X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 28 Sep 2007 15:31:02 -0400 Message-ID: X-Original-Return-Path: Received: from web62503.mail.re1.yahoo.com ([69.147.75.95] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with SMTP id 2357199 for lml@lancaironline.net; Fri, 28 Sep 2007 09:23:18 -0400 Received-SPF: none receiver=logan.com; client-ip=69.147.75.95; envelope-from=charliekohler@yahoo.com Received: (qmail 29801 invoked by uid 60001); 28 Sep 2007 13:22:41 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type:Message-ID; b=B6BPFMAwUe4dqua7KoGCMHhN+Z4F1qy5db5uawGI9g6xM7jJJUwq5BiI9iDhNiT7BeM0u6U3s32T8uDh4rUVOVRbnUJCfLDwXN/HCcWrbG8KJHGzZHI/oyZJoNjOQJOKMyi62SdAZzbjskzXX9AQVuvgctenRDBcKm6vfDLfVz0=; X-YMail-OSG: 0zh82.UVM1ksG1BBmiHkTfD.dp4zEOTOggiUGGG1Cp626USuU1cbgfioYlJ9aX_4XVPxzDVOhZUCRAQ1y8Lq73xSC1W9PBitDAU07Wu4ArHL4BIspUxVpr7BEO9.Uw-- Received: from [69.147.75.148] by web62503.mail.re1.yahoo.com via HTTP; Fri, 28 Sep 2007 06:22:41 PDT X-Mailer: YahooMailRC/651.50 YahooMailWebService/0.7.134 X-Original-Date: Fri, 28 Sep 2007 06:22:41 -0700 (PDT) From: Charlie Kohler Subject: Re: [LML] fuel tank drains X-Original-To: Lancair Mailing List MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-72517795-1190985761=:29446" X-Original-Message-ID: <450950.29446.qm@web62503.mail.re1.yahoo.com> --0-72517795-1190985761=:29446 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable You might comment on installing additional inline automotive (non-bypass) v= ery fine filters upstream of gascolator. =0A =0A =0ACharlie K.=0A=0A=0A=0A-= ---- Original Message ----=0AFrom: Bill Hannahan =0AT= o: lml@lancaironline.net=0ASent: Friday, September 28, 2007 8:36:04 AM=0ASu= bject: [LML] fuel tank drains=0A=0A=0A =0AI was asked to come up with a tec= hnical note for our EAA news letter and I want to bounce it off you guys. T= hanks in advance for your review comments.=0A =0A =0A =0ASometimes when I v= isit a project the builder will show me how he has installed the fuel picku= p in the lowest point of the tank and proudly declares =93All my fuel is us= able.=94=0A =0AThen I say, =93Suppose you get some water in your fuel, wher= e does that go?=94 That is generally followed by a long uneasy silence.=0A = =0AComposite wing skins frequently have about a half inch of lightweight co= re material to create a stiff wing skin. Integral wing fuel tanks usually h= ave a drain that is mounted in the bottom skin penetrating this core materi= al. There may be additional plies of reinforcement around the penetration. = In some cases the drains are recessed into the skin to be flush. The actual= opening where the drain fuel is withdrawn may be as much as =BE inch above= the lower wing surface.=0A =0AMeanwhile the builder has installed the fuel= pickup right next to the inboard rib at the lowest point of the tank where= there is no core material.=0A =0AThis is a case where a pilot could drain = a large sample of clean gas while the fuel pickup is under water.=0A =0AIma= gine a large coffee can sitting vertically on your work bench. Drill a hole= in the side of the can two inches above the bottom and install a fuel tank= drain valve in that hole. Now drill another hole four inches above the bot= tom and install a finger strainer.=0A =0AHere you have a fuel tank. The fue= l above the finger strainer is usable fuel, and the fuel below the finger s= trainer is unusable fuel. We learned all about those two things when we bec= ame pilots.=0A =0ABut the unusable fuel can be divided into two sub volumes= . The fuel below the strainer and above the drain is =93drainable unusable = fuel=94, and the fuel below the drain is =93undrainable unusable=94 fuel. = =0A =0AThe undrainable unusable volume is of no value to us. It will probab= ly fill with water, which is dead weight we will have to carry with us all = the time. It may eventually grow some microbes that will generate waste pro= ducts that could clog our fine screens.=0A =0AThe drainable unusable space = provides a place for water from condensation or contamination to accumulate= without being sucked into the engine, and that water can be drained before= flight.=0A =0AHow big should the drainable unusable space be? That=92s up = to you, the manufacturer, it is a tradeoff between lost range and water cap= acity. =0A =0AFAR part 23 says;=0A =0ASec. 23.971 Fuel tank sump.=0A(a) Eac= h fuel tank must have a drainable sump with an effective capacity, in the n= ormal ground and flight attitudes, of 0.25 percent of the tank capacity, or= 1/16 gallon, whichever is greater.=0A(b) Each fuel tank must allow drainag= e of any hazardous quantity of water from any part of the tank to its sump = with the airplane in the normal ground attitude.=0A(c) Each reciprocating e= ngine fuel system must have a sediment bowl or chamber that is accessible f= or drainage; has a capacity of 1 ounce for every 20 gallons of fuel tank ca= pacity; and each fuel tank outlet is located so that, in the normal flight = attitude, water will drain from all parts of the tank except the sump to th= e sediment bowl or chamber. =0A =0A[This is confusing, I think water should= drain from all parts of the tank to the sump. Perhaps they mean any water = that gets into the outlet line should drain to the sediment bowl] =0A =0A = =0A0.25% feels a bit low, something close to 1% of tank volume sounds reas= onable. So, for a 20 gallon tank that would be 0.2 gallons of drainable un= usable fuel.=0A =0ATanks that use bladders may hold a great deal of water i= n wrinkles on the bottom surface. A much more conservative approach may be = needed.=0A =0A =0A=0A=0A=0ARegards,=0ABill Hannahan=0A=0Awfhannahan@yahoo.c= om=0A=0A=0ABuilding a website is a piece of cake. =0AYahoo! Small Business = gives you all the tools to get online. --0-72517795-1190985761=:29446 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
=0A
You might comment on installing addition= al inline automotive (non-bypass) very fine filters upstream of gascol= ator.
=0A
 
