Re: published helmet research - not troll

Discussion in 'rec.bicycles.soc' started by Frank Krygowski, Jun 17, 2004.

  1. Tom Kunich

    Tom Kunich Guest

    "Steven L. Sheffield" <[email protected]> wrote in message
    news:BD9A40C3.4C306%[email protected]

    Steven, you'll feel a lot better if you finally learn how to use the "ignore
    thread" function.
     


  2. Tom Kunich

    Tom Kunich Guest

    "Bill Z." <[email protected]> wrote in message
    news:[email protected]
    > Frank Krygowski <[email protected]> writes:
    >>
    >> Give us the make and model, Bill, or have the sense to slink away in
    >> embarrassment.

    >
    > It's simply none of your business. I pointed out that it is a typical
    > "teardrop-shaped helmet" with a moderate, but not extreme, number of
    > vents and nothing particularly extreme in its design.


    And yet the most extreme design without vents wasn't as aerodynamic as a
    bald head. Explain how your helmet with vents can be more aerodynamic than a
    V1 Pro.

    Oh, that's right - your proof of that proved just the opposite.
     
  3. Bill Z.

    Bill Z. Guest

    "Steven L. Sheffield" <[email protected]> writes:

    > On 10/18/2004 08:29 PM, in article [email protected], "Bill
    > Z." <[email protected]> wrote:
    >
    > > Frank Krygowski <[email protected]> writes:
    > >
    > >> Bill Z. wrote:
    > >>

    > >
    > > You and two of your minion-trolls are not everyone.

    >
    > Who cares?
    > Now shut up and go away.


    These bozos are posting far more on the topic than I am. Blame
    them.

    --
    My real name backwards: nemuaZ lliB
     
  4. Bill Z.

    Bill Z. Guest

    "Tom Kunich" <[email protected]> writes:

    > "Bill Z." <[email protected]> wrote in message
    > news:[email protected]
    > > Frank Krygowski <[email protected]> writes:
    > >>
    > >> Give us the make and model, Bill, or have the sense to slink away in
    > >> embarrassment.

    > >
    > > It's simply none of your business. I pointed out that it is a typical
    > > "teardrop-shaped helmet" with a moderate, but not extreme, number of
    > > vents and nothing particularly extreme in its design.

    >
    > And yet the most extreme design without vents wasn't as aerodynamic as a
    > bald head. Explain how your helmet with vents can be more aerodynamic than a
    > V1 Pro.


    A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    shape. Is that *really* so hard for you to understand? And a bald
    head is not relevant when you are not going to shave your head in
    any case.

    > Oh, that's right - your proof of that proved just the opposite.


    Nope, and repeating yourself won't make it so.

    --
    My real name backwards: nemuaZ lliB
     
  5. On 10/19/2004 11:54 PM, in article [email protected], "Bill
    Z." <[email protected]> wrote:

    > "Steven L. Sheffield" <[email protected]> writes:
    >
    >> On 10/18/2004 08:29 PM, in article [email protected], "Bill
    >> Z." <[email protected]> wrote:
    >>
    >>> Frank Krygowski <[email protected]> writes:
    >>>
    >>>> Bill Z. wrote:
    >>>>
    >>>
    >>> You and two of your minion-trolls are not everyone.

    >>
    >> Who cares?
    >> Now shut up and go away.

    >
    > These bozos are posting far more on the topic than I am. Blame
    > them.



    And because they post you have to respond? You have this need to get the
    last word in? Isn't that a bit irrational?

    Who cares?
    Now shut up and go away.


    --
    Steven L. Sheffield
    stevens at veloworks dot com
    veloworks at worldnet dot ay tea tee dot net
    bellum pax est libertas servitus est ignoratio vis est
    ess ay ell tea ell ay kay ee sea eye tee why you ti ay aitch
    aitch tee tea pea colon [for word] slash [four ward] slash double-you
    double-yew double-ewe dot veloworks dot com [four word] slash
     
  6. On 10/19/2004 07:59 PM, in article
    [email protected], "Tom Kunich"
    <[email protected]> wrote:

    > "Bill Z." <[email protected]> wrote in message
    > news:[email protected]
    >> Frank Krygowski <[email protected]> writes:
    >>>
    >>> Give us the make and model, Bill, or have the sense to slink away in
    >>> embarrassment.

