X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 04 Aug 2008 13:41:51 -0400 Message-ID: X-Original-Return-Path: Received: from mta10.adelphia.net ([68.168.78.202] verified) by logan.com (CommuniGate Pro SMTP 5.2.6) with ESMTP id 3060367 for lml@lancaironline.net; Mon, 04 Aug 2008 08:18:37 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.202; envelope-from=glcasey@adelphia.net Received: from [75.83.27.99] by mta10.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20080804122149.DXGU20419.mta10.adelphia.net@[75.83.27.99]> for ; Mon, 4 Aug 2008 08:21:49 -0400 Mime-Version: 1.0 (Apple Message framework v753) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-14--973092729 X-Original-Message-Id: <3FC20024-7924-4B2B-8AB7-630A218B1799@adelphia.net> From: Gary Casey Subject: Re: Lancair IV Strakes X-Original-Date: Mon, 4 Aug 2008 05:17:55 -0700 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.753) --Apple-Mail-14--973092729 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed John, No, mine did not have the extended leading edge mod. That is also perhaps a good thing to have, but I didn't install it. It increases the chord and sweep angle of the vertical stab, but increasing the chord doesn't proportionally increase the effectiveness, especially at low angles of attack. Increasing the sweep angle may delay or prevent a "stall" of the vertical stab, but it makes it less effective at low angles of attack, which are required if the objective is increased stability. Extending the vertical forward also increases, not decreases the "torque effect" - the turning tendency due to the swirling prop wash. Adding a fin below the fuselage improves all those characteristics. Another bit of speculation (as I am not an aerodynamics expert) is that a blade-type delta wing will have a high lift at low angles of attack and will not have an abrupt stall characteristic, although at a drag penalty. I don't know if having two strakes in a V configuration adds much in the way of pitch stability, as the ES horizontal stab is already large. Perhaps a single vertical blade-type strake would do just as well with less drag, I don't know. Gary On Aug 4, 2008, at 3:01 AM, Lancair Mailing List wrote: > > > From: "John McMahon" > Date: August 3, 2008 5:46:39 PM PDT > To: lml@lancaironline.net > Subject: Re: [LML] Re: Lancair IV Strakes > > > Gary - Do you have the optional fairing Lancair offered for the > leading edge of the vertical stabilizer? I seem to remember that > Kirk H. had added one to his ES. What was it supposed to do? Was > it only for the ES or also for the IVs? Has anybody got any input > as to the effectiveness of that fairing and how it effects or > compliments the effect of the ventral strakes? > > On Sun, Aug 3, 2008 at 11:48 AM, Gary Casey > wrote: > I performed some back-to-back tests on my ES after getting some > feedback from a professional test pilot. He said that the strakes > (as far as I know there is only one commercial source for these at > the moment) were "necessary" on the IVPT, "important" on the IVP > and "made an improvement" on the ES. > --Apple-Mail-14--973092729 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 John,
No, mine did not have the extended leading edge mod. =A0That = is also perhaps a good thing to have, but I didn't install it. =A0It = increases the chord and sweep angle of the vertical stab, but increasing = the chord doesn't proportionally increase the effectiveness, especially = at low angles of attack. =A0Increasing the sweep angle may delay or = prevent a "stall" of the vertical stab, but it makes it less effective = at low angles of attack, which are required if the objective is = increased stability. =A0Extending the vertical forward also increases, = not decreases the "torque effect" - the turning tendency due to the = swirling prop wash. =A0Adding a fin below the fuselage improves all = those characteristics. =A0Another bit of speculation (as I am not an = aerodynamics expert) is that a blade-type delta wing will have a high = lift at low angles of attack and will not have an abrupt stall = characteristic, although at a drag penalty. =A0I don't know if having = two strakes in a V configuration adds much in the way of pitch = stability, as the ES horizontal stab is already large. =A0Perhaps a = single vertical blade-type strake would do just as well with less drag, = I don't know.
Gary =A0 =A0
On Aug 4, 2008, at 3:01 AM, = Lancair Mailing List wrote:
From: "John McMahon" <blackoaks@gmail.com>
<= div style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 40px; text-indent: -40px; ">Date: August 3, 2008 5:46:39 PM = PDT
To: lml@lancaironline.net
Subject: Re: [LML] Re: Lancair IV = Strakes

=
Gary - Do you have the optional fairing Lancair offered = for the leading edge of the vertical stabilizer?=A0 I seem to remember = that Kirk H. had added one to his ES.=A0=A0 What was it supposed to do?=A0= Was it only for the ES or also for the IVs?=A0 Has anybody got any = input as to the effectiveness of that fairing and how it effects or = compliments the effect of the ventral strakes?

On Sun, Aug 3, 2008 at 11:48 AM, Gary Casey <glcasey@adelphia.net> = wrote:
I performed some back-to-back tests on my ES = after getting some feedback from a professional test pilot. =A0He said = that the strakes(as far as I know there is only one commercial source = for these at the moment) were "necessary" on the IVPT, "important" on = the IVP and "made an improvement" on the ES.
=


= --Apple-Mail-14--973092729--