X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 10 Dec 2008 00:50:58 -0500 Message-ID: X-Original-Return-Path: Received: from imo-d05.mx.aol.com ([205.188.157.37] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with ESMTP id 3350995 for lml@lancaironline.net; Tue, 09 Dec 2008 12:43:22 -0500 Received: from Mquinns@aol.com by imo-d05.mx.aol.com (mail_out_v39.1.) id q.c2d.4ce1b18d (34910) for ; Tue, 9 Dec 2008 12:42:57 -0500 (EST) Received: from smtprly-mb03.mx.aol.com (smtprly-mb03.mx.aol.com [64.12.207.150]) by cia-da02.mx.aol.com (v121_r5.1) with ESMTP id MAILCIADA027-5c6b493eae1a18d; Tue, 09 Dec 2008 12:42:55 -0500 Received: from FWM-D35 (fwm-d35.webmail.aol.com [205.188.162.11]) by smtprly-mb03.mx.aol.com (v121_r5.1) with ESMTP id MAILSMTPRLYMB031-5c6b493eae1a18d; Tue, 09 Dec 2008 12:42:50 -0500 References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] Re: outback gear doors-vibration is back X-Original-Date: Tue, 09 Dec 2008 12:42:50 -0500 X-AOL-IP: 207.126.196.16 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: mquinns@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CB283CB0F2471E_5EC_42A_FWM-D35.sysops.aol.com" X-Mailer: AOL Webmail 39997-STANDARD Received: from 207.126.196.16 by FWM-D35.sysops.aol.com (205.188.162.11) with HTTP (WebMailUI); Tue, 09 Dec 2008 12:42:50 -0500 X-Original-Message-Id: <8CB283CB0D0E5FA-5EC-20A@FWM-D35.sysops.aol.com> X-Spam-Flag:NO ----------MB_8CB283CB0F2471E_5EC_42A_FWM-D35.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Grayhawk, =C2=A0=C2=A0 The wheel well to cockpit openings are not sealed. The leading=20= edge of the doors (inner and outer) are firmly seated against the flanges so= =C2=A0I don't believe there is air leaking past the doors at this point. Als= o, the other pictures (air to air)=C2=A0never show anything that indicates= =C2=A0the leading edge is allowing air to flow in.=C2=A0The leading edge of=20= the doors always appear tightly sealed at all speeds.=C2=A0 Mark Quinn -----Original Message----- From: Sky2high@aol.com To: lml@lancaironline.net Sent: Tue, 9 Dec 2008 8:43 am Subject: [LML] Re: outback gear doors-vibration is back "Sucked out" is a weird concept on the bottom of the wing where one would ex= pect hi pressure.=C2=A0 Perhaps airflow over a surface produces a local=C2= =A0low pressure even though the pressure on the bottom is greater than that=20= on the top?=C2=A0 However, if any air enters at the door leading edge, it is= far easier to understand since the door is curved and could act like an inv= erted wing.=C2=A0 Then, when the rear is in the slip stream, the forward edg= e is forced closed and the "wing" stops flying, returning to the start state= where air once again enters at the leading edge. Thus, the buzz. =C2=A0 Is the wheel well sealed to the cockpit, thus the door does not benefit from= the low pressure in the cockpit trying to suck the door in.=C2=A0=20 =C2=A0 Interrrrrresting......... =C2=A0 Grayhawk =C2=A0 In a message dated 12/8/2008 12:55:59 P.M. Central Standard Time, harryleagu= e@comcast.net=20 writes: Just a thought:=C2=A0 would a couple of air vents in the doors solve the pro= blem?=C2=A0=C2=A0 Start small and move larger until the noise stops or the d= oors stay shut. =C2=A0 Regards, Harry League =C2=A0 =C2=A0 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of marv@= lancair.net Sent: Saturday, December 06, 2008 21:46 PM To: lml@lancaironline.net Subject: [LML] Re: outback gear doors-vibration is back =C2=A0 Posted for mquinns@aol.com: =C2=A0Dom, =C2=A0=C2=A0=C2=A0=C2=A0 AC-DC is not to my taste but listening to them woul= d be far more musical=20 and pleasant than gear door rumblings. Attached is a close up picture of a=20 musical nocturne. =C2=A0 =C2=A0Mark =C2=A0 =C2=A0 =C2=A0-----Original Message----- From: Dominic V. Crain =C2=A0To: lml@lancaironline.net =C2=A0Sent: Fri, 5 Dec 2008 12:06 pm =C2=A0Subject: [LML] Re: outback gear doors-vibration is back =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0I would think that the gear doors rumbling would be far more musical t= han=20 listening to AC-DC. =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Cheers =C2=A0 =C2=A0Dom =C2=A0 =C2=A0VH-CZJ =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of=20 mquinns@aol.com =C2=A0Sent: Friday, 5 December 2008 3:25 PM =C2=A0To: lml@lancaironline.net =C2=A0Subject: [LML] Re: outback gear doors-vibration is back =C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Gerard, =C2=A0=C2=A0=C2=A0 I had the same problem. Whenever the airspeed started mov= ing past 210=20 knots a buzz would start and then turn20into a rumble as the plane went fast= er.