The Douglas DC-3 had proven itself in commercial service before the Second World War. Commercial operators looked ahead, into peacetime and planned a successor.
Convair (born in 1943 by a merger between Consolidated Aircraft Corporation and Vultee Aircraft Inc. as Consolidated Vultee Aircraft Corporation, which was changed into Convair in 1947) received from American Airlines the specifications for a twin-engined short-range airliner: suitable for routes up to 1.000 miles. Thus led to model 110, now all but forgotten. Only one was built and by the time of its first flight (July 08th, 1946) the CV240 was on its way. But it was the forerunner to a series of successful airliners, now remembered as the ConvairLiners. When boarding a flight in the 1950s one would likely board a Convair product.
American Airlines ordered 75 Convair Model 240 airliners which provided seating for 40 passengers. No prototype was built and the first flight took off on March 16th, 1947. American Airlines accepted its first aircraft in June 1948. The improvement over the 110 was that it was larger and the cabin featured pressurisation. Western Airlines bought 10 and Pan American followed with an order for 20. Overseas an order was booked for KLM, for an order of 12 CV240s. Other customers were Trans Australian (5), Aerolinas Argentinas (5), Swissair (4). Sabena (6) and Central Air Transport (China, 6).
Times were lean and competition was tough as there were still a large number of DC-3s around. But 176 CV240s were produced and the USAF ordered 390 as C-131 (C-131AB, YC-131C, C-131D) transport and T-29 (T-29A/B/C/D) trainer. Over the years they were modified and numerous redesignations were issued (EC-131B, JC-131B, NC-131B, JYC-131C, VC-131D, NC-131H, VC-131H and even more for the T-29). But for these military orders Convair was in financial difficulties as the CV240 was underpriced to compete with the Martin 202. They had to go forward and produce an improved model.
The CV340 model first flew on October 5, 1951. The fuselage was stretched by 16 inches forward of the wing and 38 inches aft. The Pratt and Whitney R-2800 engines were uprated. Also the wing on this model was larger to improve performance on high altitude airfields. Customers were (a.o.): United Air Lines (55), Braniff (20), Continental (7), Hawaiian (5), Delta (20), Pan American (6), KLM (14) and Garuda Indonesian (8). Some 209 civil variants were produced and 102 for the USAF and US Navy, between 1952 and 1956.
By 1954 it was clear that Convair faced tough competition from the Vickers Viscount, which gave a smoother, quieter flight thanks to its Roll Royce Dart turboprops.
Some 8 years after the first flight of a CV240, it was another Convair product with improved performance that took to the sky: the CV440 "Metropolitan" on October 6, 1955. A radar was introduced, which lengthened the nose by 2ft 4ins. The CV440 carried 52 passengers in a high density layout. It also featured redesigned engine nacelles and other improvements like sound-proofing blankets in the cabin and sound-damping tape where vibration was worst. Improvements as they were, they did not equal the Vickers Viscount. Continental was the first customer and production ran till 1958 with 199 CV440s produced.
Convair produced kits to have the early CV340s be improved to the level of the CV440.
More than 230 of the three early models were eventually converted to turboprop power in three programmes between 1955 and 1967.
Improvements largely concentrated on the engines: the airliners wanted to go higher ("over the weather" avoiding the turbulence due to the restricted performance ceiling), faster and further... This of course has never changed in commercial aviation.
The CV240, CV340 and CV440 were for almost all customers fitted with Pratt & Whitney R-2800 "Double Wasp" engines.
Allison 501-A4 engines were tested on a CV240 on December 29, 1950. This development led to the use of Allison 501D engines for the Lockheed Hercules and Lockheed Electra. But the attempt by the British Napier company in 1955 was more successful, when it flew a Napier 3.000hp engined CV340. Six were converted for Allegheny and received the designation CV540 "Cosmopolitan".
