On Sat, 15 Jan 2005 09:18:38 -0600, AINut wrote:

I know it's back to basics, but I still don't quite have this one down.
A Mustang II is rated at 1600 lbs in the utility category, but no spec
is given for the normal category. Normal cat will allow a higher weight
capability, AIUI. Is the difference between the two based solely on how
hard you G-load the plane during flight? What about landing weights or
if you prang it pretty hard? (Of course, none of US ever do that!) 8-).

Mustang IIs are not in the utility category. They are in the Experimental
category, where there are no requirements for structural integrity.

With that said, homebuilt designers often claim their designs meet normal,
utility, or acrobatic category load limits. What that really *means* is solely
up to them. The general assumption is that the aircraft meets the required
limit loads... +3.8 for normal category, 4.4 for utility, or 6.0 for acrobatic.

So an airplane that is designed for a utility class rating at 1600 pounds should
be able to withstand about 1850 pounds if the G is limited to the normal
category limits (4.4/3.8 x 1600)

Whether a designer's claim that the aircraft meets normal, utility, or aerobatic
limits also include the 1.5x safety factor, the requirements whose levels are
also based on load factors, or the landing gear requirements (of which some
allow weights less than gross weight) is solely up to them.

Finnish regulations require ALL aircraft comply with FAR 23 requirements. Back
in the '70s, a Fly Baby underwent a full Part 23 structural testing regimen:

http://www.bowersflybaby.com/safety/...oad_Report.pdf

Ron Wanttaja