DIYAPASON-L Digest #142 - Tuesday, August 22, 2000
Re: Feed Line Sizing [was New room for the organ...]
  by "Bernard C. Nordmann" <>

(back) Subject: Re: Feed Line Sizing [was New room for the organ...] From: "Bernard C. Nordmann" <> Date: Mon, 21 Aug 2000 09:36:47 -0500   At 12:22 PM 8/16/00 -0500, you wrote: >> Run 12" pipe between the two? 6" ? > >If you need the capacity of one 12" pipe you will need at least >four 6" jobs to get the equivalent amount of air. >Why 'at least'? Because of frictional losses in the smaller windlines.   It's the cross sectional area of the lines which determines the air carrying capacity, so four 6" lines are needed just for the basic air moving.   To handle air friction, an additional wind line area is needed. In practice, however, most people (I believe) ignore the air friction contribution. I did in designing for my 3/13 Wurlitzer, using a 12" line for the 5 ranks in the main chamber (originally all flue pipes - bigger users of air) and relay and a 10" line for the 8 rank solo chamber (6 = ranks of reeds).   Both chambers have a rock solid supply of wind; I can't get the reservoir/regulators to sag more than a tiny amount.   Bernie Nordmann, St. Louis