Avro Canada Chinook
Encyclopedia
The Avro Canada TR.4 Chinook was Canada's first turbojet engine, designed by Turbo Research and manufactured by A.V. Roe Canada Ltd.
Avro Canada
Commonly known as Avro Canada, this company started in 1945 as an aircraft plant and became within thirteen years the third-largest company in Canada, one of the largest 100 companies in the world, and directly employing over 50,000...

 Named for the warm Chinook wind
Chinook wind
Chinook winds , often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies and Great Plains meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest.Chinook is claimed...

 that blows in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

, only three Chinooks were built and none were used operationally. The Chinook was nevertheless an extremely successful design in terms of introducing new concepts and materials, and after being scaled up from 2600 lbf (11.6 kN) to 6500 lbf (28.9 kN), would go on to become one of the early jet age
Jet age
The Jet Age is a period of history defined by the social change brought about by the advent of large aircraft powered by turbine engines. These aircraft are able to fly much higher, faster, and farther than older piston-powered propliners, making transcontinental and inter-continental travel...

's most respected designs, the Orenda
Avro Canada Orenda
The Avro Canada TR.5 Orenda was the first production jet engine from Avro Canada's Gas Turbine Division. Similar to other early jet engines in design, like the Rolls-Royce Avon or General Electric J47, the Orenda nevertheless outperformed its rivals in most ways, and the Orenda-powered Canadair...

.

Development

In late 1942 the National Research Council of Canada
National Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...

 (NRC) sent Dr. J.J. Greene and Malcolm Kuhring to England to report on the various advanced research projects and to see if Canada could play a role in them. One of the team's many topics in the resulting report was an introduction to the work on jet engines being carried out by Frank Whittle
Frank Whittle
Air Commodore Sir Frank Whittle, OM, KBE, CB, FRS, Hon FRAeS was a British Royal Air Force engineer officer. He is credited with independently inventing the turbojet engine Air Commodore Sir Frank Whittle, OM, KBE, CB, FRS, Hon FRAeS (1 June 1907 – 9 August 1996) was a British Royal Air...

 at Power Jets
Power Jets
Power Jets Ltd was a United Kingdom company set up by Frank Whittle for the purpose of designing and manufacturing jet engines.-History:Founded on January 27, 1936, the company consisted of Whittle, Rolf Dudley-Williams, James Collingwood Tinling, and Lancelot Law Whyte of investment bankers O T...

. The Department of Munitions and Supply (DMS) thought this was a wonderful opportunity to get in at the "ground floor" of a newly developing field, one that the country could enter with relative ease and thereby reduce their dependence on foreign suppliers for aircraft engine
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...

s.

In early 1943 a new mission, including Dr. Ken Tupper and Paul Dilworth from the NRC and C.A. Banks of the DMS, left for England specifically to study the jet engine and report on ways that Canada could contribute to the jet effort. The resulting report, known today as the Banks Report, suggested two lines of research. One led from the realization that no one in the nascent industry really understood the effects of real-world weather on the operations of jet engines, especially in icing
Atmospheric icing
Atmospheric icing occurs when water droplets in the atmosphere freeze on objects they contact. This can be extremely dangerous to aircraft, as the built-up ice changes the aerodynamics of the flight surfaces, which can increase the risk of a subsequent stalling of the airfoil...

 conditions. The report suggested forming a research center specifically to study this problem. The report went on to suggest the formation of a private jet engine company.

Almost immediately after they returned to Canada, Dilworth started work on what became the Cold Weather Testing Station in Winnipeg
Winnipeg
Winnipeg is the capital and largest city of Manitoba, Canada, and is the primary municipality of the Winnipeg Capital Region, with more than half of Manitoba's population. It is located near the longitudinal centre of North America, at the confluence of the Red and Assiniboine Rivers .The name...

