Suppose you have to jump out of a 3rd story building window in an emergency.
Would wearing a full face motorcycle helmet before you jump have any effect on your survivability? Or would it not matter at all?
Need answer fast?
Chances are better with a helmet than without, sure.
Sort of depends on how you fall though. Land on your ass and you’ll still break something
What makes motorcycle crashes somewhat survivable is that you usually slow down considerably as you get thrown off the bike and skid along the pavement (your clothes and or skin acting as brake pads) or bounce off objects at oblique angles, etc so you’re not decellerating all at once. Falling off a 3 story building is probably equivelent to hitting a brick wall at 35 or so, which is going to be pretty reliably fatal even with a helmet if you can’t slow before impact. Maybe if there’s some trees you can fall through or an awning or a hill to try to roll down, you could slow your impact to a point that a helmet might help.
Motorcycle helmets are not designed to survive that fall. They are only tested for falls of under 2 meters because most concussive damage typically occurs because the head goes from a meter and a half up to the ground. This is why bicycle helmets are important: the rider’s head starts from higher up than a motorcyclist’s. Good video of the Snell tests on horse riding helmets. Similar tests, same equipment, more explanation. You’ll see that all the tests are gravity-driven.
Don’t land on your head! But if you follow that advice, I cannot see what help a helmet would be.
I would say that it certainly wouldn’t hurt.
Motorcycle helmets have three major advantages . They save the head from direct impact . The round shape allows the head to retain it’s angulation when sliding along the ground,head rather than being wrenched to any of the sides of the head during impact with the road. Finally, the smooth surface of the helmet allows a slow deceleration as the victim skids to a halt rather than a fast deceleration which can come from ordinary road impact .
From the original British report by a neurosurgeon on efficacy of motorcycle helmets during iwartime blackout
Sir Hugh Cairns
If you jump out of a building, how do you plan to land? That’s critical.
3 floors, from middle of 3rd floor, say about 20 feet;
v=sqrt(2gd) =sqrt(2x32x20)=sqrt(1280)=35.8 feet/sec.
Considering 60mph is 88ft/sec, this is not so much lethal as “what part of your body is absorbing the deceleration?”
If the entire weight of your body is stopped by your feet, expect to have not much left for ankles and shins and knees. If your head is doing the stopping, then all a helmet does is transfer that stoppage to the neck vertebrate and the shoulder area bones. Outside of action movies the legs don’t have enough muscluar shock absorber capability to decelerate from that velocity. Land horizontal or close to it, and each part of the body is only stopping its own weight, probably not as damaging. In this case, a helmet may make the difference between an intact skull and one with leakage issues.
Also depends on the landing surface - even a little bit of give, like grass, is probably safer than very hard surfaces like concrete. Also, any irregularities will probably end up causing matching dents or dislocations in the surface of the body.
So short answer - it depends.
Blast and bother, I’m not finding it online, but I did find Lawrence of Arabia, Sir Hugh Cairns, and the Origin of Motorcycle Helmets, demonstrating once again that TE Lawrence is at the center of everything. :eek:
We need a thread discussing him and his role in creating the modern world.
Helmet-wise, I defer to the aptly-named Harry Hurt. He did a later study of bicycle helmets, but I’m not finding it offhand.
A motorcycle helmet would help a little if you land on your head, but even with a helmet, the survivable fall height if you land on your head is ridiculously low. You’d be much better of landing on your feet.