Drag factor changed from 136 to 227 on the same damper

[BodyResults]

I did a 500 meter row on Oct 9 on damper setting 6. The log said the drag factor was 136.

Then I did another 500 meter row on Oct 12 on the same damper setting of 6 and the log said the drag factor was 227.

I can't image the drag factor could really change like this. Are the drag factors listed in the a long usually accurate? Any idea why there would be such a variance?

Thanks

[Tony Cook]

I did a 500 meter row on Oct 9 on damper setting 6. The log said the drag factor was 136.

Then I did another 500 meter row on Oct 12 on the same damper setting of 6 and the log said the drag factor was 227.

I can't image the drag factor could really change like this. Are the drag factors listed in the a long usually accurate? Any idea why there would be such a variance?

Thanks

Is it the same machine? Is it in the same place with the same conditions?
If so someone more knowledgable will have to help.
If not, then different machines have different DFs with the same damper setting and the proximity of an object to the fan, or even a draught can have an effect.

[JaapvanE]

I did a 500 meter row on Oct 9 on damper setting 6. The log said the drag factor was 136.

Sounds like a plausible setting on a young machine.

Then I did another 500 meter row on Oct 12 on the same damper setting of 6 and the log said the drag factor was 227.

That is way off. 230 to 235 is what it should read when the damper is at 10 for a new machine. Collecting dust should have an opposite effect: drag going down for the same damper setting. Did you do anything abnormal? Is something causing extra drag (something that is hampering the flywheel to move, like a piece of paper that is inside the cage, some issues with bearings)? Does the rower still feel OK, or does it feel heavy?

I can't image the drag factor could really change like this. Are the drag factors listed in the a long usually accurate? Any idea why there would be such a variance?

I measure DF and its behaviour quite accurately, as I am the developer of Open Rowing Monitor, and we structurally compare dragfactor to the PM5. Environmental conditions usually affect drag within 2 to 3 DF points across training sessions. Within a session, at DF135, it can vary 2 to 3 DF points as well, but these are small peaks and it usually is quite stable.

[gvcormac]

How was the log captured? ErgData? Most likely a glitch.

Use the PM5 "drag factor" to see what it really is.

[Carl Watts]

You have to be very careful with things like fans being turned on or off and pointing directly into the side of the Concept 2 fan housing, this makes a significant difference in the Drag Factor, otherwise it changes very little over the pace/rating changes maybe 2 or 3 variance.

[BodyResults]

Thanks for the replies everyone.

This is a Model E in my home. No change in position no external fans involved.

I did use Ergdata on my phone to set the PM5 distance to row both times.

I just went down and checked what the PM5 said for drag doing a few strokes. It said 138. Then I used Ergdata to set it to row 100 meters and did the row. This time Ergdata said the drag was 138.

I really didn't noticed there was any physical difference in feeling of the amount of drag from the previous rows.

Perhaps the Ergdata recorded a glitch?

Doug

[JaapvanE]

I just went down and checked what the PM5 said for drag doing a few strokes. It said 138. Then I used Ergdata to set it to row 100 meters and did the row. This time Ergdata said the drag was 138.

I really didn't noticed there was any physical difference in feeling of the amount of drag from the previous rows.

Perhaps the Ergdata recorded a glitch?

I would assume so. A drag of 227 instead of 136, you'll feel the difference (the flywheel will feel very heavy).

[Ombrax]

A drag of 227 instead of 136, you'll feel the difference (the flywheel will feel very heavy).

I agree with this ^^^^

For the same "normal stroke effort" there will be a dramatic difference at the handle between 227 and 136 which the user should notice.

[Dangerscouse]

I just went down and checked what the PM5 said for drag doing a few strokes. It said 138. Then I used Ergdata to set it to row 100 meters and did the row. This time Ergdata said the drag was 138.

I really didn't noticed there was any physical difference in feeling of the amount of drag from the previous rows.

Perhaps the Ergdata recorded a glitch?

I would assume so. A drag of 227 instead of 136, you'll feel the difference (the flywheel will feel very heavy).

There will be a very notable difference between 136 and 227. I can feel the difference when the drag factor is changed by +10.