Why use Watts on Ergs???

paul_v_smith@hotmail.com

10-07-2008, 04:11 PM

On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
>
> > Question posted by a surf boat rower on their newsgroup for you guys
> > to help answer!
> > (A sweep is the surf boats semi equivalent of a coxswain but at least
> > twice the weight as they use their body weight to steer the boat down
> > waves- also often the coach of the crew).
>
> > >It may be a silly question but how is the Watt's score on a concept ergo derived?
> > >I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
> > >To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
> > >Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
>
> It's the average power output through the stroke (and recovery).
>
> If you're doing several pieces stepping up the work, then it's
> probably better to step up watts than split (or at least be aware that
> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> between the second and third pieces than first and second; and you'll
> feel it). If you care about being very accurately on a pace, watts is
> better: there's a fair bit of difference between 1:50.0 and 1:50.9
> split, but both will just show up as '1:50' on the monitor.
>
> Pete

Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
correct about the Avg power per stroke cycle. But how many
consecutive strokes will show the exact same displayed pace anyhow?
My PR is 37 while trying, but it's more like 8-10 during any regular
session before a faster or slower pace is displayed for at least 1
stroke. Using Watts is a good way to divert yourself from being
obsessed with a particular pace, but Cal/hr would serve the same
purpose for that. The PM speaks several languages, pick the one you
like and go with it. [:o)

If you want your pace displayed to one decimal place you can always go
with ErgMonitor (tm). EM also shows Watts without having to change
screen modes, plus a bunch of other stuff. (slight understatement)
LOL

- Paul Smith

James Elder

10-07-2008, 04:38 PM

> >It may be a silly question but how is the Watt's score on a concept ergo derived?

I have known coaches who like to use watts to calculate an extreme
form of weight adjustment as a selection aid for crews where all
athletes are at a similar weight i.e. lightweights:

e.g. Measure watts/kg for a 2k test.

10-07-2008, 04:56 PM

paul_v_smith@hotmail.com wrote:
> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
>>
>>> Question posted by a surf boat rower on their newsgroup for you guys
>>> to help answer!
>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
>>> twice the weight as they use their body weight to steer the boat down
>>> waves- also often the coach of the crew).
>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
>> It's the average power output through the stroke (and recovery).
>>
>> If you're doing several pieces stepping up the work, then it's
>> probably better to step up watts than split (or at least be aware that
>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
>> between the second and third pieces than first and second; and you'll
>> feel it). If you care about being very accurately on a pace, watts is
>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
>> split, but both will just show up as '1:50' on the monitor.
>>
>> Pete
>
> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> correct about the Avg power per stroke cycle. But how many
> consecutive strokes will show the exact same displayed pace anyhow?
> My PR is 37 while trying, but it's more like 8-10 during any regular
> session before a faster or slower pace is displayed for at least 1
> stroke. Using Watts is a good way to divert yourself from being
> obsessed with a particular pace, but Cal/hr would serve the same
> purpose for that. The PM speaks several languages, pick the one you
> like and go with it. [:o)
>
> If you want your pace displayed to one decimal place you can always go
> with ErgMonitor (tm). EM also shows Watts without having to change
> screen modes, plus a bunch of other stuff. (slight understatement)
> LOL
>
> - Paul Smith

Just curious (not a jab, honestly) did you ever figure out how EM's
instantaneous power numbers are calculated (i.e. each power data point
on one of the power curves)? They don't equal handle force x handle
velocity, so I've been curious what the numbers do equal (i.e. what do
they mean).

-KC

paul_v_smith@hotmail.com

10-07-2008, 07:07 PM

On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
> paul_v_sm...@hotmail.com wrote:
> > On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> >> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
>
> >>> Question posted by a surf boat rower on their newsgroup for you guys
> >>> to help answer!
> >>> (A sweep is the surf boats semi equivalent of a coxswain but at least
> >>> twice the weight as they use their body weight to steer the boat down
> >>> waves- also often the coach of the crew).
> >>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
> >>>> I know Watts are joules per second, so is the watt's score the totaljoules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
> >>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
> >>>> Just trying to get my head around it because I prefer to have it seton time/500m and my >sweep prefers me to have it on Watts for some drills.
> >> It's the average power output through the stroke (and recovery).
>
> >> If you're doing several pieces stepping up the work, then it's
> >> probably better to step up watts than split (or at least be aware that
> >> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> >> between the second and third pieces than first and second; and you'll
> >> feel it). If you care about being very accurately on a pace, watts is
> >> better: there's a fair bit of difference between 1:50.0 and 1:50.9
> >> split, but both will just show up as '1:50' on the monitor.
>
> >> Pete
>
> > Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> > correct about the Avg power per stroke cycle. But how many
> > consecutive strokes will show the exact same displayed pace anyhow?
> > My PR is 37 while trying, but it's more like 8-10 during any regular
> > session before a faster or slower pace is displayed for at least 1
> > stroke. Using Watts is a good way to divert yourself from being
> > obsessed with a particular pace, but Cal/hr would serve the same
> > purpose for that. The PM speaks several languages, pick the one you
> > like and go with it. [:o)
>
> > If you want your pace displayed to one decimal place you can always go
> > with ErgMonitor (tm). EM also shows Watts without having to change
> > screen modes, plus a bunch of other stuff. (slight understatement)
> > LOL
>
> > - Paul Smith
>
> Just curious (not a jab, honestly) did you ever figure out how EM's
> instantaneous power numbers are calculated (i.e. each power data point
> on one of the power curves)? They don't equal handle force x handle
> velocity, so I've been curious what the numbers do equal (i.e. what do
> they mean).
>
> -KC

Magic. That's why the Pace works out to be so close to the PM.

Sorry, I can't take you seriously after learning how you perceive your
dogs level of intelligence.

Jab away.

- Paul Smith

10-08-2008, 01:28 AM

paul_v_smith@hotmail.com wrote:
> On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
>> paul_v_sm...@hotmail.com wrote:
>>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
>>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
>>>>> Question posted by a surf boat rower on their newsgroup for you guys
>>>>> to help answer!
>>>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
>>>>> twice the weight as they use their body weight to steer the boat down
>>>>> waves- also often the coach of the crew).
>>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
>>>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
>>>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
>>>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
>>>> It's the average power output through the stroke (and recovery).
>>>> If you're doing several pieces stepping up the work, then it's
>>>> probably better to step up watts than split (or at least be aware that
>>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
>>>> between the second and third pieces than first and second; and you'll
>>>> feel it). If you care about being very accurately on a pace, watts is
>>>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
>>>> split, but both will just show up as '1:50' on the monitor.
>>>> Pete
>>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
>>> correct about the Avg power per stroke cycle. But how many
>>> consecutive strokes will show the exact same displayed pace anyhow?
>>> My PR is 37 while trying, but it's more like 8-10 during any regular
>>> session before a faster or slower pace is displayed for at least 1
>>> stroke. Using Watts is a good way to divert yourself from being
>>> obsessed with a particular pace, but Cal/hr would serve the same
>>> purpose for that. The PM speaks several languages, pick the one you
>>> like and go with it. [:o)
>>> If you want your pace displayed to one decimal place you can always go
>>> with ErgMonitor (tm). EM also shows Watts without having to change
>>> screen modes, plus a bunch of other stuff. (slight understatement)
>>> LOL
>>> - Paul Smith
>> Just curious (not a jab, honestly) did you ever figure out how EM's
>> instantaneous power numbers are calculated (i.e. each power data point
>> on one of the power curves)? They don't equal handle force x handle
>> velocity, so I've been curious what the numbers do equal (i.e. what do
>> they mean).
>>
>> -KC
>
> Magic. That's why the Pace works out to be so close to the PM.
>
> Sorry, I can't take you seriously after learning how you perceive your
> dogs level of intelligence.
>
> Jab away.
>
> - Paul Smith

No wonder you support people like Palin and W. If you're comfortable
selling a product you don't understand and can't explain, it makes sense
you'd be comfortable with leaders who don't understand and can't explain
.... anything. (Note I left McCain out of that comparison, whom I think
actually has a decent level of intelligence.)

My question wasn't a jab. It was serious. I'm sorry you can't seem to
let go of remarks made in jest and move on. I really honestly am
curious about what an instantaneous value of "power" is when reported by
EM. I can't make use of a tool if I don't understand what it's
measuring or reporting. I'm not saying that EM is useless - it is very
accurate on the pace and other readings. And maybe these "power" values
are real. I just don't understand what they are, and would like to.

-KC

Jake

10-08-2008, 01:29 PM

>"splits" isn't linear because it estimates the
speed you'd go in a viscous medium (water) by dealing with the
acceleration/deceleration of a fan in a viscous medium (air).

More explicitly, I read somewhere it estimates the speed you'd go in a
VIII+ in still water with 7 other identical yous pulling as hard and
with efficient technique and a cox steering.

This is why you can only pull, say, a 1:45 for a few strokes in real
life on the water in a single scull with a speedcoach, but manage it
for several thousand metres on an ergo.

kdavies@kidare.com

10-08-2008, 02:36 PM

On 8 Oct, 13:29, Jake <jake.fr...@rya.org.uk> wrote:
> This is why you can only pull, say, a 1:45 for a few strokes in real
> life on the water in a single scull with a speedcoach, but manage it
> for several thousand metres on an ergo.

*gulp*

Peter Ford

10-08-2008, 03:22 PM

On Oct 8, 1:29 pm, Jake <jake.fr...@rya.org.uk> wrote:
> >"splits" isn't linear because it estimates the
>
> speed you'd go in a viscous medium (water) by dealing with the
> acceleration/deceleration of a fan in a viscous medium (air).
>
> More explicitly, I read somewhere it estimates the speed you'd go in a
> VIII+ in still water with 7 other identical yous pulling as hard and
> with efficient technique and a cox steering.
>
> This is why you can only pull, say, a 1:45 for a few strokes in real
> life on the water in a single scull with a speedcoach, but manage it
> for several thousand metres on an ergo.

