As Alain Prost is set to be reunited with one of Formula One’s most prolific machines, we take a look at what made the McLaren MP4/4 so dominant.
The four-time World champion is set to drive the MP4/4 at the Goodwood Festival of Speed this weekend, as Formula One continues to celebrate 75 years of the sport.
Alain Prost reunited with iconic McLaren MP4/4
Icons of the sport come in various guises, be it drivers, designers, team principals or in this case, the car. The domination of the McLaren MP4/4 in 1988, with 15 victories out of 16, 10 of which were one-two’s, has led to it being one of the most recognisable machines in the sport’s illustrious history.
But, whilst it had two of the sports giants behind the wheel, it still had to provide the necessary performance to propel them ahead of their rivals and it did so with a combination of design details that set it apart from the rest.
Ayrton Senna’s arrival from Team Lotus also coincided with McLaren’s switch to the 1.5 litre turbocharged RA168-E Honda engine, with the team having spent a number of years using the TAG-Porsche engine prior.
Honda had worked tirelessly to overcome the governing bodies desire to reign in the turbocharged engines and restore parity with the naturally aspirated engines within the field. This resulted in boost pressure being capped at 2.5 bar for 1988, rather than 4 bar, whilst the total allowable fuel was set at 150 litres, rather than 195 litres.
McLaren began working with Honda ahead of the ‘88 season, as you’d expect, creating a mule car, the MP4/3B, as a means to understand how the engine would perform in comparison to the TAG-Porsche they’d become accustomed to.
Honda had also worked closely with fuel supplier, Shell, in order to mitigate any issues arising from the changes made to the regulations. As such, the fuel would be preheated, such was its exotic aromatic hydrocarbon content.
McLaren also took advantage of some of the groundwork laid by Team Lotus, who’d worked with Tilton during 1987 to develop a smaller clutch than many of their competitors. It measured 5.5” rather than the 7.25” diameter, which was partly driven by the low crankshaft that the Honda engine featured.
It was noted that this design resulted in superior heat management, smoother engagement and had a higher torque capacity, but also required McLaren to rethink their gearbox design.
Gordon Murray, who’d also arrived at McLaren ahead of the season, was one of their personnel to work with long-time Brabham contributor Pete Weismann to collaborate on the design.
A triple shaft arrangement was decided upon in order to take advantage of the low crankshaft position, rather than having to tilt the engine, as Team Lotus had done when using a two shaft gearbox arrangement instead.
A small, but interesting detail, whilst we’re looking at the rear of the MP4-4 is the endplate float (arrowed and inset), which was used as a means to keep the endplate from drifting away from the centreline but couldn’t be directly attached to the diffuser, otherwise the forces acting on the rear corner would shatter the endplate.
The float therefore allowed the bottom tab of the endplate room to bob up and down, without escaping laterally. But, also if we think about this in a modern context, it may have also helped from an aerodynamic perspective too.
The lowline approach seen with the gearbox also filtered into the rest of the car’s design, with parallels between the design of the BT55 obviously drawn because of Murray’s arrival from Brabham, albeit it should be noted that McLaren’s predecessors already had some of this running through their DNA anyway.
Furthermore, the regulations also pushed design in this direction, with the cars becoming more elongated, something that seemed more pronounced by the driving position being taken up, whereby they sunk down in the cockpit more, like they were sitting in a bathtub.
New regulations had also forced a rethink in this respect, as the drivers feet had to be sat behind the front axle line, something that was able to be offset in terms of overall car length due to the smaller fuel tank they’d use.
Overhauling this section of the car, McLaren also redesigned the front section of chassis to include flatter sides, increasing torsional rigidity, as they abandoned the V-shaped design that John Barnard had championed on previous McLaren cars.
The arrival of composite materials, including Carbon Fibre, had been a revelation for Formula One during this era, with McLaren one of the first teams to fully embrace its use. But, prior to the MP4/4 they’d been reliant on Hercules Aerospace for materials, assembly on site and the use of an autoclave elsewhere, something which McLaren remedied ahead of the 1988 season.
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This brought manufacturing back in-house, although Hercules Aerospace still stayed on as a sponsor and supplied the prepreg materials, of which more and more was being used across the car as time went by, including the introduction of a carbon fibre nosebox on the MP4/4.
McLaren continued to use male tooling, rather than making the switch to female tooling as many of their rivals had, which increased their adaptability if they’d made a mistake or found development wiggle room.
It also meant that with a flat panel approach they could have a strength benefit over those using a female mould, as McLaren could use unidirectional carbon fibre fabric as part of their production methods.
The last piece in the monocoque jigsaw puzzle was the drop-in structure referred to as the bathtub. Essentially it made up the entire cockpit region, of the seat back bulkheads, dashboard and side panels and was to be made up of one piece and would further improve structural integrity and torsional stiffness.
The first race, in Brazil, is the only time you’ll see the roll hoop in its unpainted state (arrowed), as the designers wanted to reduce the amount of weight on the car as much as possible, especially at the highest point.
This would obviously allow them to use any weight that they got below the minimum (540kg) as ballast too, placing it in a more desirable location from a Centre of Gravity perspective. (It’s worth noting that in order to try and help balance the naturally aspirated cars, with the turbocharged ones, the N/A cars minimum weight was 500kg).
However, at the San Marino Grand Prix, Ron Dennis had decided that the roll hoop being white would allow the drivers markings and more importantly, Boss’ sponsorship logos to occupy more of a prime position on the car (inset), rather than beside the cockpit as it had in Brazil.
The MP4/4 didn’t really have any stand out visual features when it comes to the car’s aerodynamics, an oddity when we consider its modern counterparts.
Nonetheless the car did feature three distinct aerodynamic configurations throughout the season, in order that they had the flexibility to overcome the challenges of any given circuit, which can be seen in how the two-element front wing was set up based on their choice of rear wing and the balance required by the driver.
In the image above we can see the three rows of drill holes in the endplate, which provide incremental steps in the upper elements angle of attack, in order that the driver could have the wing set at an appropriate level.
The MP4/4 featured vertical outlets on the side of the sidepod bodywork, rather than the top mounted ones seen previously, which opened up the opportunity to use the periscope-style turbo feed snorkel on the sidepod’s upper surface (inset). These would be removed midway through the season, at the British Grand Prix, as they incorporated the inlet within the main sidepod intake (arrow).
The MP4/4 is, without doubt, an era defining machine and can easily stand alongside other worthy contenders that can be considered to have the G.O.A.T status. It also provided a fitting end to the sports first foray into turbocharged machinery, as the naturally aspirated engine took centre stage once again in 1989.
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