Getting it done in lockdown…Bentley scans legendary 1929 Bentley ‘Blower’

1929 Bentley Blower

Last year, Bentley announced it would release a handful of recreated 1929 ‘Blower’ Bentleys, and the engineers have finished scanning the thing in isolation.

Bentley has finished the digital scan needed to produce 12 new Bentley Blowers, each one will be an exact copy of the ones raced by Sir Tim Birkin. Before we go on, if you’ve started rummaging around underneath your couch cushions, don’t bother, all 12 have already been purchased.

The Continuation cars are being produced by a team in Bentley Mulliner’s Classic division, who are working with a team of vintage specialists to re-engineer and build the parts needed to bring the new series of cars to life.

How was it done? “Bentley’s Team Blower has been carefully dismantled and then re-created in the digital world through a combination of precision laser-scanning and intricate hand measurement. The finished CAD model is comprised of 630 components across 70 assemblies, and is more than 2GB in size,” Bentley said.

From start to finish it’s taken 1200 man-hours for two CAD engineers to complete the model from the scan data and measurements. The engineers have been able to complete the model while working remotely during the COVID-19 crisis.

1929 Bentley Blower being scanned

The Bentley Blower is undoubtedly the most famous Bentley of all time, yet only four Team Blowers were originally built for racing by Birkin. Indeed, Birkin’s own car No.2 is the one being used by Bentley to scan and reproduce the continuation cars. Bentley’s original Team Car will then be reassembled, with the heritage team taking the opportunity to complete a detailed inspection with a sympathetic and conservative mechanical restoration where required to return the car to its original 1929 specification. 

As continuations of the original Team Blower, each of the new Continuation Series cars will feature four-cylinder, 16-valve engines with an aluminium crankcase with cast iron cylinder liners and non-detachable cast-iron cylinder head. The supercharger will be an exact replica of the Amherst Villiers Mk IV roots-type supercharger, helping the 4398cc engine to develop 240bhp at 4200rpm. The car’s structure will be a pressed steel frame, with half-elliptic leaf spring suspension with copies of Bentley & Draper dampers. Recreations of Bentley-Perrot 40cm (17.75-inch) mechanical drum brakes and worm and sector steering complete the chassis.

Interestingly, the Bentley 4½ Litre was nearing the end of its development cycle by 1928, with other car makers catching up. W.O.’s response was to increase the engine capacity, and his 6½ Litre model won Le Mans in 1929 and 1930.

However, racing driver Sir Henry Birkin, had another idea. He wanted to fit an innovative new supercharger to the engine of the existing 4½ Litre car instead. To W.O.’s displeasure, Birkin persuaded Bentley’s new owner and chairman, fellow Bentley Boy and British financier, Woolf Barnato, to build him five supercharged Blowers for the racetrack. And to meet the racing rules of the era, 50 production Blower Bentleys were built for the road too.

Birkin and the Blower are intrinsically linked together. Indeed, it was Birkin’s quest for speed that created the Blower, later recording heroic drives at the Le Mans 24 Hours and the French Grand Prix. He also broke the Brooklands outer-circuit lap record, the most coveted racing circuit of the time.

The Blower’s finest hour was in the 1930 French Grand Prix at Pau when, amid a field of lighter Bugattis, Birkin drove his Blower to a second place podium finish. The Blower is still believed to be the heaviest car ever entered in a Grand Prix. Another version of the Blower was later converted into a single-seater and raced on the banked circuit at Brooklands in Surrey. With the engine output increased to 240 bhp, Birkin achieved 222 km/h (137.9 mph) when breaking the Brooklands lap record, his car often airborne due to the poor quality of the surface.

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Isaac Bober has been writing about cars and 4x4s for more than 20 years, has worked on some of the country's biggest motoring magazines (remember what they were?), and launched Practical Motoring. Now he's back, back again... to share dad jokes and much more.