Model B and PM2+ from salvage.

Maintenance, accessories, operation. Anything to do with making your erg work.
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Tees Erg Fairy
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Model B and PM2+ from salvage.

Post by Tees Erg Fairy » October 16th, 2017, 3:17 pm

Hi all,

I'm in the process of resurrecting an old Model B I saved from the boathouse skip, and it has no monitor. I've plugged in an old PM2+ monitor, also salvaged, and it seems to work but the drag factor is waaaay off. I gather this is to be expected, which makes me wonder the following:

1. Does anyone know what the equivalent drag factors on a Model C or D are? Is there a comparison chart somewhere still? Links to the old one I've found searching here no longer lead to it.

2. If the drag factor isn't the same, how accurate will the splits and distance be? Is it best just to use the rate count and timer for steady state work and ignore the rest entirely, or is there - again - a comparison chart somewhere?

Thanks!

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Citroen
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Re: Model B and PM2+ from salvage.

Post by Citroen » October 17th, 2017, 2:50 am

Search on here for some of the posts from Bob Spenger, I think he had a model B before he upgraded to model C/D then to a dynamic.

This thread may help: viewtopic.php?f=10&t=87744&p=288461&hil ... el#p288173

search.php?st=0&sk=t&sd=d&sr=posts&keyw ... thor_id=15

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c2jonw
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Re: Model B and PM2+ from salvage.

Post by c2jonw » October 17th, 2017, 8:09 am

Tees- What sort of numbers are you seeing for the drag factor? The Bs had a pretty high drag range, and when in the small sprocket with the damper wide open the loading was quite heavy, leading us to offering an inlet cover that lowered the range quite a bit. Here's a rough comparison chart: http://www.concept2.com/files/pdf/us/in ... arison.pdf
Note that Drag Factor is a numerical value of the rate of deceleration of the flywheel and is unaffected by the sprocket. The sprocket size changes your mechanical advantage over the drag and momentum of the flywheel, thus changing the feel of the pull. C2JonW
73 year old grandpa living in Waterbury Center, Vermont, USA
Concept2 employee 1980-2018! and what a long, strange trip it's been......

Tees Erg Fairy
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Re: Model B and PM2+ from salvage.

Post by Tees Erg Fairy » October 18th, 2017, 2:56 pm

Hi Jon. About 170 using the bigger sprocket and with the damper closed. It doesn't feel like 170 though, it feels more like 100ish. As a Lwt woman I usually row on about 110 (to emulate my low geared adaptive-rig single scull) and it feels lighter than that, hence wondering if the splits/metres will be unreliable as well.

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c2jonw
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Re: Model B and PM2+ from salvage.

Post by c2jonw » October 18th, 2017, 3:48 pm

About 170 using the bigger sprocket and with the damper closed. It doesn't feel like 170 though, it feels more like 100ish. As a Lwt woman I usually row on about 110
Tees- That all sounds about right so your scores will be comparable. Even though the drag is higher than you are used to, it feels lighter because you are on the bigger sprocket, which has one tooth more than the C/D/E sprocket. C2JonW
73 year old grandpa living in Waterbury Center, Vermont, USA
Concept2 employee 1980-2018! and what a long, strange trip it's been......

Tees Erg Fairy
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Re: Model B and PM2+ from salvage.

Post by Tees Erg Fairy » October 19th, 2017, 8:17 am

That makes perfect sense. Thanks Jon! :mrgreen:

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