Invisible Helmet (air bag)

On Friday, September 21, 2012 12:41:53 AM UTC-4, James wrote:
On 21/09/12 14:29, Sir Ridesalot wrote:

On Thursday, September 20, 2012 11:05:13 PM UTC-4, Jeff Liebermann

wrote:

http://www.hovding.com/en/how





This has been on this new group in the past I think.



Very interesting that they spent seven years studying actual bicycle

accidents and didbicycle crash tests to determine how the helmet

should be desiined so that it would be effective. Too bad it's only a

single use item though as at $600.00 it's pretty expensive.



How often do you fall off?



I guess pushing the limits you might more often, but personally it's a

long time between spills. Not that I'm interested in wearing a collar.

My impression is that it would get you hot under the collar - so to

speak. I think I'd rather a helmet!



I wonder what happens when you get home, unzip it and throw it on the

bed. Does it sense a crash and "POOF!" ?



--

JS.

I was thinking more along the lines of it having only one impact protection like a foam helmet label often states. What would happen to an airbag type helmet in a sliding crash? Would the helmet tear, deflate and offer no protection? What about a crash where the rider tumbles and strikes the head a couple of times?

This helmet seems to be designed for low speed commuter/cruising use. I can see how this design might become very attractive if the cost per unit dropped substanially.

Whether or not a helmet is needed, when I see images of post-crash cracked or broken helmets I often wonder if there was only the one head strike in the accident.

Many people want inexpensive head protection. Witness the large number of @$30.00 foam helmets in use. Is a $30.00 helmet much less effective than a $300.00 helmet? Some people believe that the more expensive helmets are more likely to break on impact than a cheap helmet because the expensive helmet has less material due to larger or more vent holes in it.

The real issue though is that commuting bicycle riding is not very dangrous.. However, some people do want head protection for just in case - like insurance if you will; hopefully it's never needed but it's there if you do. For those people I bet the idea of an inflatable helmet is very attractive.

Cheers

Jeff Liebermann wrote:
On Fri, 21 Sep 2012 14:41:49 +1000,
wrote:


How often do you fall off?

It only takes one head crash to ruin your day. Weigh the risks
against the odds. If you find the odds in your favor, take your
chances.

For example, if the odds are 10,000:1 of surviving a ride[1], and the
cost of a hospital holiday is about $250,000, the opportunity costs
for a $600 wearable air bag is:
250,000 / 600 = 417:1
Since this is more than the 10,000:1 risks, it doesn't pay to wear
this air bag. However, were the cost of the air bag helmet reduced to
$25, the odds and costs would be the same, and an air bag helmet would
be justified.

I guess pushing the limits you might more often, but personally it's a
long time between spills. Not that I'm interested in wearing a collar.

....

[1] Numbers were conjured out of thin air and do not resemble
reality.

For somewhat more realistic figures, a recent report on the crash data
for London's "Boris Bikes" bike share system said this, in part:

"...in the first year of operation of Cycle Hire there were 7 collisions
involving personal injury per million Cycle Hire bicycle journeys. By
severity of injury, this breaks down as 5 slight and 1 serious injury
collision(s) per million Cycle Hire bicycle journeys."

Note that even the one serious injury was not a fatality. Even in the
chaos of London traffic, your odds on surviving a ride are tremendously
greater than 10,000:1.

BTW, Britain (unlike the U.S.) tries to do a reasonably good job of
measuring the amount of bicycle travel, and thus the number of
fatalities per mile traveled. Year after year, they find that there are
roughly 20 million miles bicycled between fatalities. And Britain isn't
considered a particularly safe cycling country, compared with many.

Bicycling is NOT very dangerous. It does us no good to pretend it is.


--
- Frank Krygowski

Sir Ridesalot wrote:

Is a $30.00 helmet much less effective than a $300.00 helmet? Some
people believe that the more expensive helmets are more likely to break
on impact than a cheap helmet because the expensive helmet has less
material due to larger or more vent holes in it.


The legal situation is that, to qualify for the market, a helmet must
meet impact and other standards. The impact test consists of strapping
the helmet on a magnesium model of a decapitated human head and dropping
it about six feet onto a flat, smooth surface. If the linear
deceleration of the headform is less than 300 gees, the helmet passes
that test. (The drop height is less for the impact surfaces that are
not flat. And yes, there is no crash test dummy; it's just a
decapitated head that gets "protected.")

