KC-135 From Eisenhower Era Flies On For PA ANG
by Aero-News Senior Correspondent Kevin R.C. "Hognose"
In 1959, cars had tailfins, which
peaked that year with the Cadillac Eldorado and various Chrysler
products. Kids learned to "Duck and Cover." The New York Times
admired Fidel Castro. And the US Air Force ordered a block of
KC-135A-BN Stratotankers, Boeing C/Ns 17931 to 18011, USAF serials
59-1443 To 59-1523.
One of the surviving KC-135s, 17948 to its Seattle factory and
59-1460 to the Air Force, was brought to Embry-Riddle's Florida
Skyfest by its current proprietors, the 171st Air Refueling Wing of
the Pennsylvania Air National Guard. The plane was decorated with
attractive nose art displaying an eagle and the legend "Classic
Iron," which basically sums up the Pittsburgh-based crewmembers'
pride in their old, but clean-enough-to-eat-off-of, jet.
The 171st is based at Pittsburgh International Airport and has
400 full-time and 1000 part-time Guardsmen. They operate 16 KC-135T
jet tankers, which once fueled the high-flying SR-71 reconnaissance
fleet, and now support Air Force and allied missions worldwide.
The KC-135 can transport cargo or personnel, or carry fuel for
inflight refueling. It doesn't have the nose or tail doors that
usually define military cargo planes, but it has a side cargo door
like those on cargo conversions of airliners. It can be fitted with
airline-type seat units -- with the seats facing to the rear -- or
paratroop-type seats along the side of the plane. (They're only
paratroop-"type" seats. The airplane is not designed for
intentional parachute jumps).
In tanker mode, the plane can deliver fuel to US Air Force
aircraft through a high-volume fueling boom that is "flown" into
position on the receiving aircraft by a highly trained enlisted
aircrew member, the boom operator, as the receiving aircraft's
pilot maintains a close formation. The boom operator lies in a
ventral position in the aircraft, looking through a window and
flying the boom with a control stick. Naval and foreign aircraft
can refuel with a probe-and-drogue system as well.
This specific plane has an interesting history. It was the 363rd
KC-135 built of 820, and made its first flight on February 16th,
1960 -- the Air Force accepted it within ten days. Tankers were
then, as now, vital to national security. Ike was still President,
and no one serious was talking about sending men to the moon, and
the Strategic Air Command maintained a standing patrol in the sky,
ready to rain nuclear death on the air bases and cities of Russia,
should they do the same to us.
Old 1460 spent some time as a as a KC-135A before being modified
to carry special JP-7 fuel for the SR-71A reconnaissance aircraft.
Normal JP-4 (which used in those days), freezes at the high
stratospheric altitudes where the SR-71A operated, and so, special
fuel with a much lower freezing point -- JP-7 -- was compounded.
The SR-71A fuelers, including 1460, were dedicated to that mission
and were designated KC-135Q. Fifty-six of them were converted in
Most of the changes were in navigation and communications
equipment, but the KC-135Q also needed to keep its own fuel
separate from fuel it planned to offload (regular planes could use
JP-7, but the SR-71 couldn't use JP-4 or its replacement, JP-8,
which is basically Jet A with a military additive package).
After the SR-71A was retired in the 1990s, the KC-135Q fleet --
including 1460 -- was reconverted to service conventional
At ERAU's Florida Skyfest last weekend, on Saturday, 1460 was
open to the public for tours. Many members of the public express
surprise about how open the plane is. They expect it to be full of
fuel tanks, but the KC-135s entire fuel load -- for itself and that
it can offload to other aircraft -- is borne in the wings and under
the reinforced cargo floor. Even when fully laden with fuel, the
cargo bay is wide open. Weight considerations prevent fuel and
cargo from being carried at once.
The original KC-135A was closely based on the original Boeing
"Dash-80" demonstrator (which actually tested the prototype
refueling boom), and was a forerunner of the legendary 707
Over the years, the KC-135 fleet has seen many changes and
upgrades. There have been two complete powerplant replacements,
numerous cockpit overhauls, and aerodynamic fixes (the whole fleet
was retrofitted with a taller fin to increase yaw stability).
For many 135s, the original J57-P-59W turbojet engines were
replaced by refurbished low-bypass turbofans removed from
decommissioned commercial 707s, called the Pratt & Whitney
TF33-PW-102. This gave the tankers better fuel efficiency, less
visual signature (smoke), and something they hadn't had before --
thrust reversers for increased safety.
A much more comprehensive program to re-engine KC-135s was
undertaken in the 1990s. The TF33s or J57s were replaced with CFM56
high-bypass turbofans which yielded even larger efficiency,
noise-reduction, and maintenance gains. Of course, the additional
thrust provided by the successive generations of engine is a big
improvement, too. This upgrade replaced the entire engine pylons
and nacelles on the affected KC-135s -- and involved over twelve
linear miles of new wiring per plane.
Increased fuel efficiency from the turbofan upgrades - 25% in
the case of the CFM-56 swap -- has tactical, not just economical,
significance. With less fuel needed to haul the tanker itself, more
is available to offload to tactical aircraft, mission profile
Fatigue and corrosion are bitter enemies of older airplanes, and
all KC-135s have had major wing work to combat fatigue. The lower
wing skins, which bear much of the air loads, were replaced by
parts not only of new design but of an improved alloy that was not
available when the original plane was made. Each rebuild required
564 parts, 1,500 square feet of aluminum, 32,200 steel fasteners
and 19,500 aluminum rivets.
1460 has seen its share of changes, receiving its new wing skins
in December, 1981, and the CFM-56 powerplant upgrade on December
20th, 1994 which made the plane a KC-135T.
She also displays war honors, proudly bearing the ribbons of the
Air Force Distinguished Unit Award with Oak Leaf Cluster, and
Southwest Asia Service Medal with two battle stars.
Like any old lady who's aging gracefully, the KC-135 spends more
time primping than her youthful equivalents; Air Force figures
suggest that it takes 16 maintenance hours per flight hour. That
keeps a lot of the 1400 men and women of the 171st Air Refueling
Wing busy, because tankers are always in demand.
Several attempts to replace the KC-135 flight have come to
naught. A new attempt even now is underway. But for the time being
the 171st will be flying what they like to call Classic Iron.
Boeing engineers are cautiously optimistic that the KC-135 fleet
could fly on into the 2020s and beyond. Not bad, for a plane that
might have been designed by their grandfathers.
Not many things survive from the 1950s, but the surviving
tailfin Cadillacs are now classics. And people still want to
blow our kids up. The New York Times still admires Fidel Castro.
And KC-135T 59-1460 is still going strong.