The Convair CV-240 is an American airliner produced by Convair from 1947 to 1954, initially as a possible replacement of the ubiquitous Douglas DC-3. Featuring a more modern design with cabin pressurization, the 240 series was able to make some inroads as a commercial airliner and also had a long development cycle which resulted in various civil and military variants. Although reduced in numbers through attrition, the "Convairliners" in various forms continue to fly into the 21st century.
The design began its life in 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 and 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 had changed its requirements to require pressurization and deemed the design too small. The first prototype was used by Convair for development work for the 240 series before being 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 that 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 like the Vickers Viscount, Convair produced the Model 440 Metropolitan, with more streamlined cowlings, new engine exhausts, and better soundproofing for the cabin. As the "Super 240" evolved into the CV-340 and CV-440, the limit of piston-engine performance was reached, and future development centered on conversion to turboprop power.
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, the production of the 240 series was temporarily halted. 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 proved popular in South America. The CV-340 earned an enviable 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.
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.
Convair CV-240
Initial production version. Powered by two Pratt & Whitney R-2800 engines.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 and the prototype being converted back to piston power.
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. In 1977, a CV-300 was involved in an accident that killed three members and the manager of the rock group Lynyrd Skynyrd.
Convair 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.
Convair CV-440 Metropolitan
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 1953 until 1980 without a single accident.
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. 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.
Convair CV-580
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) 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.
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.
Convair CV-640
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
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 (29,18 m) 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. 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 was operated by Air Freight NZ.
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
American Inter-Island - CV-440 (wholly owned subsidiary of American Airlines which operated flights between San Juan, St. Thomas and St. Croix in the Caribbean)
Mackey Airlines (also known as Mackey International) - CV 440 & CV 580
Metro Airlines (via its wholly owned Metroflight division) - CV-580 (former Frontier Airlines aircraft that were operated for American Eagle via agreement with American Airlines)
Sun Valley Key Airlines - CV-440 (U.S. commuter air carrier previously known as Sun Valley Airlines that operated out of Salt Lake City, UT and Sun Valley, ID which then changed its name back to Key Airlines)
Trans-Texas Airways (TTa) - CV-240 & CV-600
Texas International Airlines - CV-600 (former Trans-Texas Airways aircraft)
Time Air - CV-580 & CV-640 (former Norcan Air and North Caribou, also one previously owned by Domino's Pizza)
United Airlines - CV-340 & CV-580 (CV-580 aircraft operated via wet lease contract by Frontier Airlines (1950-1986) as the replacement for former United Douglas DC-6 service to Elko, NV and Ely, NV)
National Research Council (Canada) (CV-580 C-FNRC)
Canada Centre for Remote Sensing, later Environment Canada, retired to the Canada Aviation and Space Museum in June 2015 in recognition of its historical significance to Canadian science (CV-580 C-GRSC)
Specifications (CV-240)
Data from General Dynamics Aircraft and their Predecessors