I can't find a source atm, but my memory of it is that it's
standardised based on a 4- with 90 or 95 kg rowers; so in particular
lightweights pulling 6:30s should be able to go a fair way sub 6:30 on
the water in a 4-

Peter

paul_v_smith@hotmail.com

10-08-2008, 03:48 PM

On Oct 8, 7:22 am, Peter Ford <p3t3r.f...@gmail.com> wrote:
> On Oct 8, 1:29 pm, Jake <jake.fr...@rya.org.uk> wrote:
>
> > >"splits" isn't linear because it estimates the
>
> > speed you'd go in a viscous medium (water) by dealing with the
> > acceleration/deceleration of a fan in a viscous medium (air).
>
> > More explicitly, I read somewhere it estimates the speed you'd go in a
> > VIII+ in still water with 7 other identical yous pulling as hard and
> > with efficient technique and a cox steering.
>
> > This is why you can only pull, say, a 1:45 for a few strokes in real
> > life on the water in a single scull with a speedcoach, but manage it
> > for several thousand metres on an ergo.
>
> I can't find a source atm, but my memory of it is that it's
> standardised based on a 4- with 90 or 95 kg rowers; so in particular
> lightweights pulling 6:30s should be able to go a fair way sub 6:30 on
> the water in a 4-
>
> Peter

Once again, you're very close. M4- 100kg (Rowing Biomechanics
Newsletter has the details on that.) or M4+ 85kg (allowing for minimum
cox weight) I suppose.

Your theoretical LWT's would have about a 5 second advantage over
their Erg Pace in the LM4-. IOW, they could go twice as far in the
boat at the same Pace as they could on the Erg.

Of course this assumes a connection to the water that rivals the chain/
cog interface of the Erg, which may or may not occur due to what
happens at the catch, or "blade entry" for those that don't like the
term "catch". [:o)

- Paul

paul_v_smith@hotmail.com

10-08-2008, 04:21 PM

On Oct 7, 5:28 pm, KC <kc_n...@sonic.net> wrote:
> paul_v_sm...@hotmail.com wrote:
> > On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
> >> paul_v_sm...@hotmail.com wrote:
> >>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> >>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
> >>>>> Question posted by a surf boat rower on their newsgroup for you guys
> >>>>> to help answer!
> >>>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
> >>>>> twice the weight as they use their body weight to steer the boat down
> >>>>> waves- also often the coach of the crew).
> >>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
> >>>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak'Wattage displayed?
> >>>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
> >>>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
> >>>> It's the average power output through the stroke (and recovery).
> >>>> If you're doing several pieces stepping up the work, then it's
> >>>> probably better to step up watts than split (or at least be aware that
> >>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> >>>> between the second and third pieces than first and second; and you'll
> >>>> feel it). If you care about being very accurately on a pace, watts is
> >>>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
> >>>> split, but both will just show up as '1:50' on the monitor.
> >>>> Pete
> >>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> >>> correct about the Avg power per stroke cycle. But how many
> >>> consecutive strokes will show the exact same displayed pace anyhow?
> >>> My PR is 37 while trying, but it's more like 8-10 during any regular
> >>> session before a faster or slower pace is displayed for at least 1
> >>> stroke. Using Watts is a good way to divert yourself from being
> >>> obsessed with a particular pace, but Cal/hr would serve the same
> >>> purpose for that. The PM speaks several languages, pick the one you
> >>> like and go with it. [:o)
> >>> If you want your pace displayed to one decimal place you can always go
> >>> with ErgMonitor (tm). EM also shows Watts without having to change
> >>> screen modes, plus a bunch of other stuff. (slight understatement)
> >>> LOL
> >>> - Paul Smith
> >> Just curious (not a jab, honestly) did you ever figure out how EM's
> >> instantaneous power numbers are calculated (i.e. each power data point
> >> on one of the power curves)? They don't equal handle force x handle
> >> velocity, so I've been curious what the numbers do equal (i.e. what do
> >> they mean).
>
> >> -KC
>
> > Magic. That's why the Pace works out to be so close to the PM.
>
> > Sorry, I can't take you seriously after learning how you perceive your
> > dogs level of intelligence.
>
> > Jab away.
>
> > - Paul Smith
>
> No wonder you support people like Palin and W. If you're comfortable
> selling a product you don't understand and can't explain, it makes sense
> you'd be comfortable with leaders who don't understand and can't explain
> ... anything. (Note I left McCain out of that comparison, whom I think
> actually has a decent level of intelligence.)
>
> My question wasn't a jab. It was serious. I'm sorry you can't seem to
> let go of remarks made in jest and move on. I really honestly am
> curious about what an instantaneous value of "power" is when reported by
> EM. I can't make use of a tool if I don't understand what it's
> measuring or reporting. I'm not saying that EM is useless - it is very
> accurate on the pace and other readings. And maybe these "power" values
> are real. I just don't understand what they are, and would like to.
>
> -KC

Boy I must be lucky?! To have designed something that works, even
though I don't know how or why. If we could all be so fortunate. LOL

Ah, so now it was "in jest", I suppose I can take your word for that,
otherwise it would be logical to conclude you are insane. Attempting
to explain things to insane people is not generally productive.
Anyway, yer so smart, go figure it out for yourself, Anu Dudhia's
pages on The physics of ergometers should be enough, after all that's
where many of the formulas came from. His analysis of Slides Vs
Grounded Erg is completely wrong, but the other stuff seemed to work
out.

As usual, Jab away, since you apparently have no ability to restrain
yourself. Seems you've spent too much time trying to become educated,
how is that working out for you, anything productive come out of it
yet?

- Paul Smith

PS - I was rather successful at selling computers for a number of
years and don't claim to know exactly how they work either. I also
know next to nothing regarding internal ballistics, but that doesn't
apparently effect my marksmanship. (Since Walter may be lurking about,
I recently put 3 consecutive shots in a 0.176" group at 200yd, from a
rifle that I had never known except for those 3 shots. All due credit
to the gunsmith and ammunition assembler, of course. Anyone can pull
a trigger!) LOL

10-08-2008, 05:54 PM

paul_v_smith@hotmail.com wrote:
> On Oct 7, 5:28 pm, KC <kc_n...@sonic.net> wrote:
>> paul_v_sm...@hotmail.com wrote:
>>> On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
>>>> paul_v_sm...@hotmail.com wrote:
>>>>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
>>>>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
>>>>>>> Question posted by a surf boat rower on their newsgroup for you guys
>>>>>>> to help answer!
>>>>>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
>>>>>>> twice the weight as they use their body weight to steer the boat down
>>>>>>> waves- also often the coach of the crew).
>>>>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
>>>>>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
>>>>>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
>>>>>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
>>>>>> It's the average power output through the stroke (and recovery).
>>>>>> If you're doing several pieces stepping up the work, then it's
>>>>>> probably better to step up watts than split (or at least be aware that
>>>>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
>>>>>> between the second and third pieces than first and second; and you'll
>>>>>> feel it). If you care about being very accurately on a pace, watts is
>>>>>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
>>>>>> split, but both will just show up as '1:50' on the monitor.
>>>>>> Pete
>>>>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
>>>>> correct about the Avg power per stroke cycle. But how many
>>>>> consecutive strokes will show the exact same displayed pace anyhow?
>>>>> My PR is 37 while trying, but it's more like 8-10 during any regular
>>>>> session before a faster or slower pace is displayed for at least 1
>>>>> stroke. Using Watts is a good way to divert yourself from being
>>>>> obsessed with a particular pace, but Cal/hr would serve the same
>>>>> purpose for that. The PM speaks several languages, pick the one you
>>>>> like and go with it. [:o)
>>>>> If you want your pace displayed to one decimal place you can always go
>>>>> with ErgMonitor (tm). EM also shows Watts without having to change
>>>>> screen modes, plus a bunch of other stuff. (slight understatement)
>>>>> LOL
>>>>> - Paul Smith
>>>> Just curious (not a jab, honestly) did you ever figure out how EM's
>>>> instantaneous power numbers are calculated (i.e. each power data point
>>>> on one of the power curves)? They don't equal handle force x handle
>>>> velocity, so I've been curious what the numbers do equal (i.e. what do
>>>> they mean).
>>>> -KC
>>> Magic. That's why the Pace works out to be so close to the PM.
>>> Sorry, I can't take you seriously after learning how you perceive your
>>> dogs level of intelligence.
>>> Jab away.
>>> - Paul Smith
>> No wonder you support people like Palin and W. If you're comfortable
>> selling a product you don't understand and can't explain, it makes sense
>> you'd be comfortable with leaders who don't understand and can't explain
>> ... anything. (Note I left McCain out of that comparison, whom I think
>> actually has a decent level of intelligence.)
>>
>> My question wasn't a jab. It was serious. I'm sorry you can't seem to
>> let go of remarks made in jest and move on. I really honestly am
>> curious about what an instantaneous value of "power" is when reported by
>> EM. I can't make use of a tool if I don't understand what it's
>> measuring or reporting. I'm not saying that EM is useless - it is very
>> accurate on the pace and other readings. And maybe these "power" values
>> are real. I just don't understand what they are, and would like to.
>>
>> -KC
>
> Boy I must be lucky?! To have designed something that works, even
> though I don't know how or why. If we could all be so fortunate. LOL
>
> Ah, so now it was "in jest", I suppose I can take your word for that,
> otherwise it would be logical to conclude you are insane. Attempting

The fact that you often take such statements at face value makes me
question YOUR sanity. Or at least it makes me assume that you might
have some mental disorder like Ashperger Syndrome (characterized by
difficulties with social interaction). Although you apparently lack the
physical clumsiness that usually goes with AS, so If not full-blown,
maybe at least on the marginal Autism spectrum.

> to explain things to insane people is not generally productive.
> Anyway, yer so smart, go figure it out for yourself, Anu Dudhia's

You keep telling me how smart you think I am, yet you never accept
anything I have to say as true, or correct. This is another indication
of borderline mental disorder. Or are you just joking? If you really
do NOT think I'm smart, then you're just cruel to send off someone to
study a physics page whom you don't think has the capacity to understand
it. Either way, your behavior is not indicative of mental soundness.

> pages on The physics of ergometers should be enough, after all that's
> where many of the formulas came from. His analysis of Slides Vs
> Grounded Erg is completely wrong, but the other stuff seemed to work
> out.

