DB1 / Lazer skirt

[jstoezel]

H,

What is the purpose of the flared-out skirt at the bottom of the bodywork of DB1 and the FV Lazer?
Is it to guide the air for cooling (NACA on DB1, heads openings on Lazer), is it there for some kind of down force effect (less likely I guess), other?







Thanks,
Jean

[Neil_Roberts]

It's a downforce thing, but not a big one. The flared perimeter adds floor area and produces a stronger vortex if the floor is nose down relative to the pavement. The nose down attitude creates lower pressure under the car, producing some downforce. Nature abhors a vacuum, so air gets pulled in from every possible place to fill that vacuum.

The DB-1 was designed with the flywheel 1" below the floor, so there is 1" of rake designed in. Unfortunately, the center of pressure was too far forward, which promoted oversteer in fast corners.

[Brad Smith]

Plus, it looks cool. Just bought your book, Neil and it looks good.

[jstoezel]

Hi Neil:

Thanks for the reply. I thought no aerodynamics were allowed in both of these classes.

Would the characteristics of both cars be modified if say, the bottom of the cockpit area was to protude on each side (not inline with the rest of the bodywork)?
What happens when the belly diverges from the centre line around the front roll hoop? Similarly, what happens when the belly pan converges back towards the centre line of the car in the engine bay area?


Jean

Originally Posted by Neil_Roberts

It's a downforce thing, but not a big one. The flared perimeter adds floor area and produces a stronger vortex if the floor is nose down relative to the pavement. The nose down attitude creates lower pressure under the car, producing some downforce. Nature abhors a vacuum, so air gets pulled in from every possible place to fill that vacuum.

The DB-1 was designed with the flywheel 1" below the floor, so there is 1" of rake designed in. Unfortunately, the center of pressure was too far forward, which promoted oversteer in fast corners.