Problem with NAZA-H

[Valkman]

That is one very well setup heli well done. Any chance of seeing a video of it in GPS at about 100 feet!

[FPVflyer]

I'm uploading the video of the first LR flight, where are some GPS ATTI moments 2km away...

[Valkman]

Did you get that video up?

[FPVflyer]

Yes it is, but isn't really cool 'cause I wasted a lot of energy to get confidence, tomorrow will do more 2-3 flights, and it should be fantastic weather, so wil post a new one with the videos of tomorrow

[Aaron Hartwell]

FPV, I've spent all day messning around with my Naza H. I was hitting the exact same thing you were hitting - swash was way off level on start-up, swash didn't respond to stick movements as you'd expect, heli couldn't lift off due to crazy swash angle and Naza wouldn't correct as the heli started to tip.

I reflashed the Naza (1.2 ->1.2) and things seem to be working better. I'm going to hover it tomorrow to see what happens. Did you ever figure out what you did to get things working?

In case others, Naza folks included, read these threads it be nice if your videos of the Naza behaving strangely were still available. Clicking on the links in this thread results in a message that says they've been deleted.

[FPVflyer]

Ok peoples, an interesting video here:

https://vimeo.com/56315863
pass: rex600

Aaron, about your problem, finally I didn't understood why it has done this error, and also why he fixed himself

The only thing that I really know, is that I've done much than 20 flights and all is ever gone as well, in warm (15°C) and cold (-3°C) temperature, altitude and other conditions, the problem has never been presented anymore.

[mhoebrec]

Originally Posted by FPVflyer

Ok peoples, an interesting video here:

https://vimeo.com/56315863
pass: rex600

Aaron, about your problem, finally I didn't understood why it has done this error, and also why he fixed himself

The only thing that I really know, is that I've done much than 20 flights and all is ever gone as well, in warm (15°C) and cold (-3°C) temperature, altitude and other conditions, the problem has never been presented anymore.

Impressive

[Aaron Hartwell]

Originally Posted by FPVflyer

Ok peoples, an interesting video here:

Aaron, about your problem, finally I didn't understood why it has done this error, and also why he fixed himself

The only thing that I really know, is that I've done much than 20 flights and all is ever gone as well, in warm (15°C) and cold (-3°C) temperature, altitude and other conditions, the problem has never been presented anymore.

Like you, problems that suddenly go away with no rhyme or reason worry me. I'm looking forward to putting her through some hovering this morning.

On a seperate note, I'm going to PM you about FPV stuff. I fly long distance planes. My standard set-up is 2.4 ghz lawmate vtx/rx, 14 dbi patch, linear polarized vtx antenna, security cam 2000 cams, Tiny OSD, rangelink UHF 533 mhz control. I'm curious to see what you're using on your heli.

[Valkman]

Originally Posted by FPVflyer

Ok peoples, an interesting video here:

https://vimeo.com/56315863
pass: rex600

Aaron, about your problem, finally I didn't understood why it has done this error, and also why he fixed himself

The only thing that I really know, is that I've done much than 20 flights and all is ever gone as well, in warm (15°C) and cold (-3°C) temperature, altitude and other conditions, the problem has never been presented anymore.

Wow!

[R_Lefebvre]

That's pretty cool. Those (failsafe???) motor shut-downs are weird though. I thought in failsafe it's supposed to keep the motor running?

[NexxuSix]

Originally Posted by FPVflyer

Ok peoples, an interesting video here:

https://vimeo.com/56315863
pass: rex600

Aaron, about your problem, finally I didn't understood why it has done this error, and also why he fixed himself

The only thing that I really know, is that I've done much than 20 flights and all is ever gone as well, in warm (15°C) and cold (-3°C) temperature, altitude and other conditions, the problem has never been presented anymore.

Awesome, and beautiful!!! The failsafes look a little scary... I hope that isn't a pending failure in the system. The VNE was a bit crazy too. Glad you regained control!!

Thank you for the video!!!

[R_Lefebvre]

What's the deal with the VNE? I thought that you are supposed to lose roll control as the retreating blade stalls. But that was a pitch oscillation.

Is that what actually happens? Very important for me to know, as I am fighting a similar phenomenon. I thought it was a problem with the pitch controller, but maybe I'm just going too fast?

[StraightUp]

Amazing video FPVflyer. Thank you. I hope to fly fpv like that some day, but for now I still need to get my Naza H set up, if the weather cooperates will maiden today... kinda scared since I have only flown flybar (aside from my Mcpx) and this Trex 550 is flybarless, so two firsts, first test with Naza H and first test with this FBL heli....fingers crossed.

As for FPV that is my ultimate goal, to be able to explore like in your video

[zeeflyboy]

it's not technically VNE, it's only VNE for his settings as they are on the Naza.

As you know the faster you go the more the heli "wants" to nose up due to increased lift on the forward going blade when perpendicular to the airflow (and indeed reduced lift on the down wind blade) which gets translated 90 degrees through gyroscopic precession to then act as a force lifting the front of the disc.

This is something you sometimes see on FBL controllers when the controller can't appear to cope any more with this and it starts to do a good dolphin impression as it fights to lower the nose.

it's also why you don't see it in aileron, only in elevator.

The beast X is the only FBL controller I have used which actually has a setting specifically for reducing this nose up effect, others allow you to tune it through more complicated sounding and varied parameters. If you had the dial too low on the Beast it'd just nose up during fast flight, too high and it'd do the dolphin.

