ZYX short first impression and V-bar comparison

[Dr. M]

Originally Posted by RedOctobyr

Thanks for posting the file. But can you describe what you did to fix the tail?

Basically, I followed Mr. Mel's video. Set PI to 75-75 and dropped the main gain a bit. Then I increased the CW stop gain, which is B (not A like the manual states) turned on the optimizer and flew 4 packs. In the mean time I was also tuning the precomp.

[Dr. M]

One more run of the optimizer today. both cyclic and tail. By this point the VBar is flying pretty close to perfect. Paddle sim at 40 and Style at 90 for 2600 RPM HS; Style 50 for 2400 RPM HS. Sweet

I was flying in ridiculously high winds pushing 25kts. But it was fairly constant with little turbulence and no gusting. Also had an incident probably related to the wind where following an unloaded maneuver and a large HS overspeed at the end, when the governor caught up with my sudden collective increase against the wind, the OWB started slipping. About 60ft up 100ft away downwind and over salt water . All I could do was try to bring it back over dry land and with the last drop of HS, I dropped it in a soft pile of sand to the side. That made a mess, but at least everything stayed dry. I flew 2 more packs after that with no incident, but I guess my OWB is overdue for a replacement (about 300 flights)...

I'm trying to make a decision as to the comparison of the VBar and ZYX. I like the tunability of the VBar, the crisp collective, and precise cyclic feel. I also like the way ZYX flies and feels (firmware v4) and most of all I love the price. it's a tough one.

I was finally able to convince my wife to come along and shoot a video. We both soon realized that filming a heli is a lot more difficult than it looks. Here's a little compilation of one of the flights, where some of the out of frame or out of focus sections were cut out. Turn down the volume, the wind was pretty loud.

[ame]http://youtu.be/gKWmITocLFc[/ame]

[beenflying]

Great to see it flying so well, Dr.M. I'm glad it didn't end up in the salt water. It's been fun following your comparison. Thanks.

[Daddy]

Doc, you need to go see a Doc! Flying over water!!!! You might have a OWB fail or something

Those were some mighty smooth flying transitions

Best,
Ken

[Dr. M]

Thanks for the kind words guys.

[ZuvieleTeile]

Really nicely done and also congrats for the rescue of your Protos from my site.
For the next video, I think I have to send you my GoPro with headband . . .
No offense please to to your better half. I can imagine it was pretty difficult to video this in those conditions.

I did not make any progress in comparing the ZYX to the V-bar, because my beloved Logo-400SE is still on the shelf with a bent tail.
I was too busy installing another ZYX on a friend's old nitro 600 heli and setting it up.
And also busy with flying my TDR.
But that will change. I try to get my Logo fixed next week and will continue with the fine tuning of the Tarot.

I am really curious how a ZYX would work in my TDR, but I am afraid, that the back EMF and/or the overall power consumption would be too much for the bus bar of the ZYX.
I am logging constantly 4 to 8 Amps and 14 in peaks on the electronic side. . .

[Dr. M]

I think you'd need a separate power bus to put the ZYX on a big heli like that. The ZYX power bus gets power thru 2 servo connectors, which means it could probably handle 4A continuous, 6-8A peaks. I'd probably put the tail servo on separate power, and leave cyclic thru the ZYX.

[Dr. M]

After getting back home from my vacation, I decided to take the Protos apart and do some maintenance... partly to investigate the OWB slippage I wrote about above, but mostly to get the sand out of everywhere. I gotta tell you, greased spinning parts mixed with sand make a huge mess. Somehow sand got everywhere including inside the motor. This cleanup is gonna take a while - I wouldn't be surprised if I take apart the grips and I find sand inside the thrust bearings

[bgymr]

Loved this thread. Love my five zyx's even more now.

I fly them in everything from a 130x to my raptor 50. I just bought an X5 and a lot of people are trying to sway me towards the vbar. After reading this, I don't see the point. I have had different controllers, but I always go back to a zyx. I guess it's a comfort thing.

Great thread, thanks guys!

[Dr. M]

I've been meaning to post a final comment on this comparison, and keep getting interrupted by the analog life...

But, my advice is you should try a VBar if you can afford it and decide for yourself which one you like better.