It's just a pass-fail test, and actual deceleration values are never
reported, AFAIK. So if the designers are trying for a "performance"
helmet, as light as possible, they have an incentive to come as close to
that 300 gees as possible. Any extra protection won't show up in
advertising, but any extra weight will. They can therefore spend much
more time and money whittling down the protection as far as possible
while still just barely passing the test.

OTOH, if the designers are trying for a cheap helmet, they can just make
it bigger, thicker, heavier and less vented, and be sure it will pass
the test on the first try. As a result, cheaper helmets tend to be more
protective. The more you spend for a helmet, the less protection you'll
tend to get.

This has been verified by _Consumer Reports_ magazine several times. CR
has measured deceleration values of decapitated headforms. While they
don't publish the numbers either (nor explain the ludicrously low
certification standards) they have comparatively rated helmets for
impact protection. Sure enough, the cheaper helmets rated much higher
than the expensive ones.

The real issue though is that commuting bicycle riding is not very dangrous.

Exactly. Per mile, it's much safer than walking. We need to stop
pretending it's unusually dangerous to ride a bike.

--
- Frank Krygowski

On Sep 21, 9:27*am, Frank Krygowski
wrote:
Jeff Liebermann wrote:
On Fri, 21 Sep 2012 14:41:49 +1000,
wrote:

How often do you fall off?

It only takes one head crash to ruin your day. *Weigh the risks
against the odds. *If you find the odds in your favor, take your
chances.

For example, if the odds are 10,000:1 of surviving a ride[1], and the
cost of a hospital holiday is about $250,000, the opportunity costs
for a $600 wearable air bag is:
* * 250,000 / 600 = 417:1
Since this is more than the 10,000:1 risks, it doesn't pay to wear
this air bag. *However, were the cost of the air bag helmet reduced to
$25, the odds and costs would be the same, and an air bag helmet would
be justified.

I guess pushing the limits you might more often, but personally it's a
long time between spills. *Not that I'm interested in wearing a collar.

...

[1] *Numbers were conjured out of thin air and do not resemble
reality.


Bicycling is NOT very dangerous. It does us no good to pretend it is.

--
- Frank Krygowski

Frank who are you talking to?
And why do you keep repeating yourself?

But credibility begins at home - if you have none there don't seek it
here.
How many of your friends, club members and family ride without
helmets?
http://bit.ly/PuXqwi

DR

Jeff Liebermann wrote:
-snip risk analysis-

I was sort of counting on the occasional traffic frisson
with negligible damage every ten years or so and then
eventually the fatal ride under a bus rather than the other
choice which is decline deterioration disease and a
lingering death. YMMV.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

frisson ? you could ride over to the cemetery for lunch break. commiserate with those unfortuneates...DUI...DUB...DUM....Panhard....Drum s....Bald Tires....
TFFC....KBDB...

Swedes doahn salt their nroads yaknow....every try that...packing...itslike noguardrails...

- Frank Krygowski


aha a design contest....call SOFTWARE...with prize...most effective at a $100 production level ( from China oc)....every 3 years.

On Friday, September 21, 2012 5:49:36 PM UTC+10, Jeff Liebermann wrote:
On Fri, 21 Sep 2012 16:54:31 +1000, James

wrote:



It only takes one head crash to ruin your day. Weigh the risks

against the odds. If you find the odds in your favor, take your

chances.



For example, if the odds are 10,000:1 of surviving a ride[1], and the

cost of a hospital holiday is about $250,000, the opportunity costs

for a $600 wearable air bag is:

250,000 / 600 = 417:1

Since this is more than the 10,000:1 risks, it doesn't pay to wear

this air bag. However, were the cost of the air bag helmet reduced to

$25, the odds and costs would be the same, and an air bag helmet would

be justified.



Boy, a lot of "tech" analysis to not justify this thing ;-)



Numbers are always impressive, even when they don't mean very much.

Please excuse my baseless fabrication of numbers. It's a bad habit I

picked up from college days. I had a brief part time job working for

an insurance actuary. My job was helping assign dollar values and

costs to various injuries, such as lost limbs. Risk analysis is

fairly simple, if you ignore the intangibles.



The calculations are fairly simple. Start with the average number of

rides per year. Multiply by the sum of the number of years you've

been riding plus the number of years you expect to continue riding.

