Postcards from Slough
Postcards from Slough

ML Aviation

Wrightson Aircraft Sales was founded in 1934 at 601 Bath Road, Slough Trading Estate. It later became Malcolm and Farquharson in May 1936. Later still, in December 1936, R Malcolm & Co was founded out of the company. In December 1939 Malcolm & Farquharson became a holding company with aircraft component production carried out by R. Malcolm.


At the beginning of the Second World War, Malcolm & Farquharson and R Malcolm were in financial difficulties and approached the Mobbs family for assistance. Noel Mobbs was co-founder of Slough Trading Estate with Sir Percival Perry in the early 1920s. During 1940 control of both companies was taken over by the Mobbs family through United Motor Finance Corporation.


R Malcolm & Co were aircraft sheet metal manufacturers. In 1938 the company was making petrol tanks, engine bearers, undercarriage legs and other items for the Tipsy Trainer. The company also made wheel spats, wing fillets and other components for the Miles Magister training aircraft. During the war the company made main plane fillets, tail plane leading edges and other parts for Spitfires. The company had to extend its premises and install new equipment to cope with the demand from the aviation industry at that time.

Miles Magister

The image represents an exhibit on display at the Museum of Berkshire Aviation at Woodley

The Malcolm Hood

This was a kind of cockpit canopy that was first developed and manufactured by R Malcolm & Co for the Spitfire. It was radical because of its bulged shape. It was vacuum-formed from an acrylic material which had the advantages over glass of being lighter weight and could be shaped to give a better all-round visibility for the pilot.


In manufacture, a sheet of acrylic is secured to a female mould and the assembly is heated in an oven until the acrylic is pliable. The air is then sucked from the mould and the acrylic sheet is drawn into it, forming the shape of the canopy. The acrylic is then trimmed and attached to an aluminium or composite frame.


The author believes that R Malcolm & Co approached a company called Pytchley Autocar Co Ltd who, in 1937, was making sliding panels which fitted flush when closed. This feature was obviously a necessary requirement for the Malcolm Hood.


The concept of the Malcolm Hood was further developed for other aircraft such as the North American produced P-51B & C Mustang variants as retrofit items. The work being carried out at White Waltham. It was later used as standard on later versions of the Vought F4U Corsair and countless aircraft types ever since.

The image represents a half-opened Malcolm Hood fitted to a Supermarine Spitfire Mk IIa. When the hood is pulled forward into place it would drop down and lock so that the front and rear will end up flush with the respective fixed parts of the cockpit.

Marcel Lobelle (c1893–1967)

In 1940 Belgian aeronautical engineer Marcel Lobelle, chief designer at Fairey Aviation, left the company to join R Malcolm. Lobelle was born in Kortrijk, Flanders, fought in the Belgian Army at the start of World War I, with the 1st Regiment of Grenadiers.


Lobelle was seriously wounded in the fighting for Tervaete during the Battle of the Yser in October 1914. On being discharged from the army in 1917, he moved to Britain, taking employment with the Tarrant Company, and then Martinsyde, before eventually becoming chief designer at Fairey Aviation. Among his aircraft designs whilst at Faireys was the Swordfish, Fulmar, Albacore, Barracuda and Firefly II.

Swordfish at Duxford 1987

Lobelle set up a drawing office on Slough Trading Estate. Demand was growing rapidly for aircraft and aircraft component production from the Ministry of Aircraft Production. To allow for expansion the drawing office and experimental work was moved to White Waltham. Manufacturing remained on the Slough Trading Estate still under the name of R. Malcolm. An additional firing site was also established on the airfield perimeter for development work.


In 1943, Malcolm & Farquharson's services were dispensed with. Control of R Malcolm was taken over Eric Mobbs as Managing Director and Marcel Lobelle as Chief Designer. In 1944 Lobelle was appointed a director of the company. In October 1946, the name was changed to ML Aviation for the White Waltham site and ML Engineering at Slough, the initials being taken from the managing director and chief designer.

Following the end of the Second World War, many companies suffered from falling and cancelled government military contracts. However the coming of the East and West Cold War brought more work for ML Aviation and ML Engineering and through the 1950s the companies continued to expand.


