X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 21 Nov 2011 08:29:02 -0500 Message-ID: X-Original-Return-Path: Received: from imr-da01.mx.aol.com ([205.188.105.143] verified) by logan.com (CommuniGate Pro SMTP 5.4.2) with ESMTP id 5207838 for lml@lancaironline.net; Sun, 20 Nov 2011 19:58:59 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.143; envelope-from=Sky2high@aol.com Received: from mtaomg-mb03.r1000.mx.aol.com (mtaomg-mb03.r1000.mx.aol.com [172.29.41.74]) by imr-da01.mx.aol.com (8.14.1/8.14.1) with ESMTP id pAL0wAWR008242 for ; Sun, 20 Nov 2011 19:58:10 -0500 Received: from core-mtb004a.r1000.mail.aol.com (core-mtb004.r1000.mail.aol.com [172.29.234.205]) by mtaomg-mb03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 1C1CAE000085 for ; Sun, 20 Nov 2011 19:58:10 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <3fce8.1dadbb31.3bfafc21@aol.com> X-Original-Date: Sun, 20 Nov 2011 19:58:10 -0500 (EST) Subject: Re: [LML] Legacy vibrations resolved X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_3fce8.1dadbb31.3bfafc21_boundary" X-Mailer: AOL 9.6 sub 5004 X-Originating-IP: [207.200.122.33] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:465212576:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d294a4ec9a2225e5b --part1_3fce8.1dadbb31.3bfafc21_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Steve, =20 One final Check: Make sure the engine mount bolts thru the firewall are= =20 fully torqued at each annual condition inspection as they will become =20 "loose" over time and lead to unnecessary vibration. The hinge pin fix is = for a=20 symptom, not the cause. =20 Grayhawk =20 =20 In a message dated 11/20/2011 8:48:28 A.M. Central Standard Time, =20 mcmess1919@yahoo.com writes: =20 Our Legacy has had a pitch vibration in the stick that comes and goes. It= =20 seems to be related to about 50% fuel load or less and reduced but stable= =20 power. The plane has about 275 hours and this has been going on since the= =20 first 40 hours. When it is vibrating in level flight (approximately 2=20 cycles per second and the stick is visibly moving in a pronounced shake) i= t=20 will continue to vibrate when pitched up at about 1.5 G. After the pitch = up,=20 when pitched down to less than 1 G, the vibration will quit. After=20 working thru many of the same contact points firewall forward and the gear= doors=20 Paul Miller had, I still had the vibration. All the while, I'm thinking,= =20 this is a great way to initiate flutter. I might add, I very carefully=20 rebalanced the control surfaces after painting. =20 I mentioned the problem to Chris Zavatson at the Lancair Breakfast Fly-In= =20 at Willows, CA.. Chris asked if I had checked the control and trim hinges= =20 for play. That was easy, I check them every pre-flight. Only not the way= =20 Chris checks them. He pushes and pulls looking at the hinge. See video = =20 _http://www.n91cz.com/HingePlay/hinges.htm_=20 (http://www.n91cz.com/HingePlay/hinges.htm) =20 I replaced the Pitch Trim Hinge Pin with Stainless Steel (3/32=E2=80=9D - = .09375)=20 welding wire. Now, no play can be seen in the push pull test. We have pu= t=20 20+ hours on with the new SS hinge pin and no more stick shake. I=20 included Paul=E2=80=99s post of problem areas (see below) since I had some= of them too. =20 Steve Colwell Legacy RG 310 hours=20 Sent: Monday, April 12, 2010 6:47 AM To: lml@lancaironline.net Subject: [LML] Legacy vibrations resolved=20 I had written about vibrations in the 300 hour Legacy engine =20 compartment. Many wrote about their fixes. I am happy to