So the man with a PhD in physics is spot on when you need/want him to
be, but when his analysis differs from what you, in all your vast
(mis)understanding of physics, think you know, he's "completely wrong".

Precious.

I have looked at the equations for the physics of ergometers, back when
I was trying to use your software for a project. His equations all make
sense. The instantaneous power data coming out of EM doesn't. I'm
guessing that what you or your programmer decided to call "power"
doesn't really have units of power, or if it does the units don't match
(e.g. using instantaneous force with average velocity - units are Watts,
but they are incorrectly calculated and meaningless). Which is fine,
but it would be nice to know what it is. It might be useful, but until
it's defined, those units are useless (again, I'm talking about the
instantaneous units called "power" not the average power per stroke
units which do make sense).

This situation is as if someone gave me a laser range finder with a
display for results, but the results don't have units, and don't seem to
match up with any distance units I'm familiar with. Maybe the display
is really showing the time for the light beam's round trip, which can be
converted to distance. But until the display units are defined, the
device is useless.

> As usual, Jab away, since you apparently have no ability to restrain
> yourself. Seems you've spent too much time trying to become educated,

No jabs here. Just observations.

> how is that working out for you, anything productive come out of it
> yet?
>
> - Paul Smith
>
> PS - I was rather successful at selling computers for a number of
> years and don't claim to know exactly how they work either. I also
> know next to nothing regarding internal ballistics, but that doesn't
> apparently effect my marksmanship. (Since Walter may be lurking about,

You forgot the most apropos example: The fact that you have a few
massive misconceptions about the physics of rowing doesn't apparently
affect (with an a) your skill as a rower (I'm going by your own horn
tooting - I've never seen you row obviously).

Salesmen don't always have to understand every detail of the inner
workings of their products. They often don't. But they can and should
be able to explain all the features, and what they are meant and/or used
for. Or, when they can't explain something a good salesman admits it
(btw, that's done by saying "I don't know") and then goes back to the
designers or engineers who do understand it, gets the information and
brings it back to the customer. Novel concept I know. But it works out
really well for others. You might consider it.

> I recently put 3 consecutive shots in a 0.176" group at 200yd, from a
> rifle that I had never known except for those 3 shots. All due credit
> to the gunsmith and ammunition assembler, of course. Anyone can pull
> a trigger!) LOL

I disagree. Anyone can pull a trigger and achieve what you did IF the
firearm is rigidly mounted to a relatively immobile platform. What you
did requires a lot of fine motor skill and neuromuscular control.

Curious - how do you measure the grouping? I have no idea, but I would
guess you'd report the maximum distance between any two target holes.
Isn't 0.176" less than the caliber of the bullet? If so, how do you
measure that distance? Or were you shooting BBs? :^)

-KC

10-08-2008, 05:57 PM

Peter Ford wrote:
> On Oct 8, 1:29 pm, Jake <jake.fr...@rya.org.uk> wrote:
>>> "splits" isn't linear because it estimates the
>> speed you'd go in a viscous medium (water) by dealing with the
>> acceleration/deceleration of a fan in a viscous medium (air).
>>
>> More explicitly, I read somewhere it estimates the speed you'd go in a
>> VIII+ in still water with 7 other identical yous pulling as hard and
>> with efficient technique and a cox steering.
>>
>> This is why you can only pull, say, a 1:45 for a few strokes in real
>> life on the water in a single scull with a speedcoach, but manage it
>> for several thousand metres on an ergo.
>
> I can't find a source atm, but my memory of it is that it's
> standardised based on a 4- with 90 or 95 kg rowers; so in particular
> lightweights pulling 6:30s should be able to go a fair way sub 6:30 on
> the water in a 4-
>
> Peter

I recall being told the same or a similar thing at one time. I don't
know if it's true, but it seems to work out fairly well. In college our
scores seemed to match our 4+ speed (most of us were ~90kg excepting of
course the cox!)

-KC

paul_v_smith@hotmail.com

10-08-2008, 08:17 PM

On Oct 8, 9:54 am, kc <kc_n...@sonic.net> wrote:
>
> Curious - how do you measure the grouping? I have no idea, but I would
> guess you'd report the maximum distance between any two target holes.
> Isn't 0.176" less than the caliber of the bullet? If so, how do you
> measure that distance? Or were you shooting BBs? :^)
>
> -KC

It's called a CTC (Center to Center) measurement, calculated by
measuring the extreme boundary edges of the impacts and subtracting
the caliber. i.e. A single hole would be a 0.000" group (well not
really a group, as it was only one shot, but surely you get the
idea.).

Good to see that you know your BB's, almost. (0.177" BTW)

If you are asking about the "Power" unit, under the Spike Data in the
Text Log view, it's the Watts being absorbed by the flywheel at that
given moment. (Of course it says that when the unit is selected,
can't you read?)

As for the rest, just more of the same idiocy I see from you when you
get bent. Bub-bye now....

- Paul Smith

Ted van de Weteringe

10-08-2008, 08:30 PM

paul_v_smith@hotmail.com wrote:
> If you are asking about the "Power" unit, under the Spike Data in the
> Text Log view, it's the Watts being absorbed by the flywheel at that
> given moment.

"Watts absorption" (energy dissipation?) is not a meaningful concept for
one given moment. Between two points in time, yes.

10-08-2008, 09:18 PM

paul_v_smith@hotmail.com wrote:
> On Oct 8, 9:54 am, kc <kc_n...@sonic.net> wrote:
>> Curious - how do you measure the grouping? I have no idea, but I would
>> guess you'd report the maximum distance between any two target holes.
>> Isn't 0.176" less than the caliber of the bullet? If so, how do you
>> measure that distance? Or were you shooting BBs? :^)
>>
>> -KC
>
> It's called a CTC (Center to Center) measurement, calculated by
> measuring the extreme boundary edges of the impacts and subtracting
> the caliber. i.e. A single hole would be a 0.000" group (well not
> really a group, as it was only one shot, but surely you get the
> idea.).

I guess we can't all be Robin Hood. :^)
(2 shots one hole).

> Good to see that you know your BB's, almost. (0.177" BTW)

Lucky guess. I was just trying to think of the smallest caliber
"bullet" I could think of. Is there something smaller than a BB that
some guns fire/shoot? "Pellets" are the same caliber as BBs right?

> If you are asking about the "Power" unit, under the Spike Data in the
> Text Log view, it's the Watts being absorbed by the flywheel at that
> given moment.

No it isn't. Watts = force on the handle * velocity of the handle, at
any given instant. Take the handle velocity at the same moment, and the
handle force at that moment, and you get the Watts absorbed by the
flywheel at that moment. This is not the number EM reports. Check it
yourself, it's easy enough since EM also reports instantaneous handle
velocity and handle force.

> (Of course it says that when the unit is selected,
> can't you read?)

Yes, which is why I brought this up. Your software says one thing, but
when I do some simple math to check, it doesn't match. So maybe you
need to just change the description of those numbers, as unless I'm
mistaken somewhere, they are not Watts absorbed by the flywheel at that
moment. Maybe have EM say something like "We have no idea what these
numbers are, but maybe you the user might find them interesting."
Saying that they are instantaneous Watts is AFAICT, wrong and misleading.

Alternatively, if you want to make EM report the correct values that
you're trying to report, all you have to do is remove (don't report in
the spike data) the current erroneous "Power" numbers, and just insert a
few lines of code that multiplies handle force * handle velocity at a
given instant in time, and you're golden. I did the same thing in my
own (MATLAB) code when I was using EM's spike data output.

This BTW, is what's called a user bug report. You're the only software
vendor/manufacturer I've EVER come across who's been so opposed to &
closed minded about such a thing. You have, AFAICT, a mistake in your
product, the fix is easy, and yet you have thus far refused to
acknowledge it or even explain it.

> As for the rest, just more of the same idiocy I see from you when you
> get bent. Bub-bye now....

Not 'bent' at all. Perfectly cool, calm, collected, and content.

-KC

paul_v_smith@hotmail.com

10-08-2008, 09:18 PM

On Oct 8, 12:30 pm, Ted van de Weteringe
<myfulln...@xs4all.nl.invalid> wrote:
> paul_v_sm...@hotmail.com wrote:
> > If you are asking about the "Power" unit, under the Spike Data in the
> > Text Log view, it's the Watts being absorbed by the flywheel at that
> > given moment.
>
> "Watts absorption" (energy dissipation?) is not a meaningful concept for
> one given moment. Between two points in time, yes.

Thanks for clarifying that. In the USA a "moment" is not an
"instant", it implies an interval of time, in this case the time
between two pulses from the flywheel sensor.

- Paul Smith

10-08-2008, 09:22 PM

Ted van de Weteringe wrote:
> paul_v_smith@hotmail.com wrote:
>> If you are asking about the "Power" unit, under the Spike Data in the
>> Text Log view, it's the Watts being absorbed by the flywheel at that
>> given moment.
>
> "Watts absorption" (energy dissipation?) is not a meaningful concept for
> one given moment. Between two points in time, yes.

Sure it is. It's the time rate of change of the Energy. Surely you've
studied derivatives in 1st year Calculus? If not I apologize. Anyway,
it's just the slope of the Energy-time curve at any instant in time.
It's very meaningful, and can easily be calculated by P=F*V as explained
in my last post to Paul.

-KC

Teaplant

10-08-2008, 09:40 PM

On 8 Oct, 20:30, Ted van de Weteringe <myfulln...@xs4all.nl.invalid>
wrote:
> paul_v_sm...@hotmail.com wrote:
> > If you are asking about the "Power" unit, under the Spike Data in the
> > Text Log view, it's the Watts being absorbed by the flywheel at that
> > given moment.
>
> "Watts absorption" (energy dissipation?) is not a meaningful concept for
> one given moment. Between two points in time, yes.

Its a crazy phrase of course...but watt (being a unit of power = RATE
of transfer of energy) is correct as an instantaneous concept.

Energy is not - but that was your mistake, not his!
(Of course the monitor is likely to be measuring instantaneous values
of the angular velocity of the wheel and from that updating its value
for the rotational KE over successive small-ish time intervals).