    >>
    >> It's simply none of your business. I pointed out that it is a typical
    >> "teardrop-shaped helmet" with a moderate, but not extreme, number of
    >> vents and nothing particularly extreme in its design.

    >
    > And yet the most extreme design without vents wasn't as aerodynamic as a
    > bald head. Explain how your helmet with vents can be more aerodynamic than a
    > V1 Pro.
    >
    > Oh, that's right - your proof of that proved just the opposite.
    >
    >




    Who cares?
    Now shut up and go away.


    --
    Steven L. Sheffield
    stevens at veloworks dot com
    veloworks at worldnet dot ay tea tee dot net
    bellum pax est libertas servitus est ignoratio vis est
    ess ay ell tea ell ay kay ee sea eye tee why you ti ay aitch
    aitch tee tea pea colon [for word] slash [four ward] slash double-you
    double-yew double-ewe dot veloworks dot com [four word] slash
     
  7. On 10/20/2004 12:20 AM, in article [email protected], "Bill
    Z." <[email protected]> wrote:

    > "Tom Kunich" <[email protected]> writes:
    >
    >> "Bill Z." <[email protected]> wrote in message
    >> news:[email protected]
    >>> Frank Krygowski <[email protected]> writes:
    >>>>
    >>>> Give us the make and model, Bill, or have the sense to slink away in
    >>>> embarrassment.
    >>>
    >>> It's simply none of your business. I pointed out that it is a typical
    >>> "teardrop-shaped helmet" with a moderate, but not extreme, number of
    >>> vents and nothing particularly extreme in its design.

    >>
    >> And yet the most extreme design without vents wasn't as aerodynamic as a
    >> bald head. Explain how your helmet with vents can be more aerodynamic than a
    >> V1 Pro.

    >
    > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    > shape. Is that *really* so hard for you to understand? And a bald
    > head is not relevant when you are not going to shave your head in
    > any case.
    >
    >> Oh, that's right - your proof of that proved just the opposite.

    >
    > Nope, and repeating yourself won't make it so.





    Who cares?
    Now shut up and go away.


    --
    Steven L. Sheffield
    stevens at veloworks dot com
    veloworks at worldnet dot ay tea tee dot net
    bellum pax est libertas servitus est ignoratio vis est
    ess ay ell tea ell ay kay ee sea eye tee why you ti ay aitch
    aitch tee tea pea colon [for word] slash [four ward] slash double-you
    double-yew double-ewe dot veloworks dot com [four word] slash
     
  8. Bill Z. wrote:
    >
    > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    > shape.


    I know of no ordinary, off-the-shelf helmet that's been shown to have a
    "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    experience measuring aerodynamic drag than you have.

    You could prove me wrong, of course. Just tell us the make and model of
    your helmet, the one you're making these claims for. And point us to
    the drag measurements that you're using to make your conclusion.

    If you won't, it makes it clear that you're just trying to avoid proving
    yourself a liar.

    Unsuccessfully, of course!


    --
    Frank Krygowski [To reply, remove rodent and vegetable dot com.
    Substitute cc dot ysu dot
    edu]
     
  9. Tom Kunich

    Tom Kunich Guest

    "Bill Z." <[email protected]> wrote in message
    news:[email protected]
    > "Tom Kunich" <[email protected]> writes:
    >> And yet the most extreme design without vents wasn't as aerodynamic as a
    >> bald head. Explain how your helmet with vents can be more aerodynamic
    >> than a
    >> V1 Pro.

    >
    > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    > shape. Is that *really* so hard for you to understand? And a bald
    > head is not relevant when you are not going to shave your head in
    > any case.


    1) You haven't a clue what "more aerodynamic" means unless your helmet was
    tested in a wind tunnel. Aerodymanics of low speed laminar flow shapes
    cannot be estimated unless you have hundreds of hours in wind tunnel
    research.

