Invisible Helmet (air bag)

On 22/09/12 01:09, Sir Ridesalot wrote:
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?

Good points! The material could also be more "grippy" and cause
rotational injuries.

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.

No, I doubt less effective. Probably more effective if anything, but
may be less comfortable (heavier, less ventilation and less flexible
fitting mechanism). Also, the cheaper units are likely more mass
produced and therefore the testing expense is amortised over a larger
number of units. Also the designs don't change much, or get handed down
from last years mid range model, so the design cost has been payed already.

I'm told that all manufacturing runs of helmets that come in to this
country (Australia) must be batch tested. That is, the same design from
two different manufacturing runs must each be tested - to ensure the new
batch isn't somehow less protective. The result is that already
expensive models get even more expensive because the expensive tests are
applied to small numbers and the amortisation doesn't spread that cost
over many units.

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.

I'm sure it will find market.

--
JS

On Fri, 21 Sep 2012 18:32:27 +0700, John B.
wrote:

The auto "air" bags are, I've read, powered by an explosive device. I
assume for some reason such as speed in deployment, or something of
that nature. Would CO2 operate quickly enough?

No. I'm trying to determine why they used helium instead of much
cheaper CO2. The literature claims 0.1 sec inflation. If I did that
with CO2, the plastic airbag cover would freeze (Charles's Law) when
the gas expands. That's why vehicular air bags use explosives instead
of expanding gasses. If they used frozen gasses, getting hit in the
face with a frozen plastic bag will probably break someone's nose.
What I don't know is whether helium really offers a usable advantage.
Because the molecule is smaller than CO2, more helium molecules can
slither through an orifice in less time than the larger CO2 molecule.
http://en.wikipedia.org/wiki/Choked_flow
The term rho is the "real gas density at P and T, kg/m³".
http://www.elmhurst.edu/~chm/vchembook/123Adensitygas.html
He = 0.00018 g/cc
CO2 = 0.00197 g/cc
Yeah, bit difference in flow rate through an orifice.

See above. There are other designs that would also work. One item
not mentioned is that air bags inflate with a loud bang. You don't
want it going boom near your ears.

One of the injuries often mentioned, which the typical cycle helmet
ignores, but which many other sports helmets consider, is a neck
injury. When inflating the air bags, it would have been possible to
inflate a "collar" bag around the neck, thus cushioning any attempt to
bend the neck in an awkward manner.

Perhaps a rocket back pack and ejection seat might be more
interesting. In the even of a sudden acceleration, the rocket
launches the rider up and out of harms way. Yeah, I like that.

--
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 9/23/2012 9:04 PM, Jeff Liebermann wrote:
On Fri, 21 Sep 2012 18:32:27 +0700, John B.
wrote:

The auto "air" bags are, I've read, powered by an explosive device. I
assume for some reason such as speed in deployment, or something of
that nature. Would CO2 operate quickly enough?

No. I'm trying to determine why they used helium instead of much
cheaper CO2. The literature claims 0.1 sec inflation. If I did that
with CO2, the plastic airbag cover would freeze (Charles's Law) when
the gas expands. That's why vehicular air bags use explosives instead
of expanding gasses. If they used frozen gasses, getting hit in the
face with a frozen plastic bag will probably break someone's nose.
What I don't know is whether helium really offers a usable advantage.
Because the molecule is smaller than CO2, more helium molecules can
slither through an orifice in less time than the larger CO2 molecule.
http://en.wikipedia.org/wiki/Choked_flow
The term rho is the "real gas density at P and T, kg/m³".
http://www.elmhurst.edu/~chm/vchembook/123Adensitygas.html
He = 0.00018 g/cc
CO2 = 0.00197 g/cc
Yeah, bit difference in flow rate through an orifice.

See above. There are other designs that would also work. One item
not mentioned is that air bags inflate with a loud bang. You don't
want it going boom near your ears.

