X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sat, 23 Sep 2006 22:01:07 -0400 Message-ID: X-Original-Return-Path: Received: from web61323.mail.yahoo.com ([209.73.179.77] verified) by logan.com (CommuniGate Pro SMTP 5.1c.4) with SMTP id 1416857 for lml@lancaironline.net; Sat, 23 Sep 2006 11:24:45 -0400 Received-SPF: none receiver=logan.com; client-ip=209.73.179.77; envelope-from=charliekohler@yahoo.com Received: (qmail 3910 invoked by uid 60001); 23 Sep 2006 15:24:05 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=W5TmdWNI28oVIjNqJF6OLT5nBzMobVbc78/Up4xhXoLwKAma6ZxQTlRPve8BuKP+eXq8Ae2sIOCNQBeq9BsnGbOyWi2QnAHgAKycQtrFWjXDNy4w8Add3GlyniZ0Y5XOwrENk34ybWy0YYNXK3ikswOAiygBPfGVgV+DAwS3k4g= ; X-Original-Message-ID: <20060923152405.3908.qmail@web61323.mail.yahoo.com> Received: from [68.202.95.219] by web61323.mail.yahoo.com via HTTP; Sat, 23 Sep 2006 08:24:05 PDT X-Original-Date: Sat, 23 Sep 2006 08:24:05 -0700 (PDT) From: Charlie Kohler Reply-To: Charlie Kohler Subject: Re: [LML] Re: Boost pump switching X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-586534779-1159025045=:590" --0-586534779-1159025045=:590 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Perhaps I can shed a light on this subject. The fuel system is principally = a balance between orifice size and pressure.=20 The engine-driven fuel pump has aneroid which puts upper deck air pressure = to regulate a needle valve. If pressure / flow adjustments on this needle v= alve are made without a fuel pump on, to add engine-driven fuel pump pressu= re will increase flow. (Hi Side)=20 =20 On the TSIO 550, above 10,000 feet- use of low pump is a relatively small = increase. Principally it is restoring the fuel to the inlet side of the pum= p. But on take off, you probably couldn't tell the difference. Have you ever noticed that you cannot shut the engine down with the mixture= control if low pump is still on? =20 On the TSIO 550, the use of high boost at Max power will increase the fuel = flow 3 to 5 gallons an hour. At some point the mixture will be so rich the = engine may quit. It definitely will be smoking. =20 If you set up your engine fuel system adjustments to meet the design specif= ications, you could do it either pump on or pump off. With the Lancair, Con= tinental is recommending pump off. But you should know that if you alter th= e pump use procedure, you will not be meeting the design specifications. I= f the settings were made in the opposite configuration. Some aircraft manufacturers use low pump for takeoff and landing, but we do= not advocated in the Lancair IV because we make our adjustments with pump = off.=20 If the fuel pressure/flow is too high on takeoff, you can pull mixture unti= l fuel flow is 43gph and the engine will operate normally. Much above that = and it will begin to smoke. This would indicate it's time to do the fuel ad= justments over and lean the high side. Leaner than 41gph and detonation is = a possibility. The engine can be destroyed in less than a minute. Check FF = on every TO. =20 The low side pressure adjustments should be 7 to 9psi with electric pump of= f at 600rpm. Then idle mixture set to 50 rpm rich.=20 In that order. =20 As an aside, Continental likes to call the primer a "cold start option". T= he best prime for these engines is to put fuel into the intake valve area t= hrough the injector nozzles. (i.e. mixture). But in the extremely cold cond= itions, the primer will definitely aid in getting the engine running.=20 Also using the high pump is a excellent aid for hot start by circulating fu= el from the relatively cool fuel tank into the fuel pump and back out the v= apor return line with a mixture and throttle in the cut off position. =20 That will not take care of hot fuel in the lines from the engine-driven fue= l pump to the nozzles. Usually low pump after the engine start will drive a= ir in those lines out. Or the primer works also.=20 =20 Regarding the use of high pump in-flight as an emergency procedure, you can= always use high pump pressure in case you were to shear a engine-driven fu= el pump drive. If it's too rich -pull the mixture back.=20 IMHO this is a great system that has a lot of redundancy.=20 Supplied clean fuel /set up/ and operated properly. It'll get you home. =20 =20 Charlie K.=20 ----- Original Message ---- From: Tom Gourley To: Lancair Mailing List Sent: Saturday, September 23, 2006 9:43:07 AM Subject: [LML] Re: Boost pump switching So if either low or high boost causes the engine to die what do you do if t= he mechanical pump fails in flight? Or is it only a problem if the boost p= ump is running in tandem with the mechanical pump? (I don't fly behind an = IO-550, just curious.) =20 Tom Gourley ----- Original Message -----=20 From: FredE=20 To: Lancair Mailing List=20 Sent: Friday, September 22, 2006 3:12 PM Subject: [LML] Re: Boost pump switching Chat, I fly a norm. aspirated LIV and never use the pump, hi or lo for takeoff or= landing. It loads up the engine and causes it to die - not desirable. Fred Egli LIV N1228E -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of Chatf= ield S. Daniel Sent: Friday, September 22, 2006 1:28 PM To: Lancair Mailing List Subject: [LML] Re: Boost pump switching You guys don=E2=80=99t turn on low boost for takeoff and landing? Chat Daniel Super ES --0-586534779-1159025045=:590 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

