VCTRC 3GX Flybarless 3-Axis Gyro - Page 6 - RC Groups
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Nov 25, 2012, 09:14 AM
Zippy Puffer
2Doggs's Avatar


Quite surprised to see it mounted on what looks to be a fairly flexible and thick piece of foam. Wonder how that compares to something stiffer, such as 3M tape?
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Nov 25, 2012, 10:18 AM
Not da momma!
mrmarc's Avatar
I imagine just as poorly as expected. After several different experiments, I've made it a point to just use 3M's 4010 for all my gyro installations, of course, after dialing out as much vibration as possible. It's such a wonderful feeling when everything runs silky smooth.
Nov 27, 2012, 05:42 AM
as much as I can
beenflying's Avatar
Finally got my TGY-211DMH servos. The first one I plugged in just rotated 360 degrees non stop. Turned out to be a bad solder joint on the pots solid wire leads on the PCB. It looks like the pots wire leads were not long enough and they have had to join/soldier them to a set of solid pins fitted to the PCB. The bare pot wires are also precariously close to the metal heat sink, so they put a small bit of masking tape on the metal case, which has virtually no sticking ability.

The servo lead is very short. I may even have to use a couple of extensions for the installation I'm doing. From the edge of the case to the tip of the plug is only 165mm. The plug is white.

Other than this, the rest of the servo looks well made and with quality components. Obviously the servo has no stop and can rotate 360 degrees.

There is a very small amount of slop in the gears and the output arm is the same splines as the Align/Futaba mini servos. So you can't use the Align DS4 arms, designed for the DS410, Henge 922/933 etc..

Five minutes on the CX-3X1000 servo tester, at 100%, left the servo just warm. Servo speed at 5.5 volts was between 0.10 and 0.11. Torque seems good, by just stalling the arm.

Now at least I can get on with the build, so I can test this gyro...
Last edited by beenflying; Nov 27, 2012 at 05:52 AM.
Nov 27, 2012, 06:10 AM
Registered User
BF...I'm kinda disappointed that one of them came with such poor soldering. Did you find the speed and travel to be consistent with all of them?
Nov 27, 2012, 08:28 PM
as much as I can
beenflying's Avatar
Yes, the soldering issue has left me a little nervous. The canopy/boom for this FAST heli is USD$59, so I would hate to crash due to a servo failing.

I ran up all 3 servos on the bench on the VCTRC, set to 200Hz, and they appeared to work fine. The limits on the gyro were still set to factory, so I couldn't see a lot of travel. I've only had the one that had the bad solder joint on the tester, so far.

FYI, the Align DS5 servo arm fits this servo, but they are too long for the elevator servo, and need to be cut down.
Nov 28, 2012, 09:39 AM
Registered User
So when is the video coming?
Dec 01, 2012, 06:16 AM
as much as I can
beenflying's Avatar
It's been a lot of work, but it getting close to flying now...
Dec 01, 2012, 06:37 AM
as much as I can
beenflying's Avatar
A few more with the flash on:
Dec 01, 2012, 07:02 AM
Not da momma!
mrmarc's Avatar
Looking sweet!
Dec 01, 2012, 08:30 AM
Registered User
Looking good BF... what are we missing to get it in the air?
Dec 01, 2012, 11:17 AM
Zippy Puffer
2Doggs's Avatar
Looks great! You can really get an idea of how low the head sits by seeing how close the blades are to the anti-rotation guide!

I guess the VCTRC is too bulky to go aft, requiring the side mount, where it's nicely accessible. Pity there can't be two aft body panels to complete the faired-in enclosed look.

As a matter of interest, what camera do you use? You seem to get great macro shots on a lot of stuff.
Dec 01, 2012, 10:28 PM
as much as I can
beenflying's Avatar

Maiden flight

And it flies well also , albeit a little tail heavy. I really can't understand why ALZRC would make a 450 more tail heavy and then restrict the battery from going any further forward than before.

But now back to the gyro. I can't fault it, so far. Setup was easy. The red light on J (6 degrees) told me I had the arms too long, so in one hole and all was good.

