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Design/Research & Development

The role of a Designer is to develop the appearance and body of a car, while also considering engineering, aerodynamics and driver ergonomics. Designers typically have a 4-year degree, either in engineering or design. 

Being a designer is all about creativity, aesthetics, colors, and features, while also taking into consideration how that design will react to physics and forces. 

 

For racing cars, the objectives are much more oriented toward pure performance. The primary objectives of most race cars or performance cars are:
 

  • Maximum acceleration and deceleration

  • Maximum cornering speed

  • Driver/occupant safety

  • Cost of the final product

Here are some of the most important things a designer must take into consideration when building a race car.

Handling

“Handling” is the term used to describe the fundamental behavior of a vehicle being driven. It is often described in terms of the response a car has to driver input. Handling is most often used when describing how the vehicle responds during turns.

For example, how much the car pushes (understeer) in a corner or how loose the car is (oversteer) in a corner.

What is being described is the response of the vehicle from a combination of factors including how the weight is distributed in the car, how the suspension reacts to the driving forces, and how the tires contact the road surface.

By understanding the physics of handling, we can visualize the behavior of the car we are designing or working on to optimize its performance. In our guide below we touch on the various elements that make up car handling.

Suspension

The suspension on a vehicle serves multiple purposes:

  • It provides a stable platform from which to control the vehicle

  • It provides a way to isolate the chassis and driver from the shocking jolts that the tires experience going over anything but a glass-smooth surface.

  • It provides a way to keep all the vehicle’s tires in contact with an uneven surface.

  • It provides damping of oscillations that rubber tires, springs and uneven surfaces naturally create.

Many versions of suspension have been created over time to resolve deficiencies, but in general they all seek to control the movement of the tires in three ways:

  1. Laterally – Controlling side-to-side movement

  2. Longitudinally – Controlling forward/backward movement

  3. Vertically – Controlling up and down movement

Suspensions accomplish this using links and structures that locate the wheels/tires in a specific “geometry” relative to the vehicle. The geometry dictates the behavior the tires/wheel and chassis exhibit when accelerating, braking and turning.

Aerodynamics

Aerodynamics is the science of how air flows around and inside objects. More generally, it can be labeled “Fluid Dynamics” because air is really just a very thin type of fluid.

Above slow speeds, the air flow around and through a vehicle begins to have a more pronounced effect on the acceleration, top speed, fuel efficiency and handling.


Therefore, to build the best possible car we need to understand and optimize how the air flows around and through the body, its openings and its aerodynamic devices.
 

Drag, Drafting, and Downforce
 

No matter how slowly a car is going, it takes some energy to move the car through the air. This energy is used to overcome a force called Drag.
 

Drag, in vehicle aerodynamics, is comprised primarily of three forces:

  1. Frontal pressure, or the effect created by a vehicle body pushing air out of the way.

  2. Rear vacuum, or the effect created by air not being able to fill the hole left by the vehicle body.

  3. Boundary layer, or the effect of friction created by slow moving air at the surface of the vehicle body.
     

Between these three forces, we can describe most of the interactions of the airflow with a vehicle body.

Drafting is a racing technique designed to reduce drag by letting the vehicle in front take on all of the air resistance to gain speed.

In racing, downforce is downward thrust that keeps the vehicle as planted to the road as possible. Vehicle designers and engineers work hand in hand to make the most out of this aerodynamic force to obtain as much grip for the driver as possible. 

Safety

Vehicle safety is the art of protecting the human occupant(s), at whatever cost to the vehicle. The vehicle is expendable, the occupants are not.

Driver and passenger (if any) safety systems consist of multiple layers of protection that are engineered to provide support and protection within and around the cockpit. Depending on the type of vehicle, these systems are composed of different elements but all of them have the same goal—to protect the occupants. Here are a few of the safety features you'll find in a modern day race car.

 

Impact Energy Absorption Structure
 

The first layer of protection for the occupants is the Impact Energy Absorption (IEA) structure. This is the destructible portion of the vehicle that absorbs impact energy from stationary objects (e.g. Walls) and other race or road vehicles. The energy is absorbed or dissipated by the crushing of the structure.

 

Firewall
 

Firewalls protect the occupants from fires within the chassis structure. They create separated areas for the engine and fuel storage so that the occupants are not harmed. They are generally composed of metal and fireproof insulated panels. In addition to direct fire, they provide protection from exhaust gas leaks or potential burn sources, and separate the Occupant Safety cell from high temperature components (engine/exhaust). Example firewalls are shown below in diagram FW1.

 

Occupant Safety Cell / Roll-Bar / Anti-Intrusion
 

The Occupant Safety Cell, or Safety Cell for short, is located within the Impact Energy Absorption (IEA) structure. It effectively surrounds the cockpit of the car. It can be constructed as a spaceframe (tubular structure) or as a monocoque, but in either case it forms a very rigid structure which is not intended to be crushed under the most severe impacts. It is the last line of defense against external objects.

The Safety Cell is also sometimes referred to as the Survival Cell, Roll bar or Roll cage

 

Racing Seat Belts/Harness
 

Racing seat belts or harnesses, like racing seats, are specialized to provide the maximum occupant support in all racing and accident situations. In racing, the harness snugs the occupants against the seat to enhance feel. In accidents, the harness keeps the occupants from moving around the cockpit of the vehicle where they could be seriously hurt by the Safety cell or protrusions.

 

Fuel Safety
 

Fire has been responsible for many deaths and injuries in racing and on roads, and this is due in large part to the use of fuel tanks and lines that weren’t capable of remaining sealed during an impact.

With the advent of the Fuel Safety Cell (also known as a Fuel bladder), fires have become far more rare. These safe fuel tanks usually consist of an outer shell of metal which protects an internal rubber bladder from punctures. Even in extreme impacts the bladder acts like a balloon that is being squeezed—it changes shape, but does not pop.