Power = force*velocity this is true for the rate of work done by the
rower on the ergo handle. This is not the same as power = rate of
increase of rotational KE of the wheel, although it ought to be
similar (the latter should be more than the former). For instance
some of the work being done becomes KE of the chain and handle, some
is stored in strain energy of the elastic return cords etc.

While we're at it... watts takes a lower case "w". It's not somebody's
name, it is the unit of power.
See, I can be petty too. I'm not as good as Paul or KC though. Over
to you two...

teaplant.

wmartind@gmail.com

10-08-2008, 10:34 PM

On Oct 9, 4:21 am, paul_v_sm...@hotmail.com wrote:
> On Oct 7, 5:28 pm, KC <kc_n...@sonic.net> wrote:
>
>
>
> > paul_v_sm...@hotmail.com wrote:
> > > On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
> > >> paul_v_sm...@hotmail.com wrote:
> > >>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> > >>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
> > >>>>> Question posted by a surf boat rower on their newsgroup for you guys
> > >>>>> to help answer!
> > >>>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
> > >>>>> twice the weight as they use their body weight to steer the boat down
> > >>>>> waves- also often the coach of the crew).
> > >>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
> > >>>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
> > >>>>>> To the smart ar*es: I know to get the Wattage higher I just haveto pull harder.
> > >>>>>> Just trying to get my head around it because I prefer to have itset on time/500m and my >sweep prefers me to have it on Watts for some drills.
> > >>>> It's the average power output through the stroke (and recovery).
> > >>>> If you're doing several pieces stepping up the work, then it's
> > >>>> probably better to step up watts than split (or at least be aware that
> > >>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> > >>>> between the second and third pieces than first and second; and you'll
> > >>>> feel it). If you care about being very accurately on a pace, wattsis
> > >>>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
> > >>>> split, but both will just show up as '1:50' on the monitor.
> > >>>> Pete
> > >>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> > >>> correct about the Avg power per stroke cycle. But how many
> > >>> consecutive strokes will show the exact same displayed pace anyhow?
> > >>> My PR is 37 while trying, but it's more like 8-10 during any regular
> > >>> session before a faster or slower pace is displayed for at least 1
> > >>> stroke. Using Watts is a good way to divert yourself from being
> > >>> obsessed with a particular pace, but Cal/hr would serve the same
> > >>> purpose for that. The PM speaks several languages, pick the one you
> > >>> like and go with it. [:o)
> > >>> If you want your pace displayed to one decimal place you can alwaysgo
> > >>> with ErgMonitor (tm). EM also shows Watts without having to change
> > >>> screen modes, plus a bunch of other stuff. (slight understatement)
> > >>> LOL
> > >>> - Paul Smith
> > >> Just curious (not a jab, honestly) did you ever figure out how EM's
> > >> instantaneous power numbers are calculated (i.e. each power data point
> > >> on one of the power curves)? They don't equal handle force x handle
> > >> velocity, so I've been curious what the numbers do equal (i.e. what do
> > >> they mean).
>
> > >> -KC
>
> > > Magic. That's why the Pace works out to be so close to the PM.
>
> > > Sorry, I can't take you seriously after learning how you perceive your
> > > dogs level of intelligence.
>
> > > Jab away.
>
> > > - Paul Smith
>
> > No wonder you support people like Palin and W. If you're comfortable
> > selling a product you don't understand and can't explain, it makes sense
> > you'd be comfortable with leaders who don't understand and can't explain
> > ... anything. (Note I left McCain out of that comparison, whom I think
> > actually has a decent level of intelligence.)
>
> > My question wasn't a jab. It was serious. I'm sorry you can't seem to
> > let go of remarks made in jest and move on. I really honestly am
> > curious about what an instantaneous value of "power" is when reported by
> > EM. I can't make use of a tool if I don't understand what it's
> > measuring or reporting. I'm not saying that EM is useless - it is very
> > accurate on the pace and other readings. And maybe these "power" values
> > are real. I just don't understand what they are, and would like to.
>
> > -KC
>
> Boy I must be lucky?! To have designed something that works, even
> though I don't know how or why. If we could all be so fortunate. LOL
>
> Ah, so now it was "in jest", I suppose I can take your word for that,
> otherwise it would be logical to conclude you are insane. Attempting
> to explain things to insane people is not generally productive.
> Anyway, yer so smart, go figure it out for yourself, Anu Dudhia's
> pages on The physics of ergometers should be enough, after all that's
> where many of the formulas came from. His analysis of Slides Vs
> Grounded Erg is completely wrong, but the other stuff seemed to work
> out.
>
> As usual, Jab away, since you apparently have no ability to restrain
> yourself. Seems you've spent too much time trying to become educated,
> how is that working out for you, anything productive come out of it
> yet?
>
> - Paul Smith
>
> PS - I was rather successful at selling computers for a number of
> years and don't claim to know exactly how they work either. I also
> know next to nothing regarding internal ballistics, but that doesn't
> apparently effect my marksmanship. (Since Walter may be lurking about,
> I recently put 3 consecutive shots in a 0.176" group at 200yd, from a
> rifle that I had never known except for those 3 shots. All due credit
> to the gunsmith and ammunition assembler, of course. Anyone can pull
> a trigger!) LOL

That's good shooting. I'm happy with 3/4 minute vertical dispersion
using nato 5.56 at 600 m prone off elbows with sling support and a 3
pound trigger. Long time since I did that.
Rifle's still good for it, I'm badly out of practice.
W

Ted van de Weteringe

10-08-2008, 10:46 PM

Teaplant wrote:
> On 8 Oct, 20:30, Ted van de Weteringe wrote:
>> "Watts absorption" (energy dissipation?) is not a meaningful concept for
>> one given moment. Between two points in time, yes.
>
> Its a crazy phrase of course...but watt (being a unit of power = RATE
> of transfer of energy) is correct as an instantaneous concept.
>
> Energy is not - but that was your mistake, not his!

Sorry, my interpretation error.

Carl Douglas

10-09-2008, 12:34 AM

Teaplant wrote:
> On 8 Oct, 20:30, Ted van de Weteringe <myfulln...@xs4all.nl.invalid>
> wrote:
>> paul_v_sm...@hotmail.com wrote:
>>> If you are asking about the "Power" unit, under the Spike Data in the
>>> Text Log view, it's the Watts being absorbed by the flywheel at that
>>> given moment.
>> "Watts absorption" (energy dissipation?) is not a meaningful concept for
>> one given moment. Between two points in time, yes.
>
> Its a crazy phrase of course...but watt (being a unit of power = RATE
> of transfer of energy) is correct as an instantaneous concept.
>
> Energy is not - but that was your mistake, not his!
> (Of course the monitor is likely to be measuring instantaneous values
> of the angular velocity of the wheel and from that updating its value
> for the rotational KE over successive small-ish time intervals).
>
> Power = force*velocity this is true for the rate of work done by the
> rower on the ergo handle. This is not the same as power = rate of
> increase of rotational KE of the wheel, although it ought to be
> similar (the latter should be more than the former). For instance
> some of the work being done becomes KE of the chain and handle, some
> is stored in strain energy of the elastic return cords etc.

Well, let's be picky, shall we?

Instantaneous stroke power = rate of inc. of rotational KE, _plus_ rate
of power dissipation by the fan, plus rate of input of energy into
stretching bungee, plus rate of inc. of body KE as it moves along the slide.

After the finish there's a further dissipation of energy (work to do)
= rate of inc. in bodily KE in moving from stasis towards the catch.

In the short distance before the catch there's a further energy
dissipation term (more work to do)
= rate of decr. in bodily KE to bring the body to a halt before moving
back up the slide.

Neither of those last 2 terms is computed, nor are they avoidable, nor
are they insignificant, nor do they have equivalents in the actual boat.
They constitute parasitic work done by the rower during the erg stroke
that is simply ignored by the erg computation. Try "rowing" up & down
the erg slide without pulling the handle & you'll see what I mean.

Strange that rowing is content to ignore such a term when supposedly
making precise measurements of a rower's work rate.

>
> While we're at it... watts takes a lower case "w". It's not somebody's
> name, it is the unit of power.
> See, I can be petty too. I'm not as good as Paul or KC though. Over
> to you two...
>
> teaplant.

Practice makes perfect.

;)
Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)