[bgymr]

M, I appreciate your advice. In your comparison between the two units you go through some intricate details in each manuever of the difference. I can't even do the manuevers yet, so a vbar is more than what I need...for now. I just started doing aileron tictocs and inverted circuits on my 130 and 300. I do notice the tail dip in collective manuevers. But my helis are tuneable and are growing with me. Hopefully by the end of next summer I can justify flying a vbar.

Your sticky on how to tune a zyx have been invaluable for my tuning. Thank you!

[Dr. M]

I just bought a Robird G31 and will install it on the same Protos that flew ZYX and VBar. This will give me an opportunity to update this comparison with yet another FBL system

[Dr. M]

I completed the setup of the G31 on the Protos. It was pretty self-explanatory for the most part. This one does have a few quirks here and there, in particular the setup of servo limits is split between three different pages: one for individual servos, another for cyclic range and a third for cyclic ring. It could've been done better, IMO... OTT, it wasn't too bad, comparable in terms of time investment to the ZYX and VBar.

I've got some wiring to clean up, then wait for the weather to dry up for a test flight.

[beenflying]

Mushy collective feel and tail asymmetry problems saw my 3GY/G31 shelved. I tried everything with the heli to get it right, but in the end changing the G31 was the only thing that corrected the issues.

The mushy collective is like a collective pitch latency. Cyclic is fine, only the collective pitch is affected.

The tail was bounce in one direction. I replaced the entire tail, fitted a CF pushrod and changed the tail servo. Nothing worked but when I changed the gyro to a different brand, the heli flew perfectly again, as it had done before fitting the G31.

Personally I can't recommend this gyro for a 450 size heli. I hope you have more luck than I did, Dr. M...

[Dr. M]

So far the G31 seems to fly better than you describe on the Protos 500. The tail stops were pretty asymmetrical at first, but with a bit of tuning it's gotten much better. The collective feel around center is a bit odd, but much better than I remember it from my first go with these gyros.

[babyuh1]

I saw no difference in the collective between the G31 and the flybar. Maybe it's the servos?

[Dr. M]

Finally I got a chance to take the Protos (with G31) to the field for some proper throwing around. First thing I gotta say is the G31 handled the wind gusting 35mph quite well. I'm also impressed by the piro compensation, which is nearly perfect.

However, the feature that clearly stands out head and shoulders above all other FBL systems I've flown is the tail. I've never flown a smoother, more locked-in either FB or FBL. No only does the tail just sit there and does not move without command, but also is loads smoothly and progressively in aggressive maneuvers. This can easily be observed in fast nose-down right-rudder funnels, which are extremely taxing on the tail rotor and most gyros make the tail scream as you push the speed higher and higher. In contrast, he G31 appears to load up the tail rotor much more smoothly and the sound it makes is at least one octave lower. Unlike the ZYX and VBar, it also required very little tuning and fiddling to get the stops clean and symmetric and good behavior throughout the flight envelope.

Now to the less than stellar parts than require further tuning... The cyclic has a slightly vague, disconnected, and non-linear feel, as if fighting small inputs around center, then all of a sudden overcompensating and going too fast. This may be an issue with the on-board "expo", which I'll set to 0 next time I fly to see if it fixes this issue. In any case, I felt as if I was running a few milliseconds behind the heli the whole time I was flying and just could not get it into the groove. I'll also experiment with increasing the "Agility" parameter which appears to be a sort of Feed Forward mechanism.

[Daddy]

Sounds neat. Don't forget to give us opinion on the vib software That is what has interested me on the unit...I almost bought one and may still. But watching the market atm as competition is getting pretty wide. I expect this spring will bring a few more additions.

Hope the expo does it, that'd be easy

Cheers,
Ken

[Dr. M]

Originally Posted by Daddy

Sounds neat. Don't forget to give us opinion on the vib software That is what has interested me on the unit...I almost bought one and may still. But watching the market atm as competition is getting pretty wide. I expect this spring will bring a few more additions.

Hope the expo does it, that'd be easy

Cheers,
Ken

Vibration logging is awesome. So much better than the live-only view available on VBar. That is, if you have a heli with vibes... I always knew my Protos is a smooth machine, but this is the first time I have confirmation with hard numbers. The vibe log barely shows anything above baseline. In fact, the G31 can't even see the tail RPM, it only records some minor peaks in lower harmonics from the tail at 1/2 the RPM. I'll post a picture later.

I do think the vibe log would be very useful in diagnosing problems, such as those occurring after a crash.