X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Mon, 07 Dec 2009 09:41:58 -0500 Message-ID: X-Original-Return-Path: Received: from QMTA11.westchester.pa.mail.comcast.net ([76.96.59.211] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 4005648 for lml@lancaironline.net; Mon, 07 Dec 2009 05:27:21 -0500 Received-SPF: pass receiver=logan.com; client-ip=76.96.59.211; envelope-from=mjrav@comcast.net Received: from OMTA12.westchester.pa.mail.comcast.net ([76.96.62.44]) by QMTA11.westchester.pa.mail.comcast.net with comcast id EASS1d0030xGWP85BASlJh; Mon, 07 Dec 2009 10:26:46 +0000 Received: from mjr ([24.60.88.102]) by OMTA12.westchester.pa.mail.comcast.net with comcast id EASj1d0012CVLj43YASljm; Mon, 07 Dec 2009 10:26:46 +0000 X-Original-Message-ID: <004201ca7727$d59c9880$66583c18@mjr> From: "Mark Ravinski" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: Vne is NOT a meaningless number X-Original-Date: Mon, 7 Dec 2009 05:27:10 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003F_01CA76FD.EC9A5060" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1983 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1983 This is a multi-part message in MIME format. ------=_NextPart_000_003F_01CA76FD.EC9A5060 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable I think that when a plane fails from flutter it is actually caused by a = combination of speed and vibration. The indicated speed can be thought to be what causes a "load" or frontal = pressure. This is the pressure on your hand when stuck out the car = window and is what your airspeed instrument sees. The vibration or flutter is more dependent on true speed and would be = the rate of flutter of a handkerchief held out that same car window. In the aircraft structure, it's the true speed that establishes the rate = of flutter and is what must be considered to be exciting a natural = harmonic. To cause damage, there must be also enough load to drive the = amplitude up. Consider the space shuttle. It operates at what - 25,000 = MPH but in such thin air that the combined effect of load and vibration = is tolerated. I expect that to get an exact cockpit reading of Vne, you would need a = computer with a formula to weigh components of both true and indicated = speed and it would change with altitude, temperature and other variables = like fuel loading. High and fast military pilots are taught not to ever open their = parachute too soon after bailing out. One reason is that the chute pops = open at the true airspeed. The jolt can break your bones and has even = been reported to have ripped off someone's combat boots. Mark Ravinski ----- Original Message -----=20 From: Chat Daniel=20 To: lml=20 Sent: Thursday, December 03, 2009 10:13 AM Subject: [LML] Re: Vne is NOT a meaningless number Concerning the discussion of whether VNE is a function of indicated or = true airspeed, I recall reading that U2 pilots operated in the = =E2=80=9Ccoffin corner=E2=80=9D of some 5-10 MPH where stall was lower = limit and VNE and wings come off the upper. To me that seems like true = air speed would be limit on VNE. =20 Chat Daniel Super ES =20 =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Skip Slater Sent: Thursday, December 03, 2009 6:21 AM To: lml Subject: [LML] Re: Vne is NOT a meaningless number =20 "One IVP was lost years ago when it exceeded Vne." =20 Gene Long's ES also broke up in flight when it exceeded VNE during = it's inexplicable descent from cruse altitude a year an a half ago. =20 The fact it this: No amount of pilot skill will save a plane once = flutter begins to break it apart. If you knowingly exceed VNE, you are = a test pilot and the only way you'll know you went too fast is as your = plane is going down in pieces. Pilots who willfully ignore manufacturer = established limitations are accidents looking for a place to happen. = Pilots who brag about such exploits deserve a very wide berth. =20 I have to wonder what the instructors from HIPAT and LOBO would have = to say on this subject. If they're listening, I hope they'll chime in. =20 Skip Slater=20 =20 =20 -------------------------------------------------------------------------= ----- CONFIDENTIALITY NOTICE: This email transmission may contain = information that is proprietary, privileged, and/or confidential and is = intended exclusively for the person(s) to whom it is addressed. This = communication represents the originator=E2=80=99s personal views and = opinions, which do not necessarily reflect those of Century Bank & = Trust. This email and its attachments are believed to be free of any = virus or defect, but it is the responsibility of the recipient to ensure = that this is true. Century Bank does not accept responsibility or = liability for any loss or damage arising in any way from the receipt or = use of this email or for any errors or omissions in its contents which = may arise as a result of its transmission. Any use, copying, retention = or disclosure by any person other than the intended recipient or the = intended recipient=E2=80=99s designees is strictly prohibited. If you = are the intended recipient, you must treat the information in confidence = and in accordance with all laws related to the privacy and = confidentiality of such information. If you are not the intended = recipient or their designee, please notify the sender immediately by = return email and delete all copies of this email, including all = attachments. Thank You. CONFIDENTIALITY NOTICE: This email transmission may contain = information that is proprietary, privileged, and/or confidential and is = intended exclusively for the person(s) to whom it is addressed. This = communication represents the originator's personal views and opinions, = which do not necessarily reflect those of Century Bank & Trust. This = email and its attachments are believed to be free of any virus or = defect, but it is the responsibility of the recipient to ensure that = this is true. Century Bank does not accept responsibility or liability = for any loss or damage arising in any way from the receipt or use of = this email or for any errors or omissions in its contents which may = arise as a result of its transmission. Any use, copying, retention or = disclosure by any person other than the intended recipient or the = intended recipient's designees is strictly prohibited. If you are the = intended recipient, you must treat the information in confidence and in = accordance with all laws related to the privacy and confidentiality of = such information. If you are not the intended recipient or their = designee, please notify the sender immediately by return email and = delete all copies of this email, including all attachments. Thank You. ------=_NextPart_000_003F_01CA76FD.EC9A5060 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
I think that when a plane fails from = flutter it is=20 actually caused by a combination of speed and vibration.
The indicated speed can be thought to = be what=20 causes a "load" or frontal pressure.  This is the pressure on your = hand=20 when stuck out the car window and is what your airspeed instrument=20 sees.
The vibration or flutter is more = dependent on=20 true speed and would be the rate of flutter of a handkerchief held = out that=20 same car window.
In the aircraft structure, it's the = true speed that=20 establishes the rate of flutter and is what must be considered to be = exciting a=20 natural harmonic. To cause damage, there must be also enough load to = drive the=20 amplitude up.  Consider the space shuttle.  It operates at = what -=20 25,000 MPH but in such thin air that the combined effect of load and = vibration=20 is tolerated.
I expect that to get an exact cockpit = reading of=20 Vne, you would need a computer with a formula to weigh components of = both true=20 and indicated speed and it would change with altitude, temperature and = other=20 variables like fuel loading.
 
