By William Pearce
Louis Coatalen was the chief engineer of the Sunbeam Motor Car Company in Wolverhampton, England. In 1913, Coatalen was developing a new aircraft engine called the Mohawk. The engine’s V-12 layout was a first for Coatalen and Sunbeam, and both were eager to test the design. With the combination of a new engine design, unreliable aircraft, and poor weather, a better way to test the Mohawk was devised by installing it in a Sunbeam race car. After some teething trouble, the resulting car, named Toodles V, set eight world speed-over-distance records at the Brooklands track in England on 11 October 1913. The car was driven by Jean Chassagne, and it had a top speed of over 120 mph (193 km/h).
In 1919, Coatalen and Sunbeam sought to create a special race car and remembered the successful combination of a light chassis and a powerful aircraft engine. To power the special car, Coatalen took the basic 325 hp (242 kW) Manitou V-12 aircraft engine and combined it with cylinder blocks (with integral cylinder heads) that followed the design used on the 200 hp (149 kW) Arab V-8 aircraft engine. The output of the engine was 355 hp (265 kW), and the car became known as the Sunbeam 350HP.
The 350HP’s engine had the same layout as the Manitou, with two banks of six-cylinders separated by 60 degrees. Each cylinder bank consisted of two three-cylinder blocks made of aluminum and attached to the aluminum crankcase. The two spark plugs in each cylinder were fired by magnetos. Two carburetors were positioned between the cylinder banks, with one carburetor supplying the air/fuel mixture for the front six cylinders and the other supplying the rear six cylinders.
The engine differed from a standard Manitou engine in that the crankcase did not have any provisions for a gear reduction. The bore was increased .39 in (10 mm) to 4.72 in (120 mm), which is the same bore as the Arab. The Manitou’s four-valve per cylinder, dual-overhead camshaft arrangement was discarded in favor of a three valve (one intake and two exhaust) per cylinder, single-overhead design, similar to that used on the Arab. The camshaft acted on a follower that opened the intake valve. Two separate lobes controlled the exhaust valves via rocker arms. The camshafts were driven at the front of the engine (as it was installed in the car) by a train of 16 gears total.
The engine had a 5.31 in (135 mm) stroke, but it is occasionally cited as 5.45 in (138.5 mm) or 5.59 in (142 mm). The discrepancy is on account of the master and articulated connecting rod arrangement. The master rod provided a stroke of 5.31 in (135 mm), but the articulated rods increased the stroke by .28 in (7 mm), to 142 mm. The 5.45 in (138.5 mm) figure is an average of the two strokes. To accommodate the slightly longer stroke, the cylinder blocks of the left bank were slightly taller than the right bank. The engine displacement if often cited as 1,118 cu in (18.32 L), which is calculated from the 5.31 in (135 mm) stroke. But the stroke difference resulted in the left bank displacing an additional 29 cu in (.48 L), giving the engine a calculated displacement of 1,147 cu in (18.80 L). A hand crank was used to start the engine. Tuned by Bill Perkins at Brooklands, the 350HP’s engine produced 355 hp (265 kW) at 2,200 rpm.
The engine was positioned in the car so that what would have been the propeller shaft faced the rear, and it was mounted to the car’s C-channel frame that was 4.75 in (121 mm) tall and 29.5 in (749 mm) wide. A radiator was positioned in front of the engine, and the four-speed transmission was mounted behind a 22 in (559 mm) flywheel attached to the back of the engine. An open driveshaft connected the transmission to the bevel-drive rear axle. The cockpit was positioned toward the rear of the car. A lever on the outer right side of the car controlled the cable-operated drum brakes on the rear wheels, and a foot pedal actuated a transmission brake. The front wheels had no brakes. Behind the cockpit were tanks for engine oil and fuel, and the car’s body was made of aluminum sheet. The front of the car’s body tapered down but was left open to supply cooling air to the radiator. Exhaust was collected in pipes that ran along both sides of the car and expelled behind the cockpit. A metal underpan attached to the bottom of the frame and helped improve the car’s aerodynamics.
