depressurising the rest of the aircraft. The
World War Two Paci c bombing runs from
the US island base of Tinian to Japan
involved a 13-hour round-trip, and crew
members would often sleep in the tunnel on
their way back to base.
According to Don, the B-29 was an
extremely advanced aircraft for its time.
“This was the rst pressurised bomber. This
aircraft had on-board radar and the Norden
bombsight, which was connected to the
autopilot so that the bombardier could y in
the airplane in the last ve minutes of her
bombing run.”COMPUTER-CONTROLLED
FIRING SYSTEM
Most astoundingly, the B-29’s ve pairs
of Browning M2 0.50 machine guns were
remotely controlled using an on board
computer. Known as the General Electric
Central Fire Control system, it used
analogue computers made of vacuum tubes
that enabled a gunner to spot attacking
aircraft in a separate dome ‘sighting station’,
and to re the Brownings that were mounted
in their own turret. Having the two separate
allowed the gunner to stay inside the B-29’spressurised cabin; keeping him warm and
unencumbered by thick ight clothing.
Better yet, any of the gunners could
‘slave’ two or more of the machine gun
turrets to their speci c aiming computer, for
massed ring on attacking aircraft. The B-29
had ve pressurised sighting stations (tail,
nose and three Perspex domes on the sides
and top of the fuselage); giving complete
visual coverage of the aircraft duringbombing missions. The guns were aimed
using optical tracking terminals; one at each
gunner observation/ ring station. These
could be adjusted to match the wingspan of
the attacking aircraft, ensuring that its course
was accurately projected during combat.
“To establish proper calculations,
a gunner would focus a series of dots
from his gunsight onto an enemy target
and follow it brie y,” said a 2015 Popular
Mechanics article entitled, The Cannonson the B-29 Bomber were a Mid-Century
Engineering Masterpiece. “This would allow
the computer to calculate range and speed
of the enemy aircraft. Altitude, outside air
temperature and speed were all available to
the computer to determine the lead required.
A bomber ying at 250mph at 30,000ft
will curve a bullet approximately 36ft. The
computer would also compensate for gravity.
A 0.50-calibre bullet will drop almost 14ft at
a range of 800 yards. Add in the variable of
a ghter plane closing at 400mph – which
the system would also consider – allowed
gunners to simply drop their sights directly
on the target and re away.” (The entire
article by Chris Clarke with video is available
online at http://www.popularmechanics.com)
Boccaccio added: “The B-29’s computers
were capable of calculating where the
[Japanese Mitsubishi A6M] Zeros were
going, and converging two or more guns
to re at that point. As long as you kept the
attacker’s wings within the aiming circle, the
computer would calculate the distance and
airspeed. The gunner didn’t have to guess
anymore.” Such was the prowess of the
B-29’s remotely-controlled gunnery system,
that these bombers did not need ghter
protection during forays into enemy territory.
All told, the B-29 was truly a
technological marvel. This is why the total
cost for designing and manufacturing the
B-29 exceeded $3bn; $1- $1.7bn more than
the Manhattan Project that built the atomic
bomb. Not all of the Superfortress was
high-tech though: “Over water, the B-29’s
navigator had to use the stars and a sextant
to calculate their position,” Boccaccio said.WORTH THE VISIT
As big as it is, this airframe is packed to
the gills with equipment. For instance, the
corner of the navigator’s table had to be
hinged, to allow a top-protruding gunnery
turret to be lowered and raised. The cockpit
contains elevated pilot and co-pilot chairs
above the bombardier in the nose, and the
other positions (radio and engine control)
are packed into this space. For aircraft
enthusiasts, the B-29 is a wonder to behold.
So if you can manage it, make the time to
catch either FIFI or Doc as they tour North
America. You will be more than glad that you
did. http://www.airpowersquadron.org34 Aviation News incorporating Jets November 2018
‘All told, the
B-29 was truly a
technological marvel’
Above: Rear lower turret of FIFI. James Careless
Below: A ne sideview of the B-29 with bomb bay doors open. AirTeamImages.com/Steven Marquez