Sunbeam Works Racing cars participated in the 1922 XVI Grand Prix de l'A.C.F. in Strasbourg. The race took place on 15 July 1922 and was run to a formula stipulating that maximum engine capacity should not exceed 2 litres and that the cars should be two-seaters weighing not less than 650 kg. The formula was to remain in force for four years producing "fields of brilliance to be unequalled for many years" it was the first rolling massed start in the history of Grand Prix motor-racing.
Three Ernest Henry-designed team cars were constructed for the event preceded by a similar prototype which served as a test, practice and spare car. When H.O.D. Segrave's assigned team car's engine was ruined by fire during practice he adopted the prototype instead as his race car.The Boys’ Life of Sir Henry Segrave, Capt. Malcolm Campbell and J Wentworth Day p. 80Sir Henry Segrave, Cyril Posthumus, 1961 p. 87Motor Sport 1979 August William BoddySunbeam Talbot Darracq, Journal of the STD Register, Number 180 Winter 2007, Oliver Heal and Bruce Dowell, pp. 31–35 During the race the engines in all three Sunbeam cars failed and none finished.
After the Grand Prix one of the Sunbeam cars was entered in a Brooklands race, which it won. All four cars were subsequently sold to privateers and entered in various events with varied levels of success. Rarely for a complete British Works team of the Vintage era, all four cars survive. However, only one - chassis No 2 - can be considered original, while the other three embody genuine and original components and possess continuous histories Directory of Historic Racing Cars, Denis Jenkinson, 1987 pp. 11–12
The course The course near the French city of Strasbourg was roughly a triangular of unpaved public roads with three near straights and three sharp corners. The start line where elaborate viewing tribunes and fronting ‘pits’ were built was at Duppigheim, first corner was at Entzheim, second at Innenheim, and final corner at Duttlenheim. It was long, requiring 60 laps to complete the .Grand Prix de L’A.C.F. Strasbourg 1922 75eme Anniversaire, Bernard Truche, 1997 pp. 9–17
The 1922 Grand Prix de l’ACF In practice it became clear that the Fiat team had superior speed; Sunbeam axle ratio were lowered to improve speed. In the race, the Sunbeams could not match the performance of the Fiats, safe engine revolutions were exceeded and the inlet valves fractured; the Sunbeams were ‘put out of running’. Jean Chassagne in car No.9, the team leader and winner of that year's IoM T.T. with a modified 1921 Grand Prix Sunbeam retired after only five laps as did K. Lee Guinness in car No.16.
Segrave, in car No.21, the junior team member, in his second ever Grand Prix lasted ‘approximately half the full distance’. He was later to remember this event as ‘sheer misery’ (not least due to chemical fuel burns on his backside sustained by fuel spillage, the result of a hurried and untidy refuelling); he did hold a fourth place behind the Fiats for most of his race.
1922 Brooklands On 30 September 1922 the Essex M.C. put over a series of Speed Championships. The 2-litre 8.5mile event was won in one of the Grand Prix Sunbeams by H.O.D. Segrave at 92.81 mph, fastest lap 99.81 mph. This was the only success these cars obtained for Sunbeam.
Aftermath The failure of the cars did irreparable damage to their designer Ernest Henry's previously shining reputation and career. Despite the mechanical weakness of its rear axle, the performance of the Fiat 804 convinced Louis Coatalen, Sunbeam's general manager, to use the design as inspiration for his winning series of Grand Prix cars between 1923 -1925.
The 1922 Sunbeam engines which failed during the race were repaired, the advanced servo operated brake systems were removed and installed in the 1923 Grand Prix Sunbeams. The gear lever was repositioned to the centre of the cockpit. A few years later after a ‘cooling period’ the cars were sold into private hands. All four 1922 team cars - including the prototype - survive today; a rare survival of a complete Grand Prix team of the vintage era. However, only one is original (Sunbeam No 2); the other three are genuine, authentic and resurrected (Sunbeam No 1, No 3 and No 4 respectively).
Design Designed by Ernest Henry in Suresnes, with input from Louis Coatalen and the Sunbeam Experimental Department Wolverhampton. Jean Chassagne was liaising and also in charge of testing.
Before the Great War Ernest Henry was a part of the successful and innovative ‘Charlatans’ who designed the first ever double overhead cams four valve Grand Prix engines for the 1912 Peugeot;The Classic Twin-Cam Engine, Griffith Borgeson, 1981 pp. 13–18 (many further mentions throughout the book) the 1922 Sunbeam design follows similar principles.The Classic Twin-Cam Engine, Griffith Borgeson, 1981 pp. 94–96 The aluminum body was the latest in streamlining and is typical of the Post Great War Henry design with the spare wheel carried longitudinally in the tail and braced by the large fuel tank.
The contemporary Wolverhampton Motor Car Registry records the prototype car being road-registered before three intended race cars followed as a batch. Each of the latter trio was finalised around its intended driver's requirements and preferences. The asymmetrically inclined valves (inlet 20 degrees and outlet 40 degrees from vertical) were a significant departure for Henry and may be attributable to Sunbeam and Coatalen whose interest in desaxé configuration dated to 1911. Another unusual detail was the engine mounted directly on the chassis frame similarly to the 1921 'invincible Talbot-Darracq'.
Following prototype testing at Brooklands and on the Isle of Man prior to the Grand Prix, modifications were instigated to the tail support bracket.The TASO Mathieson & K Taylor Photographic and Document Archive – DA6436 at Brooklands vs. DA6436 Strasbourg practice Different carburetor configurations and different tyre types were tried, axle ratios experimented with, aero screens and mudguards were installed or removed as required.