paul_v_smith@hotmail.com

10-09-2008, 01:25 AM

On Oct 8, 2:34 pm, wmart...@gmail.com wrote:
> On Oct 9, 4:21 am, paul_v_sm...@hotmail.com wrote:
>
>
>
> > On Oct 7, 5:28 pm, KC <kc_n...@sonic.net> wrote:
>
> > > paul_v_sm...@hotmail.com wrote:
> > > > On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
> > > >> paul_v_sm...@hotmail.com wrote:
> > > >>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> > > >>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
> > > >>>>> Question posted by a surf boat rower on their newsgroup for youguys
> > > >>>>> to help answer!
> > > >>>>> (A sweep is the surf boats semi equivalent of a coxswain but atleast
> > > >>>>> twice the weight as they use their body weight to steer the boat down
> > > >>>>> waves- also often the coach of the crew).
> > > >>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
> > > >>>>>> I know Watts are joules per second, so is the watt's score thetotal joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
> > > >>>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
> > > >>>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for some drills.
> > > >>>> It's the average power output through the stroke (and recovery).
> > > >>>> If you're doing several pieces stepping up the work, then it's
> > > >>>> probably better to step up watts than split (or at least be aware that
> > > >>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> > > >>>> between the second and third pieces than first and second; and you'll
> > > >>>> feel it). If you care about being very accurately on a pace, watts is
> > > >>>> better: there's a fair bit of difference between 1:50.0 and 1:50..9
> > > >>>> split, but both will just show up as '1:50' on the monitor.
> > > >>>> Pete
> > > >>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> > > >>> correct about the Avg power per stroke cycle. But how many
> > > >>> consecutive strokes will show the exact same displayed pace anyhow?
> > > >>> My PR is 37 while trying, but it's more like 8-10 during any regular
> > > >>> session before a faster or slower pace is displayed for at least 1
> > > >>> stroke. Using Watts is a good way to divert yourself from being
> > > >>> obsessed with a particular pace, but Cal/hr would serve the same
> > > >>> purpose for that. The PM speaks several languages, pick the one you
> > > >>> like and go with it. [:o)
> > > >>> If you want your pace displayed to one decimal place you can always go
> > > >>> with ErgMonitor (tm). EM also shows Watts without having to change
> > > >>> screen modes, plus a bunch of other stuff. (slight understatement)
> > > >>> LOL
> > > >>> - Paul Smith
> > > >> Just curious (not a jab, honestly) did you ever figure out how EM's
> > > >> instantaneous power numbers are calculated (i.e. each power data point
> > > >> on one of the power curves)? They don't equal handle force x handle
> > > >> velocity, so I've been curious what the numbers do equal (i.e. what do
> > > >> they mean).
>
> > > >> -KC
>
> > > > Magic. That's why the Pace works out to be so close to the PM.
>
> > > > Sorry, I can't take you seriously after learning how you perceive your
> > > > dogs level of intelligence.
>
> > > > Jab away.
>
> > > > - Paul Smith
>
> > > No wonder you support people like Palin and W. If you're comfortable
> > > selling a product you don't understand and can't explain, it makes sense
> > > you'd be comfortable with leaders who don't understand and can't explain
> > > ... anything. (Note I left McCain out of that comparison, whom I think
> > > actually has a decent level of intelligence.)
>
> > > My question wasn't a jab. It was serious. I'm sorry you can't seem to
> > > let go of remarks made in jest and move on. I really honestly am
> > > curious about what an instantaneous value of "power" is when reportedby
> > > EM. I can't make use of a tool if I don't understand what it's
> > > measuring or reporting. I'm not saying that EM is useless - it is very
> > > accurate on the pace and other readings. And maybe these "power" values
> > > are real. I just don't understand what they are, and would like to..
>
> > > -KC
>
> > Boy I must be lucky?! To have designed something that works, even
> > though I don't know how or why. If we could all be so fortunate. LOL
>
> > Ah, so now it was "in jest", I suppose I can take your word for that,
> > otherwise it would be logical to conclude you are insane. Attempting
> > to explain things to insane people is not generally productive.
> > Anyway, yer so smart, go figure it out for yourself, Anu Dudhia's
> > pages on The physics of ergometers should be enough, after all that's
> > where many of the formulas came from. His analysis of Slides Vs
> > Grounded Erg is completely wrong, but the other stuff seemed to work
> > out.
>
> > As usual, Jab away, since you apparently have no ability to restrain
> > yourself. Seems you've spent too much time trying to become educated,
> > how is that working out for you, anything productive come out of it
> > yet?
>
> > - Paul Smith
>
> > PS - I was rather successful at selling computers for a number of
> > years and don't claim to know exactly how they work either. I also
> > know next to nothing regarding internal ballistics, but that doesn't
> > apparently effect my marksmanship. (Since Walter may be lurking about,
> > I recently put 3 consecutive shots in a 0.176" group at 200yd, from a
> > rifle that I had never known except for those 3 shots. All due credit
> > to the gunsmith and ammunition assembler, of course. Anyone can pull
> > a trigger!) LOL
>
> That's good shooting. I'm happy with 3/4 minute vertical dispersion
> using nato 5.56 at 600 m prone off elbows with sling support and a 3
> pound trigger. Long time since I did that.
> Rifle's still good for it, I'm badly out of practice.
> W

RSR - Rec.Sport.Rifle entry:

That would make me happy too. This was from a bench, but only
mechanical support on the fore end, and a 1lb trigger. The owner
asked "You've done this before?" I replied, "No, that's pretty
unusual." He did let me cut out the target.
http://www.ps-sport.net/pictures/6.5mmGroup_200yd.jpg
I'll be heading to the range tomorrow for some barrel lapping to see
if it helps tighten up my long range gun a bit, otherwise it will be
off to get a new barrel when I can afford it. I fear being spoiled
after not having been to the range for a few years and getting that
result. But at least I got the name of his gunsmith. I'm also
unlikely to go to the extremes of case preparation that he did, which
could well be the difference.
I do have a rifle that shoots like the above, but it's a 10lb hunting
rig and the pet load is at the hot end of the scale; so I keep it for
special occasions and keep trying to get the other one up to snuff.

Are you shooting the 5.56 out of the AR-15/M16 platform, or something
else? I've been impressed by the precision capability of a few AR's,
though it's a tiny pellet at 600m+. I don't have anything with enough
twist for the 75gr bullets so am stuck in the 50-62 range with the
52's working out pretty well.

- Paul Smith

wmartind@gmail.com

10-09-2008, 02:05 AM

On Oct 9, 1:25 pm, paul_v_sm...@hotmail.com wrote:
> On Oct 8, 2:34 pm, wmart...@gmail.com wrote:
>
>
>
> > On Oct 9, 4:21 am, paul_v_sm...@hotmail.com wrote:
>
> > > On Oct 7, 5:28 pm, KC <kc_n...@sonic.net> wrote:
>
> > > > paul_v_sm...@hotmail.com wrote:
> > > > > On Oct 7, 8:56 am, kc <kc_n...@sonic.net> wrote:
> > > > >> paul_v_sm...@hotmail.com wrote:
> > > > >>> On Oct 7, 7:41 am, Pete <petersr1...@hotmail.com> wrote:
> > > > >>>> On 7 Oct, 01:33, nickystaite <nickysta...@hotmail.com> wrote:
> > > > >>>>> Question posted by a surf boat rower on their newsgroup for you guys
> > > > >>>>> to help answer!
> > > > >>>>> (A sweep is the surf boats semi equivalent of a coxswain but at least
> > > > >>>>> twice the weight as they use their body weight to steer the boat down
> > > > >>>>> waves- also often the coach of the crew).
> > > > >>>>>> It may be a silly question but how is the Watt's score on a concept ergo derived?
> > > > >>>>>> I know Watts are joules per second, so is the watt's score the total joules per time (length) of >the stroke (average Watts) or is the 'peak' Wattage displayed?
> > > > >>>>>> To the smart ar*es: I know to get the Wattage higher I just have to pull harder.
> > > > >>>>>> Just trying to get my head around it because I prefer to have it set on time/500m and my >sweep prefers me to have it on Watts for somedrills.
> > > > >>>> It's the average power output through the stroke (and recovery).
> > > > >>>> If you're doing several pieces stepping up the work, then it's
> > > > >>>> probably better to step up watts than split (or at least be aware that
> > > > >>>> if you do 1:50-1:45-1:40 then there is a much bigger power difference
> > > > >>>> between the second and third pieces than first and second; andyou'll
> > > > >>>> feel it). If you care about being very accurately on a pace, watts is
> > > > >>>> better: there's a fair bit of difference between 1:50.0 and 1:50.9
> > > > >>>> split, but both will just show up as '1:50' on the monitor.
> > > > >>>> Pete
> > > > >>> Actually a displayed 1:50 could be from 1:49.5 to 1:50.4. But you are
> > > > >>> correct about the Avg power per stroke cycle. But how many
> > > > >>> consecutive strokes will show the exact same displayed pace anyhow?
> > > > >>> My PR is 37 while trying, but it's more like 8-10 during any regular
> > > > >>> session before a faster or slower pace is displayed for at least 1
> > > > >>> stroke. Using Watts is a good way to divert yourself from being
> > > > >>> obsessed with a particular pace, but Cal/hr would serve the same
> > > > >>> purpose for that. The PM speaks several languages, pick the one you
> > > > >>> like and go with it. [:o)
> > > > >>> If you want your pace displayed to one decimal place you can always go
> > > > >>> with ErgMonitor (tm). EM also shows Watts without having to change
> > > > >>> screen modes, plus a bunch of other stuff. (slight understatement)
> > > > >>> LOL
> > > > >>> - Paul Smith
> > > > >> Just curious (not a jab, honestly) did you ever figure out how EM's
> > > > >> instantaneous power numbers are calculated (i.e. each power datapoint
> > > > >> on one of the power curves)? They don't equal handle force x handle
> > > > >> velocity, so I've been curious what the numbers do equal (i.e. what do
> > > > >> they mean).
>
> > > > >> -KC
>
> > > > > Magic. That's why the Pace works out to be so close to the PM.
>
> > > > > Sorry, I can't take you seriously after learning how you perceiveyour
> > > > > dogs level of intelligence.
>
> > > > > Jab away.
>
> > > > > - Paul Smith
>
> > > > No wonder you support people like Palin and W. If you're comfortable
> > > > selling a product you don't understand and can't explain, it makes sense
> > > > you'd be comfortable with leaders who don't understand and can't explain
> > > > ... anything. (Note I left McCain out of that comparison, whom Ithink
> > > > actually has a decent level of intelligence.)
>
> > > > My question wasn't a jab. It was serious. I'm sorry you can'tseem to
> > > > let go of remarks made in jest and move on. I really honestly am
> > > > curious about what an instantaneous value of "power" is when reported by
> > > > EM. I can't make use of a tool if I don't understand what it's
> > > > measuring or reporting. I'm not saying that EM is useless - it is very
> > > > accurate on the pace and other readings. And maybe these "power"values
> > > > are real. I just don't understand what they are, and would like to.
>
> > > > -KC
>
> > > Boy I must be lucky?! To have designed something that works, even
> > > though I don't know how or why. If we could all be so fortunate. LOL
>
> > > Ah, so now it was "in jest", I suppose I can take your word for that,
> > > otherwise it would be logical to conclude you are insane. Attempting
> > > to explain things to insane people is not generally productive.
> > > Anyway, yer so smart, go figure it out for yourself, Anu Dudhia's
> > > pages on The physics of ergometers should be enough, after all that's
> > > where many of the formulas came from. His analysis of Slides Vs
> > > Grounded Erg is completely wrong, but the other stuff seemed to work
> > > out.
>
> > > As usual, Jab away, since you apparently have no ability to restrain
> > > yourself. Seems you've spent too much time trying to become educated,
> > > how is that working out for you, anything productive come out of it
> > > yet?
>
> > > - Paul Smith
>
> > > PS - I was rather successful at selling computers for a number of
> > > years and don't claim to know exactly how they work either. I also
> > > know next to nothing regarding internal ballistics, but that doesn't
> > > apparently effect my marksmanship. (Since Walter may be lurking about,
> > > I recently put 3 consecutive shots in a 0.176" group at 200yd, from a
> > > rifle that I had never known except for those 3 shots. All due credit
> > > to the gunsmith and ammunition assembler, of course. Anyone can pull
> > > a trigger!) LOL
>
> > That's good shooting. I'm happy with 3/4 minute vertical dispersion
> > using nato 5.56 at 600 m prone off elbows with sling support and a 3
> > pound trigger. Long time since I did that.
> > Rifle's still good for it, I'm badly out of practice.
> > W
>
> RSR - Rec.Sport.Rifle entry:
>
> That would make me happy too. This was from a bench, but only
> mechanical support on the fore end, and a 1lb trigger. The owner
> asked "You've done this before?" I replied, "No, that's pretty
> unusual." He did let me cut out the target.http://www.ps-sport.net/pictures/6.5mmGroup_200yd.jpg
> I'll be heading to the range tomorrow for some barrel lapping to see
> if it helps tighten up my long range gun a bit, otherwise it will be
> off to get a new barrel when I can afford it. I fear being spoiled
> after not having been to the range for a few years and getting that
> result. But at least I got the name of his gunsmith. I'm also
> unlikely to go to the extremes of case preparation that he did, which
> could well be the difference.
> I do have a rifle that shoots like the above, but it's a 10lb hunting
> rig and the pet load is at the hot end of the scale; so I keep it for
> special occasions and keep trying to get the other one up to snuff.
>
> Are you shooting the 5.56 out of the AR-15/M16 platform, or something
> else? I've been impressed by the precision capability of a few AR's,
> though it's a tiny pellet at 600m+. I don't have anything with enough
> twist for the 75gr bullets so am stuck in the 50-62 range with the
> 52's working out pretty well.
>
> - Paul Smith

