Erg Testing and Drag Factor

Erg Testing and Drag Factor

Post by Kieran Anthony Coghla » Tue, 26 Nov 1996 04:00:00


Okay, just to set my tone so as not to incur any misunderstandings:  I am
*humbly* asking a question, i.e. I _am not sure_ of the answer and am not
saying anyone is wrong or uninformed.  If anyone is uninformed on this,
it's me.  Now, my question:

I didn't think there were any restrictions on damper settings for erg
tests/competitions.  I have been to four local indoor regattas (i.e.
qualifiers for CRASH-B) over the past few years, and the only rule was
that what ever damper setting you chose, you were stuck with.  Meaning you
couldn't change the setting during the race.  Have the rules changed?  If
they have, I think they should be changed back to the "no restriction"
state.  After all, CII claims that it doesn't matter what the setting is.
In other words, Concept II says that the guy who pulls a 6 minute 2km with
the damper set at 8 spent the exact same amount of energy as the guy who
pulled a 6 minute 2km with the damper set at 4.  (Reference this data from
a thread that occured here in '95, where C2 actually responded with a
post.  Some may recall the thread was started with the concern of
"drafting" on model B's when ergs were set too close to one another during
a peice.  The physics police were drawing *** with each other, until C2
stepped in.)

-Kieran Coghlan
UC Irvine alumnus.

Quote:

> Here's an idea: why not prescribe a DRAG FACTOR for the Testing
> Protocol, instead of the usual fan setting?  Would this not be a more
> accurate way of setting a standard of measure for testing, as each erg
> is slightly different (ie, fan settings on different ergs correspond to
> **different** DRAG FACTORS on those ergs).

> Another idea: remove any and all restictions on DRAG FACTOR and/or fan
> settings, or *reevaluate* them.  Lightweights do not row with rigs set
> for heavyweight because of weight, etc (eg, 160cm spread w/ 88.5 cm
> inboard, 290 overall--lights vs 159 spread, 88 cm, w/ 292
> overall--hvys).
> Should the same "rigging theories" used on the water be applied to the
> erg as well?  Reevaluation of the current protocol with this
> consideration may prove for interesting results.

> Just a thought.  Or two.

 
 
 

Erg Testing and Drag Factor

Post by Simpson & Associate » Wed, 27 Nov 1996 04:00:00

Here's an idea: why not prescribe a DRAG FACTOR for the Testing
Protocol, instead of the usual fan setting?  Would this not be a more
accurate way of setting a standard of measure for testing, as each erg
is slightly different (ie, fan settings on different ergs correspond to
**different** DRAG FACTORS on those ergs).

Another idea: remove any and all restictions on DRAG FACTOR and/or fan
settings, or *reevaluate* them.  Lightweights do not row with rigs set
for heavyweight because of weight, etc (eg, 160cm spread w/ 88.5 cm
inboard, 290 overall--lights vs 159 spread, 88 cm, w/ 292
overall--hvys).
Should the same "rigging theories" used on the water be applied to the
erg as well?  Reevaluation of the current protocol with this
consideration may prove for interesting results.

Just a thought.  Or two.

 
 
 

Erg Testing and Drag Factor

Post by Simpson & Associate » Wed, 27 Nov 1996 04:00:00

Testing Protocol is prescribed for National Team Testing, not indoor
regattas.

 
 
 

Erg Testing and Drag Factor

Post by Walter Martinda » Thu, 28 Nov 1996 04:00:00


Quote:

>Okay, just to set my tone so as not to incur any misunderstandings:  I am
>*humbly* asking a question, i.e. I _am not sure_ of the answer and am not
>saying anyone is wrong or uninformed.  If anyone is uninformed on this,
>it's me.  Now, my question:

>I didn't think there were any restrictions on damper settings for erg
>tests/competitions.  I have been to four local indoor regattas (i.e.
>qualifiers for CRASH-B) over the past few years, and the only rule was
>that what ever damper setting you chose, you were stuck with.  Meaning you
>couldn't change the setting during the race.  Have the rules changed?  If
>they have, I think they should be changed back to the "no restriction"
>state.  After all, CII claims that it doesn't matter what the setting is.
>In other words, Concept II says that the guy who pulls a 6 minute 2km with
>the damper set at 8 spent the exact same amount of energy as the guy who
>pulled a 6 minute 2km with the damper set at 4.  (Reference this data from
>a thread that occured here in '95, where C2 actually responded with a
>post.  Some may recall the thread was started with the concern of
>"drafting" on model B's when ergs were set too close to one another during
>a peice.  The physics police were drawing *** with each other, until C2
>stepped in.)

>-Kieran Coghlan
>UC Irvine alumnus.


>> Here's an idea: why not prescribe a DRAG FACTOR for the Testing
>> Protocol, instead of the usual fan setting?  Would this not be a more
>> accurate way of setting a standard of measure for testing, as each erg
>> is slightly different (ie, fan settings on different ergs correspond to
>> **different** DRAG FACTORS on those ergs).

