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Trex 500 Canopy Mount Modification

November 6th, 2009 No comments

Trex500 – Standoff Mod – Side2During the recent build of my newly acquired Trex 500, there was one small concern that jump out at me and that was the rear canopy standoff’s…and how shit they are (that aside the Trex 500 is great quality and value). And it’s not just because the canopy mounts are plastic, as plastic mounts will often save your frame in a crash. The issue is the canopy mounts don’t seem to sit far enough in the canopy lug holes and/or with enough tension for my liking (I normally upgrade the canopy mounts to “thumb-screw mounts”). Also there have been a few reports of Trex 500’s loosing canopies in-flight, either way something needed to be done and there are no thumb-screw upgrades currently available.

It turns out you can fit a pair of Trex 700 canopy mounts with a small amount of modification and as luck would have it, I had some lying around as I upgraded my 700 mounts to QuickUK thumb-screw mounts.

The main modification is to the plastic swash guide, the main frame is essentially untouched. One concern with the modification is in a crash the metal mounts will transfer more energy to the frame (rather than bending/snapping like the plastic counterpart), my solution to this was to cut 2 small sections of carbon fiber and bolt them to the frame using existing frame holes. This effectively doubles the frame width around the canopy mount point and hence reinforces the frame.

The Modification

The Trex 700 standoffs uses M3 bolts (into steel) and the Trex 500 uses M2.5 bolts (self tapping into plastic). So you will need to enlarge the canopy standoff holes in the frame just enough to accommodate an M3 bolt, which should easily be done in a few seconds by rubbing a small drill bit inside the canopy standoff holes.

The swash-guide also needs its bolt holes enlarged enough to accommodate a M3 bolt (you need to source 2x M3 bolts), note that the M3 bolt will not be tapping and held by the plastic (although it will be a tight fit). The trick with this is there is not a huge amount of meat on the plastic so you need to drill very straight and not make the hole to large. That said, if you make the holes too small the plastic will crack when you push/screw the M3 bolt through. When you have drilled through to the end you will notice the center support pin start to fall away…which is fine cause we don’t want it any way :) Finally cut away any protruding plastic in order to allow the M3 bolt head to sit snug against the inside of the plastic bolt hole. Bottom line is if you stuff up the plastic swash-guide modification it’s only a couple of £ to replace. I brought a spare, however I manage to get the modification right the first time. Installing the swash-guide and bolts back into the frame is simple, a ball-end hex driver is a requirement though.

Frame bracing around the bolt hole is optional but recommended and if you’re like me you probably have an old broken frame you can use for carbon. I wont go into detail you just need to cut some carbon to match the frame around the bolt hole (see below) and drill some holes in the brace to match the location of the rear bearing bock bolt hole and canopy mount hole. You will need to also source 2 slightly longer M3 bolts, that’s it.

Installed Trex 700 Canopy mounts on Trex 500

Trex500 - Standoff Mod - Back

M3 bolt snug against modified swash-guide (need ball-end hex to gain access)

Trex500 – Standoff Mod – Side3

Installed carbon brace for canopy mount/standoff

Trex500 – Standoff Mod – Side