Sunday 18 August 2013

Avro Tudor Four-Engine Airliner



The original Type 688 Tudor was conceived in 1943 to Specification 29/43 as a commercial conversion of the Lancaster for use over the 



North Atlantic as a quick replacement for the bomber-transports then being used

Develpoment
Avro first proposed to build the Avro 687 (Avro XX), which was a Lincoln bomber with a new circular section pressurized fuselage and a 

large single fin and rudder in place of the predecessor's double ones. During the design stage, the idea of a simple conversion was 

abandoned and the Avro 688 was designed, which retained the four Rolls-Royce Merlin engines. It was designed by Roy Chadwick who, 

due to wartime restrictions, could not design a completely new aircraft, but had to use existing parts, tools and jigs. Using the Lincoln's 

wing, Chadwick, who had worked on the Lancaster, designed the Tudor to incorporate a new pressurized fuselage of circular cross-

section, with a useful load of 3,765 lb (1,705 kg) and a range of 3,975 mi (6,400 km).
Two prototypes were ordered in September 1944 and the first, G-AGPF, was assembled by Avro's experimental flight department at 

Manchester's Ringway Airport[1] and first flew on 14 June 1945.[2] It was the first British pressurised civilian aircraft, although the 

prototype initially flew unpressurised. The prototype Tudor I had 1,750 hp (1,305 kW) Rolls-Royce Merlin 102 engines, but the standard 

engines were 1,770 hp (1,320 kW) Merlin 621s.
Tudor was to be a modification of the Lancaster IV (later the Lincoln) with a new pressurised fuselage to carry a load of 1,705kg over 

6,400km. Following the issue of the specification to Avro in March 1944 two prototypes were ordered and production contracts for BOAC 

(14 aircraft, plus six later) followed later in the same year and in 1945.
While development of the original Tudor continued - despite many difficulties - a new version with considerably lengthened fuselage was 

planned. This version was intended for use on the BOAC Empire routes; two prototypes were ordered in 1944, followed by production 

contracts. By this time the first version of the Tudor was available in its production form, but BOAC requirements had altered. This, and 

the aircraft's shorter than planned range, meant that the Tudor was no longer required as a passenger-carrying transport. British South 

American Airways Corporation (BSAAC), however, began using a modified version on their route to South America in 1947, and some of 

the aircraft laid down for BOAC were turned over to this operator. The Tudor 2 (with the lengthened fuselage) suffered a similar fate, and 

these were planned for conversion to freighters for BOAC.


The versions of the Tudor are listed below
Avro 688 Tudor 1. Powered by four Rolls-Royce Merlin 102, 621 or 623 engines. The original short-fuselage Tudor for the Atlantic route, 

seating 12-24 passengers. First flown 14 June 1945;
Avro 689 Tudor 2. Four Rolls-Royce Merlin 102 or 621 engines. The original long-fuselage version for BOAC South African and 

Australian routes. Accommodation for up to 60 passengers. Thirty production aircraft ordered in November 1944 and a further 49 in April 

1945, plus six to be built in Australia. Order reduced to 50 in 1946 and 18 in 1948. Final 18 were to consist of two Mk 2s for development 

work, six Mk 5s for BSAAC - and ten modified to freighters for BOAC.
Avro 688 Tudor 3. Two additional Mk I airframes converted by Armstrong Whitworth for use as VIP transports by ministers.
Avro 688 Tudor 4. Four Rolls-Royce Merlin 621 or 623 engines. A modification of the Tudor 1 to meet BSAAC requirements. Fuselage 

lengthened by 1.83m and accommodation for 32 passengers. Four aircraft originally ordered. Subsequently augmented by conversion of 

BOAC Mk Is.
Avro 688 Tudor 4B. Two Tudor Is of BOAC contract modified to have lengthened fuselage of the Mk 4 for use by BSAAC, but retaining 

the flight engineer's station as on Mk I. Accommodation for 28 passengers.
Type 689 Tudor 5. Four Rolls-Royce Merlin 621 engines. A modification of the Tudor 2, of which six were completed, five for BSAAC. 

Accommodation for 44 day or 36 night passengers. BSAAC aircraft delivered without passenger seats and used on Berlin Airlift. Sixth 

airframe converted to have four Bristol Hercules 120 engines.



General Characteristics
Crew: 5 (two pilots, flight engineer, radio operator, navigator)
Capacity: 24 passengers
Length: 79 ft 6 in (24.23 m)
Wingspan: 120 ft 0 in (36.58 m)
Height: 22 ft 0 in (6.71 m)
Wing area: 1,421 ft² (132 m²)
Loaded weight: 66,000 lb (30,000 kg)
Max. takeoff weight: 76,000 lb (34,500 kg)
Powerplant: 4 × Rolls-Royce Merlin 100 12-cylinder V12 engines, 1,770 hp (1,320 kW) each


Performance
Maximum speed: 320 mph (512 km/h) at 8,000 ft (2,440 m)
Cruise speed: 283 mph (453 km/h) at 12,000 ft (3,660 m)
Range: 3,630 mi (5,840 km)
Service ceiling: 30,100 ft (9,180 m)
Rate of climb: 990 ft/min (5 m/s)
Wing loading: 53.5 lb/ft² (261 kg/m²)










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