The Sunbeam 350HP had a wheelbase of 10 ft 7 in (3.23 m) and a track of 4 ft 6 in (1.37 m). The car was 3 ft 10 in (1.17 m) tall to the top of the engine cowling and was around 13 ft long (3.96 m). The tires were 34.6 in (880 mm) tall and 4.72 in (120 mm) wide and initially mounted on wooden wheels, but wire wheels were used later. The 350HP weighed approximately 3,417 lb (1,550 kg). The car’s body was finished with a dark green paint covering the nose and tail, and the bare aluminum cowling and cockpit area was polished.
The 350HP made its debut at Brooklands on 19 June 1920 and was driven by Harry Hawker, Sopwith Aviation test pilot and future co-founder of Hawker Aircraft. During a practice session, a front tire blew out, and Hawker lost control of the car. It smashed through some fencing and was not able to compete in the race. The car was repaired and back at Brooklands in August. Again, the 350HP’s potential was not realized when the car stalled, and Hawker was unable to start the race.
The Sunbeam racer was shipped to France where Frenchman René Thomas drove the 350HP in the Gaillon Hill Climb on 10 October 1920. Despite the car being geared for Brooklands, Thomas had better luck in the car than Hawker and set a record by averaging 108.3 mph (174.3 km/h) over the course. This speed broke the old record set in 1912 by German Fritz Erle in the 200 hp (149 kW) Blitzen Benz at 101.7 mph (163.6 km/h).
Hawker made an unsuccessful attempt on the Land Speed Record (LSR) in bad weather at Brooklands on 11 December 1920. He recorded a speed of 124 mph (200 km/h) covering a half mile (.8 km) and 121 mph 195 km/h) covering a mile (1.6 km). Over the next 1.5 years, the 350HP was driven by a number of different drivers and achieved some success at Brooklands, with Kenelm Lee Guinness setting a lap record of 120.4 mph (193.8 km/h) on 28 March 1921. Guinness also covered the Railway Straight half mile stretch at 135 mph (217 km/h) on 24 September 1921.
On 17 May 1922, Guinness and the 350HP set a world LSR at Brooklands, averaging 133.75 mph (215.25 km/h) over the flying km (.6 mi) and 129.17 mph (207.88 km/h) over the flying mile (1.6 km). This was the first LSR for Sunbeam and the last absolute LSR established at Brooklands. The curved track was not able to provide the acceleration distance needed as LSR speeds increased. Guinness also set flying half mile (136.05 mph / 218.96 km/h) and flying two mile (122.11 mph / 196.51 km/h) records. With a substantial amount of wheelspin, Guinness set standing start records covering a half mile in 23.460 seconds (76.73 mph 123.48 km/h), one km in 26.785 seconds (83.51 mph / 134.40 km/h), and one mile in 37.255 seconds (96.63 mph / 155.51 km/h). Guinness continued to campaign the 350 HP throughout 1922 and placed well in various handicapped events.
Like Guinness, Malcolm Campbell was a Brooklands racer and had become interested in setting world LSRs. Campbell was present when the Sunbeam 350HP made its public debut and had seen the car many times at Brooklands. Campbell became infatuated with the 350HP and pushing the record over 150 mph (241 km/h). After some persuasion, Coatalen let Campbell run the car during the speed trials at Saltburn Beach. On 17 June 1922, Campbell recorded six runs along the beach with the fastest timed at 138.08 mph (222.22 km/h), and he averaged 134.07 mph (215.76 km/h) for the flying km (.6 mi). While faster than Guinness, unofficial timing equipment was used, and the speed was not recognized by the Association Internationale des Automobile Clubs Reconnus (AIACR) as a world record. Still, Campbell had proven that the 350HP had more speed available and that he could handle the car. Campbell negotiated with Coatalen and Sunbeam and eventually purchased the 350HP in April 1923.
Once in Campbell’s possession, the 350HP was painted blue, but it retained the polished aluminum cowling. The car was also named Blue Bird, a name applied to all but the earliest of Campbell’s cars. The 350HP was probably the fourth “Blue Bird,” but it was the first LSR car to carry the name—although, it was most often referred to as the 350HP. A few other modifications and repairs to put the car in running order were made by Campbell’s mechanics Leo Villa and Harry Leech.
