An unfortunate incident caused a Rex500 to plummet to the ground form about 35 feet up, the damage was surprisingly low considering, the main frame at the front took the brunt of it, the main blades, 1 cyclic servo and the battery all coped it. whilst this list is small the cost to replace the parts is still quite high, so i decided to go down the clone route.

i went with the Chinese GTB clone, its a complete air frame including tail blades (no mains) and complete head, for less that 150 quid, one of the main reasons for this is that i firmly believe that the crash was caused by the DFC head failing, in that the connecting rods have very little thread and came apart, on inspection, the wrecked copter had both rods detached from the swash.

all things considered the GTB frame is reasonable quality, the carbon stands at 2mm thick and the hard plastic moldings are also good, its a belt drive system to the tail and all the parts go together well with good tension to the belt. i got 3 full size budget servos to replace the damaged cyclic one as this is the standard size on the GTB frame. i had to make some collars for the servos for both spacing and to clamp them in.

The head is not bad quality, its a standard FBL setup that comes with the connecting rods, 2 are the same length, but the configuration of the servos means that one needs to be shorter than the other and you cant just wind the ends in, so i had to get a shorter rod to make it work.

another issue i had was that the swash guide and canopy mounts didn’t work with the size of the servo, in the end i had to drill out the holes and use a single length of carbon rod and some silicon tube to replace the too short original ones.

The tail also had a slight issue with the amount of movement on the shaft, i had to put a piece of silicone tube at the end to stop it over extending and locking the rotor.

Although i have not yet flown this model properly, i have test hovered it and it did good, no real vibration and no worrying noises, the servos are not particular fast (again budget replacements) so no super 3D stuff will be happening, but it felt quit planted and stable.