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.