Le Mans 24h qualifying sessions clearly confirm the performances level noted since collective practice sessions at Paul Ricard and first event of WEC super Season 2018/2019 at Spa Francorchamps circuit.
Reference car is undoubtedly Toyota TS50 that could be considered almost without competitors on Lmp1 class, thanks to long participation to WEC and available resources, significantly larger than all other teams.
Fortunately reliability is still to be verified for all competitors, this will be key factor since winners at Le Mans were not always the fastest cars.
We are only few hours ahead from getting answers to several considerations made by enthusiasts during last months.
Meanwhile we quickly review here some interesting configuration seen on all other Lmp1: BR01, Ginetta G60, Ligier JSP217.
Looking at front part of BR 01 Lmp1 is easy to notice all aspects that are forming Le Mans kit. Front nose is designed with less downforce target to the benefit of lower total drag.
Top speed on very long straights is key factor to obtain fast lap time, while keeping an acceptable level of downforce makes better cornering performance and easier and safer handling during braking and line changes.
Front fenders are longer, longitudinally extended with nose that seats closely to splitter leading edge. This reduces the area on splitter top surface where high pressure insist, reducing therefore downforce. Longer chord of the fender make it slender and finer with less curvature on top surface. The concave surface ahead of the mandatory vent on fender is also less evident.
There is a single “Dive plate” with smaller area, less transverse curvature, shorter extension ahead of the fender nose and is collocated vertically with closer gap from the splitter.
Nose-fender blending is at full width and brake air intake shows larger duct section to increase cooling.
BR01 – Comparison of low downforce configuration (left) and high downforce. Significant differences on front nose, and fender.
As known Rebellion R13 is designed around Oreca 07 Lmp2 chassis and Gibson GL458 engine.
Nevertheess there are several original concepts on R13 Lmp1 aero configuration. Front keel under nose and turning vanes are more sophisticated in ths area that serves to “clean” flow from the splitter guiding it at rear side of front wheel. Wheel drum around hub and brake disk enable a better controls of vorticity of inner and outer area of wheel rim, improving also brakes cooling efficiency.
Ahead of rear wheel arc, there are 3 vortex generator, located inside an hollow surface, that marks a flat area in front of tyre, guiding the flow around it.
Comparison Rebellion R13 Lmp1 (left) vs. Oreca 07 Lmp2 – Turning vanes between keel and wheel with hub drum around brake disk. Details of hollow surface with vortex generators ahead of rear wheel
Ginetta G60-LT-P1 has an under nose concave surface that extends at full width between front fender. This shape is optimised to handle upwash flow generated by front splitter and feeding centre part of keel and underbody.
Design of under nose has important consequences on aero “blocking effect” and front ride height sensitivity, that’s why is a key factor of front nose aero concept.
Turning vanes shapes are really original, with smaller lateral surface and less curvature than all other Lmp1 cars. To be noted also the top edge of centre elements (red coloured) deeply cutted so that only the lower edge is acting on the flow under the splitter.
Ginetta G60-LT-P1 view of under nose with turning vanes
Ligier JSP217 front assembly is clearly different with the Le Mans aero kit.
Reduced downforce target claims modifications on spanwise shape of the splitter: shorter chord and reduces curvature. As we mentioned already front splitter is as wing working on ground effect and those modification increase efficiency.
Due to less airflow desired on top of the splitter there is a larger surface bridging nose and fender inside part that is extender further forward resulting in a small gap over the splitter, integrating bigger air duct to cool front brakes.
Ligier JSP217 – different nose configurations: with larger chords at splitter side edge (left), compared to low downforce kit for Le Mans (right)