| M.57 Aerovan | |
|---|---|
 Aerovan 4 of Channel Islands Air Freight atManchester (Ringway) Airport in May 1955 | |
| General information | |
| Type | Short haul transport |
| National origin | United Kingdom |
| Manufacturer | Miles Aircraft |
| Designer | |
| Status | retired |
| Number built | 48[1] |
| History | |
| First flight | 26 January 1945 |
| Variants | Miles M.68 Hurel-Dubois Miles HDM.105 |
TheMiles M.57 Aerovan was a British twin-engined short-range low-cost transport aircraft designed and produced byMiles Aircraft. It was primarily used for freight and passenger services.[2]
Development of the Aerovan started during the latter years of theSecond World War as an affordable freighter suitable for both civilian and military purposes. It was suited to austere operations, and possessed an atypically high payload capacity for its power output. Relatively large payloads, including a single car, could be transported by the aircraft, being loaded via its largeclamshell freight door. While Miles intended to produce the Aerovan for theBritish Army as a wartime asset, development was put on hold by order of theAir Ministry until the end of the conflict.
On 26 January 1945, themaiden flight of the Aerovan took place. Quantity production formally commenced during 1946, although customer demand exceeded the company's production capacity. The Aerovan was primarily flown by commercial operators, but was also operated by a number of military users. Numerous variants were developed, and further models were envisioned, including aflying boat model; however, production was halted as a result of the company'sbankruptcy in late 1947.
Work on the Aerovan commenced during early 1944, being envisioned from the onset as a low-powered affordable freighter that was suited to both civilian and military purposes.[3] Throughout theSecond World War, George Miles had advocated for the use of such an aircraft within the British military in place of the then-standard practice of largely relying ongliders. Following the completion of theMiles Messenger's development, it was felt by Miles' design team that an aircraft of roughly double the power and weight would be a valuable pursuit; in particular, it was believed that such an aircraft would be a capable military transport for theatres such as theBurma campaign againstImperial Japan, as well as working in niche roles such as anair ambulance.[3]
To suit its intended use, it was recognised early on that such an aircraft would need to be operated from austere airstrips and less hospitable terrain.[4] Furthermore, it was recognised that the type could be subsequently scaled upwards into a larger freighter, of which Miles had formulated multiple proposals even prior to the conflict's end. Beyond its military applications, the comingpost-war era would see civilian operators that would need large numbers of economic short range transports and small freighters.[5] A high-wing configuration selected for the aircraft, being fitted with external aerofoilflaps and powered by a pair ofBlackburn Cirrus Major piston engines. To facilitate easy loading, the entire rear of the fuselage was a door, necessitating the use of a relatively high tail boom.[5]
The prototype was constructed at Miles'Woodley factory inBerkshire. On 26 January 1945, this prototype conducted the type'smaiden flight, piloted by Tommy Rose.[6] The performance of the prototype was immediately positive, proving to be both comfortable and relatively easy to fly. It proved to have an atypically high payload capacity for an aircraft of such power, being capable of lifting payloads in excess of its own weight when operated in a bare configuration.[7] The results of the initial trials were submitted to theAir Ministry as the company prepared to put the Aerovan into immediate production to support the war effort. However, Miles' work was not met with approval, the company beingcensured for building the aircraft without authorisation and work on the project was suspended on the ministry's orders.[8]
Work on the Aerovan was resumed shortly afterVictory in Europe Day.[8] While there was immediate demand for the type amongst civilian customers, Miles were not able to keep up with the rate of orders incoming, an outcome which aviation author Don Brown attributed to the Air Ministry's decision to place the project on hold. The production model of the Aerovan featured some changes from the prototype, including an 18-inch stretch of the fuselage and the use ofporthole windows rather than rectangular ones.[8] Quantity production of the Aerovan properly commenced during 1946; the majority of aircraft sold were to civilian operators, both domestic and overseas, although some military customers, includingIsrael andNew Zealand, also emerged for the type.[9]