I would expect if he lowered the elevator gain he could go faster still, but slow flight may be affected.

[StraightUp]

Two things regarding FPVflyer's video:

1) Regarding failsafe, I tested mine on the bench, blades off and in manual mode when failsafe kicks in the motor powers down (just the way I set my failsafe up), but in atti or GPS atti mode it keeps the motor powered at the same setting it was in when I switched off the radio. So were you flying in manual mode when these failsafes happened or in gps/atti mode?


2) Regarding VNE I remember reading that you were using Spinblades (Asymetrical) which have much more lift could this cause VNE at lower speed?m

Cheers,

G

[R_Lefebvre]

Thanks for the info! That is exactly what I'm dealing with! I kid you not, I've been explaining it to the other devs as "porpoising", or like a boat out of trim. Sounds exactly like a dolphin.

Yeah, the more pitch gain I give it, the worst it gets, but if I lower the gain too low, I lose control. It's also being effected my the Z-axis (altitude) controller. The more gain I put in, the worst it gets. It's like I need a heavy damper on these as the speed climbs maybe.

Any controls experts have any ideas???

I looked at my data logs, and apparently I've been pushing this 450 up to 70-100 km/h, with a slightly low headspeed, which would drop the VNE even lower.

The Darkhorse calculator shows the Vmax at 110 km/h, but I'm not sure if that's the same as VNE or what they're doing.

Originally Posted by zeeflyboy

it's not technically VNE, it's only VNE for his settings as they are on the Naza.

As you know the faster you go the more the heli "wants" to nose up due to increased lift on the forward going blade when perpendicular to the airflow (and indeed reduced lift on the down wind blade) which gets translated 90 degrees through gyroscopic precession to then act as a force lifting the front of the disc.

This is something you sometimes see on FBL controllers when the controller can't appear to cope any more with this and it starts to do a good dolphin impression as it fights to lower the nose.

it's also why you don't see it in aileron, only in elevator.

The beast X is the only FBL controller I have used which actually has a setting specifically for reducing this nose up effect, others allow you to tune it through more complicated sounding and varied parameters. If you had the dial too low on the Beast it'd just nose up during fast flight, too high and it'd do the dolphin.

I would expect if he lowered the elevator gain he could go faster still, but slow flight may be affected.

[zeeflyboy]

Well VNE is tecnically an airframe limitation, the speed a to which buffeting will start to occur due to retreating blade stall.

I honestly don't think that is what you are seeing here, but one way to test would be to increase the head speed. If the problem still occurs at the same speed (or slower) then you know it can't be retreating blade stall.... if it occurs at a higher speed then either it is retreating blade stall or something else is happening regarding gain.

It might be an idea to pop in on the guys that do speed runs with banshee's and TDR's etc - they'll be much more used to the tuning of FBL units for high speed passes.

One thing that springs to mind though - you have GPS on board which most don't. You could dynamically alter your pitch gain with speed (okay so it's not airspeed but it'd be close enough I'm sure).

[R_Lefebvre]

Yeah, I'm not convinced it's VNE either. Mainly because I cannot get it to do it flying in Stabilize mode. Stabilize mode means we have Stabilization on the Pitch/Roll, but manual collective control. Alt_Hold mode means the same controller on Pitch/Roll, but automatic control of the collective.

So in Stab, doesn't do it. In Alt_Hold, it does. So it's either the altitude controller doing it, or a combination of an interaction between the altitude controller and the pitch controller.

It may be something like VNE which sets off the interaction, but the controllers are making it worse. I gotta solve it because if it starts porpoising, and then you bank to turn, it starts doing it in roll which gets ugly fast, and once that starts, it also crosses over into yaw. I basically have to release all the sticks and let it settle down.

Yes, I have thought about using the GPS velocity to reduce the gain automatically. That wouldn't be too hard. Yes, groundspeed /= airspeed, but it's the best we've got unless I put an airspeed probe on this thing, which I could do but... ugh...

Which controllers do really well with this? Beastx? Any others?

[FPVflyer]

Hi peoples,
I'm glad that my small video opened the questions in all the minds

About the FS, at the begin I followed the suggestion of Zee, and set it up into the NAZA, so when the RC signal get lost, the mode control of the NAZA go in FS, like it should to be, but it's very dangerous, 'cause it simply turn off the motor. So now I set the RC control which manually switch the mode in GPS ATTI when RC signal get lost, I tried it in the air, and 10'0% success!

So it's much safe.

About the VNE, I wrote VNE in the video 'cause I was thinking it was, but reading what Zee say, I'm pretty sure he's right, it's a limitation of the NAZA.

Today I've installed the upgrade of KDE, tail control, it's much better than the original, I added a ring more to take out a small empty space and it's working as well. Ever today, I tried 1 flight with Gopro Hero3 black installed, in a sandwich of silicone and sunning 2,7K 30fps... Man, this cam is awesome! I'm editing it right now, will post this week pass protected just for this thread

[zeeflyboy]

That's really odd about the failsafe but it does correlate with what someone else was saying - when it goes into failsafe from flying around in GPS or Atti it works fine, but from manual it appears to cut the throttle.

It must be a bug causing that... I would expect most won't have noticed it since most won't be pushing it into failsafe.

Could anyone else just test by backing the motor away from the main gear and then turning off the transmitter to force failsafe mode, testing turning to failsafe from both from manual and from GPS Atti/Atti to see what happens to the motor in each?

If this is a bug it's a big one!