    I have 10's of hours. What about you?

    >> Oh, that's right - your proof of that proved just the opposite.

    >
    > Nope, and repeating yourself won't make it so.


    In case you've missed it, short hair is in. Short hair has a great deal less
    aerodynamic drag than a modern helmet. Modern helmets don't meet the Snell
    Foundation crash standards and perhaps HALF of them do not meet the
    'voluntary' ANSI standards because they are self-certified.

    The fact of the matter is that wearing a helmet makes little if any sense
    but then you'll defend helmets to the death. Hopefully at the hands of a
    defective helmet.
     
  10. Tom Kunich

    Tom Kunich Guest

    "Frank Krygowski" <[email protected]> wrote in message
    news:[email protected]
    > Bill Z. wrote:
    >>
    >> A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    >> shape.

    >
    > I know of no ordinary, off-the-shelf helmet that's been shown to have a
    > "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    > experience measuring aerodynamic drag than you have.
    >
    > You could prove me wrong, of course. Just tell us the make and model of
    > your helmet, the one you're making these claims for. And point us to the
    > drag measurements that you're using to make your conclusion.
    >
    > If you won't, it makes it clear that you're just trying to avoid proving
    > yourself a liar.
    >
    > Unsuccessfully, of course!


    Since a recreational rider spends a great deal of time turning his head this
    way and that to watch traffic, the truth is that teardrop shaped helmet
    carry a significantly higher average drag than a round shape such as the old
    Bell V1 Pro.

    Could it be that is the reason that we're seeing Bell selling round helmets
    again?
     
  11. Tom Kunich

    Tom Kunich Guest

    "Steven L. Sheffield" <[email protected]> wrote in message
    news:BD9BA588.4C51E%[email protected]
    > On 10/19/2004 11:54 PM, in article [email protected],
    > "Bill
    > Z." <[email protected]> wrote:
    >> These bozos are posting far more on the topic than I am. Blame
    >> them.

    >
    > And because they post you have to respond? You have this need to get the
    > last word in? Isn't that a bit irrational?


    Expecting rationality from Zaumen is like expecting cake in a can of beans.
     
  12. Bill Z.

    Bill Z. Guest

    "Tom Kunich" <[email protected]> writes:

    > "Steven L. Sheffield" <[email protected]> wrote in message
    > news:BD9BA588.4C51E%[email protected]
    > > On 10/19/2004 11:54 PM, in article [email protected],
    > > "Bill
    > > Z." <[email protected]> wrote:
    > >> These bozos are posting far more on the topic than I am. Blame
    > >> them.

    > >
    > > And because they post you have to respond? You have this need to get the
    > > last word in? Isn't that a bit irrational?

    >
    > Expecting rationality from Zaumen is like expecting cake in a can of beans.


    Well, Steve, it is interesting that you are blaming me when these other
    guys are posting nothing but a string of baseless personal attacks. And
    that doesn't show anything very complimentary about you. I've every
    justification in telling these guys off given their continued behavior.

    --
    My real name backwards: nemuaZ lliB
     
  13. Bill Z.

    Bill Z. Guest

    Frank Krygowski <[email protected]> writes:

    > Bill Z. wrote:
    > > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    > > shape.

    >
    > I know of no ordinary, off-the-shelf helmet that's been shown to have
    > a "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    > experience measuring aerodynamic drag than you have.


    THen you haven't looked very hard. A V1 Pro was first sold in 1983.
    See <http://www.bellbikehelmets.com/main/about/timeline.html>, which
    BTW has a picture of it. Modern helmets have an assymetric design,
    which fills in the area behind the head. A Bell V1 Pro is
    symmetric or very close - not at all "teardrop" shaped.

    And I doubt if you've measured much of anything - otherwise you'd have
    said what.

    > You could prove me wrong, of course. Just tell us the make and model
    > of your helmet, the one you're making these claims for. And point us
    > to the drag measurements that you're using to make your conclusion.
    >
    > If you won't, it makes it clear that you're just trying to avoid
    > proving yourself a liar.
    >
    > Unsuccessfully, of course!


