X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 28 Dec 2005 22:50:25 -0500 Message-ID: X-Original-Return-Path: Received: from wind.imbris.com ([216.18.130.7] verified) by logan.com (CommuniGate Pro SMTP 5.0.5) with ESMTPS id 904181 for lml@lancaironline.net; Wed, 28 Dec 2005 15:04:31 -0500 Received-SPF: none receiver=logan.com; client-ip=216.18.130.7; envelope-from=brent@regandesigns.com Received: from [192.168.1.100] (vsat-148-63-101-227.c002.t7.mrt.starband.net [148.63.101.227]) (authenticated bits=0) by wind.imbris.com (8.12.11/8.12.11.S) with ESMTP id jBSK3Fx4076233 for ; Wed, 28 Dec 2005 12:03:38 -0800 (PST) (envelope-from brent@regandesigns.com) X-Original-Message-ID: <43B2EF7C.6040707@regandesigns.com> X-Original-Date: Wed, 28 Dec 2005 12:03:08 -0800 From: Brent Regan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: Where has all the power gone? Content-Type: multipart/alternative; boundary="------------020303080604080504050804" This is a multi-part message in MIME format. --------------020303080604080504050804 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Paul writes: "the rest (snip) seem to blindly advocate iron chunks strapped to the top/back of aircraft engines that disappeared from the rest of the internal combustion community decades ago." There are many times more IC engines using magneto ignition than battery driven ignition. Virtually every weed whacker, lawn mower, leaf blower, two stroke sport engine (atv, motorcycle, jet ski, snowmobile, etc), third world prime mover, Funny Car and Top Fuel drag racer uses magneto ignition. Before you wrinkle your nose up in that "I smell excrement" expression over my comparison of aircraft engines to leaf blowers I would point out that the operational requirements of a aircraft engine (air cooled, light weight, operation at high power settings, high gyroscopic loads) are much closer to that of a leaf blower than an automobile engine (water cooled, low power settings, minimum emissions, quiet). People tend to class engines by horsepower when the more accurate method is to class them by operational parameters. Aircraft engines, generators, marine engines and leaf blowers are at one category and automobile and motorcycle engines are in another. Demonstrated performance over millions of flight hours seems to be a solid foundation for "blind" advocacy. Paul is correct in the assertion that there are more mag failures than EI failures but he fails to consider the number of flight hours for both systems. I strongly suspect that the mag failure per flight hour rate is significantly lower that the EI failure per flight hour. "nothing has demonstrated lightning protection" Not according to the Feds. The recently adopted DO160E has two sections devoted to direct and indirect lightning effects. The "pin injection tests" subject the connector pins up to a 1600 volts /1600 amps pulse that the internal electronics must deal with. I was on the design team that was the first to certify equipment under these new standards (Chelton Flight Logic). "D-sub connectors are all over most homebuilts and work fine" D-Subs are crap. Anytime I have designed one into a system I have regretted that decision. Not long ago, on this list, there was discussion about failing D-Subs on EI systems. The only thing carppier than a D-Sub is a Faston (apologies to Bob N.). I had three Fastons on my plane, two have failed and, with the exception of landing lights, have been the only electrical system components to fail since first flight. The "gear" issue is, in fact, an impulse coupler issue and the impulse coupler can, and should, be eliminated with a mechanical or electronic starter vibrator connected to a magneto with a second set of "retard" points. Having cockpit adjustable timing scares the fudge out of me. Now there IS a throwback to the dawn of internal combustion. The pilot has no facility to detect impending engine meltdown yet has the ability to initiate it. As it is, pilots apparently can't be trusted to fatten up the mixture during decent. What makes you think that after advancing the timing for good cruise fuel economy the ape holding the stick will remember to retard the timing when going missed? The check list? About the time you are bringing up the gear in hard IMC the detonation that you had no way to detect has scattered two piston crowns. 600 feet AGL, hard IMC, no power, 30 knots over stall ... nice. If the EI system has a mechanism to prevent the above situation then it has the facility to eliminate the need for pilot adjustability. DUH..... No ignition system ever failed because its "Theory of Operation" failed. They fail because some minor component was poorly engineered or applied. The KISS principle, the Ockham's Razor of designing for reliability, dictates that the simplest system that meets the requirements is the best system. If it aint there it can't break. EI adds tremendous complexity in components, software and wiring as well as a dependency on the airframe's power system. BTW, a single alternator with two batteries is a single source electrical system with reserve storage capacity, not a triple source system. Please add a secondary alternator. In the past I designed a twin plug ignition system for a six cylinder air cooled engine (Porsche endurance racing) that operated flawlessly for five race seasons yet I elected to use a magneto system in my airplane, which has performed flawlessly for over 900 hours. The engine starts within five seconds and has never failed to start, even hot. I don't care how low the engine will idle because I never idle below 900 RPM since lower that that the turbos don't properly scavenge and the counterweight torsional balancer bushings' wear is accelerated. I always cruise in the flight levels except when I am racing (and winning) the Lancair Fly-In races so low altitude power doesn't seem to be an issue. Having said all that I would install an EI system in my airplane if that system addresses the reliability and robustness issues. So far, none of the systems on the market have cleared that bar. IMHO, can magnetos be improved? Yes. Have EI systems on the market demonstrated superiority in some aspects of operation? Yes. From an overall operational perspective, have current EI systems demonstrated superiority to magnetos? No. But by all means, if you have a different opinion don't let me stop you from sitting under the D-Sub connector of Damocles. My opinion may change, if you survive. Despite the rhetorical similarities, engines are not a religion. They are mechanical dynamic systems that must respond to reason. Clear, unbiased analytical thinking will bring you to the truth and sometimes that truth runs contrary to faith. Experimenting is advocated and encouraged but, for the love of low insurance premiums, use your brain. Wishing all a Happy, Prosperous and SAFE New Year. Brent Regan --------------020303080604080504050804 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Paul writes:
"the rest (snip) seem to blindly advocate iron chunks strapped to the top/back of aircraft engines that disappeared from the rest of the internal combustion community decades ago."

