Page 26 - Volume 11 Number 1

Although no one at the time could have known about the ramifications of Riley’s decision, it marked a critical first step toward uniting PWC and the Beech Aircraft Corporation. The chief question that emerged from a series of discussions centered on what type of engine would help make PWC one of Canada’s major engine manufacturers. The primary builders of gas turbine engines in the country at that time were Orenda and Rolls­Royce. Riley wanted to transition PWC from its long­ standing function as a service and support provider for PWA, to designing and building engines of its own design.
“We were determined to reverse the picture as it existed in Canada with Orenda and Rolls­Royce as the big names. Riley and I looked at a variety of areas that could launch PWC into new product development. In the end, we decided to focus on a small gas turbine engine,” said engineer R.H “Dick” Guthrie.1 Riley’s initiative was a bold one, but as Hugh Langshur, PWC’s chief engineer remembered, he was “surprised that we were allowed to enter the gas turbine business without being led by a ‘big name.’” He recalled that there were only two potential sources that employed men with the necessary experience – Canada’s National Research Council (NRC) and Orenda.2
By June, six engineers had been hired: Doug Millar and Elvie Smith were wooed away from the NRC, followed by another NRC engineer, John Vrana. The other three – Pete Petersen, Allan Newland and J.P. Beauregard – bade farewell to good jobs at Orenda for an uncertain future with PWC. “We were all excited about working at PWC, but aware that it was a gamble,” Peterson recalled. The last few engineers, Ken Elsworth, Gordon Hardy, Fred Glasspoole, Fernand Desrochers, Arthur Goss and Jim Rankin, joined the team in the summer of 1957.3
Part of the team were transferred to PWA’s headquarters in Hartford, Connecticut, to begin design studies on a small, lightweight engine. That same year the RCAF released specifications for a new jet trainer, and Canadair offered the CL­41 Tutor – a single­engine design featuring side­by­side seating for student pilot and instructor. Officials at PWC immediately recognized the opportunity to supply an engine. The team worked feverishly on a configuration that featured an axial compressor section and would produce 3,000 pounds static thrust. Initially designated the DS­3J, the engine was redesignated as the FDS­4J and eventually the JT­ 12. It is important to note that in addition to military applications, the DS­4J also showed promise as an engine for business aircraft.4
Throughout the second half of 1957, the Canadian en­ gineering team in Hartford continued to work on the jet until early in 1958 when PWA assumed responsibility for the project. The primary reason for the shift was simple: PWC lacked the money, manpower and facilities to com­ plete the job. That decision, however, would prove to be providential for Canada and Beech Aircraft Corporation.
24 • KING AIR MAGAZINE
Free to begin work on another small gas turbine, the team reassembled in Longueuil began a number of preliminary design studies, but further progress was slowed until PWC conducted a survey to determine if a market existed for such an engine, and if so, what power range was required. Finally, in July of 1958 the decision was made to focus on a series of turboprop powerplants in the 200­2,200 shp class, including an emphasis on engines rated at 250­500 shp.
These engines seemed best suited to small, single­ and twin­engine private and business aircraft built by airframe manufacturers Piper Aircraft Corporation, Cessna Aircraft Company and the Beech Aircraft Corporation. A series of meetings were held between PWC and all three companies. Cessna, of course, already had extensive experience with gas turbines in the T­37 jet trainer, of which hundreds had been delivered to the U.S. Air Force since 1955. Piper officials were not keen on turbine engines, but Beech Aircraft management was interested in “turning to turbines with all possible speed,” according to a PWC official. Both engineering and marketing at Walter H. Beech’s company were certain that the “future of the light aircraft lay with turbines, especially turboprops, and was ready to install an engine as soon as it was available.”5
Although CEO Olive Ann Beech believed in a “go slow” approach to technical innovation and new aircraft designs, she realized that the company could not afford to rest on its past successes and remain on the leading edge of development in business aircraft. Engineering already had made preliminary plans to mate a turboprop in the 450­shp class to a next­generation Beechcraft based largely on the successful Model 50 Twin Bonanza (that “next­gen” airframe would become the Model 65 Queen Air). In addition, turboprop engines were being tested in France on the venerable Model 18, and those experiments were being closely monitored by the company.
As 1958 came to an end, the chief issue facing Dick Guthrie’s design team was choosing a configuration for the new engine. Key factors affecting that choice included reliability, cost, specific fuel consumption, weight and maintainability. Two concepts finally emerged – free turbine and fixed­shaft. Members of the team freely debated the merits of both – a fixed­shaft would cost less to build, but the free turbine had a few distinct advantages every King Air pilot should be thankful for: less power required to start the engine, less complex fuel controls, and in the case of one engine becoming inoperative, only a part of the engine would freewheel with the propeller feathered, creating less drag.
In addition, the engine could use existing propellers, obviating costly development of a propeller designed specifically for a fixed­shaft turbine. One other advantage of the free turbine design is that the engine’s gas generator typically operates at about 35,000 rpm and the
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