    Typical of Krygowski's dishonesty - the particular helmet I have is
    a standard design with nothing particularly unique about it, so it
    is not relevant to the discussion. I picked the particular model
    because (a) the shop had it and (b) it fit my head well. There were
    lots of other ones with similar shapes and a similar number of
    vents.

    --
    My real name backwards: nemuaZ lliB
     
  14. Bill Z.

    Bill Z. Guest

    "Tom Kunich" <[email protected]> writes:

    > "Bill Z." <[email protected]> wrote in message
    > news:[email protected]
    > > "Tom Kunich" <[email protected]> writes:
    > >> And yet the most extreme design without vents wasn't as aerodynamic as a
    > >> bald head. Explain how your helmet with vents can be more aerodynamic
    > >> than a
    > >> V1 Pro.

    > >
    > > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    > > shape. Is that *really* so hard for you to understand? And a bald
    > > head is not relevant when you are not going to shave your head in
    > > any case.

    >
    > 1) You haven't a clue what "more aerodynamic" means unless your helmet was
    > tested in a wind tunnel. Aerodymanics of low speed laminar flow shapes
    > cannot be estimated unless you have hundreds of hours in wind tunnel
    > research.
    >
    > I have 10's of hours. What about you?


    Given the number of careers you've claimed to have, Tommy, I really
    don't believe you.

    > In case you've missed it, short hair is in. Short hair has a great deal less
    > aerodynamic drag than a modern helmet. Modern helmets don't meet the Snell
    > Foundation crash standards and perhaps HALF of them do not meet the
    > 'voluntary' ANSI standards because they are self-certified.


    Perhaps you'd care to explain Section 21212(c) of the California
    Vehicle Code which says, "No person shall sell, or offer for sale, for
    use by an operator or passenger of a bicycle, nonmotorized scooter,
    skateboard, or in-line or roller skates any safety helmet which is not
    of a type meeting requirements established by this section." That
    section refers to standards set by the ASTM or the U.S. CPSC. Both
    supercede the ANSI standard which expired in 1994. If you check
    <http://www.bhsi.org/stdcomp.htm>, you'll find that "In May, 1995, the
    ANSI Z90.4 committee voted to adopt the ASTM standard as its own to
    replace the 1984 version, reflecting the movement of active standards
    development to ASTM." <http://www.bhsi.org/cpscfinl.htm> has the CPSC
    standard.

    You can rant all you want, but any helmet sold in California (and I imagine
    most other states) for use on a bicycle has to meet specific standards.

    --
    My real name backwards: nemuaZ lliB
     
  15. Bill Z. wrote:

    > Frank Krygowski <[email protected]> writes:
    >
    > [regarding Bill Zaumen's claim that _his_ helmet is more streamlined than a bare head:]
    >>
    >>I know of no ordinary, off-the-shelf helmet that's been shown to have
    >>a "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    >>experience measuring aerodynamic drag than you have.

    >
    >
    > THen you haven't looked very hard. A V1 Pro was first sold in 1983.
    > See <http://www.bellbikehelmets.com/main/about/timeline.html>, which
    > BTW has a picture of it. Modern helmets have an assymetric design,
    > which fills in the area behind the head.


    If you think the shape of a typical bike helmet allows the airflow to
    smoothly converge behind the helmet, you must know very, very little
    about practical aerodynamics.

    Look again at time trial head fairings or time trial helmets. Those
    shapes are quite extreme - quite long and gently tapered. Why? Because
    that's what it takes to get the airflow to follow the helmet contours to
    a reasonable degree. If the rear of the helmet (or other object) tapers
    too quickly, the boundary layer separates completely and heavy
    turbulence results.

    Modern bike helmets are even worse in this regard. The surface is
    nowhere near smooth, due to the presence of the vents necessary for
    cooling. The air gets stirred up, to the point it wouldn't follow even
    a gentle taper.