There are many times more IC engines using magneto ignition than battery driven ignition. Virtually every weed whacker, lawn mower, leaf blower, two stroke sport engine (atv, motorcycle, jet ski, snowmobile, etc), third world prime mover, Funny Car and Top Fuel drag racer uses magneto ignition.  Before you wrinkle your nose up in that "I smell excrement" expression over my comparison of aircraft engines to leaf blowers I would point out that the operational requirements of a aircraft engine (air cooled, light weight, operation at high power settings, high gyroscopic loads) are much closer to that of a leaf blower than an automobile engine (water cooled, low power settings, minimum emissions, quiet). People tend to class engines by horsepower when the more accurate method is to class them by operational parameters. Aircraft engines, generators, marine engines and leaf blowers are at one category and automobile and motorcycle engines are in another.

Demonstrated performance over millions of flight hours seems to be a solid foundation for "blind" advocacy. Paul is correct in the assertion that there are more mag failures than EI failures but he fails to consider the number of flight hours for both systems. I strongly suspect that the mag failure per flight hour rate is significantly lower that the EI failure per flight hour.

"nothing has demonstrated lightning protection"

Not according to the Feds. The recently adopted DO160E has two sections devoted to direct and indirect lightning effects. The "pin injection tests" subject the connector pins up to a 1600 volts /1600 amps pulse that the internal electronics must deal with. I was on the design team that was the first to certify equipment  under these new standards (Chelton Flight Logic).

"D-sub connectors are all over most homebuilts and work fine"

D-Subs are crap. Anytime I have designed one into a system I have regretted that decision. Not long ago, on this list, there was discussion about failing D-Subs on EI  systems. The only thing carppier than a D-Sub is a Faston (apologies to Bob N.). I had three Fastons on my plane, two have failed and, with the exception of landing lights,  have been the only electrical system components to fail since first flight.

The "gear" issue is, in fact, an impulse coupler issue and the impulse coupler can, and should, be eliminated with a mechanical or electronic starter vibrator connected to a magneto with a second set of "retard" points.

Having cockpit adjustable timing scares the fudge out of me. Now there IS a throwback to the dawn of internal combustion. The pilot has no facility to detect impending engine meltdown yet has the ability to initiate it. As it is, pilots apparently can't be trusted to fatten up the mixture during decent. What makes you think that after advancing the timing for good cruise fuel economy  the ape holding the stick will remember to retard the timing when going missed? The check list? About the time you are bringing up the gear in hard IMC the detonation that you had no way to detect has scattered two piston crowns. 600 feet AGL, hard IMC, no power, 30 knots over stall ... nice. If the EI system has a mechanism to prevent the above situation then it has the facility to eliminate the need for pilot adjustability. DUH.....

No ignition system ever failed because its "Theory of Operation" failed. They fail because some minor component  was poorly engineered or applied. The KISS principle, the Ockham's Razor of designing for reliability, dictates that the simplest system that meets the requirements is the best system. If it aint there it can't break. EI adds tremendous complexity in components, software and wiring as well as a dependency on the airframe's power system.  BTW, a single alternator with two batteries is a single source electrical system with reserve storage capacity, not a triple source system. Please add a secondary alternator.

In the past I designed a twin plug ignition system for a six cylinder air cooled engine (Porsche endurance racing) that operated flawlessly for five race seasons yet I elected to use a magneto system in my airplane, which has performed flawlessly for over 900 hours. The engine starts within five seconds and has never failed to start, even hot. I don't care how low the engine will idle because I never idle below 900 RPM since lower that that the turbos don't properly scavenge and the counterweight torsional balancer bushings' wear is accelerated. I always cruise in the flight levels except when I am racing (and winning) the Lancair Fly-In races so low altitude power doesn't seem to be an issue.

Having said all that I would install an EI system in my airplane if that system addresses the reliability and robustness issues. So far, none of the systems on the market have cleared that bar.  IMHO, can magnetos be improved? Yes. Have EI systems on the market demonstrated superiority in some aspects of operation? Yes.  From an overall operational perspective, have current EI systems demonstrated superiority to magnetos? No.  But by all means, if you have a different opinion don't let me stop you from sitting under the D-Sub connector of Damocles. My opinion may change, if you survive.

Despite the rhetorical similarities, engines are not a religion. They are mechanical dynamic systems that must respond to reason. Clear, unbiased analytical thinking will bring you to the truth and sometimes that truth runs contrary to faith. Experimenting is advocated and encouraged but, for the love of low insurance premiums, use your brain.

Wishing all a Happy, Prosperous and SAFE New Year.

Brent Regan



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