X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 27 Jan 2010 18:52:48 -0500 Message-ID: X-Original-Return-Path: Received: from web36906.mail.mud.yahoo.com ([209.191.85.74] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with SMTP id 4100862 for lml@lancaironline.net; Wed, 27 Jan 2010 13:56:48 -0500 Received-SPF: none receiver=logan.com; client-ip=209.191.85.74; envelope-from=chris_zavatson@yahoo.com Received: (qmail 51098 invoked by uid 60001); 27 Jan 2010 18:56:10 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=DU7retGQFdpXSwzHFoL9g9vqeGj44rDkADNq2cfYFp/3ysWoW2Qj/2jHr34hGucUv8zIwNS/ZMJqSH3qyd3uR/abLgHeI84ZG+IZ2pAdPXZwxVwXdmka8Kun5yJGdccArIRcKoC2A2giNGSkaXJdX9HsMCQMZnsjDwd/xE1Ztd0=; X-Original-Message-ID: <829054.49445.qm@web36906.mail.mud.yahoo.com> X-YMail-OSG: MPAEJXAVM1lSwSbyzy4JEbfDEIcp9M4TLYe5uHBEAJdnKUiMUT_B_6Ir1o8iVmTzOeZgC4AZYtV4BSSDW8HfP9sO5hWhvdNN8FkwNUnLKo7cc58uQW1iR7OV5klPgMgqyqCYzjFrlRu4ImdHmxP.mZCGHlSOPPyVb.mJIAjpLMHVpStU_byU69ES3RaOgFjbxV58R74ZPYVP1eEZqEw7_HZMlXuQJ0jYJ0VH2SUicyB.Y6CF2N3d0yhVR61zT7gJGd6eYTSMKPRWUPITp_kSV.qC0t5jS8HlsnOzF05CkyjjbiYXmRv6yd75hskHj3LADTEhE.HOY4EqUHSR3ju0IiPzZ_Snzf42YrF2oj1PD2ErJGKAoJvKCyYcH273i_NOLxHJsW.ial73JwrU5PRob21Nv4EWjhG9zQlhQ5JcaNI5G2tM88nxxA0hwQ-- Received: from [149.32.224.33] by web36906.mail.mud.yahoo.com via HTTP; Wed, 27 Jan 2010 10:56:10 PST X-Mailer: YahooMailRC/272.7 YahooMailWebService/0.8.100.260964 References: X-Original-Date: Wed, 27 Jan 2010 10:56:10 -0800 (PST) From: Chris Zavatson Subject: Re: [LML] Re: Airspeed sensing switch /Auto gear extension / Engine out gear down Issue! X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-731962252-1264618570=:49445" --0-731962252-1264618570=:49445 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Terrence,=0AAOA will compensate for weight very nicely.=A0 It doesn't know,= however, what descent rate is being flown and how much energy is needed to= arrest that sink.=A0 The energy needed goes up as a squared function of th= e vertical speed.=A0 In the 360, I span descent rates from 500 to 2,000 fpm= on final (ILS to short approaches).=A0 The energy=A0thus varies by a facto= r=A0~16.=A0 It is the higher end of the scale where one can get=A0into trou= ble.=A0=A0=0AThe sink rate introduces a time element that the AOA indicator= can't factor in.=A0 Here is a thought experiment to illustrate the point.= =A0=A0In the flare you bump your AOA from your mark to=A0just under stall.= =A0 This will generate a new, higher quantity of lift that will immediately= begin to decay as the new added drag slows the plane.=A0=A0Now, the=A0high= er your descent rate was, the longer that new, higher, but tapering lift mu= st act on the plane to stop the sink (F=3Dma).=A0=A0The question becomes:= =A0 Do you have enough time before you run out of speed?=A0 If you do, then= you stop the sink and all is good.=A0 If not, you smack the runway at a hi= gh AOA but still descending.=0A=0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91= CZ.com=0A=0A=0A=0A=0A________________________________=0AFrom: Terrence O'Ne= ill =0ATo: lml@lancaironline.net=0ASent: Wed, January= 27, 2010 2:47:03 AM=0ASubject: [LML] Re: Airspeed sensing switch /Auto gea= r extension / Engine out gear down Issue!=0A=0AChris, =0AThis problem of ca= lculating the changing speed for different weights, etc., for keeping reser= ve energy, =A0is a good example of a problem that vanishes if you use an AO= A. =A0Mine has a mark at the AOA that leaves a Cl reserve for flare. =A0I d= on't have any idea (or care) =A0what speed I'm at during final to flare... = just keep the AOA where there's enough AOA lift left for flare.=0AAmen to n= o power, full flaps, gear down for flare. I try to get back to the power-of= f approaches my ex-WW II-pilot instructors taught me in Pprterfields ... bu= t it's difficult or frustrating when the guy ahead doesn't take his interva= l upwind, or when someone announces he's coming straight-in after I'm alrea= dy downwind.=0ATerrence N211AL L235/320=A0=0A=0A=0AOn Jan 26, 2010, at 10:1= 0 AM, Chris Zavatson wrote:=0A=0A"Gear and flaps down too early with a dead= engine will have disasterous consequences every time."=0A>=0A>"That is a d= eadly mistake. Dragging gear and flaps, you need a steep nose down attitude= to keep the airspeed at a safe speed. Unfortunately, in that regime you ca= n not flair the airplane. When you try to flair without a little power thes= e airplanes just slow down and hit the ground."=0A>=0A>"When you try to fla= ir without a little power these airplanes just slow down and hit the ground= . The situation is much worse if you are heavy. "=0A>=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=0A>Full flaps, gear down and no power should lead to a grea= ser every time.=A0 Our Lancairs have a broad range of drag and thus require= a=A0good understanding of energy management.=0A>At issue here is how=A0one= defines 'safe speed'.=A0=0A>As the approach angle steepens due to higher d= rag, so does the required speed (or energy) to round out and flair.=A0 That= higher energy is used to stop the descent and bring the vertical speed to = zero.=A0=A0=A0One can even calculate the speed required as a function of de= scent angle to bring the plane to level flight in the flare at the same fin= al speed.=A0 In general, I prefer power off, steep approaches.=A0=A0That wa= y if=A0the engine hick-ups, it is no big deal.=A0 When heavy, it takes a fe= w more knots for the same maneuver, but you can still grease=A0the landing.= =A0 It is all about energy management.=A0 One cannot stick to a fixed numbe= r on the airspeed indicator.=A0 Doing so could have you coming up short of = energy.=A0 The broad range of drag available to us on these planes is truly= an asset.=0A>=0A>Chris Zavatson=0A>N91CZ=0A>360std=0A>www.N91CZ.com=0A>=0A= >=0A>=0A=0A=0A=0A --0-731962252-1264618570=:49445 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Terrence,
=0A
AOA will compensate for weight very nicely= .  It doesn't know, however, what descent rate is being flown and how = much energy is needed to arrest that sink.  The energy needed goes up = as a squared function of the vertical speed.  In the 360, I span desce= nt rates from 500 to 2,000 fpm on final (ILS to short approaches).  Th= e energy thus varies by a factor ~16.  It is the higher end = of the scale where one can get into trouble.  
=0A
= The sink rate introduces a time element that the AOA indicator can't factor= in.  Here is a thought experiment to illustrate the point.  = ;In the flare you bump your AOA from your mark to just under stall.&nb= sp; This will generate a new, higher quantity of lift that will immediately= begin to decay as the new added drag slows the plane.  Now, the&= nbsp;higher your descent rate was, the longer that new, higher, but taperin= g lift must act on the plane to stop the sink (F=3Dma).  The ques= tion becomes:  Do you have enough time before you run out of speed?&nb= sp; If you do, then you stop the sink and all is good.  If not, you sm= ack the runway at a high AOA but still descending.
=0A
 =0A
Chris Zavatson
=0A
N91CZ
=0A
360std
=0Awww.N91CZ.com
=0A

