The Becoming of the CL-44
It all started with The Argus
In 1949 had Canadair the idea to offer the RCAF a new maritime Patrol Aircraft to replace the ageing Lancaster fleet. Canadair thought using the North Star, a Canadian version of the DC-4, as a platform. When the RCAF issued their specifications in 1952 it was clear that the requirements could not be met with the North Star. At the same time Lockheed submitted a version of the Super Constellation as and Bristol submitted a version of the Britannia 100 Turboprop Airliner.
The RCAF discarded the Constellation since it could not manoeuvre safely at low speeds and low altitudes. The Britannia was favorised especially after the possibility was investigated to built one plane that could do maritime patrol and ASW tasks.1953 the RCAF decided on the Britannia. On February 23, 1954, Ottawa announced that Canadair would build the plane and on March 13 the licence agreement was signed. On May 27 the government awarded Canadair a contract to produce 13 maritime patrol/ASW aircraft based on the Bristol Britannia. It was designated Canadair CL-28 ARGUS.The Argus retained the Britannia's wings, tail and the tab based flight control system. The fuselage was redesigned to accommodate two weapon bays, a forward crew compartment and a transparent nose. The turboprop engines where not considered ideal for low altitude operations, so the designers replaced the Britannia's Proteus turboprops with 3700 bhp Wright R-3350 turbo-compound piston engines to provide the combination of high power and low fuel consumption. The Argus was equipped with latest in avionics and ASW. They ran of a fully paralleled AC electrical system. The aircraft was the first in history to synchrophase four 400-cycle systems in an aircraft. The first Argus made its first flight on 28 March 1957. The Argus flew with 404 and 405 Sqd at Greenwood, Nova Scotia; 415 Sqd at Summerside, Prince Edward Island; and 407 Sqd at Comox, British Colombia. It was a reliable and good aircraft. For many years it was the most advanced ASW aircraft in the world. The Argus served for 24 years and during this time only 2 of the 33 Arguses built were lost. 20727 of 404 Squadron crashed near Puerto Rico during night exercise on March 25 1965. 10737 crashed on landing at Summerside on March 31, 1977 when it collided with a Lockeed Electra, which Canadair had modified for Ice reconnaissance work.The last operation work took place on November 10 1980. In 1982 Bristol Metal Industries of Toronto bought 24 Arguses and melted them down on the spot. It was argumented that the Canadian government did not want them to fall into the wrong hands. The remaining Arguses have found a new role as display models at Air Bases and Canadian museums.
Equal to the ageing Lancasters the RCAF was looking for replacements for it's C-54GM North Star. The new planes where primarily intended to provide personnel and logistics support for Canadian Forces in Europe. Since Canadair had already acquired a licence for the Bristol Britannia, Ottawa announced in January 1957 plans for a fleet of long range transports based on the Britannia. Canadair received a contract for 8 aircraft, later increased to 12. Canadair designation CL-44-6 and CC-106 by the RCAF.The design used the modified Argus wings and controls. The fuselage was almost identical to the Britannia 300 with two Cargo doors on the left-hand side. The cabin was pressurised to maintain a cabin altitude of 2.400m at 9.000m (30.000 ft). The Yukon could accommodate 134 passengers and a crew of nine. In the casualty evacuation role it could take 80 patients and a crew of 11. The RCAF had specified the CL-44 to be equipped with Bristol Orion engines. When the British ministry of Supply dropped the Bristol Orion the RCAF decided to use the Rolls Royce Tyne 11. The roll out of the Yukon was a disaster all over. When the prototype was supposed to be pushed out of the hangar the tail was too high. The first plane took off 15 November 1959. During test flights all kind of problems where encountered from complete electrical failure to engines shaking loose and almost falling off. Rolls Royce had problems delivering engines resulting in "Yukon gliders" being parked outside Canadair as late as 1961.
Once in Service the Yukon proved very well and on December 1961 a Yukon set a world record for its class when it flew 10.860 Km (6.750mi) from Tokyo to Trenton, Ontario, in 17 hours three minutes at an average speed of 640 Km/h (400 mph). Later a Yukon even set a new record staying airborne for 23 hours and 51 minutes. These records stayed untouched until broken by the new 747SP in 1975. Eleven Yukons flew for 437 Transport Squadron. Two flew as VIP transports for 412 Squadron.
