X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 24 Dec 2005 22:34:32 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m18.mx.aol.com ([64.12.138.208] verified) by logan.com (CommuniGate Pro SMTP 5.0.5) with ESMTP id 900654 for lml@lancaironline.net; Sat, 24 Dec 2005 22:05:35 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.208; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m18.mx.aol.com (mail_out_v38_r6.3.) id q.1ef.496e09c3 (4328) for ; Sat, 24 Dec 2005 22:04:46 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <1ef.496e09c3.30df664e@aol.com> X-Original-Date: Sat, 24 Dec 2005 22:04:46 EST Subject: Re: [LML] Re: Where has all the power gone? X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1135479886" X-Mailer: 9.0 Security Edition for Windows sub 5300 X-Spam-Flag: NO -------------------------------1135479886 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/24/2005 8:17:22 P.M. Central Standard Time, glcasey@adelphia.net writes: Lots of good comments on this issue, but I feel the need to clarify a few issues. First, there seems to be a consensus that EI provides a "hotter and longer" spark. sometimes true, but the most common EI product is a capacitive discharge (CD) system. The inductive (Kettering) system stores energy by using the inductance of the ignition coil and the spark occurs when the current in the primary is interrupted. These system, which include magnetos, are characterized by having a relatively slow voltage rise time, but a fairly long spark duration at a low current level. A CD system stores energy at high voltage in a capacitor and the spark occurs when this is discharged into the coil. Since the coil isn't required to store the total spark energy it can be smaller and of lower inductance. The result is a very fast rise time, high spark current and a very short duration. A short-duration spark works fine as long as there is a combustible mixture in the spark gap at the moment of the spark. CD systems work very well in engines that tend to foul plugs, which is why their initial popularity was in 2-stroke engines, but they typically don't work very well in engines that operate with "poor" mixture preparation, such as automotive engines running a lot of EGR. I see no problem using CD technology in aircraft engines as we don't typically operate at very light loads with EGR, except at idle. The CD system is far more electronically complex than an inductive system, which only requires an electronic switch to activate the coil. The automotive guys have spent billions researching ignition systems with the result that all automotive engines worldwide still use the original Kettering inductive system. The CD coils weigh less, but the electronics weigh more. I agree with Walter that the higher spark current will result in a faster initial burn, creating an effective timing advance compared to a conventional system. Gary, May be true for some. But LSE claims: <<<<< The PLASMA III is Light Speed Engineering's high performance continuous spark capacitor discharge ignition system. The Plasma III has a dual output stage which allows the spark to oscillate back and forth for a minimum of 20 degrees crankshaft rotation. This long duration spark allows further leaning without lean misfiring for added fuel efficiency it also noticeably increases horsepower output and engine smoothness. >>>>>> See: _http://www.lsecorp.com/Products/Ignition.htm_ (http://www.lsecorp.com/Products/Ignition.htm) I don't have the test equipment to check this - just the resulting performance. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Merry Christmas to all! -------------------------------1135479886 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 12/24/2005 8:17:22 P.M. Central Standard Time,=20 glcasey@adelphia.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Lots of=20 good comments on this issue, but I feel the need to clarify a 
fe= w=20 issues.  First, there seems to be a consensus that EI provides a = ;=20
"hotter and longer" spark.  sometimes true, but the most common=20 EI 
product is a capacitive discharge (CD) system.  The=20 inductive 
(Kettering) system stores energy by using the inductan= ce=20 of the 
ignition coil and the spark occurs when the current in th= e=20 primary is 
interrupted.  These system, which include magnet= os,=20 are characterized 
by having a relatively slow voltage rise time,= but=20 a fairly long 
spark duration at a low current level.  A CD=20 system stores energy at 
high voltage in a capacitor and the spar= k=20 occurs when this is 
discharged into the coil.  Since the co= il=20 isn't required to store the 
total spark energy it can be smaller= and=20 of lower inductance.  The 
result is a very fast rise time,=20= high=20 spark current and a very short 
duration.  A short-duration=20 spark works fine as long as there is a 
combustible mixture in th= e=20 spark gap at the moment of the spark.  CD 
systems work very= =20 well in engines that tend to foul plugs, which is 
why their init= ial=20 popularity was in 2-stroke engines, but they 
typically don't wor= k=20 very well in engines that operate with "poor" 
mixture preparatio= n,=20 such as automotive engines running a lot of 
EGR.  I see no=20 problem using CD technology in aircraft engines as we 
don't=20 typically operate at very light loads with EGR, except at =20
idle.  The CD system is far more electronically complex than an&n= bsp;=20
inductive system, which only requires an electronic switch to =20
activate the coil.  The automotive guys have spent billions = =20
researching ignition systems with the result that all automotive = =20
engines worldwide still use the original Kettering inductive=20 system.  
The CD coils weigh less, but the electronics weigh= =20 more.  I agree 
with Walter that the higher spark current wi= ll=20 result in a faster 
initial burn, creating an effective timing=20 advance compared to a 
conventional=20 system.
Gary,
 
May be true for some.  But LSE claims:
 
<<<<<
The PLASMA III is Light Speed Engineering's high=20 performance continuous spark capacitor discharge ignition system.  The=20 Plasma III has a dual output stage which allows the spark to oscillate back=20= and=20 forth for a minimum of 20 degrees crankshaft rotation.  This long durat= ion=20 spark allows further leaning without lean misfiring for added fuel efficienc= y it=20 also noticeably increases horsepower output and engine=20 smoothness.  
>>>>>>
 
See:
 
http://www.lsecorp.com= /Products/Ignition.htm
 
 
I don't have the test equipment to check this - just the resulting=20 performance.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Mer= ry=20 Christmas to all!



-------------------------------1135479886--