Guide: Alfa Romeo BAT
Background
Although other eras have produced their fair share of spectacular automotive designs, the early 1950s was a particularly renowned period for amazing four-wheeled creations.
The rapid technological progress brought about as a result of World War 2 led to the dramatic arrival of jet age styling. Another influence was a widespread fascination with science fiction that resulted in an influx of other worldly futurism.
Before World War 2, Alfa Romeo had produced a number of streamlined models, the most famous of which were a series of 8Cs that wore cutting edge designs by Carrozzeria Touring of Milan.
When Alfa Romeo disbanded their Formula 1 programme at the end of 1951 (having won back-to-back championships with the 158 / 159), attention was switched to a sports car campaign with an experimental machine tenuously based on the forthcoming 1900 road car. The resultant C52 (frequently dubbed the Disco Volante) was a collaboration between Alfa Romeo’s competition department, the firm’s chief designer, Gioacchino Colombo, and Touring of Milan. However, the C52’s revolutionary styling was found to cause significant lift and the car never actually raced in its original form.
While Alfa Romeo did subsequently go sports car racing with the more effective 6C 3000 CM, the exploration of pioneering automotive aerodynamics was switched to a series of show cars where the pressure of competition would not be a consideration.
After the Touring-designed C52 had proven a disappointment, Alfa Romeo decided to collaborate with Carrozzeria Bertone instead. An exciting project dubbed Berlina Aerodinamica Tecnica (BAT) was given the go-ahead.
Alfa Romeo commissioned Bertone to begin the programme in the autumn of 1952. The BAT cars that emerged would be designed to minimise drag and provide the smoothest possible air penetration.
As the Alfa Romeo BAT cars would be technical as much as styling studies, Nuccio Bertone commissioned Franco Scaglione as head designer. Scaglione was renowned for his interest in science and mathematics and therefore represented the ideal candidate.
Chassis
Alfa Romeo chose to use their 1900 model as the basis for the BAT cars.
Introduced at the Paris Motor Show in October 1950, the 1900 was the first Alfa Romeo built without a separate chassis and was designed to easily accept bodywork from different coachbuilders.
The original 1900 used a pressed steel unitary chassis with a 2630mm wheelbase. In 1951, the 1900C with its shorter 2500mm wheelbase was added to the range.
Independent double wishbone suspension was fitted at the front. A live rear axle with radius arms and a triangular lateral locator was installed at the back. Coil springs and telescopic shock absorbers were fitted all round along with drum brakes. Solid steel and spoked Borrani wire wheels were both used.
Engine & Gearbox
Alfa Romeo developed a new Tipo 1306 dual overhead camshaft inline four cylinder engine for the 1900. It featured a cast-iron block, an aluminium alloy head and displaced 1884cc thanks to a bore and stroke of 82.55mm and 88mm respectively.
With a 7.5:1 compression ratio and single Weber or Solex carburettor, peak output was 90bhp at 5200rpm. The more powerful 1900 TI (Turismo Internazionale) came with bigger valves, a higher 8.0:1 compression ratio and dual carburettors. It produced 100bhp at 5500rpm.
In 1953, a Tipo 1308 variant bored to 84.5mm for a displacement of 1975cc was added to the range. Offered in the 1900 Super and TI Super, it came with dual Solex carburettors and pumped out 115bhp at 5500rpm.
Both four and five-speed gearboxes were variously supplied.
BAT 5
The first of Scaglione’s BAT cars was BAT 5, the styling of which was clearly influenced by an earlier commission from Carlo Abarth. Abarth wanted a state-of-the-art styling exercise to help publicise his company and the avant garde 1500 Biposto displayed at the Turin Motor Show in April 1952 did not disappoint.
BAT 5 derived its ‘5’ moniker as Scaglione initially created four full-size models prior to the final car. It was built on chassis AR1900.01396 and was readied to appear at the 1953 Turin Motor Show which opened in late April.
Aerodynamics accounted for 85% of the car’s form; Scaglione wanted to minimise airflow disruption at high speed and create the fewest possible vortices.
The front end featured pontoon fenders with inboard retractable headlights. A rounded central nose ducted airflow over the swept hood and into large intake nostrils with horizontal vanes. The engine was modified with sidedraught carburettors to allow for the lowest possible profile.
Down each flank, the wheels were enclosed to reduce resistance. Large vents were added to cool the front brakes along with small vertical ducts for those at the rear.
The teardrop cabin incorporated large wraparound screens at either end while the side glass was angled at around 45°. The enormous rear windows were divided by a slim pillar which merged into a central spine that stabilised airflow. Dramatic rear fins on either side tapered upwards and inwards.