Divide by the number of accidents, near accidents, close calls, and

anything that might have become an accident. That's your odds.



Using a mythical cycle commuter as an example, if he commutes to work

every day, that's two rides times 365 per year. 50 years is about how

long I would expect one to ride. That's 26,500 rides per lifetime.

The number of accidents and near accidents will vary. I'm a hazard on

anything that moves, and usually manage to have at least one close

call per week. So, I would expect to see

52 * 50 = 2,600

close calls per lifetime, any of which could become a statistic. The

odds of getting (nearly) hurt a

26,500 / 2,600 = 10:1

A more careful rider will do much better.



$250,000 is about what a head injury will cost without insurance.

However, the price range could be wildly variable depending on the

damage. The opportunity cost is:

$250,000 / $600 = 417:1

which is less than the 10:1 lifetime risk of injury. For this bicycle

commuter, the odds favor an expensive air bag helmet.

One day I might follow your reasoning and work some of this out for my situation.

I also note that although I've had a few spills, not once has my helmet shown signs of touching the road.

Yes, $600 is steep, but if you ride lots between falls (low risk of a

fall), and your hair looking good is important to you but you want some

protection in case of a crash, I guess some might consider it. I

wouldn't though, and I doubt the market would be very big.



Hair is not a problem for me since it's slowly falling out. You're

probably correct about the small market. Air bags in cars would not

be very popular if they were not mandatory, mostly due to the cost.

Well, my hair is pretty thin too these days. I keep it very short.

I dunno, in cars they're well hidden. Drivers don't know much about them until - crunch.

I don't recall the last time I crashed and didn't survive ;-)



Head crashes have a tendency to affect the memory. Are you sure you

don't recall your last crash?

Oh, I recall the last time I came off, but I'm fairly sure I'm still alive (hence I survived), and didn't bump my noggin.

And why would you spend $250,000 on hospital holidays if you didn't survive?



Hospitals do not offer a warranty on workmanship. You pay the same

amount whether you live or die. During my last involuntary visit to

the local hospital, I attempted to negotiate a "double or nothing"

deal with the billing office. If I live, I'll pay double. If I die,

I'll owe nothing. They refused. However, I did get half off for

paying cash (mostly in advance).

Nice~!

In a race it is not unheard of to have a crash, pick yourself up and

chase to get back on the bunch.



I don't think this air bag helmet is for racers, where every microgram

is important.

I didn't look how much it weighs, but it would be more aero I would think.

If the air bag exploded, would the

commissaire insist your team car hand you a fresh one before you could

continue?



Of course, especially if he gets a commission from the manufacturer.

The team should carry spares of anything that might fail anyway.



I'm sure there are possibilities. I thought of a bulge behind your head

that doubles as a fairing to improve aerodynamics.



Good idea. However, like all good ideas, I'm sure it will be banned

by the race authorities. That's what happened after a large number of

swim records were broken during the Bejing Olympics. The full body

swim costume worn by Phelps and others were designed to offer

hydrodynamic improvements and better buoyancy.

http://www.thedailybeast.com/articles/2012/07/25/why-ban-full-body-olympics-swimsuits-a-scientist-explains-polyurethane.html



I wonder what happens when you get home, unzip it and throw it on the

bed. Does it sense a crash and "POOF!" ?



Good question. It will cost you $600 to find out.



Learn by destroying? ;-)



Yep. That's how it works. One begins to understand how something

works only after they have broken it (and fixed it). However, I'm

more worried if the air bag helmet has a position sensor. If the

cyclist is somehow placed in an inverted position, as in doing a loop

on a BMX bicycle, will that deploy the air bag?

You'd hope it was more intelligent than that.

[1] Numbers were conjured out of thin air and do not resemble

reality.



C'mon, Jeff. Data, data, data!!!



Sorry. All numbers look about the same after midnight. Much of the

endless discussions on helmet safety revolve around calculating the

risks. There are also different ways of expressing the risks, such as

by the distances traveled. I didn't want to get into the trivial

aspects of the calculations, such as accuracy, so I just fabricated

the numbers. Hopefully, it will not have an effect on my assertions

and allegations.


Oh, crap - I feel a Frank reply coming on...

--
JS.

here's weight weenies

http://weightweenies.starbike.com/li...p?type=helmets

here's the prototype

http://farm1.static.flickr.com/25/58...8285261941.jpg