Everything worked as per the supplied electronic manual and the MB v1 manual. The defaults had all my servos working in the correct direction, and all I had to do was to reverse the Aileron in the Tx. Gyro direction was correct for the cyclic and reversed for the tail. Piro optimization also needed to be reversed.

I set the parameter B to blue (radio), as I like to use the same expo for all of my helis. All the other settings were default.

I set +/-12 degree for collective pitch, and max travel for the tail.

I'd forgotten to set the ESC throttle range, so the lift off RPM was quite high. The heli lifted into a smooth hover. All seemed good so I went to idle up 1 and the heli started to shake.

Back to normal and on the ground I set pot 1 to ~11 o'clock. This time idle up 1 was smooth, so I did a piro, which resulted in the wag of death. I quickly switched out of idle up 1, knowing I had a lower gain on normal, and the wag stopped.

Back on the ground I found I had the tail gain set to 44. I'd copied my 450 Pro G31 model for this model and the G31 needs a gain of 44, compared to most of my other gyro that like 28 to 32.

I set it to 32 and the tail was excellent. Better than the G31 on a 450, and I'm using the exact same DS520 I was using on the G31, before I changed it to get rid of the stop bounce.

Unfortunately at that point I had to go out and when I got back it was blowing pretty bad. Even still I balanced the blades, filed the burrs off the blade grips (Tarot DFC head) and up I went again. It handled the wind really well and I didn't fell like I was having to put in much collective to catch the heli, when the wind suddenly stopped. I finished the pack but decided not to risk flying again.

This gyro is a keeper on this heli, but I'm not a big fan of the ALZRC 450 FAST. It's just too restrictive as to where you can put things and the canopy is a PITA to take on and off. The tail boom holes were out of position and needed to be filed after being drilled (where they showed) and the tail boom cracked when I tightened up the front end at the boom mount.

I like the TGY-211DMH servos. I'm still using them at 5 volts and they still look fast. I need to figure out how to change the Align BL35X's BEC to output 6 volts. I expected, because it was one from a kit, that it would already be set to 6 volts, like my Align 450 Sport's one was, but when I checked it was only 5 volts.

The Tarot DFC head flies well and my only gripe is the burrs in the blade holders. I like my blades to move smoothly and the Tarot blade arms just bit into the blades and locked them at the one spot. Tarot needs to look at this issue. I've now had this with the tail blade holders and the main blade holders. It spoiled what was a near perfect head.

So to sum up. I can't really fault the VCTRC FBL unit, so far. If I was going to nit pick, Piro CCW needed a bit of right aileron, but so does my 250 with the ZYX. The Tarot DFC head was only spoiled by the burrs in the blade grips and the TGY-211DMH servos were only spoiled by the one servo that had a bad solder joint. I can live with the larger output arm splines, as there is a large selection of Align and Futaba arms available for this size. The ALZRC Devil 450 FAST looks good in the air, but this does not overcome the numerous other issues it creates. It's made me kinda glad I bought the Align 700 now, as opposed to the Goblin 700 (plus parts availability and price, was a major reason as well).

Hopefully a video when I fix my hat cam, and the weather improves.

BTW, the camera I use for all of the macro shoots, is the Sony DSC-T10 compact camera.
Last edited by beenflying; Dec 02, 2012 at 05:48 AM.
Dec 01, 2012, 10:47 PM
Zippy Puffer
2Doggs's Avatar
I think it's probably a lot easier to place components in a larger faired-in heli than a 450. Hope ALZRC address the fit issues you mentioned. Good to know the VCTRC unit is a contender, and look forward to your 700 build!
Dec 01, 2012, 11:27 PM
as much as I can
beenflying's Avatar
It wasn't just the component placement, but the fitting of the canopy, as well. I watched a video of someone fitting the X5 formula canopy and that was a bit of an act, as well.

Yes, I'd like to see ALZRC bring out a Mk II 450 canopy, that allowed more room for things. Even the 480 looks a lot better than the 450. I see they even brought back the gyro tray behind the AR bracket, in the 480.
Dec 02, 2012, 12:59 AM
Registered User
Excellent review BF. So in a nutshell a carbon copy of the HB800..?

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