X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp804.mail.sc5.yahoo.com ([66.163.168.183] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with SMTP id 932164 for flyrotary@lancaironline.net; Wed, 04 May 2005 09:52:33 -0400 Received-SPF: none receiver=logan.com; client-ip=66.163.168.183; envelope-from=dcarter@datarecall.net Received: from unknown (HELO Davidscmptr) (dcarter11@sbcglobal.net@66.138.56.210 with login) by smtp804.mail.sc5.yahoo.com with SMTP; 4 May 2005 13:51:46 -0000 Message-ID: <060201c550b0$655eb960$6401a8c0@ip.net> Reply-To: "David Carter" From: "David Carter" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EGT temps Date: Wed, 4 May 2005 08:51:38 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_05FF_01C55086.7BD00FC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 This is a multi-part message in MIME format. ------=_NextPart_000_05FF_01C55086.7BD00FC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable There seem to be recurring questions about EGT - Is it too high? Given the fact that EGT for a particualr engine/exhaust will vary = slightly from other identical engines as a function of "where the EGT = sensor is placed ", and stating at the start that we are talking about = "cruise" power settings - not "full throttle at sea level" (in other = words, we are, by definition only talking about leaning at a lower power = setting, with proper timing and proper octane, where there is ZERO = possibility of detonation) isn't it true that if one adjusts mixture = from rich to lean, that the EGT will "peak" at "best fuel-air ratio" for = complete combustion, and that max power will be achieved by richening a = bit from that (richen until you get max RPM for that immediate flight = condition) which will result in a slight drop in EGT? Then, if one = leans back to "peak" and then continues to lean, one will get "better = economy", and, again, EGT will decrease from what it was at "peak". From reading of what others have said, one can lean past "peak" maybe = 50 degrees and have a safe, economical cruise setting, maybe taking a = slight increase in throttel or manifold pressure to keep HP up to what = you want to cruise at. - The old Air Force BIG radial engines used to cruise at 80 degrees = lean of peak for long flights requiring max economy. A point I like to think of is that 50 or 80 degrees "from" "peak" on the = rich side and on the lean side is, the same temperature. For piston = engines, running 50 deg lean of peak is the same temp as running 50 deg = rich of peak, so the valves are seeing the same temp - so why are some = engine "gurus" so adament about cruising 50 deg rich of peak? It makes = no sense to me. So, I believe there is no such thing as "EGT too high". There is only = "peak EGT", whatever it is for your installation. David=20 ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Tuesday, May 03, 2005 8:55 PM Subject: [FlyRotary] Re: EGT temps Paul, My EGT temps normally range from 1450 (lean) to 1600 and have gone as = high as 1750F, so no, I don't think yours are too high. However, part = of the equation is where are your EGTs located - close the ports, far = from the ports? Mine are approx 8" from the ports. Mold for enlarge duct opening nearly completed today, fiberglass (ugh = {:>)) tomorrow. Then an air filter/plenum to build and I should be = ready in plenty of time for the Mid-Atlantic Fly in 12 May. Ed A ----- Original Message -----=20 From: sqpilot@bellsouth.net=20 To: Rotary motors in aircraft=20 Sent: Wednesday, May 04, 2005 1:37 PM Subject: [FlyRotary] EGT temps Hi all...I flew the SQ2000 again. Engine ran great. Just flew around = enjoying the thing. After removing the thermostat, I found that upon = reaching the end of the runway my water temps were only 120 degrees = instead of the normal 160 to 170 degrees. Temps rose much slower than = normal on climb-out. Actually fun to fly when you don't have to keep = focusing on temps all the time. Cruising at 4500 rpm's, the temps were = very cool....stabilized at around 180 degrees at 1500' AGL. Temos on the = ground were around 78. When I increased the throttle to 5300 rpm's in = level flight, temps slowly started rising. I then noted the EGT at 5300 = rpm's. It was 1425. Does this sound a little too high? If so, my = mixture settings may be a little lean at those rpm's. Just wondering = what others are seeing for EFT temps for around 5300 rpm's. Thanks in = advance for any and all replies. Paul Conner ------=_NextPart_000_05FF_01C55086.7BD00FC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
There seem to be recurring questions = about EGT - Is=20 it too high?
 
