|The first running prototype wears a fiberglass body and a strategically placed prancing horse badge on its front flanks. The production car’s body panels will be aluminum and composite. |
“What better way to celebrate the centennial than looking backward and looking forward,” says Chris Theodore, vice president of product development. “It’s a great way to celebrate one of the greatest racing cars of all time, but actually take it forward into a road car.”
Theodore says that secondly it’s a halo product. “We wanted to have a product that’s kind of a lightning rod. Imagine one of these sitting in the dealer showroom. It certainly polishes the Ford oval and establishes an icon of all icons.”
But the last reason may just be the most valuable. Ford is using the GT program as a technological proving ground for how new product programs will be done in the future. SVT Program Director John Colletti says, “Everything we’re doing on this car is unprecedented –the way we assemble the car, the way we’re pursuing the project, the timing of the project, the cost of the project, the investment and the engineering.” Chief Program Engineer Neil Hannemann knows about ¡®halo cars.’ He was the lead product development engineer for the Dodge Viper program, before coming over to Ford to head up the GT team.
The GT program got the okay from Ford executives Bill Ford and Nick Scheele in January, after the concept car made its debut at the North American International Auto Show in Detroit. It was decided that a production version of the GT would go on sale in the summer of 2004. The timing was quite an undertaking for a car of this magnitude.
“We spent the better part of a week going through and trying to figure out everything we could do using the current technology,” Hannemann says. “The ways you could cut corners –the ways you could save time.”
Hannemann says that a lot of time was taken out of the beginning of the program by doing all of the design, engineering and analysis virtually. This is the first totally virtual program that Ford has done. “We needed to compress the virtual time,” Hannemann adds. “The design had to happen simultaneously with the engineering. So that determined how we set the team up.”
Though the decision was made in January, actual work on the project didn’t begin until May 1, when the hand-picked team of engineers was assembled. Everyone working on the project was put into the same room.
“We started design reviews immediately on sight,” Hannemann says. He adds that there were weekly reviews where the whole team came together to go over the entire car as well as many adhoc meetings held around CAD terminals, with engineers, designers and suppliers interacting in real time making onthe- spot decisions.
The supply base was linked to the same CAE system allowing them to look on in realtime during the main table review. Ford carefully picked the supply base, signing on suppliers with experience in doing low volume vehicles and doing them quickly. This will be the first program for Ford CAE-wise that we only had one level of prototype for crash testing.
“Six months ago,” Hannemann says, “we had a frame and an engine, and we started working on the car from there. Our designs are firming up, we’re building prototypes and we’re to the point of starting production tooling. What’s happened between May and where we are now is a model of the continuous transformation we’re going to be making in creating product in the future.”
“Everything we’re doing on this car is unprecedented. The way we assemble the car, the way we’re pursuing the project, the timing and cost of the project, the investment and the engineering.” — John Colletti, SVT Program Director
|The GT space-frame is all aluminum, made up of extrusions, castings and a few stampings. Four large castings create the mounting points for the suspension. New technologies include the first automotive use of roll-bonding on the floor panels and friction stir welding on the center tunnel. |
|The double wishbone suspension and coil-over shocks are mounted to large aluminum castings. Front crash-beams are also bolted to the castings and can be easily replaced if damaged by a minor frontal impact. Brembo will supply the entire braking system. |
Ford developed them first using modeling techniques, then the team convinced Ford management that if they let them buy a $140,000 Ferrari 360 Modena, they’d take very good care of it. “We wanted to know how well this car performed,” Mees says, “and the only way to do that was to measure it. In order to measure the torsional stiffness, you have to disassemble most of the vehicle. So that’s what we did.”
Without the blessings of upper management, the Ferrari was disassembled and chassis was twisted. After measuring the Ferrari 360 they found that the Ferrari’s torsional stiffness was right where they had set their targets. The Ferrari measured just under 16,000 ft. per degree of torsion. The GT design exceeded those targets by 40 percent. “If you have the stiffness in the chassis,” Mees says, “you can fine tune the suspension and NVH will follow.”
The chassis is an aluminum tubular space-frame made up of extrusions (with castings in key nodes and areas for strength) and a number of stampings. “We knew that this was going to be a light and stiff structure,” Mees says. “We have a lot of experience with it, a lot of lessons learned which we have applied, with the aid of the Ford research lab.”
The A-pillar, header-beam and rear-support for the clamshell are bent extrusions, and the whole structure is welded together. Some bonding is done in the floors and the rear bulkhead. Four main aluminum castings serve as mounting points for the suspension.
“We did this to maximize the stiffness of the attachment points,” Mees says. “It also gave us flexible geometry for those attachment points.”
The engine is not a stressed member of the chassis due to the NVH concerns, a lesson learned from Ferrari’s F-40. Another casting connects the tunnel to the bulkhead and to the rest of the vehicle.
