Avro 642 Eighteen
|Avro 642/2m (VH-UXD), c.1936|
As a follow on to the Avro 618 Ten the Eighteen was a larger aircraft but used a modified Avro Ten wing. The wing was moved to the shoulder position with the engines mounted on the wing and a new larger fuselage was used. When the design was completed in February 1933 it was the largest aircraft designed by Avro. The new fuselage was a fabric-covered welded steel structure with seats for 16 passengers, a baggage area and a toilet. The nose section was made of wood and originally had a semi-circular glazed front, although this was later changed to a more conventional-type windscreen. The wooden wing was designed to use any of the engines in the Armstrong-Siddeley family and the first aircraft was built with two Armstrong Siddeley Jaguar VID engines with four-bladed propellers. 
With an order from the Midland and Scottish Air Ferries the first aircraft was nearly complete by December 1933. Registered G-ACFV the aircraft performed official performance trials at Martlesham Heath and was then returned to Woodford Aerodrome when the nose was modified. On 6 April 1934 the G-ACFV was handed over to the customer and was then flown to Castle Bromwich to pick up the Prime Minister Ramsay MacDonald and the Secretary of State for Air Lord Londonderry. With the important passengers on board G-ACFV was flown to Speke Aerodrome so they could declare open a new air service between Glasgow, London and Belfast. At the same time Lord Londonderry named the aircraft The Marchioness of Londonderry. Following the ceremony the Prime Minister and party were flown to Heston Aerodrome in London. 
From 6 April 1934 the Eighteen was used with other aircraft on the Glasgow-London-Belfast service by Midland and Scottish Air Ferries. In May 1935 G-ACFV was sold to Brian Allen Aviation for use with a variety of associated companies including Commercial Air Hire and Air Dispatch Limited. CAH used the aircraft for excursions and joy riding duties while Air Dispatch operated a daily newspaper flight between London and Paris, and a passenger service at the weekend. Due to the increase in freight business the aircraft was fitted with a larger loading door. Last flown by Commercial Air Hire in June 1936, a sightseeing trip around the RMS Queen Mary, the aircraft was sold as VH-UXD to Mandated Airlines in Australia. She was destroyed in New Guinea on 21 January 1942 by Japanese military forces.
The four-engined second aircraft Registered VT-AFM was handed over on 12 December 1934 and named the Star of India. By arrangement with the Indian Government the aircraft was operated and maintained by Indian National Airways when not required by the Viceroy. The aircraft was taken over by the Royal Air Force as L9166 in 1937 for use by AHQ India and was dismantled at Delhi in 1940. It has been said that the performance of the four-engined plane was poor, even dangerous, due to the reduced wing area caused by the extra "power-eggs".
- Two 450 hp (336 kW) Armstrong Siddeley Jaguar VID engines mounted on the wings, one built.
- Four 215 hp (160 kW) Armstrong Siddeley Lynx engines, one built.
Data from British Civil Aircraft since 1919 Volume 1
- Crew: 2
- Capacity: 16 passengers
- Length: 54 ft 6 in (16.62 m)
- Wingspan: 71 ft 3 in (21.72 m)
- Height: 11 ft 6 in (3.51 m)
- Wing area: 728 ft2 (67.7 m2)
- Empty weight: 7360 lb (3345 kg)
- Gross weight: 11800 lb (5363 kg)
- Powerplant: 2 × Armstrong Siddeley Jaguar IVD, 450 hp (336 kW) each
- Maximum speed: 160 mph (258 km/h)
- Range: 600 miles (970 km)
- Service ceiling: 15500 ft (4275 m)
- Rate of climb: 970 ft/min (4.9 m/s)
- Related development
- Related lists
- Monk, D.E. (April 1963). "The Avro Eighteen". Air-Britain's Aviation Review (Air-Britain) 0 (1): 4–5.
- Jackson 1973, pp. 128-129
- Robertson 1987, p. 100
- Joubert 1964, pp. 104-108
|Wikimedia Commons has media related to Avro 642 Eighteen.|
- Jackson, A.J. (1973). British Civil Aircraft since 1919 Volume 1. London: Putnam. ISBN 0-370-10006-9.
- Robertson, Bruce (1987). British Military Aircraft Serials 1878-1987. Letchworth, England: Midland Counties Publications. ISBN 0-904597-61-X.
- Joubert, Air Chief Marshall Sir Philip (1964). Fun and Games. London, England: Huchinson & Co.