Mark Jardini wrote:

The belt can be seen and inspected through it s length. The center
portion of the mast is enclosed trapping the belt within by some mid
shaft cross sectional enclosings. I can only assume this is one of
those fiberglass impregnated toothed belts they use in cars that last
60k miles.

My guess would be you send the mast back to be opened and reclosed or
you buy a new one.....

My Nimbus 4DM syndicate has had two engine drive belt failures over
the last 8 years, one at the launch point just before the after-C of A
test flight six weeks ago. The belt was changed within a week, but
could have been quicker had we stocked a spare.

In the case of any belt-driven MG engine, there really should be a
relatively straightforward way of replacing the belt if it fails,
without rendering the engine unit unserviceable for a considerable
time. After all, preventing lands-out is the whole reason for having,
and paying for, an engine installation.

Ian Strachan
Lasham Gliding Centre, UK