X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nm29-vm0.access.bullet.mail.sp2.yahoo.com ([98.139.44.192] verified) by logan.com (CommuniGate Pro SMTP 5.4c2o) with SMTP id 4892758 for flyrotary@lancaironline.net; Sun, 06 Mar 2011 12:43:38 -0500 Received-SPF: none receiver=logan.com; client-ip=98.139.44.192; envelope-from=keltro@att.net Received: from [98.139.44.101] by nm29.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 Mar 2011 17:43:01 -0000 Received: from [98.139.44.81] by tm6.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 Mar 2011 17:43:01 -0000 Received: from [127.0.0.1] by omp1018.access.mail.sp2.yahoo.com with NNFMP; 06 Mar 2011 17:43:01 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 637109.91695.bm@omp1018.access.mail.sp2.yahoo.com Received: (qmail 30456 invoked by uid 60001); 6 Mar 2011 17:43:01 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=att.net; s=s1024; t=1299433381; bh=QMUq5t9933dnH+LO2uFoidzo5GXPQ47mFju41lDtQQ8=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type; b=BMx/C0oRjis7HsxhmX5dIpqgAsasQEhXNMyrNBECOi2n47Q8MtTegdqQPoN6yJMM8VB1nv3KYVI+A657vQWmjcV/VX6jmLnOR9AGkzT2hln6XK6LK4lvSMTkUxvJ9n7ilvoHvMwHvmmkJ4ULdOlMmtjLq/5uN8quSzc3Cfnan5A= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=att.net; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type; b=hCNhKulEuMP5hzl+7UmmKW6hWcwkDCzPhFXT3xTm3RPBWClwdJxmPbOdLcgZwApoEuPApNQCSmog2oLLJFmFUE2P6vttWhOS97EM2S8Jd8DjkWab+r+Ow1rEJKkK3RIKjAb/IHVoXUUtT4p8mLrCtZhGQMWROxvASrOiWLsWxK0=; Message-ID: <358883.13752.qm@web83907.mail.sp1.yahoo.com> X-YMail-OSG: SCVNSgUVM1mdfhdTR1Xmvk9jM7RmGL4.1b0KyJHtk.XYFF6 1b_akuPyrJHgG1s4W9JUVTIaoynx.RDO6huLaUXTvc8SMjXY5Wnxp6bjZlZl Rb86kqHyf9Up7k5dX.u_0o7xYjsd.HaisHTHJkFBgilMGRCQw2ToH6kOFiYZ YDX9ZCOzNSBdbHXFAxCNpY2jYQZuUba_kN02ElmgeUW3aTTeLaPohiaOPcHv r84JHI9TBxu5bCDsawWtwe8WhmRQibfzC6byqKaqvhDSaNuSg4f8v8c59EQH x.nDZ9T3xdlAl Received: from [208.114.44.149] by web83907.mail.sp1.yahoo.com via HTTP; Sun, 06 Mar 2011 09:43:01 PST X-Mailer: YahooMailRC/559 YahooMailWebService/0.8.109.292656 Date: Sun, 6 Mar 2011 09:43:01 -0800 (PST) From: Kelly Troyer Subject: For Lynn_Effect of Leaning & Timing for Turbo Rotary To: Rotary motors in aircraft Cc: CozyGirrrl@aol.com MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-252765832-1299433381=:13752" --0-252765832-1299433381=:13752 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable From: William Wilson Add to Contacts =0ATo: Rotary m= otors in aircraft =0A______________________= __________=0A=0AKelly Troyer wrote:=0A=0A=0A"I just remembered one other ti= dbit of info from our rotary guru =0ALynn.........One of=0Ahis informative = posts on fuel and the effects of octane ratings stated that as =0Ayou lean= =0Athe auto fuel that many of us use (87 to 91 octane) that the flame front= is =0Aslowed and=0Athis mimics the effect of lead in fuel"=0A=0A=0A=A0Will= iam wrote:=0A=0AGenerally, leaner mixture increases the risk of detonation,= regardless of octane =0Aor presence of lead.=A0 On a naturally aspirated r= otary it doesn't usually matter =0Amuch.=0A=0AI find this page to be an exc= ellent reference for the effects of octane:=0Ahttp://www.turborx7.com/fuel.= htm=0A=0A=0A=A0=A0 Kelly Troyer write :=0A=0A"One other point that I forgot= to mention was ignition timing..........It is my =0Aunderstanding=0Athat t= urboed engines should not use excessive timing advance and that the higher = =0Athe=0Aboost the less timing advance is needed (or wise).........As I rec= all ignition =0Atiming as high=0Aas 27 + degrees BTDC has/is used for natur= ally aspirated Rotarys"=0A=0A=A0=A0 William wrote:=0A=0AI think the confusi= on here is between talking about the timing at idle and the =0Atiming at hi= gh RPM.=A0 When you set the timing you are usually setting the idle =0Atimi= ng, then the ECU adds a certain amount of advance based on the RPM, =0Atemp= erature, whatever.=A0 10 degrees is probably the idle setting, not the maxi= mum =0Aadvance, whereas the 27+ is probably the maximum advance (maximum ad= vance in my =0Acar is about 35).=0A=0A=0AThis is an excerpt from...........= .http://www.turborx7.com/fuel.htm=0A=0A=0A=A0What is the effect of changing= the air-fuel ratio?=0A=0ATraditionally, the greatest tendency to knock was= near 13.5:1 air-fuel ratio, =0Abut was very engine specific. Modern engine= s, with engine management systems, =0Anow have their maximum octane require= ment near to 14.5:1. For a given engine =0Ausing gasoline, the relationship= between thermal efficiency, air-fuel ratio, and =0Apower is complex. Stoic= hiometric combustion (air-fuel =0A=0Aratio =3D 14.7:1 for a typical non-oxy= genated gasoline) is neither maximum power - =0Awhich occurs around air-fue= l 12-13:1 (Rich), nor maximum thermal efficiency - =0Awhich occurs around a= ir-fuel 16-18:1 (Lean). The air-fuel ratio is controlled at =0Apart throttl= e by a closed loop system using the oxygen sensor in the exhaust. =0AConven= tionally, enrichment for maximum power air-fuel ratio is used during full = =0Athrottle operation to reduce knocking while providing better drivability= [38]. =0AAn average increase of 2 (R+M)/2 ON is required for each 1.0 incr= ease (leaning) =0Aof the air-fuel ratio [111]. If the mixture is weakened, = the flame speed is =0Areduced, consequently less heat is converted to mecha= nical energy, leaving heat =0Ain the cylinder walls and head, potentially i= nducing knock. It is possible to =0Aweaken the mixture sufficiently that th= e flame is still present when the inlet =0Avalve opens again, resulting in = backfiring.