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From: Walter Atkinson <walter@advancedpilot.com>
Subject: Re: [LML] Re: FW: Compression, boost, and detonation
X-Original-Date: Fri, 28 Apr 2006 22:55:29 -0500
X-Original-To: "Lancair Mailing List" <lml@lancaironline.net>
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Rick:


**Is pre-ignition the "exact same phenomenon" as auto-ignition, but=20
self-initiated before the spark event?**

No.

**Does pre-ignition "need" a "glowing ember" or can it be induced by=20
pressure & temp alone?**

It needs a flash point like a spark plug that's glowing or a helicoil=20
tang.
=A0
**is it possible to have both pre-ignition and detonation?**

Yes.=A0
=A0
**Does detonation tend to be aggravated or lessened if you were to turn=20=

one of the mags off?**

Yes, that will frequently stop the detonation.

**I have heard (OWT?) about bore size being a contributing factor to=20
detonation before, but I=92ve never really understood the mechanism=20
behind why bore size would aggravate detonation.**

One would think that bore size would affect the time it takes for the=20
flame front to cross the cylinder and require a longer latency to=20
retard any detonation tendency.  I haven't studied that in Taylor, but=20=

my guess is that it's a minor factor.
=A0
**Has George done any testing with more than two spark plugs on the=20
large bore engines?=A0**

No, I don't think so.

Walter=

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Rick:



**<fixed><fontfamily><param>Courier New</param><x-tad-bigger>Is
pre-ignition the "exact same phenomenon" as auto-ignition, but
self-initiated before the spark event?</x-tad-bigger><x-tad-bigger>**


No.

</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>**</x-tad-bigger><x-tad-bigger>Does
pre-ignition "need" a "glowing ember" or can it be induced by pressure
& temp alone?</x-tad-bigger><x-tad-bigger>** =20


It needs a flash point like a spark plug that's glowing or a helicoil
tang.</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>=A0</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>**</x-tad-bigger><x-tad-bigger>is
it possible to have both pre-ignition and
detonation?</x-tad-bigger><x-tad-bigger>**


Yes.</x-tad-bigger><x-tad-bigger>=A0</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>=A0</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>**</x-tad-bigger><x-tad-bigger>Does
detonation tend to be aggravated or lessened if you were to turn one
of the mags off?</x-tad-bigger><x-tad-bigger>**


Yes, that will frequently stop the detonation.

</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>**</x-tad-bigger><x-tad-bigger>I
have heard (OWT?) about bore size being a contributing factor to
detonation before, but I=92ve never really understood the mechanism
behind why bore size would aggravate
detonation.</x-tad-bigger><x-tad-bigger>**


One would think that bore size would affect the time it takes for the
flame front to cross the cylinder and require a longer latency to
retard any detonation tendency.  I haven't studied that in Taylor, but
my guess is that it's a minor =
factor.</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>=A0</x-tad-bigger></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><x-tad-bigger>**</x-tad-bigger><x-tad-bigger>Has
George done any testing with more than two spark plugs on the large
bore engines?=A0</x-tad-bigger><x-tad-bigger>**


No, I don't think so.


Walter</x-tad-bigger></fontfamily></fixed>=

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