X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 5.1c.3) with ESMTP id 1352790 for flyrotary@lancaironline.net; Mon, 28 Aug 2006 14:10:33 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m21.mx.aol.com (mail_out_v38_r7.6.) id q.429.8f3ebd8 (40522) for ; Mon, 28 Aug 2006 14:09:49 -0400 (EDT) From: Lehanover@aol.com Message-ID: <429.8f3ebd8.32248b6d@aol.com> Date: Mon, 28 Aug 2006 14:09:49 EDT Subject: Re: [FlyRotary] Re: OT: Gardenhose as level To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1156788589" X-Mailer: 9.0 Security Edition for Windows sub 5331 X-Spam-Flag: NO -------------------------------1156788589 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/28/2006 1:15:18 P.M. Eastern Daylight Time, echristley@nc.rr.com writes: Finn Lassen wrote: > Only vaugely rotary related... > > I'm driving myself nuts trying to build this thing level to within 1/8 > to 1/4" ! > > I'm using a gardenhose, terminating in clear PVC tubing at each end, > to get reference points at the four corners. > > The thing is that the level varies 1/2" or more over hours. The commercial versions that I have seen use all clear plastic tubing for the full run, so you can be sure that there are no bubbles in the hose. If a bubble sits in one place a while it tends not to move without more than nominal pressure changes. It dries the wall of the hose and surface tension takes over. If the tubing gets a slug of air between two low spots, that forms a "P" trap like the one under the sink, and the water column will not move at all. It is also good to keep the ends of the clear tubing mounted higher than you highest construction and measure down from the fluid level. That keeps much of the tubing running up hill and reduces bubble entrainment. Unless the tubing runs are short as in the race car setup, they tend to be a pain to use. Worse if left at ground level (pun). Lynn E. Hanover -------------------------------1156788589 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 8/28/2006 1:15:18 P.M. Eastern Daylight Time,=20 echristley@nc.rr.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Finn=20 Lassen wrote:

> Only vaugely rotary related...
>
> I= 'm=20 driving myself nuts trying to build this thing level to within 1/8
>= ; to=20 1/4" !
>
> I'm using a gardenhose, terminating in clear PVC tu= bing=20 at each end,
> to get reference points at the four=20 corners.
>
> The thing is that the level varies 1/2" or more o= ver=20 hours.
 
The commercial versions that I have seen use all clear plastic tubing f= or=20 the full run, so you can be sure that there are no bubbles in the hose. If a= =20 bubble sits in one place a while it tends not to move without more than nomi= nal=20 pressure changes. It dries the wall of the hose and surface tension takes ov= er.=20 If the tubing gets a slug of air between two low spots, that forms a "P" tra= p=20 like the one under the sink, and the water column will not move at all.
 
It is also good to keep the ends of the clear tubing mounted highe= r=20 than you highest construction and measure down from the fluid level. That ke= eps=20 much of the tubing running up hill and reduces bubble entrainment. Unless th= e=20 tubing runs are short as in the race car setup, they tend to be a pain to us= e.=20 Worse if left at ground level (pun).
 
 
Lynn E. Hanover 
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