May 8, 2001 - In Formula SAE race car competition, the team that can design and produce major components that are lighter in weight, smaller and stronger has a decided edge in the hotly contested battles for top finishes.

When he throttles up to 130 mph or more, it's still a ho-hum experience for this living legend in boating. Even at that impressive speed, the man who invented the famous Arneson surface drive propulsion system yearns for more thrust.

All of those advantages were gained in the car created and raced last year by the Rochester Institute of Technology Formula SAE Racing Team. R·I·T is a recognized leader among colleges and universities worldwide whose innovative engineering students have been developing new designs and concepts intended to be functional in future, improved land vehicles.

Like its predecessors and in accordance with SAE rules, the latest R·I·T Formula racing team of 20 students has devoted all of its collective talent to the design, fabrication and racing of a high-performance formula-style racer. R·I·T team success can be measured by its record of placing no worse than second in five of its last seven years of international competition.

Each year, in competition sponsored by the Society of Automotive Engineers, participating teams build an entirely new race car with restrictions only to the car's frame and engine to challenge the students' knowledge, creativity and imagination. Engineering ingenuity is encouraged, so long as it meets goals allied with those of a production vehicle.

The racer, for example, must be a prototype for evaluation as a production car. It must have sales appeal to the nonprofessional weekend autocross racer who values high performance in terms of acceleration, braking and handling. High marks go to the car that is low in cost (the prototype model must not cost more than $30,000), easy to maintain and reliable. It must be marketable, comfortable, use common parts and have esthetic appeal.

Formula SAE vehicles are very sophisticated, highly engineered small race cars about one third the size of Indy Formula 1 cars. The racer designed and built by the R·I·T Formula racing team is a single-seat, open-wheel, mid-engine car that weighs only about 420 pounds. It is powered by a 600cc motorcycle engine capable of 45 ft. lbs. torque.

Michael Occhipinti, project manager for the R·I·T Formula SAE race car, and the team's chief engineer, John Coppola, directed team effort to completely re-design the current F8 vehicle to maximize performance and ensure durability. Key areas for attention included weight reduction, endurance, suspension, brakes, drive train and safety.

Major Components

Although the R·I·T race car had always been one of the lightest vehicles in the year-round competition, the year 2000 Formula racing team made key components in the major subsystems of the vehicle even lighter - also stronger, smaller and more durable by making them from AerMet® alloy, an ultra-high strength, high-toughness steel developed by Carpenter Technology Corp.

This alloy, originally developed for aerospace applications, is a premium-melted alloy that has offered a unique combination of high strength and hardness, fracture toughness, exceptional ductility, and resistance to both fatigue and stress corrosion cracking. It reaches an ultimate tensile strength of 2069 MPa (285 ksi) and a fracture toughness of 110 MPa √m (100 ksi √in.)

The R·I·T student design team has used Carpenter's AerMet alloy extensively in the suspension and drive train to make major components such as the drive shafts, stubshafts, hubs and spindles both lighter and more durable than possible previously. Initially, the team tried 300M high strength steel for the drive shafts, but has found that the AerMet alloy was stronger.

Drive Shafts Re-Designed

The team completely re-designed and built two new drive shafts from the AerMet alloy, both linking the Torsen-type differential with the two rear wheels. The engineer/students were able to reduce the weight by more than 50% (from 5.10 lbs. to 2.38 lbs.), reduce the shaft diameter by 30% and improve car performance while providing more than enough strength and endurance to eliminate the breakdowns previously experienced. Having used the AerMet alloy in place of 300M alloy, they also were able to redesign and strengthen the stubshafts which link the differential with the CV joint.

On a car that weighs only 420 lbs, Occhipinti figured that the 2.72 lb. weight savings was a "tremendous help". Even more important, he added "is the flexibility and confidence this alloy gives us to try new designs without compromising safety or reliability".

While making the drive shafts smaller in diameter, the team also lowered the angle of twist so it would be the same amount for each shaft when torque from the engine was transmitted to the rear wheels. This design modification improved the overall handling of the vehicle.

The improvement in performance and endurance of the vehicle was quite evident, said the team, in competitive events like acceleration, skidpad testing and autocross laps in which the driver puts the racecar under great stress through hairpin turns and tight maneuvering at high speeds.

In the autocross event, the car twists through one tortuous lap in an all-out sprint against the clock. Two drivers in tandem push the car to the limit in the 24-lap endurance event, which lasts about one half hour. The weight savings, observed Chief Engineer Coppola, is vital in the acceleration bursts. The 73 hp engine, fully utilizing a 6-to-1 weight-to-power ratio, propels the racecar from a standing start to 60 mph in four seconds.

The R·I·T team also had upgraded the previous generation of hub assemblies, switching from the 300M high-strength steel to Carpenter's AerMet alloy. These assemblies were connected to the drive shafts on each rear wheel. While the weight savings in this case were modest, the change to AerMet alloy has allowed the team to completely redesign the hubs to optimize their geometry

Two years ago the student design team solved the low-endurance problem by making the spindles entirely from the AerMet alloy, then carried that success into the year 2000 model car.

The R·I·T fabricators has machined the drive shafts, hubs and spindles directly from AerMet alloy bar stock, using state-of-the-art equipment in its modern machine shop. The alloy is an air-hardenable material that is virtually free of distortion when properly heat treated. This was a bonus for the team, who had to make components with complex shapes and critical size tolerances.

Competitive Events

More than 100 schools from the United States, Europe, Asia and Australia participate annually in at least one of the three Formula SAE competitions. Each competitive event consists of one day of technical inspection and three exciting days of static and dynamic events. Teams are judged on how they score in seven different categories, with a value scale assigned to each one:

Engineering Design (15%) - rates the quality of engineering work, design, innovation and knowledge of design concepts; examines test data and analysis Autocross (15%) - drivers must maneuver the car through a tight road course that includes hairpin turns, slaloms, straights and chicanes at the fastest lap time Endurance/Fuel Economy (40%) - tests endurance of both the car and driver over a distance of 22 kilometers. Fuel economy is compared at end of the event, among cars that finish Cost Analysis (10%) - team must prepare a report detailing the cost of manufacturing one vehicle, out of a production run of 1,000 Sales Presentation (7.5%) - team must present the car to a group of hypothetical manufacturers who plan to build 1,000 cars a year for less than $30,000 each Acceleration (7.5%) - tests the car's ability to accelerate from rest over a distance of 75 yards Skid Pad (5%) - evaluates the cornering ability of the car, which must travel at top speed around two loops in a figure eight without displacing any cones

The R·I·T SAE Formula racing team distinguished itself in year 2000 by winning major awards for its race car on three continents. In June, at the SAE event in Detroit, it took home the prestigious Best Engineering Design award, as well as honors for Best Sales Presentation. A month later, at the National Exhibition Centre in Birmingham, UK, the team logged the fastest autocross time of the day and won the title of Best Engineering Design. At this event, head design judge, consultant Carroll Smith, said the car was the best Formula SAE car he had ever seen. R·I·T finished second overall in the inaugural Formula SAE Australasian event in Victoria, Australia. In individual events, the team was first in acceleration, and second in skidpad, autocross, endurance, fuel economy and sales presentation.

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For additional information about Carpenter's AerMet® alloy, contact Bud Carnes by phone at (610) 208-2579, fax (610) 736-8547, e-mail rcarnes@cartech.com. For additional information about the R·I·T race car, contact Michael Occhipinti by phone at (716) 475-7001, fax (716) 475-7002, e-mail formula@rit.edu.