Message-ID: <004301c03155$22807900$263132cf@tcac.net>
From: "johnlasher" <johnlasher@msn.com>
To: <lancair.list@olsusa.com>
References: <c5.9ddc318.27107a38@aol.com>
Subject: Re: Lancair IV-P Heating problems climbing through FL 190
Date: Sun, 8 Oct 2000 13:25:27 -0500
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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Scott Krueger wrote>
> If ignition operation/timing can lead to high altitude temperature
problems,
> consider the followings questions in additiion to Brent's:
>
> 1) Klaus' specs (www.Lsecorp.com) doesn't mention an altitude range over
> which his electronic ignition systems were tested.  Thin air doesn't
provide
> the same "insulation" effect as more dense air.  Any cross-fire between
> components or harness?

This is one of the reasons that EI is an improvement over a mag. There are
no points or distributors. There is an electromagnetic pickup on the prop
hub that sends pulses to a controller which intern fires two plugs
simultaneously at 120 degree intervals. One of the two plugs being fired
simultaneously is 24 DBTDC in the compression stroke while the other is 180
degree opposed in the exhaust stroke (a wasted spark - but then no
distributor is needed). If you do the math, then all 6 cylinders are fired
24 DBTDC on the compression stroke every 720 degrees of rotation.

> 2) Because of the ease which charges can jump gaps at high altitudes,
> magnetos should be pressurized to eliminate timing problems.  Are yours
and
> if so, is the pressurization working?

My mag is pressurized and was overhauled and checked within the last 100
hours by Consolidated Fuel Systems. The EI doesn't require pressurization.
Klaus has tested his EI systems I believe up to altitudes of 29,000 feet.

I'm convinced that the EI is better than the mag and could easily exceed the
TBO of the engine without maintenance except for the spark plugs. However,
having only one along with a conventional mag can present possible problems
in our high altitude IV-Ps as was so nicely outlined by Brent Reagan in one
of his replies to my heating problems. The problem with having two, is that
they are both dependent on the electrical system - requiring a backup
battery system of some sort. I probably should go to two EIs.

John R. Deakin has a great 4 part series of articles on "Those
Fire-Breathing Turbos" on
http://www.avweb.com/articles/pelperch/perchlinks.html . These articles
should be read by all IV-P drivers. They are filled with factual information
and graphs that will make all of us more knowledgeable and safer pilots. In
the Part 2 article he writes about "The Future":
   "There are persistent rumors of a number of improvements in store. Chief
among them is an electronic ignition system that is far superior to anything
in any engine (car or aircraft) today. It will look directly at each
combustion event, and modify the spark timing as needed for the succeeding
event. This will produce the ideal pressure event for best power, regardless
of power settings, RPM, ambient pressure/temperature, or fuel octane. There
is every reason to believe this system will allow all our aircraft engines
to run at full rated power on 94- to 98-octane fuel, with NO lead. That will
solve the aviation fuel crisis overnight."

John Lasher
N411WB


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