X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from an-out-0708.google.com ([209.85.132.250] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1907426 for flyrotary@lancaironline.net; Wed, 07 Mar 2007 12:41:55 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.132.250; envelope-from=rotary.thjakits@gmail.com Received: by an-out-0708.google.com with SMTP id c34so184798anc for ; Wed, 07 Mar 2007 09:41:08 -0800 (PST) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=jZ8XjlOCiCjyxK8ox4afCVRtu8/nYSc4Y3UoOEvr3VzKIhdXqPsn9TcTpmWL6pRXp9NpzERs+u7zWSZFvTK7DgP+PIc9YKAXZJTiTJAJJujVTTEM5uhTh4/gd+mNKf+q8pWxKJR81JL6vg5WPRb6oCZvY1bgUITh2apLugUSqYc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=E2B2Nj9C7FcEaKjusQ9x1x3fnJBTqZko0d+hudHXcB4uRRrT6Di9fpwJz9uZjftKSgYhZD0uM7f5CBfDiBVVTn5Kws7/+04xPsBZ/1iilCVarCXSqGD/0Jg8N4+/5AlL3wvZA2Vxw6UTgQuFHb6XDBY4uKg1+y+mYwsJAYJDiYI= Received: by 10.100.111.16 with SMTP id j16mr4746184anc.1173289267946; Wed, 07 Mar 2007 09:41:07 -0800 (PST) Received: by 10.100.195.12 with HTTP; Wed, 7 Mar 2007 09:41:07 -0800 (PST) Message-ID: <63163d560703070941n211d6c2dp26256a0136ee6672@mail.gmail.com> Date: Wed, 7 Mar 2007 12:41:07 -0500 From: "Thomas Jakits" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: fuel filter In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_102551_31476471.1173289267897" References: ------=_Part_102551_31476471.1173289267897 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi all, it seems general wisdom suggests the pumps in the tank and a high-pressure line to the engine. Makes sense from a vapor-lock/fuel starvation POV. Just a little note: I fly a Aerospatiale Alouette III, which has a electric booster and an engine driven main pump. The booster stays on at all times. Also fly a EC120 and a AS350B3: booster on only for start-up or in-flight emergency (Loss of Fuel-P). Normal ops requires the engine-driven pump to lift the fuel up to 1.6m in suction. The idea behind this is safety. You don't want high pressure when something starts to leak!! However it is imperative to use the booster for start-up or you risk to burn the engine-driven pump. My idea was/is too to have a gravity-system into a header-sump in the rear (tractor, BD-4), dual in-tank, high pressure to engine. However I do start to look into a alternative suction system. One way would be to shield the HP lines under the belly, outside the cabin. By the way the EC helicopters (EC120 and AS350B3) have no back-up pumps!! It seems quality and statistics agree on less complex is safer! Thomas On 3/7/07, Lehanover@aol.com wrote: > > In a message dated 3/7/2007 9:51:24 A.M. Eastern Standard Time, > downing.j@sbcglobal.net writes: > > Looking at the pictures of fuel filter, pump installations, the filter is > after the pump. In auto installations the pump in tank has a screened inlet > and then filter someplace between the pump and the injection system. The > plane has a gascolator and do I place the pump next like auto installations, > then into the filter like the auto installations, or why not. JohnD > > > The small in the tank high pressure pumps used in fuel injection are not > tolerant of even small debris. Thus the filter sock on the pickup. once > through the pump there is only the very small micron filter in the injector. > So a filter after the pump is a must, and it needs a slightly smaller micron > rating than the screen in the injector. > > Gascolators generally have course screens in the top, and are of no value > in protecting injected systems. OK for carburetted systems. > > The pumps should be mounted in the tanks or close to and below the tanks > where possible. > > Pushing fuel under pressure is preferred to trying to suck it uphill from > a tank. On a hot day, > and, or, with a length of fuel line close to a heat source, you will boil > the fuel in the line, followed by a quiet period of glider practice. > > Notice that modern cars are nearly immune to vapor lock (boiling fuel). > Because the pump is in the bottom of the cool fuel in the tank, pushing the > fuel. > > Auto fuel boils more readily than aircraft fuel. So the shortest suction > side run possible is best. Also, for any particular heat load, higher > altitude means less pressure on the fuel surface in the tank, and boiling > may occur. > > > The race car uses a disposable filter from the parts store (inline can > with push on ends) for about $2.00 each. These on the suction side of two > sliding vane pumps mounted even with the fuel cell bottom. All of the > pressurized fuel goes through a 16 micron filter then to the pressure > regulator and the carb. The regulator is right beside the carb, so the > highest pressure fuel is maintained to as close to the carb as is possible. > > Carbs and sliding vane pumps are tolerant of larger debris than are roller > style high pressure pumps. > > > Lynn E. Hanover > > > > ------------------------------ > AOL now offers free email to everyone. Find out more about what's free > from AOL at *AOL.com*. > > ------=_Part_102551_31476471.1173289267897 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi all,

