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How the North American Eagle Works

        Auto | Unusual Cars

Major Systems of the North American Eagle

Although the North American Eagle is unlike any car you'll see on the interstate, it has many of the major automotive systems you would find on a production vehicle. Let's break the Eagle down and see what makes it move so fast.

Chassis
The North American Eagle chassis, which maintains all of the basic dimensions of the Starfighter fuselage, is 56 feet long, seven feet wide at the nose and nine feet wide at the tail. As you can imagine, transporting such a large vehicle poses quite a challenge. To move it from site to site, the team uses a Volvo diesel tractor pulling a full-sized semi-trailer.

Suspension
As a plane, the Starfighter didn't require a suspension system to help absorb the shocks and bumps that come from driving over a rough surface. As a car, the North American Eagle must be able to navigate imperfections in the road without losing speed or compromising vehicle stability. The car will only run on a dry mud lake bed that is completely free of imperfections for the entire run distance; no roads. This is why the Black Rock desert is a good venue for record attempts. The team solved the problem by using a gas shock system to suspend the front of the car. The rear suspension is based on a rectangular frame, constructed of rectangular steel tubing arranged in a delta, or triangular, configuration towards the rear. This frame is made of mild (or low carbon) steel, which is cheap, strong and easily shaped.

Gas Turbine Engine
Photo courtesy of the Airplane Flying Handbook
The basic components of a gas turbine engine.

Engine
The turbojet engine that powers the North American Eagle is typical of most commercial and military aircraft. If you read How Gas Turbine Engines Work, you'll see that these engines consist of turbines, a combustion chamber, fuel injectors and a compressor. The compressor sucks air into the combustion chamber, where oxygen is used to burn fuel. As the fuel burns, exhaust gases are directed toward the turbines. One set of turbines directly drives the compressor via a shaft. The other turbines rotate freely and create a high-speed stream of air that is directed through a nozzle. This high-speed stream of air generates thrust based on Newton's third law of motion (for every action, there is an equal and opposite reaction).

The Results of Bad Braking
Land speed racing is not for the fainthearted. In 1964, while making his second October run for the record in Spirit of America, Craig Breedlove had a near-fatal accident when the parachutes on the car were torn from their riser lines. Without the extra drag from the chutes, Breedlove couldn’t stop the car with the disc brakes, which burned out. The car eventually came to rest in a saltwater pond and Breedlove was fished out unhurt. Less than a month later, Breedlove returned to the Bonneville Salt Flats and became the first person to drive a car faster than 500 mph.

The Eagle's LM-1500 engine is the civilian version of the J-79-15 engine used in military aircraft such as the F-4 Phantom. It measures three feet in diameter and weighs 3,840 pounds. The compressor is connected by a single shaft to the turbines and has 17 stages to feed super-oxygen-rich air to the fuel pumped in by the injectors. Both the fuel nozzles and the burn canisters are ceramic-coated, which helps reduce heat and produces 13 percent more power.

At idle, the engine consumes 18 gallons of jet fuel per minute. The team has two different models of the LM-1500; one produces a total of 42,500 horsepower for low speed testing, and a second one has ceramic coatings on the turbine blades and burn canisters, which will produce as much as 52,000 horsepower for high speed record runs.

Wheels
The North American Eagle rides on five wheels -- one in front to steer, two side-by-side on an offset mid-chassis axle and two in the rear. For low-speed runs (under 350 mph), the wheels come equipped with rubber tires. For high-speed runs (up to 800 mph), the standard aircraft wheels are removed and replaced with solid billet aluminum wheels with a titanium band on the outside running surface of the wheel for greater strength and stress retention, machined specifically for use on the Eagle. No tires are used in the high-speed configuration.

Parachutes deploying
© 1996 - 2007 E&D Services, North American Eagle, Inc. All rights reserved.
The parachute deploys to slow the Eagle down on its way to stop.

Braking Systems
Slowing a vehicle down from supersonic speeds requires a phased approach using multiple technologies. Assuming the Eagle is traveling at its target speed of 800 mph, here's how braking works:

  • The driver pulls back on the throttle. In doing so, he deploys speed-brake doors located on each side of the fuselage, just forward of the tail section. Hydraulically actuated, these speed brakes were part of the original aircraft design and function in the same way by creating drag to slow the vehicle down. With the speed brakes deployed, the car begins a gradual deceleration.
  • At about 650 mph, a drogue parachute is deployed to assist the speed brakes. A drogue chute is more elongated and much thinner than a conventional parachute, which means it creates less drag and is less likely to get torn apart. A much larger main chute follows the drogue at about 500 mph, creating even more drag. This slows the car to approximately 125 mph.
  • At 500 mph, the driver can activate the magnetic brakes on the rear wheels to scrub off kinetic energy built up in the massive 300 pound wheels, which tend to spin down slower than the car will decelerate. These are state-of-the-art components made of rare earth (neodymium iron boron, or NdFeB) magnets mounted in stainless steel brackets on the rear axle near each wheel. The brackets move close to, but do not touch, an aluminum rotor mounted on the inside of wheel's hub. The resulting magnetic resistance slows the car to 100 mph.
  • Finally, with the car traveling less than 100 mph, a "Flintstone" break pad (currently in development) just off the cockpit, will hydraulically activate to drag along the ground at speeds below 100 mph.
Cockpit
© 1996 - 2007 E&D Services, North American Eagle, Inc. All rights reserved.
The North American Eagle cockpit

Cockpit
The cockpit of the North American Eagle houses a single driver who is strapped into place by an extra-wide seatbelt with a five-point attachment. Instead of a steering wheel, the driver will find the Starfighter’s original flight stick. A hydraulic system communicates input from the cockpit to the front wheels, allowing the driver to steer the car right or left. A very basic instrument panel, which includes temperature gauges, fuel and oil pressure gauges, air speed indicator and Mach meter, is visible just beyond the flight stick. And a radio enables the driver to communicate with ground crew members and other support personnel who help monitor the condition of the track and other variables that could affect the outcome of the race.


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