Sportco single shot bolt action. Epoxy-Steel bedded action, Gaillard,
button-rifled, lapped barrel. built 1995, hardly shot 1000 rds.

10-09-2008, 03:53 AM

wmartind@gmail.com

10-09-2008, 04:41 AM

On Oct 9, 3:53 pm, kc <kc_n...@sonic.net> wrote:

>
> Well, it is somebody's name, James Watt, who helped develop the steam
> engine. However, you're correct that when used as a unit of power, it
> should be written 'watt'. However, to add to the confusion, the
> abbreviation of watt is large/capital 'W'.
>
> -KC
>
Woo hoo!! I wondered if someone would answer that one...
SI units, if I remember correctly, are usually abbreviated with the
capital so
20 litres would be 20 L
20 millilitres would be 20 mL
20 watts - 20 W
20 joules would be 20 J
(and the space between the number and the label is important IIRC -
must look up my little pre-internet SI handbook)
and so on... things you remember from writing a thesis
Cheers,
W

Christopher Kerr

10-09-2008, 08:21 AM

KC wrote:

> paul_v_smith@hotmail.com wrote:
>
>> If you are asking about the "Power" unit, under the Spike Data in the
>> Text Log view, it's the Watts being absorbed by the flywheel at that
>> given moment.
>
> No it isn't. Watts = force on the handle * velocity of the handle, at
> any given instant. Take the handle velocity at the same moment, and the
> handle force at that moment, and you get the Watts absorbed by the
> flywheel at that moment. This is not the number EM reports. Check it
> yourself, it's easy enough since EM also reports instantaneous handle
> velocity and handle force.
>

If I have understood Paul correctly, handle force doesn't come into it,
because EM's not measuring the power being put in by the rower but the
power being dissipated by the flywheel. It's effectively displaying the
rotational speed of the flywheel on a non-linear scale. Trying to show the
instantaneous power input would probably give fairly inaccurate results,
because you're multiplying a second derivative by a first derivative - any
limitations in the resolution of the primary sensor would be magnified
massively.

Rob Collings

10-09-2008, 08:41 AM

On 9 Oct, 04:41, wmart...@gmail.com wrote:

> Woo hoo!! I wondered if someone would answer that one...
> SI units, if I remember correctly, are usually abbreviated with the
> capital so

Only where dervied from a name, otherwise they are lowercase. ie watts-
> W but seconds -> s. The litre is an exception (and isn't SI) because
NIST decided that they know best and changed it to a capital so there
are 2 different conventions.

Rob.

Teaplant

10-09-2008, 12:13 PM

On 9 Oct, 00:34, Carl Douglas <c...@carldouglas.co.uk> wrote:

>
> Well, let's be picky, shall we?
>
> Instantaneous stroke power = rate of inc. of rotational KE, _plus_ rate
> of power dissipation by the fan, plus rate of input of energy into
> stretching bungee, plus rate of inc. of body KE as it moves along the slide.
>
> After the finish there's a further dissipation of energy (work to do)
> = rate of inc. in bodily KE in moving from stasis towards the catch..
>
> In the short distance before the catch there's a further energy
> dissipation term (more work to do)
> = rate of decr. in bodily KE to bring the body to a halt before moving
> back up the slide.
>

Hey Carl, I felt I was informing the 'debate' between KC and PS about
the difference between KC's power (rate at which rower does work on
the handle = F*v) compared with the way the erg (and perhaps PS's
software) calculates power (rate at which KE is added to the wheel).
As I read it, KC is using the difference in these two quantities to
criticise PS regarding his software and PS is criticising KC for
historical reasons. My point is there is a good reason for the
difference, and continuing to argue about puts at least one of them in
the wrong...

All the other stuff about the difference between ergo performance and
on-water performance is, as ever, true enough but not exactly on-the-
point. All the erg 'cares about' is how much work you do on the
handle, and all it displays is the fraction of that work which is
transferred (temporarily) in the spinning flywheel.

As I see it, the main cause of much of the wrangling over the buoyancy-
or-otherwise of ergometers is the fact that they offer a 500m split
display (plus all the derivatives of it eg distance travelled).
Without this feature, we would probably all be happier about their
role in rowing training - ie as a self-loading simultaneous leg-press
and bench-pull machine with a clock on it. If one only ever set it to
read in watts, I suspect we would use it more sensibly!

Teaplant.

Ted van de Weteringe

10-09-2008, 12:56 PM

Rob Collings wrote:
> The litre is an exception (and isn't SI) because
> NIST decided that they know best and changed it to a capital so there
> are 2 different conventions.

NIST? It goes even higher than that ;) http://www.bipm.org/fr/CGPM/db/16/6/

Carl Douglas

10-09-2008, 02:21 PM

Teaplant wrote:
> On 9 Oct, 00:34, Carl Douglas <c...@carldouglas.co.uk> wrote:
>
>> Well, let's be picky, shall we?
>>
>> Instantaneous stroke power = rate of inc. of rotational KE, _plus_ rate
>> of power dissipation by the fan, plus rate of input of energy into
>> stretching bungee, plus rate of inc. of body KE as it moves along the slide.
>>
>> After the finish there's a further dissipation of energy (work to do)
>> = rate of inc. in bodily KE in moving from stasis towards the catch.
>>
>> In the short distance before the catch there's a further energy
>> dissipation term (more work to do)
>> = rate of decr. in bodily KE to bring the body to a halt before moving
>> back up the slide.
>>
>
> Hey Carl, I felt I was informing the 'debate' between KC and PS about
> the difference between KC's power (rate at which rower does work on
> the handle = F*v) compared with the way the erg (and perhaps PS's
> software) calculates power (rate at which KE is added to the wheel).
> As I read it, KC is using the difference in these two quantities to
> criticise PS regarding his software and PS is criticising KC for
> historical reasons. My point is there is a good reason for the
> difference, and continuing to argue about puts at least one of them in
> the wrong...
>
> All the other stuff about the difference between ergo performance and
> on-water performance is, as ever, true enough but not exactly on-the-
> point. All the erg 'cares about' is how much work you do on the
> handle, and all it displays is the fraction of that work which is
> transferred (temporarily) in the spinning flywheel.
>
> As I see it, the main cause of much of the wrangling over the buoyancy-
> or-otherwise of ergometers is the fact that they offer a 500m split
> display (plus all the derivatives of it eg distance travelled).
> Without this feature, we would probably all be happier about their
> role in rowing training - ie as a self-loading simultaneous leg-press
> and bench-pull machine with a clock on it. If one only ever set it to
> read in watts, I suspect we would use it more sensibly!
>
> Teaplant.

Don't disagree with any of that.

However, I do find the ability of a sport to believe the incredible a
little depressing. Something like 100 W goes unmeasured, unaccounted
for & ignored, yet pundits hang on the supposed significance of the odd
virtual .1 sec.

No wonder folk say erg technique can be fudged to improve readings.
Let's at least recognised openly that however the power measured,
instantaneous or average I care not, is significantly incorrect & that
the erger does a chunk of work which goes unrecorded & which is no
counterpart in rowing.

Cheers -
Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)

Teaplant

10-09-2008, 05:50 PM

> Well, it is somebody's name, James Watt, who helped develop the steam
> engine. However, you're correct that when used as a unit of power, it
> should be written 'watt'. However, to add to the confusion, the
> abbreviation of watt is large/capital 'W'.
>
> -KC

No, Watt is his name and watt is the unit. The unit is clearly
eponymous (thanks for reminding everyone though) but they are most
certainly not the same thing. There is no confusion since all such
units are written in lower case in full (coulomb, ampere, joule,
kelvin, newton) but then recover a respectful capital when
abbreviated.

litre takes a capital L in abbreviated form not because of the
pioneering work of Professor Litre, but because l looks like 1 and I
(or is it the other way round?).

Another anomaly is the prefix kilo- which is truncated to lower case k
(for example kg) to avoid confusion with K for kelvin. All other
prefixes for large multiples are upper case, with the small multiples
lower case (cm, Mbyte, ns etc)

However, 100 watts most certainly does not mean 100 members of the
Watt family (unlike 100 Watts).

argh
teaplant.

