GINETTA’S NEW LMP1 TAKES SHAPE
Remember the days when Le Mans challengers were built in sheds? Whether it was somewhere in the French countryside, a London suburb or the wilds of Norfolk, many great cars were born out of rather basic premises.
Those days are now well and truly gone. When British firm Ginetta announced plans to design and build a new privateer LMP1 prototype, it had two options. Treat it like a true privateer project and do the work in-house – admittedly in Ginetta’s modern, well-equipped 75,000 sq ft ‘shed’– or go the whole hog and treat it like a works operation.
Reading down Ginetta’s partners list for the P1 project makes it very clear that the Leeds firm has gone for the second option. While LMP1 will be merged into a single class next year, this project is still firmly aimed at privateers. But the level of detail and resource being thrown at the new P1 makes the development of the car nothing short of a full works project.
Ginetta plans to sell the P1 to customer teams instead of run it directly from the factory, keeping with the privateer ethos.
The concept behind the Ginetta P1 is to provide an off-the-shelf, turn-key prototype capable of winning Le Mans and the FIA World Endurance Championship for customers. That’s a big ask, so Ginetta – already a major global sportscar brand itself, let’s not forget – opted to go big with its partners list to get it right.
The monocoque is being fabricated by A.R.S Tech in Italy before it is shipped back to Britain for final assembly at Ginetta’s HQ. But the actual design of the machine is very much British, as is the brains and facilities behind it.
Ginetta has also partnered with the Williams F1 Team, and has been using its Oxfordshire technical centre to put the new P1 through its paces in regular aerodynamic windtunnel testing.
Before the new car hits the track next month for its first tests, it will have already undergone close to 300 hours of running in the windtunnel, where the team is refining every aspect of the design.
“This is a very exciting time in the P1 project,” says its head designer Pete Smith, who has a strong history in prototype engineering and a stint with the all-conquering Audi Sport team on his CV. “We’ve chosen all of our partners in the project wisely, they’re mostly people we’ve worked with before. Ginetta’s ethos is to do as much in-house as possible, but it’s about managing timescales and there’s so much going on [with the firm’s other GT and engineering ventures] that out-sourcing in some cases is the best option to match the deadlines to the workforce. Especially with a car that has a lot of bespoke parts that are made to our own design.
“We have the capabilities to do things like the structural monocoque chassis in-house, but it makes more sense to have A.R.S do it and we do the majority of the machining and parts design instead. Same with the [Mecachrome] engine and [Xtrac] gearbox. The engine will run direct injection to fit our efficiency needs and the gearbox casing is our own design, optimised to our suspension, our aero and our packaging. There aren’t many off-the-shelf bits. It costs more, but we know we’ll have the reliability from the custom design.”
One thing Ginetta has done entirely in-house is the design of the car. The firm first dipped its toe into prototype design when it blazed a trail and made LMP3 a reality. Ginetta kickstarted the P3 revolution and, while it has now largely stepped back from that arena, the project brought valuable experience to use as a foundation for the P1 programme.
“We learned a lot from the P3 project,” says Smith. “It didn’t just teach us about designing a car, it taught us about methods of manufacture, lead times, assembly and certain logistical things. There’s a lot of knowledge there that can translate into the P1.
“Your base for a car is always the regulations. Your chassis must be a certain design and dimension, and things are scaled up from P3 for P1 in many respects. The regulations are a similar pattern and written to the same fundamental idea. The parts may all come from a different design, but they’re from the same mindset.”
With the chassis design largely formed by the regulations, it’s over to Ginetta’s design department – overseen by technical director Ewan Baldry – to give it the right bodywork, and that’s taken a long and thorough process.
Ginetta made its choice of engine and gearbox early, meaning the skeleton of the P1 has been in place for a while, allowing the design team to work on tailoring the skin of the car to make it the best fit.
Chassis advisor on the project, ex-peugeot 908 LMP1 designer Paolo Catone, says making the drivetrain choice early was key.
“Internal integration is the best thing you can do when designing a car,” he says. “If you build the car around the engine, not the other way around, you can accurately predict the stiffness of each element. If you just say ‘I have a hole here, put an engine in it’ that’s the most compromised thing you can do as you often allocate space you don’t need.”
The early choice doesn’t just benefit the chassis either. It allows the car’s bodywork to be optimised too.
“From an aero point of view, having things like the drivetrain decided early is massive,” says Andy Lewis, Ginetta’s head of aerodynamics, who formerly worked for Williams itself. “People don’t realise how much revolves around the optimisation of
the engine and gearbox. Everything from the sidepod outlets to the cooling blockages and even the car’s entire wheelbase is affected by it.
“When you develop aero for a car you basically have two targets – a downforce [or drag] target and a cooling target – and you have to find the best balance. The level of drag ultimately dictates your top speed, but you must also cool the car efficiently. You need shapes working in both ways.
