Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Wed, 26 Jan 2005 20:21:07 -0500 Message-ID: X-Original-Return-Path: Received: from lakermmtao07.cox.net ([68.230.240.32] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 623988 for lml@lancaironline.net; Wed, 26 Jan 2005 20:12:57 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.240.32; envelope-from=danobrien@cox.net Received: from Dan.cox.net ([68.100.82.159]) by lakermmtao07.cox.net (InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP id <20050127011226.PHPV20686.lakermmtao07.cox.net@Dan.cox.net> for ; Wed, 26 Jan 2005 20:12:26 -0500 X-Original-Message-Id: <6.2.0.14.0.20050126183930.01e31c40@127.0.0.1> X-Mailer: QUALCOMM Windows Eudora Version 6.2.0.14 X-Original-Date: Wed, 26 Jan 2005 20:12:24 -0500 X-Original-To: lml@lancaironline.net From: Dan O'Brien Subject: Lancair stalls for mere mortals Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=====================_10724000==.ALT" --=====================_10724000==.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed With all this discussion about the stall characteristics of Lancair's high laminar flow wings, I fear that mere mortals like myself (as opposed to some of the real engineers talking on the list) might miss a basic lesson in all of this. The lesson is that THERE IS TYPICALLY A TRADEOFF between the slow, docile, virtually idiot proof wings like the ones found on Cessna 152s (which practially self-recover from stalls when hands are removed) and the speedy, high laminar flow, wings like those on Lancairs (be it the 320/360/Legacy wings or the IV/ES wing). At least this is what I've gleaned from my own reading of various books on aircraft performance. This is not surprising. If Cessna could have had an idiot proof stall AND a high laminar flow, low drag wing, they surely would have chosen one. However, they couldn't, because it would have violated the laws of physics (although the Columbia, with its cuffs, almost disproves the point...what an engineering marvel...) In any event, it seems to me that the most important point from this discussion, made a few years ago on this list by test pilot Mike DeHate, is this: The Lancair aircraft are intolerant of pilot inattention in slow flight and particularily during stalls. I stress to all pilots that I check out that the one thing that will cause them bodily harm is cross controlling the aircraft at low speeds (stalls). The most important items in stall testing in these aircraft are to proceed with caution, start with power COMPLETELY OFF and KEEP THE BALL IN THE MIDDLE. Once you have mastered this, then proceed with testing with partial power before trying them with massive amounts of TORQUE. Remember that we are flying a wing that is not designed for slow speed characteristics like the old Clark Y airfoil in early training aricraft. Tis extremely difficult to remind oneself that their primary objective was to drain the swamp, when they are up to their ass in alligators... Get good training, then get LOTS of altitude before attempting stalls in your Lancair. For most of my experiences they fall off straight ahead with power off, and do a bit of torque roll with power on. All bets are off on Iv's with winglets, they are a special breed unto themselves, and any mis-alignment will cause unknown results. One I tested at great length demonstrated flow reversal just before the break which was predictable after a few tries. It always broke nose down and to the right, every time, but always with the ball in the middle. I took one of the Flight Craft instructors up with me in 409L after they complained that the airplane would "always" go inverted in a power off stall, we went up and I repeatedly had the airplane stall (very docile and predictable) staight ahead every time, wings level, ball in the middle. I could stall 409L and hold the stick fully aft in a fully developed stall and it did not demonstrate any tendancy to roll over on its back and play turtle. But, I kept the ball in the MIDDLE... Remember PLEASE, you are flying a high performance wing, not unlike some of the business jets out there, and they do not go out and stall them..... Fly SMART and SAFE.. Mike Sorry for quoting you without asking Mike, but I think this little lesson says an awful lot in a way that mere mortals like myself can understand. If we were all born with genes that caused us to pay attention to advice like this, our insurance rates would surely fall. --=====================_10724000==.ALT Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable With all this discussion about the stall characteristics of Lancair's high laminar flow wings, I fear that mere mortals like myself (as opposed to some of the real engineers talking on the list) might miss a basic lesson in all of this.  The lesson is that THERE IS TYPICALLY A TRADEOFF between the slow, docile, virtually idiot proof wings like the ones found on Cessna 152s (which practially self-recover from stalls when hands are removed) and the speedy, high laminar flow, wings like those on Lancairs (be it the 320/360/Legacy wings or the IV/ES wing).  At least this is what I've gleaned from my own reading of various books on aircraft performance.  This is not surprising.  If Cessna could have had an idiot proof stall AND a high laminar flow, low drag wing, they surely would have chosen one.  However, they couldn't, because it would have violated the laws of physics (although the Columbia, with its cuffs, almost disproves the point...what an engineering marvel...)  In any event, it seems to me that the most important point from this discussion, made a few years ago on this list by test pilot Mike DeHate, is this:

The Lancair aircraft are intolerant of pilot inattention in slow flight and
particularily during stalls. I stress to all pilots that I check out that
the one thing that will cause them bodily harm is cross controlling the
aircraft at low speeds (stalls). The most important items in stall testing
in these aircraft are to proceed with caution, start with power COMPLETELY
OFF and KEEP THE BALL IN THE MIDDLE. Once you have mastered this, then
proceed with testing with partial power before trying them with massive
amounts of TORQUE. Remember that we are flying a wing that is not designed
for slow speed characteristics like the old Clark Y airfoil in early training
aricraft.

Tis extremely difficult to remind oneself that their primary objective was to
drain the swamp, when they are up to their ass in alligators... Get good
training, then get LOTS of altitude before attempting stalls in your Lancair.
For most of my experiences they fall off straight ahead with power off, and
do a bit of torque roll with power on. All bets are off on Iv's with
winglets, they are a special breed unto themselves, and any mis-alignment
will cause unknown results. One I tested at great length demonstrated flow
reversal just before the break which was predictable after a few tries. It
always broke nose down and to the right, every time, but always with the ball
in the middle.
I took one of the Flight Craft instructors up with me in 409L after they
complained that the airplane would "always" go inverted in a power off stall,
we went up and I repeatedly had the airplane stall (very docile and
predictable) staight ahead every time, wings level, ball in the middle. I
could stall 409L and hold the stick fully aft in a fully developed stall and
it did not demonstrate any tendancy to roll over on its back and play turtle.
But, I kept the ball in the MIDDLE...

Remember PLEASE, you are flying a high performance wing, not unlike some of
the business jets out there, and they do not go out and stall them.....

Fly SMART and SAFE..
Mike=20
Sorry for quoting you without asking Mike, but I think this little lesson says an awful lot in a way that mere mortals like myself can understand.  If we were all born with genes that caused us to pay attention to advice like this, our insurance rates would surely fall. --=====================_10724000==.ALT--