Avro 688 Tudor
Avro 689 Tutor
The original Type 688 Tudor was designed 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.
As planned, the Tudor was to be a modification of the Lancaster IV (later the Lincoln) with a 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 1944 and in 1945.
When the prototype first flew on 14 June 1945 there were problems in pitch stability that required major modifications to the tail surfaces, and BOAC insisted on a further 357 modifications.
By time the first version of the Tudor was available in its production form, the 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.
Although the plane received an airworthiness certificate in November 1946, BOAC recognised that it was no competitor for the Constellation already being operated across the north Atlantic by TWA and Pan Am, and BOAC cancelled its order.
Avro did sell six to British South American Airways, but before BSAA had commenced operations in 1947, the prototype Tudor 2 - designed for shorter-haul operations with more passengers - crashed, killing both test pilot and designer. Six months later, in January 1948, BSAA’s Star Tiger took off from the Azores for Bermuda and was never heard from again. The Tudor’s passenger certificate was later withdrawn after a second mysterious crash in January 1949.
Aviation Traders proposed modifications for the Tudors of three types: the replacement or strengthening of any part of the equipment that could have contributed to the unexplained crashes; the effective lightening of the aircraft (by nearly a ton) by the removal of all sorts of unnecessary brackets and fittings; and the installation of up-to-date passenger facilities. Probably the most important of these many modifications was the bringing of the original Merlin 621 engines up to 623 specifications, to give increased take-off power, and the replacement of the entire landing gear with new Shackleton undercarriages. The proving flight for the first AT Tudor was on 14 February 1954. Laker could not get a War Office contract to carry troops, and was forced to devote his entire fleet of five, modified by fitting large freight doors, under the name Super Trader, to freight flights. After two fatal crashes in 1959 it was clear that the aircraft should be withdrawn.
The Tudor I was designed for only 12 passengers, but later models could carry 80. In total only 11 of the longer, wider Tudor 2, 5 and 11 models were built.
Avro 688 Tudor 1
Powered by four Rolls-Royce Merlin 102, 621 or 623 engines. 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. 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.
Avro 688 Tudor
Engine : 4 x Rolls Royce Merlin 100, 1613 hp
Length: 79.396 ft / 24.2 m
Height : 21.982 ft / 6.7 m
Wingspan : 120.079 ft / 36.6 m
Wing area : 1420.848 sq.ft / 132.0 sq.m
Max take off weight : 76072.5 lb / 34500.0 kg
Max. speed : 299 kt / 554 km/h
Cruising speed : 259 kt / 480 km/h
Initial climb rate : 984.25 ft/min / 5.0 m/s
Service ceiling : 31529 ft / 9610 m
Cruising altitude : 22507 ft / 6860 m
Wing load : 53.51 lb/sq.ft / 261.0 kg/sq.m
Maximum range : 4240 nm / 7852 km
Range : 4028 nm / 7460 km
Range (max. weight) : 3542 nm / 6560 km
Crew : 5
Armament : 12-24pax
Avro 689 Tudor 2
Engines: 4 x Rolls-Royce Merlin 621, 1320kW / 1,770 hp
Take-off weight: 36280 kg / 79984 lb
Empty weight: 21000 kg / 46297 lb
Wingspan: 36.58 m / 120 ft 0 in
Length: 32.18 m / 106 ft 7 in
Height: 7.39 m / 24 ft 3 in
Wing area: 132.01 sq.m / 1420.94 sq ft
Max. speed: 475 km/h / 295 mph
Cruise speed: 378 km/h / 235 mph
Ceiling: 7790 m / 25550 ft
Range: 3750 km / 2330 miles
AT Tudor / Super Trader
Engines: 4 x Merlin 623.