X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 09 Jan 2013 06:56:50 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTP id 6001723 for lml@lancaironline.net; Tue, 08 Jan 2013 17:33:05 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.122; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: X-Authority-Analysis: v=2.0 cv=YruNtvkX c=1 sm=0 a=MHZY6FYWMEQOp7S43i2QIw==:17 a=3Zlka_XeuxsA:10 a=ttCsPuSJ-FAA:10 a=rTjvlri0AAAA:8 a=LP9fVqJXshEA:10 a=Ia-xEzejAAAA:8 a=mCSqThwqAAAA:8 a=fLuM78UsAAAA:8 a=pGLkceISAAAA:8 a=jjqUt_clAAAA:8 a=l-kilXra_NbyJECnMZIA:9 a=wPNLvfGTeEIA:10 a=UFtNBcj8PC4A:10 a=-ZBvsNeBbbMA:10 a=CVU0O5Kb7MsA:10 a=EzXvWhQp4_cA:10 a=3jk_M6PjnjYA:10 a=MSl-tDqOz04A:10 a=mzyGO9zzx7f2GMEDX2QA:9 a=_W_S_7VecoQA:10 a=rnYgdqcAs4AA:10 a=ZV1GQB0bwyey_MSO:21 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:2736] helo=lobo) by hrndva-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 50/15-23502-E7E9CE05; Tue, 08 Jan 2013 22:32:30 +0000 X-Original-Message-ID: <726C736DF79148A3A1F911135CB96E7A@lobo> From: "Wolfgang" X-Original-To: Subject: Fw: [LML] Re: Stalls & Spins X-Original-Date: Tue, 8 Jan 2013 17:32:29 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0207_01CDEDC6.2235C870" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 This is a multi-part message in MIME format. ------=_NextPart_000_0207_01CDEDC6.2235C870 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stall strips are good, they widen the stall warning zone. Cuffs are good, they do more of the same. But once you are in a spin in spite of those devices, what is there to = help you recover ? . . . I'm thinking more tail moment and further forward CG . . . neither = of which improve efficiency but do help stability. . . . but that needs to be built in, it's not something that can be = glued on after the fact. . . . . . . the "kangaroo tail" might be an exception. Wolfgang ----- Original Message -----=20 From: John Smith=20 To: lml@lancaironline.net=20 Sent: Tuesday, January 08, 2013 6:20 AM Subject: Re: [LML] Re: Stalls & Spins From my perspective, the key phrase is spin resistance. Having researched the NASA material and having also seen the Lancair = videos of actual flight testing, rightly or wrongly, I installed the = wing cuffs to the Legacy on the basis that they seemed to offer the = opportunity to make it harder to get into trouble, but accepting that if = pushed too far into a spin, then the aircraft may or may not be = recoverable. So, if one accepts the view of many which is that "as was", = the aircraft was not spin recoverable, there would only appear to be = upside from installing the cuffs. The flaw is, of course, that if indeed = the Legacy is spin recoverable without wing cuffs, then the addition of = the wing cuffs may preclude spin recovery! Unless someone goes to the trouble of spin testing the Legacy, or any = other type fitted with cuffs, one will never know whether spin = recoveries are possible under what flight and loading circumstances and, = of course, with or without wing cuffs. Meanwhile, per my prior post on this, all I can say is that the albeit = very limited flight testing (straight and level, and continuous 30deg = AoB turns) in my Legacy fitted with the cuffs shows that there is plenty = of warning of the impending stall - stall strips give the first "gentle" = warning", followed by the more severe intermittent "shuddering" as the = centre section drops in and out of the stall (whilst the outboard = sections are still flying). I'm happy to talk to anyone if they are interested to talk about this = more.. numbers below, but please note time is UTC + 8!! Regards, John John N G Smith Tel / fax: +61-8-9385-8891 Mobile: +61-409-372-975 Email: john@jjts.net.au From: Reply-To: Lancair Mailing List Date: Tuesday, 8 January 2013 2:25 AM To: Subject: [LML] Re: Stalls & Spins Posted for "Peter Field" : 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. =20 Best regards,=20 Pete Field (LNC2) USNTPS graduate & spin recovery instructor -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html ------=_NextPart_000_0207_01CDEDC6.2235C870 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stall strips are good, they widen the = stall warning=20 zone.
Cuffs are good, they do more of the=20 same.
But once you are in a spin in spite of = those=20 devices, what is there to help you recover ?
. . . I'm thinking more tail moment and = further=20 forward CG . . . neither of which improve efficiency but do help=20 stability.
. . . but that needs to be built in, = it's not=20 something that can be glued on after the fact.
. . . . . . the "kangaroo tail" might = be an=20 exception.
 