>> Another idea: remove any and all restictions on DRAG FACTOR and/or fan
>> settings, or *reevaluate* them.  Lightweights do not row with rigs set
>> for heavyweight because of weight, etc (eg, 160cm spread w/ 88.5 cm
>> inboard, 290 overall--lights vs 159 spread, 88 cm, w/ 292
>> overall--hvys).
>> Should the same "rigging theories" used on the water be applied to the
>> erg as well?  Reevaluation of the current protocol with this
>> consideration may prove for interesting results.

>> Just a thought.  Or two.

FWIW, Canadian national team ergometer testing is as follows: Model B, all
use large sprocket, vents closed.  Model C, Men test on "3", Women test
on "2".  This holds for the 20 min tests and for the 2000 m tests.
 
 
 

Erg Testing and Drag Factor

Post by Jim Kreuzige » Thu, 28 Nov 1996 04:00:00

Quote:

  (deleted)

> After all, CII claims that it doesn't matter what the setting is.
> In other words, Concept II says that the guy who pulls a 6 minute 2km with
> the damper set at 8 spent the exact same amount of energy as the guy who
> pulled a 6 minute 2km with the damper set at 4.  (Reference this data from
> a thread that occured here in '95, where C2 actually responded with a
> post.  Some may recall the thread was started with the concern of
> "drafting" on model B's when ergs were set too close to one another during
> a peice.  The physics police were drawing *** with each other, until C2
> stepped in.)

> -Kieran Coghlan
> UC Irvine alumnus.

I am including with this post a copy of the response that I received
from the Concept II people regarding the "drafting question" that
my former teammate mentioned above.  My original question was posted
a couple of years ago and addressed the effects of placing two or more
Model B ergs too close during erg pieces.  My teammates and I noticed
that ergs placed too close together would cause some sort of "drafting",
where some ergs would seem "easier" (lighter load) and others "harder"
(heavier load).  We were wondering if anybody had done any actual testing
of our perceived effect.  The physics police (a much smaller group in
those days) did have a rousing debate on the subject.  It was then
that I received the e-mail from Concept II explaining their test and
exactly how the PM1 and PM2 calculates drag factors.

The below message can also be found at the Georgia Tech Crew Home Page
(http://SportToday.org/).    

--Jim
___________________________________________________________
Jim Kreuziger                           Lottery: A tax on
Jet Propulsion Laboratory               people who are bad
phone:  (818) 306-6041 work             at math.

___________________________________________________________

It is true that multiple ergs used near each other can effect the drag
factor in a similar way that the damper effects the drag factor.  This
effect was significant for the Model A, noticeable in some situations
in the Model B, and we have yet to find a noticeable effect no matter
how close in the Model C.  Note that the Model A moves a tremendous
amount of air compared to the Model C.  The new performance monitor
(pm2) has the ability to display this drag factor.  Hold down the
ready button and press rest before you begin rowing and the drag
factor will appear in the lower right hand box.  With this you can
see exactly what happens when some else begins to row next to you.

We tried this a few days ago and found very little change in drag
factor less than 1% with two Model B ergs at 4 foot spacing.  However, at 3 feet
the drag factor was lowered by about 20% when an adjacent erg started
up.  With the Model C erg we found very little change less than 1% at 2.5 feet.
At 2.5 feet there was no more elbow room.  As a point of reference the
full scale of 1 to 10 on the Model C damper represents more than 100%
change in drag factor.

Most important, how does this all effect final erg scores?  The pm1
does not handle changes in the drag factor quickly because it uses
the average of the last 16 drag factors to do its calculation.
That is why when you shut the damper during a piece
you will not only feel a light load but your pace temporarily improves
as well.  You will then have a real but gradually reducing benefit
over the next 16 strokes until all the old drag factors are out of
the 16 stroke average.  This is why moving the damper is not allowed
during a race.  Actually, the benefit is not as good as may seem.
Take the case of two Model B ergs at 3 feet spacing.  You are doing
at 2500m piece at 1:40 pace.  Someone gets on the erg next to you are
euphoric!  You get an instant 20% power benefit which decreases
over the next 16 strokes giving you a 1 second faster time over
the 2500m.

The pm2 has a much more powerful processor (the pm1 is 10 years old)
and can calculate the drag factor more accurately so as not to need
the averaging.  Therefore, it responds right away to any change in
drag factor so the pace values are rapidly corrected as conditions
change.  There is still the issue of what loading is biomechanically,
physiologically, and psychologically most efficient for any given
individual.

Dick Dreissigacker - Concept II

 
 
 

Erg Testing and Drag Factor

Post by Kieran Anthony Coghla » Thu, 28 Nov 1996 04:00:00

Quote:

> FWIW, Canadian national team ergometer testing is as follows: Model B, all
> use large sprocket, vents closed.  Model C, Men test on "3", Women test
> on "2".  This holds for the 20 min tests and for the 2000 m tests.

3 and 2 !?!?  Wow.  I was just informed that here in the US, it's 6 or 7
for the men and 4 or 5 for the women.  That's a pretty big difference...

-Kieran Coghlan
UC Irvine alumnus.

 
 
 

Erg Testing and Drag Factor

Post by Demon Rowe » Thu, 28 Nov 1996 04:00:00

I placed an erg on the water and it
sank to the bottom

Now that's drag factor!!!!!

hahahahaha!!!!!!!!!!!!!!!!!!!!!!!!!

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