report that = =20 the following worked for me:=20 1) Changed engine isolators last year (no difference)=20 2) enlarged cutout on nose gear door stiffener. After repeatedly seeing= =20 new witness marks I did a retraction test and saw the interference is much= =20 larger than I expected. I trimmed another 1/8 inch from the cutout. This= =20 cutout prevents interference from the bolt attaching the linkage to the no= se=20 gear on both sides. The co-pilot side needed a larger cutout. White=20 primer was used to show the marks after each flight. I think this was=20 transmitting a lot of cowl vibration.=20 3) I sprayed white primer on the areas contacting the baffling. I =20 found three hard hit areas and this is using the factory white powder=20 coated baffling. Two areas at the front of the #5 cylinder needed bending= away=20 from the cowl. Another area just above the oil cooler on the top side of= =20 the cowl was hitting. The #5 EGT probe was hitting. =20 The #5 forward rocker cover was hitting on the bottom and was peened about= =20 a 1/4 to match the form of the cowl. I removed the rocker cover to check= =20 for clearance with the rocker arm.=20 4) Baffling repairs were made to areas that were not tight against the =20 cowl. This significantly reduced the CHTs. I used the cooling and =20 drag reduction data on lml from owners to help make small but helpful=20 changes in the baffling.=20 5) The prop governor cable was a hard hit on the metal baffling and was=20 trimmed.=20 6) The nose gear doors had a slight overlap which was trimmed so they=20 close tight with no gaps.=20 7) Both main gear inner and outer doors were adjusted to be flush and=20 tight when retracted. This took a significant amount of time involving sm= all=20 hinge adjustments and testing of each individual attachment link on the=20 outer doors to get the right length before attaching both links for the fi= nal=20 test. I say this because the two links are slightly different in length a= nd=20 geometry. I found one was a little longer than required and actually=20 twisted the door slightly open when both links were attached. This was no= t=20 evident until I retracted the gear using only single links.=20 8) the large circular baffle behind the prop is cracked in two places and= =20 remains that way until a fix can be made. This appears to be from a tight= =20 fit and needs to be measured for a new smaller piece. This is a large=20 crack that could easily be flopping around in flight and somehow interferi= ng=20 with the cooling process.=20 9) removed the quick drain for oil and replaced with the factory plug. = =20 I have lots of clearance and may put the quick drain back in.=20 The net result is now I have a smooth engine compartment. My symptoms = =20 included a difficult propeller balancing as we could never exactly home in= =20 on a solution. The vibration was small at 2700 rpm and takeoff but=20 increased significantly with rpm reduction. I attribute that to the highe= r=20 torque twisting the engine closer to the left side of the baffling. The= =20 vibration was evident in the cockpit, cowling and when looking at the wing= s. The=20 next project will be to replace the silicone baffle with new material and= =20 replace the circular baffle plate behind the prop and replace the left sid= e=20 metal baffle to better fit the cowl line near the #5 cylinder. Many thank= s=20 to all the suggestions that made this easier to do.=20 Paul Miller=20 N357V Legacy RG --part1_3fce8.1dadbb31.3bfafc21_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Steve,
 
