Force curve and drag factor

zen cohen · Post by **zen cohen** » October 4th, 2008, 6:32 pm

Are these two elements related? IOW, should I perhaps play with DF until I see a force curve that yields more of a left-leaning haystack? (I get the impression that this is generally the more desirable distribution of force; true?)

FWIW my pieces run usually btw 30 and 45 minutes and I notice my force curves tend to be pretty smooth, but graudual and symmetrical (kind of a low evenly sloping haystack). I've been dropping my DF lately, usually to under 100, from about 120 before. Don't know if it's yielding better results but it feels more efficient. (BTW, I don't do many 2ks but I recently did a PB 7:35 on a clogged-up Model D that showed a DF of 60 -- yeah, SIXTY -- at damper 10.)

TIA!

johnlvs2run · Post by **johnlvs2run** » October 4th, 2008, 8:49 pm

You're doing great to get a PB at a 60 drag factor!

The best force curve is one that is full throughout, especially on both ends and with no ragged edges or slumps.

It is easier to be full on the front end than the finish, easier to get a full force curve with a high drag factor, a faster pace, higher meters per stroke, and on slides.

It takes better technique and focus to get a full force curve with a low drag factor, a slower pace, and less meters per stroke, though these are productive to accomplish.

zen cohen · Post by **zen cohen** » October 5th, 2008, 12:17 am

John Rupp wrote:You're doing great to get a PB at a 60 drag factor!

The best force curve is one that is full throughout, especially on both ends and with no ragged edges or slumps.

It is easier to be full on the front end than the finish, easier to get a full force curve with a high drag factor, a faster pace, higher meters per stroke, and on slides.

It takes better technique and focus to get a full force curve with a low drag factor, a slower pace, and less meters per stroke, though these are productive to accomplish.

Re the DF, even though it showed 60 I wonder if when a machine is so gunked up the DF reading is reliable.

I usually don't look at the force curve but given my poor technique I was surprised it was so smooth. Unfortunately it's pretty weak, too. Like little anthills.

johnlvs2run · Post by **johnlvs2run** » October 5th, 2008, 1:43 am

The length of the curve reflects the time of the drive. The curve is longer when the drag factor is higher, because the drive is slower and takes more time to complete. The height is reflective of the changing speed of the fan. If you're not going very fast or using a low drag factor then the curve is lower and that's fine.

I've been rowing with the mesh off, and enjoying the smooth full sound of the fan.

It occurs to me that this is a quick and easy way to clean out a lot of dust from inside the erg, without removing the cage. All that is needed is a screwdriver to remove the mesh, wipe off both sides with a damp washcloth, spin the fan a few times so any clumps drop out, put the mesh back on the cage and then check to see the difference.