Sub-Contractors (1936-1945)


Supermarine’s Sub-contract department was responsible for managing the production of Supermarine designed parts and sub-assemblies under contract by other companies.

This ranged from small parts and sub-assemblies made to Supermarine’s specification, like the highly specialised main wing spar made by Reynold’s Tubes Ltd., to complete sections of the aircraft, like the tail and rudder assembly for the Spitfire made by Folland Aircraft Ltd.. It could even involve the sub-contracting out of the manufacture of entire aircraft as happened with Westlands, and later Cunliffe-Owen, who took on the manufacture of complete Seafire aircraft.

Sub contracting should be distinguished from the work performed by the Purchasing and Embodiment Loan departments. Purchasing being responsible for the purchase of tools, raw materials and non-Supermarine designed parts whilst Embodiment Loan were responsible for government supplied parts like the engine.

Sub-contracting The Spitfire

In order to meet the demands of Ministry of Aircraft Production (MAP) for their aircraft, in particular but not exclusively The Spitfire, and with their limited production facilities Supermarine became heavily dependent on sub-contractors for many of the parts of their planes.

For Vickers Armstrongs the sub-contracting of work for certain parts of the aircraft was a standard practice, for example the engine, propeller or detail parts and controls, but the sub-contracting of work on the actual air-frame to ‘competitor’ companies was not a particularly desirable practice and there was a certain degree of resistance at all levels of the company to the practice. Equally, the Ministry appeared to be almost completely oblivious to the implications of the requirement both in terms of the increased complexity of the supply chain and the resultant conflicting calls on the same sub-contractors from multiple companies, of which Supermarine was only one.

The result was what is best described as an unholy mess. The Ministry complained of delayed deliveries and there were many, particularly for the innovative wing leading edge assembly. Supermarine blamed the sub-contractors for not delivering the finished parts on time or for delivering them to an unacceptable standard. The sub-contractors blamed Supermarine for constantly changing the design and providing poor quality designs documentation. A Ministry investigation placed the blame squarely on Supermarine but their assessment should be viewed with a degree of caution since it was the Ministry who had insisted on the complex process in the first place and therefore would have to take some of the responsibility themselves were it to fail.

Perhaps the most obvious company names that spring to mind, when considering the non-Supermarine made parts of a Spitfire, were Rolls-Royce (who produced the Merlin, and later Griffon, engines),  and the de Havilland and ROTOL companies (who produced the propellers), however, these were not Supermarine sub-contractors as such, but rather government sub-contractors. These parts would be manufactured and then provided to Supermarine under the Embodiment Load process. That did not mean that they did not sometimes act as sub-contractors too, for example de Havilland also supplied washers.

Raw materials and machinery would also be acquired from a wide range of companies under standard purchasing, something that many companies were proud to include in their advertising and leading to some confusion between suppliers to Supermarine and sub-contract companies who made parts and sub-assemblies to Supermarine specification either because Supermarine did not have the expertise or required more than they could produce themselves.

There were literally hundreds of sub-contractors, often small companies, producing everything from tiny sub-component parts to major sections of the aircraft like the tail section or the wing leading edge. In many cases there were multiple companies supplying the same parts to keep up with demand or simply to avoid over reliance on a single source.

When it is considered that much of The Spitfire’s design was innovative, that mass production was an entirely new concept for Supermarine in the 1930s and this, combined with the numerous subcontracted parts that had to be brought together at the Woolston and Itchen Works, makes it not particularly surprising that The Spitfire had many “teething problems” in reaching production. However, in a curious irony it was Supermarines’ familiarity with this dispersed production process that probably helped enable it to survive the destruction of their Woolston and Itchen Works in September 1940 and subsequent dispersal of production into small, semi-independent, workshops all feeding into regional Final Assembly and Test Flight hangars.

At Castle Bromwich, where mass production was possible, there was still a massive supply chain of sub-contractors feeding into the factory. 

(1936-1939) Early Spitfire Production

List based on Morgan & Shacklady’s book ‘Spitfire: The History’ which includes a list of what they describe as “The main companies involved in producing large assemblies in the early days of production”

Unlike Webb’s later list it does not include those supplying materials like the tangun pipes, used in the manufacturing process by Supermarine themselves or the smaller (detail) parts and sub-assemblies.

