X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmfepo201.cox.net ([68.230.241.146] verified) by logan.com (CommuniGate Pro SMTP 5.4c2a) with ESMTP id 4840143 for flyrotary@lancaironline.net; Sun, 06 Feb 2011 15:15:39 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.146; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmfepo201.cox.net (InterMail vM.8.01.04.00 201-2260-137-20101110) with ESMTP id <20110206201503.TWRD16474.fed1rmfepo201.cox.net@fed1rmimpo03.cox.net> for ; Sun, 6 Feb 2011 15:15:03 -0500 Received: from BigAl ([72.199.216.14]) by fed1rmimpo03.cox.net with bizsmtp id 4kF31g0080KDB3c04kF35j; Sun, 06 Feb 2011 15:15:03 -0500 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=icgemsq+LqMGY4m7IOkEF2G2WQn18U66bW9J96xD/bo= c=1 sm=1 a=oPhr9CcUDrIA:10 a=TPvrVRyicAsl4VeEYn0L5g==:17 a=Ia-xEzejAAAA:8 a=3oc9M9_CAAAA:8 a=HZJGGiqLAAAA:8 a=Ht2q7I9mPl9T22L2XKEA:9 a=8_9D9wfh1vT1wttAuhIA:7 a=c8QuzFQBqBcwDhUJVrbjBbZ6xmgA:4 a=CjuIK1q_8ugA:10 a=EzXvWhQp4_cA:10 a=U8Ie8EnqySEA:10 a=HeoGohOdMD0A:10 a=dxHwI7qPngC1Joul:21 a=xjia8_EZRGNYZJ2v:21 a=Q9zdRHX2uK2e1UtfS0YA:9 a=0gwX505r2BDtFnkMuAoA:7 a=gOiMcCep9JqMa2CX2BkuH81eacMA:4 a=TPvrVRyicAsl4VeEYn0L5g==:117 X-CM-Score: 0.00 Authentication-Results: cox.net; none From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: EGT Values and recovery. Date: Sun, 6 Feb 2011 12:17:19 -0800 Message-ID: <5446CEE293944EC89FC0E31356A44E26@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01CBC5F7.CCBE5210" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6863 Importance: Normal Thread-Index: AcvGNLeJG54dNmm7Q3a8uvYxAG94tAABCDwg In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5994 This is a multi-part message in MIME format. ------=_NextPart_000_0000_01CBC5F7.CCBE5210 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I think this discussion is causing some confusion. I understand and = agree with the idea of avoiding peak EGT; however, how you operate depends on engine controller, and maybe to some extend on racing vs flying. (Maybe Lynn's remarks were specific to Mistral's EC) With Tracy EC, once you get the engine 'tuned' (mixture vs MAP); and you = set the knob to be rice of peak; it's ROP no mater what the throttle = setting. You can choose your knob setting to give you something like 1600-1650 = EGT on climb out; pull your throttle back to cruise (or lower power to limit = oil temp if that's your issue) and not have an EGT issue. =20 =20 When you're in stable cruise then turn the knob to your LOP lean cruise condition. You'll want to lean to a point where your EGT is again at = 1600 (or lower if it is still running reasonably smooth). You just don't want = to do your climb-out, or your cruise at peak EGT. =20 At least that's my story, =20 Al =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com Sent: Sunday, February 06, 2011 11:33 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EGT Values and recovery. =20 In a message dated 2/6/2011 10:27:50 A.M. Eastern Standard Time, keltro@att.net writes: Lynn, Do I understand this correctly.................You are saying that = for maximum efficiency that we need to fly with full throttle at both climb and cruise and control "EGT" with = mixture control (and /or ECU map settings) .............Slightly richer than best power for climb (to reduce EGT to less than 1650 F) then lean quickly=20 (to lean stumble) then slightly richer.............The bottom line that being that trying to control "EGT" with the=20 throttle will not help efficiency since it increases pumping losses and = only slightly reduces "EGT".............. =20 Kelly Troyer "DYKE DELTA JD2" (Eventually) "13B ROTARY"_ Engine Pulling off throttle is a good way to reduce total engine heat as in = when you have an oil cooling problem and EGTs.=20 =20 From a climb setting at 1600 on the EGT you are fuel cooling the engine = to good extent. This is a costly way to cool any engine. But no damage will occur, and power will be good. So instead of fuel cooling......... the over-lean mixture cools by removing BTUs. Smaller fire. Less heat. Better more thorough burn due to excess oxygen. Lower oil temps. And = so-on.=20 =20 The rotor face is close to or in front of the spark plugs longer than a piston engine. More dwell. So less advance is needed, and there is more = time for the over-lean mixture to burn. Thus more efficient than a piston = engine? Not quite but very close. Add a monster ignition system and lean even further. =20 That 1600 degrees is several hundred degrees from best power. That = leaning to lean of peak EGT must be done very quickly. As you turn the leaning = knob or pull on the cable, you will pass right through the very point we are trying to avoid, best power and peak EGT. Or, pull of just a bit of throttle, then go lean and put the throttle back up. One must not diddle = at or near peak EGT. Or, tune "B" for lean of peak and just flip the = switch.=20 =20 This is not some new idea. If your piston engine has enough compression = to run lean of peak, it should be run so in cruise all of the time. All big radials use fuel as fast as you can pour it out of a bucket. Were it not = for lean of peak operation they had very limited range, and poor payloads. =20 In the Fiat we never ran full throttle. I found on the dyno that more = power was available just short of full throttle. My guess was that the = butterflies at slightly less than straight up and down, helped turn the mixture a = bit. An extra 3 HP every time. =20 Airplanes are dynamometers.=20 Take advantage. Make one change at a time. Record everything. Use SAE = tables to correct to sea level HP.=20 =20 Lynn E. Hanover ------=_NextPart_000_0000_01CBC5F7.CCBE5210 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I think this = discussion is causing some confusion.  I understand and agree with the idea of avoiding peak EGT; however, how you operate depends on engine = controller, and maybe to some extend on racing vs flying.  (Maybe Lynn’s = remarks were specific to Mistral’s EC)