The Yukons retired in March 1971 and were replaced by Boeing 707. The Yukons might have served longer with the RCAF but for two factors. The RCAF needed an aircraft, which could operate as an in-flight refuelling tanker, and second the chronic shortage of spares. The latter problems resulted from the fact that the CL-44 had never gone into large-scale production. Consequently spare parts tended to be in short supply and relatively expensive. The Yukon flew 65 million miles, 1.5 billion passenger miles and 360 million ton-miles. All Yukons were sold to South American and African operators since it could not be registered in Northern America or Europe since the Britannia windshields did not meet new security standards.
The SWINGTAIL Variant
At a similar time as the Yukon
contract came in Canadair announced its intentions to re-enter the civilian market after
the DC-4M2, C-4 North Star. The civilian CL-44 was supposed to be a slightly modified
Yukon. Higher rated engines and only one cargo-door. The APU that the Yukon carried in the
nose was removed to increase payload. The plane generated little interest with the
passenger airlines, which had their sight on the new Jets. Cargo airlines found the cost
projections made by Canadair compared with the high operating cost of Super constellations
and DC-6B very interesting. The Jets were not an option at that time because of the high
purchase cost. The Flying Tiger Line and Seaboard World Airlines pushed Canadair to
develop a system to load and unload the 29.5 tons of cargo in 45 minutes enabling
turn-around in less then 60 minutes. Canadair looked at the Navy who could fold the wings
of their aircraft so they asked themselves why not folding the tail of the aircraft. This
had been done before in England around 1920 but on planes with a payload less then one
ton. This became the famous "Swingtail" even adopted on some DC-4 and DC-6.
Canadair also designed a loading tool to load the CL-44. This loading tool is today known
as the "High-loader ". The design is today used all over the world to load cargo
planes. After the initial eight Yukons, Canadair built the first
civilian CL-44 with a swingtail. This plane was designated CL-44D4. Canadair built the
plane without a launch customer. This Aircraft, serial #9, was used as a demonstrator for
many years. It was built in 1960 but not sold to Loftleidir until 1965. While the
prototype was being built a major problem arose since the FAA refused to certify the
Britannia type windshields for its vision standards. Help came from General Dynamics from
their CV880/990. The windshields were compatible enough to be adopted into the flight deck
structure. After the Comet disaster a requirement was set for structural fatigue testing.
A large watertank was set up and the CL-44 had to simulate 80.000 flight hours to be
certified for 40.000 hours.The Flying Tiger Line ordered 12 aircraft and Seaboard
World Airlines ordered 7 aircraft. Many other Airlines showed interest in the D4. Pakistan
ordered five aircraft, but the Canadian government refused to issue an export permit for
Pakistan for fear of offending India. Saudi Arabia withdrew their two aircraft after
Pakistan was out of the game. Japan Cargo Airlines ordered three Aircraft but cancelled
after Japan airlines opposed the purchase. BOAC appeared to be a certain client until
their management changed and stopped the discussion. (BOAC Cargo later leased a D4 from
Seaboard while waiting for their new Boeing 707).In 1960 the USAF Military Air Transport Service (MATS) was
thinking of buying up to 232 D4s. The United States wanted Canada to bolster its
northern fighter defences and proposed a deal whereby the Canadian would buy 100 F-101
Voodoo fighters plus a possible participation in the maintenance of the Pinetree early
warning radar line. The quantity of D4s had dwindled to 37 when Ontario
conservatives objected on the grounds that it would be politically unacceptable to award a
major aircraft contract to Quebec after having cancelled the Ontario-built Avro Arrow.
MATS quickly changed their minds and bought Boeing C-135.Canadair built a total of 39 CL-44 aircraft. 12 CC-106
Yukon's and 27 CL-44D4 models. Seaboard World Airlines bought seven aircraft and The Flying Tiger
Line bought twelve. Later Slick Airways ordered four more. This left Canadair with the
unsold prototype and three CL-44D4s already finished but not sold. Canadair knew that the
Icelandic low fare carrier Loftleidir was searching for alternatives to replace their
ageing fleet of DC6B. Loftleidir bought those with the condition that they would all be
stretched to accommodate more passengers. An engineering office in the United States on
behalf of Loftleidir carried out a study to stretch the CL-44. Canadair carried out the
work and the first stretched D4 flew on November 8, 1965. Loftleidir had already taken the
other three D4s into service but returned them one after another in order to be converted.
An other D4 was converted by Jack Conroy Aviation of California into a CL-44-0
"Guppy". This aircraft had its upper fuselage removed and replaced by an
enlarged section, which raised the cabin height by 1.5m.The forty-four proved to be a nightmare for mechanics. But
it was an extremely profitable aircraft to run. At the time the fuel burn of a CL-44 was
half compared to a Boeing 707.
Source: Canadair: The First 50 Years by Ron Pickler