Companies supplying Supermarine with the main Spitfire sub-assemblies during the early stages of production (1936-1938)

Singer Motors Ltd.Engine mountings
Folland Aircraft Ltd.Tailplane & rudder
General Aircraft LtdWings
The Pressed Steel Co.Wing leading edge
G. Beaton & Son Ltd.Wing ribs
Westland Aircraft LtdWing ribs

Wartime Spitfire Production (1939-1945)

The following list of sub-contractors is based of Denis Webb’s record of sub-contract companies supplying Supermarine during his time as Sub-contacts manager for Supermarine. To the list should also be companies like ICI who developed and manufactured the perspex used in the cockpit canopy hood.

When reading this list be aware that the list fluctuated, Webb recalled cutting the number of firms working as sub-contractors down from approximately 240 in 1942 to 136 in 1944. It also covers only those firms subcontracted to Supermarine, not the companies supplying the subcontract company with materials or sub-assemblies.

Sub-Contract Companies (1939-1945)

A Lege & Co LtdTools
Acme Showcards & SignsDope-on-frames
Acton Bolt & Fine Threads LtdSpecial Length bolts
Aero Engines LtdAilerons, elevators, tail wheel strut, assembly chassis pintles and machined parts
Aero Pipes & GlassTangum pipes
Aero Tanks Ltd30 & 90 gallon jettison tanks
Aeroplastics LtdPilot seats
Air Service trainingMain planes [wings]
Air Service TrainingSeafire conversions, aileron repairs, spar webs
Airports LtdTools for TDO
AL Davenport LtdTungum pipes  
Albert Man EngineeringMachined details
Albert Optical CoVent pipe fairings
Albert Phillips Ltd30 gallon jettison tank
Alltools LtdMachined details
Aluminium Plant & Vessel LtdElectron fuel tanks & oil tanks, 30 gallon jettison tanks
Alvis LtdLink assemblies, cannon gun mounting (front)
AMD Engineering LtdPower & spring cylinders, radiator flap controls, machined details
AP Aircraft LtdTail planes, cowling panels, fuselage panels etc.
Associate Pumps LtdMachined details
Austers Ltd30 gallon jettison tank
Austin Neneer LtdBlisters
Autometalcraft LtdTropical air cleaners, 30 gallon jettison tanks
Avimo LtdMachined details
B Saxton & Co30 gallon jettison tank
Bar Productions LtdBolts
Barton Motors LtdSockets
Bayham Tools & Engineering CoDetails
Bell Precision LtdMachined details
Bell Punch LtdChassis operating units, control columns, machined details
Blackburn AircraftPressings
BluemelsPlastic details
Boon & Portermachined details for ‘Seafire’
Bowden EngineeringIndicator cables
Bratt Colbran LtdRadiator fairings, wings tips Mk VII, tropical equipment
Bristol TramwayMachined details
Bristol Tramway & Carriage CoMachined details
British IndistructoBaloon Hoods
British Power BoatPRU oil tanks
British Salmson Aero Engines LtdChassis operating units 
British Thomson-Houston Co Ltd (BTH)Engine Mountings,Main Bulkheads, machined details
British Thomson HoustonCompletion of leading edges, drilling spars, booms etc.
Bruntons LtdSections
Burman & SonsGun mountings (rear), wing bolts, machined details
Burndept LtdFerrules
BX PlasticsPlastic details
Byfleet Precision Tool Co LtdTools
Carbodies LtdBottom front cowling panel pressings
Carter & CoMachined details
Cen Trup Ltd30 gallon jettison tank
Charlsworth Bodies Ltd30 gallon jettison tank
Chilton AircraftMachined details
Claudet LtdMachined details
Clifford Aero & AutoTrimming jacks & machined details
Coag Ltdscrews
Compton EngineeringDetails
Coopers Mechanical Joints LtdGuards
Courtauld InstituteWing assembly jig items
Cramic EngineeringMachined details
Cromwell Industries170 gallon jettison tanks
Crouch Engineering90 gallon jettison tank 
Cunliffe Owen AircraftSeafire oil tanks
David Brown & SonMitre Wheels
DCT Engineering CoMachined fittings
De Havilland AircraftWashers
Denton Sheet metal Co30 gallon jettison tank
ED Abbot LtdRadiator flaps & sheet metal details
Edward Williams LtdMachined details
EG Brown & Co29 gallon PRUF tank special for long range conversion
Elfords garageMachined details
Elliott BrosWoodwork Details
Elliott Windscreens LtdMachined details
Ellisons Insulators LtdRollers
Essanbee LtdMk XII oil tanks
