clareprop (#8),
Bit far back, but have just had a look at this Thread. Your:
..."there must be a risk of a 'wing-tap' from time-to-time?"...
In 1942, in ole Alabam', our USAAAC instructors used to playfully tap our AT-6 wingtips together for fun, no harm resulted
AFAIK.
We thought it was great, but "don't try this at home !
Danny42C.