Sportsman saved by helmet. Makes you wonder how light a cycle helmetcould be and still work right.

Sportsman saved by helmet, including wheel running over his head.
http://www.bbc.com/sport/0/formula1/28334565
Makes you wonder how light a cycle helmet could be and still work right.

Andre Jute
Not a weight weenie but...

On Fri, 18 Jul 2014 19:26:34 -0700 (PDT), Andre Jute
wrote:

Sportsman saved by helmet, including wheel running over his head.
http://www.bbc.com/sport/0/formula1/28334565
Makes you wonder how light a cycle helmet could be and still work right.

It wasn't exactly a light bicycle helmet:
http://instagram.com/p/qhtHfdwlPN/

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Saturday, July 19, 2014 6:20:21 PM UTC+1, Jeff Liebermann wrote:
On Fri, 18 Jul 2014 19:26:34 -0700 (PDT), Andre Jute

wrote:



Sportsman saved by helmet, including wheel running over his head.

http://www.bbc.com/sport/0/formula1/28334565

Makes you wonder how light a cycle helmet could be and still work right.



It wasn't exactly a light bicycle helmet:
http://instagram.com/p/qhtHfdwlPN/

I didn't say it was. It is common currency on RBT though that current bicycle helmets could be very much improved. Here's a helmet that saved a guy in a high energy crash. Bicycle incidents on the whole must be less impactful.. So an effective bicycle helmet, while heavier than the present items, would clearly not need to weigh as much as a helmet presented for FIA approval.. The question is, how much would the effective cycle helmet have to weigh to save 50% of cyclists now killed by head injuries in impacts with cars? And, I suspect, a corollary question of some importance to the fashion crowd, how big would it have to be?

Andre Jute

Andre Jute writes:

Sportsman saved by helmet, including wheel running over his head.
http://www.bbc.com/sport/0/formula1/28334565
Makes you wonder how light a cycle helmet could be and still work right.

A wheel didn't run over his head, his car went off the track into a
barrier made of stacked tires. The helmet worked mainly because he was
surrounded by a vehicle and crash cage designed for such impacts.

--
Joe Riel

On Sunday, July 20, 2014 1:27:28 AM UTC+1, JoeRiel wrote:
Andre Jute writes:



Sportsman saved by helmet, including wheel running over his head.

http://www.bbc.com/sport/0/formula1/28334565

Makes you wonder how light a cycle helmet could be and still work right.



A wheel didn't run over his head, his car went off the track into a

barrier made of stacked tires. The helmet worked mainly because he was

surrounded by a vehicle and crash cage designed for such impacts.



--

Joe Riel

Okay, tyres that ran over his head:
"It's exactly the way it came off my head, with the dirt of the day of the accident," Burti, 39, told Brazil's Globo Esporte, adding that the helmet was "very well maintained" and it was possible to see the "marks of the tyres that came over me".
-- from the link already given

On Sat, 19 Jul 2014 16:35:48 -0700 (PDT), Andre Jute
wrote:

On Saturday, July 19, 2014 6:20:21 PM UTC+1, Jeff Liebermann wrote:
On Fri, 18 Jul 2014 19:26:34 -0700 (PDT), Andre Jute
wrote:
Sportsman saved by helmet, including wheel running over his head.
http://www.bbc.com/sport/0/formula1/28334565
Makes you wonder how light a cycle helmet could be and still work right.

It wasn't exactly a light bicycle helmet:
http://instagram.com/p/qhtHfdwlPN/

I didn't say it was.

Sorry. I misread your question.

It is common currency on RBT though that current bicycle helmets could
be very much improved. Here's a helmet that saved a guy in a high
energy crash. Bicycle incidents on the whole must be less impactful.

I'm reading between the lines, but I think the tire rode over the
helmet or glanced off the top. Difficult to tell without more views
of the helmet.

So an effective bicycle helmet, while heavier than the present items,
would clearly not need to weigh as much as a helmet presented for FIA
approval.

It depends on which tests are performed. I would be tempted to offer
a water bag helmet, that provides both cooling and protection. On
impact, the water bags would explode, distributing the force of the
impact over a larger area and redirecting it perpendicular to the
direction of the impact. It might weigh more, but would offer
substantially more protection.