High and fast military pilots are = taught not to=20 ever open their parachute too soon after bailing out.  One reason = is that=20 the chute pops open at the true airspeed.  The jolt can break your = bones=20 and has even been reported to have ripped off someone's combat=20 boots.
 
Mark Ravinski
 
 
----- Original Message -----
From:=20 Chat Daniel =
To: lml
Sent: Thursday, December 03, = 2009 10:13=20 AM
Subject: [LML] Re: Vne is NOT a = meaningless number

Concerning=20 the discussion of whether VNE is a function of indicated or true = airspeed, I=20 recall reading that U2 pilots operated in the =E2=80=9Ccoffin = corner=E2=80=9D of some 5-10 MPH=20 where stall was lower limit and VNE and wings come off the = upper.  To me=20 that seems like true air speed would be limit on = VNE.

 

Chat=20 Daniel

Super=20 ES 

 

From: Lancair = Mailing=20 List [mailto:lml@lancaironline.net] On Behalf Of Skip=20 Slater
Sent: Thursday, December 03, 2009 6:21 = AM
To:=20 lml
Subject: [LML] Re: Vne is NOT a meaningless=20 number

 

"One IVP = was lost=20 years ago when it exceeded Vne."

 

Gene = Long's ES also=20 broke up in flight when it exceeded VNE during it's inexplicable = descent from=20 cruse altitude a year an a half ago.

 

The fact = it=20 this:  No amount of pilot skill will save a plane once flutter = begins to=20 break it apart.  If you knowingly exceed VNE, you are a test = pilot and=20 the only way you'll know you went too fast is as your plane is going = down in=20 pieces.  Pilots who willfully ignore manufacturer established = limitations=20 are accidents looking for a place to happen.  Pilots who brag = about such=20 exploits deserve a very wide berth.

 

I have to = wonder=20 what the instructors from HIPAT and LOBO would have to say on this=20 subject.  If they're listening, I hope they'll chime=20 in.

 

Skip=20 Slater 

 

 


CONFIDENTIALITY NOTICE: This = email=20 transmission may contain information that is proprietary, privileged, = and/or=20 confidential and is intended exclusively for the person(s) to whom it = is=20 addressed. This communication represents the originator=E2=80=99s = personal views and=20 opinions, which do not necessarily reflect those of Century Bank & = Trust.=20 This email and its attachments are believed to be free of any virus or = defect,=20 but it is the responsibility of the recipient to ensure that this is = true.=20 Century Bank does not accept responsibility or liability for any loss = or=20 damage arising in any way from the receipt or use of this email or for = any=20 errors or omissions in its contents which may arise as a result of its = transmission. Any use, copying, retention or disclosure by any person = other=20 than the intended recipient or the intended recipient=E2=80=99s = designees is strictly=20 prohibited. If you are the intended recipient, you must treat the = information=20 in confidence and in accordance with all laws related to the privacy = and=20 confidentiality of such information. If you are not the intended = recipient or=20 their designee, please notify the sender immediately by return email = and=20 delete all copies of this email, including all attachments. Thank=20 You.
CONFIDENTIALITY NOTICE: This email transmission may = contain=20 information that is proprietary, privileged, and/or confidential and = is=20 intended exclusively for the person(s) to whom it is addressed. This=20 communication represents the originator's personal views and opinions, = which=20 do not necessarily reflect those of Century Bank & Trust. This = email and=20 its attachments are believed to be free of any virus or defect, but it = is the=20 responsibility of the recipient to ensure that this is true. Century = Bank does=20 not accept responsibility or liability for any loss or damage arising = in any=20 way from the receipt or use of this email or for any errors or = omissions in=20 its contents which may arise as a result of its transmission. Any use, = copying, retention or disclosure by any person other than the intended = recipient or the intended recipient's designees is strictly = prohibited. If you=20 are the intended recipient, you must treat the information in = confidence and=20 in accordance with all laws related to the privacy and confidentiality = of such=20 information. If you are not the intended recipient or their designee, = please=20 notify the sender immediately by return email and delete all copies of = this=20 email, including all attachments. Thank = You. ------=_NextPart_000_003F_01CA76FD.EC9A5060--