speak in this very effective vibration dampening material (which the manufacturer claims to be the best in the world). Will send in a ticket to Hoverfly. I have to figure that process out next...
Thank you again for your time and input,
Best,
Ed

 

[Webheadfred]

You know, I'm no expert but I still get weird anomalies when using PH. Nine times out of ten, it's perfect. Then just when i get comfortable with it, it tilts 45º and races off to never never land. I'm ready for it now. There may be nothing wrong. It could be one of those GPS anomalies; which of course, doesn't help. See what HoverFly says about your log if they answer. They never responded to my Zendesk request so I'm rooting for you.

 

[Bartman]

turnigy Plush 25A......


what motors and what's the weight of the heli ready to fly?

i ask because the HF PRO doesn't love to talk to stressed out ESC's. If they're getting hot and start to speak gibberish with the PRO, the PRO bugs out. For example, using 30A Turnigy Plush with Tiger 2814 motors the ESC's were getting hot and one of them was browning out keeping the PRO from continuing its juggling act. Switching to 40A ESC's eliminated the problem, PRO was happy again.

just a thought.

@Fred, the GPS seems to work really well but then will freak once in a while...i don't understand it either but the return home works well and the carefree mode works really well with a clean mag reading. i finally tried it the other day and was pretty impressed.

 

[Webheadfred]

I haven't tried the carefree mode yet. I'm not sure I really understand it. I've become pretty good at nose-in flying but I'm sure that carefree mode could help a fella out at times.

I agree with the GPS. I like it. I trust it. Kinda. The RTH does indeed work nicely.

 

[Stacky]

Ed, I dont know if it was a power issue.
Have you tried flying it without the GPS board attached?. Its one of those faults where the process of eliminating things might help.
The only thing I do know is the squirrelly sound that your multi is making doesnt sound right to me.

 

[eddarack]

Thanks, Stacky.
Do you think that this is because the gain setting is too high? When it lifts off and is in ground effect, it oscillates on all axes, not a lot, but a bit. I think that this may be it. Once I put it back together I can try flying with the HFP board only.
Thanks again,
Best,
Ed

 

[Stacky]

I think you should just try adjusting your gains to see how the multi sounds. Put in a fresh battery. Lift off and hover at about 5 or 6 feet up. Wiggle the sticks gently and listen to the motors. The way they are now gives a sort of squirrelly sound. If you can hear it land and lower your main gain on your radio in increments of 5. take off, hover, listen and then do a gentle stick wiggle and see if the sound has changed. If not lower the gains by another 5 and see how it sounds again.
As you lower the gains your multi should start to feel a bit looser each time, if you increase them it will start to feel twitchy. You want the point where the twitchyness goes away. It shouldnt take long, with the HFP its a short easy task, maybe 4 or 5 lift off and landings at the most.

 

[octocine]

From the twitching in the video it does seem that the gain is too high. A friend kept upping the game to on his and it eventually caused a flip. I've had a similar flip and crash that I eventually attributed to a loose wire going into the board. Good luck!

 

[eddarack]

OK, thank you all! Once I have it back together I'll adjust the gain settings down and see what happens.
Best,
Ed

 

[eddarack]

So I hooked up my board to the setup client, and checked gain values:
With Autoleveling OFF, main gain reads 47
With Autoleveling ON, main gain reads 37
With Altitude Hold Enabled, Altitude Gain is 24
With Altitude Hold OFF, Altitude gain is 5
With Autoleveling Off, and Position hold enabled, main gain reads 47
When it crashed, Autoleveling was on and position hold was on.
What is the danger of very low gain settings? Not as responsive? I'm just looking for a smooth, easy-going performance profile, nothing fancy. It does seem, from what I have read here and other places, that my gain settings are too high. The craft weighs about 5 pounds, the rotor hubs are 14 inches from the center of the craft. I've balanced the craft so that the center of mass is where the three arms meet. I've checked and re-checked power connectors, etc. and everything looks fine. There are no loose wires, and no carbon fiber dust to flakes on anything to cause a short. The ESCs are all calibrated as per Hoverfly manual. I'm pretty sure this is a gain issue (when I launch it, it oscillates at a pretty high frequency in all three axes). Should I drop main gain and altitude gain values by 10? or more?
Some more info: I'm using these motors:
http://www.gravesrc.com/BP_A2212_10_Brushless_Outrunner_Motor_p/bpa2212-10.htm
With APC slo fly 10 by 4.7 props
With Turnigy Plush 25 Amp ESCs.
I have the black board and also use the DPCAV power filter.
Here is the crash video:
http://www.youtube.com/watch?v=Ny8swpUIm2A
(you'll have to turn the volume way up to hear the motors)
Here is a video of it launching, but with AutoLevel OFF. (I usually launch it with it on).
http://www.youtube.com/watch?v=30Hewfe9zKM
And here is an in-flight video:
http://www.youtube.com/watch?v=DgbRFuW9ixs
Thanks to all the experts out there in advance.
Best,
Ed

 

[Photo Elevate]

If you are using the latest firmware. There is no gain adjustment for Altitude Hold. You can return your switch values to their default settings. The Altitude Hold feature no longer needs to be tuned. https://hoverflytech.zendesk.com/entries/23296187-PRO-GPS-Firmware-Update-v4-8

Your main gain values may be set too high hence the oscilations. Also the same gain value should be used in autolevel and normal flight.

Hope this helps

Hoverfly really needs to completly rewrite the manual. There is so much conflicting information dotted about on the website and forums.
It is difficult for someone new who has not followed the process from day one,to find the correct information and this could spoil thier Hoverfly experiance.