Essex AeroElectron fuel tanks & oil tanks, 30 gallon jettison tanks
Excelsior Motor Radiator Co. LeedsWindscreens, baloon hoods, aft windows, oil tanks, chassis fairings, machined details
Excelsior Motor Radiator Co. SheffieldWindscreens, baloon hoods, aft windows, oil tanks, chassis fairings, machined details
F Cheverton LtdMachined details
Fairey Aviation LtdFasteners
Faulkners LtdDetail parts
Fletcher BrosPressings for ribs, booms, frames, ailerons, elevator spar etc.
Folland AircraftStern portions, ailerons, rasing  and operations gear for seats, machined parts and sheet metal details
Forgecraft LtdTungum pipes for Glycol & oil Systems
Forward Radiators LtdOil reservoirs, oil cooler fairings, duct pressings
Foster Wickner AircraftPlastic details
FW Tomkinson LtdPlastic moulding
G Beaton & Sons LtdMain fuselage frames, main plane ribs, rear trailing ribs, rear & auxiliary spars, sheet metal details, machined parts
G Johnson BrosEngine Mountings, slings
General Electric Co. (Airfied Research Grp)Wing Tips (Airfied Research Grp)
General AircraftMain planes, tail planes, stern portions, flaps, wing tips and some sheet metal details
GH Gregory LtdPlastic details
Glover & Main LtdGun mountings (front), machined details
GN Haden & SonRib brace fittings, oil pipes
Government Training CentreMachined details
Great Western RailwayMachined details
Guest & Chrimes LtdMachined details
H & E Lintott LtdDrill Jigs
Halex LtdPlastic details
Hall Telephone AccessoriesBolts & connecting rods
Hamilton BrosMachined details
Hampshire Car BodiesMachining & Assembly
Hanwell EngineeringSpecial plain length bolts
Harborough Aircraft Construction CoGun mounting supports (front)
Harris & Sheldon Ltd30 gallon jettison tank
Heatrac LtdHeater Casings
Helmets LtdPlastic assemblies
Herman Smith Ltd30 gallon jettison tank
Heston AircraftMain bulkhead, ailerons, raising and operating gear for seats, machined part and sheet metal details
Hickman (1928) Ltd30 gallon jettison tank
Hill Adams LtdStruts
Holyroyd & CoTools
Humphris & Son LtdMachined details
Hunt & CoMachined details
Huntley & SparksSlinging apparatus
Intertype LtdMachined details
Invicta Radio LtdChassis indicator lamp units
J & E Hall LtdRib attachment fittings
J Gibbons  (James Gibbons?)Details
J MarstonMarang bag banks
J Norton & CoHandwheels
JC Dyas ltdEngine & Hub covers
John Heathcote LtdMachined details
Joseph Lucas LtdCable harness, nut rings
John P White & SonsDihedral boards, incidence boards
JS White & Co Ltd [J. Samuel White and Co]Main fuselage frames, radiator flaps, rudder pedal assembly, 90 gallon jettison tanks
Kingsbury EngineeringMachined details
Kolster-Brandes LtdChassis indicator lamp units, chassis emergency lowering control, throttle contactor, tail adjustment indicator, tail lamp cover & fairing
Lakeside EngineeringPressings
Lancefield Coach WorksTungum pipes
LAW Engineering CoBolts & needles
Lazgill Aircraft CoConecting rods, pulley guards
Lea-Francis LtdElevator cross shaft, rudder levers, machined details
Lee & Wilkes LtdGun heating pipes 
Leeds Metal SpinningsGun fairings 
Leverstart LtdBonding terminals
Linoleum Manufacturing CoMachined details
Longfleet Motors & Engineering LtdTrimmer jacks, machined details and jig parts
Macfarlane Thirsk LtdMachined details
Maintenance Unit, RAF KidbrookeRudder assembly jigs
Maison Fittings ltdPlastic details
Martin Baker A/CJettison hood gear (Webb) Armoured seats (GG)
Mass Products LtdMachined details
Mattehw Hall & CoMachined details for jettison tanks
Matthew Hall LtdSmall machined parts
Metal Box LtdLink chutes, feed necks
Metal ComponentsAileron control drum, detail plate fittings
Metal propellors LtdMachined details
Modern Products LtdDistance tubes
Molins Machine CoDetails
Morrison EngineeringPilot seat raising & operating gear
Motor Panels LtdTropical oil tank, 30 gallon jettison tanks
Oddie Bradbury & CullMk VII wing tip details
Opperman PrecisionPower cylinder & spring cylinder
Osler & Faraday LtdPlugs & Sockets
Park Ward LtdAir intakes in sheet metal