=0A=0A=A0=0AWhat is the effect of changing the ignition timing?= =0A=0AThe tendency to knock increases as spark advance is increased. For an= engine =0Awith recommended 6 degrees BTDC (Before Top Dead Center) timing = and 93 octane =0Afuel, retarding the spark 4 degrees lowers the octane requ= irement to 91, whereas =0Aadvancing it 8 degrees requires 96 octane fuel [2= 7]. It should be noted this =0Arequirement depends on engine design. If you= advance the spark, the flame front =0Astarts earlier, and the end gases st= art forming earlier in the cycle, providing =0Amore time for the autoigniti= ng species to form before the piston reaches the =0Aoptimum position for po= wer delivery, as determined by the normal flame front =0Apropagation. It be= comes a race between the flame front and decomposition of the =0Aincreasing= ly squashed end gases. High octane fuels produce end gases that take =0Alon= ger to autoignite, so the good flame front reaches and consumes them =0Apro= perly. =0A=0A=0AThe ignition advance map is partly determined by the fuel t= he engine is intended =0Ato use. The timing of the spark is advanced suffic= iently to ensure that the =0Afuel-air mixture burns in such a way that maxi= mum pressure of the burning charge =0Ais about 15-20 degree after TDC. Knoc= k will occur before this point, usually in =0Athe late compression - early = power stroke period.=0AThe engine management system uses ignition timing as= one of the major variables =0Athat is adjusted if knock is detected. If ve= ry low octane fuels are used =0A(several octane numbers below the vehicle's= requirement at optimal settings), =0Aboth performance and fuel economy wil= l decrease.=0A=0AThe actual Octane Number Requirement depends on the engine= design, but for some =0A1978 vehicles using standard fuels, the following = (R+M)/2 Octane Requirements =0Awere measured. "Standard" is the recommended= ignition timing for the engine, =0Aprobably a few degrees BTDC [38].=0A=0A= Basic Ignition Timing=0AVehicle Retarded 5 degrees Standard Advanced 5 degr= ees=0AA 88 91 93=0AB 86 90.5 94.5=0AC 85.5 88 90=0AD 84 87.5 91=0AE 82.5 87= 90 =0A=0AThe actual ignition timing to achieve the maximum pressure from n= ormal =0Acombustion of gasoline will depend mainly on the speed of the engi= ne and the =0Aflame propagation rates in the engine. Knock increases the ra= te of the pressure =0Arise, thus superimposing additional pressure on the n= ormal combustion pressure =0Arise. The knock actually rapidly resonates aro= und the chamber, creating a series =0Aof abnormal sharp spikes on the press= ure diagram. The normal flame speed is =0Afairly consistent for most gasoli= ne HCs, regardless of octane rating, but the =0Aflame speed is affected by = stoichiometry. Note that the flame speeds in this FAQ =0Aare not the actual= engine flame speeds. A 12:1 CR gasoline engine at 1500 rpm =0Awould have a= flame speed of about 16.5 m/s, and a similar hydrogen engine yields =0A48.= 3 m/s, but such engine flame speeds are also very dependent on stoichiometr= y. =0A=0A=0A=0ALynn,=0A=0A=A0=A0=A0 From your previous posts on this subjec= t it seems that the Rotary does not =0Areact in the exact=A0same way as a t= ypical=0Apiston engine to leaning and or timing changes...................W= illiam has =0Aused as reference a very detailed piece from=0Ahttp://www.tur= borx7.com/fuel.htm=A0(excerpt above) that he feels challenges =0Aprevious i= nfo that you have posted and=0Athat I mentioned from memory so I=A0may not = have related it =0Aaccurately...........Would appreciate=A0your additional = thoughts=0Aabout this and any corrections if I misspoke.........(Tracy post= ed recently that =0Ahis EC2-3 does retard ignition timing as=0Aboost increa= ses < up to12 degrees>)................=0A=0AThanks,=0A=0A=A0Kelly Troyer= =0A"DYKE DELTA JD2" (Eventually)=0A"13B ROTARY"_ Engine=0A"RWS"_RD1C/EC2/EM= 2=0A"MISTRAL"_Backplate/Oil Manifold=0A"TURBONETICS"_TO4E50 Turbo --0-252765832-1299433381=:13752 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
=0A
=0A
=0A=0A=0A= =0A=0A=0A=0A=0A
From:=0A
=0A
William Wilson <fluffysheap@gmail.com>
Add to Contacts
To= :<= FONT color=3D#222222>Rotary motors in aircraft <flyrotary@= lancaironline.net> =0A
=0A
=0A=0A
=0A=0AKelly Troyer wrote:
=0A
 
