One of the two prototypes of the Avro VZ-9V Avrocar – CASM negative no 15276

From the Puffalo to the Bisontennial, a brief take on the de Havilland Canada DHC-5 Buffalo

Ever since its creation, in 1967, the Canada Science and Technology Museums Corporation (CSTMC) has collected a great many items connected with this country’s aerospace heritage. On more than one occasion, it has done so with the help of National Research Council of Canada (NRC). A recent example of this cooperation was the acquisition of a truly remarkable engine, the sole surviving Rolls-Royce Spey Mk 801SF in the world.

 

A Rolls-Royce Spey Mk 801SF, quite possibly the one acquired by the Canada Science and Technology Museums Corporation. The engine acquired by the corporation does not have the rotating nozzles visible in the photo – Flight International, 18 May 1972, p. 734

A Rolls-Royce Spey Mk 801SF, quite possibly the one acquired by the Canada Science and Technology Museums Corporation. The engine acquired by the corporation does not have the rotating nozzles visible in the photo – Flight International, 18 May 1972, p. 734

To understand the story behind this turbofan engine, one has to go way back in time, to the mid 1960s. Back then, de Havilland Aircraft of Canada Limited (DHC), a company known today as Bombardier Aerospace Toronto, was a world leader in short take off and landing (STOL) technology. One of the research projects DHC was working on was the so-called Augmentor Wing. To make a long story short, the Augmentor Wing was an integrated propulsion and lift system that combined specially designed jet engines and wings to produce far more lift than a conventional wing. The National Aeronautics and Space Administration (NASA) was sufficiently intrigued to join a United States-Canada research program launched in 1965. Wind tunnel tests with models showed such promise that both countries agreed to fund trials with a suitably modified de Havilland Canada DHC-5 Buffalo twin engined STOL transport plane loaned to NASA. First flown in April 1964, the Buffalo was a more powerful and heavier derivative of the DHC-4 Caribou, an airplane produced to fulfill the military needs of several countries, especially the United States.

 

A de Havilland Canada Buffalo of the U.S. Army near Niagara Falls – de Havilland Aircraft of Canada brochure

A de Havilland Canada Buffalo of the U.S. Army near Niagara Falls – de Havilland Aircraft of Canada brochure

One of the two prototypes of the Avro VZ-9V Avrocar – CASM negative no 15276

One of the two prototypes of the Avro VZ-9V Avrocar – CASM negative no 15276

The DHC engineer in charge of the Augmentor Wing project was Donald Charles Whittley. Back in the late 1950s, this aerodynamicist at Malton, Ontario-based A.V. Roe (Avro) Aircraft Limited, a subsidiary of A.V. Roe (Avro) Canada Limited, itself a subsidiary of British aviation giant Hawker Siddeley Group Limited, was working on the VZ-9V Avrocar, a circular vertical takeoff and landing (VTOL) aircraft funded by the American military. Whittley moved to DHC around July 1962, when Hawker Siddeley sold the Avro Aircraft factory to its second Ontario subsidiary, DHC. Although highly innovative, Canada’s flying saucer, as the Avrocar was sometimes called, did not prove successful, but back to our story.

DHC designed a new wing and new engine nacelles for the Buffalo test plane. In the United Kingdom, Rolls-Royce Limited designed an engine especially for it, using a version of the very successful Spey turbofan engine as a starting point. Rolls-Royce (Canada) Limited of Lachine, Québec, converted two engines for use on the modified Buffalo. The first Spey Mk 801SF (SF for split flow) ran on a test bench in April 1971. The saga of the Spey had begun in July 1959 when Rolls-Royce started to work on an engine to power a new British short range airliner, the de Havilland / Hawker Siddeley Trident. The Spey ran on a test bench in December 1960. It first flew in October 1961, on a modified bomber. The first Trident entered service in March 1964. The Spey was produced in numerous versions that powered both civilian (business jets and short to medium range airliners) and military (attack airplanes, maritime patrol airplanes and supersonic jet fighters) airplanes designed in the United Kingdom and elsewhere. It is one of the most successful medium sized turbofan engines of the 20th century[1].

 

The Augmentor Wing Buffalo – http://ails/arc.nasa.gov/Images/newimages/JPEGs/highres/AC73-2101.jpg

The Augmentor Wing Buffalo – http://ails/arc.nasa.gov/Images/newimages/JPEGs/highres/AC73-2101.jpg

Once DHC and Rolls Royce (Canada) completed their work, Boeing Airplane Company of Seattle, Washington, thoroughly rebuilt the Augmentor Wing Buffalo, as the test plane was called. The world’s first jet-powered STOL transport plane flew on May 1st, 1972. Trials began soon after, in California. The Augmentor Wing Buffalo airplane met or bettered all expectations. It was, however, one very noisy airplane – a serious flaw as far as civilian developments of the concept were concerned.

