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BAC 1-11
Oman - Air Force
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BAC 1-11
The BAC 1-11, or One-Eleven, was a short-range, jet airliner designed by Hunting
Aircraft and produced by the British Aircraft Corporation (BAC) after Hunting was
merged with several other British aviation firms in 1960.
1-11 was designed to replace the successful Vickers Viscount on its existing
routes with British European Airways (BEA) and other operators. The 1-11 was
the second short-haul jet airliner to enter service, the first being the famous
Sud Caravelle. But due to its later entry date the 1-11 was able to take
advantage of greatly improved engine fuel economy and was less expensive to
operate. This made it moderately popular with a launch-customer list including
over half of the sales to the United States, with an eventual production run of
well over 200. The 1-11 was one of the most successful British airliner designs
and served from its introduction in the early 1960s until its widespread
retirement in the 1990s due to noise restrictions.
History
In the mid-1950s British European Airways (BEA) started looking for a jet-powered,
600mph design to replace its successful, but somewhat slow, Vickers Viscounts
then in service. Vickers and Hunting both started design work on such a plane in
1956, the Vickers being a 140-seat downsizing of their existing VC-10 design
effort then underway as the VC-11, while Hunting's design was an all-new design
for 107 seats.
In 1960, Hunting was merged with Vickers, Bristol, and English Electric to form
BAC. In 1961, BAC management decided to continue work on the then stalled 1-11 project
with internal funding. The short delay was to prove advantageous as the design
was able to use the Rolls-Royce Spey turbofan engines for greatly increased fuel
economy. BAC was concerned that the aircraft was too large to fit the Viscount role
in the original Hunting configuration and, therefore, re-designed it to a smaller
80-seat fuselage known as the Model 200, the original retroactively becoming
the 100.
On May 9, 1961, British United Airways placed the first order for 10 Model 200
aircraft followed on October 23, by an order for 6 from Braniff Airways in the
United States. Other orders soon followed from Mohawk Airlines for 4, Kuwait
Airways for 3 aircraft, and by Central African Airways for 2 aircraft. Braniff
Airways subsequently doubled its order to 12 aircraft while Aer Lingus ordered
4 aircraft. Western Airways ordered 10 aircraft but later cancelled.
In May, 1963, BAC announced the development of the Model 300 and 400. The new
versions used the Mk. 511 version of the Spey with increased power allowing for
more fuel load and, therefore, longer range. There were a number of minor design
changes as well with the main visual difference being to the nose wheel doors.
The original 200 also had a much rounder nose cone which was replaced with a more
pointed one, a change that was later retroactively applied to all 200's as well.
The primary difference between the 300 and 400 was the selection of equipement
and avionics in the cockpit with the 400 intended for sales to the US and,
therefore, equipped with US instruments. This proved to be a shrewd move. American
Airlines ordered 15 aircraft on July 17, 1963, bringing the total to 60 firm
orders plus options for many more, well more than needed for break-even on
the production line.
The prototype, G-ASHG, rolled off the Hurn production line on July 28, 1963,
with the first flight following soon after on August 20. Unfortunately this
aircraft crashed killing all on board on October 22, and an investigation into
the cause led to the discovery of the conditions leading to deep stall when the
airflow over the wing "blanks" the tail, meaning the aircraft loses pitch control.
Although the problem itself seemed not all that simple to solve, BAC added a
stick shaker to avoid the problem in the first place and redesigned the wing's
leading-edge to lessen the impact.
Despite this early setback the flight test program continued and customer
confidence remained high. American Airlines and Braniff Airways both exercised
their options and placed more orders in February, 1964. Further orders were
received from Mohawk Airlines, Philippine Airlines, and from Helmut Horten who
ordered the first Executive aircraft. By the end of 1964, 13 aircraft had rolled
off the production line.
After nearly 2 years of flight testing the aircraft was certified and the first
1-11 delivery, G-ASJI to British United Airways, took place on January 22, 1965.
After several weeks of route proving flights, the first revenue service commenced
on April 9, from Gatwick to Genoa. Braniff took delivery of their first aircraft
March 11, while Mohawk Airlines received their first on May 15. Deliveries
continued and by the end of 1965, 34 aircraft had been received by their customers.
Demand continued to be high and additional orders were received throughout this
period, and a second production line was set up at Weybridge.
In 1967, a larger 119 seat version was introduced as the Model 500 in response
to increasing use of the BEA on short haul routes. 8ft 4in (2.54 m) was added ahead of
the wing, 5ft 2in (1.57 m) behind, the wings were widened by 5 ft (1.5 m), and
the latest Mk.512 version of the Speys were installed. The 500 was not offered
in the US as this market niche was now being filled by the Boeing 727, but it
nevertheless sold in Europe with a major order going to British European Airways.
The final version, the Model 475, combined the smaller Model 400 fuselage with
the higher power of the Model 500, intended for hot-and-high operations. Only a
few were sold.
Total deliveries for 1966, stood at 46 aircraft and between 1967 and 1971, another
120 were delivered. At this point orders slowed but the production line continued
until 1982, with a further 35 aircraft being delivered. The planned Model 670 was
not pursued.
Production continued in Romania as the ROMBAC 1-11, with kits being shipped
for assembly there. The first flight of a ROMBAC 1-11 took place on September 18,
1982, and production continued until 1989, when the 9th airframe was delivered.
The production line had originally intended to deliver up to 80 aircraft but
the deteriorating political situation in Romania closed it early.
Total production for the 1-11, from both British and Romanian factories, was 244
with a further 2 airframes being left incomplete in Romania.
1-11s served widely in the US until displaced by the locally built Douglas DC-9
and Boeing 737 in the early 1970s. In Europe they were a common feature at all
airports and continued in widespread operations until the mid-1980s and into
the 1990s. Many 1-11s then moved to smaller airlines, notably in the far east
and Africa, with the last major operations being in Nigeria where they were
finally grounded after a major crash in 2002.
Models
Model 200 - initial version, widely sold
Model 300 - uprated engines, more fuel for longer range
Model 400 - Model 300 with US instruments
Model 500 - larger version for 119 seats
Model 475 - Model 400 with engines from the Model 500
Model 670 - Model 500's with better fuel economy, only one testbed built
This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia article "BAC 1-11".
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