Return-Path: Sender: (Marvin Kaye) To: lml Date: Tue, 10 Jun 2003 12:59:53 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d02.mx.aol.com ([205.188.157.34] verified) by logan.com (CommuniGate Pro SMTP 4.1b7) with ESMTP id 2410233 for lml@lancaironline.net; Tue, 10 Jun 2003 12:49:57 -0400 Received: from Sky2high@aol.com by imo-d02.mx.aol.com (mail_out_v36.3.) id q.1e0.ac0058b (3310) for ; Tue, 10 Jun 2003 12:49:46 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <1e0.ac0058b.2c17662a@aol.com> X-Original-Date: Tue, 10 Jun 2003 12:49:46 EDT Subject: LOP FLOP, ROP FOP Query for Guru(s) X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_1e0.ac0058b.2c17662a_boundary" X-Mailer: Unknown sub 191 --part1_1e0.ac0058b.2c17662a_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en OK, here goes ---- While some of us have heard and read the words of George Braly and what=E2= =80=99s=20 his name (AvWeb guy - Oh, I remember John Deakin, with the twin), we are sti= ll=20 confused. Why? Well, let me speak for myself. I find no comfort hearing=20 about high flying sixes, some turbo charged, with caveats like =E2=80=9Cfixe= d ignition=20 timing=E2=80=9D, dyno tested, etc. Most flying Lancairs are equipped with l= ittle 4=20 cylinder engines, many pushed to their limits. No matter, I have no cylinde= r envy,=20 nor even inches (cubic) envy. I just want to operate at best power, or max=20 power (for racing) or even economy power for the strange reason of stretchin= g=20 endurance on a long cross country. My confusion in understanding comes from= =20 the following:=20 =E2=80=9CProp efficiency goes down after 2500 rpm.=E2=80=9D Even though Kla= us runs rings=20 around larger engined planes when he is operating in excess of 3000 rpm? Do= es=20 the efficiency go down, but thrust HP is increased? Am I losing power by=20 operating at 2660 rpm (a felt sweet spot)? What is 75% power for my Lycoming I/O 320 engine equipped with a 70 inch=20 Hartzell constant speed prop? I have made the following adjustments: =20 Different pistons were used to raise the compression ratio from 8.5 to 9:1.=20= =20 How was that done? Did it reduce my cubic inches or somehow increase the=20 stroke? A non-filtered induction ram air system is used which raises the manifold=20 pressure 1.5=E2=80=9D Hg at 180 KIAS (195 KTAS). What affect is this on pow= er charts or=20 do I just artificially add1500 feet to the chart scale? The added LASAR ignition system has 2 effects: A hotter spark, burning more fuel in the cylinder. The consequences are a=20 15-20 degree rise in cylinder head temps and a 90-degree reduction in EGTs.=20= =20 This seems to lead to increased torque, thus increased thrust HP because the= =20 prop pitch is increased to retain the RPM. This is seen as a sprightlier=20 take-off run, a higher climb rate and better general performance. What is t= he affect=20 on determining % power? ii. At some RPM/MAP point, the =E2=80=9Cspark=E2=80=9D is advanced, re= sulting in=20 higher power and more efficiency. How does this affect % power at full powe= r and=20 best power? What is the affect when running LOP? The addition of a harmonic dampener, which for fixed pitch props generally,=20 increases the full power rpm by 100. Does this improve my power also by=20 increasing the flywheel affect (allowing an increase in prop pitch to retain= rpm)? Another words, what are the gross parameters I can use to operate LOP? Wha= t=20 are the steps I can use when operating ROP and how many degrees (EGT) rich a= t=20 certain power levels. With the above listed modifications that appear to affect power, should I=20 increase the takeoff fuel flow to something greater than its current 15.1 gp= h? Someone help us little guys with answers to our questions! How else can we= =20 achieve harmony with the universe? Huh? Huh?=20 Grayhawk, AKA Scott Krueger Sky2high@aol.com LNC2 N92EX IO320 Aurora, IL (KARR) PS Formulae accepted. --part1_1e0.ac0058b.2c17662a_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en

OK, here goes ----

 While some of us have heard and read the words of= George Braly and what=E2=80=99s his name (AvWeb guy - Oh, I remember J= ohn Deakin, with the twin), we are still confused.  Why?  We= ll, let me speak for myself.  = I find no comfort hearing about high flying sixes, some turbo charged, with=20= caveats like =E2=80=9Cfixed ignition timing=E2=80=9D, dyno tested, etc.  Most flying Lancairs are equipped= with little 4 cylinder engines, many pushed to their limits.  No matter, I have no cylinder envy, nor eve= n inches (cubic) envy.  I just= want to operate at best power, or max power (for racing) or even economy po= wer for the strange reason of stretching endurance on a long cross country.<= SPAN style=3D"mso-spacerun: yes">  My confusion in understanding= comes from the following: 

  1. =E2=80=9CProp efficiency goes down after 2500 rpm.=E2=80=9D  Even though Klaus runs rings around lar= ger engined planes when he is operating in excess of 3000 rpm?  Does the efficiency go down, but thrust= HP is increased?  Am I losing= power by operating at 2660 rpm (a felt sweet spot)?
  2. What is 75% power for my Lycoming I/O 320 engine equipped with a 70 inch=20= Hartzell constant speed prop?  I have made the following adjustments:

 

    1. Different pistons were used to raise the compression ratio from 8.5 to 9= :1.  How was that done?  Did it reduce my cubic inches or so= mehow increase the stroke?
    2. A non-filtered induction ram air system is used which raises the manifol= d pressure 1.5=E2=80=9D Hg at 180 KIAS (195 KTAS).  What affect is this on power charts or do I just artif= icially add1500 feet to the chart scale?
    3. The added LASAR ignition system has 2 effects:
  1.  A hotter spark, burning mo= re fuel in the cylinder.  The=20= consequences are a 15-20 degree rise in cylinder head temps and a 90-degree=20= reduction in EGTs.  This seems= to lead to increased torque, thus increased thrust HP because the prop pitc= h is increased to retain the RPM.  This is seen as a sprightlier take-off run, a higher climb rate and bet= ter general performance.  What= is the affect on determining % power?

ii.       At some RPM/MAP= point, the =E2=80=9Cspark=E2=80=9D is advanced, resulting in higher power a= nd more efficiency.  How does=20= this affect % power at full power and best power?  What is the affect when running LOP?

    1. The addition of a harmonic dampener, which for fixed pitch props general= ly, increases the full power rpm by 100.&n= bsp; Does this improve my power also by increasing the flywheel affec= t (allowing an increase in prop pitch to retain rpm)?

 Another words, what are the gross parameters I ca= n use to operate LOP?  What ar= e the steps I can use when operating ROP and how many degrees (EGT) rich at=20= certain power levels.

 With the above listed modifications that appear t= o affect power, should I increase the takeoff fuel flow to something greater= than its current 15.1 gph?

 Someone help us little guys with answers to our q= uestions!  How else can we ach= ieve harmony with the universe? Huh? Huh? 

Grayhawk, AKA Scott Krueger
Sky2high@aol.com
LNC2 N92EX IO320 Auror= a, IL (KARR)

PS Formulae accepted.

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