10-09-2008, 07:13 PM

Rob Collings wrote:
> On 9 Oct, 04:41, wmart...@gmail.com wrote:
>
>> Woo hoo!! I wondered if someone would answer that one...
>> SI units, if I remember correctly, are usually abbreviated with the
>> capital so
>
> Only where dervied from a name, otherwise they are lowercase. ie watts-
>> W but seconds -> s. The litre is an exception (and isn't SI) because
> NIST decided that they know best and changed it to a capital so there
> are 2 different conventions.
>
> Rob.

Indeed, milliliters is usually ml, not mL. Not sure which is correct
off hand...

-KC

10-09-2008, 07:19 PM

Teaplant wrote:
>> Well, it is somebody's name, James Watt, who helped develop the steam
>> engine. However, you're correct that when used as a unit of power, it
>> should be written 'watt'. However, to add to the confusion, the
>> abbreviation of watt is large/capital 'W'.
>>
>> -KC
>
> No, Watt is his name and watt is the unit. The unit is clearly
> eponymous (thanks for reminding everyone though) but they are most
> certainly not the same thing. There is no confusion since all such
> units are written in lower case in full (coulomb, ampere, joule,
> kelvin, newton) but then recover a respectful capital when
> abbreviated.

Uhhh... pretty much exactly what I just said above?? So why did your
paragraph start with "No"? I said his name was Watt, and I said the
unit was 'watt', and that the abbreviation is 'W'. To quote Abbot,
"same as you, SAME AS YOU!!!!" :^)

-KC

>
> litre takes a capital L in abbreviated form not because of the
> pioneering work of Professor Litre, but because l looks like 1 and I
> (or is it the other way round?).
>
> Another anomaly is the prefix kilo- which is truncated to lower case k
> (for example kg) to avoid confusion with K for kelvin. All other
> prefixes for large multiples are upper case, with the small multiples
> lower case (cm, Mbyte, ns etc)
>
> However, 100 watts most certainly does not mean 100 members of the
> Watt family (unlike 100 Watts).
>
> argh

??? Dude, we're in agreement. Go have a cup o' tea and plant a tree.

> teaplant.
>
>

10-09-2008, 07:37 PM

Christopher Kerr wrote:
> KC wrote:
>
>> paul_v_smith@hotmail.com wrote:
>>
>>> If you are asking about the "Power" unit, under the Spike Data in the
>>> Text Log view, it's the Watts being absorbed by the flywheel at that
>>> given moment.
>> No it isn't. Watts = force on the handle * velocity of the handle, at
>> any given instant. Take the handle velocity at the same moment, and the
>> handle force at that moment, and you get the Watts absorbed by the
>> flywheel at that moment. This is not the number EM reports. Check it
>> yourself, it's easy enough since EM also reports instantaneous handle
>> velocity and handle force.
>>
>
> If I have understood Paul correctly, handle force doesn't come into it,
> because EM's not measuring the power being put in by the rower but the
> power being dissipated by the flywheel. It's effectively displaying the
> rotational speed of the flywheel on a non-linear scale. Trying to show the
> instantaneous power input would probably give fairly inaccurate results,
> because you're multiplying a second derivative by a first derivative - any
> limitations in the resolution of the primary sensor would be magnified
> massively.

Before anyone gets too detailed in their theories here, he/she ought to
go try out EM. Paul will (at least used to) give you a free license to
try it for a week or month or something like that. Then you can see
what it's all about (presuming you can get your erg next to a pc of some
sort... he had issues with some laptops back when I was doing it, but I
think he's worked that out...) All you need is a mini-jack audio cable
from the erg to the PC's sound card, and an adapter for erg wire to
audio wire connection, available from electronics supply stores like
Radio Shack in the States.

EM does not and can not measure force on the handle. It calculates it
based on the delta omega of the flywheel, and the flywheel's inertial
properties. It comes quite close to reality though. I hooked up a
strain gauge and measured force and the two were close. I think the
only difference was attributable to the bungee tension. I also rigged
up a pulley system and dropped weights of known mass, pulling on the
ergo chain, and the force reported by EM was the weight of the mass
minus the bungee tension plus or minus a bit. This was tough to do
given the delay EM has (had?) before registering any values on the first
stroke.

So given that the calculated force is pretty close to reality, and
Newton's third law applies, the instantaneous power must equal the force
reported by EM multiplied by the handle velocity reported by EM (also
checked & verified by me to be "pretty close" to reality. I don't have
the exact data any more.) Heck it must equal this not only because of
Newton's 3rd, but mainly since those values must be derived from the
power in the first place! Anyway, there's no other definition of
"instantaneous power" that I can think of. Also, the curve should go
negative on the recovery since the flywheel is loosing power then, and,
IIRC it doesn't (this part I'm not sure about though, it's been a while
since I toyed with EM).

It's very likely that I've totally misunderstood what the numbers EM
reports are supposed to be, and I'm in the wrong. But until someone can
explain it to me, I'm confident in what I've said. So if you disagree,
please explain it to me. I'm not out to insult Paul. I just want to
understand what those units are, and if I've made a mistake.

-KC

wmartind@gmail.com

10-09-2008, 08:36 PM

On Oct 10, 7:19 am, kc <kc_n...@sonic.net> wrote:
> Teaplant wrote:
> >> Well, it is somebody's name, James Watt, who helped develop the steam
> >> engine. However, you're correct that when used as a unit of power, it
> >> should be written 'watt'. However, to add to the confusion, the
> >> abbreviation of watt is large/capital 'W'.
>
> >> -KC
>
> > No, Watt is his name and watt is the unit. The unit is clearly
> > eponymous (thanks for reminding everyone though) but they are most
> > certainly not the same thing. There is no confusion since all such
> > units are written in lower case in full (coulomb, ampere, joule,
> > kelvin, newton) but then recover a respectful capital when
> > abbreviated.
>
> Uhhh... pretty much exactly what I just said above?? So why did your
> paragraph start with "No"? I said his name was Watt, and I said the
> unit was 'watt', and that the abbreviation is 'W'. To quote Abbot,
> "same as you, SAME AS YOU!!!!" :^)
>
> -KC
>
>
>
> > litre takes a capital L in abbreviated form not because of the
> > pioneering work of Professor Litre, but because l looks like 1 and I
> > (or is it the other way round?).
>
> > Another anomaly is the prefix kilo- which is truncated to lower case k
> > (for example kg) to avoid confusion with K for kelvin. All other
> > prefixes for large multiples are upper case, with the small multiples
> > lower case (cm, Mbyte, ns etc)
>
> > However, 100 watts most certainly does not mean 100 members of the
> > Watt family (unlike 100 Watts).
>
> > argh
>
> ??? Dude, we're in agreement. Go have a cup o' tea and plant a tree.
>
> > teaplant.

Ok so I was off a bit in some of my units.. mea culpa.
http://ess.nrcan.gc.ca/pubs/scipub/guide/abbrev/listgen_e.php
is the result of googling "systeme internationale canada" - an
alphabetic listing of abbreviations expected in scientific
publications according to the Govt of Canukistan..
If I ever prep anything for sci-pub again, I won't try to go from
memory... Why remember stuff you can look up?
W

10-09-2008, 08:51 PM

wmartind@gmail.com wrote:
> Why remember stuff you can look up?

I love it.

That oughtta be the motto for a school of engineering somewhere. We
need a Latin translation!!! ;^)

-KC

paul_v_smith@hotmail.com

10-10-2008, 01:40 AM

On Oct 9, 12:51 pm, KC <kc_n...@sonic.net> wrote:
> wmart...@gmail.com wrote:
> > Why remember stuff you can look up?
>
> I love it.
>
> That oughtta be the motto for a school of engineering somewhere. We
> need a Latin translation!!! ;^)
>
> -KC

"Quare memor effercio vos can intueor?"

I have no idea how the Power (watts) could go negative, it can go to
zero when stationary, but if it's rotating, it's dissipating energy
and that is what is being expressed in the plot.

- Paul Smith

10-10-2008, 06:51 AM

paul_v_smith@hotmail.com wrote:
> On Oct 9, 12:51 pm, KC <kc_n...@sonic.net> wrote:
>> wmart...@gmail.com wrote:
>>> Why remember stuff you can look up?
>> I love it.
>>
>> That oughtta be the motto for a school of engineering somewhere. We
>> need a Latin translation!!! ;^)
>>
>> -KC
>
> "Quare memor effercio vos can intueor?"
>
> I have no idea how the Power (watts) could go negative, it can go to
> zero when stationary, but if it's rotating, it's dissipating energy
> and that is what is being expressed in the plot.
>
> - Paul Smith

If the wheel is accelerating, net power flow is positive. If the wheel
is decelerating, net power flow is negative.

-KC

Chris Kerr

10-10-2008, 10:15 AM

paul_v_smith@hotmail.com wrote:
> On Oct 9, 12:51 pm, KC <kc_n...@sonic.net> wrote:
>> wmart...@gmail.com wrote:
>>> Why remember stuff you can look up?
>> I love it.
>>
>> That oughtta be the motto for a school of engineering somewhere. We
>> need a Latin translation!!! ;^)
>>
>> -KC
>
> "Quare memor effercio vos can intueor?"
>
> I have no idea how the Power (watts) could go negative, it can go to
> zero when stationary, but if it's rotating, it's dissipating energy
> and that is what is being expressed in the plot.
>
> - Paul Smith

"Some people called Romanes they go the 'ouse"?