=20 If the aircraft was decelerated......to a speed around 205 knots, the rumbli= ng=20 and buzzing would disappear but would reappear if the aircraft accelerated=20 back above 210 knots. I was certain it was the nose gear door (made from=20 fiberglass) so I took the advice in archive and fabricated a much stiffer=20 aluminum door. To my surprise the buzzing and rumbling problem was still the= re=20 over certain speeds.!!!!???!!!! Fortunately for me, I live at at a place whe= re=20 we formation fly to breakfast every Saturday and I usually fly with the SX-3= 00=20 guys. One of these friends volunteered to go up with me and formate under me= =20 to=20 =C2=A0see if the problem could be observed. Apparently, the main gear doors=20 trailing edges are being sucked out into the slipstream at certain airspeeds= .=20 We repeated the speed runs (accelerate/decelerate) and proble! m was clear. =C2=A0=C2=A0=C2=A0 My plane does have a difference with yours which is, even= though I have=20 the outback gear, I decided=C2=A0to use the original cutout doors thinking t= hey=20 would create less drag. Don't know whether they do or not but have been unab= le=20 after many different attempts to keep the doors closed at high speed. In=20 January I will be racing and afterwards plan on doing a major condition=20 inspection (demating wings, removing all control surfaces, etc) and at that=20 time will fit the original outback gear doors from the option kit. They do=20 appear to be stiffer (I hope they don't generate m ore drag). I hope that this=20 cures my problem. Some of the Reno racers have recommended stiffening gear=20 doors because this is a common problem for them while racing. If you find a=20 magic bullet to correct the problem, please post=C2=A0it.=C2=A0 =C2=A0 =C2=A0Mark Quinn =C2=A0Lancair 360 =C2=A0Spruce Creek Fly-in, Florida =C2=A0 =C2=A0 =C2=A0-----Original Message----- From: gerardoconnell@optusnet.com.au =C2=A0To: lml@lancaironline.net =C2=A0Sent: Wed, 3 Dec 2008 9:15 pm =C2=A0Subject: [LML] outback gear doors-vibration is back =C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Hi Ian and those whom have had gear door problems =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0-Gerard from Down Under/Up Over has gremlins again =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Hope you're going well and enjoying you're flying. I'm just writing a=20= quick=20 note=20 =C2=A0 =C2=A0both on and off =C2=A0list as we've been over this ground before.=20 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Do you recall discussing the buzzing noise I had some time back which=20= I=20 resolved=20 =C2=A0 =C2=A0both by removing the nose gear door and overlapping the main and inboa= rd gear=20 =C2=A0 =C2=A0doors to get better "purchase" and stop vibration. =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Well guess what?=C2=A0=C2=A0 Thhe noise is now starting to return-I in= itially thought I=20 =C2=A0 =C2=A0had the bass turned up too much whilst listening to AC -DC but even wi= th the=20 =C2=A0 =C2=A0radio off I can appreciate the buzz from outside the aircraft.=20 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Perhaps I need to listen to Rob bie Williams instead? =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0I originally spent thousands of $ trying various solutions to this pro= blem=20 and=20 =C2=A0 =C2=A0the final fix has worked for about 200 hours. I understand that some h= ave=20 also=20 =C2=A0 =C2=A0extended the door hinge/bracket to address this problem. =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0In short, my question is this-did you have this buzzing/vibration prob= lem and=20 =C2=A0 =C2=A0what methods did you employ before removing the inner gear doors altog= ether?=20 Is=20 =C2=A0 =C2=A0this my best short cut to making the problem go away once and for all? =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Your thoughts would be appreciated including and issues you mar or may= nopt=20 have=20 =C2=A0 =C2=A0experienced after removing the inner doors. =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Cheers, =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Gerard =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0-- =C2=A0 For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Listen to 350+ music, sports, & news radio stations =E2=80=93 includin= g songs for the=20 holidays =E2=80=93 FREE while you browse. =C2=A0Start Listening Now!=20 =C2=A0 =C2=A0 =C2=A0 Make your life easier with all your friends, email, and favorite sites in on= e place. Try it now. ----------MB_8CB283CB0F2471E_5EC_42A_FWM-D35.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" Grayhawk,
   The wheel well to cockpit openings are not sealed. The leading=20= edge of the doors (inner and outer) are firmly seated against the flanges so=  I don't believe there is air leaking past the doors at this point. Als= o, the other pictures (air to air) never show anything that indicates&n= bsp;the leading edge is allowing air to flow in. The leading edge of th= e doors always appear tightly sealed at all speeds. 

