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  • Weird and wonderful - flying testbeds
    Posted by Guy Norris 10:21 PM on May 21, 2010

    Following my flight in Honeywell’s 757 flying testbed, I thought it would be interesting to post a few images of other, earlier aircraft in this role. The use of flying testbeds, particularly for propulsion research and development, exploded during World War II and its immediate aftermath. Notable early examples included the Boeing B-17, several of which were converted for engine testing. The first was a B-17G used by Wright Aeronautical to test the XT35 Typhoon – an early turboprop, as well as the XJ65 turbojet.

    blog post photo
    ww2aircraft.net

    The four-engined Avro Lancaster was pressed into service as a testbed in 1943 for evaluation of the Metrovick turbojet, and the later Lancastrian variant (below), was extensively used for early jet tests. Here a Lancastrian flies with Rolls-Royce Nene 1s in the outboard positions. Lancs also flew with Rolls-Royce Avons, de Havilland Ghosts and Armstrong Siddeley Viper and Mamba engines amongst others. They also found similar testbed roles in Canada and Sweden.

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    www.lancaster-archive.com


    Orenda of Canada leased a Boeing B-47B from the U.S. Air Force to test the 20,000lb Iroquois turbojets for the Avro CF-105 Arrow. The modification to attach the 30-ft long test nacelle was performed by Canadair in Montreal. The Boeing was assigned a Canadian military designation, the CL-52, and was the only B-47 ever to serve for a foreign air force.

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    (Ian Bell collection)

     

    Bristol Siddeley were allocated an Avro Vulcan B1 bomber to flight test the Olympus 22R for the proposed TSR2. The aircraft was later destroyed when a low pressure compressor drive shaft failed in the test engine, resulting in the sudden ejection of the LP turbine disk and an uncontrollable fire.


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    (Ian Bell collection)


    A Vulcan was also used to test the later Olympus 593 for Concorde. Pictured here at Filton, UK, the Vulcan test phase was particularly vital for inlet design refinement.

      
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    www.transportarchive.org.uk

    P&WC used a CF-100 interceptor on loan from the Canadian forces to flight test the JT15D during its early development.

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    (Ian Bell collection)

    P&WC used a Vickers Viscount 757 (C-FTID-X) for PT6A-50 development testing. This aircraft, originally delivered to Trans-Canada Air Lines in March 1959, was bought by P&WC for engine testing from Air Canada in 1972. It was later modified to test the PT7 (which P&WC renamed the PW100). This photo shows the PW117 engine under test mounded in a production EMB120 nacelle.


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    (Ian Bell collection)

     

    P&WC’s soon-to-be retired ex-American Airlines Boeing 720-023B configured with its distinctive nose adapter in place to test turboprops – in this case the PW120. A side-mounted test strut was also fitted to enable testing of turbofans. With an inlet cover installed on the side engine this configuration allowed P&WC to test a turboprop and leave the fan engine installed for additional testing once the turboprop was completed, says Honeywell (former P&WC) test engineer Ian Bell. “The weight and balance was tricky and we actually used the fuel in the number 1 and number 4 wing reserve tanks as ballast.”

     
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    (Ian Bell collection)

     

    Honeywell’s Boeing 720B, formerly in service with TWA, Northwest and Maersk Air, is shown flying with an HTF7000. Sadly, the aircraft was broken up when the 757 was acquired.

    blog post photo
    (Ian Bell collection) 

    Rolls-Royce leased a type 1106 VC10 from the RAF for flight testing of the RB211 then in development for the Lockheed L-1011 TriStar. The test crew had a close call in May 1972 when the cold stream thrust reverser on the RB211 became unlocked and deployed in-flight at 20,000 ft. Fighting adverse yaw and roll, and descending at 2,500 ft per minute, the crew dumped fuel and arrested the descent at 1,000 ft before managing to limp back for an emergency landing.


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    (Ian Bell collection)

     

    General Electric acquired a 707-321 to test the CFM56 in 1983. Originally delivered to Pan Am as ‘Clipper Bald Eagle’ in April 1960, the aircraft subsequently passed through a long series of operators including Donaldson Airlines, British Midland, Syrian Arab, Tunis Air, Kuwait Airways, Kenya Airways, and Pakistan International Airways. The aircraft was scrapped in the 2000s, several years after GE transitioned flight test work to its ex-Pan Am 747-100.

     
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    General Electric


    …and finally, here’s a sight you don’t see everyday! The first afterburner flight test of the former Garrett/AlliedSignal TFE1042 (a military engine developed for Taiwan’s Ching-Kuo Indigenous Defense Fighter) on the company’s Falcon 20 testbed – pictured in March 1988.


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    Honeywell

    Tags: tw99, testbeds, Boeing, B-17, B-47, 720, 707, CF-105, Vulcan, Concorde, CF-100, Viscount, VC10, L-1011, Falcon 20

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