At the rear deck, you are able to witness the exhaust outlets. For more downforce, they used the concept of the blow diffuser, although in a slightly different manor. The rear exhaust plume will hit the lower rear wing main plane to help push down on the car. Come Spa and Le Mans, Onroak moved the exhaust outlets to the very rear of the car, so they couldn’t be used for a downforce benefit. This is a neat setup change teams can do.
Come Le Mans we were able to witness the high bulkhead height. This is an ageing downforce concept, but works very well still. Keeping a high nose means flow can accelerate to the rear diffuser more, so the venturi effect (expanding high pressure air) can be even greater. By having a low nose means the splitter and foot plate would have to generate most of the downforce. Ligier would take away the fluid projectile method of the Coanda effect at the rear, as this downforce generator can provide an extra 10%, which simple was moving the exhaust to the very rear of the deck.
For controlled flow to the rear, Ligier have four side louvres which are twisted. This will control the flow down the side of the car, of which will be a very smooth profile. By having this controlled, the rear wing and diffuser will produce less vortices so less drag, so more speed is gained.
Many components of the Ligier JS P2 have much in common with the Onroak version of the Perscarolo 01, so much so that the rear ends of each are almost interchangeable and many components are identical.
Looking back at the rear wheel pod and the slats within, these slats help use the rear tyre wake as downforce. When the air hits the slats, the rear outer ends of the car is pushed into the ground, so is basically and full width diffuser in a way.
The Ligier JS P2 is a brilliant little LMP2 racer. With more than average aerodynamics and chassis internals, the car has had great success in America as well as WEC and ELMS championships in Europe. It’s also only in its second year of development, so there is much more to come from Onroak.
When Dome released images of the S103 early in 2014, the wind tunnel model showed it was clear that the car had a number of innovative features of which its designers and engineers pinned hopes it would bring it to the front pack of LMP2 racing. Looking at the 60% wind tunnel model, its notable that the car features ‘handlebars’ on the top of the monocoque survival cell. This allowed the car to have a much lower cockpit ride height, therefore reducing frontal area and coefficient drag levels. What's unique about the car, is that all of the bodywork panels are 3D printed, which is brand new to LMP2 racing, and great way to cut costs.
On the side on the Strakka Dome S103, it had a number of evolutions from its original roll out spec to its testing trim, where a long plate had been added to the rear of the front wheel plate and a number of turning vanes added above the front suspension set up. At Spa the car featured two vertically mounted fins on the side pod impact structure, this was revised aero package which was balanced between downforce and straight line speed.
By the time the car was homologated ahead of the 2015 season, the side plate had been slightly reworked and the car had gained a side exit exhaust. The turning
vanes above the suspension were also revised and a lot smaller. Many of the car's 3D printed elements can be seen also with lots of side pod slats guiding the air flow for better rear wing and diffuser effects. The Coanda effect is very popular in LMP racing, as it generates lots of downforce as well as very little drag, and is well executed on the Strakka.
When the S103 made its first test runs, the rear wing was supported by the end plates. This is likely a solution because the car was not fully finished during the testing time. Indeed this can be seen with the central attachment sitting awaiting the swan neck mounting. The rear of the car has been extensively revised, the design of the swan neck was retained for a downforce benefit, which is now common on the Ligier JS P2 and the ORECA O5.
During the rework of the car’s rear, the exhausts were repositioned to the flanks of the car while the engine cover grew a large bulge to accommodate new radiators and engine packaging, under the shrink-wrap skin. The trailing edge of the rear bodywork, which initially was curved inwards at its lower edge has been replaced with a flat vane, leaving a small Red plate to fill the resulting area.
At the car’s debut races at Silverstone, it was fitted with a revised front end aero kit. This is standard practice for LMP2 manufacturers before Le Mans. It featured single dive plane for better balance according to Dome.
The standard setup features twin dive planes on the leading edge of the front wheel arch, while the Le Mans version features a box style turning vane. This is not the setup the team wanted to use but the original configuration was not deemed to be within the rules, due to the later twist on the plate. The new design will reduce vortex generation; the converging duct will accelerate airflow out behind it, and the dive plane underside would make lower pressure making it more useful. Although the vortices might create very turbulent and unpredictable flow along with more drag.
The front of the Strakka nose structure had a revised aero concept for the S103, which is totally different to any other LMP2 design. It features a very narrow front crash structure, rather more like a raised nose open wheel car. The towing eye is hidden inside the front support section. Further back the car has very wide and long double mainplane above the foot plate of the car. This section allows air to pass through in a big volume. This same concept has been implemented to LMP1 cars for some time, and recently made its way to the Ligier JS P2. It’s a great way to reduce frontal drag, by allowing lots of air to pass through and out via the side pods. The S103 is very open at the front, compared to the normal design in LMP2 racing. Air will exit via the side louvres on the side impact structure, it will also pass lots of vanes inside the car, so it’s neater as it exits.
For the engine the Strakka LMP2 car has the new and updated Nissan VK45 engine, of which was developed by popular company Gibson. It’s a normally aspirated 4.4L V8, which means no turbochargers are mounted on the car. When looking at the rear engine packaging, Strakka fitted a peculiar exhaust which is very long. It’s unknown what the reason behind it is. The engine produces around 450BHP, which is put onto the road by the super strong Xtract 6 speed gearbox. For rear suspension you can witness the coil spring suspension on top of the transmission. The car also has double wishbone, push rod all round, with aluminium torsion bar up front, in the bulkhead, with six pot callipers brakes all round.
The overall design is very strong from Dome, the low-drag philosophy remains. But it is a question whether the 3D printed parts can live up expectation. Time will tell.
LMP2 has seen some fantastic cars over the years, but we have reached the pinnacle of P2 racing, there is just no more to give with the current regulations. The excitement for 2017 is very clear from any racing fan, as the cars will be a lot safer and have even more advanced aerodynamics, and more importantly, faster.
Image: Octane Photographic