Posted for "Peter Field" <pfield.avn@gmail.com>:

Dear Lancair Drivers:



I've been following the discussion on stalls and spins and I want to add
some additional factual information purely for your personal consumption and
reflection.  Attached are excerpts from 10 different 1980-90 NASA flight
test final reports on a series of GA airplanes in which NASA evaluated the
use of cuffs on leading edges to improve the behavior of the test airplane
approaching the stall.  For various reasons the cuffs improved lateral
control entering the stall, but had the adverse effect of destabilizing the
aircraft once a fully developed spin was achieved.  Essentially, stall
behavior was improved at the sacrifice of spin recovery.  Cuffs on wing
leading edges are an add on design fix, the more elegant solution is
"washout," where the wing is twisted so the outer portions of the wing
always operate at a lower angle of attack.



To my knowledge, Lancair has never subjected any of their aircraft to a
fully developed spin matrix complete with appropriate instrumentation and a
spin recovery chute.  There is no FAA requirement for them to do so - it's
an Experimental Category airplane.  Early on they may have lightly touched
on such testing; but I have never seen any documentation on a fully
completed spin matrix, which would involve at least 160 spins at various
cg's and lateral loadings.  In my opinion, it would be highly risky to fool
around much beyond the stall in any Lancair - there is no documentation that
indicates any of these airplanes can always be recovered from a one turn
incipient phase spin or any fully developed spin.  Being good at spin
recovery isn't so much a matter of how skillful a pilot you are, it's a
matter of how many spins you've experienced in airplanes known to be
recoverable.  Being familiar with the stall characteristics of your own
airplane should be a matter of personal preference.  



Best regards,

Pete Field (LNC2)

USNTPS graduate & spin recovery instructor