Sir Henry "Tim" Birkin began motor racing in 1921, competing in races at Brooklands before family and business pressures forced a temporary retirement. He re-entered racing in 1927 with a three-litre Bentley, initially funding his racing efforts with his own resources, and in 1928 acquired a 4½ litre car, returning to the sport against his family’s wishes. Birkin became one of the “Bentley Boys”, described by W. O. Bentley as “the greatest Briton of his time”. He competed in the 1928 Le Mans race, leading the first twenty laps before a jammed wheel forced him to finish fifth, and won the race in 1929, co-driving the Speed Six with Woolf Barnato.
W. O. Bentley sought a more powerful car, leading to the development of the Speed Six. By 1928, Birkin had come to the same conclusion that the future lay in getting more power from a lighter model, by fitting a supercharger to the 4½ litre Bentley. When Bentley Motors refused to create a supercharged model, Birkin resolved to develop it himself. He established his own engineering works in Welwyn Garden City, Hertfordshire, and secured financial backing from Dorothy Paget, a horse racing enthusiast, after exhausting his own funds. With technical assistance from Clive Gallop and supercharger specialist Amherst Villiers, Birkin began development.
The 4½ Litre Bentley engine featured a single overhead camshaft actuating four valves per cylinder, inclined at 30 degrees—a technically advanced design for the time. The car’s tanks—radiator, oil, and petrol—had filler caps that opened with a single lever stroke, saving time during pit stops. A large Roots-type supercharger was added in front of the radiator, driven straight from the crankshaft, giving the Blower Bentley its distinctive profile and exacerbating understeer. The crankshaft, pistons, and lubrication system were also specifically designed for the Blower engine.
The mechanical modifications increased the engine’s power from 110 bhp (82 kW) in the unblown touring model, to 175 bhp (130 kW) @ 3,500rpm in the blown touring model, and 242 bhp (180 kW) @ 4,200 rpm in the racing model. The Blower Bentley, despite lacking the two additional cylinders of the 6½ Litre, proved more powerful. However, Blower Bentleys consumed 4 litres of fuel per minute at full speed.
The original No.1 had a lightweight Weymann aluminium frame supporting a taut canvas top and a two-seat body. It was officially presented at the British International Motor Show at Olympia, London in 1929. Birkin entered No.1 in the Essex six hour race at Brooklands on 29 June 1929, but the lightweight body caught fire due to a cracked exhaust. The car earned the nickname “Brooklands Battleship”, and Paget funded a re-body with a single aluminium shell by Reid Railton, painted in their racing red colour.
Birkin persuaded W.O. Bentley, with support from company owner and financial backer Barnato, to produce the fifty supercharged cars necessary for the model to be accepted for Le Mans. In addition to the production cars, Birkin assembled a racing team of four remodelled prototypes plus a spare: No.1 (track car with headlights and mudguards), No.2 and No.3 (road registered – GY3904 and GY3905), and No.5 (road registered, assembled from spare parts).
While the naturally aspirated 4½ Litre Bentley was known for its reliability, the supercharged models were generally less so.
Birkin entered No.1 in a 500 miles (800 km) endurance race at Brooklands in 1929, where it caught fire due to a cracked exhaust.
The cars were not ready for Le Mans in 1929, leading to Birkin co-driving the Speed Six. By 1930, only two of the cars started the race. An intense duel between Dudley Benjafield and Birkin’s privately entered Blower Bentleys, and Rudolf Caracciola’s Mercedes SSK, ended with all three cars retiring, leaving the victory to the Bentley works team Speed Six of Barnato and Glen Kidston. Some observers considered Birkin’s courageous and fearless driving, particularly his efforts to push Caracciola, to embody the spirit of vintage racing.
In 1930, Eugène Azemar arranged a Grand Prix race at the Circuit de Morlaas in southern France. The event was initially intended for International Formula cars but was changed to Formula Libre due to a poor response, attracting mostly French competitors. Birkin raced the second road race-prepared supercharged 4.5, registered UR 6571, rather than No.1. Philippe Étancelin won the race in a Bugatti Type 35, with Birkin finishing second, 14 seconds behind, and Zanelli third.
Bentley Motors withdrew from racing in 1930, and was purchased by Rolls-Royce Limited in 1931, which did not authorize racing for a few more years. Dorothy Paget withdrew her support for Birkin’s racing team in October 1930, but continued to support Birkin in No.1. In 1930, the Daily Herald offered a trophy for the fastest driver at Brooklands. Kaye Don won the first year at 137.58 miles per hour (221.41 km/h), but in 1932, Birkin won driving his red Blower Monoposto, clocking 137.96 mph (222.03 km/h). The track record stood for two years, before being beaten by John Cobb driving the 24 litre Napier-Railton.
Birkin continued to operate his motor workshop for two years after Paget’s financial support ended in 1930, partnering with Mike Couper. The partnership specialised in tuning high-performance cars but closed down in 1932. On 7 May 1933, Birkin started the Tripoli Grand Prix in a new 3 L Maserati 8C owned by Bernard Rubin, finishing third. During his pit stop, he burnt his arm badly against the hot exhaust pipe while reaching for a cigarette lighter. There are different opinions of what then happened. The traditional view is that the wound turned septic, whilst others say Birkin suffered from a malaria attack. It was probably a combination of both that proved fatal, and Birkin died at Countess Carnavon Nursing Home, London on 22 June 1933.
Following Birkin’s death and his penniless estate, the family sold most of his assets, including No.1. In the 1970s, the car was acquired by George Daniels, a noted watchmaker and vintage car collector. After Daniels’ death, the car was sold by Bonhams for £5,042,000 at the Goodwood Festival of Speed in June 2012.
A limited run of twelve units of the 1930s Bentley Blower has been produced, built from the original design drawings and tooling jigs used for the four Blowers raced by Sir Henry ‘Tim’ Birkin, including the Team Car (Chassis HB 3403, engine SM 3902, registration UU 5872 – Team Car #2). The Car Zero prototype required 40,000 hours of work.