Increasing the DF

[Tim K.]

I know many have done it before but the results were not as expected:

DF as delivered on damper setting 10: 203

DF with damper and screen removed: 175 ( but higher perceived effort than above)

DF with damper in place (setting 10) but no screen: 66 ( much higher perceived effort than above)

WTF is going on?

[Tim K.]

Here is a picture of displayed DF. You can see the screen is removed but damper is in place on setting 10, which with the screen in place yields a DF of 204. This arrangement nets the highest perceived load but the lowest DF and kills reported performance.

Anyone with any suggestions as to why this is not working for me would be much appreciated.

[jamesg]

Probably a short circuit.

[Carl Watts]

Not sure why you removed the screen in the first place but with everything clean, especially the screen with a brush and soapy water you should have about 136 on setting 6 and you just leave it there.

If the DF then starts jumping about then as long as your monitor is configured to a Model D/E I would be looking at the pickup cable.

The PM4 is a very reliable monitor and as long as its on the latest version of Firmware, I never see them with an electronic fault.

[hjs]

Very high drags can,t be measured above a certain number, beyond that the drag starts at 1 again. Don,t know the details, but drags like 400 ofcourse do exist, but can,t be seen on a pm.
The same for very low drags, if you cover the air inflow.

[Tim K.]

Not sure why you removed the screen in the first place but with everything clean, especially the screen with a brush and soapy water you should have about 136 on setting 6 and you just leave it there.

If the DF then starts jumping about then as long as your monitor is configured to a Model D/E I would be looking at the pickup cable.

The PM4 is a very reliable monitor and as long as its on the latest version of Firmware, I never see them with an electronic fault.

There is nothing wrong with the PM at all. When reassembled the PM reads as it did/should.

As stated in the title, Im trying to increase drag, which was successful, however the PM isnt calculating it correctly.

Why? Because my performance continues to increase as DF increases. So far I seem to max out (with decent form) at ~45 SPM, regardless of DF. As DF increases, so does performance, all the way up to 203 (damper setting of 10). Im looking for the point where it starts to decline, simple as that. I know you like to live "in the box" but the purpose of the thread is to try to figure out how to obtain a higher than 204 DF, not live with what is considered "the norms". At 136, where you are suggesting "you just leave it there" I loose over 150 watts.

[Tim K.]

Very high drags can,t be measured above a certain number, beyond that the drag starts at 1 again. Don,t know the details, but drags like 400 ofcourse do exist, but can,t be seen on a pm.
The same for very low drags, if you cover the air inflow.

You dont happen to know what that number is do you? I dont mind modifying my machine to creep towards that number.

[hjs]

Very high drags can,t be measured above a certain number, beyond that the drag starts at 1 again. Don,t know the details, but drags like 400 ofcourse do exist, but can,t be seen on a pm.
The same for very low drags, if you cover the air inflow.

You dont happen to know what that number is do you? I dont mind modifying my machine to creep towards that number.

Sorry no, better contact c2 directly and ask.

[Carl Watts]

Why? Because my performance continues to increase as DF increases. So far I seem to max out (with decent form) at ~45 SPM, regardless of DF. As DF increases, so does performance, all the way up to 203 (damper setting of 10). Im looking for the point where it starts to decline, simple as that. I know you like to live "in the box" but the purpose of the thread is to try to figure out how to obtain a higher than 204 DF, not live with what is considered "the norms". At 136, where you are suggesting "you just leave it there" I loose over 150 watts.

Your not posting up enough information like pace and distance etc. Perhaps a bit more personal info like age and height etc.

Cannot see why you need such a high drag factor to get the performance, Elite rowers get the high performance from a LOWER DF, even lower than mine. Rob Weddels 2K WR was rumored to be at a DF of 90. Video evidence of the damper position on a clean erg would suggest most people row in the 110-130 area.

The more rowing I did the lower my DF needed to be. I started on 164 when I didn't know what I was doing and its gone down form there.