Given the fact that EGT for a = particualr=20 engine/exhaust will vary slightly from other identical engines = as a=20 function of  "where the EGT sensor is placed ", and stating at the = start=20 that we are talking about "cruise" power settings - not "full throttle = at sea=20 level" (in other words, we are, by definition only talking about leaning = at a=20 lower power setting, with proper timing and proper octane, where there = is ZERO=20 possibility of detonation) isn't it true that if one adjusts mixture = from rich=20 to lean, that the EGT will "peak" at "best fuel-air ratio" for complete=20 combustion, and that max power will be achieved by richening a bit from = that=20 (richen until you get max RPM for that immediate flight condition) which = will=20 result in a slight drop in EGT?  Then, if one leans back to "peak" = and then=20 continues to lean, one will get "better economy", and, again, EGT will = decrease=20 from what it was at "peak".
 
  From reading of what others have = said, one=20 can lean past "peak" maybe 50 degrees and have a safe, economical cruise = setting, maybe taking a slight increase in throttel or manifold pressure = to keep=20 HP up to what you want to cruise at.
    -  The old Air = Force BIG=20 radial engines used to cruise at 80 degrees lean of peak for long = flights=20 requiring max economy.
 
A point I like to think of is that 50 = or 80 degrees=20 "from" "peak" on the rich side and on the lean side is, the same=20 temperature.  For piston engines, running 50 deg lean of peak is = the same=20 temp as running 50 deg rich of peak, so the valves are seeing the same = temp - so=20 why are some engine "gurus" so adament about cruising 50 deg = rich of=20 peak?  It makes no sense to me.
 
So, I believe there is no such thing as = "EGT too=20 high".  There is only "peak EGT", whatever it is for  your=20 installation.
 
David 
----- Original Message -----=20
From: Ed=20 Anderson
Sent: Tuesday, May 03, 2005 8:55 PM
Subject: [FlyRotary] Re: EGT temps

Paul,
 
My EGT temps normally range from 1450 = (lean) to=20 1600 and have gone as high as 1750F, so no, I don't think yours are too=20 high.  However, part of the equation is where are your EGTs located = - close=20 the ports, far from the ports?  Mine are approx 8" from the=20 ports.
 
Mold for enlarge duct opening nearly = completed=20 today, fiberglass (ugh {:>)) tomorrow.  Then an air = filter/plenum to=20 build and I should be ready in plenty of time for the Mid-Atlantic Fly = in 12=20 May.
 
Ed A
----- Original Message -----
From:=20 sqpilot@bellsouth.net
Sent: Wednesday, May 04, 2005 = 1:37=20 PM
Subject: [FlyRotary] EGT = temps

Hi all...I flew the SQ2000 again. = Engine ran=20 great. Just flew around enjoying the thing.  After removing the=20 thermostat, I found that upon reaching the end of the runway my water = temps=20 were only 120 degrees instead of the normal 160 to 170 degrees. Temps = rose=20 much slower than normal on climb-out.  Actually fun to fly when = you don't=20 have to keep focusing on temps all the time.  Cruising at 4500 = rpm's, the=20 temps were very cool....stabilized at around 180 degrees at 1500' AGL. = Temos=20 on the ground were around 78.  When I increased the throttle to = 5300=20 rpm's in level flight, temps slowly started rising. I then noted the = EGT at=20 5300 rpm's. It was 1425.  Does this sound a little too = high?  If so,=20 my mixture settings may be a little lean at those rpm's.  Just = wondering=20 what others are seeing for EFT temps for around 5300 rpm's.  = Thanks in=20 advance for any and all replies.  Paul=20 Conner
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