Re: OT F-117 retired

David Lesher wrote:

Pat Flannery <flanner@xxxxxxxxxx> writes:


I'd read up on this fault in the design, and I think what happened was
that Boeing was quite conservative when designing the B-17, and built it
a lot stronger than it needed to be to be on the safe side- which paid
off when it came to absorbing battle damage.

It's not a question of raw strength - Both the B-17 and B-24 were pretty
much even in that regard when undamaged. But - the B-17 used a multi-spare
wing with Warren Truss type spars. The B-24 used a single-spar (I-beam,
more or less) wing. It's harder to damage a B-18 structure enough to
compromise it.

In the case of the B-24, the performance of the aircraft regarding range
and bomb capacity took the lead, and the result was that the structure
was built fairly light, and couldn't tolerate the degree of damage a
B-17 could.

It also used an airfoil more highly optimized for low drag at the cruise
point, which gave better performance at that point, but was less well
behaved when "off-design". That may not sound like much, but a B-24
formation is 15-18 airplanes wallowing around "off-design".


But that did mean you needed fewer aircraft to accomplish the same
mission.

Only if the loss and abort rates are comparable. The B-24's less, shall we
say, airplane friendly fuel, electrical, and hydraulic systems meant, on
the whole, more aborts.

That means you need to look at not just % of flying a/c on 12 May
who were destroyed, but also the "more B-17's needed vs -24" factor
meaning that there were more 17's up there....

There's something that's being passed over. here, as well. Flying
Qualities. A B-17 was a delight to fly, with very little in the way of bad
behavior. The airplane was as honest as the day is long. Yes, it takes
some muscle to shove it around, but it responds. The bloody thing is so
well-balanced that you can trim out _all_ the foot loads from asymmetric
flight - (As in no rudder force to keep the pointy part forward with 2
engines out on one side. The systems were so well thought out and mature
that system management was as intuitive as it would get.

The B-24 was, by comparison, damned uncomfortable to fly, especially in
formation. Consolidated and Sperry ended up having to develop the
"Formation Stick" - a stick-steering autopilot to ease Pilot Fatigue on
formation flights. The you add in the B-24's dodgy ditching
characteristics, its weakness during rough landings (When the top turret
would collapse into the cockpit) and general tendency to try an blow itself
up whenever possible, and it all comes out as a wash.

It's worth noting that the B-17 wasn't retired from the USAF until the late
1950s. (It served in Rescue, Photo-Mapping, and Weather Recon roles, as
well as as a Utility Transport and Pilotless Aircraft. (AS in both a target
and as an air-sampler for A-and H-Bomb tests. The B-24 was dropped like a
hot potato, and was pretty much gone by 1948.

--
Pete Stickney
Without data, all you have is an opinion
.

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