Andrew Chaplin wrote:

ArtKramr wrote:

Subject: Distribution of armor on a B-52
From: Andrew Chaplin
Date: 8/7/2004 8:57 PM Pacific Standard Time
Message-id:

ArtKramr wrote:

Subject: Distribution of armor on a B-52
From: Bob
Date: 8/7/2004 8:46 PM Pacific Standard Time
Message-id:

None..


You mean it had no protective armor? None?

Yup, he means zilch, zippo, three fifths of five eighths of f*ck all.

Sheesh !

I gather the A-10, the Su-25 and a few attack helicopters are the only
a/c flying with armour these days. AC-130 may have some armour, but
I'm not sure.

Most tactical jets have some armor protecting at least the pilot, although
nothing like the titanium bathtub the A-10 pilot sits in. For the BUFF and
similar nuclear-tasked a/c of its era, armor was considered irrelevant and
counterproductive to the mission. If it's only going to be used once 'for
real', and even extremely high attrition rates still allow the mission to be
accomplished (75% losses? Moscow's still a smoking hole in the ground), then
armor just decreases the a/c's performance and takes up weight that can far
more usefully be dedicated to defensive electronics or other features that
provide greater protection.

Of course, when we found ourselves fighting a drawn-out conventional war in
Vietnam where the majority of losses were to AW, AAA and SAM warhead
fragments (as opposed to nuclear blast and radiation), where it wasn't one
strike and we hold the victory celebration (in the local deep mine where
we've ensconced ourselves to while away the years repopulating the human
race and listening to Vera Lynn, waiting for the radiation levels to die
down), the balance changed. Many of the a/c used in Vietnam were modified to
decrease their vulnerability to combat damage. Sometimes armor and
self-sealing and/or flame-retardant foam lined fuel tanks were retrofitted;
in many cases redundant, separated hydraulic systems were retrofitted to a/c
like the F-105s (designed as nuclear strike a/c) that Ed flew.

The F-105 had redundant hydraulic systems, but they weren't designed with
combat damage in mind. The two lines ran side by side inside the dorsal
fairing, so a hit that took out one usually took out the other, and once all
the fluid had run out of the system the horizpntal stabilizer went to the
max. nose up positions and it was time punch out.

Understandably, pilots took a dim view of ejecting over North Vietnam
because they had no control of their a/c, so Fairchild instituted a quick
fix which, when the hydraulic system had taken a hit, allowed the pilot to
lock the stabilizer in the position appropriate for 350KIAS (IIRR. Ed will
probably remember) before the fluid ran out. They could control their
height by increasing or decreasing the throttle. That at least gave them a
shot at getting out of North Vietnam and over the Gulf of Tonkin or Laos,
Cambodia or Thailand before ejecting, where the odds of being rescued were
far higher, but there was no way they had enough control to attempt a
landing.

The final fix involved installing a separate standpipe for emergency use.
IIRR this allowed some limited control of the ailerons/spoilers for lateral
control using the trim switch, and I forget how much if any limited control
was available for the stabilizer,also using the trim. In good conditions
this might allow the pilot to make a landing at an airfield, and certainly
gave him a lot more control of heading.

Since Vietnam, far more effort has gone in to designing survivability right
into the a/c, because for the first time someone (the USAF and USN, and
beyond them the aircraft design companies, Fairchild (F-105) and McAir (F-4
and A-4) having the most data) had bothered to gather a good-sized
statistical data base about the causes of a/c losses, and then quantified
the features which were most cost-effective for the role and threat the
particular a/c design is expected to meet. Everyone had always known that
some a/c were more survivable than others, but no one had every really done
a proper statistical analysis before of just how much certain features were
worth, and the trade-offs, although there'd been some movement in this
direction by Operational Research units of the US and British (at least) in
WW2. Survivability requirements are now part of the design spec, and all
the post-Vietnam generation of US combat a/c were designed with
survivability taken into account.

Guy