On Sep 22, 4:06*pm, Don Johnstone wrote:

...The RAF bought 100 Grob Acros, 99 went into service and 1 went to
Slingsby for testing on a rig...

We should be cautious about confusing anecdote with data. The testing
of one relatively conservatively-designed trainer doesn't tell us much
about the strength of the average sport or racing sailplane.

It may be that this one example tells us more about Slingsby's welding
than about Grob's composites.

Thanks, Bob K.