X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 16 Jul 2010 12:28:21 -0400 Message-ID: X-Original-Return-Path: Received: from snt0-omc3-s1.snt0.hotmail.com ([65.55.90.140] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4395466 for lml@lancaironline.net; Fri, 16 Jul 2010 10:49:07 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.90.140; envelope-from=gary21sn@hotmail.com Received: from SNT112-DS20 ([65.55.90.135]) by snt0-omc3-s1.snt0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 16 Jul 2010 07:47:13 -0700 X-Originating-IP: [24.216.229.86] X-Originating-Email: [gary21sn@hotmail.com] X-Original-Message-ID: X-Original-Return-Path: gary21sn@hotmail.com From: "Gary Edwards" X-Original-To: "Lancair Mailing List" References: Subject: Re: Small tail, MK II tail, CG range X-Original-Date: Fri, 16 Jul 2010 07:47:07 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_018B_01CB24BB.189F79E0" X-Priority: 3 X-MSMail-Priority: Normal In-Reply-To: X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V10.00.0070.1500 Seal-Send-Time: Fri, 16 Jul 2010 07:47:07 -0700 X-OriginalArrivalTime: 16 Jul 2010 14:47:13.0795 (UTC) FILETIME=[C7357D30:01CB24F5] This is a multi-part message in MIME format. ------=_NextPart_000_018B_01CB24BB.189F79E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable All the more reason to have an AOA indicator. Gary Edwards The CAFE report on the small tail 320 mentions the very low "stick force = gradient" as=20 a problem. The stick force was found to be almost neutral at the rear CG = limit.=20 As I understand it the gradient is much higher in the Legacy,=20 and about halfway in between on the large tail 360. =20 I seem to remember Greg Heinze of HPAT telling me the SFG numbers for the three models=20 on the phone...but I have since forgotten the values he quoted. I understand that a low gradient is a problem since the pilot has no = feel that he is pulling hard just before stall. Perhaps worse, in the stall, just = releasing the stick pressure does not unstall the A/C. Rather, the pilot must calmly place the stick = forward....preferably without inducing PIO, despite the adrenaline load. I don't know much aerodynamics but I am familiar with second order = differential equations. Having tuned servo systems, I would be wary of nuetral stability. = Wouldn't INstability be right around the corner? Am I right about this? The recent long debate on CG ranges has not so far discussed this. What = is the role of stick force gradient in this debate? --=20 Jeff Peterson ------=_NextPart_000_018B_01CB24BB.189F79E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
All the more reason to have an AOA indicator.
 
Gary Edwards
 
 
The CAFE report on the small tail 320 mentions the very low "stick = force=20 gradient" as
a problem. The stick force was found to be almost = neutral at=20 the rear CG limit.
As I understand it the gradient is much higher in = the=20 Legacy,
and about halfway in between on the large tail 360.  =

I=20 seem to remember
Greg Heinze of HPAT telling me the SFG numbers for = the three=20 models
on the phone...but I have since forgotten the
values he=20 quoted.

I understand that a low gradient = is a=20 problem since the pilot has no feel that
he is pulling hard just = before=20 stall. Perhaps worse, in the stall, just releasing the stick pressure = does=20 not
unstall the A/C.  Rather, the pilot must calmly place the = stick=20 forward....preferably without inducing PIO, despite
the adrenaline=20 load.

I don't know much aerodynamics but I am = familiar=20 with second order differential equations.
Having tuned servo systems, = I would=20 be wary of nuetral stability.  Wouldn't INstability be right around = the=20 corner?
Am I right about this?

The recent long debate on CG = ranges has=20 not so far discussed this. What is
the role of stick force gradient = in this=20 debate?

--
Jeff = Peterson

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