As Convair was preoccupied with the development of the Convair CV880 jet, they transferred the tooling to Canadair LTD., the Canadian General Dynamics subsidiFary (both Canadair and Convair were owned by the Electric Boat Company), so that new aircraft could be offered. Three unsold CV440s were converted by Canadair to CV540 standard as CL-66C (1 demonstrator and 2 for Quebecair). Canadair had planned to build passenger CV540s as CL-66As, but no civil orders came in. But 10 CL-66B "Cosmopolitans" were produced for the Royal Canadian Air Force (deliveries in 1960 and 1961). These had cargo-doors and were of the same standard as the USAFE C-131E (CV440-72). The 3 CL-66Cs were transferred to the RCAF, too, in 1962. This ended the Eland-powered conversions, as meanwhile Roll-Royce had taken over Napier Engines in 1962 and production of the Eland-engines for conversion was stopped. The RCAF CL-66s were converted, after 1966, to CV580 standard.
In fact Convair was too busy with designing its 880 (jet) model and so PacAero Engineering stepped in to design a turboprop. So the next conversion saw use of the Allison 501-D13 turboprop and was designated CV580 (although at that time also referred to as "Allison Prop-Jet Convair 340/440", later dubbed the Super Convair: undoubtedly a better sales pitch!). Its first flight was on January 19th, 1960 and CoA was issued on April 21st that year.
Orders were slow (facing competition of the Electra and the Vickers Viscount), but it did have an appeal to executive operators (e.g. General Motors, Ford Motor Company, the FAA).
Allegheny (44), North Central (35) and Frontier became major users of the CV580. A total of 130 aircraft were converted.
Then there was the "Super 580". The Super 580 Aircraft company, a division of Flight Trails Inc., took CV580 airframes and fitted it with Allison 501-D22G turboprops. These were able to produce 4.000 horsepower and were fitted with four-bladed Hamilton Standard 54H60-77 propellors. It claimed to give a 2.5% improvement in fuel consumption, improved performance, reduced operating costs and various other goodies. It was first flown on March 21st 1984. It did not catch on.
Gordon Hamilton wrote me in April 2006: |
Enjoyed your site. Ego compells me to point out that Hamilton Aviation performed the first retrofit of 501-D22G engines of the CV580 for our prototype customer, The Way International.
Flight Trails just bought the program afterwards.
After the problems on the Convair CV880 and CV990 jetliners were solved, Convair regained interest in the Convairliners. The CV580 was selling slow and the Allison engines were too powerful to be fitted to the CV240s. A choice was made for the Rolls Royce Dart 542-4 with 4-bladed Dowty props. An APU could be fitted in the right-hand nacelle, behind the firewall. Power could be boosted with an injection of water methanol mixture. Such conversions from CV240s were redesignated CV600s and for the CV340 & CV440 models the designation CV640 was found. Both these modifications were first flown in 1965. Central Airlines was a customer for the CV600 while Trans Texas bought the kits and rebuilt 25 CV240s to CV600s.
A total of 39 CV600s were converted and 27 were converted to CV640. The CV640 had the disadvantage of having a heavier airframe with the same powerplant, resulting in less performance. Conversions to the CV640 were also carried out abroad: by Aviolanda in Holland (2 for Martin's Air Charter, 1 for SATA and 4 for Air Algerie) and Scottish Aviation at Prestwick (6 for Pacific Western at Vancouver).
One would have thought that that would be the end of the line. NOT !
On February 11th, 1992 (after some 2 years delay) Kelowna Flightcraft of Kelowna, British Columbia (Canada) saw the first flight of its stretched version the CV5800. Follow this link for a photo and specifications CV5800. By 2001 3 were produced for Contract Air Cargo, with one conversion for the same customer in progress (CV340 N5248N msn279).