=0A=0A
=0AFrom: Terrence O'Neill <troneill@charter.net&= gt;
To: lml@lancaironlin= e.net
Sent: Wed, January= 27, 2010 2:47:03 AM
Subject: [LML] Re: Airspeed sensing switch /Auto gear extension / Engine out g= ear down Issue!

Chris, =0A
This problem of calculat= ing the changing speed for different weights, etc., for keeping reserve ene= rgy,  is a good example of a problem that vanishes if you use an AOA. =  Mine has a mark at the AOA that leaves a Cl reserve for flare.  = I don't have any idea (or care)  what speed I'm at during final to fla= re... just keep the AOA where there's enough AOA lift left for flare.
= =0A
Amen to no power, full flaps, gear down for flare. I try to get bac= k to the power-off approaches my ex-WW II-pilot instructors taught me in Pp= rterfields ... but it's difficult or frustrating when the guy ahead doesn't= take his interval upwind, or when someone announces he's coming straight-i= n after I'm already downwind.
=0A
Terrence N211AL L235/320 =0A

=0A
=0A
On Jan 26, 2010, at 10:10 AM, Chris Zavatso= n wrote:

=0A
= =0A
=0A
=0A
"Gear and flaps down t= oo early with a dead engine will have disasterous consequences every time."=
=0A
"That is a deadly mistake. Dragging= gear and flaps, you need a steep nose down attitude to keep the airspeed a= t a safe speed. Unfortunately, in that regime you can not flair the airplan= e. When you try to flair without a little power these airplanes just slow d= own and hit the ground."
=0A
 
=0A=
"When you try to flair without a little power th= ese airplanes just slow down and hit the ground. The situation is much wors= e if you are heavy. "
=0A
=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D
=0A
Full flaps, gear down= and no power should lead to a greaser every time.  Our Lancairs have = a broad range of drag and thus require a good understanding of energy = management.
=0A
At issue here is how on= e defines 'safe speed'. 
=0A
As the app= roach angle steepens due to higher drag, so does the required speed (or ene= rgy) to round out and flair.  That higher energy is used to stop the d= escent and bring the vertical speed to zero.   One can even = calculate the speed required as a function of descent angle to bring the pl= ane to level flight in the flare at the same final speed.  In general,= I prefer power off, steep approaches.  That way if the engi= ne hick-ups, it is no big deal.  When heavy, it takes a few more knots= for the same maneuver, but you can still grease the landing.  It= is all about energy management.  One cannot stick to a fixed number o= n the airspeed indicator.  Doing so could have you coming up short of = energy.  The broad range of drag available to us on these planes is tr= uly an asset.
=0A
 
=0A
Chris Zavatson
=0A
N91CZ=0A
360std
=0A




=0A=0A=0A=0A = --0-731962252-1264618570=:49445--