Following negotiations, alicence was granted for the Aerovan to be manufactured in France, but no such aircraft were ever manufactured in the country. A singleRoyal New Zealand Air Force (RNZAF) aircraft was converted foraerial fertiliser spreading, while a second for aeromagnetic survey work, although it proved to be unsuccessful.[10] A single Mark 4 was used for research with aHurel-Dubois high aspect ratio wing in 1957, being then known as theMiles HDM.105.[11] The prototype, which was retroactively designated the Mark 1, was later fitted with a 5/6th scale replica of theArmstrong Siddeley Mamba turboprop nacelle for theMiles Marathon; it was also subsequently outfitted withailerons in line with the standard flaps.[12]
Even prior to the Aerovan entering quantity production, Miles had ambitions to produce multiple derivatives of the type. One such design was a specialised aircraft for theair observation post role, intended to be operated by a four-man crew and featuring an enlarged glazed canopy to provide an all-round view in combination with a glazed rear fuselage section.[1] Work was also undertaken on aflying boat derivative that would have had a single-step hull, keeping the rear freight door above the waterline with the assistance of two stabilisingfloats carried on outriggers set on either side of the hull. Both designs would have retained significant commonality with the standard Aerovan, sharing the wing, tail, and powerplant arrangement.[1] Production of the Aerovan was abruptly terminated during late 1947 as a consequence of Miles'bankruptcy and subsequent dissolution.
The Miles Aerovan was a twin-engined high-wingmonoplane of plastic-bonded plywood construction with some spruce and metal parts. It had a fixedtricycle undercarriage, three vertical tail and rudder units, one central and two as tailplane endplates, the configuration being generally reminiscent of theMiles Messenger.[6][5] The wing featured electrically actuatedflaps that could be adjusted to any angle, which were a recent innovation. On the ground, steering was achieved either by differential braking or differential operation of the throttles.[5]
The Aerovan had a relatively deep-sided forward fuselage, which necessitated the use of a large fin area.[5] A pair of pilots were accommodated within a large clearperspex canopy which formed the front dorsal part of the pod, while the pod-shaped fuselage was lined with four or five circular windows on either side for use by passengers. Access to the cabin and cockpit was via a door on the starboard side.[5] For additional comfort, amenities such assoundproofing were typically installed.[13] The Aerovan's lifting capabilities were such that payloads could weigh up to one tonne, along with sufficient volume to enable the carriage of a typical familycar, which could be loaded through theclamshell doors set to the rear.[6][13]
Various aspects of the Aerovan's configuration could be adjusted to meet customer demand; such alterations included the addition ofskis for operations within snowy climates.[14] The standard Aerovan was powered by a pair ofBlackburn Cirrus Major piston engines; alternative powerplants included thede Havilland Gipsy Major and theLycoming O-435, often necessitating the use of enlarged fins and rudders to cope with the increased power under all circumstances. By swapping the engines, the maximum speed could be increased by up to 20 mph and the rate of climb by up to 50 per cent.[15]
The Aerovan was principally operated by civilian customers, with demand for the type from such operators outstripping Miles' production capacity. These aircraft were often used for a diverse range of operations; more obscure uses included the movement oflivestock across theEnglish Channel and as a flyingremoval van.[16]
The majority of Mk 3 and 4 Aerovans were employed on passenger and freight services, charter work and joyriding in the UK and in theNear East. Meridian Air Maps operated Aerovan 4G-AISF onaerial survey work from October 1955 until it crashed on takeoff fromManchester (Ringway) on 29 April 1957.[17] The accident resulted in the deaths of two passengers and pilotJean Lennox Bird, the first woman to receive RAF wings.[18]
The RNZAF evaluated a pair of Aerovan 4s during 1950.
The newly formedIsraeli Air Force acquired a single AerovanG-AJWI from Britain, which entered service during June 1948. Able to use relatively short landing strips, it was repeatedly flown into settlements and Jerusalem airport in the face of defensive rifle fire. On 17 July 1948, the aircraft made a forced landing south ofTel Aviv and was destroyed by Palestinians.[19]
Source:[20]
Sources:[29]
Data fromBritish Civil Aircraft since 1919[30]
General characteristics
Performance
Related development
Related lists
