Vehicle Safety Basics, How-To & Design Tips cont…
Fuel, Lubricants and Coolant Safety
Although considerable attention is paid to keeping occupants safe in their own car, there are safety considerations that also prevent injury to other vehicles’ drivers/occupants. Fuel, lubricant and coolant safety falls into this category.
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.
Fill valves can be used to ensure the contents of the tank are normally prevented from coming back out through the fill tube. The bladder also contains foam which prevents fuel from sloshing around causing unwanted weight transfer and fuel starvation problems.
Fuel safety cell placement is also important. Placing the cell at the CG will give a balanced CG no matter what the fuel load. However it may not be possible to do so, so at the very least you should attempt to keep it from being too far from the CG to prevent a changing polar moment of inertia. It is also worth considering having it physically separated from the occupants by a firewall.
Fuel lines follow a similar design. An armored shell which prevents cuts surrounds a flexible line. Routing of fuel lines should also be considered to avoid placing them in locations where they are more likely to be damaged (i.e. The outer structures of a chassis or where objects are likely to move nearby)
Lubricant and Coolant Safety
When lubricants like engine oil and coolant drop onto the road surface, they create a hazard for other vehicles. In racing, it is worth considering a catch mechanism under the engine to prevent spills and many sanctioning bodies require catch and overflow containers for lubricants and coolants.
Driveline components pose a significant threat both to the vehicle which loses them and to other vehicles.
Shaft Safety Loops
For vehicles with front engine/rear drive or four wheel drive, shaft safety loops are important to prevent a broken propeller shaft (The shaft which runs between the front and rear of the vehicle) from dropping to the road surface and causing a pole vault effect or damage to the underside of the vehicle.
Racing Wheel Tethers
Wheel tethers were introduced to prevent a broken suspension with a wheel and tire attached from leaving the race vehicle. Because of their inertia and propensity to bounce, this combination poses a serious threat to both racers and spectators.
The tether is usually composed of braided steel or synthetic fibers with one end attached to the chassis and the other to the upright/knuckle. This safety feature could have significant value in all racing series, but especially open wheel racing where suspension breakages in crashes are very frequent.
Safety Tips (3/3)
Keep the fuel safety cell and battery away from the driver and danger
Use a sealed firewall between the fuel safety cell and driver and place the fuel safety cell inside the chassis away from areas likely to be crushed in an impact. Encasing the battery in a sheet metal box container can also prevent punctures and acid leaks.
Don’t scrimp on safety
Use only top quality certified suppliers of safety equipment. The costs are usually higher, but consider how much you value your life. Fuel safety cells (Sanctioning body certified), seat belts (5 or 6 point sanctioning body certified only!), and driver safety wear (Nomex) are important in race vehicle types where they are appropriate. The quality of road car safety devices should also be a top priority.
Recommended Further Reading
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