X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 28 Jul 2013 21:54:22 -0400 Message-ID: X-Original-Return-Path: Received: from [208.113.200.5] (HELO homiemail-a44.g.dreamhost.com) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTP id 6394391 for lml@lancaironline.net; Sun, 28 Jul 2013 19:30:29 -0400 Received-SPF: none receiver=logan.com; client-ip=208.113.200.5; envelope-from=r.rickard@rcginc-us.com Received: from homiemail-a44.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a44.g.dreamhost.com (Postfix) with ESMTP id 2109311805C for ; Sun, 28 Jul 2013 16:29:54 -0700 (PDT) Received: from [192.168.1.104] (24-107-103-44.dhcp.stls.mo.charter.com [24.107.103.44]) (Authenticated sender: r.rickard@rcginc-us.com) by homiemail-a44.g.dreamhost.com (Postfix) with ESMTPA id B0DC9118057 for ; Sun, 28 Jul 2013 16:29:53 -0700 (PDT) Subject: Re: [LML] Re: Potential Problem-Engine Vibration References: From: Bob Rickard Content-Type: multipart/alternative; boundary=Apple-Mail-7C7B7190-D3C5-4E4A-A5FD-A4791A2E085C X-Mailer: iPad Mail (10B329) In-Reply-To: X-Original-Message-Id: <9BE4CC4D-27CD-47A1-AF7A-962DE22CCDF5@rcginc-us.com> X-Original-Date: Sun, 28 Jul 2013 18:29:52 -0500 X-Original-To: Lancair Mailing List Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-7C7B7190-D3C5-4E4A-A5FD-A4791A2E085C Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Gents Lets clarify a bit. We are NOT talking about a typical persistent vibration= . It is not a case of interference with the cowl or anything else like that= . There are 4 reasons I state this: 1. Previous 3 blade prop did not have this phenomenon in my own installatio= n (Aerocomposites 3 blade), and doesn't seem to be present on any 4 blade in= stallations or any non-Hartzell props. Vibration problems sorted over 1250 h= ours TT before changing to Hartzell prop (by Jeff Edwards - this was his pla= ne before I bought it!). 2. Vibration amplitude changes over time with no power changes (such as in c= ruise) - not typical for interference issues... 3. Vibration AMPLITUDE changes with a change in RPM. This data point got p= rop shop and mechanic very worried, which led me to a new prop and the test o= f the crank - thank God. 4. Vibration phenomenon was persistent before and after a complete overhaul= (by Barrett in Tulsa). And magnaflux/ultrasound of crank at overhaul show= ed no problem. This rules out any crank weight problems or misfiring, etc. = =20 So its incorrect to lump this phenomenon in with all of the other normal vib= ration issues we deal with as a community. With very few (known) exceptions= , this seems to be localized to big bore continental engines paired with 76"= (or 78") Hartzell 3 blade newer scimitar props. There are certainly those o= ut there with this combination that do not have this problem, but there are m= any of us that do have it and cannot fix it by any known means - short of ch= anging the prop. So I wouldn't rule out a compatibility problem, a prop des= ign problem, a crank flange problem, or something we have not thought of yet= . =20 The most important thing is for those of us who have this problem to check f= or cracks in the prop flange asap. If found, fix and document so we don't l= ose another prop in flight (or worse). In the meantime we will collect data= and see where it leads us. Bob R On Jul 28, 2013, at 2:29 PM, Paul Miller wrote: > Agreed, I wouldn't have the nerve to pitch that to hartzell and mr brown. = They are not fly by nights at hartzell. The issue is whether a common pro= blem exists. I think Hartzell system wide manufacturing defect can be safel= y moved to low priority. Hartzell does a thorough vibration analysis on engi= ne prop combinations so I don't see how something new cropped up there. >=20 > Lyc had the crankshaft issue on the Malibu, I don't recall it being relate= d to prop at all. >=20 > I think it is a mistake to look for hartzell 550 combination as being a fa= ctor in vibration since the sample is largely hartzell and 550. You need so= me other way to differentiate between vibrating and non vibrating installati= ons. I can safely say that if I found 20 contact points in the legacy over t= he last four years I would be cataloging those points first and confirming t= hey are not in play. Once those are ruled out then you have something to w= ork with. A database of 550s with and without problems may not go very far= to getting a resolution. >=20 > Paul >=20 > On 2013-07-28, at 14:37, "Danny" wrote: >=20 >> WHAT? That makes no sense at all. Where did you ever get such an idea? >> =20 >> Danny >> LNC2-360 Mk-II >> Nothing is foolproof to the sufficiently talented fool. >> =20 >> From: Craig Schulze [mailto:craig@skybolt.net]=20 >> Sent: Sunday, July 28, 2013 2:21 PM >> To: lml@lancaironline.net >> Subject: [LML] Re: Potential Problem-Engine Vibration >> =20 >> It could be possible for wear or manufacturing process to allow one blade= to have more play in pitch operation than the others.=20 >>=20 >> Blue Skies, >> Craig Schulze=20 >>=20 >> On Jul 27, 2013, at 5:36 PM, vtailjeff@aol.com wrote: >>=20 >> How is that mechanically possible? All blades are attached to the same pi= tch change mechanisms Elton=20 >> =20 >> J >>=20 >> Sent from my iPad >>=20 >> On Jul 27, 2013, at 12:34 PM, Steve Colwell wrote:= >>=20 >> That is a possibility I had not considered, I will ask Hartzell about it.= Another possibility is the movable crankshaft counter weights failing to p= osition correctly. >>=20 >> Steve Colwell=20 >> =20 >> =20 >> From: Craig Schulze >> To: Steve Colwell =20 >> Cc: "lml@lancaironline.net" =20 >> Sent: Friday, July 26, 2013 7:42 AM >> Subject: Re: Potential Problem-Engine Vibration >>=20 >> It sounds to me that you may have an issue with your prop hub not changin= g the pitch exactly the same on all the blades. The vibration you are feel= ing is one blade taking a larger bite of air and then causing everything to w= obble. It settles in sometimes but when you change the power setting the pi= tch on the prop is adjusted by the hub unevenly. =20 >>=20 >> Blue Skies, >> Craig Schulze >> Lancair N73S >>=20 >>=20 >> On Jul 25, 2013, at 1:22 PM, "Steve Colwell" wrote= : >>=20 >> In the first 40 hours I had vibration so severe it caused stick shake. T= his >> has continued intermittently more or less for almost 400 hours. >>=20 >> First I found and fixed several Cowl Interference locations, then adjuste= d >> and notched the hat section of the nose gear door. >>=20 >> 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. >>=20 >> 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 fi= le >> is in Texas.=20 >>=20 >> 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.= >>=20 >> All gear doors were checked in flight with video camera.=20 >>=20 >> The pitch trim hinge pin had play, I replaced it per Chris Zavatson's web= >> page. >>=20 >> Along the way the prop was balanced twice. >>=20 >> I could not get more that the usual vibration (which always seemed to be t= oo >> 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. >>=20 >> Steve Colwell Legacy RG IO550-N with Hartzell 3 Blade >>=20 >>=20 >>=20 >> -----Original Message----- >> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Pa= ul >> Miller >> Sent: Thursday, July 25, 2013 7:22 AM >> To: lml@lancaironline.net >> Subject: [LML] Re: Potential Problem-Engine Vibration >>=20 >> Ed Martin's legacy is smooth. Mine has had a lot of annoying vibes as yo= u >> describe but virtually all have been removed with lots of cowling >> interference fixes and plug change. Many pilots forget the alternator ca= n >> be a wicked source of vibration and it is almost in the same plane as the= >> prop. >>=20 >> The problems I had originally were in that freq range and visible at the >> wingtip also. >>=20 >> Paul >>=20 >>=20 --Apple-Mail-7C7B7190-D3C5-4E4A-A5FD-A4791A2E085C Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Gents

