The Canadair CP-107 Argus (company designation CL-28) is a maritime patrol aircraft designed and manufactured by Canadair for the Royal Canadian Air Force (RCAF).
In its early years, the Argus was reputedly the finest anti-submarine patrol bomber in the world.
The Argus served throughout the Cold War in the RCAF’s Maritime Air Command and later the Canadian Force’s Maritime Air Group and Air Command.
In 1949, Canadair recognized that the RCAF would soon be looking for a replacement for the Avro Lancaster’s being used in the maritime patrol role and proposed the CL-29, a variant of the North Star, itself a variant of the Douglas C-54 Skymaster or DC-4 transport.
When the RCAF issued the specification in 1952, it was for a larger and more capable aircraft, and two proposals were received.
These included a Lockheed Constellation variant from Lockheed, however its low speed handling was deemed inadequate by the RCAF, while Bristol proposed a variant of their Britannia airliner but concerns were raised over its floating controls, where they were controlled via servo tabs rather than direct linkages.
The RCAF preferred the Bristol proposal, but it would be developed in Canada.
Canadair presented two proposals, the CL-28 also based on the Britannia, which was accepted, and a lowest cost design called the CL-33 which was described as a fat Lancaster.
It would have comparable to the Avro Shackleton already being operated by the RAF, but significantly lighter, and was to be powered by the same engines as were used in the CL-28, or similar radial engines.
Canadair began work on the CL-28 in April 1954 and at the time it was the largest aircraft to be built in Canada.
The hybrid design, initially referred to as the Britannia Maritime Reconnaissance, or Britannia MR, was derived from the Bristol Britannia airliner, having the same wings, tail surfaces and landing gear except for being Americanised, meaning that it used the same general design, but changed from British materials, dimensions and standard parts to American ones.
Due to the greater stresses from flying at low altitude for long periods of time, even the components taken from the Britannia needed substantial reinforcement, and to meet these demands, extensive use of a locally developed metal to metal bonding was used.
The Argus represented the first large scale use of titanium in the structure, as well as structural plastic, which was used to electrically insulate the top of the fin for the sensors mounted there.
The fuselage was completely redesigned by Canadair, going from the pressure cabin used in the Britannia to an unpressurised one with two 18 ft (5.5 m) long bomb bays fore and aft of the wings.
The powerplants were also changed from the Bristol Proteus turboprop engines to Wright R-3350 turbo-compound piston radial engines, which had lower fuel consumption necessary for extended missions at low level.
132 ft 4.5 in (40.348 m)
142 ft 3.5 in (43.371 m)
40 ft 9 in (12.42 m)
2,075 sq ft (192.8 m2)
81,000 lb (36,741 kg)
Max take-off weight
157,000 lb (71,214 kg)
6,640 imp gal (30,200 l; 7,970 US gal)
4 × Wright R-3350 TC18EA1 18 cylinder Turbo-Compound air-cooled radial engines, 3,700 hp (2,800 kW) each
3-bladed Curtiss-Wright Electric C634S-C554 metal variable-pitch propeller, 15 ft 6 in (4.72 m) diameter
315 mph (507 km/h, 274 kn)
207 mph (333 km/h, 180 kn)
5,900 mi (9,500 km, 5,100 nmi)
25,000 ft (7,600 m)
(Maximum load of 8,000 lb (3,600 kg))
Mark 30, Mark 43 mod 0, Mark 44 and Mark 46 torpedoes.
350 lb (160 kg) Mark 54 depth bombs and practice bombs.
Mark 400 Signal Underwater Sound Charges (SUS).
LUU2/B 2 million candle power parachute flares.
(maximum 3,800 lb (1,700 kg))
The Argus carried out trials for AGM-12B Bull pup air-to-surface missiles and 2.75 inch Folding-Fin Aerial Rockets (FFAR) but these were never used operationally.