Fokker F27 Friendship


The Fokker F27 Friendship is a turboprop airliner developed and manufactured by the Dutch aircraft manufacturer Fokker. It is the most numerous post-war aircraft manufactured in the Netherlands; the F27 was also one of the most successful European airliners of its era.
The F27 was developed during the early 1950s with the intent of producing a capable successor to the earlier piston engine-powered airliners that had become commonplace on the market, such as the Douglas DC-3. A key innovation of the F27 was the adoption of the Rolls-Royce Dart turboprop engine, which produced substantially less vibration and noise which provided improved conditions for passengers; another major comfort feature was cabin pressurisation. Innovative manufacturing techniques were also employed in the aircraft's construction.
On 24 November 1955, the F27 made its maiden flight; on 19 November 1958, the type was introduced to revenue service. Shortly after its introduction, the F27 was recognised as being a commercial success. Under a licensing arrangement reached between Fokker and the U.S. aircraft manufacturer Fairchild, the F27 was manufactured in the United States by the latter; Fairchild went on to independently develop a stretched version of the airliner, which was designated as the Fairchild FH-227. During the 1980s, Fokker developed a modernised successor to the F27, the Fokker 50, which eventually replaced it in production.

Design and development

Origins

In the aftermath of the Second World War, twin-engine all-metal monoplanes such as the successful Douglas DC-3 airliner dominated commuter aviation. Over 10,000 DC-3s had been manufactured during wartime, which led to the type being highly available and thus encouraging its adoption by hundreds of operators across the world.
By the early 1950s, various aircraft manufacturers had begun considering the post-war requirements of the civil aviation market and several commenced work upon projects aiming to produce designs for new aircraft which would be viewed as best meeting these requirements; Dutch firm Fokker was amongst the companies pursuing development of such an aircraft. By 1951, figures within Fokker were urging that design work be undertaken on a prospective 32-seat airliner intended as a direct replacement for the popular DC-3. Fokker sought the opinions of existing DC-3 operators on what performance increases and refinements they would expect of a new model of commuter aircraft. On the basis of this feedback, the design team chose to incorporate various new technologies into the tentative design.
Fokker evaluated several potential configurations for the airliner, including the use of Wright Cyclone radial engines, before finally settling upon a high-wing aircraft, which was furnished with a pair of Rolls-Royce Dart turboprop engines and a pressurised cabin which contained a total of 28 passengers. The Dart engine had already proven successful on the early models of the Vickers Viscount, while a high-mounted wing had been selected as it produced a higher lift coefficient than a lower counterpart, it also enabled easier ground loading due to a lower floor level and provided unfettered external views to passengers without any weight increase. In the aircraft's construction, Fokker used an innovative metal-to-metal bonding technique, Redux, resulting in a longer fatigue life, improved aerodynamics, and a lighter structure; Fokker became the first such company after de Havilland to employ such means.
In 1953, the proposed airliner received the name Friendship. A total of four prototypes were produced, two of these being flyable aircraft that were used for the test flight programme and were paid for by the Netherlands Institute of Aircraft Development; the other two prototypes were for static and fatigue testing. On 24 November 1955, the first prototype, registered PH-NIV, performed its maiden flight. The second prototype and initial production machines were 0.9 m longer than the first prototype in order to addressing a revealed tendency for slightly tail-heavy handling as well as to provide additional space for four more passengers, raising the maximum number of passengers which could be carried to 32. These aircraft were also powered by the Dart Mk 528 engine, which was capable of generating greater thrust.

Further development

Throughout the F27's production life, Fokker proceeded to adapt the design for various purposes and roles. Via modifications such as the adoption of improved engines, rearranged loading doors, elongated fuselages, and other changes, several different models of the F27 were developed and made available for commercial operators. Several military transport models were also produced. Fokker also chose to design a dedicated model of the F27 for conducting maritime reconnaissance missions.
During 1952, Fokker established a relationship with the US aircraft manufacturer Fairchild, which was interested in the upcoming F27. In 1956, Fokker signed a licensing deal with Fairchild, under which the latter was authorised to manufacture the F27 in the USA. On 12 April 1958, the first American-built aircraft conducted its first flight. Production of Fairchild built aircraft would continue until July 1973. Fairchild proceeded to independently develop a stretched version of the airliner, designated as the FH-227. The majority of sales completed by Fairchild fell within the North American market.
In the early 1980s, Fokker decided to develop a modernised successor to the F27 Friendship, designated as the F27 Mark 050 and marketed as the Fokker 50. Although originating from the F27-500 airframe, the Fokker 50 was virtually a new aircraft, complete with Pratt & Whitney Canada engines and modern systems, which led to its general performance and passenger comfort being noticeably improved over the F27. The Fokker 50 ultimately replaced the F27 in production.

Operational history

In November 1958, the first production aircraft, an F27-100 model, was delivered to Irish airline Aer Lingus; it performed its first revenue flight in the following month. Other early customers of the Friendship included Braathens SAFE and Luxair in Europe; New Zealand National Airways Corporation; Trans Australia Airlines and its Australian competitors Ansett and East-West Airlines; and Turkish Airlines.
Initial sales for the type were slow, which led to Fokker seeking financial support from banks and from the Dutch government in order to maintain production of the airliner while more customers were sought. In 1960, demand for the F27 increased rapidly as multiple airlines placed sizable orders for the type. This is in part due to the spreading reputation of the type, having been found by operators that, in comparison to its piston-engine wartime counterparts like the DC-3, the F27 possessed superior levels of efficiency, enabling faster flight times, greater passenger comfort and a higher level of reliability.
In 1960, the base purchase price for an RDa.6-powered F27 was £239,000. By the end of the production run for the Fokker F27 in 1987, a total of 592 units had been completed by Fokker, more than any other western European civil turboprop airliner at the time.
In later service, many aircraft have been modified from their original configurations for passenger service to perform cargo or express-package freighter duties instead. The last major cargo user of the F27 in the United States was FedEx Express, using it as a cargo "feeder" aircraft. These were retired and replaced by a mixture of ATR 42 and ATR 72 aircraft by the end of 2009, the last of these aircraft were subsequently donated to the Hickory Aviation Museum.
As of July 2010 a total of 65 F27s were in commercial service with almost 30 different airlines. By July 2013, only 25 Friendships remained in service, operated by 13 different airlines; most of these were F27-500s, with two -400s and a solitary -600 series aircraft in service. Italian cargo airline MiniLiner operated six F27s and Air Panama had four in its fleet. The United States Army Parachute Team has operated a single C-31A Troopship for conducting its skydiving exhibitions since 1985. As of July 2018, 10 aircraft remain in service operated by 7 airlines.

Variants

Notable accidents and incidents

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;Iceland
;Netherlands
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;Norway
;United Kingdom
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Citations