Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Wed, 16 Feb 2005 20:35:30 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m24.mx.aol.com ([64.12.137.5] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 742116 for lml@lancaironline.net; Wed, 16 Feb 2005 18:36:06 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.5; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m24.mx.aol.com (mail_out_v37_r3.8.) id q.1e2.35a20a3c (16633) for ; Wed, 16 Feb 2005 18:35:11 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <1e2.35a20a3c.2f4532af@aol.com> X-Original-Date: Wed, 16 Feb 2005 18:35:11 EST Subject: Loose control surface hinges and vibration X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1108596911" X-Mailer: 9.0 Security Edition for Windows sub 5000 -------------------------------1108596911 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 1/4/2005 7:39:05 P.M. Central Standard Time, Christopher.Zavatson@udlp.com writes: About two years ago I started switching out all hinges with new reamed hinges and SS pins with a nominal clearance of 0.00175". The pin is 3/32" , 0.09375 welding rod and the MS hinge material is reamed to 0.0955 Chris, Thanks again. During my 9th condition inspection I decided to do something about the vibration in the stick and the loose hinges. (If any one is interested, check the thread "235 Near Miss" 1/4/05-1/6/05). No wonder the "looseness" had increased, the Teflon had flowed a bit but the original hinges had not worn at all. The hardest part was removing the teflon spagetti from some of the hinges. The finger-twisted reamer actually did no more than clean the gunk out of the old hinges except for one loop end that yielded a wee bit of metal. I then made hinge pins out of 3/32 SS welding rod and replaced the pins in the elevator, ailerons and flaps (the tightest pin fit of all), lightly lubricating the insertion operation with lithium grease. I decided to reuse my old hinges since they didn't exhibit much wear (when compared to new hinge material) and, although the fit was close, very little resistance was added. The results are that the elevator has no shake at all, the ailerons have reduced the dead band (from lash) to 1/8 inch (as measured by clamping one aileron and moving the other) and the flaps don't flap as much. In my flight test today, the stick operated smoothly with no apparent added resistance (note, both elevator and ailerons are trimmed via springs) and, most importantly, stick vibration had virtually disappeared. That is, the stick used to exhibit a minor coarse vibration laterally and major vibration in pitch - now there is only the slight and very fine airframe vibration. Smooth is better. When I looked outside, the ailerons were motionless (probably because I had my hands off the stick). Now I can more clearly identify the remaining vibration that is rpm dependent. Note that I also had to re-torque the engine-mount to firewall bolts - the third or fourth time in 9 annuals. Hmmmmm.... maybe I should check that every year. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Fair and Balanced Opinions at No Charge! There is an oxymoron in that, somewhere... -------------------------------1108596911 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 1/4/2005 7:39:05 P.M. Central Standard Time,=20 Christopher.Zavatson@udlp.com writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>About=20 two years ago I started switching out all hinges with new reamed
hinges= and=20 SS pins with a nominal clearance of 0.00175". The pin is
3/32" , 0.0937= 5=20 welding rod and the MS hinge material is reamed=20 to
0.0955

Chris,

Thanks again. During my 9th condition inspection I decided to do=20 something about the vibration in the stick and the loose hinges. (If any one= is=20 interested, check the thread "235 Near Miss" 1/4/05-1/6/05).

No wonder the "looseness" had increased, the Teflon had flowed a bit bu= t=20 the original hinges had not worn at all. The hardest part was removing= the=20 teflon spagetti from some of the hinges. The finger-twisted reamer=20 actually did no more than clean the gunk out of the old hinges except for on= e=20 loop end that yielded a wee bit of metal. I then made hinge pins=20= out=20 of 3/32 SS welding rod and replaced the pins in the elevator, ailerons and f= laps=20 (the tightest pin fit of all), lightly lubricating the insertion operat= ion=20 with lithium grease. I decided to reuse my old hinges since they= =20 didn't exhibit much wear (when compared to new hinge material) and,=20 although the fit was close, very little resistance was added.

The results are that the elevator has no shake at all, the ailerons hav= e=20 reduced the dead band (from lash) to 1/8 inch (as measured by clamping one=20 aileron and moving the other) and the flaps don't flap as much.

In my flight test today, the stick operated smoothly with no apparent a= dded=20 resistance (note, both elevator and ailerons are trimmed via springs) and, m= ost=20 importantly, stick vibration had virtually disappeared. That is, the s= tick=20 used to exhibit a minor coarse vibration laterally and major vibration in pi= tch=20 - now there is only the slight and very fine airframe vibration. Smoot= h is=20 better. When I looked outside, the ailerons were motionless (probably=20 because I had my hands off the stick).

Now I can more clearly identify the remaining vibration that is rp= m=20 dependent. Note that I also had to re-torque the engine-mount to firew= all=20 bolts - the third or fourth time in 9 annuals. Hmmmmm.... maybe I= =20 should check that every year.=20

Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Fai= r=20 and Balanced Opinions at No Charge!
There is an oxymoron in that,=20 somewhere...

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