Perhaps I can shed a light on this subject. The fuel syst= em is principally a balance between orifice size and pressure.

The engine-driven fuel pump has aneroid which puts upper = deck air pressure to regulate a needle valve. If pressure / flow adjus= tments on this needle valve are made without a fuel pump on, to add engine-= driven fuel pump pressure will increase flow. (Hi Side)

 

On the TSIO 550, above 10,000 feet- use of  low pump= is a relatively small increase. Principally it is restoring the fuel to th= e inlet side of the pump. But on take off, you probably couldn't tell the d= ifference.

Have you ever noticed that you cannot shut the engine dow= n with the mixture control if low pump is still on?

 

On the TSIO 550, the use of high boost at Max power will = increase the fuel flow 3 to 5 gallons an hour. At some point the mixture wi= ll be so rich the engine may quit. It definitely will be smoking.

 

If you set up your engine fuel system adjustments to meet= the design specifications, you could do it either pump on or pump off= . With the Lancair, Continental is recommending pump off. But you should kn= ow that if you alter the pump use procedure, you will not be meeting the de= sign specifications.  If the settings were made in the opposite config= uration.

Some aircraft manufacturers use low pump for takeoff and = landing, but we do not advocated in the Lancair IV because we make our adju= stments with pump off.

If the fuel pressure/flow is too high on takeoff, you can= pull mixture until fuel flow is 43gph and the engine will operate normally= . Much above that and it will begin to smoke. This wo= uld indicate it's time to do the fuel adjustments over and lean the high si= de. Leaner than 41gph and detonation is a possibility. The engine can be de= stroyed in less than a minute. Check FF on every TO.

 

The low side pressure adjustments should be 7 to 9psi wit= h electric pump off at 600rpm.

Then idle mixture set to 50 rpm rich. 

In that order.

 

 As an aside, Continental likes to call the primer a= "cold start option". The best prime for these engines is to put fuel into = the intake valve area through the injector nozzles. (i.e. mixture). But in = the extremely cold conditions, the primer will definitely aid in getting th= e engine running.

Also using the high pump is a excellent aid for hot start= by circulating fuel from the relatively cool fuel tank into the fuel pump = and back out the vapor return line with a mixture and throttle in the cut o= ff position. 

That will not take care of hot fuel in the lines from the= engine-driven fuel pump to the nozzles. Usually low = pump after the engine start will drive air in those lines out. = Or the primer works also. =

 

Regarding the use of high pump in-flight as an emergency = procedure, you can always use high pump pressure in case you were to shear = a engine-driven fuel pump drive. If it's too rich -pull the mixture back. <= /FONT>

IMHO this is a great system that has a lot of redundancy.=

Supplied clean fuel /set up/ and operated properly.

 It'll get you home.

 


 
Charlie K.=20


----- Original Message ----
From: Tom Gourley <tom.gourley@= verizon.net>
To: Lancair Mailing List <lml@lancaironline.net>Sent: Saturday, September 23, 2006 9:43:07 AM
Subject: [LML] Re: Boost= pump switching

So if either low or high boost causes the = engine to die what do you do if the mechanical pump fails in flight?  = Or is it only a problem if the boost pump is running in tandem with the mec= hanical pump?  (I don't fly behind an IO-550, just curious.)
 
Tom Gourley
----- Original Message -----
From: FredE
Sent: Friday, September 22, 2006 3:1= 2 PM
Subject: [LML] Re: Boost pump switch= ing

Chat,
I fly a norm. aspirated LIV and never use the pump, hi or lo for tak= eoff or landing. It loads up the engine and causes it to die - not desirabl= e.
Fred Egli LIV N1228E
-----Original Message-----
From: Lancair Mailing List = [mailto:lml@lancaironline.net]On Behalf Of Chatfield S. Daniel
Sent: Friday, September 22, 2006 1:28 PM
To: Lancair Mailing= List
Subject: [LML] Re: Boost pump switching

You guys don=E2=80=99= t turn on low boost for takeoff and landing?

Chat Daniel

Super ES

 <= /P>


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