Trans-Canada Air Lines (TCA), the
Royal Canadian Air Force (RCAF),
Canadian Pacific Airlines (CPA) and
British Overseas Airways Corporation (BOAC) were the principal operators of the "
North Star", with the CPA examples known as the "
Canadair Four" and
BOAC examples known as the "
Argonaut".
RCAF service The RCAF North Stars were unpressurized and were used on a variety of transport duties. Like other North Stars, they were notorious for the high level of cabin noise caused by the Merlin engines, as unlike the radials of the DC-4, the exhaust from the individual cylinders is not collected and exhausted via a single outlet, but instead exits the separate individual ejector-exhaust stubs in high-pressure bursts. In an effort to reduce cabin noise, the sole C-5 variant was powered by
Pratt & Whitney R-2800 Double Wasp engines that were considerably quieter. The only C-5 was delivered to the RCAF in 1950, entering service with
No. 412 Transport Squadron RCAF in Uplands, Ottawa, specially outfitted for the transportation of VIP passengers. It was used to transport the Canadian Prime Minister,
the Queen, and numerous other dignitaries on various high-profile missions, serving faithfully for 17 years, later becoming a crew trainer before being retired and sold in the United States. North Stars were also employed by 412 Squadron RCAF on various VIP transport duties and, overall, the aircraft provided valuable and reliable long range transport services for the RCAF. From 1950 to 1952, during the
Korean War, RCAF North Star aircraft were employed ferrying supplies to Korea across the
Pacific Ocean. They flew 599 round trips over the Pacific and delivered seven million pounds of cargo and 13,000 personnel on return trips. They flew 1.9 million miles without a fatal crash. After 1967, the remaining North Stars were assigned to
No. 426 Transport Squadron RCAF initially deployed to
Dorval, Quebec and then to
Trenton, Ontario. Gradually, their service life diminished in the 1970s and most were declared surplus.
TCA and BOAC operations TCA received its fleet of twenty DC-4M-2 North Stars during 1947 and 1948 and operated them on routes within Canada and to the USA until 1961. Starting in 1954 the North Stars were replaced on TCA's routes to Europe by
Lockheed Super Constellations. To deal with passenger complaints about noise, TCA engineers developed a cross-over for the fuselage-side exhausts that reduced cabin noise by 6-8 decibels. "In the cabin, noise is reduced to 102 decibels near the windows and 93 at the aisle." BOAC ordered 22 DC-4M-4s and named them the "
Argonaut class", each aircraft having a classical name beginning with "A". The Argonauts were delivered between March and November 1949; they flew to South America, Africa, the Middle East and the Far East from
London Heathrow Airport until 1960. On 1 February 1952 the BOAC Argonaut
Atalanta G-ALHK transported Princess Elizabeth and the Duke of Edinburgh to Kenya to begin a Commonwealth tour. Some days later, 6 February, it was again
Atalanta G-ALHK which returned the newly acceded Queen Elizabeth II to England upon the death of her father, King George VI.
Rolls-Royce also developed a quieter 'cross-over' exhaust system for the DC-4M, the modifications being supplied in a kit allowing installation on the aircraft by the operator. The engine thus modified became the 'Merlin TMO' in contrast to the unmodified engine, the Merlin TML - Transport Merlin L. The modified exhaust conferred an increase in horsepower over the unmodified system of 38 hp, resulting in a 5 knot improvement in true air speed. Sound levels were reduced by between 5 and 8 decibels. Still air range of the aircraft was also improved by around 4 per cent. BOAC
Argonauts initially, due to schedules being unable to be changed, had only the inner engines so-modified, the remaining outer engines being changed to the new exhaust system when time was available.
Later service After service with TCA and BOAC, the surplused North Stars and Argonauts had long careers with secondary operators such as
British Midland Airways, Overseas Aviation and other charter companies. Cargo conversions of available airframes also lengthened the service life of Argonauts and North Stars.
CF-UXA, ex-RCAF
17510 was the last DC-4M in airline service, completing its final flight on 19 June 1975 at
Miami,
Florida. Despite the onset of
jet airliners in the 1950s, the rugged Canadair North Star found a niche in both military and civil use. ==Variants==