it seems general wisdom suggests the pumps in the tank and a high-pressure line to the engine.
Makes sense from a vapor-lock/fuel starvation POV.
Just a little note:

I fly a Aerospatiale Alouette III, which has a electric booster and an engine driven main pump.
The booster stays on at all times.
Also fly a EC120 and a AS350B3: booster on only for start-up or in-flight emergency (Loss of  Fuel-P).
Normal ops requires the engine-driven pump to lift the fuel up to 1.6m in suction.
The idea behind this is safety. You don't want high pressure when something starts to leak!!
However it is imperative to use the booster for start-up or you risk to burn the engine-driven pump.

My idea was/is too to have a gravity-system into a header-sump in the rear (tractor, BD-4), dual in-tank, high pressure to engine.
However I do start to look into a alternative suction system.
One way would be to shield the HP lines under the belly, outside the cabin.

By the way the EC helicopters (EC120 and AS350B3) have no back-up pumps!!
It seems quality and statistics agree on less complex is safer!

Thomas


On 3/7/07, Lehanover@aol.com <Lehanover@aol.com> wrote:
In a message dated 3/7/2007 9:51:24 A.M. Eastern Standard Time, downing.j@sbcglobal.net writes:
Looking at the pictures of fuel filter, pump installations, the filter is after the pump.  In auto installations the pump in tank has a screened inlet and then filter someplace between the pump and the injection system.  The plane has a gascolator and do I place the pump next like auto installations, then into the filter like the auto installations, or why not.  JohnD
 
The small in the tank high pressure pumps used in fuel injection are not tolerant
of even small debris. Thus the filter sock on the pickup. once through the pump there is only the very small micron filter in the injector. So a filter after the pump is a must, and it needs a slightly smaller micron rating than the screen in the injector.
 
Gascolators generally have course screens in the top, and are of no value in protecting injected systems. OK for carburetted systems.
 
The pumps should be mounted in the tanks or close to and below the tanks where possible.
 
Pushing fuel under pressure is preferred to trying to suck it uphill from a tank. On a hot day,
and, or, with a length of fuel line close to a heat source, you will boil the fuel in the line, followed by a quiet period of glider practice.
 
Notice that modern cars are nearly immune to vapor lock (boiling fuel). Because the pump is in the bottom of the cool fuel in the tank, pushing the fuel.
 
Auto fuel boils more readily than aircraft fuel. So the shortest suction side run possible is best. Also, for any particular heat load, higher altitude means less pressure on the fuel surface in the tank, and boiling may occur. 
 
 
The race car uses a disposable filter from the parts store (inline can with push on ends) for about $2.00 each. These on the suction side of two sliding vane pumps mounted even with the fuel cell bottom. All of the pressurized fuel goes through a 16 micron filter then to the pressure regulator and the carb. The regulator is right beside the carb, so the highest pressure fuel is maintained to as close to the carb as is possible.
 
Carbs and sliding vane pumps are tolerant of larger debris than are roller style high pressure pumps. 
 
 
Lynn E. Hanover



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