X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 28 Dec 2005 01:17:58 -0500 Message-ID: X-Original-Return-Path: Received: from secure5.liveoakhosting.com ([64.49.254.21] verified) by logan.com (CommuniGate Pro SMTP 5.0.5) with ESMTPS id 902743 for lml@lancaironline.net; Tue, 27 Dec 2005 11:19:23 -0500 Received-SPF: none receiver=logan.com; client-ip=64.49.254.21; envelope-from=walter@advancedpilot.com Received: (qmail 2905 invoked from network); 27 Dec 2005 10:18:34 -0600 Received: from 216-107-97-170.wan.networktel.net (HELO ?10.0.1.4?) (216.107.97.170) by rs5.liveoakhosting.com with SMTP; 27 Dec 2005 10:18:34 -0600 Mime-Version: 1.0 (Apple Message framework v623) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-4-626805934 X-Original-Message-Id: From: Walter Atkinson Subject: Re: [LML] Re: Where has all the power gone? X-Original-Date: Tue, 27 Dec 2005 10:18:32 -0600 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.623) --Apple-Mail-4-626805934 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1; format=flowed Scott: ** I meant that you will always=A0comment that in some way anything = other=20 than mags=A0leads to engine problems. And, it is always general so that=20= the reader could only conclude not=A0to try existing experimental=20 products for fear of something bad happening to their experimental=20 airplane and experimental engine.=A0** I don't think I have done that. =A0I, too, am looking forward to getting=20= rid of my mags. There are some things about electronic ignitions and=20 plying with timing that can present problems. That has been the thrust=20= of my comments. **Given the coarse hand controls we fly by - throttle, prop and mixture=20= - It would be nice to hear practical information on how we could use=20 "data" from the crummy engine monitors we have (no pressure monitor)=A0-=20= GPH, CHT and EGT -=A0to determine the quality of the engine operation.=A0=20= Those of us leaping into a pit of lions by installing advanced ignition=20= systems generally see positive results -=A0higher horsepower felt in the=20= seat-of-pants dyno, fuel savings at lower power settings, easier starts=20= and higher speeds.=A0 We also see lower EGTs and higher CHTs, all=20 explained in the product sales brochure.=A0** Lower EGTs and higher CHTs are compatible with advanced timing as I=20 have alluded to. These are not positive changes in my mind and are not=20= compatible with longevity concerns. Seat of the pants dynos have been=20= known to be waaaay out of calibration. The measured HP does not change=20= significantly with changes in timing at high power settings. The=20 stress on the engine does. And, that is independent of how the spark=20 is generated. =A0 **Well, a Google search using: crankshaft harmonics electronic=20 ignition=A0aircraft engine=A0 did not turn up anything.=A0 ** As expected. There is only one source for that information and they=20 are holding it as proprietary at this time. I was quite certain that=20 you, nor anyone else would have known anything about those issues. It=20= does not change the fact that there are significant effects of the law=20= of unintended consequences in varying ignition systems that have been=20 noted by researchers who have not yet published the findings. The=20 point is that this i, indeed, an area of an experimental nature. For=20 example, as noted above, the lower EGTs claimed to be a good effect of=20= EIs is NOT a good thing. It's the result of an alteration of the=20 effective timing. =A0 **The facts don't upset me at all.=A0 Indeed, some electronic=20 ignitions=A0do provide for a retarded spark at high power settings.=A0=20= Usually, us experimenters make the comment "Gee,=A0takeoff works better=20= with a retarded base timing." This seems to be the case on a NA engine=20= with CRs greater than 8.5.=A0 If only we could measure this - even=20 indirectly with the current engine monitors.** Ah, but you CAN. If the EGTs went UP and the CHTs went down after a=20 timing change during takeoff, it would tell you that you have retarded=20= the effective timing. =A0 Again, still waiting for the reference on why the reduced combustion=20 mixture pressure achieved at higher altitudes where WOT yields MAPs=20 below 21" would require greater voltage to arc the plug than that=20 required at sea level where the MAP might be 30" (same compression=20 ratio). =A0 I corrected my mistake in another post. I also thanked the person who=20= pointed out my error with a reference. I guess you missed that. Walter= --Apple-Mail-4-626805934 Content-Transfer-Encoding: quoted-printable Content-Type: text/enriched; charset=ISO-8859-1 Scott: **Arial I meant that you will always=A0comment that in some way anything other than mags=A0leads to engine problems. And, it is always general so that the reader could only conclude not=A0to try existing experimental products for fear of something bad happening to their experimental airplane and experimental engine.=A0** I don't think I have done that. =A0I, too, am looking forward to getting rid of my mags. There are some things about electronic ignitions and plying with timing that can present problems. That has been the thrust of my comments. Arial**Given the coarse hand controls we fly by - throttle, prop and mixture - It would be nice to hear practical information on how we could use "data" from the crummy engine monitors we have (no pressure monitor)=A0- GPH, CHT and EGT -=A0to determine the quality of the engine operation.=A0 Those of us leaping into a pit of lions by installing advanced ignition systems generally see positive results -=A0higher horsepower felt in the seat-of-pants dyno, fuel savings at lower power settings, easier starts and higher speeds.=A0 We also see lower EGTs and higher CHTs, all explained in the product sales brochure.=A0** Lower EGTs and higher CHTs are compatible with advanced timing as I have alluded to. These are not positive changes in my mind and are not compatible with longevity concerns. Seat of the pants dynos have been known to be waaaay out of calibration. The measured HP does not change significantly with changes in timing at high power settings. The stress on the engine does. And, that is independent of how the spark is generated. Arial=A0 Arial**Well, a Google search using:=20 Arialcrankshaft harmonics electronic ignition=A0aircraft engine=A0 Arialdid not turn up anything.=A0 ** As expected. There is only one source for that information and they are holding it as proprietary at this time. I was quite certain that you, nor anyone else would have known anything about those issues. It does not change the fact that there are significant effects of the law of unintended consequences in varying ignition systems that have been noted by researchers who have not yet published the findings. The point is that this i, indeed, an area of an experimental nature. For example, as noted above, the lower EGTs claimed to be a good effect of EIs is NOT a good thing. It's the result of an alteration of the effective timing. Arial=A0 Arial**The facts don't upset me at all.=A0 Indeed, some electronic ignitions=A0do provide for a retarded spark at high power settings.=A0 Usually, us experimenters make the comment "Gee,=A0takeoff works better with a retarded base timing." This seems to be the case on a NA engine with CRs greater than 8.5.=A0 If only we could measure this - even indirectly with the current engine monitors.** Ah, but you CAN. If the EGTs went UP and the CHTs went down after a timing change during takeoff, it would tell you that you have retarded the effective timing. Arial=A0 ArialAgain, still waiting for the reference on why the reduced combustion mixture pressure achieved at higher altitudes where WOT yields MAPs below 21" would require greater voltage to arc the plug than that required at sea level where the MAP might be 30" (same compression ratio). Arial=A0 I corrected my mistake in another post. I also thanked the person who pointed out my error with a reference. I guess you missed that. Walter= --Apple-Mail-4-626805934--