The Convair CV-240 is an American airliner that Convair manufactured from 1947 to 1954, initially as a possible replacement for the ubiquitous Douglas DC-3. Featuring a more modern design with cabin pressurization, the low-wing, primarily piston-driven 240 series made some inroads as a commercial airliner, spawning nearly a dozen civil variants, and five for the military, including turboprop versions for both. Though reduced in numbers by attrition, various forms of the "Convairliners" continue to fly in the 21st century.
The design began with a requirement by American Airlines for an airliner to replace its Douglas DC-3s. Convair's original design, the unpressurised Model 110, was a twin-engine, low-wing monoplane of all-metal construction, with 30 seats. It was powered by Pratt & Whitney R-2800 Double Wasp radial engines. It had a tricycle landing gear, and a ventral airstair for passenger boarding. The prototype Model 110, registration NX90653, first flew on July 8, 1946. By this time, American Airlines had changed the requirements to include pressurization and deemed the design too small. Convair used the first prototype for 240 series development work before it had the plane broken up in 1947.
To meet the requirements of airlines for a pressurized airliner, Convair produced a revised design—the Model 240. This had a longer but thinner fuselage than the Model 110, accommodating 40 passengers in the first pressurized, twin-engined airliner. The 240 first flew on March 16, 1947.
The Model 240 was followed by the Model 340, which had a longer fuselage, longer-span wings, and more powerful engines. The 340 first flew on October 5, 1951. In 1954, in an attempt to compete with turboprop-powered airliners such as the Vickers Viscount, Convair produced the Model 440 Metropolitan, with more streamlined cowlings, new engine exhausts, and better cabin soundproofing. As the "Super 240" evolved into the CV-340 and CV-440, the design reached the limit of piston-engine performance, and future development centered on conversion to turboprop power.
Convair delivered the first production Convairliner to American on February 29, 1948. They delivered a total of 75 to American—and another 50 to Western Airlines, Continental Airlines, Pan American Airways, Lufthansa, KLM, Swissair, Sabena, and Trans Australia Airlines. A CV-240 was the first private aircraft used in a United States presidential campaign. In 1960, John F. Kennedy used a CV-240 named Caroline (after his daughter) during his campaign. This aircraft is now preserved in the National Air and Space Museum.
After aborted negotiations with TWA and Eastern for "Super 240" orders, Convair temporarily halted 240 series production. In response to a United inquiry, Convair redesigned the Super 240, calling it the CV-340. United ordered 55, and more US orders came from Braniff, Continental, Delta, Northeast, and National. Other orders came from abroad, and the CV-340 was popular in South America. The CV-340 earned a reputation for reliability and profitability, and was developed into the CV-440 Metropolitan, the final piston-engined variant of the Convairliners. Kelowna Flightcraft Air Charter, the major remaining operator of this model, currently holds the type certificate for this aircraft. Used price for a Convair 240 in 1960 was around £40,000.
Data from: General Dynamics Aircraft and their predecessors
Unpressurized prototype with seats for 30 passengers. 89 ft (27.13 m) wingspan, 71 ft (21.64 m) length, powered by two 2,100 hp (1,567 kW) Pratt & Whitney R-2800-SC13G engines. One built.
Initial production version, with seats for 40 passengers in a pressurised fuselage. Powered by two Pratt & Whitney 2,400 hp (1,800 kW) R-2800 engines. 176 built (excluding military derivatives).
Turboprop-powered conversion fitted with Allison T38 engines. It became the first turboprop airliner to fly in the United States (on December 29, 1950), but problems with the engines resulted in development being terminated. Used as a test bed before being converted back to piston power.
A conversion from a Convair CV-240 with two R-2800 CB-17 engines and nacelles as used on the CV-340.
Built for United Airlines and other operators including KLM, the CV-340 was a CV-240 lengthened to hold an additional four seats. The wingspan was extended for better performance at higher altitudes. The CV-340 replaced the DC-3 in United service. The airline flew 52 340s for 16 years without a fatality. KLM operated the type from early 1953 until mid-1963. Many CV-340 aircraft were converted to CV-440 standard.
CV-340 with improved soundproofing and an option for weather radar. Maximum weight rose to 49,700 lbs. An optional increase from 44 to 52 passengers was facilitated by the replacement of the carry-on luggage area with two more rows of seats, marked by the addition of an extra cabin window. This option was taken up by several airlines including Swissair, Lufthansa and SAS. Finnair operated the type from 1956 until 1980.
On March 13, 1957, Brooklyn Dodgers owner Walter O'Malley purchased a Convair 440 Metropolitan for $734,908.96 to travel the team during the 1957 season, and this plane was used as the team moved to Los Angeles for the 1958 season.
Conversion from a Convair CV-340 aircraft with two Napier Eland turboprop engines in place of the piston engines. Six aircraft were converted by Napier for Allegheny Airlines. Cost for the conversions was £160,000 per-aircraft. 12 built as new-builds by Canadair for RCAF as CC-109 in 1960 for £436,000 per-aircraft. First flight February 9, 1955. When Rolls-Royce purchased Napier, the Eland program was terminated, and the Allegheny aircraft were converted back to piston power, but were later converted to Convair 580s with Allison turbo props.
Conversion from Convair CV-340 (Allison Prop-Jet Convair 340) or CV-440 aircraft with two Allison 501 D13D/H turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers, an enlarged vertical fin and modified horizontal stabilizers. The conversions were performed by Pacific Airmotive on behalf of the Allison Engine Company. Cost of the conversions was around £175,000 per aircraft and took 60 days. The CV-580 served with the original Frontier Airlines (1950-1986), Allegheny Airlines, and North Central Airlines for many years and was also the first aircraft type operated by American Eagle on behalf of American Airlines in code sharing feeder service. General Motors Air Transport (GMATs) also used CV-580's on their internal air shuttle operation which ran between Detroit Metro Airport, Dayton, OH, Anderson, IN and other locations as needed.
Firefighting airtanker conversions with retardant tanks and dropping systems.
Conversion from a Convair 240 aircraft with Rolls-Royce Dart turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers. CV-600 conversions were performed by Convair. The CV-600 first flew with Central Airlines on 30 November 1965 and also served with Trans-Texas Airways (TTa) and successor Texas International Airlines for many years. The CV-600 aircraft that flew with Air Metro Airways was configured as a 40-passenger airliner. In 2012 the last Convair CV-600 (Rhoades Aviation) went out of service.