One of the injuries often mentioned, which the typical cycle helmet
ignores, but which many other sports helmets consider, is a neck
injury. When inflating the air bags, it would have been possible to
inflate a "collar" bag around the neck, thus cushioning any attempt to
bend the neck in an awkward manner.

Perhaps a rocket back pack and ejection seat might be more
interesting. In the even of a sudden acceleration, the rocket
launches the rider up and out of harms way. Yeah, I like that.



Yeah, what could possibly go wrong?

http://www.rocketcityspacepioneers.c...-stap-sled.jpg

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

On 24/09/12 12:04, Jeff Liebermann wrote:
On Fri, 21 Sep 2012 18:32:27 +0700, John
wrote:

The auto "air" bags are, I've read, powered by an explosive device. I
assume for some reason such as speed in deployment, or something of
that nature. Would CO2 operate quickly enough?

No. I'm trying to determine why they used helium instead of much
cheaper CO2. The literature claims 0.1 sec inflation. If I did that
with CO2, the plastic airbag cover would freeze (Charles's Law) when
the gas expands. That's why vehicular air bags use explosives instead
of expanding gasses. If they used frozen gasses, getting hit in the
face with a frozen plastic bag will probably break someone's nose.
What I don't know is whether helium really offers a usable advantage.
Because the molecule is smaller than CO2, more helium molecules can
slither through an orifice in less time than the larger CO2 molecule.
http://en.wikipedia.org/wiki/Choked_flow
The term rho is the "real gas density at P and T, kg/m³".
http://www.elmhurst.edu/~chm/vchembook/123Adensitygas.html
He = 0.00018 g/cc
CO2 = 0.00197 g/cc
Yeah, bit difference in flow rate through an orifice.

See above. There are other designs that would also work. One item
not mentioned is that air bags inflate with a loud bang. You don't
want it going boom near your ears.

One of the injuries often mentioned, which the typical cycle helmet
ignores, but which many other sports helmets consider, is a neck
injury. When inflating the air bags, it would have been possible to
inflate a "collar" bag around the neck, thus cushioning any attempt to
bend the neck in an awkward manner.

Perhaps a rocket back pack and ejection seat might be more
interesting. In the even of a sudden acceleration, the rocket
launches the rider up and out of harms way. Yeah, I like that.


Interesting, but I'd like to avoid needing to head skyward in case my
'chute doesn't deploy.

I'd like an RF link from my bicycle to a motor car computer such that
when I see a car driver appear to ignore me and fail to give way, I
could press a button to activate _their_ brake as hard as possible,
thereby preventing a collision all together.

Steering control would be nice, in fact if their car computer could
sense their stupidity and take evasive action to save my anxiety, that
would be better still!

Motor vehicles should actively steer away from cyclists, even if that
would be detrimental to other motor vehicles in the vicinity - i.e.
would cause a collision with another motor vehicle.

If impossible to steer far enough away (at least one meter) without
endangering another cyclist (who could be oncoming), the brake should be
applied autonomously to prevent any collision.

--
JS.

On 22/09/12 01:27, Frank Krygowski wrote:

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."

I detect a "typo" in their math. 7 =/= 5 + 1

--
JS

On Sunday, September 23, 2012 10:59:06 PM UTC-4, James wrote:
On 22/09/12 01:27, Frank Krygowski wrote:



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."



I detect a "typo" in their math. 7 =/= 5 + 1

I assumed they meant there was one "moderate" injury, i.e. neither slight nor serious. Admittedly, I don't know how many bins (so to speak) they use in their classification of injuries.

Nonetheless, even if they made a minor and unlikely mistake, it doesn't change the salient point: that cycling, even in London traffic, even by people on unfamiliar bikes who may not normally ride much, is very safe.

- Frank Krygowski

On Mon, 24 Sep 2012 12:17:20 +1000, James
wrote:

On 24/09/12 12:04, Jeff Liebermann wrote:
Perhaps a rocket back pack and ejection seat might be more
interesting. In the even of a sudden acceleration, the rocket
launches the rider up and out of harms way. Yeah, I like that.