With Tracy EC, once you = get the engine ‘tuned’ (mixture vs MAP); and you set the knob to be rice of peak; it’s = ROP no mater what = the throttle setting. You can choose your knob setting to give you something like = 1600-1650 EGT on climb out; pull your throttle back to cruise (or lower power to limit = oil temp if that’s your issue) and not have an EGT issue.  =

 

When you’re in stable = cruise then turn the knob to your LOP lean cruise condition.  You’ll want = to lean to a point where your EGT is again at 1600 (or lower if it is still running reasonably smooth). You just don’t want to do your = climb-out, or your cruise at peak EGT.

 

At least that’s my = story,

 

Al

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com
Sent: Sunday, February = 06, 2011 11:33 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = EGT Values and recovery.

 

In a message dated 2/6/2011 10:27:50 A.M. Eastern Standard Time, = keltro@att.net writes:

Lynn,

  &nbs= p;   Do I understand this correctly.................You are saying that = for maximum efficiency that we need to fly

with full throttle at both climb and cruise and = control "EGT" with mixture control (and /or ECU map settings)

.............Sli= ghtly richer than best power for climb (to reduce EGT to less than 1650 F) = then lean quickly

(to lean stumble) then slightly richer.............The bottom line that = being that trying to control "EGT" with the

throttle will not help efficiency since it increases pumping losses and only slightly reduces "EGT"..............
 

Kelly = Troyer
"DYKE = DELTA JD2" = (Eventually)

"13B = ROTARY"_ Engine

Pulling off throttle is a good way to reduce total engine heat as in when you = have an oil cooling problem and EGTs. 

 

From a climb setting at 1600 on the EGT you are fuel cooling the engine = to good extent. This is a costly way to cool any engine. But no damage will = occur, and power will be good. So instead of fuel = cooling.........

the over-lean mixture cools by removing BTUs. Smaller fire. Less = heat. Better more thorough burn due to excess oxygen. Lower oil = temps. And so-on.

 

The rotor face is close to or in front of the spark plugs  longer than = a piston engine. More dwell. So less advance is needed, and there is more = time for the over-lean mixture to burn. Thus more efficient than a piston = engine? Not quite but very close. Add a monster ignition system and lean even = further.

 

That 1600 degrees is several hundred degrees from best power. That leaning to = lean of peak EGT must be done very quickly. As you turn the leaning knob or = pull on the cable, you will pass right through the very point we are trying to = avoid, best power and peak EGT. Or, pull of just a bit of throttle, then go = lean and put the throttle back up. One must not diddle at or near peak EGT. = Or, tune "B" for lean of peak and just flip the switch. =

 

This is not some new idea. If your piston engine has enough compression to run = lean of peak, it should be run so in cruise all of the time. All big radials use = fuel as fast as you can pour it out of a bucket. Were it not for lean of peak operation they had very limited range, and poor = payloads.

 

In the Fiat we never ran full throttle. I found on the dyno that more power was available just short of full throttle. My guess was that the butterflies = at slightly less than straight up and down, helped turn the mixture a bit. = An extra 3 HP every time.

 

Airplanes are dynamometers.

Take advantage. Make one change at a time. Record everything. Use SAE tables = to correct to sea level HP.

 

Lynn E. Hanover

------=_NextPart_000_0000_01CBC5F7.CCBE5210--