The McLaren MP4/5 picks up the legacy of the winning MP4/4, participating in the 1989 World Championship, driven by Brazilian champion Ayrton Senna and French champion Alain Prost. The 1989 regulatory changes required the British team to no longer use a supercharged six-cylinder engine, but a new atmospheric engine, making the choice fall on a ten-cylinder unit, also Honda.
The new car, designed by engineer Neil Oatley, is an effective evolution of the winning 1988 McLaren MP4/4, which had literally dominated the season by winning fifteen out of sixteen races. The car is characterized by a general decrease in bodywork, especially in the rear, where the Coca-Cola effect is accentuated to the point of disappearing at the level of the body, which continues straight up to the rear.
Like all the other teams, with the return to the aspirated engine, an air-scope is adopted above the driver's head, in order to guarantee an increase in the pressure of the intake air, and therefore in the power delivered by the engine at high speeds.
Berger's spectacular and harmless accident at the Tamburello curve in Imola unexpectedly re-proposes the spectre of fire. The Federation, alarmed by the episode, imposes a series of regulations for the following season, the most important of which is to make crash tests for the body more stringent.
McLaren, while continuing to use the molds of the MP4/5 body, adapts to the new standards by using a composite with a higher resistance carbon fabric, adapting the lamination, relying on the company Hercules for the construction. The front and rear safety roll-bars are also replaced with stronger and higher versions, considering the less inclined driving position.
In the body, the surfaces take on an almost mirror finish, generated by the use in the construction phase that a negative mold was used, probably divided into two shells, one upper and one lower.
As for the suspensions, on the other hand, a deformable quadrilateral pattern is provided at the front made up of two slender overlapping triangles consisting of welded elliptical section tubular steel elements, with the lower triangle adjustable in length using interposed plates of variable thickness in the fixing of the final ball joint, in order to adjust the camber.
The spring-shock absorber unit is instead positioned inside the mechanism with the pull-rod type actuation, and preferred to the push-rod as it is considered more compact and lighter overall given the shape of the car, while the anti-roll system with which the suspension is equipped is decidedly innovative and consists of a rectangular section bar, positioned transversely more or less above the rider's ankles.
The central constraint only allows it to move up and down, and its ends are connected to the suspension levers with two tie rods: in fact, when the car pitches, brakes or accelerates, the bar rises or falls, remaining horizontal without exercising no reaction force on the suspensions, while on the contrary when the car rolls in curves one end tends to go up and the other to go down, but the presence of the central constraint, preventing it from rotating, causes the ends of the bar to flex, producing a reaction that limits the roll.
Furthermore, the pilot can have a lever positioned on the left side of the cockpit, with which the effect of the stiffness of the bar can be varied by rotating it axially.
The rear suspension layout is the same as the front one, with the two overlapping triangles. Specifically, the lower triangle is equipped with an increase of an arm, in order to maintain the predetermined convergence of the wheels. The spring-shock absorber group is on the side of the gearbox with the push rod type leverage scheme, effectively maintaining the same philosophy introduced on the previous car, namely the MP4/4.
In addition, the quick release system of the steering wheel is introduced for the first time on a Formula 1 car, so as to allow the driver to get out of the car in less than five seconds in case of danger. As for the engine, however, Honda is forced to develop a new unit after having finally found the reliability and power with the six-cylinder turbo of the previous season: called RA109E, the new engine is the Japanese response to the regulatory change imposed. by the International Automobile Federation.
The unit features six cylinders with 72-degree inclined banks, capable of developing a power of 644 horsepower at a speed of approximately 12.000 rpm. The project was taken care of by the engineers Nobuhiko Kawamoto and Osamu Goto, two real gurus of Formula 1 engines of the 80s: however Kawamoto is preparing to take on the role of CEO of the house for 1990 to replace Tadashi Kume, therefore from a purely technical point of view, the real father of this engine is to be considered only Goto.
The concept according to which the engine is designed is based on the compromise between compactness, weight and power: after trying different configurations such as a V8, a V10 and a V12 to make comparisons and determine which was the ideal layout, a unit is created. with a very futuristic but at the same time risky architecture, namely the ten-cylinder configuration.
Initially, the big obstacle to overcome lies in the fact that having ten cylinders means arranging them in two banks of five each: this however involves asymmetrical stresses due to the number of odd cylinders on each bank, with forces and moments of inertia particularly dangerous for the integrity of the system, and it is therefore very difficult to study the dynamic behavior of these systems.
Through the analysis of the data and various calculations, the Japanese technicians discover that they can balance the operation of the engine by choosing a bank angle of 72°, due to the intrinsic characteristics of the V10. This is the optimal value to avoid resonance phenomena, with an adequate arrangement of the firing order 1-6-4-9-5-10-2-7-3-8.