Interesting, but I'd like to avoid needing to head skyward in case my
'chute doesn't deploy.

Chute? Oh yeah... I forgot about that. Like the inflatable air bag
helmet, it might be possible to enclose the rider in a large balloon,
and perform a landing like the Opportunity and Spirit landers. Boing.

Steering control would be nice, in fact if their car computer could
sense their stupidity and take evasive action to save my anxiety, that
would be better still!

Is this close enough?
"Subaru EyeSight Overview"
http://www.youtube.com/watch?v=8MMhN9B1Jos
or possibly:
http://machinedesign.com/article/anticollision-radar-uses-lower-frequencies-0821

Back in about 1980, I worked on a proposed 24GHz automobile
anti-collision radar system. It never became even a prototype because
of endless bickering over how it was suppose to operate. One group
wanted it to kill the engine, slam on the brakes, lock the seat
belts, and deploy the air bag in anticipation of an impact. Another
group wanted it to take over steering, braking, and throttle in a
collision avoidance maneuver. Yet another wanted it to act only in an
advisory capacity.

Motor vehicles should actively steer away from cyclists, even if that
would be detrimental to other motor vehicles in the vicinity - i.e.
would cause a collision with another motor vehicle.

Neato. Bumper cars, like in the carnival rides. The auto industry
should like that idea, since it will sell more cars.

If impossible to steer far enough away (at least one meter) without
endangering another cyclist (who could be oncoming), the brake should be
applied autonomously to prevent any collision.

Well, we could just eject the driver. Once the driver is clear of the
vehicle, the vehicle could be made to fly apart (or explode), thus
lessening the impact mass. However, I don't think car buyers would be
interested in a safety feature that also destroys their vehicle.

--
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 Sun, 23 Sep 2012 19:04:34 -0700, Jeff Liebermann
wrote:

On Fri, 21 Sep 2012 18:32:27 +0700, John B.
wrote:

The auto "air" bags are, I've read, powered by an explosive device. I
assume for some reason such as speed in deployment, or something of
that nature. Would CO2 operate quickly enough?

No. I'm trying to determine why they used helium instead of much
cheaper CO2. The literature claims 0.1 sec inflation. If I did that
with CO2, the plastic airbag cover would freeze (Charles's Law) when
the gas expands. That's why vehicular air bags use explosives instead
of expanding gasses. If they used frozen gasses, getting hit in the
face with a frozen plastic bag will probably break someone's nose.
What I don't know is whether helium really offers a usable advantage.
Because the molecule is smaller than CO2, more helium molecules can
slither through an orifice in less time than the larger CO2 molecule.
http://en.wikipedia.org/wiki/Choked_flow
The term rho is the "real gas density at P and T, kg/m³".
http://www.elmhurst.edu/~chm/vchembook/123Adensitygas.html
He = 0.00018 g/cc
CO2 = 0.00197 g/cc
Yeah, bit difference in flow rate through an orifice.

See above. There are other designs that would also work. One item
not mentioned is that air bags inflate with a loud bang. You don't
want it going boom near your ears.

One of the injuries often mentioned, which the typical cycle helmet
ignores, but which many other sports helmets consider, is a neck
injury. When inflating the air bags, it would have been possible to
inflate a "collar" bag around the neck, thus cushioning any attempt to
bend the neck in an awkward manner.

Perhaps a rocket back pack and ejection seat might be more
interesting. In the even of a sudden acceleration, the rocket
launches the rider up and out of harms way. Yeah, I like that.

I wonder. Will this all encompassing inflatable helmet be lighter then
the usual foam hat?

--
Cheers,
John B.

cool


N20 N20 N2O N2O N2O

EYEYYEHAHHAASNORTSBORTSNORTNUHNUHNUHWHOAHEHHEHEHHE HEHE
ahhh that bwas cooll say where's the rear wheel ?