Adding a hard shell might be useful for some types of accidents, but
is not the total answer:
http://www.helmets.org/hardshel.htm

The question is, how much would the effective cycle helmet have to
weigh to save 50% of cyclists now killed by head injuries in impacts
with cars?

That's easy. Just cut the existing bicycle helmet in half down the
center line, and wear half the helmet on half the head. On impact,
half will land on one side or other. Therefore, 50% will die and 50%
will live, thus meeting your specification.

I don't believe any helmet will help in a car crash. The forces
involved are to high. In a race car, the primary protection is the
roll cage, with the helmet providing protection against the head
banging into the roll cage. Take away the roll cage, as in a bicycle,
and the remaining protection is rather limited.

And, I suspect, a corollary question of some importance to the
fashion crowd, how big would it have to be?

The volume of a sphere increases with the cube of the radius.
Therefore, if you double the thickness to double the protection, the
mass increases by a factor of 8. Scaling the thickness upwards will
increase the weight faster than the protection. Even worse, the air
gaps in between the styrofoam battens will need to disappear. While
making the helmet lighter, they tend to make the helmet "buckle" with
a sideways impact. The added weight will probably not be welcome.

I don't know how to design the ultimate bicycle helmet but have some
ideas on how to improve the existing design:
1. Lose the gaps and vents.
2. Water bags with cooling water and partly filled with a
non-Newtonian fluid (corn starch) that hardens on impact.
3. Air bags deployed on impact.
http://www.sheldonbrown.com/airbag-helmet.html
4. Hard shell.
5. Shoulder and neck supports to carry some of the load and impact.
6. Chin guard.
7. Thicker around the ears for added ear protection.
8. Reactive armor (explosion on impact).
9. Electro-rheologic filled bags. Apply DC and they get hard. Can
be used to either fill a cooling air gap between the head and helmet,
or to harden the fluid during impact.
http://en.wikipedia.org/wiki/Electrorheological_fluid



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sunday, July 20, 2014 6:34:10 AM UTC+1, Jeff Liebermann wrote:
On Sat, 19 Jul 2014 16:35:48 -0700 (PDT), Andre Jute

wrote:



On Saturday, July 19, 2014 6:20:21 PM UTC+1, Jeff Liebermann wrote:

On Fri, 18 Jul 2014 19:26:34 -0700 (PDT), Andre Jute

wrote:

Sportsman saved by helmet, including wheel running over his head.

http://www.bbc.com/sport/0/formula1/28334565

Makes you wonder how light a cycle helmet could be and still work right.



It wasn't exactly a light bicycle helmet:

http://instagram.com/p/qhtHfdwlPN/



I didn't say it was.



Sorry. I misread your question.



It is common currency on RBT though that current bicycle helmets could

be very much improved. Here's a helmet that saved a guy in a high

energy crash. Bicycle incidents on the whole must be less impactful.



I'm reading between the lines, but I think the tire rode over the

helmet or glanced off the top. Difficult to tell without more views

of the helmet.

I expect that what he's talking about is the tyres in the barrier he crashed into. They're loose by design, though these days a tarp is thrown over them, and they come flying off and hit things, but by then the energy of the impact is dissipated. All the same, I've been hit by flying tyres a few times and, while we're talking about bruises rather than breakages or concussions, I don't think they would do a bicycle helmet a whole world of good.

So an effective bicycle helmet, while heavier than the present items,
would clearly not need to weigh as much as a helmet presented for FIA
approval.

It depends on which tests are performed. I would be tempted to offer
a water bag helmet, that provides both cooling and protection. On
impact, the water bags would explode, distributing the force of the
impact over a larger area and redirecting it perpendicular to the
direction of the impact. It might weigh more, but would offer
substantially more protection.


Adding a hard shell might be useful for some types of accidents, but
is not the total answer:
http://www.helmets.org/hardshel.htm

The question is, how much would the effective cycle helmet have to
weigh to save 50% of cyclists now killed by head injuries in impacts
with cars?

That's easy. Just cut the existing bicycle helmet in half down the
center line, and wear half the helmet on half the head. On impact,
half will land on one side or other. Therefore, 50% will die and 50%
will live, thus meeting your specification.

Krygo the Kibbitzer will claim that left/right impacts are not a normal distribution. He could be right.

