The Avro Canada TR-5 Orenda was the first production jet engine from Avro Canada's Gas Turbine Division. The Orenda outperformed its rivals in most ways, and the Orenda-powered Canadair Sabres were among the fastest of all first-generation jet fighters. Over 4,000 Orendas of various marks were delivered during the 1950s, Avro's greatest engine success.
Development
The Orenda design started in the summer of 1946 when the RCAF placed an order with Avro Canada for a new night/all-weather fighter. To power the design, Avro decided to build their own engines. Avro had recently purchased Turbo Research, a former crown corporation set up in Toronto, to develop jet engines. Turbo Research was in the midst of designing their first engine, the 3,000 lbf (13 kN) TR.4 Chinook, which could easily be scaled up for the new fighter design.
Avro's newly christened Gas Turbine Division started work on the larger 6,000 lbf (27 kN) thrust in autumn 1946, and the design work was completed in January 1948, just prior to the first run of the Chinook on 17 March 1948. The TR-5 was named "Orenda", an Iroquois word meaning "Tribal Soul on the Right Path".
Progress on the Orenda was rapid with parts arriving in 1948, and the engine was run for the first time on 8 February 1949. Avro was so confident of the design that they invited high-ranking officials from the RCAF and Canadian government to witness this very first test. On 10 May the engine reached its design thrust of 6,000 lbf (27 kN). At the time, it was the most powerful jet engine in the world. The Orenda passed a total of 2,000 hours by 10 February 1950. After modification by July it had passed 3,000 hours.
Flight testing started with a converted Avro Lancaster. The two outboard Merlin engines were replaced with the Orendas, and the new aircraft took to the sky on 10 July 1950. The aircraft ran up 500 hours by July 1954, when this portion of flight testing ended.
Production
The Orenda 2 was the first production model, passing its qualification tests in February 1952. The engine was fitted to the Avro CF-100 and flown on 20 June 1952, with a squadron of pre-production Mk.2 aircraft entering RCAF service on 17 October.
The first real production model was the Orenda 8, which was the powerplant of the CF-100 Mk.3 that entered service in 1953. This was soon followed by the Orenda 9 powered Mk.4 that flew on 11 October 1952, and then by the rocket-armed Mk.4A with the 7,400 lbf (33 kN) Orenda 11. The 11 would be the primary production version for the CF-100, powering the Mk.4A and all future versions, with over 1,000 engines produced.
Design
The Orenda was fairly conventional in layout, built in three main parts; compressor, combustion area, and turbine/exhaust.
At the front was the compressor section, containing the ten-stage compressor housed in a tapering magnesium alloy shell. The nose cone held the electric starter motor, which acted as a generator once the engine was up and running.
The compressor had ten axial stages of mixed steel and aluminum construction. In the original Orenda 8, 9 and 10's this operated at a 5.5:1 compression ratio. The hub consisted of three aluminum disks carrying the first nine stages, and a steel disk bolted onto the end carrying the tenth. The central casing held the power shaft and was made from magnesium alloy. Around it were the six flame cans. The turbine was made of solid Inconel blades attached to an austenitic steel hub. The blades were air cooled by bleeding off compressed air from the fifth compressor stage and piping it to the turbine face, the six pipes lying between the flame cans. The exhaust section consisted of welded steel sheeting.
Orenda 1: original prototype models, 6,000 lbf (27 kN)
Orenda 2: first production model
Orenda 3: An Orenda 1 modified for installation in a North American F-86A Sabre, becoming the first Orenda to fly under its own power
Orenda 8: improved reliability, 6,000 lbf (27 kN)
Orenda 9: improved thrust, 6,500 lbf (29 kN), required some changes to the nacelles
Orenda 10: Orenda 9 adapted for the Sabre
Orenda 11: main production version for the CF-100, 7,400 lbf (33 kN)
Orenda 11R: with afterburner
Orenda 14: similar to the 7,500 lbf (33 kN) Orenda 11, used on both the CF-100 and Sabre
Orenda 17: combined the compressor from the 9 with the turbine of the 11, along with an afterburner 8,490 lbf (37.8 kN) wet
(Wikipedia)