|CONTRACT AIR CARGO = TSU (Division of IFL Group Inc. / Sister company of Corporate Express), Pontiac-Oakland,MI|
|Founded: 1992||Head: Alan C. Ross||ICAO Callsign: TRANS-AUTO|
|REGISTRATION||TYPE OF AIRCRAFT||Construction nbr. (msn)||REMARKS|
|N14094||CV5800||277||cvtd Convair 340-71 / C-131F|
|N5248N||CV5800||279||cvtd Convair 340-71 / C-131F|
|N131FL||Convair 580 (F) (SCD)||155||cvtd 340-42/440|
|N141FL||Convair 580 (F) (SCD)||111||cvtd 340-32|
|N151FL||Convair 580 (F) (SCD)||51||cvtd 340-38|
|N161FL||Convair 580 (F) (SCD)||430||cvtd 440-95|
|N171FL||Convair 580 (F) (SCD)||318||cvtd 440-35|
|N181FL||Convair 580 (F) (SCD)||387||cvtd 440-24|
|N191FL||Convair 580 (F) (SCD)||326||cvtd 440-79/C-131D|
|N723ES||Convair 580 (F) (SCD)||217||cvtd 340-67/VC-131D|
|N991FL||Convair 580||508||cvtd 440-0|
|N371FL||Convair 5800 (F) (SCD)||309||cvtd 340-71 (C-131F)|
|N381FL||Convair 5800 (F)(SCD)||276||cvtd 340-71 (C-131F)|
|N391FL||Convair 5800 (F)(SCD)||278||cvtd 340-71 (C-131F)|
Source: JP Airline Fleets 2001/02.
|Significant dates in Convair-Liner history:
(from Convair Twins [Airliner Tech Series, Vol.12] by Nicolas A.Veronico, 2005)
Sep.1945- War ends. Consolidated Vultee announces that it will build the Model 110, a low-wing, twin-engine, tricycle-gear, 30-passenger, medium-range airliner.
08Jul1946- The sole Model 110, NX90653, flies on this date with Russell R.Rogers and Art Bussy at the controls.
26Dec46- American Airlines agrees to buy 100 CV-240s at a cost of usd 18 million, the largest commercial aircraft order to date.
16Mar47- First flight of the CV-240 Convair-liner prototype (N90849, msn 1) at San Diego is flown by company pilots Sam Shannon and Russell Rogers.
26Oct50- The last Convair 240 built, msn 178, is delivered to Garuda Indonesian Airways. The plane is registered PK-GCI and named Sikatan. A total of 178 Convair-Liner 240s were built.
05Oct51- Convair 340, N3401 msn 1, makes its first flight from San Diego with company test pilot Sam Shannon in the left seat.
28Mar52- The first airline delivery of a ConvairLiner 340 is made to United Air Lines (340-31, msn 3, N73103). ("Randy Moore wrote me in May 2009: 'serial number 3 – N73103 – was the second aircraft delivered in 1952. I’m looking out the window at the first – N73102 originally, now N580AS owned and flown on a daily basis by Honeywell.') N580AS has c/n 2; 'The Convairliners Story' by J.M.Gradidge (Air-Britain 1997) lists c/n 2 N73102 was manufactured 15Jan52 but only delivered 02Sep52 (United Airlines 'Omaha')
06Oct55- The first flight of the 440 Metropolitan prototype, the modified 340 N8431H msn 202. Continental was the first airline to operate the type, beginning on 08Mar56.
09Feb56- The first Napier Eland-powered Convair 540 (340 conversion, msn 153, G-ANVP) flies from Cranfield Aerodrome, Bletchley, Buckinghamshire, England.
29Feb56- Europe's first Convair 440 Metropolitan (msn 317, OH-LRD) is delivered to Finnair in Helsinki, Finland. The aircraft flies from San Diego to Helsinki, approximately 6.960 miles, in 25 hours, 55 minutes.
20May65- First flight of the Convair 600 (Rolls-Royce Dart powered Convair-Liner 240).
21Mar84- The first Convair Super 580 takes flight. The aircraft is powered by two Allison 501-D22G turbo-props, each rated at 4.000 shp.
11Feb92- Kelowna Flightcraft's stretched Convair 5800 prototype, N5800 msn 276, originally a Convair-Liner 340-71, makes its first flight.