BR1 is certainly an interesting actor of LMP1 non-Hybrid group with a design that appears quite sophisticated since its first unveiling at Al Sakhir circuit in Bahrain.
This prototype has been design and developed by Dallara for BR Engineering and takes advantage from the design experience gained on the LMP2 car.
LMP1 technical rules, especially on the aero side, provide more room on splitter area that in turn means higher downforce and efficiency with surfaces design that is all but simplified.
Comparing low downforce kit (SPA - Le Mans) with high downforce configuration is always an interesting exercise.
On BR1 the research of lower drag , thanks to less downforce demands, turn into significant shape modification on entire front section of the car.
Front fender has a clear slender shape and extends very close to splitter leading edge. Reduced dimensions of area where positive pressure act ahead of fender is major responsible of downforce reduction. In addition increasing fender’s chord with flatter top surface end ups with lower drag, thanks to minor curvature.
Single dive plate with reduces area, less transverse curvature and extension beyond fender nose claims lower downforce and trimming effect.
BR1- Comparison of low downforce (left) against high downforce configuration. Several differences on front part, nose and fender
All Lmp1 prototypes are creating great level of downforce using front splitter which is practically a front wing in ground effect. Splitter act as main elements and a second element as blow flap complete the front aero device. Slot separating main and flap extends on full span.
Drawing below shows very clearly the front wing operating in ground effect.
(First using this concept was Audi on R15-2009 opening massive discussion about the legality according to the tech rules at that time.)
BR1 - details of front splitter with blown flap configuration
Splitter bottom side reveals the detailed design of this aerodynamics element.
Triangular Vortex Generator located at nearly 50% of main chord to prevent separation.
Longitudinal Fences facing the front wheel to guide the flow an blow it where is desired rather than leave it free to develop in an uncontrolled high vorticity zone in this very sensitive area facing the rotating wheel.
BR1 – detailed view of front splitter bottom side. Vortex generators
BR1 – Longitudinal Fences facing the front wheel
Turning vanes under noose, are also components well developed on BR1. Those elements are design to direct the flow coming from splitter trailing edge, diverging it alongside improving underflow pattern and feeding rear diffuser with cleaner airflow.
BR1 – Complex turning vanes system to guide flow coming from front splitter
Detailed view of the three vertical turning vanes in the front-side area of side pod. This channel, between inside fender cusp and tunnel intake need to guide the flow around the high velocity low pressure surface of side pod, reducing drag and avoid separation.
Vertical span of the second and third vanes are so to create a tapered equivalent surface with less wetted area and blocking effect.
BR1 – barge boards on sidepod at tunnel entry