    FWIW, I've never seen mention of wind tunnel work aiming to streamline a
    conventional helmet. I assume this is because the designers know such a
    thing is practically impossible.

    But if you want to understand the principles involved, examine the
    fairings used on Human Powered Vehicles - i.e. streamlined bicycles.
    Successful ones are very smooth, long and tapered, and as small as
    possible in frontal area. You won't find one that's shaped like a
    typical bike helmet, which is very rough, _not_ gently tapered, and
    larger than a bare head.

    >>You could prove me wrong, of course. Just tell us the make and model
    >>of your helmet, the one you're making these claims for. And point us
    >>to the drag measurements that you're using to make your conclusion.
    >>
    >>If you won't, it makes it clear that you're just trying to avoid
    >>proving yourself a liar.
    >>
    >>Unsuccessfully, of course!

    >
    >
    > Typical of Krygowski's dishonesty - the particular helmet I have is
    > a standard design with nothing particularly unique about it, so it
    > is not relevant to the discussion.


    If you say _your_ helmet causes less drag than a bare head, I think it's
    relevant to ask what helmet you're talking about!


    --
    Frank Krygowski [To reply, remove rodent and vegetable dot com.
    Substitute cc dot ysu dot
    edu]
     
  16. Bill Z.

    Bill Z. Guest

    Frank Krygowski <[email protected]> writes:

    > Bill Z. wrote:
    >
    > > Frank Krygowski <[email protected]> writes:
    > > [regarding Bill Zaumen's claim that _his_ helmet is more streamlined
    > > than a bare head:]
    > >>
    > >>I know of no ordinary, off-the-shelf helmet that's been shown to have
    > >>a "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    > >>experience measuring aerodynamic drag than you have.

    > > THen you haven't looked very hard. A V1 Pro was first sold in 1983.
    > > See <http://www.bellbikehelmets.com/main/about/timeline.html>, which
    > > BTW has a picture of it. Modern helmets have an assymetric design,
    > > which fills in the area behind the head.

    >
    > If you think the shape of a typical bike helmet allows the airflow to
    > smoothly converge behind the helmet, you must know very, very little
    > about practical aerodynamics.


    It has to reduce drag relative to a completely symmetric helmet, and
    not by very much. BTW, it is well known that you will speed up if
    someone is drafting you - you'll put out more effort than the person
    behind but you'll still go faster than if you were riding alone.
    Filling in the are behind the cyclist (or behind the head) helps.

    > Look again at time trial head fairings or time trial helmets. Those
    > shapes are quite extreme - quite long and gently tapered. Why?


    Because they are *optimized* for the lowest achievable drag. <rest
    of red herring snipped>

    > >>If you won't, it makes it clear that you're just trying to avoid
    > >>proving yourself a liar.
    > >>
    > >>Unsuccessfully, of course!

    > > Typical of Krygowski's dishonesty - the particular helmet I have is
    > > a standard design with nothing particularly unique about it, so it
    > > is not relevant to the discussion.

    >
    > If you say _your_ helmet causes less drag than a bare head, I think
    > it's relevant to ask what helmet you're talking about!
    >


    No it isn't. We were talking about reducing drag relative to a bare
    head for someone with a full head of hair when a Bell V1 Pro causes
    only a very tiny increase in drag over that case. It simply doesn't
    require much of an improvement to get a tiny reduction in drag. The
    particular model I have is not relevant - there's nothing special
    about it.

    --
    My real name backwards: nemuaZ lliB
     
  17. Bill Z. wrote:

    > Frank Krygowski <[email protected]> writes:
    >
    >>
    >>If you think the shape of a typical bike helmet allows the airflow to
    >>smoothly converge behind the helmet, you must know very, very little
    >>about practical aerodynamics.

    >
    >
    > It has to reduce drag relative to a completely symmetric helmet, and
    > not by very much. BTW, it is well known that you will speed up if
    > someone is drafting you - you'll put out more effort than the person
    > behind but you'll still go faster than if you were riding alone.
    > Filling in the are behind the cyclist (or behind the head) helps.


    :)

    Yes, you've just proven conclusively how little you know about practical
    aerodynamics.

