"Veeduber" wrote ...
A couple of days ago I was digging through a file looking for... I can't
remember what... when I came across a blurry copy of a 1930's article by
Raoul
J. Hoffmann, the aeronautical engineer who crunched the numbers for Matty
Laird. Hoffman was one of my dad's heros and it was a good choice. The
article was titled 'Landing Gear Shock Stresses' and included the usual
boilerplate formulae, a couple of graphs and a few column-inches of text.
I'd
seen it before, hadn't looked at it too closely since I'd already decided
to
emulate Vernon Payne's method of using the worse-case drop height. But as
I
scanned the article something jumped out at me.

"...drop from a height in inches equal to .38 times the calculated
stalling
speed in miles per hour... (but) ...not over 15 INCHES for conventional
airplanes."

FIFTEEN inches. Not fifty.

You could have backed out the number from FAR23.473(d) but who reads the
regs.

(d) The selected limit vertical inertia load factor at the center of
gravity of the airplane for the ground load conditions prescribed in
this subpart may not be less than that which would be obtained when
landing with a descent velocity (V), in feet per second, equal to 4.4
(W/S)\1/4\, except that this velocity need not be more than 10 feet per
second and may not be less than seven feet per second.

Rich