X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 17 Jul 2011 10:11:09 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da03.mx.aol.com ([205.188.105.145] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5053720 for lml@lancaironline.net; Sat, 16 Jul 2011 08:47:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.145; envelope-from=MikeEasley@aol.com Received: from mtaomg-ma01.r1000.mx.aol.com (mtaomg-ma01.r1000.mx.aol.com [172.29.41.8]) by imr-da03.mx.aol.com (8.14.1/8.14.1) with ESMTP id p6GCl5mH024806 for ; Sat, 16 Jul 2011 08:47:05 -0400 Received: from core-mke002b.r1000.mail.aol.com (core-mke002.r1000.mail.aol.com [172.29.98.197]) by mtaomg-ma01.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 25EC9E000088 for ; Sat, 16 Jul 2011 08:47:05 -0400 (EDT) From: MikeEasley@aol.com X-Original-Message-ID: <10b75.77facf5d.3b52e248@aol.com> X-Original-Date: Sat, 16 Jul 2011 08:47:05 -0400 (EDT) Subject: Re: [LML] Re: another Lancair X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_10b75.77facf5d.3b52e248_boundary" X-Mailer: AOL 9.6 sub 5003 X-AOL-IP: 75.71.55.189 X-Originating-IP: [75.71.55.189] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:297184544:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d29084e2188496ced --part1_10b75.77facf5d.3b52e248_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Gliding your airplane to the ground and trying to hit your aim point about 1/3 down the runway is a very unnatural looking exercise, especially in an airplane with high wing loading and a high stall speed. In my ES, it's somewhat of a "non-event" with the big wings and no gear to deal with. I still find it a challenge with my average pilot skills and only about 300 hours in my ES to have it feel comfortable. Combine that with the stress and IQ drop of a real emergency and I figure I need to be really good at it during training to be even close to competent in a real engine out, dead stick landing. During my training, I'm glad I have an ES, not a IV! The FAA in its infinite wisdom, set the stall speed for single engine certified aircraft at a slow enough speed for average pilots to put the plane down off-airport and have that event be survivable. (You don't often hear the words FAA and wisdom in the same sentence) I'm sure they figured that single engine aircraft are more likely to lose all power compared to twins. That's a tradeoff they felt was wise for safety, even though it sacrifices some significant performance in cruise speed. Designs have gotten better over the years and now you can have a relatively fast airplane and still have a slow stall speed. I believe the ES and the IV have the same wing design, but the ES is 40% larger. They use a very high lift airfoil at the root and a more benign airfoil at the tip. The root airfoil has a very quick change from high lift to stall with a small change angle of attack. The airfoil transitions linearly from the root to the tip with 2 degrees of washout on the ES. (not totally sure about the washout on the IV). The theory is you would never put the inboard airfoil into a stall because the tips would stall first. As the stall moved inward the whole wing would stall before the nasty stall characteristics of the root ever came into play. So in a typical training stall, Lancairs are pretty manageable, but in an emergency where you might stretch a glide, not drop the nose quickly enough, or attempt a 180 back to the runway, a deep stall could occur and that's a different story. The IV and the rest of the Lancair fleet are examples of aircraft that lean more towards performance by sacrificing the stall speed and stall characteristics in exchange for cruise speed. Less wing area, choice of airfoil, washout, empennage area, etc. can really increase the performance in cruise, but it comes at a price on the slow end of the performance envelope. Too many pilots transitioning from single engine certified aircraft to a Lancair don't take that difference seriously enough. Mike Easley Colorado Springs --part1_10b75.77facf5d.3b52e248_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Gliding your airplane to the ground and trying to hit your aim point a= bout=20 1/3 down the runway is a very unnatural looking exercise, especially in an= =20 airplane with high wing loading and a high stall speed.  In my ES, it'= s=20 somewhat of a "non-event" with the big wings and no gear to deal with. = ; I=20 still find it a challenge with my average pilot skills and only about 300 h= ours=20 in my ES to have it feel comfortable.  Combine that with the stress an= d IQ=20 drop of a real emergency and I figure I need to be really good at it during= =20 training to be even close to competent in a real engine out, dead stick lan= ding.=20 During my training, I'm glad I have an ES, not a IV!
 
The FAA in its infinite wisdom, set the stall speed for single engine= =20 certified aircraft at a slow enough speed for average pilots to put the pla= ne=20 down off-airport and have that event be survivable. (You don't often hear t= he=20 words FAA and wisdom in the same sentence) I'm sure they figured that singl= e=20 engine aircraft are more likely to lose all power compared to twins. = =20 That's a tradeoff they felt was wise for safety, even though it sacrifices = some=20 significant performance in cruise speed.  Designs have gotten better o= ver=20 the years and now you can have a relatively fast airplane and still have a = slow=20 stall speed.
 
I believe the ES and the IV have the same wing design, but the ES is 4= 0%=20 larger.  They use a very high lift airfoil at the root and a more beni= gn=20 airfoil at the tip.  The root airfoil has a very quick change from hig= h=20 lift to stall with a small change angle of attack. The airfoil transitions= =20 linearly from the root to the tip with 2 degrees of washout on the ES.= (not=20 totally sure about the washout on the IV). The theory is you would never pu= t the=20 inboard airfoil into a stall because the tips would stall first.  As t= he=20 stall moved inward the whole wing would stall before the nasty stall=20 characteristics of the root ever came into play. So in a typical training s= tall,=20 Lancairs are pretty manageable, but in an emergency where you might stretch= a=20 glide, not drop the nose quickly enough, or attempt a 180 back to the= =20 runway, a deep stall could occur and that's a different story.
 
The IV and the rest of the Lancair fleet are examples of air= craft=20 that lean more towards performance by sacrificing the stall speed and = stall=20 characteristics in exchange for cruise speed.  Less wing area, choice = of=20 airfoil, washout, empennage area, etc. can really increase the=20 performance in cruise, but it comes at a price on the slow end of the= =20 performance envelope.  Too many pilots transitioning from single engin= e=20 certified aircraft to a Lancair don't take that difference seriously=20 enough.
 
Mike Easley
Colorado Springs
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