How about:
"Libre inscriptum, non memorandum"
"When something is written in a book, you don't need to remember it"

paul_v_smith@hotmail.com

10-10-2008, 03:25 PM

On Oct 9, 10:51 pm, KC <kc_n...@sonic.net> wrote:
> paul_v_sm...@hotmail.com wrote:
> > On Oct 9, 12:51 pm, KC <kc_n...@sonic.net> wrote:
> >> wmart...@gmail.com wrote:
> >>> Why remember stuff you can look up?
> >> I love it.
>
> >> That oughtta be the motto for a school of engineering somewhere. We
> >> need a Latin translation!!! ;^)
>
> >> -KC
>
> > "Quare memor effercio vos can intueor?"
>
> > I have no idea how the Power (watts) could go negative, it can go to
> > zero when stationary, but if it's rotating, it's dissipating energy
> > and that is what is being expressed in the plot.
>
> > - Paul Smith
>
> If the wheel is accelerating, net power flow is positive. If the wheel
> is decelerating, net power flow is negative.
>
> -KC

No Kidding? So "Power" and "Net Power" are the same thing?! My
Goodness! I had even typed a sentence regarding the absence of a "Net
Power" plot (then figured it was not needed.), though we do have a Net
Torque plot that will go below the X axis once the applied force is no
longer capable of accelerating the flywheel; IOW, when applied torque
<= Drag torque on the axle. More magic. [:o)

Rec.Sport.Rifle entry: (gotta keep this interesting for myself
somehow.)
The barrel lapping when very well, each 10 round string improved in
consistency with outliers explained by my errors mostly. Of course
there was no particular care put into assembling the ammo being used
as would normally be the case (hence the "mostly"). In the end I went
back to the Standard Load that the rifle favors, fired 3 rounds to
determine the new POI, made the required adjustment and fired a single
"proof" round for confirmation and viola, as close to dead center as
could be expected. Very pleased with the result. Also, the "younger
twin" rifle (.22LR) proved to be most excellent at 100yd, the best
part was that the bullet could actually be watched through the scope
on it's travel downrange, and at $0.02/round it's much more affordable
to shoot, while simulating much longer ranges for the high power
rifle. Practice, practice, practice....

- Paul Smith

wmartind@gmail.com

10-10-2008, 06:04 PM

On Oct 10, 8:51 am, KC <kc_n...@sonic.net> wrote:
> wmart...@gmail.com wrote:
> > Why remember stuff you can look up?
>
> I love it.
>
> That oughtta be the motto for a school of engineering somewhere. We
> need a Latin translation!!! ;^)
>
> -KC

Hmm. I rephrased something Einstein is supposed to have said, and he
prolly wasn't the first.
W

10-11-2008, 12:58 AM

paul_v_smith@hotmail.com wrote:
> On Oct 9, 10:51 pm, KC <kc_n...@sonic.net> wrote:
>> paul_v_sm...@hotmail.com wrote:
>>> On Oct 9, 12:51 pm, KC <kc_n...@sonic.net> wrote:
>>>> wmart...@gmail.com wrote:
>>>>> Why remember stuff you can look up?
>>>> I love it.
>>>> That oughtta be the motto for a school of engineering somewhere. We
>>>> need a Latin translation!!! ;^)
>>>> -KC
>>> "Quare memor effercio vos can intueor?"
>>> I have no idea how the Power (watts) could go negative, it can go to
>>> zero when stationary, but if it's rotating, it's dissipating energy
>>> and that is what is being expressed in the plot.
>>> - Paul Smith
>> If the wheel is accelerating, net power flow is positive. If the wheel
>> is decelerating, net power flow is negative.
>>
>> -KC
>
> No Kidding? So "Power" and "Net Power" are the same thing?! My

I don't follow you here, between what you write, and then your implied
sarcasm, I'm not sure if you actually agree or disagree with the
statement you just made.

> Goodness! I had even typed a sentence regarding the absence of a "Net
> Power" plot (then figured it was not needed.), though we do have a Net
> Torque plot that will go below the X axis once the applied force is no
> longer capable of accelerating the flywheel; IOW, when applied torque
> <= Drag torque on the axle. More magic. [:o)

You have stated that the instantaneous power values EM reports in the
spike data are the power dissipated by the ergo. While I doubt that's
actually the case, even if it is correct it's quite a useless thing to
report. A rower cares about the power he/she is supplying (either
instantaneous or averaged over a storke). The power the rower supplies
has two parts, power from viscous forces on the flywheel, and power from
inertial forces of the flywheel. So,

P_rower = P_viscous + P_inertia

If all EM reports is the dissipated power, then that's only P_viscous,
and ignores the inertial effects. (BTW in P_visc, I'm grouping power to
pump air, and drag-power from bearing and aero friction). So reporting
only the dissipated power is pretty meaningless to a rower, except maybe
during the recovery when P_rower is zero and P_visc = -P_inert.

> Rec.Sport.Rifle entry: (gotta keep this interesting for myself
> somehow.)

Here is a group of people who probably care:
http://groups.google.com/group/rec.guns/topics?lnk

-KC

Carl Douglas

10-22-2008, 06:33 PM

Carl Douglas wrote:
< snipped >
>
> However, I do find the ability of a sport to believe the incredible a
> little depressing. Something like 100 W goes unmeasured, unaccounted
> for & ignored, yet pundits hang on the supposed significance of the odd
> virtual .1 sec.
>
> No wonder folk say erg technique can be fudged to improve readings.
> Let's at least recognised openly that however the power measured,
> instantaneous or average I care not, is significantly incorrect & that
> the erger does a chunk of work which goes unrecorded & which is no
> counterpart in rowing.
>
> Cheers -
> Carl
>

I was surprised that my posting, above, generated not even a whisper of
a response from RSR's erg-warriors.

Doesn't it matter to them that >100W, typically, of the erger's average
work rate goes unmeasured?

Why are they, when claiming that ergs accurately measure the work done,
content to turn so blind an eye to this inconvenient elephant leaving
his mark in a corner of their room?

Cheers -
Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)

kdavies@kidare.com

10-23-2008, 09:12 AM

On 22 Oct, 18:33, Carl Douglas <c...@carldouglas.co.uk> wrote:
> Carl Douglas wrote:
>
> < snipped >
>
>
>
> > However, I do find the ability of a sport to believe the incredible a
> > little depressing. Something like 100 W goes unmeasured, unaccounted
> > for & ignored, yet pundits hang on the supposed significance of the odd
> > virtual .1 sec.
>
> > No wonder folk say erg technique can be fudged to improve readings.
> > Let's at least recognised openly that however the power measured,
> > instantaneous or average I care not, is significantly incorrect & that
> > the erger does a chunk of work which goes unrecorded & which is no
> > counterpart in rowing.
>
> > Cheers -
> > Carl
>
> I was surprised that my posting, above, generated not even a whisper of
> a response from RSR's erg-warriors.
>
> Doesn't it matter to them that >100W, typically, of the erger's average
> work rate goes unmeasured?
>
> Why are they, when claiming that ergs accurately measure the work done,
> content to turn so blind an eye to this inconvenient elephant leaving
> his mark in a corner of their room?
>
> Cheers -
> Carl
>
> --
> Carl Douglas Racing Shells -
> Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
> Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
> Find: http://tinyurl.com/2tqujf
> Email: c...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
> URLs: www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)

I was contemplating it. My hand is forced...

I recently tried putting some industrial-sized fixed castors on the
bottom of my model C to see what effect it would have on my technique
and scores. The thing I noticed immediately was the change around the
catch. I had to consciously draw the erg up under me whereas on a
fixed erg I could let myself roll up into the catch under my own
moment. I think this difference has 2 consequences:
1. On a sliding erg/boat, the stroke is shorter in length than on a
fixed erg since the body has no momentum going into the catch. This
resulted in worse splits than on a fixed erg.
2. On a fixed erg, the extra length produces more tension in the knees
and ankles which act as springs and help mitigate the extra effort
required to change momentum at the catch.

So at lower rates (= lower momentum) I am not sure that the difference
in required effort is that great.
At higher rates, things work much more in favour of the sliding erg. I
could rate 40 no problem with corresponding improvement in splits.

These are just my impressions. Nothing scientific.
Kit

paul_v_smith@hotmail.com

10-23-2008, 11:57 AM

On Oct 22, 10:33 am, Carl Douglas <c...@carldouglas.co.uk> wrote:
> Carl Douglas wrote:
>
> < snipped >
>
>
>
> > However, I do find the ability of a sport to believe the incredible a
> > little depressing. Something like 100 W goes unmeasured, unaccounted
> > for & ignored, yet pundits hang on the supposed significance of the odd
> > virtual .1 sec.
>
> > No wonder folk say erg technique can be fudged to improve readings.
> > Let's at least recognised openly that however the power measured,
> > instantaneous or average I care not, is significantly incorrect & that
> > the erger does a chunk of work which goes unrecorded & which is no
> > counterpart in rowing.
>
> > Cheers -
> > Carl
>
> I was surprised that my posting, above, generated not even a whisper of
> a response from RSR's erg-warriors.
>
> Doesn't it matter to them that >100W, typically, of the erger's average
> work rate goes unmeasured?
>
> Why are they, when claiming that ergs accurately measure the work done,
> content to turn so blind an eye to this inconvenient elephant leaving
> his mark in a corner of their room?
>
> Cheers -
> Carl
>

Perhaps because it's nothing "like 100 watts" that goes unaccounted
for, and we've been down this road (Slide) before. One way or the
other, the system is in equilibrium with the flywheel dissipating the
vast majority (should be "all") the input energy from the rower. I
suppose there could be a good bit being absorbed by the ground/rubber
foot interface for those that use the straps to arrest the body
momentum at the finish, but that's a bad technical flaw which should
be corrected.

On slides, it's easy to see, as we can know just what distance the
seat should move, WRT the ground, based on the Mass of the Erg Vs Mass
of the Rower, anything outside of that would indeed have a counterpart
in a boat, and none of it would be good.

I had a rower get quite snippy recently when they asked "So you want
us to bring the rate up by getting the blade faster through the water,
right?", to which I answered "No, why would I want you to shorten your
drive like that? You can't do anything to accelerate the system
toward the finish line unless your blade is in the water, so if you
shorten that time you will lose the benefit of increasing the rate."
Though, based on observations, it would appear that one may be able to
reduce the physical length of the drive while maintaining the temporal
length as the rate comes up, along with a corresponding increase in
Avg system speed.

Kit had some rather insightful things to offer on the subject, though
his statement about being able to "rate 40 no problem with a
corresponding drop in pace" is not quite accurate, or I suppose that
he could do a 2k on slides R40 and set a new PR "no problem", but that
hasn't happened yet for anyone with a consistent performance record
for the standard 2k test. All Ergs are "dynamic", they simply vary in
the magnitude of visible dynamism. [;o)

- Paul Smith