Return-Path: Sender: (Marvin Kaye) To: lml Date: Sun, 05 Jan 2003 21:46:30 -0500 Message-ID: X-Original-Return-Path: Received: from imo-d06.mx.aol.com ([205.188.157.38] verified) by logan.com (CommuniGate Pro SMTP 4.0.3) with ESMTP id 1945733 for lml@lancaironline.net; Sun, 05 Jan 2003 21:31:23 -0500 Received: from Sky2high@aol.com by imo-d06.mx.aol.com (mail_out_v34.13.) id q.78.34b13bc2 (3310) for ; Sun, 5 Jan 2003 21:31:13 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <78.34b13bc2.2b4a4471@aol.com> X-Original-Date: Sun, 5 Jan 2003 21:31:13 EST Subject: Re: [LML] Front oleo castering X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_78.34b13bc2.2b4a4471_boundary" X-Mailer: AOL 8.0 for Windows US sub 460 --part1_78.34b13bc2.2b4a4471_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 1/5/2003 5:57:30 PM Central Standard Time, ian.crowe@sympatico.ca writes: > I have had my front oleo rebuilt by Lancair and it appears that it has > excessive "Stiction" that is a combination of inherent stickiness and > friction. Ian, For a while, Lancair was experimenting with 30 weight fork oil instead of the usual 20 wt. I had to go back to the 20 wt. because the 30 wt became very stiff in the cold weather. Consider that a 200 pound pilot with his belt buckle at BL18 provides a moment of 3600 inch pounds whilst fuel being used from a full wing tank out at about BL110 is equivalent to about 5 gallons of fuel (3600/110=32 pounds). If you don't have a system that draws evenly from both wings, assuming starting with full tanks and flying solo, draw the first 10 gallons from the left tank and then 5 from the right, 5 from the left etc. Assume that 17 gallons of fuel fills the wing from BL50 to BL115 and that the use of 3 gallons moves the "CG" in about 10 inches. So, for a wing: 060x18=1080 070x18=1260 080x18=1440 090x18=1620 100x18=1800 110x12=1320 ---------------------- 8520 moment And a 1/4 tank would have a moment of about 1500. pilot and left wing - 1/4 right wing = 3600 + 8520 - 1500 = 10620 Say the aileron lift is at BL125, then 10620/125=85 pounds of lift needed at the aileron. Scott Krueger N92EX --part1_78.34b13bc2.2b4a4471_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 1/5/2003 5:57:30 PM Central Standard Time, ian.crowe@sympatico.ca writes:

I have had my front oleo rebuilt by Lancair and it appears that it has excessive "Stiction"  that is a combination of inherent stickiness and friction.


Ian,

For a while, Lancair was experimenting with 30 weight fork oil instead of the usual 20 wt.  I had to go back to the 20 wt. because the 30 wt became very stiff in the cold weather.

<I am inclined to think that the situation should be avoided by better handling of the side to side fuel consumption.>

Consider that a 200 pound pilot with his belt buckle at BL18 provides a moment of 3600 inch pounds whilst fuel being used from a full wing tank out at about BL110 is equivalent to about 5 gallons of fuel (3600/110=32 pounds).  If you don't have a system that draws evenly from both wings, assuming starting with full tanks and flying solo, draw the first 10 gallons from the left tank and then 5 from the right, 5 from the left etc.

Assume that 17 gallons of  fuel fills the wing from BL50 to BL115 and that the use of 3 gallons moves the "CG" in about 10 inches.  So, for a wing:
060x18=1080
070x18=1260
080x18=1440
090x18=1620
100x18=1800
110x12=1320
----------------------
             8520  moment
And a 1/4 tank would have a moment of about 1500.

pilot and left wing - 1/4 right wing = 3600 + 8520 - 1500 = 10620

Say the aileron lift is at BL125, then 10620/125=85 pounds of lift needed at the aileron.

Scott Krueger
N92EX

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