BAT Cars

[sgtlethargic]

A thread dedicated to discussing the interesting aerodynamic strategies of the Alfa Romeo BAT cars.

italiaspeed.com

[sgtlethargic]

The design of the BAT 7 prototype was based on a study of aerodynamics. The shape of the front aimed to eliminate the problem of airflow disruption at high speeds. The design also aimed to do away with any extra resistance generated by the 16” wheels when revolving. This was achieved by the intriguing tiramaran nose, which channelled air into the inlets and extracted it behind the front wheels. The nose design also resulted in a structure which reduced the amount of air vortexes.

Other aerodynamic details included the impressive tumble-home on the side windows, which were angled approximately 45° to the vertical, and a large windscreen which blended in perfectly with the almost flat roof.

The most surprising aspect of the design was the tail, with an extended rear window divided by a slim pillar; the whole affair being flanked either side by two elegant fins which tapered upwards and inwards. Flow patterns were shaped by these rear fins, which each included a small slot for pressure relief.

In practise, these rigorous criteria resulted in an astonishing Cd value 0f 0.19.

According to this website the CD is 0.19.

[freebeard]

This was achieved by the intriguing tiramaran nose, which channelled air into the inlets and extracted it behind the front wheels.

I did not know that. It may be the earliest example of this. Contemporary cars like the Aston Martin Valkyrie and the new Bugatti concept carry it on.

I think the slots in the fins are for crosswinds.


justacarguy.blogspot.com: Alfa Romeo BAT #5 by Bertone,1953.

In this view you can see the windshield has a reflex curve in the lower corners, Similar to the back window of the fourth generation Camaros.

[sgtlethargic]

Trimaran?

A trimaran (or double-outrigger) is a multihull boat that comprises a main hull and two smaller outrigger hulls (or "floats") which are attached to the main hull with lateral beams.

[sgtlethargic]

The shape of the front aimed to eliminate the problem of airflow disruption at high speeds.

I'm not concerned with high speeds (the same article says its top speed with a certain engine was ~125 mph).

Anything of interest with regard to airflow disruption and the front shape?

[kach22i]

Originally Posted by sgtlethargic

A thread dedicated to discussing the interesting aerodynamic strategies of the Alfa Romeo BAT cars.

italiaspeed.com

Nice find.

[jjackstone]

These cars just sold at auction last week.

https://www.classicdriver.com/en/art...rs-148-million

JJ

[aerohead]

Originally Posted by sgtlethargic

I'm not concerned with high speeds (the same article says its top speed with a certain engine was ~125 mph).

Anything of interest with regard to airflow disruption and the front shape?

A-Pillar vortices would be of interest.