Colour / trim Body in British Racing Green, black wheels and black leather trim (fluted for team cars, flat panel prototype car).
Chassis Upswept chassis over front and back axles to lower centre of gravity. Three-piece machined and polished front axle; H section centre bolted to forged tubular end-pieces to resist torsional stress produced by front wheel brakes.Autocar 3 June 1922 p. 930 Front cross member as well as channel section amidships and rear form the frame. Underslung polished semi-elliptical Jonas Woodhead and Sons springs (STD subsidiary) all around. Hartford shock absorbers fitted each corner (single front, double rear).Automobilia 15 Julliet 1922 No 124 p. 22 High-geared worm and white-metal nut steering box with a cord bound spring-spoked steel steering wheel.The Autocar 3 June 1922 p. 930 Narrow streamlined all aluminium staggered two-seater body; spare wheel carried longitudinally in the tail. Louvred under-pan ran the length of the car. Wheelbase 8 ft 2 in, Track 3 ft 11in. Tyres tested at Brooklands and elsewhere prior to the 1922 Strasbourg Grand Prix on ‘Palmer Cord’ Beaded Edge 765x105 and similar ‘Dunlop Magnum Cord’. At Strasbourg during Practice leading to the G.P. ‘Dunlop Magnum Cord’ & ‘Dunlop Cord’ Beaded Edge 30x31/2. Raced in the Grand Prix on ‘Dunlop S.S. Cord’ Straight Sided 30x31/2 on split rim wheels.The TASO Mathieson & K Taylor Photographic and Document Archive
Weight J Chassagne 13cwt 84 lb K. Lee Guinness 13cwt 101 lb H.O.D. Segrave 13cwt 57 lb
Engine Ernest Henry designed four-cylinder desaxé (reducing thrust against cylinder wall during the "power" stroke) cast-iron monobloc set on a separate barrel-shaped cast-aluminum crankcase mounted directly on the chassis frame. Twin overhead camshafts carried in split housings on the fixed cylinder head and operate the sixteen valves through thimble tappets. Four valves per cylinder 60 degrees asymmetrically inclined (inlet 20 degrees and outlet 40 degrees from vertical). The double valve springs secured by split, tapered collets and collar. The crankshaft is a balanced built-up type running in three ball bearings. Oil pipes pass externally along the webs of the shaft and held in place by liberally drilled, semi circular steel plates screwed to the webs to counteract centrifugal forces acting upon the pipes. Steel, H-section, fully machined connecting rods are fitted with four big-end bolts. Plain white metal big-end bearings and bronze bushes small-ends were employed. Access for fitting of the big-ends is provided by two panels offside below the exhaust ports. Domed aluminum pistons with two compression and one scraper ring. Train of ten cascading gears at front of the engine operate the camshafts, magnetos, oil and water pumps. The crankshaft gear drives the two magneto gears at crank speed. The two to one speed reduction to the camshafts takes place at the first stage of the gear train; all the remaining gears between the first intermediate gear and the gears at the camshafts are idlers. Bore and stroke 68x136mm, capacity 1975.6 cc Timing: inlet valve opens 10 degrees before TDC and exhaust valve closes 18 degrees after TDC; Inlet valve closes 30 degrees after bottom centre and exhaust valve opens 52 degrees before bottom centre. Inlet valve opening period 220 degrees, exhaust valve opening period 250 degrees. Maximum ignition advance 35 degrees. Tappet clearance 006" and 008". Piston speed 3792fpm @ 4250rpm. Compression 6.5 to 1 in the Grand Prix but 7.6 to 1 with different pistons in post-Works Brooklands racing. Power output 88 bhp at 4200rpm. Maximum rpm on bench test 4600. Max speed approximately 100 mph. Petrol consumption approximately 13m.p.g. RAC rating 11.4 hp.
Carburation Twin 40mm horizontal Solex bolted directly on the manifolds in the Grand Prix but twin Zenith triple diffuser carburettors and barrel throttle Claudel-Hobson were also tried. Fuel feed by pressure from 60-gallon tank positioned by leather-lined nickel-plated steel straps at rear.
Ignition Twin Scintilla magnetos mounted on the front of the timing gear case operated via Vernier couplings at crank speed. Two plugs per cylinder, one centrally placed in the cylinder head, 10 degrees inclined to the vertical and the other placed nearside on the inlet side of cylinder head.Automobilia 15 Julliet 1922 No124 p. 22
Transmission Four forward and one reverse speed gearbox in unit with engine mounted directly on the chassis. Inverted cone fabric clutch carried on light ribbed steel flywheel. Hotchkiss drive; transverse driven by a worm gear reduction for servo motor braking system (removed after the G.P.). Open hollow propeller shaft with two Hooke – type universal joints at each end sloping upwards from gearbox to the rear axle. Straight cut crown wheel and pinion drive through a normal differential to the hollow half shafts. The crown wheel housing is offset towards the nearside. Gear ratio overall Top (14 tooth pinion, 55 tooth crown) 3.928:1; 3rd 4.6099:1; 2nd 6.383:1; 1st 10.942:1. Other ratio recorded 4.08:1.
Lubrication Dry sump lubrication. Pressure/scavenge cluster gear type oil pump driven directly from the gear train at front of the engine at near crank speed. High pressure lubrication is limited to the big – ends. Oil pressure is regulated through hand controlled visual feeds. Drain pipes in the valve covers returning surplus oil to the sump. Separate five gallon fabricated sheet brass oil tank slung under driver and riding mechanic seats.
Cooling Centrifugal water pump mounted on the front of the timing gear case and driven directly. Two branch pipe leads from the cylinder head to the radiator and four branch pipe from the pump to the cylinder jackets, entering on the exhaust valve side.