1999-2000 BMW LMR

Images courtesy and copyright Chris Abele and BMW AG
Text and images copyright Michael J. Fuller

The 1999 rear wing specification.  BMW bucked the trend and opted to run the wing more as a traditional underbody extractor than as a true wing in its own right.  Typically this is considered a Le Mans low downforce trend.  But BMW showed up at all the circuits in '99 running this same basic configuration.
A close up of the 1999 BMW rear wing endplate.  Here we can see the very diminutive gurney at the top of the secondary element.  The endplates are also of a very different shape. The endplate shape was designed to add energizing airflow near the slot gap of the secondary element, though it is probably most effective while the car is yawing into a corner as opposed to straight line running.
In 2000 the ACO changed the rules governing rear wing endplates in response to the Mercedes CLR flips at Le Mans the year before.  The ACO wanted to mandate with in the rules a aero. balance shift forward.   The ACO thought that by reducing rear downforce (limiting the rear wing endplate size) and increasing front downforce (mandating louvres in the front wheel arches) aerial flips like the Mercedes' would be less of a possibility.  For 2000 and beyond rear wing endplates were limited, "To a volume measuring 40 cm horizontally x 15 cm vertically".  BMW had to scrap the previous season's endplate and design a new shape with in the new rules.  It is clear that the endplate theory established on the '99 LMR has carried over.  The dished out section towards the trailing edge works to add energy to the slot gap. 

©Copyright 2001, Michael J. Fuller