Mark Quinn


-----Original Message-----
From: Sky2high@aol.com
To: lml@lancaironline.net
Sent: Tue, 9 Dec 2008 8:43 am
Subject: [LML] Re: outback gear doors-vibration is back

"Sucked out" is a weird concept on the bottom of the wing where one wou= ld expect hi pressure.  Perhaps airflow over a surface produces a local=  low pressure even though the pressure on the bottom is greater than th= at on the top?  However, if any air enters at the door leading edge, it= is far easier to understand since the door is curved and could act like an=20= inverted wing.  Then, when the rear is in the slip stream, the forward=20= edge is forced closed and the "wing" stops flying, returning to the start st= ate where air once again enters at the leading edge. Thus, the buzz.
 
Is the wheel well sealed to the cockpit, thus the door does not benefit= from the low pressure in the cockpit trying to suck the door in. 
 
Interrrrrresting.........
 
Grayhawk
 
In a message dated 12/8/2008 12:55:59 P.M. Central Standard Time, harryleague@comcast.net writes:
Just a thought: =20= would a couple of air vents in the doors solve the problem?   Star= t small and move larger until the noise stops or the doors stay shut.=
 
Regards,=
Harry League
=  
 
From: Lancair Mailing List [mailto:= lml@lancaironline.net] On Behalf Of= marv@lancair.net
Sent: Saturday, December 06,= 2008 21:46 PM
To: lml@lancaironline.net
Subject: [LML] Re: outback g= ear doors-vibration is back
 

Posted for mquinns@aol.com:

 Dom,
     AC-DC is not to my taste but listening to them woul= d be far more musical
and pleasant than gear door rumblings. Attached is a close up picture of a <= br> musical nocturne.
 
 Mark
 
 
 -----O riginal Message-----
From: Dominic V. Crain <domcrain@t= pg.com.au>
 To: lml@lancaironline.net=
 Sent: Fri, 5 Dec 2008 12:06 pm
 Subject: [LML] Re: outback gear doors-vibration is back
 
 
 
 
 I would think that the gear doors rumbling would be far more musical t= han
listening to AC-DC.
 
