IndyCar: Kill Switches and Headrests.

Simona De Silvestro raised two interesting points in statements made since last Saturday's crash at Texas.

The first is that the driver activated the on-board fire system. As a reader, I presume that the system functioned as designed. It is not designed to extinguish oil fires that result from oil cooler damage within the sidepod.

That is the job of the first man to the car with a hand-held fire extinguisher. Here (click it) is what that looked like in 2008 at Chicagoland.

That video demonstrates an effective strategy and execution to handle the emergency and protect the driver.

To me, it looks as though the fire is less severe and involves less of the vehicle than was the case in Simona's crash. Perhaps Ed had killed the ignition, or the engine stalled on impact.

Simona stated that her engine was running until the car came to a stop.

This would enable the dry sump oil pump to continue to feed the fire as a result of a broken hose or oil cooler. Hitting the kill switch would have probably helped the situation. Adding an "inertia switch" capability to the vehicle engine management system would help more, and the memo was sent to Randy Bernard Tuesday night.

The Jags I work on have such a device, to disable the fuel injection system and thus kill the engine on impact or rollover. Simona's race car slid for a long time while it was ablaze and still running.

Keeping it simple, the fuel inertia switch as used on the Jaguar road cars would remove the complexity of added signal paths. It's a hands-free kill switch that trips when you crash. Period.

Additional to the "inertia switch" proposal: there is already at least one accelerometer on board an IndyCar to measure g forces on impact. The driver's earpiece records that data and signals the on-board data recorder.

Adding a circuit to communicate this signal to the engine management ECU could accomplish the same goal. Set a signal threshold of perhaps 20 g's to interrupt ignition and fuel injection system power at the ECU. Engineers, doesn't that plan have merit?

Either way, the driver—capable of doing so or not—is not required to hit the kill switch. An IndyCar hit that hard will not be drivable, and there are only bad reasons for the engine to continue to run.

Exactly what is required to expedite removal of the headrest is another lesson to be learned from De Silvestro's crash. If we could hold one in our hands, we could see better ways to make it removable. Without that benefit, here's (click it) a video that shows John Andretti doing just that.

The external master switch is visible at 1:37. The perimeter of the cockpit, without the headrest, is visible at 2:00. The headrest is shown near the conclusion of the video.

At the rear of the headrest, there appear to be two horizontal mounting pins that plug into the chassis, nothing more.

It's not clear to me how the front attachment fastener system is laid out. When installed, Jon Beekhuis tells us that there is a clip that must be removed on each side at the front extensions of the headrest.

Here's another way to handle the installation that expedites removal of the headrest:

Where the headrest mounts in the tub, at the front extensions that John Andretti holds in his hands in the video, that's where I would put the horizontal pins. The pins would be secured to the tub, and mounting holes on the headrest fit over the pins. One clip on each side secures the headrest, same as now.

The pins are as short as possible, to prevent injury. You know what a hood pin looks like? That's the idea. The ends of the headrest, where it mounts on the pins, will now be rounded.

The front pins are now pivot points. 

Then attach the rear of the headrest to the tub, with either one or two vertical mounting pins. Manual removal would mean pulling one or two clips at the base of the airbox, where access is easier from the outside. Then the collar flips forward over the driver's head, pivoting on the front pins.

You have to move the driver's head away from the headrest to get it out of the way. Same as now. The airbox isn't in the way. Release the rear pin, flip the headrest over the driver's head on its front pivots, and it sits on the front cowling. 

Make the rear attachment pins have a manual release at the top (pin clip), and an electrical one at the base, and you have another thing going for you. Think of the release solenoid which opens the trunk latch on your car.

Then you power the latch solenoid with an independent power source: same as the 9V battery that blows the fire bottle, so it is not dependant on operation of the vehicle's electrical system.

Then you activate it the same way, via the master switch. So pulling the master switch ring cuts the vehicle power, blows the fire bottle, and pops the rear headrest latch. The driver or responder flips the headrest over the driver's head, and it's laying out of the way on the nose of the car, front pin clips still in place.

Or, you manually pull the exposed front clips, the extra one or two at the rear, and lift the headrest out the same way as today.

If people are going to tape the headrest to the monocoque, better bring a knife. That's a bad plan, and I believe it is in violation of the stated regulations. Maybe following the rules is all it will take, but there are ways to make it better.

As always, comments are invited. So long as they are about fixing things.