X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 21 Dec 2009 06:18:55 -0500 Message-ID: X-Original-Return-Path: Received: from smtp1-g21.free.fr ([212.27.42.1] verified) by logan.com (CommuniGate Pro SMTP 5.3c4) with ESMTP id 4033243 for lml@lancaironline.net; Mon, 21 Dec 2009 02:50:20 -0500 Received-SPF: none receiver=logan.com; client-ip=212.27.42.1; envelope-from=alainoireaux@free.fr Received: from smtp1-g21.free.fr (localhost [127.0.0.1]) by smtp1-g21.free.fr (Postfix) with ESMTP id D49599400C8 for ; Mon, 21 Dec 2009 08:49:41 +0100 (CET) Received: from [192.168.0.10] (lam60-1-82-233-128-177.fbx.proxad.net [82.233.128.177]) by smtp1-g21.free.fr (Postfix) with ESMTP id D9348940014 for ; Mon, 21 Dec 2009 08:49:38 +0100 (CET) X-Original-Message-ID: <4B2F2873.4020506@free.fr> X-Original-Date: Mon, 21 Dec 2009 08:49:07 +0100 From: Alain NOIREAUX User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] Va References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------010606090100060907080305" This is a multi-part message in MIME format. --------------010606090100060907080305 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit I do reduce my speed to Va , in moderate to severe turbulence , not in light turbulence . Alain Noireaux L 320 F-PSDV Sky2high@aol.com a écrit : > Topic changed so I changed the subject. > > Generally, a Lancair 320 equipped with a 360 can easily push "cruise" > into the yellow arc (> 180 KIAS) and stay there all day.. But to the > point, I want to know how many have slowed their 320/360 to Va (143 > KIAS) in turbulence? Come on, raise your hands if you do that.... OK, > I only see 2 or 3 hands. > > I have difficulty slowing down to 143 KIAS and I would use a few > degrees of flaps to keep the nose down. I have slowed in nasty > turbulence - to about 160 KIAS from 180. For me, nasty is my guess > of moderate turbulence as evaluated in a 320. > > So, for those of us frequently flying in the yellow arc and not > slowing to Va in turbulence, how are we different than Stuart's > controlled expansion of the flight envelope beyond Vne? OK, that is > from a structural aspect, not control surface flutter. > > Well, let's see. Below Va is the speed at which no combination of > maneuver and gust load (<30 fps) at max gross weight cannot produce a > positive air load that would create damage. > > Va can be computed as Vs * SQRT(Limit load factor) > > As originally set up, the stated limit was 4.5 Gs at 1685 pounds. And > let's say we use 68 KIAS as cruise configuration Vs (stall speed). > > Then Va = 68* SQRT (4.5) = 68* 2.1 = 142.8 KIAS > > > Grayhawk > > > > In a message dated 12/20/2009 6:35:13 P.M. Central Standard Time, > sltroutman@hotmail.com writes: > > It would seem to me that the maneuvering speed would be more of a > concern than VNE but no mention of it yet. I bet that most have > exceeded Va and never thought twice about it ?? > > ----- Original Message ----- > *From:* farnsworth > *To:* lml@lancaironline.net > *Sent:* Sunday, December 20, 2009 6:51 AM > *Subject:* [LML] Re: Tone on list > > > > > > > “On August 09, 2005 N750F, a Lancair IV-P disintegrated in > flight in a dive at Mach 0.62. It is not in your list as it > happened in Canada (Transport Canada Report A05W0160). > > In June of 2003 N29ME, a Lancair IV-P, disintegrated in flight > after exceeding 253KTAS (274KIAS). (NTSB Report ATL03LA094)” > > It appears that both accident aircraft were being flow in > thunderstorms at the time they disintegrated. > > Do you suppose that the turbulence associated with > thunderstorms may have been a factor in these in-flight breakups? > > Just wondering. > > > > Lynn Farnsworth > --------------010606090100060907080305 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit I do reduce my speed to Va , in moderate to severe turbulence , not in light turbulence .
Alain Noireaux  L 320 F-PSDV


Sky2high@aol.com a écrit :
Topic changed so I changed the subject.
 
Generally, a Lancair 320 equipped with a 360 can easily push "cruise" into the yellow arc (> 180 KIAS) and stay there all day..  But to the point, I want to know how many have slowed their 320/360 to Va (143 KIAS) in turbulence?  Come on, raise your hands if you do that.... OK, I only see 2 or 3 hands.
 
I have difficulty slowing down to 143 KIAS and I would use a few degrees of flaps to keep the nose down.  I have slowed in nasty turbulence - to about 160 KIAS from 180.  For me, nasty is my guess of moderate turbulence as evaluated in a 320. 
 
So, for those of us frequently flying in the yellow arc and not slowing to Va in turbulence, how are we different than Stuart's controlled expansion of the flight envelope beyond Vne?  OK, that is from a structural aspect, not control surface flutter.
 
Well, let's see.  Below Va is the speed at which no combination of maneuver and gust load (<30 fps) at max gross weight cannot produce a positive air load that would create damage.
 
Va can be computed as Vs * SQRT(Limit load factor)
 
As originally set up, the stated limit was 4.5 Gs at 1685 pounds.  And let's say we use 68 KIAS as cruise configuration Vs (stall speed).
 
Then Va = 68* SQRT (4.5) = 68* 2.1 = 142.8 KIAS
 
 
Grayhawk
 
 
 
In a message dated 12/20/2009 6:35:13 P.M. Central Standard Time, sltroutman@hotmail.com writes:
It would seem to me that the maneuvering speed would be more of a concern than VNE but no mention of it yet. I bet that most have exceeded Va and never thought twice about it ??
----- Original Message -----
From: farnsworth
Sent: Sunday, December 20, 2009 6:51 AM
Subject: [LML] Re: Tone on list

 

 


“On August 09, 2005 N750F, a Lancair IV-P disintegrated in flight in a dive at Mach 0.62. It is not in your list as it happened in Canada (Transport Canada Report A05W0160).

In June of 2003 N29ME, a Lancair IV-P, disintegrated in flight after exceeding 253KTAS (274KIAS). (NTSB Report ATL03LA094)”

It appears that both accident aircraft were being flow in thunderstorms at the time they disintegrated.

Do you suppose that the turbulence associated with thunderstorms may have been a factor in these in-flight breakups?

Just wondering.

 

Lynn Farnsworth


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