Megabuck hypercars have seen some of the most significant and extravagant attempts at electrification through hybridization. Late last year, McLaren Automotive conducted successful maximum-speed runs for its ultimate hybrid, the Speedtail, at the Kennedy Space Center in Florida, concluding its dynamic development program.

The XP2 prototype achieved 403 km/h (250 mph) more than 30 times during tests at the Johnny Bohmer Proving Grounds, culminating the extensive dynamic development process for the fastest McLaren ever. It concluded a development carried out at multiple test venues worldwide, including at the Applus+ IDIADA facility in Spain and in Papenburg, Germany. Hand assembly of the first of 106 custom-order Speedtails started shortly afterward at the McLaren Production Centre in Woking, UK.

“It’s fitting that the Speedtail’s high-speed test program concluded with multiple maximum-speed runs at a location strongly associated with pushing the boundaries of extreme performance and engineering excellence,” said McLaren Automotive CEO, Mike Flewitt. “The Speedtail is a truly extraordinary car that epitomizes McLaren’s pioneering spirit and perfectly illustrates our determination to continue to set new benchmarks for supercar and hypercar performance.”

 

The ultimate in the Ultimate Series

The Speedtail now making its way to customers sits at the top of the company’s Ultimate Series of cars. At almost 5.2 m (17 ft) long, the carbon-fiber-bodied three-seat “hyper GT” is the most aerodynamically drag efficient McLaren ever and a showcase for the brand’s expertise in lightweight engineering.

“The McLaren Speedtail is a vehicle unlike any other, not simply because of the astonishing visual drama, extreme speed, and aerodynamic excellence that distinguish it, but because it sets unprecedented standards in technical luxury and bespoke customization,” said Rob Melville, Design Director, McLaren Automotive.

Its gasoline-electric hybrid powertrain delivers the greatest power and torque of any company road car, with a combined 1070 PS (1055 bhp) and 1150 Nm (848 lb·ft). In addition to ultimate top speed, the straight-line acceleration sets a new benchmark for McLaren Automotive, with 0-300 km/h (0-186 mph) achieved in 12.8 s. (For comparison, the company’s previous Ultimate Series hybrid, the P1, could reach this speed in 16.5 s.)

How does the Speedtail go so fast? The company says that the results are due to a combination of attributes, including aerodynamic excellence and low vehicle weight. Fundamental to this is a race-bred electric-drive system that incorporates pioneering battery technology to set a new benchmark for hybridized efficiency.

 

Hybridized speed

Its M840TQ powertrain comprises a 4.0-L internal combustion engine and an electric drive unit. The V8 features technology evolved from McLaren’s first hybrid hypercar, the P1. A new lightweight air-intake system, improved cylinder head cooling, and a revised piston design contribute 757 PS (557 kW) and 800 N·m (590 lb·ft) of “traditional” output.

The electric motor uses Formula E-derived technology to generate more than 230 kW. McLaren says that gives the Speedtail the highest performance installation—including cooling and integration—of any electric motor currently in use on a production road car. Power delivery is 8.3 kW/kg, which is twice the efficiency of an average sports car.

Engineers from McLaren Applied—the division that focuses on virtual product development, telemetry, electrification, and control—worked with the Speedtail’s electric-drive technology team to integrate its motorsport-developed inverter and DC/DC converter technology into the system.

The high-voltage energy-storage system is where the McLaren says the Speedtail engineers truly innovated. A high-power cylindrical-cell arranged in a unique array, the 1.647-kW·h unit is extremely compact and delivers the best power-to-weight ratio of any high-voltage battery available. An indication of how McLaren technology has advanced is that the power density of this battery is four times that of the unit in the P1, providing 5.2 kW/kg and 270 kW.

The 5.2-kW/kg power density is said to be the best of any automotive high-voltage battery system. Although there is no ‘plug-in’ element—the batteries self-charge through brake regen when the car is driven—the car comes standard with a wireless charging pad that trickle-charges and maintains the battery when the vehicle is not in use.

An intelligent energy deployment system makes these headline figures achievable. The cells are thermally controlled by a dielectric cooling system and permanently immersed in a lightweight, electrically insulative oil that quickly transfers heat away from the cells. A first of its kind in a production road car, the system allows the cells to run harder and for longer.

The 250-mph top speed is achieved in Velocity mode, which optimizes the hybrid powertrain for high-speed running, tailoring the angle of the active rear ailerons, can retract the digital rear-view cameras, and can lower the ride height by 35 mm (1.4 in)—leaving the vehicle height at just 1120 mm (44.1 in).

 

Ultimate aero

Beyond the powertrain, the £1.75-million hypercar features a custom version of the carbon-fiber McLaren Monocage body structure. As in the legendary 1990s-inspired McLaren F1, the driver of the Speedtail is positioned centrally in the cockpit, with seating for two additional passengers set slightly rearward. The seating arrangement allows for a teardrop-shaped cockpit that aids aerodynamic drag efficiency. Other aerodynamic body features include carbon fiber front-wheel static aero covers, retractable digital rear-view cameras (in lieu of mirrors), and patented active rear ailerons.

In addition to the Monocage, other lightweight engineering features are the all-carbon-fiber body, aluminum active suspension, and carbon-ceramic brakes. The total (dry) mass of the car is only 1430 kg (3153 lb).

Many of the exterior design elements of the car have been engineered to reduce drag and maximize top speed. The car is narrower than a P1, but more than 0.5 m (1.6 ft) longer at 5137 mm (202.2 in). Viewed from above, the car is essentially a teardrop shape and so too is the cockpit set on the body.