Lets cl= arify a bit.  We are NOT talking about a typical persistent vibration. &= nbsp;It is not a case of interference with the cowl or anything else like th= at.  There are 4 reasons I state this:

1. &nbs= p;Previous 3 blade prop did not have this phenomenon in my own installation (= Aerocomposites 3 blade), and doesn't seem to be present on any 4 blade insta= llations or any non-Hartzell props.  Vibration problems sorted over 125= 0 hours TT before changing to Hartzell prop (by Jeff Edwards - this was his p= lane before I bought it!).
2.  Vibration amplitude changes ov= er time with no power changes (such as in cruise) - not typical for interfer= ence issues...
3.  Vibration AMPLITUDE changes with a change i= n RPM.  This  data point got prop shop and mechanic very worried, w= hich led me to a new prop and the test of the crank - thank God.
4= .  Vibration phenomenon was persistent before and after a complete over= haul (by Barrett in Tulsa).   And magnaflux/ultrasound of crank at over= haul showed no problem.  This rules out any crank weight problems or mi= sfiring, etc.  

So its incorrect to lump this p= henomenon in with all of the other normal vibration issues we deal with as a= community.  With very few (known) exceptions, this seems to be localiz= ed to big bore continental engines paired with 76" (or 78") Hartzell 3 blade= newer scimitar props.  There are certainly those out there with this c= ombination that do not have this problem, but there are many of us that do h= ave it and cannot fix it by any known means - short of changing the prop. &n= bsp;So I wouldn't rule out a compatibility problem, a prop design problem, a= crank flange problem, or something we have not thought of yet.  
=

The most important thing is for those of us who have thi= s problem to check for cracks in the prop flange asap.  If found, fix a= nd document so we don't lose another prop in flight (or worse).  In the= meantime we will collect data and see where it leads us.