=0A
"I just remembered o= ne other tidbit of info from our rotary guru Lynn.........One of
his inf= ormative posts on fuel and the effects of octa= ne ratings stated that as you lean
the auto fuel that many of us = use (87 to 91 octane) that the flame front is slowed and
this mimics the= effect of lead in fuel"
=0A
 
=0A
 William= wrote:
=0A

Generally, leaner mixture increases the risk of de= tonation, regardless of octane or presence of lead.  On a naturally as= pirated rotary it doesn't usually matter much.

I find this page to b= e an excellent reference for the effects of octane:
http://www.turborx7.com/fuel.htm
<= /DIV>=0A

   Kelly Troyer write :
=0A
 =0A
"One other point that I forgot to ment= ion was ignition timing..........It is my understanding
that turboed eng= ines should not use excessive timing advance and that the higher the
boost the less timing advance is needed (o= r wise).........As I recall ignition timing as high
as 27 + degrees BTDC= has/is used for naturally aspirated Rotarys"
=0A
  = William wrote:
=0A

I think the confusion here is between talk= ing about the timing at idle and the timing at high RPM.  When you set= the timing you are usually setting the idle timing, then the ECU adds a ce= rtain amount of advance based on the RPM, temperature, whatever.  10 d= egrees is probably the idle setting, not the maximum advance, whereas the 2= 7+ is probably the maximum advance (maximum advance in my car is about 35).=
=0A
 
=0A
This is an excerpt from........= ....ht= tp://www.turborx7.com/fuel.htm

=0A
 = ;What is the effect of changing the a= ir-fuel ratio?