I don't believe any helmet will help in a car crash. The forces
involved are to high. In a race car, the primary protection is the
roll cage, with the helmet providing protection against the head
banging into the roll cage. Take away the roll cage, as in a bicycle,
and the remaining protection is rather limited.

In the Formula One car Burti crashed, the protection is specifically called a "safety cell", and is a fully integrated concept, very strictly regulated and empirically tested for each solution or part-solution.

BMW built a scooter -- I don't know if it was sold to the public or just protos for scooting around paddocks, with two longitudinal roll bars over the rider's head.

And, I suspect, a corollary question of some importance to the
fashion crowd, how big would it have to be?

The volume of a sphere increases with the cube of the radius.
Therefore, if you double the thickness to double the protection, the
mass increases by a factor of 8. Scaling the thickness upwards will
increase the weight faster than the protection. Even worse, the air
gaps in between the styrofoam battens will need to disappear. While
making the helmet lighter, they tend to make the helmet "buckle" with
a sideways impact. The added weight will probably not be welcome.

I don't know how to design the ultimate bicycle helmet but have some
ideas on how to improve the existing design:

1. Lose the gaps and vents.

In some classes of bicycle sport they use helmets that look like pickelhaube, no vents.

2. Water bags with cooling water and partly filled with a
non-Newtonian fluid (corn starch) that hardens on impact.

Water is heavy. There's already a lightweight deformable plastic in military, electronic and cycling applications. The one in my phone's leather case by Tech21 is called D30. It's basically an orange plastic that hardens on impact. It works, in that it has protected my iPhone against being carelessly carried in a shirtpocket from which it falls every time I hurl myself out of my chair.

3. Air bags deployed on impact.
http://www.sheldonbrown.com/airbag-helmet.html

Several versions prototyped around the world, including one that looks like an Elizabethan ruff and is not a "helmet" until set off. I have high hopes of these, because I think part of the resistance against bicycle helmets is inspired by their ridiculously clumsy appearance. You look like an alien bug in the bloody thing.

4. Hard shell.

Heavy.

5. Shoulder and neck supports to carry some of the load and impact.

The HANS has worked wonders in reducing whiplash injuries and deaths in auto racing. But what it basically does, in conjuction with a padded hard hat, as a byproduct of stopping harmful sudden movement, is to immobilize the driver's head so that he cannot turn it or even nod. He can move his eyeball and sip his drink and that's it.

6. Chin guard.

There isn't enough education about doing up current helmets tightly either.

7. Thicker around the ears for added ear protection.

8. Reactive armor (explosion on impact).

See D30 above. Very impressed with that stuff.

9. Electro-rheologic filled bags. Apply DC and they get hard. Can
be used to either fill a cooling air gap between the head and helmet,
or to harden the fluid during impact.
http://en.wikipedia.org/wiki/Electrorheological_fluid
--

Jeff Liebermann

150 Felker St #D http://www.LearnByDestroying.com

Santa Cruz CA 95060 http://802.11junk.com

Skype: JeffLiebermann AE6KS 831-336-2558

An interesting list, not just for technical wonder of what is in it, but for how many solutions or part-solutions already exist -- that cyclists don't want. Basically, what you're telling us, Jeff, is that it isn't a technical problem any more, but has always been a commercial and psychological problem. Either the helmet makers don't want to pay, or the cyclists don't want the solutions, two clearly interrelated matters.

I'm not convinced by another conclusion easily drawn from your list, though I grasp that some of it is given tongue-in-cheek, that a better cycle helmet necessarily needs to be heavier by several multiples. I think the non-Newtonian solution (fluid that hardens on impact, fluid here in a very loose sense as some of these fluids have the same everyday consistency as a draftsman's resettable curve) could be only fractionally heavier.

Andre Jute

nylon cap with ethafoam strips....

On Sunday, July 20, 2014 1:11:20 PM UTC-4, wrote:
nylon cap with ethafoam strips....

.....

MULTI STRETCH POLARTEC WITH ETHAFOAM 'BARRIERS'

On 19/07/14 12:26, Andre Jute wrote:
Sportsman saved by helmet, including wheel running over his head.
http://www.bbc.com/sport/0/formula1/28334565
Makes you wonder how light a cycle helmet could be and still work right.


No. I am not wondering, and I prefer not to find out - ever.

--
JS