04/30/2010. Remarks by Johan Visschedijk: "As a result of the successful trials of the Viking and its operation by the Royal Air Force in Transport Command, a new version was evolved, specially adapted to military requirements as contained in specification C.9/46.

One requirement was for an aircraft capable of rapid conversion to fulfill a number of different roles; troop carrier, military freighter, ambulance, glider-tug, paratroop transport and for supply dropping. These duties led to the Valetta C. Mk 1 acquiring the description of 'five aircraft in one' Thus, the concept of all-round air transport utility, born many years before in the Middle East and India with Vernons, Victorias and Valentias, at last received official recognition. Later on, the multi-role military aircraft was greatly developed in the VC10s for RAF Transport Command.

New features embodied in the Valetta were a stronger cabin floor permitting a contact wheel-loading of 1,500 lb (680 kg) anywhere on the structure and the cutting of a large aperture in the side of the fuselage between the wings and the tail for loading and off-loading bulky military equipment. The double door in this structurally reinforced aperture had a smaller door inserted in it for personnel access and for use as a paratroop exit. Lashing points were provided in the fuselage floor and on the side walls for anchoring cargo.

Various types of seats, according to role, oxygen cylinders, vehicle ramps, a loading winch, roller runways on the floor and over the spar box in the cabin, glider-towing attachments, stretchers and sound-proof side walls (in the ambulance version), comprised the quickly removable aircraft equipment.

As a troop transport, the Valetta could carry 34 soldiers with full equipment; as an ambulance, it had provision for 20 stretcher cases with two medical orderlies; as a paratrooper, 20 troops with nine 350 lb (159 kg) containers of fighting equipment and supplies carried externally on twin racks under the center fuselage could be accommodated; and for glider-towing, a heavy pyramid structure was attached within the rear fuselage, for connection of the hook and release gear.

In the prototype and the VIP C.Mk.2, the extreme tail of the fuselage carried a neatly faired cone, but normally the Valetta had a blunt rear end. With these military features, the Valetta's all-up weight was 36,500 lb (16,556 kg).

Hercules 230 engines were installed to cater for this increase of some 2,000 lb (907 kg) over the all-up weight of the Viking 1B, each providing 2,000 hp for take off. Other design changes included flexible-bag fuel tanks, and stronger oleo landing gear legs with longer stroke to cope with the rougher conditions of military operational landings. The prototype Valetta, VL249, first flew on 30 June, 1947, at Brooklands in the hands of Captain J. 'Mutt' Summers.

A flying navigational classroom variant, to specification T.1/49, was produced, with 10 student training positions built into the cabin; the external distinguishing feature of these T.Mk.3s was the row of plastic astrodomes along the top of the fuselage; they were used by the Air Navigation Schools and by the RAF College, Cranwell. Eighteen T.Mk.3s were converted to the T.Mk.4 variant for radar training and were distinguished by their longer nose, which accommodated the radar scanner and comprehensive equipment.

Experimental work undertaken by Vickers with the Valetta included landing gear research, with four-wheel and eight-wheel bogies, to explore their characteristics for soft landings. VL275, the ninth Type 645 production aircraft, was used in taxiing, take off and landing tests at Wisley, at Hurn where the concrete runway was used, and at Christchurch airfields. Little ground-handling difference was observed between the bogie and standard type landing gears.

Of the Valetta, 263 aircraft were produced:

Type 607 Valetta, prototype, s/n VL249 (1)

Type 637 Valetta C.Mk.1, s/n VL262-VL266 (5)

Type 645 Valetta C.Mk.1, s/n VL267-VL282 (16)

Type 651 Valetta C.Mk.1, s/n VW140-VW165, VW180-VW206, VW802-VW851, VW855-VW864, VX483-VX485, VX490-VX499, VX506-VX515, VX521-VX530, VX537-VX546 and VX555-VX563, WD157-WD171, WJ491-WJ499 (190)

Type 659 Valetta C.Mk.2, s/n VX571-VX580, WJ504 (11)

Type 664 Valetta T.Mk.3, s/n VX564, WG256-WG267, WJ461-WJ487 (40)

The pictured aircraft was the first of a batch of ten aircraft (s/n WJ491-WJ499, and WJ504) ordered as C.Mk.1s under the ninth and last Valetta contract, 6/AIR/5929/C.B.6(b). WJ491 was delivered to RAF Defford on May 3, 1951; it served with A&AEE at Boscombe Down before it became the last Valetta to be withdrawn from use on April 10, 1972, it subsequently perished at the Gatow (Berlin, Germany) fire dump.

The last production aircraft, Type 659 C.Mk.2, s/n WJ504, was finished as a VIP transport with up to 15 seats for high-ranking personnel, and carried 116 lb (53 kg) extra fuel. It was delivered to No. 30 Squadron at Abingdon on July 9, 1951."