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Re: 97 UBC

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At 11:40 AM 7/2/99 -0700, you concluded a justifiably exasperated posting on
interpreting the 97 UBC:
>If anyone has any insight on the simplified method and drift I would
>appreciate there opinion. By the way, when are the seismic design
>manuals II & III available? I'm tired of these examples that have given
>forces, displacements, etc... that all figure to a clean answer or some
>assumption that is pulled out of nowhere.
>Gerard Madden
>CRJ Associates
>Design Engineer, Structural Department

Another thread's diversion onto the B-25 airplane that hit the Empire State
Building leads to the story of a B-25 problem in early 1942 that has been
repeated in the 97 UBC like noted above, but unfortunately without the same
force of resolve to fix it. 

Col Jimmy Doolittle was preparing a batch of B-25B bombers for his now
famous carrier-launched mission to bomb Japanese cities. That early model of
B-25 had a lower gun turret that was very difficult for the aircrew to make
effective use of. Doolittle is quoted as saying, "A man could learn to play
the fiddle good enough for Carnegie Hall before he could learn to fire that

Presumably the turret satisfied its designers' interest in showing their
stuff, and met an Army Air Corps specification written at a remote high
level, same as for the 97 UBC. But it wasn't operable by its users who had
to defend the airplane they were riding in so they could accomplish their
mission and fly more missions in the future. The presence of the balky
turret was not only a technical and morale burden, it gave a false sense of
security to the crew and to the strategists alike. It was a liability. Same
as for problems endemic in the 97 UBC.

Back then, we had Jimmy Doolittle, and he had the backing of the chiefs of
staff and the President, not a bunch of see-no-evil committees and
commissions who don't know who and what counts for practical results. He
ordered the lower turret eliminated and a 50-gal fuel tank added in its
place, and flew his mission mindful of the planes' limitations. Lower
turrets on B-25's were not installed after then. 

Today, we are stuck with the 97 UBC until the much trickier 2000 IBC
replaces it, and many of us are going to be unnecessarily shot down while
"flying" our missions because of its perverse, user-sabotaging shortcomings.

Charles O. Greenlaw  SE     Sacramento CA
 [B-25 ref: Mar 1998 issue of "Aviation History"]