Traditionally, the greatest= tendency to knock was near 13.5:1 air-fuel ratio, but was very engine spec= ific. Modern engines, with engine management systems, now have their maximu= m octane requirement near to 14.5:1. For a given engine using gasoline, the= relationship between thermal efficiency, air-fuel ratio, and power is comp= lex. Stoichiometric combustion (air-fuel
ratio =3D 14.7:1 for a typical= non-oxygenated gasoline) is neither maximum power - which occurs around ai= r-fuel 12-13:1 (Rich), nor maximum thermal efficiency - which occurs around= air-fuel 16-18:1 (Lean). The air-fuel ratio is controlled at part throttle= by a closed loop system using the oxygen sensor in the exhaust. Convention= ally, enrichment for maximum power air-fuel ratio is used during full throt= tle operation to reduce knocking while providing better drivability [38]. An average increase of 2 (R+M)/2 ON is required for each= 1.0 increase (leaning) of the air-fuel ratio [111]. If the mixture is weak= ened, the flame speed is reduced, consequently less heat is converted to me= chanical energy, leaving heat in the cylinder walls and head, potentially i= nducing knock. It is possible to weaken the mixture sufficiently that the f= lame is still present when the inlet valve opens again, resulting in backfi= ring.

 
=0A
=0A

What is the effect of changing the ignition ti= ming?

The tendency to knock increases as s= park advance is increased. For an engine with recommended 6 degrees BTDC (B= efore Top Dead Center) timing and 93 octane fuel, retarding the spark 4 deg= rees lowers the octane requirement to 91, whereas advancing it 8 degrees re= quires 96 octane fuel [27]. It should be noted this requirement depends on = engine design. If you advance the spark, the flame front starts earlier, an= d the end gases start forming earlier in the cycle, providing more time for= the autoigniting species to form before the piston reaches the optimum pos= ition for power delivery, as determined by the normal flame front propagati= on. It becomes a race between the flame front and decomposition of the incr= easingly squashed end gases. High octane fuels produce end gases that take = longer to autoignite, so the good flame front reaches and consumes them properly.

The ignition advance map is pa= rtly determined by the fuel the engine is intended to use. The timing of th= e spark is advanced sufficiently to ensure that the fuel-air mixture burns = in such a way that maximum pressure of the burning charge is about 15-20 de= gree after TDC. Knock will occur before this point, usually in the late com= pression - early power stroke period.
The engine management system uses = ignition timing as one of the major variables that is adjusted if knock is = detected. If very low octane fuels are used (several octane numbers below t= he vehicle's requirement at optimal settings), both performance and fuel ec= onomy will decrease.

The actual Octane Number Requirement depends on= the engine design, but for some 1978 vehicles using standard fuels, the fo= llowing (R+M)/2 Octane Requirements were measured. "Standard" is the recomm= ended ignition timing for the engine, probably a few degrees BTDC [38].

Basic Ignition Timing
Vehicle Retarded 5 degrees Standard = Advanced 5 degrees
A 88 91 93
B 86 90.5 94.5
C 85.5 88 90
D 84 = 87.5 91
E 82.5 87 90

The actual ignition timing to achieve the m= aximum pressure from normal combustion of gasoline will depend mainly on th= e speed of the engine and the flame propagation rates in the engine. Knock = increases the rate of the pressure rise, thus superimposing additional pres= sure on the normal combustion pressure rise. The knock actually rapidly res= onates around the chamber, creating a series of abnormal sharp spikes on th= e pressure diagram. The normal flame speed is fairly consistent for most ga= soline HCs, regardless of octane rating, but the flame speed is affected by= stoichiometry. Note that the flame speeds in this FAQ are not the actual e= ngine flame speeds. A 12:1 CR gasoline engine at 1500 rpm would have a flam= e speed of about 16.5 m/s, and a similar hydrogen engine yields 48.3 m/s, but such engine flame speeds are also very dependent on stoichiometry= .

=0A
 
=0A
Lynn,
=0A 
=0A
    From your previous posts on this s= ubject it seems that the Rotary does not react in the exact same way a= s a typical
=0A
piston engine to leaning and or timing changes....= ...............William has used as reference a very detailed piece from=0A
http://www.turborx7.com/fuel.htm (excerpt above)= that he feels challenges previous info that you have posted and
=0Athat I mentioned from memory so I may not have related it accuratel= y...........Would appreciate your additional thoughts
=0A
abo= ut this and any corrections if I misspoke.........(Tracy posted recently th= at his EC2-3 does retard ignition timing as
=0A
boost increases &l= t; up to12 degrees>)................
=0A
 
=0A
Th= anks,
=0A
 
=0A
 Kelly Troyer
"DYKE DELTA JD2" (Eventually)
=0A

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backpl= ate/Oil Manifold

=0A

"TURBONETICS"_TO4E50 Turbo

=0A
--0-252765832-1299433381=:13752--