The Ford GT’s floor panels utilize the first automotive application of roll-bonding. Two thin sheets are rolled into each other. In between the two sheets is a silk-screened pattern of graphite. As the sheets are rolled with high pressure and heat, they bond to each other except in the areas where the graphite sits. Compressed air is blown into an opening and the two sheets inflate. What you have is a very strong lightweight construction.
The tunnel is constructed in several pieces. The top of the tunnel is done on a press brake and the flat side panels are “Everything we’re doing welded to the tunnel using friction stir welding, another aircraft technology. The two panels overlap and something that looks like a drill bit with a small nipple on the end spins at 10,000 rpm. The heat from the friction melts the aluminum and the little nipple stirs the molten aluminum together creating a very clean and very strong weld.
Crush rails are bolted to the four main castings allowing for ease of replacement. Low-speed impacts will only damage the crush rails and not the rest of the car.
|A blow molded 18.5 gal. fuel tank runs down the middle of the car. Two internally mounted fuel pumps feed the two injectors per cylinder. Fuel mileage is estimated at a combined 17.5 mpg. The cooling module includes a 3 in. thick radiator followed by an intercooler radiator and condensor. A water air intercooler is mounted right underneath the supercharger and driven by electric pump, continually circulating water.|
235x45x18 Goodyear tires mount on 9 in. rims on the front and 315x40x19 Goodyears mount on 11.5 in. rims out back.
The Ford GT’s aluminum body panels will manufactured by Mayflower Vehicle Systems of Farmington Hills, Mich. Body Structure Supervisor, Bill Clarke says that they chose aluminum over composites, like SMC, for weight savings. They were also able to rely heavily on the technological expertise used by Jaguar and Aston Martin. The aluminum quarter panels, fenders and doors are made using a super plastic forming process, where the sheet of aluminum is heated to near melting and slowly formed to a one-sided die. The space frame will have attachment points for the body panels to hang from in a manner that allow for precise fit and finish.
The forward-tilting hood is made of carbon fiber because of the need to form the very deep air scoops. “They were made deeper than the concept car,” says Clarke, because CAE modeling showed that it helped with engine cooling.”
|The undercarriage is completely sealed. The rear splitter was designed and tested in the computer before a 4/5- size model was made and tested in the wind tunnel.|
The doors are made from a one-piece outer and one-piece inner with pins at the top to hold the doors down at high speeds. One of challenges that engineers faced was how to design the side windows so they would go down.
The original car had flush glass riveted to the body. They solved the dilemma by depressing the window surface into the car slightly and adding a molding around the edge. The side scoops were also pulled out.
|Care was taken to create a historically correct interior, complete with offset speedometer. Lear-designed racing seats are still under development.|
The team used a lot of advanced CAD tools to develop 3-D models of the interior. A virtual digital occupant tool allowed them to adjust the positioning of interior components. The software could also be programmed to adjust parameters for height and size of occupants.
With this ‘immersable’ tool, an engineer wearing a headset with stereo screens and target locators on his body can virtually sit inside an interior buck.
The GT will be powered by an all-new supercharged overhead cam 4-valve 5.4 L V-8, derived from the modular architecture. Rated at 500 hp and 500 lb.ft. of torque, it’s mated to a Ricardo short-throw gateless six-speed transaxle. The Romeo, Mich.- built engine will have an all-new aluminum block and new heads modeled after the Cobra R heads for high flow. The supercharger is an Eaton screw-type compressor. Ford considered a twin-turbo setup, but short development time left no room for powertrain development, not to mention packaging and thermal issues.
The engine uses a dry sump oil system to allow for the engine to sit lower in the chassis. An oil tank is mounted to the passenger side of the engine compartment.
The aluminum block will be unique to the GT for now, but Colletti sees lots of potential for the aftermarket. Coletti says that the block is an exact swap for the iron block in the Lightning pickup and could possibly find its way into some future SVT products. Air will be fed to a dual-element air filter that is built into the back of the body. The exhaust manifolds are cast iron and “as header-like as we can get” says Powertrain Engineering Supervisor Curt Hill.
“We’re paying a lot of attention to make sure we get enough flow,” Hill continues. We have an active muffler system to give us the sound quality we’re looking for.” The muffler has an internal by-pass that opens at a certain pressure level and allows for the drive-by. “There’s a lot of modeling done,” Hill says, “because it’s hard to get the sound quality you want on this short of a run.”
The Ford GT will be assembled at Wixom’s prototype build center, on the grounds of Wixom Assembly in Wixom, Mich. They should easily handle the 1,000 copies that Ford plans to build in the first year. Mayflower Vehicle Systems will supply the chassis and body panels — Saleen Inc. will deliver painted body panels and interior modules. About 15 percent of the vehicle will consist of carryover parts such as the hood latch and airbags from Volvo.