X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-d08.mx.aol.com ([205.188.109.207] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTPS id 6394215 for lml@lancaironline.net; Sun, 28 Jul 2013 14:39:45 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.109.207; envelope-from=Sky2high@aol.com Received: from mtaomg-ma06.r1000.mx.aol.com (mtaomg-ma06.r1000.mx.aol.com [172.29.41.13]) by omr-d08.mx.aol.com (Outbound Mail Relay) with ESMTP id 0DA3A700000BA for ; Sun, 28 Jul 2013 14:39:11 -0400 (EDT) Received: from core-mtb004c.r1000.mail.aol.com (core-mtb004.r1000.mail.aol.com [172.29.234.205]) by mtaomg-ma06.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 97DADE000082 for ; Sun, 28 Jul 2013 14:39:10 -0400 (EDT) From: Sky2high@aol.com Full-name: Sky2high Message-ID: <8cc9b.7e9a5e70.3f26bf4e@aol.com> Date: Sun, 28 Jul 2013 14:39:10 -0400 (EDT) Subject: Re: [LML] Re: Potential Problem-Engine Vibration To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_8cc9b.7e9a5e70.3f26bf4e_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1375036751; bh=bUo4IbPSPq6CB+XbEliGRVaS9hYSyDS8U3/ce9CyAcM=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=B3kTrdDQE+z3wVetFl4aGQpjXLdBOUmnVSBd7DpqGmfBXbYDdUe5mQcdk1SJfS7t8 KFhxIyAf/1w6YrY5//IS3eoh4J09g5PEd5cmN08GkvBduT3w4NJCepE0QXzGmzEWiZ dSwgEINRMfA+OKNkkvGnzjH8hkiItQjy450tNNUk= x-aol-sid: 3039ac1d290d51f5654e26a9 --part1_8cc9b.7e9a5e70.3f26bf4e_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Craig, et al, Interesting ...... A friend with a 600 hr, 6 cyl Continental engine switched from a 2 blade to a 3 blade prop with resulting obnoxious vibration and, after weeks of meticulously ridding the engine compartment of anything that moved from touching the fuselage or cowling, consulted a gray haired A&P who related how the wear pattern against bearings by torque pulses from using a 2-blade and a 3-blade prop would be in different places in the engine. He went back to a 2-blade prop and all vibration disappeared. There was an example of a change affected by how the engine bearing had worn that definitely resulted in inducing vibration. Grayhawk In a message dated 7/28/2013 1:21:29 P.M. Central Daylight Time, craig@skybolt.net writes: It could be possible for wear or manufacturing process to allow one blade to have more play in pitch operation than the others. Blue Skies, Craig Schulze On Jul 27, 2013, at 5:36 PM, _vtailjeff@aol.com_ (mailto:vtailjeff@aol.com) wrote: How is that mechanically possible? All blades are attached to the same pitch change mechanism. J Sent from my iPad On Jul 27, 2013, at 12:34 PM, Steve Colwell <_mcmess1919@yahoo.com_ (mailto:mcmess1919@yahoo.com) > wrote: That is a possibility I had not considered, I will ask Hartzell about it. Another possibility is the movable crankshaft counter weights failing to position correctly. Steve Colwell ____________________________________ From: Craig Schulze <_craig@skybolt.net_ (mailto:craig@skybolt.net) > To: Steve Colwell <_mcmess1919@yahoo.com_ (mailto:mcmess1919@yahoo.com) > Cc: "_lml@lancaironline.net_ (mailto:lml@lancaironline.net) " <_lml@lancaironline.net_ (mailto:lml@lancaironline.net) > Sent: Friday, July 26, 2013 7:42 AM Subject: Re: Potential Problem-Engine Vibration It sounds to me that you may have an issue with your prop hub not changing the pitch exactly the same on all the blades. The vibration you are feeling is one blade taking a larger bite of air and then causing everything to wobble. It settles in sometimes but when you change the power setting the pitch on the prop is adjusted by the hub unevenly. Blue Skies, Craig Schulze Lancair N73S On Jul 25, 2013, at 1:22 PM, "Steve Colwell" <_mcmess1919@yahoo.com_ (mailto:mcmess1919@yahoo.com) > wrote: In the first 40 hours I had vibration so severe it caused stick shake. This has continued intermittently more or less for almost 400 hours. First I found and fixed several Cowl Interference locations, then adjusted and notched the hat section of the nose gear door. At about 50 hours I paid Barrett to tear down the engine to replace the Performance pistons (prematurely worn top rings) with stock ECI pistons. Also found a cracked case. We had the Kelly Alternator balanced and rebuilt at a shop recommended by Bill Bainbridge of B & C. Sorry I can't remember the name, the Legacy file is in Texas. I rounded the leading edges of the elevator counter weights when building so I temporarily squared them off to go back to the stock shape for testing. All gear doors were checked in flight with video camera. The pitch trim hinge pin had play, I replaced it per Chris Zavatson's web page. Along the way the prop was balanced twice. I could not get more that the usual vibration (which always seemed to be too much) on test flights. Then, unpredictably, vibration magnitude would increase with power reduction on some later flight. I say unpredictably because I could not get increased vibration by attempting to duplicate previous conditions. Let's hope a solution surfaces at Airventure. Steve Colwell Legacy RG IO550-N with Hartzell 3 Blade -----Original Message----- From: Lancair Mailing List [mailto:_lml@lancaironline.net_ (mailto:lml@lancaironline.net) ] On Behalf Of Paul Miller Sent: Thursday, July 25, 2013 7:22 AM To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) Subject: [LML] Re: Potential Problem-Engine Vibration Ed Martin's legacy is smooth. Mine has had a lot of annoying vibes as you describe but virtually all have been removed with lots of cowling interference fixes and plug change. Many pilots forget the alternator can be a wicked source of vibration and it is almost in the same plane as the prop. The problems I had originally were in that freq range and visible at the wingtip also. Paul = --part1_8cc9b.7e9a5e70.3f26bf4e_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Craig, et al,
 
Interesting ......
 