Wolfgang
 
----- Original Message -----=20
From: John Smith =
Sent: Tuesday, January 08, 2013 6:20 AM
Subject: Re: [LML] Re: Stalls & Spins

From my perspective, the key phrase is spin = resistance.

Having researched the NASA material and having also seen the = Lancair videos=20 of actual flight testing, rightly or wrongly, I installed the wing cuffs = to the=20 Legacy on the basis that they seemed to offer the opportunity to make it = harder=20 to get into trouble, but accepting that if pushed too far into a spin, = then the=20 aircraft may or may not be recoverable. So, if one accepts the = view of=20 many which is that "as was", the aircraft was not spin recoverable, = there would=20 only appear to be upside from installing the cuffs. The flaw is, of = course, that=20 if indeed the Legacy is spin recoverable without wing cuffs, then the = addition=20 of the wing cuffs may preclude spin recovery!

Unless someone goes to the trouble of spin testing the Legacy, or = any other=20 type fitted with cuffs, one will never know whether spin recoveries are = possible=20 under what flight and loading circumstances and, of course, with or = without wing=20 cuffs.

Meanwhile, per my prior post on this, all I can say is that the = albeit very=20 limited flight testing (straight and level, and continuous 30deg AoB = turns) in=20 my Legacy fitted with the cuffs shows that there is plenty of warning of = the=20 impending stall =96 stall strips give the first "gentle" warning", = followed by the=20 more severe intermittent "shuddering" as the centre section drops in and = out of=20 the stall (whilst the outboard sections are still flying).

I'm happy to talk to anyone if they are interested to talk about = this=20 more=85. numbers below, but please note time is UTC + 8!!


Regards,

John


John N G Smith
Tel / fax:=20    +61-8-9385-8891
Mobile:=20      +61-409-372-975
Email:=20         john@jjts.net.au

<= /FONT>

From: <marv@lancair.net>
Reply-To: Lancair Mailing List <lml@lancaironline.net>
Date: Tuesday, 8 January 2013 2:25 = AM
To: <lml>
Subject: [LML] Re: Stalls & = Spins



Posted for "Peter Field" <pfield.avn@gmail.com>:
Dear=20 Lancair Drivers:



I've been following the discussion on = stalls=20 and spins and I want to add
some additional factual information = purely for=20 your personal consumption and
reflection.  Attached are = excerpts=20 from 10 different 1980-90 NASA flight
test final reports on a = series of GA=20 airplanes in which NASA evaluated the
use of cuffs on leading edges = to=20 improve the behavior of the test airplane
approaching the=20 stall.  For various reasons the cuffs improved = lateral
control=20 entering the stall, but had the adverse effect of destabilizing=20 the
aircraft once a fully developed spin was=20 achieved.  Essentially, stall
behavior was improved at = the=20 sacrifice of spin recovery.  Cuffs on wing
leading edges = are an=20 add on design fix, the more elegant solution is
"washout," where = the wing=20 is twisted so the outer portions of the wing
always operate at a = lower=20 angle of attack.



To my knowledge, Lancair has never = subjected=20 any of their aircraft to a
fully developed spin matrix complete = with=20 appropriate instrumentation and a
spin recovery = chute.  There is=20 no FAA requirement for them to do so - it's
an Experimental = Category=20 airplane.  Early on they may have lightly touched
on such = testing; but I have never seen any documentation on a = fully
completed spin=20 matrix, which would involve at least 160 spins at various
cg's and = lateral=20 loadings.  In my opinion, it would be highly risky to = fool
around=20 much beyond the stall in any Lancair - there is no documentation=20 that
indicates any of these airplanes can always be recovered from = a one=20 turn
incipient phase spin or any fully developed = spin.  Being=20 good at spin
recovery isn't so much a matter of how skillful a = pilot you=20 are, it's a
matter of how many spins you've experienced in = airplanes known=20 to be
recoverable.  Being familiar with the stall = characteristics=20 of your own
airplane should be a matter of personal=20 preference.  



Best regards,

Pete = Field=20 (LNC2)

USNTPS graduate & spin recovery=20 instructor



-- For archives and unsub http://mail= .lancaironline.net:81/lists/lml/List.html=20 ------=_NextPart_000_0207_01CDEDC6.2235C870--