Boeing to request an airliner that could operate on ‘long and
thin’ routes. These were to destinations beyond the range of
the L-1011 and DC-10, with passenger numbers too low to
justify the use of a standard 747.
It was at this point that Sutter’s decision to retain the four-
engined configuration paid dividends and the projected long-
range performance of the 747SB made it ideal for both Pan
Am and the Iranians. Within weeks Pan Am had ordered ten
aircraft and Iran Air soon followed suit.
Green Light
The Pan Am order alone was valued at $280 million and gave
the project sufficient impetus to progress beyond the drawing
board. By mid 1973 the aircraft had been re-designated as the
747SP (Special Performance) and Boeing projected a market
for 214 airframes, with a break-even point of 45 sales.
Sutter and his team finalised the design with a length of
184ft 9in (56.31m) – some 48ft 4in (14.73m) shorter than
the standard 747-100. They surmised that this, combined with
other weight saving modifications, would result in a weight
reduction of 45,000lbs (20,412kg ) but the jet would still be
able to accommodate around 280 passengers.
The wing was essentially unchanged but used lighter
materials throughout and the complicated triple-slotted flaps
were replaced by simple single-slotted units. The wing also lost
the under-wing ‘canoes’ that housed the flap mechanisms on
larger 747s. The tailplane was 10ft (3.05m) greater in span and
the vertical fin was also extended slightly.
With development progressing on schedule, the first 747SP
(the appropriately registered N747SP) was rolled out of the
factory on May 19, 1975 and performed its maiden flight
on July 4 – ten days ahead of schedule. The honour of making
the debut outing fell to Jack Waddell, who had also flown the
prototype 747 on its first sortie.
N747SP was aloft for three hours that day and explored the
entire flight envelope from stall speed to a VNe (never exceed
speed) run of Mach 0.92.
Flight testing proceeded without incident and the
lightweight 747 soon revealed itself to be a spectacular
performer. With a reduced all-up weight but retaining the
same thrust as a ‘full-sized’ 747 the ’SP was impressively quick.
Record breaker
Keen to promote the new aircraft’s capabilities, Boeing seized
on this newfound speed and on November 12, 1975, the
fourth prototype flew non-stop from New York to Tokyo in 13
hours and 33 minutes – with 200 passengers on board! When
the aircraft had completed the 6,927 miles (11,148km), it even
had over 30,000lbs (13,608kg ) of fuel remaining.
Needless to say, the aircraft sailed through its type certificate
programme and the FAA certified the 747SP for passenger
flying on February 4, 1976.
Into service
The first example was delivered to launch customer Pan Am
on March 5 and the type carried its first fare paying passengers
the following month. ‘Clipper Freedom’ (the record-breaking
Air Namibia 747SP
V5-SPF began life
with South African
Airlines in 1977 as
ZS-SPF. It joined
Air Namibia on
lease in 1990 and
was operated until
1998 when it joined
Linhas Aeras de
Mocambique.Air China’s B-2454
was originally built
for Braniff in 1981 as
N1608B but was never
delivered. It joined
CAAC in 1982 as
N1301E and became
B-2454 when the
airline was rebranded
as Air China in 1989.Two TWA aeroplanes
were later sold to
American Airlines,
which used them on its
Dallas-Fort Worth to
Tokyo service as well
as operating routes
between New York
and London and
Brussels. N601AA
served TWA as
N57202 and joined
American in 1986.Iran Air f lew just four
’SPs. These included
EP-IAA, which was
eventually retired in
2014 and is currently
stored in TehranPan Am 747SP
N539PA ‘Clipper
Black Hawk’
approaches Hong
Kong’s Kai Tak
Airport in January- It later joined
United Airlines as
N148UA and was
then sold to the
Go ernment of Qatar
a s V P-B AT.
A M B
http://www.airlinerworld.com 33SUTTER came up with the
decision to ‘chop’ his beloved
747