Date: Sat, 20 Oct 2001 10:13:34 -0400
From: James Frantz <LFrantz@compuserve.com>
Subject: Ice and other contaminants
Sender: James Frantz <LFrantz@compuserve.com>
To: "INTERNET:lancair.list@olsusa.com" <lancair.list@olsusa.com>
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>What icing experiences have others encountered?<

In cruise with clean wings, my AOA indicates 1.8 degrees.  When I fly into
light rain, get the wings contaminated with bugs, or start picking up light
ice, I notice two indications. The AOA increases to about 2.1 degrees AOA
followed by about a 5 knot decrease in IAS.  The relatively small gap
forward of my rudder and elevator counter weight make me nervious about
accepting any significant ice build up.

Our 360 airfoil is classed as "noncritical laminar" which means it will
still fly even when the laminar portion of the wing goes turbulent flow. 
In laymen terms, that means that a midair with a few bugs, light icing or
rain will not cause our wings to stop creating lift.  Some racing aircraft
must be ground transported to the race becasue they have "critical laminar"
airfoils.  The IV wing is classed as a "highly laminar flow" airfoil.  The
airfoils on the airline heavy iron and most light aircraft are classed as
"turbulent flow" meaning there is virtually no laminar flow.

I clean the wing leading edges before departure and avoid ice and bugs to
get there sooner.  I've found that flying through rain slows me down but
the effect goes away as soon as I fly out of the rain. Same results for
light ice. Degradation in performance due to bug contaminant is permanent
for the duration of the flight. Ouch!!!

With our high performance Lancairs, here in MN, ice is easily avoided, bugs
are impossible to avoid! My bug avoidance policy is to minimize flight at
low altitudes and departures before sunrise or at dusk. Low atlitude scenic
flights are best done at the end of the flight rather than the beginning.

Jim Frantz 

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Please send your photos and drawings to marvkaye@olsusa.com.
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