BAT 5 was painted grey with red grilles, red upholstery and grey carpet.
The two-seat cockpit was equipped with a single piece wraparound dash that housed all the instrumentation within an unusual five-gauge binnacle. Bucket seats were trimmed with ribbed centres to match the lower door panels and rear sidewalls. Behind the seats was a carpeted luggage platform.
BAT 5 had an extraordinarily low drag coefficient of 0.23 and a quoted top speed of 123mph. It drew a massive amount of press coverage and convinced Alfa Romeo to commission two further BAT cars.
BAT 5 was sold to Bertone Director and shareholder, Stanley Arnolt.
BAT 7
Scaglione was instructed to take an even more extreme approach for the second BAT car of the series: BAT 7.
Built on a short wheelbase 1900C (chassis AR1900C.01485), BAT 7 was commissioned for the 1954 Turin Motor Show which opened in late April.
Encouraged to emphasise various characteristics of the original and target an even lower drag coefficient, Scaglione made a series of subtle modifications. The central nose element was extended and the intake nostrils on either side were made shallower to allow for a lower profile hood. Scaglione also ditched BAT 5’s inboard retractable headlights. They were replaced with spot lights either side of the central nose element that swung downwards when in use.
For BAT 7, the original side profile was cleaned up; it featured fully faired-in cooling vents for the front brakes and larger intake scoops for those at the rear. Meanwhile, instead of exiting underneath the car (as had been the case with BAT 5), BAT 7 had its exhausts fully shrouded into the sides of the rear bodywork.
BAT 7’s teardrop cabin was extended rearwards, given more of a fastback profile and an even more pronounced central spine. Re-shaped windows had softer contours than before. Longer, taller and more steeply raked tail fins came with more aggressive curvature at the trailing edge and larger angled cut outs.
As a result of these changes, the drag coefficient dropped from 0.23 to an astonishing 0.19.
Scaglione opted for a metallic blue exterior with a two-tone black and white cockpit.
Whereas BAT 5 had been left-hand drive, BAT 7 was right-hand drive. Buckets were switched to conventional well-padded seats upholstered with black leather faces, white piping and white squabs. White leather was also used for the door panels, transmission tunnel and sidewalls. The unusual triangular instrument binnacle from BAT 5 was subtly reworked so as to accommodate three gauges instead of five.
BAT 7 was finished so late that Franco Scaglione and Nuccio Bertone had to drive it to the 1954 Turin Motor Show themselves. As per BAT 5, this latest creation was sold to Stanley Arnolt.
BAT 9
With little chance of significantly improving BAT 7’s extraordinary aerodynamic efficiency, Alfa Romeo decided to take a slightly different approach for the last car in the series: BAT 9.
The mandate was for something that more closely resembled a production car which meant practicality and visibility also now became considerations. BAT 9 (sometimes referred to as BAT 9d) was built on chassis AR1900.01600. It was commissioned for the 1955 Turin Motor Show which again opened in late April.
The nose was reprofiled to accommodate the grille from an Alfa Romeo Giulietta either side of which were the slimmest intake nostrils yet seen. Pontoon fenders housed fixed headlights under contoured glass covers and vertical bumperettes were also fitted.
More bulbous flanks meant there was now sufficient space to apply full lock on the partially enclosed front wheels. The spats at the back were removed completely and only the tops of the rear wheels were enclosed. A bulging swage line became significantly more pronounced towards the hind quarters.
BAT 7’s teardrop cabin, split rear window and stabilising spine were largely retained for BAT 9, but the rear fins were reduced in size and given a less dramatic upward profile. The rear apron was completely new. It now contained a licence plate housing that doubled up to channel airflow underneath the car. Unlike BAT 7, BAT 9’s exhausts system reverted to a conventional exit pattern underneath the tail.
Inside, six gauges were housed in an oval binnacle and the remaining switchgear was located off towards the centre. BAT 9 had easily the most inviting ambience of the three BAT cars with its plush seats and elegant tan upholstery. Like BAT 5, BAT 9 was left-hand drive. The exterior was originally painted two-tone silver on black.
BAT 9 was also sold to Stanley Arnolt.
Thanks in part to the success of the BAT project, Alfa Romeo handed Bertone a production contract for the Giulietta Sprint which safeguarded the coachbuilder’s future.
Text copyright: Supercar Nostalgia
Photo copyright: Bertone - https://www.bertone.it & RM Sotheby’s - https://rmsothebys.com/
