Sunday, October 30, 2011

British United Airways Carvair

The Carvair was a project of Freddie Laker's Aviation Traders Ltd to convert surplus DC-4/C-54s to carry cars as a successor to the aging and increasingly inadequate Bristol 170 Freighter/Superfreighter, the mainstay of the car ferry airlines since the late-1940s. A total of 21 were produced.

The Bristol Freighter/Superfreighter's main drawback was its limited payload and even the "long-nosed" Superfreighter was only able to accommodate three cars (in addition to 20 passengers). This made carrying cars by air a risky business; a booked car failing to turn up made the flight unprofitable as a result of the one-third cut in payload. Also the average length of British cars increased during the 1950s: the average UK car in 1959 was 10 inches (25 cm) longer than in 1950.

When the major airlines replaced their piston airliners with new Boeing 707 and Douglas DC-8 jets on their prestige long-haul routes, the price of a second-hand DC-4 dropped to as little as £50,000. The conversion of each of these airframes into car-passenger carriers cost about £80,000. This was easily affordable by smaller airlines. Freddie Laker's cardboard model of a converted DC-4 featuring a door in the nose and a flight deck raised "above" the fuselage had shown that its payload was superior to the Bristol Freighter/Superfreighter. The aircraft was designed to accommodate five average-sized British cars plus 25 passengers as a result of the DC-4's longer and wider fuselage. British Air Ferries (BAF) operated its Carvairs in a flexible configuration, either accommodating five cars and 22 passengers or 2-3 cars and 55 passengers, permitting it to change over from one configuration to the other in about 40 minutes.

In addition, the DC-4's lack of pressurisation made it ideal for low-altitude cross-Channel flights that did not go high enough to require a pressurised cabin. This made the proposed structural conversion straightforward. The new aircraft was christened Carvair from "car-via-air".

Initially it was thought that second-hand, pressurised DC-6 and DC-7 airframes could be converted into larger, "second generation" Carvairs within 15 years of the original DC-4-based Carvair's entry into service.

The actual conversion of the original aircraft entailed replacing the nose cone with one 8 ft 8 inches (2.64 metres) longer, the flightdeck being raised to allow a sideways hinged nose door. It also entailed more powerful wheel brakes and an enlarged tail, often thought to be a Douglas DC-7 unit, but actually a completely new design. The engines were four Pratt & Whitney R-2000 Twin Wasp radial engines.

The prototype conversion first flew on 21 June 1961. Of the 21 Carvairs produced, numbers 1, 11 and 21 were done at Southend Airport and the balance at Stansted Airport. The final three were delivered to Ansett Australia, which supplied its own DC-4s to ATL for conversion, unlike the previous 18 aircraft that were purchased by ATL and either sold on or transferred to associate company British United Air Ferries (BUAF). The first flight of the last conversion, number 21, for Ansett, was on 12 July 1968.

 Eight were written off in crashes and only one is still flying.

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