The cockpit of BLOODHOUND SSC, the 1,000-mph (1,609-kmh) land speed racing car, was unveiled on June 12 in Bristol, U.K. The state-of-the-art carbon fiber monocoque has been tailored to the needs of driver Andy Green during record attempts in the South African desert in 2015 and 2016.
Hand-crafted by URT Group (Bagnor Regis, West Sussex, U.K.) using five different types of carbon fiber weave and two different resins, the monocoque has taken more than 10,000 hours to design and manufacture. Sandwiched between the layers of carbon fiber are three different thicknesses of aluminium honeycomb core (8, 12 and 20 mm), which provide additional strength. At its thickest point the monocoque includes 13 individual layers but is just 25 mm in cross section.
The structure weighs 200 kg and bolts directly to the metallic rear chassis carrying the jet, rocket and racing car engine. The carbon front section will have to endure peak aerodynamic loads of up to 3 tonnes/m2 at 1,000 mph (1,609 kph), as well the considerable forces generated by the front wheels and suspension. It will also carry ballistic armor to protect the driver should a stone be thrown up by the front wheels at very high speeds.
The roof of the cockpit has been designed to create a series of shockwaves that will channel the air into the Eurojet EJ200 jet engine. If supersonic air reaches the jet engine fan blades, the airflow will break down and the engine will "choke" (known as a "surge"). This can generate huge changes in pressure that could damage the jet engine and car, hence BLOODHOUND SSC will use shockwaves over the canopy to slow the airflow from more than 1,000 mph (1,609 kmh) to just 600 mph (643 kmh) in a distance of about 1m. Deflecting winds travelling five times faster than a hurricane will, however, cause additional noise and vibration to be transmitted into the cockpit.
The sound levels expected in and around BLOODHOUND SSC are being carefully evaluated. The cockpit is positioned in front of three incredibly loud motors: the jet, a cluster of hybrid rockets and the racing car engine that drives the rocket’s oxidiser pump. Collectively they will generate a noise level estimated at 140 decibels. Much of the noise will be directed backwards, away from the driver. And at more than 750 mph (1,207 kmh) the car will out-run its own sound waves. However, the project’s engineers still anticipate that shockwave and jet intake noise levels may produce more than 120 decibels inside the cockpit. Green will wear an in-ear communications system specially made by Ultimate Ear to protect his hearing and to ensure that he can communicate with mission control.
BLOODHOUND has a highly specialised windscreen custom-made by PPA Group from acrylic. The plastic is heated, stretched and then two layers are bonded together to create a 25-mm section, thicker than a fighter jet’s windscreen and sufficient to withstand impact with a 1-kg bird at 900 mph (1,448 kmh). Due to the oblique angle at which the windscreen is set, the driver will in fact be looking through 50 mm of curved plastic. The key challenge has therefore been to make the screen robust while maintaining absolute visual clarity.
Green has drawn on his experience of flying fast jets and driving World Land Speed Record winners Thrust SSC and JCB Dieselmax to design the dashboard and cockpit layout. Good ergonomics are vital given that BLOODHOUND SSC will cover a mile in 3.6 seconds, or 150m in the (300-millisecond) blink of an eye.
The central screen shows the speed in miles per hour and Mach number, calculated by GPS, plus jet engine and rocket outputs. Dynamic speed indicators help Green to judge when to fire the rocket and deploy the braking systems. Wheel loads are also given prominence. BLOODHOUND does not use aerodynamic downforce, as a Formula 1 car does, while lift at the nose or rear axle must also be avoided at all costs. The need to carefully balance forces throughout its 1000-mph speed range is one of the major reasons why shaping the car has taken 30 design-years.
Green enters the cockpit via a carbon fiber hatch, 500 mm in diameter, just below the jet air intake. At full power, the EJ200 fan sucks in 65 m3 of air per second, so the hatch will be fastened using latches able to withstand loads of 2.5 kN to prevent it from getting ingested into the engine.
During the day ambient temperatures will approach 40°C/104°F, though BLOODHOUND SSC will most likely not run in conditions above 25°C/77°F as the metallic sections of the car will get too hot for the team to handle and the jet engine is inefficient when burning hot, less dense air. Cockpit temperature is still expected to approach exceed 35°C/95°F, so external air conditioning will be used to cool it prior to each run, though this is primarily for the comfort of the electronics, not the driver.
Green will keep BLOODHOUND SSC on course using a bespoke 3-D-printed titanium steering wheel, shaped to his hands and finger reach. Buttons on the front control the EMCOM radio, airbrakes and parachutes, while triggers on the rear of the handgrips prime and fire the rockets. BLOODHOUND engineers developed several design evolutions of the wheel, the last of which was finalised for manufacture by Cambridge Design Partnership. BLOODHOUND has a conventional steering rack with a 30:1 ratio (compared to a normal car of around 15:1), though its long wheelbase makes for a very large turning circle: 240m, compared with 10m for a typical family hatchback.
BLOODHOUND SSC has pedals like a regular car, though once again, they are custom designed for Green. The right-hand pedal throttles the EJ200 jet engine and will be used to start the car moving. The left pedal controls the wheel brakes and will be used to slow the car at speeds below 200 mph (321 kmh). The wheel brakes will only contribute about 1 percent of the total braking effort, reducing the stopping distance by around half a mile. Braking speed is critical, as using the wheel brakes above 200 mph (321 kmh) will exceed their energy capacity and set fire to them.
During a 1000 mph (1,609 kmh) run, BLOODHOUND SSC will cover 12 miles (19.3 km) in 2 minutes, exerting an acceleration force of almost 2G and peak deceleration force of 3G on Green. This long-duration G force is another experience unique to BLOODHOUND: an F1 driver may experience higher G forces, but they only do so for a few seconds at a time. Green will be seated in a carbon fiber seat, molded to his body shape by Real Equip, and manufactured by URT Group. This seat installation will provide unparalleled levels of support and safety for the driver, who will be angled back and strapped in using a Willans five-point harness. Green will also wear a Pro Ultra HANS device to protect his neck from sudden, violent movements or decelerations, and an Arai helmet.
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