Unless your focus is all on the 500m, then a high DF is not required.

If your going at 45spm and a DF of 203 then your doing something wrong unless your at like 1:10 pace !!!!

[Tim K.]

Carl, being employed by C2 your in a position to actually provide an answer. Please feel free provide an answer to the actual question now at hand: What is the maximum DF the PM4 is capable of accurately displaying? No more info required as Im not interested in having you solve what you perceive as "my problem".

[lindsayh]

Carl, being employed by C2 your in a position to actually provide an answer. Please feel free provide an answer to the actual question now at hand: What is the maximum DF the PM4 is capable of accurately displaying? No more info required as Im not interested in having you solve what you perceive as "my problem".

Hi Tim - Carl is not an employee of C2 but just a guy with a repair business in NZ.

We had a guy at our gym with a crazy high DF habit and on relatively clean machines we would see 250 ish with the covers off on a PM4 with no problems.
(he would then do an hour @2:30) - I could never get him to go faster.
There was a guy on the UK site from South Africa who routinely took the cover off and he was reporting a bit higher - 260+ - and used to do his marathons that way.
Shawn Baker here routinely removes the cover (at altitude) and I think he gets 240-250?

[Carl Watts]

As above. You also appear to have more than "One Problem"

[jamesgo]

What is the maximum DF the PM4 is capable of accurately displaying?

As designed, just over 200. If you take bits and pieces off, the machine is no longer as designed, so will give unreliable results.

Without it's cage and volute (essential parts of the design of a centrifugal fan), flow and pressures are unpredictable. Even a chair near the machine or an open window or you rowing on it could influence flow and pressures. So drag is unpredictable under these conditions.

Anyway, what's the point of using an erg for isostatic work? Better use weights, at least the number written on them and gravity can't change.

[Tim K.]

Carl, being employed by C2 your in a position to actually provide an answer. Please feel free provide an answer to the actual question now at hand: What is the maximum DF the PM4 is capable of accurately displaying? No more info required as Im not interested in having you solve what you perceive as "my problem".

Hi Tim - Carl is not an employee of C2 but just a guy with a repair business in NZ.

We had a guy at our gym with a crazy high DF habit and on relatively clean machines we would see 250 ish with the covers off on a PM4 with no problems.
(he would then do an hour @2:30) - I could never get him to go faster.
There was a guy on the UK site from South Africa who routinely took the cover off and he was reporting a bit higher - 260+ - and used to do his marathons that way.
Shawn Baker here routinely removes the cover (at altitude) and I think he gets 240-250?

Thank you. Its nice to get a little help with out what seems to be the obligatory BS. With a bit of trial and error, removing the screen, blocking out the 4 quadrants and slowly increasing the openings I worked my way up to a DF of 253. Didnt bother going any higher than that as I was getting pretty tired doing pulls and peak output for that session was around 230.

Thanks again!

[Tim K.]

What is the maximum DF the PM4 is capable of accurately displaying?

As designed, just over 200. If you take bits and pieces off, the machine is no longer as designed, so will give unreliable results.

Without it's cage and volute (essential parts of the design of a centrifugal fan), flow and pressures are unpredictable. Even a chair near the machine or an open window or you rowing on it could influence flow and pressures. So drag is unpredictable under these conditions.

Anyway, what's the point of using an erg for isostatic work? Better use weights, at least the number written on them and gravity can't change.

I didnt ask what the DF of a factory C2 blower assembly was, I asked if anyone knew what DF the PM4 was capable of accurately displaying (see quote above).

A cage and volute are not essential parts of a centrifugal fan, A volute is only required if high side air control is desired (like in common HVAC systems) which is why the rower does not have a volute. The screen/cage is simply there to help reduce airflow (drag factor) and prevent loss/injury of digits. Removal of the screen and damper in a typical indoor setting will not result in unstable/unpredictable flow characteristics.

Whats the point? Concept2 thought there was some point to it.