One final Check:  Make sure the engine mount bolts thru the firew= all=20 are fully torqued at each annual condition inspection as they will become= =20 "loose" over time and lead to unnecessary vibration.  The hinge pin fi= x is=20 for a symptom, not the cause.
 
Grayhawk
 
In a message dated 11/20/2011 8:48:28 A.M. Central Standard Time,=20 mcmess1919@yahoo.com writes:
=

Our Legacy has had a pitch vibration in the stick= that=20 comes and goes.  It seems to be related to about 50% fuel load or le= ss=20 and reduced but stable power.  The plane has about 275 hours and thi= s has=20 been going on since the first 40 hours.  When it is vibrating in lev= el=20 flight (approximately 2 cycles per second and the stick is visibly moving= in a=20 pronounced shake) it will continue to vibrate when pitched up at about 1.= 5=20 G.  After the pitch up, when pitched down to less than 1 G, the vibr= ation=20 will quit.   After working thru many of the same contact points= =20 firewall forward and the gear doors Paul Miller had, I still had the=20 vibration. All the while, I'm thinking, this is a great way to initiate= =20 flutter.  I might add, I very carefully rebalanced the control surfa= ces=20 after painting.

 

I mentioned the problem to Chris Zavatson at the = Lancair=20 Breakfast Fly-In at Willows, CA..  Chris asked if I had checked the= =20 control and trim hinges for play.  That was easy, I check them every= =20 pre-flight.  Only not the way Chris checks them. He pushes and pulls= =20 looking at the hinge.  See video  http://www.n91cz.com/H= ingePlay/hinges.htm=20

 

I replaced the Pitch Trim Hinge Pin with Stainles= s Steel=20 (3/32=E2=80=9D - .09375) welding wire.  Now, no play can be seen in = the push pull=20 test.  We have put 20+ hours on with the new SS hinge pin and no mor= e=20 stick shake.  I included Paul=E2=80=99s post of problem areas (see b= elow) since I=20 had some of them too.  

 

Steve Colwell  Legacy RG 310 hours

 


Sent: Monday, April 12, 2010 6:47 AM
To:= =20 lml@lancaironline.net
Subject: [LML] Legacy vibrations=20 resolved

 

I had written about vibrations in the 300 hour Le= gacy=20 engine

compartment.  Many wrote about their=20 fixes.   I am happy to report that

the following worked for me:

 

1) Changed engine isolators last year (no=20 difference)

2) enlarged cutout on nose gear door stiffener.&n= bsp;=20 After repeatedly seeing new witness marks I did a retraction test and saw= the=20 interference is much larger than I expected.  I trimmed another 1/8 = inch=20 from the cutout.  This cutout prevents interference from the bolt=20 attaching the linkage to the nose gear on both sides.  The co-pilot = side=20 needed a larger cutout.  White primer was used to show the marks aft= er=20 each flight.  I think this was transmitting a lot of cowl=20 vibration.

3) I sprayed white primer on the areas contacting= the=20 baffling.   I

found three hard hit areas and this is using the = factory=20 white powder coated baffling.  Two areas at the front of the #5 cyli= nder=20 needed bending away from the cowl.  Another area just above the oil= =20 cooler on the top side of the cowl was hitting.  The #5 EGT probe wa= s=20 hitting. 

The #5 forward rocker cover was hitting on the bo= ttom=20 and was peened about a 1/4 to match the form of the cowl.  I removed= the=20 rocker cover to check for clearance with the rocker arm.

4) Baffling repairs were made to areas that were = not=20 tight against the

cowl.   This significantly reduced the= =20 CHTs.  I used the cooling and

drag reduction data on lml from owners to help ma= ke=20 small but helpful changes in the baffling.

5) The prop governor cable was a hard hit on the = metal=20 baffling and was trimmed.

6) The nose gear doors had a slight overlap which= was=20 trimmed so they close tight with no gaps.

7) Both main gear inner and outer doors were adju= sted to=20 be flush and tight when retracted.  This took a significant amount o= f=20 time involving small hinge adjustments and testing of each individual=20 attachment link on the outer doors to get the right length before attachi= ng=20 both links for the final test.  I say this because the two links are= =20 slightly different in length and geometry.  I found one was a little= =20 longer than required and actually twisted the door slightly open when bot= h=20 links were attached.  This was not evident until I retracted the gea= r=20 using only single links.

8) the large circular baffle behind the prop is c= racked=20 in two places and remains that way until a fix can be made.  This ap= pears=20 to be from a tight fit and needs to be measured for a new smaller piece.&= nbsp;=20 This is a large crack that could easily be flopping around in flight and= =20 somehow interfering with the cooling process.

9) removed the quick drain for oil and replaced w= ith the=20 factory plug. 

I have lots of clearance and may put the quick dr= ain=20 back in.

 

The net result is now I have a smooth engine=20 compartment.   My symptoms

included a difficult propeller balancing as we co= uld=20 never exactly home in on a solution.  The vibration was small at 270= 0 rpm=20 and takeoff but increased significantly with rpm reduction.  I attri= bute=20 that to the higher torque twisting the engine closer to the left side of = the=20 baffling.  The vibration was evident in the cockpit, cowling and whe= n=20 looking at the wings.  The next project will be to replace the silic= one=20 baffle with new material and replace the circular baffle plate behind the= prop=20 and replace the left side metal baffle to better fit the cowl line near t= he #5=20 cylinder.  Many thanks to all the suggestions that made this easier = to=20 do.

 

Paul Miller

N357V Legacy=20 RG

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