  
 
 Cheers
 
 Dom
 
 VH-CZJ
 
  
 
 
From: Lancair Mailing List [mailto= :lml@lancaironline.net] On Behalf Of
mquinns@aol.com
 Sent: Friday, 5 December 2008 3:25 PM
 To: lml@lancaironline.net=
 Subject: [LML] Re: outback gear doors-vibration is back
 
 
  
 
 Gerard,
    I had the same problem. Whenever the airspeed started mov= ing past 210
knots a buzz would start and then turn into a rumble as the plane went faste= r.
If the aircraft was decelerated......to a speed around 205 knots, the rumbli= ng
and buzzing would disappear but would reappear if the aircraft accelerated <= br> back above 210 knots. I was certain it was the nose gear door (made from fiberglass) so I took the advice in archive and fabricated a much stiffer aluminum door. To my surprise the buzzing and rumbling problem was still the= re
over=20 certain speeds.!!!!???!!!! Fortunately for me, I live at at a place where we formation fly to breakfast every Saturday and I usually fly with the SX-3= 00
guys. One of these friends volunteered to go up with me and formate under me=
to
 see if the problem could be observed. Apparently, the main gear doors=20=
trailing edges are being sucked out into the slipstream at certain airspeeds= .
We repeated the speed runs (accelerate/decelerate) and proble! m was clear.<= br>     My plane does have a difference with yours which is, even= though I have
the outback gear, I decided to use the original cutout doors thinking t= hey
would create less drag. Don't know whether they do or not but have been unab= le
after many different attempts to keep the doors closed at high speed. In January I will be racing and afterwards plan on doing a major condition
inspection (demating wings, removing all control surfaces, etc) and at that=20=
time will fit the original outback gear doors from the option kit. They do <= br> appear to be stiffer (I hope they don't generate more drag). I hope that thi= s
cures my problem. Some of the Reno racers have recommended stiffening gear <= br> doors because this is a common problem for them while racing. If you find a=20=
magic bullet to correct the problem, please post it. 
 
 Mark Quinn
 Lancair 360
 Spruce Creek Fly-in, Florida
 
 
 -----Original Message-----
From:=3D2 0gerardoconnell@optusnet.c= om.au
 To: lml@lancaironline.net=
 Sent: Wed, 3 Dec 2008 9:15 pm
 Subject: [LML] outback gear doors-vibration is back
 
 
  
 
  
 
 Hi Ian and those whom have had gear door problems
 
  
 
 -Gerard from Down Under/Up Over has gremlins again
 
  
 
  
 
 Hope you're going well and enjoying you're flying. I'm just writing a=20= quick
note
 
 both on and off
 list as we've been over this ground before.
 
  
 
 Do you recall discussing the buzzing noise I had some time back which=20= I
resolved
 
 both by removing the nose gear door and overlapping the main and inboa= rd gear
 
 doors to get better "purchase" and stop vibration.
 
  
 
 Well guess what?   Thhe noise is now starting to return-I in= itially thought I
 
 had the bass turned up too much whilst listening to AC -DC but even wi= th the
 
 radio off I can appreciate the buzz from outside the aircraft.
 
  
 
 Perhaps I need to listen to Robbie Williams instead?
 
  
 
 I originally spent thousands of $ trying various solutions to this pro= blem
and
 
 the final fix has worked for about 200 hours. I understand that some h= ave
also
 
 extended the door hinge/bracket to address this problem.
 
  
 
 In short, my question is this-did you have this buzzing/vibration prob= lem and
 
 what methods did you employ before removing the inner gear doors altog= ether?
Is
 
 this my best short cut to making the problem go away once and for all?=
 
  
 
 Your thoughts would be appreciated including and issues you mar or may= nopt
have
 
 experienced after removing the inner doors.
 
  
 
  
 
 Cheers,
 
  
 
 Gerard
 
  
 
  
 
  
 
  
 
  
 
 --
 
For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.= html
 
 
 
  
 
 
 
 Listen to 350+ music, sports, & news radio stations =E2=80=93 incl= uding songs for the
holidays =E2=80=93 FREE while you browse.
 Start Listening Now!
 
 
 




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