What is the cause of most aviation accidents:
Usually it is because someone does too much too soon, followed very quickly by too little too late.
— Steve Wilson, NTSB investigator
It's something we don't like to think about too much. Crashing. But sometimes it happens. Mechanical failure, driver error, attempting to avoid someone elses error, pushing that little bit too hard - there are plenty of things that can lead to a crash, and once the trigger has happened, it's too late to be worrying about whether all the right protections are in place. They need to be complete before the car ever turns a wheel in anger.
So, in this article we're not going to be looking at what you can do to avoid having a crash (the doing "too much too soon" from the quote at the top), rather we'll look at what you can do to your racecar in advance to ensure that if you ever do end up in that situation you're not left with the second part of the quote: "too little too late".
It's not possible to make your car "crash proof", but it is possible to apply the maximum amount of thought, effort and preparation to provide yourself the maximum chance of survival, and minimum chance of injury.
The aviation world are the accepted experts when it comes to crashworthiness. And they define crashworthiness as follows:
The ability of an aircraft and its internal systems to protect occupants from injury in the event of a crash.
Substitute the word aircraft for racecar, and this sounds a lot like something we might want to achieve.
So, what are the principles and how do they apply to us?
The aviation industry uses an acronym to describe the specific areas for attention when assessing/improving crashworthiness. The acronym is CREEP.
C - Container
R - Restraint
E - Energy absorption
E - Environment (local)
P - Postcrash factors
That's great, but how do these apply to us?
The container in an aircraft is the cockpit and cabin area - the space where people go. For us, it's the cockpit, or passenger cell.
Ideally the container will form a protective shell around the occupant(s) in the event of a crash. It should be strong, and protect as many sides as possible. The container needs to protect the occupant from external objects penetrating the skin, and also from other parts of the vehicle entering the cabin.
To improve the integrity of the container, racecars are often seam welded, strengthening panels may be added to parts of the skin. The rollcage is a very important feature of our container. Other things you can do is race with your windows up, and fit and use window nets. Some racecars feature side impact protection, in the form of carbon fibre slabs mounted to the side of the driver.
Obviously restraint refers to any system or device which keeps the occupant(s) in position. This is desirable to avoid the occupant contacting parts of the inside of the container, or being ejected altogether.
In a racecar, the restraint must be strong. The stronger and wider the webbing of your multi-point harness, the more chance the harness has of keeping you in place. One sometimes overlooked part of the restraint is its mounting - the mounts must be strong, and not allow the restraint to come loose under impact conditions.
The basic lap-strap stops the midsection from moving forward. Shoulder straps stop the upper body from moving forward (or to the side), and crotch straps reduce the chance of 'submarining'.
A HANS device can be considered as an addition to the restraint system, and stops the head and neck being overextended, and greatly reduces the likelihood of neck injuries.
Window nets are another aspect of restraint (and crossover to the container section). Some cars also feature small straps connected to the arms to minimise the chance of flailing (sometimes seen in use in Sprintcars).
This refers to the ability of the vehicle to absorb some of the impact energy to reduce the impact loading on the occupant. The more absorption, the more time is available for deceleration, and the less force is applied to the occupant.
This can be seen vividly in the video above. The 'crumple-zones' of the late model car provide more time for the deceleration to occur, and the forces on the occupant are greatly reduced.
In our racecar, there is not a lot that can be done to improve energy absorption, it is inherited from the vehicle manufacturer. We can ensure that our car is correctly assembled and that all parts are in good repair (no rust!).
This means the area in the cabin around the occupants. Obviously you would not install sharp knives pointing at the driver so in an impact he has nowhere to go but to the knives.
Crashworthiness looks at all objects within reach of the occupant in a crash scenario - with restraints at full extension, and extremities (arms and legs) flailing. Sharp edges, switches, steering wheels are some common local environment hazards.
Have a good look at the cockpit of your car, and see if there is anything you would be happy to slam your hand against at full force, anywhere in reach of your arms, legs and head. If you find something, look at if it may be able to be relocated or 'de-lethalized' - put a foam cover over it, or otherwise reduce the consequence of an impact.
This is what happens to the vehicle in the aftermath of a crash. Does fuel keep pumping through the fuel lines? Do the petrol/oil/lubricant tanks rupture and leak? Common postcrash hazards are: fire, fumes, fuel, oil and water.
The ideal scenario is to control these hazards at their source. In a racecar, a crash resistant fuel cell is much less likely to allow fuel out to start a fire. An automatic fuel pump cutoff will stop pumping fuel to the hot engine bay. A manual isolation switch will stop everything (if someone is able to activate it). Second best is dealing with the subsequent problem: extinguishing the fire, wearing flameproof nomex clothing etc.
There are many things we can do to help with postcrash factors including: fitting the best systems - fuel cell, fuel pump cutoff, leakproof catch tanks and reservoirs; wearing the best safety gear - nomex overalls and underwear; providing first aid equipment - serviceable fire extinguisher and manual cutoff switch.
The final part of postcrash factors is getting safely out of the vehicle. The restraint system must be easily released, and the doors must be easy to open and egress through. You should regularly familiarise yourself with escaping your racecar - try to imagine it is on fire, close your eyes, and practice getting out. It may save your life.
So, hopefully we never need to use this stuff. But, if we ever do, time spent thinking about, and addressing it now, may be enough to save your life, and you won't be relying on 'too little too late'.