On Sun, 21 Mar 2004 10:01:17 -0000, "M. H. Greaves"
wrote:

I saw a video about the extensive testing of the early 747's (not the
400's), and the test pilots had a big wooden skid attached to the rear
underside, and were taking off at too steep an angle grinding the wood skid
along the ground; amazing!!

They put an oak skid on all airliners that they're certifying when
they get to the runway work. It's not exactly special to the 747.

Not having had anything to do with Cat I/II testing for transports or
bombers (just fighters), I don't know if the USAF does the same thing
with their transport airplanes, like the C-17 and C-130. I don't
recall ever having seen it, but that doesn't signify anything.

shows just how strong they were and how they could stand up to rough
treatment; of course the one at Aukland didnt have a wooden skid so the
effect must have been quite sparking, ('s'cuse the pun!!)

It always surprises me how long they can scrape the tail along the
runway without actually wearing through the skin.

Incidentally, ground effect is only there to about half the span above
the ground. For an interesting story about flying in ground effect,
look for the remarks by the (NASA?) pilot who flew the Canadian flying
saucer.

Mary

--
Mary Shafer Retired aerospace research engineer