(Note: a version of this article appeared on F1 Fanatic.)
Felipe Massa suffered a fractured skull and a concussion in an accident during qualifying for last weekend’s Hungarian Grand Prix. Rubens Barrichello’s Brawn ejected a coil spring from its rear suspension, and a few seconds later, Massa headbutted the spring at 160 mph. The impact knocked him out and he crashed head-on into a tire wall.
The 800-gram spring didn’t penetrate Massa’s helmet, but it managed to injure him badly anyway. This all coming six days after Henry Surtees, a Formula Two driver, died after being hit in the head by a competitor’s wheel, some are wondering whether cockpit covers might be necessary. (Incidentally, Ayrton Senna, the last person to die in a Formula One car, also died when a wheel hit him in the head.)
But in all the discussion, I haven’t seen any attempts to quantify what happened to Massa. He was hit hard enough to end up in the hospital, and that’s pretty much all we know. So let’s figure it out. How bad is it, exactly, if a spring hits you in the head at 160 mph?
The punch it packs is worse than getting shot. Bullets are deadly because they tear up your insides, but in terms of kinetic energy, most don’t hold a candle to what hit Massa.
Below is a list of kinetic energies of common projectiles. The bullet energies assume point-blank range and were calculated using numbers from Alpine Armoring. All the energies come out of the kinetic energy = 1/2 × mass × velocity2 formula you learned in school.
- 100 mph fastball from Nolan Ryan: 145 joules
- Barry Bonds’s swing (33 oz. bat at 70 mph): 458 joules
- 9mm handgun: 513 joules
- .44 Magnum: 1510 joules
- The spring that hit Massa (800 grams at 160 mph): 2046 joules
- AK-47: 2599 joules
- 12-gauge shotgun slug: 3580 joules
- The wheel that killed Surtees (~12 kg at 120 mph): 17,267 joules
Before we talk about those figures, it’s worth remembering that the Massa and Surtees accidents were real-world situations, so our numbers are imprecise. Massa was moving at 160 mph, but if the spring was traveling in the same direction as his Ferrari, or if it ricocheted off of his car before striking him, the estimate of 2046 joules may be too high. If, for instance, we change the spring’s collision speed to 120 mph, its kinetic energy drops about 44% to 1151 joules. The same caveats apply to the figures on Surtees’s accident.
With that out of the way, let’s put the numbers into perspective. Bullets focus their energy on a tiny area, which is why they would penetrate, say, a driver’s helmet. So let’s look at the baseball examples, since the contact patch in those cases is more similar to being hit with a coil spring.
Massa would have been 14 times better off getting beaned by Nolan Ryan. He would have been four times better off letting Barry Bonds take a full-force swing at his head. For that matter, in terms of sheer energy, he’d have been better off letting Barry Bonds hit him in the head at the same instant that someone shot him point-blank with Dirty Harry’s gun.
It’s incredible that a helmet can turn that into a survivable injury, but even so, the massive energy of Surtees’s accident is a reminder that there’s a limit to the protection that two inches of padding can offer. Being hit in the head with a wheel moving at race speeds is easily deadly, helmet or not.
If the same thing causes another death — the first since Senna’s — in F1, the result may well be a rush to implement closed cockpits. And if that day should come, let’s not pretend to have learned something we didn’t already know today. Cockpit covers may or may not make sense, but if we are against them now, we shouldn’t be waiting for a death to change our minds.
The bottom line is that we need a way to calculate the spring’s closing speed. Watching the video frame by frame, we see that the spring takes roughly one frame to cover the distance from the front of Massa’s car to his helmet. Judging by pictures of his Ferrari, that distance is very close to half the length of the car. Figures on the length of the F60 are difficult to come by, but for all the recent F1 cars whose lengths I did find, the answer hovered around 180 inches.
So the spring traveled about 90 inches, or 7.5 feet, in one frame. PAL video uses a frame rate of 25 frames per second, so 7.5 feet per frame translates to 187.5 feet per second. That’s 127.8 mph. Convert everything to kilograms and meters per second, plug it into KE = 1/2 mv2, and the spring’s kinetic energy comes out to 1306 joules.