“We’ll design and simulate a surface in CFD [computational fluid dynamics] and then react and mould it and try to spot a trend in the data that shows a performance level. We’ll send Williams the design and they’ll build it into a surface for the windtunnel.”
Ginetta’s P1 windtunnel model is nothing short of astonishing. It is, in essence, a 50 per cent scale model of the entire final car, minus a working drivetrain of course.
The model must be advanced to get the most from the Williams windtunnel, which does a lot more than simply throw air at the model. The tunnel has an active floorplate, which acts like a treadmill and can simulate running at speeds of up to 112mph. Doesn’t sound huge, but remember this is all to 50 per cent scale. Along with that it can reposition itself to simulate yaw, pitch and roll, meaning the computers can essentially simulate a full lap of a circuit at speed.
Ginetta’s model runs full working suspension under the skin, as well as having ‘masses’ installed to act as the blockages of the engine, gearbox and radiators. Even the wiring is replicated to scale, complete with connectors. On the skin, the model runs close to 100 pressure sensors monitoring the airflow over, and through, the design. It even has real pneumatic tyres.
“A lot of work goes into the model, almost as much as the entire finished car,” says Lewis. “We’ve fully replicated the suspension and the geometry from the full-size car. We have wishbones and flexions to make it as real as possible.
“As the model moves from one position to another on the rolling road we can make sure there’s no hysteresis, or lag, in the process as we have the suspension and parts flexing as they should. We need to make sure that when we go from one position to another we ensure that the forces acting on the car remain constant and return to exactly as they were before it moved. That isolates the aero forces and reduces the ‘noise’ in the system to make the results easier to find.
“Having pneumatic tyres is a big thing. Running scale versions of what we’ll actually be racing on means we can better understand how the tyre will behave on the real car. We can put a pressure sensor under a tyre and look at the contact patch initially, and then subject the model to varying forces and track how that contact patch changes. That way we can experiment with things like camber and set-up options and see the results. We can even track the shape of the sidewall by applying lateral load with the rolling road and see how the tyres will flex under cornering forces.
“Having the model’s internals to scale too helps massively with judging things like cooling. We can place a blockage with sensors that represents a radiator and track how much air hits the surface of it to gain an accurate cooling level.”
The windtunnel’s computing power also helps Ginetta test multiple bodywork concepts much faster. Its systems are capable of completing 30-40 CFD runs in around 15 minutes, whereas a single run back at base can take more than an hour.
Of course, correlation is a concern. Even the best Formula 1 teams have complained about getting lost in numbers as their windtunnel testing has led them down a path that simply hasn’t translated on to the track. Until the P1 tests in earnest, Ginetta is using combined computer and tunnel testing to guide its development.
“With the tunnel tests we’re trying to see what the forces are doing around the car and where the flow is going,” adds Lewis. “They key is finding where the differences are between those results and what we see in CFD. It’s about understanding why a CFD design didn’t match a windtunnel model and moving forward from that is the best way of troubleshooting. If you see something promising in CFD and the tunnel then correlates with it then you instantly have a confidence that whatever you’re working on will work on track to some degree.”
With LMP1 cars being allowed multiple bodywork configurations – from high downforce to low – Ginetta can test multiple iterations in the windtunnel and view the results. It’s not a case of cobbling together one or two engine covers, it’s hundreds of fine-tuned iterations across the board.
“We still have a lot of work to do to make sure the tunnel correlates to the track,” says Smith. “The most important thing for us is to understand where the car is at any one time. So you know what every change does.
“Fortunately with the WEC and Le Mans we know where we’re going track-wise. So we know that in Mexico, for example, it will be the worst-case scenario for us due to the altitude and the demands it places on cooling. We know what the targets are for there so we can tune the car toward them.
“Everybody always says Le Mans is a low-downforce track, but you can’t label it as that as there are some sections of it, such as the Porsche Curves, where it’s very important to have good downforce. It’s about finding that blend between drag, downforce and cooling to develop the best package.”
It’s currently difficult to benchmark the Ginetta P1’s performance targets, due to the low entry in the privateer P1 class this year. As such a lot of the benchmarking is done against the improvements of the LMP2 class. Engine and downforce upgrades have helped P2s lap faster than ever before. This year’s field lapped almost as fast as the monster-powered LMP1 offerings of Peugeot and Audi from the late 2000s.
“We’ve worked hard to understand our competition,” adds Smith. “Granted there aren’t so many direct comparisons out there right now, but we do have big comparisons to draw from LMP2 – from where they’ve come from to where they are now. You can tell a lot about engine and aero development from that performance gain and where the lap time is made. We’ve done a lot of simulation around our aero, weight distribution and weight limits, so we’re confident we know where we’ll be when we start testing for real.”
With the future of the factory LMP1 category still up in the air with just Toyota remaining, the longevity of the class likely lies with the privateer entries. Ginetta is leaving no stone unturned to try and create the fastest turn-key car in the field, which may well wind up leading overall come Le Mans next year. ■