Parnall AircraftMain planes, ailerons, fuel tanks, oil tanks, chassis jacks, tail wheel assembly, wheel fairings, radiator fairings, flaps, tail planes, elevators, rudders, baloon hoods, oil cooler fairings, machined details
Patent Lighting CoDipstick seatings
PB Cow & CoRubber covers (PRU)
Perfecta MotorsRudder pedal assembly & machined details
Phillips & Powis LtdEngine mountings Mk XII
Pirelli General Cable WorksMachined details
Pobjoy Air MotorsMain planes, rudders, machined details
Powers Accounting MachinesWelding
Precision EngineeringMachined details
Pressed Steel CoLeading edge skins, stiffeners, tank cowls, radiator fairing pressings
Pullman Spring Filled Co30 gallon jettison tank
Purefoy EngineeringTail wheel struts, tail wheel jacks & details
R & J Park & CoWooden cases for overseas shipment
RJ Shanks & Co LtdMachined details for chassis locks, radiator flap control assembly & details
R Malcolm LtdWing Tips, standard & Mk VII
RAF No.13 MUJig details
Range Boilers LtdTungum pipes
Ratcliffe EngineeringDetails for assembly jigs
Redwing AircraftMachined details
Reynolds Tube LtdMain spar booms
Rodds GarageMachined details
Rolls Razor LtdControl Columns
Romsey precisionBolts
Ronald Trist LtdTail wheel jacks & machined details
Ross Courtney LtdTee pieces & details
S Parkes & CoMachined details
Saunders-Roe LtdVarious experimental parts
Scottish AviationFlaps, machined and sheet metal details
Screw Machine Products LtdSpecial bolts
Sellman & Hill30 gallon jettison tank
Serck RadiatorsHeader tanks, radiators & oil coolers
Singer Manufacturing CoMachined details
Singers Ltd (Singer Motors Ltd)Engine Mountings, aileron control drums, chassis jacks, chassis operating units, elevator cross shaft, machined details
Skinners LtdMachined details
Sm Stuart Turner & CoMachined details
Smart Sheet Metal WorksUpper & Lower Air Chamber
Smith Motors Ltd30 gallon jettison tank
Southalls LtdBolts
Southampton Metal & Wood Industries30 gallon jettison tank
Southern Aircraft Ltd30 gallon jettison tank
Southern Engineering CoMachined details
Southern Railway Carriage & WagonMachined details
Sparton EngineeringMachined details
Spencer & Sons LtdOxygen bottle mountings
SS Cars170 gallon jettison tanks
Stanley Engineering CoMachined details
Stewart & Arden Ltd30 gallon jettison tank
Stuart Turner LtdMachined details
Sun Engineering CoMachined details
Sunbeam TalbotSpar web pressings
TB Morley & CoFork Ends
The Container Box & Printing Co30 gallon jettison tank
The Gramaphone Co.Special plain length bolts
The Mersey Jig & ToolRiveting toggles
Thecia EngineeringMachined details
Thomas HarringtonDetails
Triplex Saftey Glass CoHood Panels
Tubular FurnitureStay tubes
Tudor EngineeringDetails
Turner & Savage LtdCowling panels, sheet metal work
Twyford EngineeringSockets
Underwood ElectricBolts
US ConcessionariesBolts
Vactric LtdSpecial bolts
Vickers-Armstrongs, WeybridgeMain oleo legs and tail oleos
Vokes LtdOil filters
Vulcanised Fibre ltd30 gallon jettison tank
W Deakin & CoCover plates, retaining plates, washers
W Parkinson LtdRadiator flaps, 90 gallon jettison tanks
WA Williamson & CoBottom fuel tanks
Wadham Bros. LtdTropical & Mk IX oil tanks & sheet metal details, bomb racks etc.
Wallis Tin StampingTropical cowling, oil cooler fairings, metal covering for ailerons, 30 gallon jettison tanls
Warwick AviationGun heating pipes, 30 gallon jettison tanks & various spinnings
WB CowanAileron control levers
Webber, Sawyer & BrownMachined details
Weir precision LtdMachined details
Westland AircraftMain planes, rudders, wing tips, flaps, machined parts, main plane ribs, sheet metal details
Whatton & SonSpool Struts
Wickham Tool CoTail adjustment indicators
Wilkinson Rubber CoCovering pipes with petrol resisting rubber
Williams & WomersleyMachining & assembly of tools
Williamson ManufacturingFerules
Windover LtdPilot Seats
WJ Wild LtdWashers
Wrighton Aircraft CoSpecial wood elevators
WT Clarke & CoGun fairings, metal spun items
WT French & SonHousing
Wyagood-Otis ltdAttachment Fittings
Wycliffe Foundry CoSprockets
Yeovil Sheet Metal CoAssemblies
Zephyr EngineeringRib brace fittings

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