On target
In last month’s issue, Le Mans Hypercar (LMH) class regulations were reviewed, highlighting what, in the author’s view, are the most significant points. Rules related to performance-critical areas like powertrain, aerodynamics and tyres will be analysed in more detail here to understand how the rulebook should lead to cars achieving the targeted lap times of 3m30sec in Le Mans race trim.
In this instalment, we will perform an in-depth analysis using lap time simulation to quantify and understand how LMH cars are expected to perform.
The tool employed for this investigation was coded by the author and is based on a quasi-static approach; each small section of a track is analysed assuming a constant acceleration and that the vehicle is in static conditions. The four-wheel vehicle model incorporates full aeromaps, suspension kinematics, corner and heave springs, bump stops for each axle and anti-roll bars.
The powertrain model inputs include a torque curve, gearbox efficiency, gear ratios, the portion of driving torque applied to each axle and shift time.
The tyre model is similar in structure to a Pacejka one, but with each effect modelled separately, including those of load, slip, camber and vertical characteristics (stiffness and expansion with speed).
Simulation output results include more than 100 channels, covering all areas of the car. The correlation against real world is good, despite the simplified approach, and the author feels it can be used with confidence for both predictive analysis and general studies.
Pre-study calibration
Before modelling a representative LMH car, some simulations have been run in Le Mans with an LMP2 vehicle model, in 2020 specification. The goal of this
