ForumA record in the Volkswagen wind tunnel
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A record in the Volkswagen wind tunnel
by Grizzly Mon Apr 01 2013, 12:50
Volkswagen special version of 1947 measures a drag coefficient (Cd) of just 0.217 by Pete Frost
Tests of the vintage Volkswagen in the Wolfsburg climatic wind tunnel yielded a surprisingly low drag coefficient
Aerodynamic fine-tuning is an important factor in reducing drag. Volkswagen engineers realised this even during the early years of the company in the 1940s. A special version of the Beetle from 1947 has now been measured in Volkswagen’s climatic wind tunnel at Wolfsburg and the low drag coefficient has been a surprise.
A streamlined vehicle design helps - and this is particularly important today - in the reduction of CO2 emissions. The new Golf is a good example of streamlining and has a drag coefficient (Cd) of only 0.27 with a frontal area of 2.19 square metres. In comparison, the familiar rounded shape of the original Beetle several decades earlier, even in standard trim, had a drag coefficient of 0.46 with a frontal area of 1.80 square meters which was impressive for its time.
Now an aerodynamically optimised special version of the original Beetle from 66 years ago has been studied in one of the most unusual wind tunnel tests conducted by Volkswagen. The results were to astound the Wolfsburg engineers.
Streamlined details go back to fundamental studies by Baron von König-Fachsenfeld
The Volkswagen special “V2 Sagitta” was built in 1947 by Kurt Volkhart. In the early 1940s, Volkhart had begun to develop a streamlined sports version of the Beetle based on fundamental studies of the legendary aerodynamicist Baron von König-Fachsenfeld. One prototype featured a continuous dorsal fin, but only his Sagitta project was finally completed. With a lightweight aluminium body on a tubular steel trellis frame, it featured a Volkswagen flat-four air-cooled 1.1-litre boxer engine producing 24.5 hp. Thanks to the streamlined profile similar to that of the body of the Porsche 356, a respectable 140 km/h (87 mph) was possible.
A serious technical examination in the wind tunnel of the V2 Sagitta was conducted in January 2013. The car was long believed to have been lost, but it recently came to light when it made an appearance at a Concours d'Elegance. The technical team led by Dr. Alexander Wittmaier of Volkswagen Research & Development arranged for the vehicle to be transported from its present location in Austria to Wolfsburg for aerodynamic evaluation in the wind tunnel. Besides the Volkswagen brand in the Volkswagen Group, Audi and Porsche also have well-appointed wind tunnels.
The drag coefficient deteriorated when the wheel arch covers were removed
The two most important factors for assessing the aerodynamics of a vehicle are the frontal area and drag/resistance. The smaller the coefficient of drag, the more slippery the vehicle. Both values can be determined with appropriate preparatory work within a relatively short time. During wind tunnel tests, the V2 Sagitta measured a drag coefficient of just 0.217 with a frontal area of 2.10 square metres. These are excellent values when you consider that they have only just been undercut by the recently launched production version of the streamlined Volkswagen ‘Super Efficient Vehicle’ XL1 which was tested in the Wolfsburg wind tunnel at a drag coefficient of 0.189 with a frontal area of 1.50 square metres.
Whilst testing the V2 Sagitta, the aerodynamic effectiveness of individual components such as the wheel arch covers were investigated. When the covers were removed, the drag coefficient deteriorated to 0.252. Conversely, with the wipers removed or using a small rear wing, the drag coefficient was further reduced to 0.216.
The V2 Sagitta of 1947 is unique and this is a rare outing on public roads. 66 years later, Volkswagen has launched the
XL1 streamlined plug-in hybrid Super Efficient Vehicle (below) with a remarkably similar drag coefficient to its aerodynamic predecessor.
Tests of the vintage Volkswagen in the Wolfsburg climatic wind tunnel yielded a surprisingly low drag coefficient
Aerodynamic fine-tuning is an important factor in reducing drag. Volkswagen engineers realised this even during the early years of the company in the 1940s. A special version of the Beetle from 1947 has now been measured in Volkswagen’s climatic wind tunnel at Wolfsburg and the low drag coefficient has been a surprise.
A streamlined vehicle design helps - and this is particularly important today - in the reduction of CO2 emissions. The new Golf is a good example of streamlining and has a drag coefficient (Cd) of only 0.27 with a frontal area of 2.19 square metres. In comparison, the familiar rounded shape of the original Beetle several decades earlier, even in standard trim, had a drag coefficient of 0.46 with a frontal area of 1.80 square meters which was impressive for its time.
Now an aerodynamically optimised special version of the original Beetle from 66 years ago has been studied in one of the most unusual wind tunnel tests conducted by Volkswagen. The results were to astound the Wolfsburg engineers.
Streamlined details go back to fundamental studies by Baron von König-Fachsenfeld
The Volkswagen special “V2 Sagitta” was built in 1947 by Kurt Volkhart. In the early 1940s, Volkhart had begun to develop a streamlined sports version of the Beetle based on fundamental studies of the legendary aerodynamicist Baron von König-Fachsenfeld. One prototype featured a continuous dorsal fin, but only his Sagitta project was finally completed. With a lightweight aluminium body on a tubular steel trellis frame, it featured a Volkswagen flat-four air-cooled 1.1-litre boxer engine producing 24.5 hp. Thanks to the streamlined profile similar to that of the body of the Porsche 356, a respectable 140 km/h (87 mph) was possible.
A serious technical examination in the wind tunnel of the V2 Sagitta was conducted in January 2013. The car was long believed to have been lost, but it recently came to light when it made an appearance at a Concours d'Elegance. The technical team led by Dr. Alexander Wittmaier of Volkswagen Research & Development arranged for the vehicle to be transported from its present location in Austria to Wolfsburg for aerodynamic evaluation in the wind tunnel. Besides the Volkswagen brand in the Volkswagen Group, Audi and Porsche also have well-appointed wind tunnels.
The drag coefficient deteriorated when the wheel arch covers were removed
The two most important factors for assessing the aerodynamics of a vehicle are the frontal area and drag/resistance. The smaller the coefficient of drag, the more slippery the vehicle. Both values can be determined with appropriate preparatory work within a relatively short time. During wind tunnel tests, the V2 Sagitta measured a drag coefficient of just 0.217 with a frontal area of 2.10 square metres. These are excellent values when you consider that they have only just been undercut by the recently launched production version of the streamlined Volkswagen ‘Super Efficient Vehicle’ XL1 which was tested in the Wolfsburg wind tunnel at a drag coefficient of 0.189 with a frontal area of 1.50 square metres.
Whilst testing the V2 Sagitta, the aerodynamic effectiveness of individual components such as the wheel arch covers were investigated. When the covers were removed, the drag coefficient deteriorated to 0.252. Conversely, with the wipers removed or using a small rear wing, the drag coefficient was further reduced to 0.216.
The V2 Sagitta of 1947 is unique and this is a rare outing on public roads. 66 years later, Volkswagen has launched the
XL1 streamlined plug-in hybrid Super Efficient Vehicle (below) with a remarkably similar drag coefficient to its aerodynamic predecessor.
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