X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 01 Jan 2008 15:49:33 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m28.mx.aol.com ([64.12.137.9] verified) by logan.com (CommuniGate Pro SMTP 5.2c4) with ESMTP id 2626271 for lml@lancaironline.net; Mon, 31 Dec 2007 16:23:37 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.9; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m28.mx.aol.com (mail_out_v38_r9.3.) id q.d4e.1cee6211 (65097) for ; Mon, 31 Dec 2007 16:22:49 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Mon, 31 Dec 2007 16:22:49 EST Subject: Re: [LML] fuel question 235/320/360 X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1199136169" X-Mailer: AOL 9.0 VR sub 5006 X-Spam-Flag: NO -------------------------------1199136169 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/31/2007 1:39:57 P.M. Central Standard Time, randylsnarr@yahoo.com writes: I am looking for feedback from those who pull fuel directly from their wings that do not have slosh boxes installed. My fuel pickups are in the typical place (BL 50 about 2/3 of the way back between the front and rear spar). I am contemplating changing the fuel system with a 3 way valve to pull from Left Main and Right tanks. I would be very interested to know if you ever unport the fuel and under which conditions it happens if ever. Randy, I can only answer your question theoretically. I believe in the simple system pretty much as designed for the wee Lancairs. As such, the wings can be completely emptied into the header tank while in level flight (down to the last cupful), thus maximizing the available fuel onboard. Drawing directly from a wing without a slosh chamber means that at some lesser fuel level, the wing feeding the engine can unport via a slip, skid, uncoordinated flight, high pitch angle (extended climb or descent) or a spin. The fuel level may be different for each of the conditions listed and it is doubtful if any were tested whilst the wings were off the airplane when it is easy to check at certain pitch angles. Let's see, how about a Vx, Vy or missed approach climb out with a standard rate turn (albeit slightly uncoordinated) away from the 1/4 filled wing? Does this mean the checklists for takeoffs, landings and approaches contains a check off to switch to the wing with a 1/2 or better fuel quantity? So many bad possibilities are extant. Some planes that have 3-way selectors and pumps that are utilized to keep the header full, where the header is used for takeoff and landing or reserve only. The selector valve is considered a backup in case a pump (or the complete electrical system) should fail. Of course, others (like myself) keep the header tank full (>8 gal) at all times (engine sole fuel source) and have pre-made the decision that should they note a pump failure, the "nearest airport" GPS function is activated. The safest way to reach your destination is with everything working - even if it takes a day or two longer. We look at the header as the main fuel tank and the wings merely as aux tanks. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Darwinian culling phrase: Watch This! **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) -------------------------------1199136169 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 12/31/2007 1:39:57 P.M. Central Standard Time,=20 randylsnarr@yahoo.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I am=20 looking for feedback from those who pull fuel directly from their wings th= at=20 do not have slosh boxes installed. My fuel pickups are in the typical plac= e=20 (BL 50 about 2/3 of the way back between the front and rear spar).
I am= =20 contemplating changing the fuel system with a 3 way valve to pull from Lef= t=20 Main and Right tanks.
I would be very interested to know if you ever un= port=20 the fuel and under which conditions it happens if=20 ever.
Randy,
 
I can only answer your question theoretically.  I believe in the=20 simple system pretty much as designed for the wee Lancairs.  As such, t= he=20 wings can be completely emptied into the header tank while in level fli= ght=20 (down to the last cupful), thus maximizing the available fuel= =20 onboard. 
 
Drawing directly from a wing without a slosh chamber means that at some= =20 lesser fuel level, the wing feeding the engine can unport via a slip, s= kid,=20 uncoordinated flight, high pitch angle (extended climb or descent) or a=20 spin.  The fuel level may be different for each of the conditions liste= d=20 and it is doubtful if any were tested whilst the wings were off the airplane= =20 when it is easy to check at certain pitch angles.  Let's see, how about= a=20 Vx, Vy or missed approach climb out with a standard rate=20 turn (albeit slightly uncoordinated) away from the 1/4 filled=20 wing?  Does this mean the checklists for takeoffs, landings and=20 approaches contains a check off  to switch to the wing with a = ;1/2=20 or better fuel quantity?  So many bad possibilities are extant.
 
Some planes that have 3-way selectors and pumps that are=20 utilized to keep the header full, where the header is used for takeoff=20= and=20 landing or reserve only.  The selector valve is considered a backup in=20= case=20 a pump (or the complete electrical system) should fail.
 
Of course, others (like myself) keep the header tank full (>8 gal) a= t=20 all times (engine sole fuel source) and have pre-made the decision that= =20 should they note a pump failure, the "nearest airport" GPS function is=20 activated.  The safest way to reach your destination is with=20 everything working - even if it takes a day or two longer.  We look at=20= the=20 header as the main fuel tank and the wings merely as aux tanks.
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

Darwinian culling phrase: Watch=20 This!



See AOL's top rated recipes and e= asy ways to stay in shape for winter.
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