ORIGINAL: Jim Cattanach
I was flying my MB339 the other day & had four great flights. A couple of minutes into the next flight, there was a loud bang & the turbine stopped. I managed to land ok. The force of the incident had broken one of the wooden turbine mounts & the turbine had turned in its own mounts, causing them to twist. I removed the turbine & saw that two blades were missing from the turbine wheel & the tailcone was bent & twisted. There was rattling from under the FOD cover. When it was removed, a number of screws fell out. The festos had all been destroyed.
I bought this turbine new just over a year ago & it has not had much running. As Wren only guarantee their turbines for a year, it will be out of warranty. I have shipped it back to them for examination & can only hope they agree that this type of incident is not what would be expected & repair it at a reasonable cost. It looks an expensive repair.
Has anyone else had a similar incidentwith a Wren 160?
If it looks anything like these pictures, then it is simply a bearing failure. To say it "explodes" is a little overkill. When a bearing fails, the turbine stops spinning abruptly and can shear bolts and spin in the mount.