Friday, October 20, 2017
Home » Product Reviews » Gaui Flybarless E-Stabilizer GU-365

Gaui Flybarless E-Stabilizer GU-365

One of the coolest heli developments I have seen over the last couple of years is the advent of flybarless technology. Getting rid of the flybar and its paddles has long been a desire for the scale helicopter crowd for a more realistic appearance. On the other side of the flight line, flybarless rotor systems promise increased efficiency for the ever power-hungry 3D guys, along with the unique visual appeal. Until recently the big stumbling block for many has been the cost. The most sophisticated systems easily run to several hundred dollars. Fortunately Gaui has changed that landscape with the recent introduction of their GU-365 Flybarless E-Stabilizer System. The GU-365 kit is adaptable to many 450 size helicopters, and I installed it on a T-Rex 450SA that I had landed inverted, taking out most of the original rotor head in the process. The 365 includes a rotor head with everything you will need from the swashplate up, as well as the magic black box that controls it all. My disassembly technique made it impossible compare weights with the original setup. With significantly less parts though, the flybarless option has to be lighter, especially since the 365 also replaces the traditional tail gyro.
The mechanical components are nicely machined aluminum with an attractive neutral gray anodized finish. The physical installation only takes a few minutes. Strip off the old head down to the swashplate and set it aside. Slide the Gaui follower down over the main shaft and connect it to the swashplate. The rotor block goes on next and mounts as expected with the traditional Jesus bolt through the top of the shaft. The kit includes extended length upper control rods, so you just need to install a couple of ball link rod ends, ensure they are the same length, and connect the blade grips to the swash plate. The last step is to zero the blade pitch and clamp the swash follower to the main shaft with its arm level.
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Save couple of extended pushrods, this is the extent of the mechanical components for the Gaui flybarless system.  No, the Thunderpower blades are not included in the kit.  The view above shows just how clean the installation really is.  The asymmetric swash follower doesn’t seem to significantly increase vibration.
The GU-365 is the heart of the system, incorporating three-axis gyro stabilization and the smarts to make everything work seamlessly.  Setup and programming is straight forward, and is a combination of setting the dip switches, trim pots, and electronic inputs from the reciever. TIPS FOR SUCCESS
There were a couple of minor hitches on the mechanical install, but nothing that wasn’t easily overcome. The head block was slightly loose on the main shaft but I was able to snug it down with a little care when tightening the Jesus bolt. The swash follower was also loose on the shaft, and I slipped up here. I tried to secure it simply by tightening its clamping screw, and stripped the threads in the follower. The real kick in the pants came when I removed the follower and gave it a light squeeze with a pair of smooth-jaw pliers. The aluminum yielded readily, allowing me to easily tighten it to the shaft once I replaced the bolt with a longer version and a nylon locking nut. Live and learn, then pass it along so someone else
FLIGHT COMMENTS
Local heli guru Tony Yap got the nod for the initial test flights. He found the T-Rex bouncing a bit in pitch and roll. Like a wagging tail rotor, this was a function of too much gyro gain, and was easy to dial out. The GU-365 is extremely sensitive to vibration, and during these first few flights the T-Rex would periodically give an uncommanded slow right roll. It wasn’t that big a deal at altitude, but it sure was unnerving down low. Tony attached a washer on the case to change the resonant frequency enough to eliminate the issue. After a few more flights including some low inverted work and a few basic 3D maneuvers, Tony gave it his blessing, confident that I could handle it from there. I have found that this system works very smoothly, and with the flybar now gone it gives the heli a clean sleek appearance and different sound. I consider myself an intermediate heli pilot, and have really enjoyed setting up my T-Rex with this system. There is definitely a faster handling response with the flybarless setup since the main rotor does not have to fight the mechanical feedback of a traditional flybar during aggressive cyclic inputs. For example, flipping and tumbling maneuvers can be much tighter with this system. The manual instructs you to decrease the aileron and elevator throw, and add expo specifically to counter this until you get used to the new handling feel. Another unique feature is that the gyros are trying to fly the helicopter all the time, instead of the purely mechanical feedback system of a traditional setup. Because of this, you will want to be aware that ground resonance can cause some unwanted inputs while you are spooling up. As long as you watch for and correct these inputs before lifting off you will be fine. You don’t want to throttle up and passively wait for the rotor to come up to speed.
can avoid the same mistake. The manual directs you to initially connect the servos directly to your receiver. I did so, and confirmed that the servos and linkages were all properly centered and set. The GU-365 gyro box contains multiple gyros to control motion in all axes. Install the box between your servos and your receiver. This is the same as plugging the rudder servo into a gyro, and the gyro into your receiver, there are just more connections. The manual detailswhich plugs go where, and also recommend that you leave a good loop to avoid transmitting any airframe motion to the Gaui controller. I installed the controller under the fuselage frame, set the dip switches as instructed, and then turned to my transmitter. The manual gives precise instructions to reduce the CCPM mixing percentages and to add expo. I followed the recommendations to the letter and all has worked out very well. The one step in the programming process that seems a little unusual is that you need to program the Gaui gyro unit after setting up your transmitter. This feels very similar to the process of binding receivers to the DX7. The process is detailed in the manual and I had no troubles. The last step before flying is to confirm that the gyros are working properly. Temporarily setting the gains to 100 percent will help you confirm that as you tip the helicopter forward in pitch that the swash tilts aft. Similarly, you want the swashplate to tilt left as you lean the helicopter to the right. Set the rudder limit pot to give full motion of the tail rotor pitch slider without it jamming the mechanism at the extremes. I am using a set of Thunder Power’s 325mm carbon fiber blades, and the gap in the Gaui grips gave just a little more slop than I was happy with. I made a couple of .010 nylon shims with my sherline lathe, but metal washers would work as well if needed available.
  CONCLUSION
Gaui’s GU-365 offers the cool factor and advantages of a flybarless setup for a fraction of the traditional cost. The setup and programming only took an evening before my T-Rex was ready to fly. It has performed to spec without a hitch since the initial tuning and been a lot of fun. If you want to clean up the look of your machine and reap the benefits of some of today’s latest tech, this is a very compelling option.
Links
Gaui, distributed by Empire Hobby
www.empirerc.com,
(480) 982-0909
Thunder Power www.thunderpowerrc.com,
(702) 228-8883