Bob R

On Jul 28, 2013, at 2:29 PM, Paul Miller <pjdmiller@gmail.com> wrote:
Agreed, I wouldn't have the nerve to= pitch that to hartzell and mr brown.  They are not fly by nights at ha= rtzell.   The issue is whether a common problem exists.  I think H= artzell system wide manufacturing defect can be safely moved to low priority= . Hartzell does a thorough vibration analysis on engine prop combinations so= I don't see how something new cropped up there.

Ly= c had the crankshaft issue on the Malibu, I don't recall it being related to= prop at all.

I think it is a mistake to look for h= artzell 550 combination as being a factor in vibration since the sample is l= argely hartzell and 550.  You need some other way to differentiate betw= een vibrating and non vibrating installations.  I can safely say that i= f I found 20 contact points in the legacy over the last four years I would b= e cataloging those points first and confirming they are not in play.   O= nce those are ruled out then you have something to work with.   A datab= ase of 550s with and without problems may not go very far to getting a resol= ution.

Paul

On 2013-07-28, at 14:37, "Danny" <danny@n107sd.com> wrote:

<= blockquote type=3D"cite">

WHAT?  That makes no sense at al= l.  Where did you ever get such an idea?

 

<= p class=3D"MsoNormal">Danny<= /p>

LNC2-360 Mk-II<= /o:p>

Nothing= is foolproof to the sufficiently talented fool.

=

 

From: Craig Schulze [mailto:craig@skyb= olt.net]
Sent: Sunday, July 28, 2013 2:21 PM
To: lml@lancaironline.net
Subje= ct: [LML] Re: Potential Problem-Engine Vibration

 

It could be possible for wear or manufacturing process to allow one bl= ade to have more play in pitch operation than the others. 

Blue S= kies,

Craig Schulze 


On Jul 27, 2013, at 5:36 PM, vtail= jeff@aol.com wrote:

How is that mech= anically possible? All blades are attached to the same pitch change mechanis= ms Elton 

 

J

Sent from my iPad


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

That is a pos= sibility I had not considered, I will ask Hartzell about it.  Another p= ossibility is the movable crankshaft counter weights failing to position cor= rectly.

Steve Colwell 

 <= /o:p>

 

<= b>From: Craig Schulze= <craig@skybolt.net>
To= : Steve Colwell <mcmess1919@y= ahoo.com>
Cc: "lm= l@lancaironline.net" <lml@la= ncaironline.net>
Sent: Friday, July 26, 2013 7:42 AM
Subject: Re: Potential Problem-Engine Vibration


It so= unds to me that you may have an issue with your prop hub not changing the pi= tch exactly the  same on all the blades.  The vibration you are fe= eling is one blade taking a larger bite of air and then causing everything t= o wobble.  It settles in sometimes but when you change the power settin= g the pitch on the prop is adjusted by the hub unevenly. 

Blue S= kies,
Craig Schulze
Lancair N73S


On Jul 25, 2013, at 1:22 P= M, "Steve Colwell" <mcmess1919@ya= hoo.com> wrote:

In the first 40 hours I had vibration so sever= e it caused stick shake.  This
has continued intermittently more or l= ess for almost 400 hours.

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

At about 50 hours I paid Barrett to tear down the engine to= replace the
Performance pistons (prematurely worn top rings) with stock E= CI 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. <= br>
I rounded the leading edges of the elevator counter weights when buil= ding so
I temporarily squared them off to go back to the stock shape for t= esting.

All gear doors were checked in flight with video camera.
=
The pitch trim hinge pin had play, I replaced it per Chris Zavatson's we= b
page.

Along the way the prop was balanced twice.

I could n= ot get more that the usual vibration (which always seemed to be too
much)= on test flights.  Then, unpredictably, vibration magnitude would
in= crease with power reduction on some later flight.  I say unpredictably<= br>because I could not get increased vibration by attempting to duplicateprevious 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] On Behalf Of Pa= ul
Miller
Sent: Thursday, July 25, 2013 7:22 AM
To: lml@lancaironline.net
Subject: [LML] Re: Po= tential Problem-Engine Vibration

Ed Martin's legacy is smooth.  M= ine has had a lot of annoying vibes as you
describe but virtually all hav= e been removed with lots of cowling
interference fixes and plug change.&n= bsp; Many pilots forget the alternator can
be a wicked source of vibratio= n and it is almost in the same plane as the
prop.

The problems I h= ad originally were in that freq range and visible at the
wingtip also.
Paul


= --Apple-Mail-7C7B7190-D3C5-4E4A-A5FD-A4791A2E085C--