Canada has long had a robust aerospace industry, building not just small utility planes like DeHavilland of Canada is famous for, but also medium sized transport aircraft, and military aircraft. One such military aircraft was the CP-107 Argus maritime patrol plane. In the early 1950s, The Royal Canadian Air Force operated three squadrons of the US built Lockheed P2V Neptune. The Neptune was a fine aircraft, but with the vast coastlines and expanses of waters off Canada, the RCAF wanted something more, and with greater endurance and more space for sensors and weapons.
Starting a design from scratch was beyond Canada’s capability and budget, but building a derivative of an existing design was a real possibility. At the same time, the RCAF was also interested in long range transport aircraft. And if you watched yesterday’s video about British aviation, you know one of the aircraft of the time was the turboprop powered Bristol Britannia. The nice roomy fuselage and excellent range were very appealing to the RCAF. And so Canadair acquired a license to build the Britannia.
But the Britannia was built to fly high, and relatively fast. A sub hunting maritime patrol plane needed to spend a great deal of time flying very low, and quite slow. The Bristol Proteous turboprop engines of the Britannia were efficent at altitude, but quite thirsty near sea level. Further, since low and slow was the order of the day, the pressurized fuselage wasn’t needed. What was needed was a pair of bomb bays.
Canadair redesigned the fuselage as unpressurized and with the two large bays. As for the powerplants, they took what might be seen as a technological step backward. They switched from turboprops to piston engines.
The Wright R-3350 was initially something of a nightmare when first flown in the early 1940s, with a bad habit of bursting into flames. But by the early 1950s, it was much improved, with great reliability, and through the magic of Turbo-Compound, was quite efficient at low altitude.
Equipped with either the US APS-20 surface search radar, or the British made ASV-21, and with a Magnetic Anomaly Detector tail boom, the Argus also used sonobouys, radio direction finding and other measures to hunt for Soviet submarines.
The Argus entered RCAF service in 1957 and was retired in 1981, replaced by the CP-140 Aurora, a Canadian variant of the US P-3 Orion. As a child, I can recall seeing the occasional Argus visiting NAS Whidbey either for training or for airshows.
Given that the Argus is about the size of a B-29 Superfortress, building one was quite the industrial achievement, and the Canadians were quite proud of their accomplishment, so much so they produced a 30 minute film showing how it was done.