    Carry on, Bill. You're fun to watch!

    --
    --------------------+
    Frank Krygowski [To reply, remove rodent and vegetable dot com,
    replace with cc.ysu dot edu]
     
  18. Bill Z.

    Bill Z. Guest

    Frank Krygowski <[email protected]> writes:

    > Bill Z. wrote:
    >
    > > Frank Krygowski <[email protected]> writes:
    > >
    > >>
    > >>If you think the shape of a typical bike helmet allows the airflow to
    > >>smoothly converge behind the helmet, you must know very, very little
    > >>about practical aerodynamics.

    > > It has to reduce drag relative to a completely symmetric helmet, and
    > > not by very much. BTW, it is well known that you will speed up if
    > > someone is drafting you - you'll put out more effort than the person
    > > behind but you'll still go faster than if you were riding alone.
    > > Filling in the are behind the cyclist (or behind the head) helps.

    >
    > Yes, you've just proven conclusively how little you know about
    > practical aerodynamics.


    As opposed to the real thing, I presume. BTW, you might read
    _Bicycle Science_ for a short introduction.

    > Carry on, Bill. You're fun to watch!


    You've proven once again that you'll resort to mindless rhetoric,
    which seems to be all you are capable of. Where you perchance fool
    enough to vote for Bush?

    --
    My real name backwards: nemuaZ lliB
     
  19. Tom Kunich

    Tom Kunich Guest

    "Bill Z." <[email protected]> wrote in message
    news:[email protected]
    > Frank Krygowski <[email protected]> writes:
    >
    >> Bill Z. wrote:
    >> > A V1 Pro has vents. Mine does too, plus having a more aerodyanmic
    >> > shape.

    >>
    >> I know of no ordinary, off-the-shelf helmet that's been shown to have
    >> a "more aerodynamic shape" than a V1 Pro, and I'm sure I've got more
    >> experience measuring aerodynamic drag than you have.

    >
    > THen you haven't looked very hard. A V1 Pro was first sold in 1983.
    > See <http://www.bellbikehelmets.com/main/about/timeline.html>, which
    > BTW has a picture of it. Modern helmets have an assymetric design,
    > which fills in the area behind the head. A Bell V1 Pro is
    > symmetric or very close - not at all "teardrop" shaped.


    Let me guess - you have one of those genetic diseases that cause you to
    forget anything before the last posting?

    It is humorous though to watch someone as ignorant as yourself tell us that
    you can determine areodynamics by having some crude ideas gotten by magazine
    articles on the subject but those with actual wind tunnel experience in the
    speed regimes pertinent have to somehow have published papers on precisely
    the helmet that you're wearing before their opinions are valid. And of
    course you won't actually SAY what your helmet is.

    Is it true that you say "wascuwy wabbit"?

    > Typical of Krygowski's dishonesty - the particular helmet I have is
    > a standard design with nothing particularly unique about it, so it
    > is not relevant to the discussion.


    You're the one claiming that your helmet somehow is more aerodynamic than a
    Bell X1 Pro. We're the one's laughing in your face since you don't have a
    clue what you're talking about. "Teardrop" shaped indeed!

    You real name backwards is "tihs pid"
     
  20. Tom Kunich

    Tom Kunich Guest

    "Bill Z." <[email protected]> wrote in message
    news:[email protected]
    > Frank Krygowski <[email protected]> writes:
    >>
    >> If you think the shape of a typical bike helmet allows the airflow to
    >> smoothly converge behind the helmet, you must know very, very little
    >> about practical aerodynamics.

    >
    > It has to reduce drag relative to a completely symmetric helmet, and
    > not by very much.


    Bill, you really are a nutcase aren't you? You haven't even a rudimentary
    understanding of linear flow aerodynamics and every word from your brain
    makes that more apparent.

    >> If you say _your_ helmet causes less drag than a bare head, I think
    >> it's relevant to ask what helmet you're talking about!
    >>

    >
    > No it isn't.


    Yes it is.

    Your real name backwards is "ssakcaJ"
     
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