. They were supplied with an original Whittle W.1, and later a captured Junkers Jumo 004
Junkers Jumo 004
The Jumo 004 was the world's first turbojet engine in production and operational use, and the first successful axial compressor jet engine ever built. Some 8,000 units were manufactured by Junkers in Germany during late World War II and powered the operational Messerschmitt Me 262 jet fighter,...

. Their research demonstrated that water ingestion reduced power by about 20%, not entirely unexpected, but at the same time doubled fuel use, which was a surprise. Further work on the problem led to a number of design elements that would be used on future Canadian jet designs.

While the CWTS was being set up, the government also worked on the second part of the Banks Report, and on 1 July 1944 formally incorporated Turbo Research in Leaside, Toronto. Dilworth returned from CWTS to lead a series of design studies based on the Whittle-style centrifugal compressor
Centrifugal compressor
Centrifugal compressors, sometimes termed radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery.The idealized compressive dynamic turbo-machine achieves a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller...

 design, known as TR-1, TR-2 and TR-3. However, these designs were abandoned in favor of a new axial compressor
Axial compressor
Axial compressors are rotating, airfoil-based compressors in which the working fluid principally flows parallel to the axis of rotation. This is in contrast with other rotating compressors such as centrifugal, axi-centrifugal and mixed-flow compressors where the air may enter axially but will have...

-based design, the TR.4, likely due to their exposure to the Jumo 004. Over the next year the team was built out as more engineers joined the effort, including Winnett Boyd
Winnett Boyd
Winnett Boyd is a Canadian engineer who made major contributions to the development of the jet engine and nuclear reactor design.-Early life and education:...

, Joe Purvis, Burt Avery and Harry Keast from Power Jets. Detailed design was completed in early 1947, and the engine first ran on 17 March 1948.

At the time the Chinook was being designed, Avro had little production capacity and no engine fabrication experience. They farmed out parts manufacture to 1,200 different companies, providing everything from gears and ball bearings, to the compressor and turbine blades. Many of the techniques for fabrication had never been needed in Canada before, and led to a small industrial revolution as they were developed for the project. Among the many advances brought to Canadian industry as part of the Chinook program, Light Alloys Ltd. invested in their first aluminum casting, while Shawinigan Chemicals did the same for stainless steels.

Although the team had already turned to the design of the Chinook's successor, the Orenda, work on the engines continued in order to gain experience in construction and operation. Frank Whittle personally viewed the engine in 1948. Only six sets of engine parts were made, from these three complete engines and one compressor section were completed. By October 1949 the engines had run over 1,000 hours and had improved to over 3,000 lbf (1,360 kg) thrust.

Design

Designing on the basis of a theoretical twin-engine fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

, seemingly similar to the Messerschmitt Me 262
Messerschmitt Me 262
The Messerschmitt Me 262 Schwalbe was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems prevented the aircraft from attaining operational status with the Luftwaffe until mid-1944...

, the TR-4 design was in many ways an analog of the Jumo 004. The primary difference in design was the use of six separate flame cans instead of the singular annular combustor of the Jumo. Compared to the Jumo the Chinook was smaller and lighter; it was about the same diameter, 20 inches shorter, and over 300 lb (136.1 kg) lighter. In spite of this it produced almost double the thrust, largely due to the improved materials, especially in the turbine, which allowed for higher operating temperatures.

The Chinook's compressor consisted of nine axial stages. The first two were made of stainless steel to help with debris but the remaining seven stages were made of aluminum alloy. These were attached to hubs that were also primarily made of aluminum, except the ninth disk, which was steel. Behind the compressor were the six straight-through flame cans, exiting onto a single-stage steel turbine. The final exhaust gas temperature was 650 degrees Celsius. Air cooling for the turbine was provided by a series of six tubes running from the middle of the compressor to the turbine, lying between the flame cans, which exited in front of the turbine face. An accessories section was powered off a shaft at the front of the engine at the main bearing. The front main bearing was located under a prominent nose cone that extended well out in front of the engine. An oil tank was "wrapped" around the engine at about the 4 o'clock position, as viewed from the front.

Specifications

External links

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