2-56------------------NEVER had a failure up through---yes THROUGH --- 5.1cu.in.and 100" span on a scratch 260.

For some (not all) fly ins 4-40 is specified-------never had a failure there either. Competitions?? well adhere to the rules or don't fly----it's that simple.

2-56 is simply vastly under rated-----BUT that's what the rules say sooo-------OK.
As far as air-load/vibration failure my rather extended experience indicates zip, nada,nyet etc.

My flying group has never had one either and most of us have been at it for more than a short time----I believe the least experienced flier we have in the group has been flying for 25 years.

I expect a lot of nay-sayers and flames---------won't do any good because those are the facts!

Edit-------then again, we've got that ever present group who break anvils with a rubber hammer---let's face it, nothing is fool proof! ---------perhaps knitting; crocheting????