A friend with a 600 hr, 6 cyl Continental engine switched from=20 a 2 blade to a 3 blade prop with resulting obnoxious vibration an= d,=20 after weeks of meticulously ridding the engine compartment of anything that= =20 moved from touching the fuselage or cowling, consulted a gray haired= =20 A&P who related how the wear pattern against bearings by=20 torque pulses from using a 2-blade and a 3-blade prop would = be in=20 different places in the engine.  He went back to a 2-blade prop a= nd=20 all vibration disappeared.
 
There was an example of a change affected by how the engine=20 bearing had worn that definitely resulted in inducing vibration.
 
Grayhawk
 
In a message dated 7/28/2013 1:21:29 P.M. Central Daylight Time,=20 craig@skybolt.net writes:
=
It could be possible for wear or manufacturing process to allow one = blade=20 to have more play in pitch operation than the others. 

Blue= =20 Skies,
Craig Schulze 

On Jul 27, 2013, at 5:36 PM, vtailjeff@aol.com wrote:

How is that mechanically possible? All blades are attached to the = same=20 pitch change mechanism.

J

Sent from my iPad

On Jul 27, 2013, at 12:34 PM, Steve Colwell <mcmess1919@yahoo.com>=20 wrote:

That=20 is a possibility I had not considered, I will ask Hartzell about it.&= nbsp;=20 Another possibility is the movable crankshaft counter weights failing= to=20 position correctly.

Steve Colwell 


From: Craig Schulze <craig@skybolt.net>
To: Steve Colwell <mcmess1919@yahoo.com>=20
Cc: "lml@lancaironline.net" <= lml@lancaironline.net>= =20
Sent: Friday, Jul= y 26,=20 2013 7:42 AM
Subject:<= /B> Re:=20 Potential Problem-Engine Vibration

It sounds to me that you may have an= issue=20 with your prop hub not changing the pitch exactly the  same on a= ll=20 the blades.  The vibration you are feeling is one blade taking a= =20 larger bite of air and then causing everything to wobble.  It se= ttles=20 in sometimes but when you change the power setting the pitch on the p= rop=20 is adjusted by the hub unevenly. 

Blue Skies,
Craig= =20 Schulze
Lancair N73S


On Jul 25, 2013, at 1:22 PM, "Stev= e=20 Colwell" <mcmess1919@yahoo.com>= =20 wrote:

In the first 40 hours I had vibration so severe it caus= ed=20 stick shake.  This
has continued intermittently more or less = for=20 almost 400 hours.

First I found and fixed several Cowl Interfe= rence=20 locations, then adjusted
and notched the hat section of the nose g= ear=20 door.

At about 50 hours I paid Barrett to tear down the engine= to=20 replace the
Performance pistons (prematurely worn top rings) with = stock=20 ECI pistons.
Also found a cracked case.

We had the Kelly=20 Alternator balanced and rebuilt at a shop recommended by
Bill=20 Bainbridge of B & C.  Sorry I can't remember the name, the L= egacy=20 file
is in Texas.

I rounded the leading edges of the eleva= tor=20 counter weights when building so
I temporarily squared them off to= go=20 back to the stock shape for testing.

All gear doors were check= ed in=20 flight with video camera.

The pitch trim hinge pin had play, = I=20 replaced it per Chris Zavatson's web
page.

Along the way th= e=20 prop was balanced twice.

I could not get more that the usual= =20 vibration (which always seemed to be too
much) on test flights.&nb= sp;=20 Then, unpredictably, vibration magnitude would
increase with power= =20 reduction on some later flight.  I say unpredictably
because = I=20 could not get increased vibration by attempting to duplicate
previ= ous=20 conditions.  Let's hope a solution surfaces at=20 Airventure.

Steve Colwell  Legacy RG IO550-N with Hartzel= l 3=20 Blade



-----Original Message-----
From: Lancair Mail= ing=20 List [mailto:lml@lancaironline.net] O= n=20 Behalf Of Paul
Miller
Sent: Thursday, July 25, 2013 7:22 AM
= To:=20 lml@lancaironline.netSubject:=20 [LML] Re: Potential Problem-Engine Vibration

Ed Martin's legac= y is=20 smooth.  Mine has had a lot of annoying vibes as you
describe= but=20 virtually all have been removed with lots of cowling
interference = fixes=20 and plug change.  Many pilots forget the alternator can
be a= =20 wicked source of vibration and it is almost in the same plane as=20 the
prop.

The problems I had originally were in that freq r= ange=20 and visible at the
wingtip=20 also.

Paul



=3D --part1_8cc9b.7e9a5e70.3f26bf4e_boundary--