Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Mon, 03 Jan 2005 12:03:17 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m16.mx.aol.com ([64.12.138.206] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 589929 for lml@lancaironline.net; Mon, 03 Jan 2005 10:40:12 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.206; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m16.mx.aol.com (mail_out_v37_r3.8.) id q.1b8.9c43284 (3924) for ; Mon, 3 Jan 2005 10:39:39 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <1b8.9c43284.2f0ac13b@aol.com> X-Original-Date: Mon, 3 Jan 2005 10:39:39 EST Subject: Re: [LML] Re: airspeed vs. power X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1104766779" X-Mailer: 9.0 Security Edition for Windows sub 5000 -------------------------------1104766779 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 1/3/2005 8:21:15 A.M. Central Standard Time, glcasey@adelphia.net writes: If the air flow into the servo changes its "pattern" the reference pressure could change, upsetting the calibration. In other words, it could be that the air swirls in a particular way under one conditions and then detaches from the wall or otherwise changes its flow pattern at another condition. This is especially true if the air has to make a sharp bend at the servo inlet. So what you are seeing could very well happen - the effect just isn't built into the system. As an example, my Cardinal has a very nicely designed servo inlet and the air/fuel ratio is very constant over a wide range of rpms and throttle openings. Come help me finish my ES and I'll report on that... Gary, Exactly. This is so much fun. It is another example of why each homebuilt Lancair can be the same, yet different from each other one and certainly different from any STC aircraft. I really try to send enough of the environmental conditions so that the data is usable and maybe even comparable to other Lancairs similarly equipped. I certainly agree that the flow pattern can change - In my case primarily from the angle of the entry air and the pressure that all or some of the "venturis" see in the throat of the throttle body because there are no bends in the induction system before the throttle body. It not only is a straight shot, there is no filter to mottle the air, no expansion chamber, and no flow disruption since the walls are smooth (polished fiberglass with a plumber's sleeve interconnect). What I really need is a JPI engine monitor - I can't always record (write down) all the things (cowl pressure, temp, lower cowl pressure, injector air pressure, flight parameters, power settings and cylinder data, and fly the plane thru a transition - not enough sensors, not enough arms and definitely not enough brains. Hmmmm, maybe I need a video camera with a wide angle lens pointed at the panel......... No, I cannot help with your ES as I am using too much gas trying to understand the effect of all the goofy things I have done. I am certainly learning a great deal from so many contributors here on LML. Oh, and one more thing - the reference pressure applied to the injectors does not affect the fuel flow, but it does affect the reading of a pressure-type fuel flow indicator. The indicator is a pressure gage that is referenced to the pressure inside the cabin. The pressure drop in the injector itself is, however, referenced to the vent pressure at the injector. It is a small effect, but could change your fuel flow readings slightly. It is not a small effect. I have demonstrated that altering the airflow that an injector utilizes alters the consequences to fuel passing thru it. Of course, measured indirectly, like the first cylinder to lean and the cruise EGT spread. You know, I may draw the wrong conclusions thru ignorance, but I can't change the data. Things just happen in flight that don't happen on a dyno stand. I do not have a pressure-type fuel flow indicator. I have a sensor that actually measures fuel flow. I have an idiot light (informing the light-idiot behind the yoke) that warns of low fuel pressure (12 psi) - it seems to indicate one of the three requirements for combustion might stop flowing if the pressure (for whatever reason) gets too low. BTW, you ought to see what .001 injector diameter change can do to a cylinder's performance - just ask GAMI. After all, all I am trying to do is get the same max/best power out of each cylinder so I can get to the head of the line. I enjoy stumbling along paths not often taken. Scott Krueger AKA Grayhawk Lancair N92EX IO320 Aurora, IL (KARR) -------------------------------1104766779 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 1/3/2005 8:21:15 A.M. Central Standard Time,=20 glcasey@adelphia.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>If
the air flow into the servo changes its "pattern" the refer= ence=20 pressure
could change, upsetting the calibration.  In other words,= it=20 could be that
the air swirls in a particular way under one conditions a= nd=20 then detaches
from the wall or otherwise changes its flow pattern at=20 another condition.
This is especially true if the air has to make a sha= rp=20 bend at the servo
inlet.  So what you are seeing could very well=20 happen - the effect just
isn't built into the system.  As an examp= le,=20 my Cardinal has a very nicely
designed servo inlet and the air/fuel rat= io=20 is very constant over a wide
range of rpms and throttle openings. = =20 Come help me finish my ES and I'll
report on that...
Gary,
 
Exactly.  This is so much fun.  It is another example of why=20= each=20 homebuilt Lancair can be the same, yet different from each other one an= d=20 certainly different from any STC aircraft.   I really try to send=20 enough of the environmental conditions so that the data is usable and maybe=20= even=20 comparable to other Lancairs similarly equipped.  I certainly agree tha= t=20 the flow pattern can change - In my case primarily from the angle of the ent= ry=20 air and the pressure that all or some of the "venturis" see in the thro= at=20 of the throttle body because there are no bends in the induction system= =20 before the throttle body.  It not only is a straight shot, there is no=20 filter to mottle the air, no expansion chamber, and no flow disruption since= the=20 walls are smooth (polished fiberglass with a plumber's sleeve=20 interconnect).  What I really need is a JPI engine monitor - I can't al= ways=20 record (write down) all the things (cowl pressure, temp, lower cowl pressure= ,=20 injector air pressure, flight parameters, power settings and cylinder data,=20= and=20 fly the plane thru a transition - not enough sensors, not enough arms a= nd=20 definitely not enough brains.  Hmmmm, maybe I need a video camera with=20= a=20 wide angle lens pointed at the panel.........
 
No, I cannot help with your ES as I am using too much gas trying t= o=20 understand the effect of all the goofy things I have done.  I am certai= nly=20 learning a great deal from so many contributors here on LML.
 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Oh,=20 and  one more thing - the reference pressure applied to the=20 injectors
does not affect the fuel flow, but it does affect the reading= of=20 a
pressure-type fuel flow indicator.  The indicator is a pressure=20= gage=20 that is
referenced to the pressure inside the cabin.  The pressure= =20 drop in the
injector itself is, however, referenced to the vent pressur= e at=20 the
injector.  It is a small effect, but could change your fuel fl= ow=20 readings
slightly.

 
It is not a small effect.  I have demonstrated that altering the=20 airflow that an injector utilizes alters the consequences to fuel=20 passing thru it. Of course, measured indirectly, like the first cylinde= r to=20 lean and the cruise EGT spread.  You know, I may draw the wrong conclus= ions=20 thru ignorance, but I can't change the data.
 
Things just happen in flight that don't happen on a dyno stand. 
 
 I do not have a pressure-type fuel flow indicator.  I have a= =20 sensor that actually measures fuel flow.  I have an idiot light (inform= ing=20 the light-idiot behind the yoke) that warns of low fuel pressure (12 psi) -=20= it=20 seems to indicate one of the three requirements for combustion mig= ht=20 stop flowing if the pressure (for whatever reason) gets too low.
 
BTW, you ought to see what .001 injector diameter change can do=20 to a cylinder's performance - just ask GAMI.
 
After all, all I am trying to do is get the same max/best power out of=20= each=20 cylinder so I can get to the head of the line.  I enjoy stumbling along= =20 paths not often taken.
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 Aurora, IL (KARR)
 
 


 -------------------------------1104766779--