Despite this, it is still necessary to use the balancing shafts, unlike what Renault can do with its V10, saving on mass and dimensions. To balance the engine, Honda engineers start with a five-cylinder Audi engine fitted as standard on the cars.
Initially, in order to contain the weight, it was decided to use a timing control with synchronous belt, but at high rotation speeds the system has excessive expansion which leads to variations in the timing which are detrimental to the integrity of the engine and its performance, therefore this' the latter is modified and in the final version is controlled by a cascade of gears, which drive four overhead camshafts, which operate four valves per cylinder.
This engine uses a traditional valve spring system, while Renault introduces the pneumatic springs already tested on the latest versions of its turbo engines. Honda engine valves are built in titanium like the Ferrari, while other manufacturers still use sodium-cooled steel valves.
Base and heads are made of aluminium alloy, while the cylinders are made with removable nikasil barrels. This engine also boasts the entire construction in Japan, given that it has an electronic management system with control unit and indirect electronic injection system designed by the same parent company, the real strength of the Japanese drive unit, while the rest of the components are always supplied by the Japanese NGK and Showa.
In addition to these companies, another very important supplier of both McLaren and Honda should be mentioned, namely Shell, which provides for an exclusive contract with both the Japanese engine engineer and the English team, allowing the oilman to focus solely on the Honda V10s for which he develops fuel mixtures with high calorific and antiknock properties, as well as lubricants specially designed for the Honda unit.
Given the recent success of the previous MP4/4, the English team does not intend to give up its supremacy to rival teams and the MP4/5 does not disappoint expectations at all. The 1989 season turns out to be one of the most spectacular seasons in the history of Formula 1, with the two drivers of the Woking team, Ayrton Senna and Alain Prost, protagonists of a no holds barred battle.
The first part of the season sees the French driver excel, winning three victories in France, Great Britain, and the United States, surrounded by three second places in the first three races of the season in Brazil, San Marino, and Monaco, while Ayrton, also with three victories in the San Marino, Monaco and Mexico Grand Prix, but some slowdowns at the Brazilian and French Grand Prix, and two retirements in Canada and Mexico, preclude his leadership in the standings in favor of his teammate.
During the second part of the season, the Brazilian driver continues to suffer heavy retirements, such as at the Grand Prix raced in Italy and Portugal, but despite the second consecutive retirement in Great Britain that gives the victory to his teammate, Ayrton wins three more victories in Germany, Belgium and Spain, as well as a second place in Hungary and Portugal, while Alain, in addition to the aforementioned victory on English soil, wins a victory in Italy, three second places in Germany, Belgium and Portugal , and a third place in France.
In the penultimate round of the season in Japan, both cars retired following a long battle that culminated in a contact generated by a risky move by Senna, who for this reason was disqualified at the end of the race.
In the final race in Australia, McLaren closed the season with a double retirement: nevertheless, Alain Prost won the drivers' world title with 76 points, sixteen more than his teammate, while the team from Woking, despite numerous retirements during the course of the season, he won the constructors' world title with a total of 136 points.
In the 1990 season, with its MP4/5B evolution, the Woking team tries to reconfirm the double world title won the previous year. The new regulations this time foresee changes in the position of the tanks.
In addition to this, McLaren is forced to adapt the car to Berger's stature, so the air intake above the driver's head is also decreased and raised, while the rear extractor now has five outlets, the front wing bulkheads are completely redesigned and the rear body re-profiled around larger radiators.
The engine, developed by Honda, is optimized in performance and Senna carries out an impeccable development work in order to ensure better reliability.
The 1990 season
The new car allows McLaren to reconfirm at the top of both world classifications. The new rival is Ferrari, which with its 641 F1 returns to the top level of competition, driven by Alain Prost, coming from McLaren, and by the English Nigel Mansell.
Over the course of the season Ayrton Senna engages in a battle with former teammate Alain Prost. The Brazilian conquers six wins, including the first in the inaugural Grand Prix in the United States, followed by victories in Monaco, Canada, Germany, Belgium and Italy, as well as five podiums, including two second places in Hungary and Portugal, and three third places in Great Britain, France and Brazil, having only four retirements over the course of the season.
Alain won five races and conquered four podiums, ending the season in second place in the drivers' championship, only six points behind his eternal Brazilian rival. Gerhard Berger, on the other hand, conquers only seven podiums, of which two second places in Brazil and San Marino, and five third places in Monaco, Mexico, Germany, Belgium and Italy.
Despite the Austrian driver failing to win any races this season, the points earned allow McLaren to take the constructors' world title for the second consecutive time, thanks to a total of 121 points.
Ultimately, the very powerful Honda engine and an exceptional chassis allow Ayrton Senna and Alain Prost to rewrite history with breathtaking duels, with the rampant Brazilian questioning the reign of the French, allowing the McLaren MP4/5 to conquer in two seasons four world titles, sixteen victories, twenty-seven pole positions and twelve fastest laps, obtaining a total of 262 championship points.