WecTech, inside the Isotta Fraschini Tipo 6 LMHC.

It is a real pleasure to see Isotta Fraschini challenge to Hypercars class, the pinnacle of Endurance racing.

This program has been announced on December 2022.  Design and engineering works has been done by Michelotto Automobili that has top pedigree and history on Endurance race cars.  Hybrid powertrain is developed by HWA.

Thermal engine is 3 liters V6 90° with single turbocharger.   Electrical section with battery is designed by Williams Advanced Engineering. Hybrid powertrain software management is realized by Bosch.  Gearbox and differential are made by Xtrac.

Tipo 6 LMHC front view show the general aero concept adopted for this car.   Front splitter has a linear leading edge raised on central part, just inside the front fender footprint.

Downforce generation is demanded to a single element with extended chord that is designed to work in ground effect and guide the airflow from trailing edge to the bottom part of the nose.

Interesting to note than the suction side of undernose fairing is descendent vertically in a sort of concave shape.

Front fender has “rectangular” front shape with almost flat surface on the top and bulge leading edge.

We know this trend of front fender design has been introduced and developed at the type of LMP1 class, with the attempt to reduce lift generation creating a flow structure that is passing along the vertical sides of the fender rather than on a convex top surface.

Two triangular dive plates are collocated on external side of the fenders as typical element to fine tuning the longitudinal aero balance.

Small Gurney flaps at trailing edge of the splitter, at the extremities of it span are used to trim the downforce/drag ratio.

Tipo 6 LMHC – Front aero concept with single element splitter, fender’s bulge nose, dive plates and nolders.

Side view illustrates how canopy and roof centreline are gently profiled, without typical flat portion seen on other Hypercars.  This means that entire top body shape is designed to works with a 3D flow shape rather than central portion optimized to promote flow along the sides, with the attempt to reduce lift and intense pressure gradient at windshield-roof intersection.

Rear fender leading edge is collocated quite far upstream, permitting a very narrow portion of the volume ahead of the rear wheels.  Airscope vertical extension is significant, permitting to intercept clean air free of boundary layer developed over the top of the car.

Comparing the rear portion profile with the overall lines the volume dedicated to the scope and inside tunnel is evident.

Tipo 6 LMHC  – Side view, front and rear fenders shape, top canopy profile and intake airscope.

Very nice outlook of the front part is offered by this drawing.   Concave and downward direction of nose bottom surface is quite evident, especially on the centre portion of splitter, inside the vertical pillars that hold it structurally.

Then there is a twist with less attack angle moving along the span.   Airflow leaving the splitter trailing edge is guided to feed the underbody floor.   We can note that splitter side portion shows chord distribution and twist typically seen on a secondary element, like flap.  In this case we have a single element without any slot.

During the development this area has been subjected to refinement, surely dictated by aeromap resulted from full scale measurements on wind tunnel.  The channel between splitter suction side and ground is constant along the entire splitter.

Tipo 6 LMHC – details of nose underbody, splitter and vertical pillars.

Front fender cone and trailing edge has been modified after the first shake down at Monza.   Yellow part outlined in the drawing is an extra volume that has been added backside of the maximum fender width, shaped so to extend and collocate closer to side pod entry the inner surface of this channel.  Flow structure behind front fender is very important as it interferes directly with the wake created by the car.

The wake has to be guided along the sides without feeding the underbody channel with low energy flow that will reduce downforce generation.   This is another example of aerodynamics “closed loop development”, feed by Cfd analysis verified with wind tunnel results.

The scope is to fall inside the permitted area on the -Cl/Cd map that is one of the key aspects that Hypercar rules mandate with the aims of levelling cars performances.

Tipo 6 LMHC – Shape development on rear cone and trailing edge of front fender.

Details of rear mirror shape with main pillar attached to front fender top surface.   As this leave the fairing free to vibrate, excited but vortex shedding from his bulky and truncated aft part, additional small chord element is placed vertically on his external side.

Airfoil shape and proper attack angle to the flow grant much less drag than a simple cylindrical turret.   Lots of micro aerodynamics devices are commonly seen on Hypercar class.

Tipo 6 LMHC – Rear mirror: external support used as small vane.  Micro aerodynamics element.

Rear portion of Tipo 6 LMHC bodywork has been developed with downforce generation demanded to rectangular rear diffuser with the central cone, without vertical vanes.   Behind rear wing we can note a tail that on the central part use a blown flap obtained with proper slot on top surface.

This enhance downforce, compared to simpler upward deflection of the trailing edge.   Rear fender tail is terminated with nolder that extend on the entire width.   Behind rear wheel there are 2 panels that works with the wakes.

Again, these elements are optimized to offer a fine tuning of downforce/drag ratio, to respect technical rules.   Exhaust pipe is integrated at the base of single support of rear wing, same as F1 practice.

Tipo 6 LMHC – Rear diffuser, tail blown flap, panels behind rear wheel.

With all race cars, chassis is the core. Hypercar technical rules dictate high level of safety that requires homologation cycle by either static test and dynamic test.

Several static loads are applied to different part of the chassis to make sure that structure is capable of withstand that prescribed load cases.   Then crash test are performed to the built to verify energy absorption and admitted deceleration profile.

We can note that Tipo 6 LMHC has a raised front part that enable the undernoose shape that we described on previous drawing.   The construction looks very well done with clear attention to push the stiffness/weight ratio.

Tipo 6 LMHC – Composite chassis design in collaboration with ARS Tech.

This last drawing shows on his left the internal package, starting from front bulkhead.   We can identify  suspensions assy with third element across the top and torque bars cartridge actuated by push rod; wheel drum with integrated brake intake duct and slots for top/lower arms and drive shaft.

Endurance races need to be able to work/replaced damaged components in the shortest time possible, this guide the installation that still need to satisfy classical parameters limiting where possible any performance compromise.

Tipo 6 LMHC – Internal package, suspension, drive shaft, wheel drum and brake intake.


Article: Ing. Riccardo Romanelli

Drawings: ©AntonioPannullo

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