Profiles and Logos
Sir Henry “Tim” Birkin, described as “the greatest British driver of his day” by W.O. Bentley, was one of the Bentley Boys. He refused to adhere strictly to Bentley’s assertion that increasing displacement is always preferable to forced induction. Birkin, aided by a former Bentley mechanic, decided to produce a series of five supercharged models for the competition at the 24 Hours of Le Mans, it’s rival Mercedes-Benz had been using superchargers for years.
The essential difference between the Bentley 4½ Litre and the Blower was the addition of a Roots-type supercharger to the Blower engine by engineer Amherst Villiers, who had also produced the supercharger. W.O. Bentley, as chief engineer of the company he had founded, refused to allow the engine to be modified to incorporate the supercharger. As a result, the supercharger was placed at the end of the crankshaft, in front of the radiator. This gave the Blower Bentley an easily recognisable appearance and also increased the car’s understeer due to the additional weight at the front. Thus the 4½ litre Blower Bentley was born. The first supercharged Bentley had been a 3-litre FR5189 which had been supercharged at the Cricklewood factory in the winter of 1926/7. The Bentley Blower No.1 was officially presented in 1929 at the British International Motor Show at Olympia, London. The 55 copies were built to comply with 24 Hours of Le Mans regulations. Birkin arranged for the construction of the supercharged cars having received approval from Bentley chairman and majority shareholder Woolf Barnato and financing from wealthy horse racing enthusiast Dorothy Paget. Development and construction of the supercharged Bentleys was done in a workshop in Welwyn Garden City by Amherst Villiers, who also provided the superchargers.
A total of 720 4½ Litre cars were produced between 1927 and 1931, including 55 cars with a supercharged engine popularly known as the Blower Bentley. A 4½ Litre Bentley won the 24 Hours of Le Mans in 1928.
Though the supercharged 4½ Litre Bentley’s competitive performance was not outstanding, it set several speed records, most famously the Bentley Blower No.1 Monoposto in 1932 at Brooklands with a recorded speed of 222.03 km/h (138 mph).