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.
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.
Canadair North Star