Months and years went by as testing continued. Back in Ontario, in the 1970s and 80s, DHC prepared the plans of military transport planes and airliners fitted with an Augmentor Wing. None of these was built. The Augmentor Wing Buffalo itself was nicknamed the Bisontennial in 1976, in recognition of the bicentennial of the declaration of independence of the thirteen colonies that formed the core element of the United States. In early 1980, the National Aeronautical Establishment (NAE), an independent division of the NRC, took over control of the Augmentor Wing Buffalo’s operations. The airplane returned to Canada in 1981, not too long after the end of the Canada-U.S. contracts. That same year, the Canadian government gave money to the NAE to continue the trials. The Augmentor Wing Buffalo apparently left the NAE around August 1982. DHC / Boeing of Canada Limited (de Havilland Division), a name adopted in early 1986, kept it until 1989.

Back then, Boeing Company wanted its Ontario subsidiary to concentrate its efforts on the Dash 8 turboprop regional airliner and abandon its work on STOL technology. The certificate of registration of the Augmentor Wing Buffalo was cancelled in September 1989. The airplane itself was scrapped soon after. The outer section of its left wing (1966.0943) went to the National Aviation Museum, today’s Canada Aviation and Space Museum, one of the three components of CSTMC. Oddly enough, the corporation does not seem to have much information on when or how this acquisition was made.

 

QSRA

The Quiet Short-Haul Research Aircraft – http://commons.wikipedia.org/wiki/File:N715NA_(16100297599).jpg

Mind you, the Augmentor Wing Buffalo was not the only airplane of its type involved in research projects. If truth be told, two other Buffalos were converted during the 1970s. The story of one of these began in late 1974 when NASA issued a request for proposal for a Quiet Short-haul Research Aircraft (QSRA). Boeing Commercial Airplane Company of Seattle, Washington, won this competition. It thoroughly modified the Buffalo chosen for the trials, fitting it with a new wing and four jet engines. The QSRA first flew in early July 1978. By and large, the testing proceeded without a hitch. NASA retired the QSRA in March 1994. This historic airplane can be seen in the airpark of the Moffett Field Historical Society Museum, in California.

 

The other research project involving a Buffalo resulted from research initiated by Bell Aerosystems Company, a subsidiary of Bell Aerospace Corporation, in late 1963. The American company’s internally-funded investigation centered upon the use of an air cushion landing gear on airplanes of various sizes. One of the co-inventors of the concept was Thomas Desmond Earl, an aerodynamicist who had left A.V. Roe Aircraft not too long before. Just like Whittley, he had worked on the Avrocar. The air cushion landing gear was tested in August 1967, on a Lake LA-4 four seat amphibian. The concept seemed very promising[2].

The Canadian Armed Forces Buffalo fitted with an Air Cushion Landing System – The Canadian Aircraft Operator, vol. 11, no 8 (May 1st, 1976) : 1

The Canadian Armed Forces Buffalo fitted with an Air Cushion Landing System – The Canadian Aircraft Operator, vol. 11, no 8 (May 1st, 1976) : 1

In late 1970, the U.S. Air Force, Canada’s Department of Industry, Trade and Commerce and the Bell Aerospace Division of Textron Incorporated, a new name adopted around that time, agreed to fund testing of the Air Cushion Landing System (ACLS), as the revolutionary device had become known. As a result, the Canadian Armed Forces provided one of their Buffalos. The modified machine flew around August 1973, with the largest ACLS made thus far – a rectangular doughnut 9.75 m long and 4.25 m wide. Taxi trials with a fully inflated system began in April 1974, with the first take off taking place in March 1975.

The Puffalo or Bell-bottomed Buffalo, as the airplane was nicknamed, proved able to negotiate all sorts of terrain, from water to ice, including areas filled with craters 1.75 m deep. Although fully successful, the trials showed that a great deal of research would have to take place to increase the service life of the rubber and nylon skirt that contained the air cushion of the landing system. The ACLS program ended in March 1977. The Buffalo went back to the Canadian Armed Forces in May. DHC soon returned it to its original condition. This Buffalo still existed as of March 2015. Given the (strong?) possibility that the Department of National Defence will offer a Buffalo to CSTMC at some point in the future, I would like to suggest that the Buffalo formerly equipped with an ACLS be chosen, if it stills exists when the offer is made.

References

[1] In the 1980s, Rolls-Royce (1971) Limited, as the company was then called, began to produce marine gas turbine engines derived from the Spey for use on forty or so warships of the British, Dutch and Japanese navies. The company also produced land based versions of its engine to produce electricity at peak time and push natural gas through pipelines. All of these turbines proved very successful indeed. The most unusual application of the Spey was undoubtedly the ThrustSSC, or Thrust Supersonic Car. Designed by a small British team, this twin engined vehicle reached a speed of 1 223.66 km/h and 1 227.99 km/h in October 1997, over distances of one kilometre and one mile. For the first time ever, a land based vehicle had exceeded the speed of sound.

[2] Interestingly enough, the Lake LA-4 used to test the air cushion landing gear still existed as of early 2015. Better yet, it belonged to a gentleman from Ontario.

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