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Helis and fixed wing

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Wednesday, June 20, 2012

Tarot ZYX 3 Axis Stabilization System: And Update

A while back I bought the Tarot ZYX Stabilization System and a FBL (flybarless) two blade head for my Frankenheli 450, as a less expensive alternative to the BeastX, which I have installed on my EXI 450. I bought a cheap aluminum head instead of the quality Tarot head, which I may get if I keep this system. I installed it today. Couldn't get it apart... I will likely replace it soon.
The BeastX is a magnificent system and is my stablization system of choice. It is well designed, easily programmed and works. The computer link is weak however, and allows updating of software on the device and limited parameter programming, but not programming of the device. This is fine as the button/sticks programming system, much like using an Align Gyro programming, is very easy to do.
The Tarot is a mixed bag... My first one failed outright, the set button caved in; sent it back and got a replacement. I decided to get the USB cable with the replacement gyro sent to me by the vendor, but I had no idea how it worked. The USB device is a simple cable with a dongle, but no software, no manual. The manual doesn't even mention the dongle, let alone how to use it. There is no software made by Tarot that I can tell. I installed the first software I found, which had a driver exe file I used, but uninstalled it when I found a better one, below. This first one here has the driver. I ended up using the one that seemed to show up in all the vids, and that looked like it had access to all the programming functions. I used this one. I didn't have instructions on it (they are available on his site) but it was pretty striaghtforward.
I connected the USB dongle to my notebook, and the ZYX gyro. Powered up the heli and set the rudder stick over as the gyro initialized, putting it into setup mode as described in the manual. The assigned COM slot showed up on the software and I clicked Connect. I selected F3C, and then clicked Setup. I walked through each tab one by one. It covers all of the programming steps on concsecutive tabs. I had problems getting the device and servos to respond to the inputs on the notebook consistently. I couldn't center the servos on the trim page, and it took a couple of tries to get the pitch, elevator and aileron ranges set. All the other tabs worked fine, but if servos had to move it wasn't consistent. I found if I reset the connections (started over) and went directly to the desired tab it increased the likelihood of response, but I never got the subtrim to work All in all it beat the hell out of following flashes and moving the transmitter sticks. In the process I failed to set the "gimbal" gyro settings on the next to last tab... When I tilted the heli the swash didn't move at all... I wasn't sure about that. I took the heli out and spun her up. I lifted off and BAM! I saw what happens when the gimbal setting is backward. The heli tiled left and when the gyro saw that it rolled hard left, instead of right to compensate. That's how I realised I failed to complete that setup tab...
Went back and set up the gimbal, and it compensates perfectly. It was set up backwards. I had to balance a new set of tail blades, and tomorrow I will have to change out the main shaft (slightly bent, sets up a vibration I can get rid of). I have a feeling its going to work out just fine. Tomorrow I will let you know!
UPDATE (6/21/12): This morning I changed out the shaft, though it wasn't bent much at all. I set her up with new blades, and took her out to the driveway. This time she lifted off and yawed left, but was otherwise stable. She did this depsite my compensating, a slow spin. I checked her out and while she has right rudder, the tail blades don't move all the way over, which I knew. I made sure the gyro was compensating in the right direction (pinch test). This tail ROM issues was one of those programming steps I could not get to reliably respond to programming inputs. I took her back to the lab and thought I would try the manual transmitter programming. I startd the process and held the stick over to enter the programming mode. Now before I misunderstood the instructions about the light sequence to know she entered programming mode. This time I held the stick over for a lot longer, then saw the cascade of the three lights that indicated she was in programming mode. I tried getting to the section of programming where I set up her tail range of motion and it worked one way, but stopped half way over to the other... So I abandoned the programming mode and decided to try going to that tab using the USB link. I thought that since I had not waited for the cascade of lights indicating programming mode before, maybe if I did the servos would respond. Well, here's where I learned that if you go into programming mode with the USB, the USB will not connect to the gyro. Okay... so I restarted and didn't hold anything over, and she connected. I went to the tail and set both ranges to max, as when moving it the tail didn't respond so I had no way of knowing wht to set (the servo not responding to programming thingy). I exited and now have full range of motion in the tail. This time she had a vibration at certain RPMs which I think I have calmed down a bit, but the yaw issue was gone, no idea what or why. I found I had to stabilize the CF tail pushrod as it vibrated and bent like a guitar string, using some supports I had in stock. The tail just didn't have enough ROM, problem solved. I kinda got the impression she didn't have much headspeed, and did I notice a two step approach to high RPMs? Problem for another day, though I reprogrammed the ESC.
So, I know she hovers, will let you know how she flies when I can get her to the field. I and rather optimistic!
I guess I could have squared the swash for the pic...

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