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.

The 1-11 was designed to replace the already wildly successful Vickers Viscount on its existing routes with British European Airways (BEA), and was also very successful with the many other operators of the 400+ Viscount fleet. The 1-11 was the second short-haul jet airliner to enter service, the first being the famous Sud Caravelle, but due to the 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 very popular, with a huge 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 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 originally 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 it was 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 mode; American Airlines ordered 15 aircraft on the 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.

Depite 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 short-haul routes. 8ft 4in (2.54 m) 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 to 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 proceeded with.

Production then 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 18th, 1982, and production continued until 1989 with 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.

1-11's 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

Specifications

For BAC 1-11-200:

Length: 92ft 6in (28.2 m)

Span: 88 ft 6in (26.9 m)

Height: 23ft 9in (7.2 m)

Wing area: 1,003 sq ft (93.2 mē)

Empty weight: 46,405lb (21049kg)

Max takeoff weight: 74,500 lb (33793 kg)

Cruise speed: 495 mph (795 km/h)

Maximum speed: 541 mph (870 km/h)

Range: 1,439 miles (2,315 km)

Service ceiling: 35,000 ft (10.668 m)

Engines: 2x Rolls-Royce RB.163 Spey Mk. 506, 10,600 lb (47 kN) thrust each

Accommodations: 2 crew, 3 attendants, 89 passengers in charter layout

For BAC 1-11-300 and -400, same as -200 with these exceptions:

Range: 1,854 miles (2,982 km)

Engines: 2x Rolls-Royce RB.163 Spey Mk. 511, 11,400 lb (51 kN) thrust each

For BAC 1-11-500:

Length: 107 ft (32.6 m)

Span: 93 ft 6 in (28.5 m)

Height: 24 ft. 6 in (7.5 m)

Wing area: 1,031 sq ft (95.8 m²)

Empty weight: 54,900 lb (24902 kg)

Max takeoff weight: 104,500 lb (47400 kg)

Cruise speed: 495 mph (795 km/h)

Maximum speed: 541 mph (870 km/h)

Range: 1,707 miles (2,745 km)

Service ceiling: 35,000 ft (10,668 m)

Engines: 2x Rolls-Royce RB.163 Spey Mk. 512DW, 12,550 lb (5,693 kg) thrust each

Accommodations: 2 crew, 3 attendants, 119 passengers in charter layout