The vertical ducts beneath the LED headlights are tapered to minimize drag while still feeding sufficient cooling air into the LTRs (low-temperature radiators). Airflow that doesn’t enter the LTR ducts is directed over the hood and enters two upper front clam intakes, then ducted through the body and around the wheel arch before exiting out of the lower door vents. This engineering reduces the volume of air traveling around the side, which is prone to separation from the body and resulting turbulence.

Airflow over the nose of the car is directed onto and over the windshield by a cowling at the trailing edge of the hood to maintain smooth flow over the single-arm wiper and then roof to the powertrain’s flush-roof “snorkel” intake.

Lightweight, carbon-fiber covers, incorporated on to the 20-in forged alloy front wheels to minimize aerodynamic drag, remain fixed in position as the wheels rotate. The covers help to keep airflow attached to the car and guide it to the blades on the leading edge of the dihedral doors. They work in conjunction with multiple air ducts and paths to reduce turbulent air within the wheel arches. The gloss black wheels get custom P-Zero tires developed with Pirelli.

Instead of door mirrors, the car uses two high-definition digital cameras that deploy when the vehicle is started. The significantly smaller profile of the cameras has a minimal effect on airflow and provides a much wider field of the rear view. The cameras feed two screens on the instrument panel sides, and they retract into the doors to reduce drag further for Velocity mode.

The raised front wings, compact cockpit glasshouse, and flush glazing serve to keep the airflow attached to the vehicle, drive it over the front fenders, and into the small but deep channels within the doors to provide cooling for the powertrain’s shoulder-mounted HTRs (high-temperature radiators).

The trailing edge of the car showcases a pair of dynamic, hydraulically actuated active ailerons formed in flexible carbon fiber. They enable the rear clamshell to bend and remove any gaps between vehicle and spoiler leading edge to reduce turbulent air and drag. Positioned outboard, they adjust to move the center of pressure to provide downforce for deceleration (airbrake) and high-speed stability.

Like on the lower door vents, vertical rear blades on the trailing edge of the rear fenders draw turbulent air out of the rear wheel arches and away from the 21-in rear wheels. They help to reintroduce the “dirty” air as smoothly as possible, reducing pressure and drag at the rear of the car.

The rear diffuser works in conjunction with the rear blades to reduce base pressure and drag, achieving this through the fluid merger of airflow from the top and underside of the car. The extended length of the diffuser and flat underfloor combine to diffuse the airflow before reintroducing it into the free stream.

 

Carbon-fiber materials

The Speedtail marks a revolutionary advance in the creation and usage of carbon fiber by McLaren, with state-of-the-art technologies combining with traditional Italian textile knowledge to conceive a “digital loom” process that delivers a lighter composite material formed from an intricate carbon-fiber weave.

Company engineers used the technique to develop a unique carbon fiber and titanium weave called Titanium Deposition Carbon Fibre. For the Speedtail, a micron-thin layer of titanium is fused directly onto the weave and becomes an integral part of the carbon fiber’s construction. The titanium-deposition process is said to combine immense strength and low weight with a finish with a chrome-effect shimmer.

The front splitter, diffuser, and side skirts are all finished in 1K (1000 fibers per thread) version of the material, making it lighter than the 3K alternative and allowing the adoption of a Jacquard weaving process to create an intricate pattern in the fiber elements. The titanium can be anodized in any color or used to create interwoven images, symbols, or even words in the carbon; for example, the rear of the driver’s seat features the McLaren logo.

McLaren worked with Swiss watchmaker Richard Mille on horology techniques to develop a world-automotive-first TPT (thin-ply technology) carbon fiber. The material is comprised of many ultra-thin carbon layers just 30 µm (1180 µin) deep, each positioned at a 45° angle. The surface is then delicately milled to expose a stratified, shimmering construction that resembles flowing water.

The material is integrated into areas of the car such as the overhead control panel, gearshift paddles, and steering wheel clasp. It is also used in the McLaren badge on the front of the Speedtail design model, with both this badge and the Speedtail name formed in 18-carat white gold, the letters being individually pressed, clipped, and polished.

 

Beautiful on the inside too

The vehicle’s glazing was a design focus for enabling as much light in the interior as possible.

The windshield curves to become part of the roof, meeting a glazed porthole above the driver’s head and the glazed upper sections of the dihedral doors. The glass rear-quarter lights stretch back behind the seats to almost the rear axle. If occupants want to reduce the amount of light coming in, the porthole, glazed upper section of the doors, and rear-quarter lights feature electrochromic technology that allows them to independently to instantly turn opaque. The top of the windshield is also electrochromic, eliminating the need for sun visors.

The central seat creates a sense of space and a balanced view out of the windows for the driver. The custom-made carbon-fiber seat’s innovative directional leather finish makes it easy to slide in but subtly holds its occupant in place while they drive. The central seat is flanked by two passenger seats integral to the carbon-fiber monocoque.

Custom luggage, for the storage spaces in the car’s nose and tail, is available to every owner—the carbon fiber, leather, and metalwork on the cases matching the interior specification.

Ahead of the driver is a control system with high-definition displays and touchscreens that nearly span the dashboard that enables removal of almost every button and switch traditionally found in a car. Controls for engine start, Active Dynamics Panel, Velocity mode, and window/door opening are in panels above the driver’s position.

The Speedtail and GT audio system designs by McLaren and Bowers & Wilkins were recognized at the 2020 iF Design Award in the product discipline of the car audio category. The iF awards are organized annually by Hanover-based iF International Forum Design GmbH, the world’s oldest independent design organization. For 2020, the competition saw 7298 entries submitted from 56 countries.

The Speedtail system was commended for its tailor-made grilles. The two companies’ engineering teams worked to create the custom audio system for Bowers & Wilkins’ first system central driving position with design elements including cutting-edge speaker technology with Diamond Dome tweeters and Continuum midrange drivers.