The expansion required finance and so 1958 ML created the public company ML Holdings. This new company diversified into non-aerospace business which generated more finance. It was a golden age for the company.

From the 1950s, ML Aviation designed and built an extraordinary range of systems, accessories and equipment for the aviation industry especially for military applications. From the 1950s, ML Aviation designed and built an extraordinary range of systems, accessories and equipment for the aviation industry especially for military applications. The following list represents a fraction of the company’s activities:

  • Helicopter and Aeroplane Ground Handling Equipment

  • Shipborne Helicopter Restraint Systems

  • Weapon Handling Equipment

  • Airborne Weapon Ejector Release Units

  • Practice Bomb Carriers

  • Tactical Bomb Carriers

  • Runway/Road Surface Fiction Meters (Mu Meters)

    The company also made components for Polaris missiles.

The 1980s however, found a big reduction in the aerospace industry and this had a considerable impact on ML Aviation and its workforce. In 1990, the Holdings Board bought Wallop Industries. The company merged the operations at White Waltham site with Wallop Industries based in Andover. The site at White Waltham was sold in 1996.


 In 1996, the Holding Board acquired other companies such as Frazer Nash and merged them with ML Aviation. ML Engineering in Slough moved to Andover in 1997 enabling design and production to join under one roof. In 1997 Cobham plc acquired ML Aviation & Marine for £37 million.

Ejector Release Units (ERUs) are used to carry and release stores such as bombs and missiles from military fighter and fighter-bomber aircraft. ML Aviation made a number of different types tailored for different aircraft and stores types. Other types were designed to release brake parachutes. This article covers some detail on the No 120 ERU.

No 120m 30in Ejector Release Unit

This unit carried and ejected stores over 1,400 lbs and was used on Buccaneer, Jaguar and Nimrod aircraft. It was the standard 30 inch ejector for the RAF.

The 120 series Ejector Release Unit is a heavy duty unit for the ejection of 1,000 lb and 2,000 lb NATO stores from fast jet or large aircraft. The ERU series provided low weight and high strength in service around the world for over 20 years prior to this statement. It can be used in aircraft bomb bays, fuselage stations or wing pylons.


The ERU 120 features 14” and 30” lug spacing and the recommended cartridge is CERU 204. The unit weighs 67 lb and its dimensions are 813 x 77 x 204mm.


CERU204 Mk3 cartridges are used to provide gas pressure to operate Ejector Release units. They consist of an aluminium alloy case, a main propellant charge, an ignition element and a closure disc.


An electrical signal from the cockpit of the carrying aircraft ignites the main propellant charge. The closure disc is ruptured and the released gas actuates the ejector mechanism. The bomb or store is thrown down safely out of the path of any trailing parts of the aircraft such as the tail plane.

From Cobham website


The Sprite electronic surveillance vehicle was powered by two 6hp Piper 2/80 2-cycle engines and lift/propulsion was by contra rotating rotors which meant the machine didn’t need any tail arrangement. It had a fuel capacity of 6kg giving an endurance of 2·5 hours.

ML Aviation SPRITE or Surveillance Patrol Reconnaissance Intelligence Target Designation Electronic Warfare first appeared in 1981

Other specifications

Body diameter: 650mm

Rotor diameter: 1·6m

Height: 900mm

Maximum mass: 36kg

Speed range: Hover to 110kms/hr

Operational altitude: 250-500m

Ceiling: 3,000m

Ceiling: 3,000m

Marcel Lobelle rest peacefully

Marcel Lobelle died at Wexham Park Hospital on 30 August 1967. His death certificate records that he was aged 74 and he was married to Doris.


Many thanks to David Wiltshire for providing the lead on this article and also on Modern Wheel Drive (MWD).

Further thanks to the Museum of Berkshire Aviation, of which I am a member, for help, support and guidance on this and other articles. This website has a section on many aspects of the museum and the volunteers who work there. It can be found by clicking the tab above the header of any page of this website.


For the latest information, opening days, times and the location of the museum, visit the homepage of the website by clicking on the button below:

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