Campbell’s first run in the 350HP Blue Bird was along the beach on Fanoe (Fanø) Island in Denmark. On 23 June 1923, Campbell recorded a record speed of 136.32 mph (219.39 km/h) over the flying km (.6 mi). On 24 June, Campbell focused on the flying mile (1.6 km) and averaged a record pace of 137.72 mph (221.64 km/h), with 146.40 mph (235.61 km/h) being recorded on the outbound run with the wind. Campbell and the 350HP then participated in a few races at Fanoe and won them all. However, the timing equipment used for the record runs was again not certified by the AIACR, and the records were not accepted.
Campbell knew the 350HP Blue Bird had the speed to set a world record, but he also knew that others were trying to break the existing record. To improve the 350HP’s speed, Campbell turned to Boulton & Paul to improve the car’s aerodynamics through wind tunnel tests. In the first part of 1924, the 350HP’s body was modified with an elongated tail that fit over the existing fuel tank, fairings covering the rear suspension, a streamlined headrest behind the cockpit, a fairing added to the handbrake, and a redesigned scuttle panel just before the cockpit to direct air over the cockpit. The tail added about 3 ft (.91 m), making the car 16 ft (4.88 m) long. The modifications were performed by Jarvis & Sons in South Wimbledon. In addition, new pistons were installed that raised the engine’s compression.
To test the improved 350HP, Campbell ran the car at speed trials along Skegness Beach on 19 June 1924 and at Saltburn Beach on 24 June 1924, where Campbell was unofficially timed at 145.26 mph (233.77 km/h). Everything was ready for the 350HP to make another LSR attempt, but the record was pushed higher before Campbell could try again. On 6 July 1924, René Thomas raised the speed record to 143.312 mph (230.638 km/h) driving a Delage in the speed trials at Arpajon, France. The record was further increased by Ernest Eldridge in the aero-engined FIAT Mephistopheles. Eldridge reached 146.01 mph (234.98 km/h) during an extension of the Arpajon speed trials on 12 July 1924.
Campbell made his next attempt on 24 August 1924 at Fanoe. The state of the beach was far from ideal, and Campbell had complained about a lack of crowd control. Near the completion of the first run, the 350HP’s back tires separated from the rims, but Campbell managed to maintain control. Shaken, Campbell had new tires fitted to the back wheels for the return run. During the run, tragedy struck when the front right tire separated from the rim and stuck a young boy spectator, who subsequently died of his injuries. Campbell was cleared of any wrongdoing, but speed trials were never held again at Fanoe.
Back in Great Britain and at Pendine Sands on 25 September 1924, Campbell and the 350HP Blue Bird made another attempt on the LSR. For this run, the side pipes had been removed, and the engine’s exhaust stacks protruding from the cowling were left bare. In addition, a new wind deflector has been added to the scuttle. On a soggy beach, Campbell averaged a record speed of 146.16 mph (235.22 km/h) over the two runs covering the flying km (.6 mi). This was the fourth time Campbell had recorded a speed in excess of the existing LSR, but it was the first time his speed was recognized by the AIACR. Malcolm Campbell was now officially the world’s fastest man on land.
However, others, like Tommy Milton in the twin-engine Duesenberg, had gone faster during attempts that were not recognized by the AIACR, and Campbell knew his international record would soon be broken. Campbell put the 350HP Blue Bird up for sale and planned to focus on creating a faster car. But he quickly changed his mind after hearing of other LSR contenders, notably John Godfrey Parry-Thomas in Babs. Campbell felt the 350HP Blue Bird had a little more speed left. The 150 mph (241 km/h) mark was tantalizingly close, and he wanted to get there before anyone else.
The 350HP was again modified—the side pipes were reinstalled; the new wind deflector was removed along with the spring fairings; a longer nose was installed with an increased taper that decreased the size of the opening to the radiator; and the cowling was painted blue. The car was tested on 8 June 1925 at Skegness Beach with favorable results. On 21 July 1925 at Pendine Sands, Campbell improved his own record by averaging 150.869 mph (242.800 km/h) over the flying km and 150.766 mph (242.634 km/h) over the flying mile. The km runs were 151.482 mph (243.787 km/h) and 150.261 mph (241.821 km/h), and the mile runs were 152.834 mph (245.962 km/h) and 148.754 mph (239.397 km/h).
