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.

Design and development 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.Gradidge 1997, p. 10.

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.Wegg 1990, pp. 187–188. The 240 first flew on March 16, 1947.Wegg 1990, p. 188.

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.Wegg 1990, pp. 188–189. 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.Wegg 1990, p. 192. 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.

Operational history

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.Gradidge 1997, pp. 10–11. 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.Flight November 18, 1960, p. 794.

Variants Data from: General Dynamics Aircraft and their predecessors

Civil variants

Convair Model 110 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.Wegg 1990, p. 183. Convair CV-240 Initial production version, with seats for 40 passengers in a pressurised fuselage. Powered by two Pratt & Whitney R-2800 engines.Wegg 1990, pp. 188, 199. 176 built (excluding military derivatives).Wegg 1990, p. 189. Convair CV-240-21 Turboliner 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.Wegg 1990, p. 194. Convair CV-300 A conversion from a Convair CV-240 with two R-2800 CB-17 engines and nacelles as used on the CV-340."Convair-Liner History." The American Museum of Aviation. Retrieved: October 21, 2011.

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.Gradidge 1997, p. 13

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. Convair CV-540 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.Frawley 1997, p. 86. 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.Flight November 18, 1960, p. 793. 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. Convair CV-580 Airtanker Firefighting airtanker conversions with retardant tanks and dropping systems. Convair CV-600 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.Flight International, October 3–9, 2006.

Conversion from a Convair CV-340 or -440 with Rolls-Royce Dart turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers. The conversions were performed by Convair. In 2012, a total of seven Convair CV-640 aircraft remained in airline service, with Rhoades Aviation (one) and C&M Airways (six). Convair CV-5800

A stretched Convair CV-5800 of IFL Group with this aircraft being developed by Kelowna Flightcraft (now KF Aerospace) in Canada. Conversion from former US Navy C-131F Samaritans by Kelowna Flightcraft Ltd. (KF Aerospace since 2015) in Canada. The CV-5800 is a C-131F Samaritan stretched by 16 ft 7 in (4,98 m)aerofavourites, Convair CV-240 - CV-640 . Retrieved: August 17, 2016. with the Samaritan's original tail unit rather than the enlarged tail of the CV-580. These conversions also have a new freight door, digital avionics with EFIS and Allison 501-D22G engines in place of the original R-2800 engines. The prototype of this conversion first flew on February 11, 1992; the type certificate was issued on December 11, 1993.Gradidge 1997, p. 39. A total of six aircraft were converted (construction numbers 276 to 279, 309, 343) and mostly used by Contract Air Cargo (later IFL Group); one aircraft later operated by Air Freight NZ was then returned to KF Aerospace for operation in their own fleet.Klee, Ulrich & Bucher, Frank et al. jp airline-fleets international 2013/14. Sutton, UK, 2013, pp. 321 and 583.Ruud Leeuw, ConvairLiners background information. Retrieved: August 17, 2016. Allison Turbine ATF 580S Turbo Flagship Stretched Convairliner conversion.

Military variants Convair C-131 Samaritan The CV-240/340/440 series was used by the United States Air Force for medical evacuation and VIP under this designation Convair T-29 trainer A trainer model of the C-131 was used to instruct navigators and radio operators Convair R4Y Samaritan The United States Navy used the Samaritan under this designation Canadair CC-109 Cosmopolitan Conversion from CV-440, with Napier Eland turboprops in place of the piston engines. The conversions were performed in Canada by Canadair. In Royal Canadian Air Force and later in Canadian Armed Forces service they were known as the CC-109 Cosmopolitan. All were re-engined in 1966 with Allison 501-D13 engines. Canadair CL-66 Company designation for the CC-109 Eland powered variant

Operators

Civil operators

Africa

Air Algerie – CV-640 Ethiopian Air Lines – CV-240Archive 1992 No. 3, pp. 64–65 Kardair (Libya) – CV-440 Titan Helicopter Group (South Africa) – 3 CV-580 Regional Air (South Africa – 2 CV-580) Rovos Air (South Africa – CV-340)

Asia

Air Jordan – CV-240Flight April 8, 1960, p. 491. Air Maldives – CV-440 All Nippon Airways – CV-440 Ariana Afghan Airlines – CV-340Wragg 1969, p. 7. (CATC), - 6 CV-240Best Air-Britain Archive Summer 2009, p. 83Best Air-Britain Archive Autumn 2009, p. 104 Garuda Indonesia – CV-240,Bridgman 1955, p. 21 CV-340 & CV-440Veronico & Larkins 2005, p. 58 Iran Air – CV-240 Japan Domestic Airlines – CV-240 Orient Airways CV-240Veronico & Larkins 2005, pp. 59–60 Pakistan International Airlines – CV-240 Philippine Airlines – CV-340Bridgman 1955, p. 26 Royal Air Cambodge – CV-440 Saudia – CV-340Bridgman 1955, p. 27 Seulawah Air Services – CV-640 South East Asia Air Transport – CV-340 Toa Airways

Oceania

Air Chathams – CV-580 Air Fiji – CV-580 Air Freight NZ – CV-580 & CV-5800 Airlines of New South Wales – CV-440 Airlines of South Australia – CV-440 Ansett Airlines – CV-340,Bridgman 1955, p. 14 CV-440 (some were formerly operated by Braniff International Airways)Veronico & Larkins 2005, pp. 57–558 Chathams Pacific – CV-580 Pionair – CV-580 Real Tonga – CV-580 Trans Australia Airlines – CV-240Bridgman 1955, p. 15

Europe

Aviaco – CV-440Flight April 8, 1960, p. 493. Alitalia – Linee Aeree Italiane – , CV-340 & CV-440Flight April 8, 1960, p. 492. Condor (& predecessor Deutsche Flugdienst) – & CV-440 Delta Air Transport – CV-440