 
Charlie K.=0A


= =0A
----- Original Message ----
From: Bill Hannahan <wfhanna= han@yahoo.com>
To: lml@lancaironline.net
Sent: Friday, September 2= 8, 2007 8:36:04 AM
Subject: [LML] fuel tank drains

=0A
 =
=0A
=0A
I was asked to come up with a= technical note for our EAA news letter and I want to bounce it off you guy= s. Thanks in advance for your review comments.
=0A
 
=0A
 
=0A
 
=0A
Sometimes when I visit a project = the builder will show me how he has installed the fuel pickup in the lowest= point of the tank and proudly declares =93All my fuel is usable.=94
= =0A
 
=0A
Then I say,= =93Suppose you get some water in your fuel, where does that go?=94 That is= generally followed by a long uneasy silence.
=0A
 
=0A
Composite wing skins frequently hav= e about a half inch of lightweight core material to create a stiff wing ski= n. Integral wing fuel tanks usually have a drain that is mounted in the bot= tom skin penetrating this core material. There may be additional plies of r= einforcement around the penetration. In some cases the drains are recessed = into the skin to be flush. The actual opening where the drain fuel is withd= rawn may be as much as =BE inch above the lower wing surface.
=0A
 
=0A
Meanwhile the build= er has installed the fuel pickup right next to the inboard rib at the lowes= t point of the tank where there is no core material.
=0A
 
=0A
This is a case where a pilot= could drain a large sample of clean gas while the fuel pickup is under wat= er.
=0A
 
=0A
Im= agine a large coffee can sitting vertically on your work bench. Drill a hol= e in the side of the can two inches above the bottom and install a fuel tan= k drain valve in that hole. Now drill another hole four inches above the bo= ttom and install a finger strainer.
=0A
 =0A
Here you have a fuel tank. The fuel above the= finger strainer is usable fuel, and the fuel below the finger strainer is = unusable fuel. We learned all about those two things when we became pilots.=
=0A
 
=0A
But t= he unusable fuel can be divided into two sub volumes. The fuel below the st= rainer and above the drain is =93drainable unusable fuel=94, and the fuel b= elow the drain is =93undrainable unusable=94 fuel.
=0A
 
=0A
The undrainable unusable volu= me is of no value to us. It will probably fill with water, which is dead we= ight we will have to carry with us all the time. It may eventually grow som= e microbes that will generate waste products that could clog our fine scree= ns.
=0A
 
=0A
Th= e drainable unusable space provides a place for water from condensation or = contamination to accumulate without being sucked into the engine, and that = water can be drained before flight.
=0A
 =0A
How big should the drainable unusable space b= e? That=92s up to you, the manufacturer, it is a tradeoff between lost rang= e and water capacity.
=0A
 
=0A
FAR part 23 says;
=0A
 =0A
Sec. 23.971 Fuel tank sump.=
=0A
(a) Each fuel tank must have a drainable sump with= an effective capacity, in the normal ground and flight attitudes, of 0.25 = percent of the tank capacity, or 1/16 gallon, whichever is greater.
= =0A
(b) Each fuel tank must allow drainage of any hazardous quantity of= water from any part of the tank to its sump with the airplane in the norma= l ground attitude.
=0A
(c) Each reciprocating en= gine fuel system must have a sediment bowl or chamber that is accessible fo= r drainage; has a capacity of 1 ounce for every 20 gallons of fuel tank cap= acity; and each fuel tank outlet is located so that, in the normal flight a= ttitude, water will drain from all parts of the tank except the sump to the= sediment bowl or chamber.
=0A
 
=0A<= DIV class=3DMsoNormal>[This is confusing, I think water should drain from a= ll parts of the tank to the sump. Perhaps they mean any water that gets int= o the outlet line  should drain to the sediment bowl] =0A
 
=0A
 =0A
0.25% feels a bit low, something close to 1% =  of tank volume sounds reasonable. So, for a 20 gallon ta= nk that would be 0.2  gallons of drainable unusable fuel.=
=0A
 
=0A
Tanks= that use bladders may hold a great deal of water in wrinkles on the bottom= surface. A much more conservative approach may be needed.
=0A
 
=0A
 


= =0A
Regards,
=0A
Bill Hannahan
=0A=0A

=0A

=0ABuilding a website is a piece of cake.=
Yahoo! Small Business gives you all the tools to get online.

=
--0-72517795-1190985761=:29446--