Message-ID: <39E1D92F.99BEDE8D@mc.net>
Date: Mon, 09 Oct 2000 09:41:51 -0500
From: jerry@mc.net
To: lancair.list@olsusa.com
Subject: Re: Hard Landing
References: <20001009044649.AAA22016@ns1.olsusa.com> <002c01c031e0$6e59fb40$dd6eaccf@oemcomputer>
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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To the List:

This message is presented to introduce added info to our thought processes
when flying this "fighter like" airplane with a high wing load.  It is not
intended to pick anybody's flying techniques apart or to be 20/20
hindsight.  I'm very happy no one was injured and glad to learn Hal is
"hanging in there" and ready to fly again.

As I recall the sequence of events started with a steep approach to
compensate for the possibility of the engine quitting.  To off-set the steep
approach and reduce the possibility of a speed increase ... a greater flap
setting was used.  This configuration doesn't require much thrust (rpm) to
maintain speed.  As the touchdown flare is started, in this configuration,
the wing is asked to increase lift on the order of 1/10 to 1/5 of a "G". 
This request induces drag while, at the same time, the greater flap setting
is adding parasitic drag.  This increased drag decays airspeed quickly, and
at a time when more thrust is needed to create the energy to rotate through
the flare.
Once the nose is rotated through and is pointing above the horizon the
rotation is complete and the thrust can usually be in idle.  However, it can
happen where the rotation is complete and the descent is not arrested ...
that's when the the surprises grab us all.

Add to the above scenario the possibility of the touchdown end of the runway
being on a hill with a drop off at the approach end of the runway.  The so
called headwind or quartering crosswind can now set up a wind component, in
the vertical plane, which wants to push the airplane below a desired glide
path or at least increase the vertical component to the glide path.  Now the
thrust requirements, for flare, are going to be even greater because of the
more vertical component induced by the wind.

Written by one who is experienced in vertical component landings, some of
which could leap tall buildings in a single bound.

Jerry Grimmonpre'   LNC2
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LML website:   http://www.olsusa.com/Users/Mkaye/maillist.html
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Please send your photos and drawings to marvkaye@olsusa.com.
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