Posted for "Dominic V. Crain"
<domcrain@tpg.com.au>:
Bill, May I respectfully suggest that after you exit the aircraft after the
first flight you kiss the AIRCRAFT - not the ground. It will be the AIRCRAFT, not the ground, which you can
thank. Now, in relation to stalls, it never ceases to amaze me that some pilots want to fly an aircraft near the stall
following type training. You may rest assured that the philosophy of stall training is designed to ensure pilots
understand what happens to any given airframe when that condition is approached and/or reached. The very FIRST indication
of that condition is bothering to look at - you guessed it - AIRSPEED. The second indication is an audible expression of a
four letter word. This is generally followed by airframe buffet - unless a stall warning such as I have is
installed. Dynamic stall testing forms a part of your test function. Obviously stall testing is a basic flight
test function. You can and we will argue 'til hell freezes over the benefits of continued stalling in your aircraft for the hell of
it. If you want an aeroplane just to go out and stall it for fun - get a Cessna. Lancairs are designed to operate at the
other end of the speed spectrum - and that's FUN. As for airframe icing, I assume you mean you haven't encountered icing
on any aircraft you have flown when actually in cloud. However, you will need to have a clear understanding that if you choose to
fly IMC there remains the distinct possibility you will encounter it, and all YOUR stall testing becomes meaningless as the stall
characteristics of your airframe will change dramatically without you having any knowledge of what the stall point is in any given
condition of icing. If turbulence is associated with it you will slow while your stall speed will increase and you have no idea
where the coffin corner meets. Back to basics - in your stall testing, observe and record and KNOW the stall
speeds in all configurations, commit them to memory, and NEVER forget them Then fly your aeroplane for the purpose for which it was
designed. Cheers mate Dom Crain VH-CZJ
[The idea that the first indication of an impending stall comes
from airspeed is basically flawed. It's why naval aviators fly AOA during the approach. You can stall a wing at almost any airspeed, but
that wing will always stall at its one and only critical angle of attack. This means there are innumerable stalling speeds, but still only
one critical angle at which the wing will stall. Just because the airplane won't stall on base at 110 knots (for example) doesn't mean
that it won't stall at that very same airspeed when you try to tighten the turn to final and maybe double the wing loading due to the bank angle...
unless you get the nose down to widen the spread between where the critical angle was when straight and level and where it is in that 45+ degree bank,
you can bet pretty good money that the likelihood of stalling the bottom wing has gone up considerably and the possibility of finding oneself upside
down 400 ft AGL has increased dramatically... that very scenario has killed more than a few pilots, and they didn't even have to be flying a
Lancair. Another example is the high-speed pass down the runway with the sudden pullup at the end... even at 150-160 knots, you make that
pullup intense enough and the airspeed indicator will still be ticking its way down its scale long after the wing has stalled due to excessive loading
from the abrupt change in AOA (which indication is instantaneous, BTW). Airspeed remains a pretty good secondary indicator of a potential stall
condition, but only if considered in concert with all the other factors that affect wing loading. Unfortunately our bitty brains can't possibly
evaluate all the factors that affect that loading frrom moment to moment, but understanding and using an indication of AOA eliminates the need to do
so. Ain't technology grand... Just my $0.02. <Marv> ]
From: Lancair Mailing List
[mailto:lml@lancaironline.net] On Behalf Of Bill Bradburry Sent: Saturday, 10 October 2009 7:26 AM To:
lml@lancaironline.net Subject: [LML] Re: FAA RESCINDS INFO LETTER It seems to me that we have all been
scared to death by the admonishments to never stall these planes. As a result, nobody does any stall testing
or training. We will die if we stall the plane! Only do stalls above 10000 feet because you will not be able
to recover prior to impact! If this stuff is true, then it is not a judgement or training issue. A plane that
is too dangerous to stall is too dangerous to fly. A pilot needs to be able to recognize an impending stall in any plane he is
flying. If we are scared to stall these Lancairs, we will eventually stall close to the ground and become a "training
issue". I am not yet flying my Legacy, but you can be damn well certain that stalls will be part of the second
flight! The first flight will be one circuit, land, get out and kiss the ground! The other problem I think is
flight into ice. There have been several planes that have suddenly fallen out of the sky. I suspect that is
ice. I don't have thousands of hours, but so far, I have never encountered ice in any plane I have ever
flown. I don't plan to change that with my Legacy. Bill B
|