Campbell was the first to be internationally recognized for achieving over 150 mph (241 km/h) on land, but he had already set his sights on surpassing 180 mph (290 km/h). Campbell knew the 350HP had reached its limit and had already planned his next LSR car—the Lion-powered Napier-Campbell Blue Bird. In 1925, the 350HP was sold to Ralph Aspden, who sold it to Jack Field in July 1934. The car may have been sold to Bill Cotton in 1936, but it was acquired by G. A. Tuchet-Jesson in June 1941. By this time, a fin had been added to the long tail. In 1944, Harold Pratley purchased the 350HP, which was in a sorry state. The car was cosmetically restored to the Brooklands trim (short tail with green paint) in 1946 by Roots Limited, the company that purchased Sunbeam in 1935.
In 1957, Lord Montagu purchased the Sunbeam 350HP, and it went through an extensive rebuild during 1958–1959. The car was in bad shape, but it was brought back to working order. The original gearbox was gone, but another (although inadequate) transmission had been substituted. The 350HP was put on display in the Montagu / National Motor Museum at Beaulieu and also run under its own power at a few outings. Donald Campbell, Malcolm’s son, drove the 350HP on 14 July 1962 at the Goodwood Circuit.
In 1987, 350HP was rebuilt to Campbell’s 1924 Blue Bird standards. On 2 April 1993, the engine was started for the first time since 1962. A blocked oil passage caused a master rod bearing to overheat, breaking the rod and piston and damaging the crankcase. Starting around 2007, the National Motor Museum worked to restore the engine and car to operating condition. The restoration was completed in January 2014, although the transmission still needs to be replaced, and the museum continues to work toward that goal. The Sunbeam 350HP Blue Bird is on display at the British National Motor Museum and is occasionally run for special events.
This article is part of an ongoing series detailing Absolute Land Speed Record Cars.
– Brooklands Giants by Bill Boddy (2006)
– Sunbeam Aero-Engines by Alec Brew (1998)
– The Land Speed Record 1920-1929 by R. M. Clarke (2000)
– The Record Breakers by Leo Villa (1969)
– The Unobtainable: A Story of Blue by David de Lara (2014)
– My Thirty Years of Speed by Malcolm Campbell (1935)
– Land Speed Record by Cyril Posthumus and David Tremayne (1971/1985)
A lovely read, and gained some knowledge! I have never seen or heard of this before. Thank you!
It would be fair to say that John North at Boulton & Paul attempted to give Campbell a number of aerodynamic options to improve his vehicle’s speed and not all of those revisions were needed in the first instance, enabling the vehicle to be modified as necessary between attempts rather than committing all expenditure at once. B&P Test Engineer A. G. Odgers, reporting in March 1924, first analysed the resistance of the car as used in the 1923 record attempts with a scale model of the car as it existed at that time. He then looked at reduction of resistance by modifying or replacing the model. In each case the overall resistance measured was broken down into components of the car as well to enable each detail change to be quantified. Model No.2 involved an entire redesign of the car based upon recent aircraft tunnel experience but made little difference overall. Model No. 3 was abandoned when it was worse than 1 and 2. The final Model No.4 provided a substantial saving. The tadpole tail and head fairing of No.2 was utilised and it was recommended that exposed chassis frame members were faired. Wheel discs were designed to fit all four wheels but in the interim version only the rear wheels had the discs applied. The 20% reduction in resistance tested suggested a 6.5% increase in top speed was possible, giving the vehicle in excess of 150 mph. The tadpole tail streamlining idea was applied to the rear nacelles of the P.25 Mk.II Bugle, serial J7967 (one of two prototypes ordered February 1924) and to the initial scheme for the P.29 bomber dated April 1924, where attempts at an enclosed radiator fairing below its Lion engines was being tunnel tested in parallel with the Campbell tests. It is quite likely that this front fairing and radiator redesign was similar to that being suggested by Model No. 2.
Archivist – The Boulton Paul Association