X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [129.116.87.143] (HELO MAIL01.austin.utexas.edu) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 1036086 for flyrotary@lancaironline.net; Thu, 16 Mar 2006 10:03:33 -0500 Received-SPF: none receiver=logan.com; client-ip=129.116.87.143; envelope-from=mark.steitle@austin.utexas.edu X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C6490A.B100E892" Subject: RE: [FlyRotary] Re: Motor teardown results Date: Thu, 16 Mar 2006 09:02:48 -0600 Message-ID: <87DBA06C9A5CB84B80439BA09D86E69E040AADBC@MAIL01.austin.utexas.edu> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [FlyRotary] Re: Motor teardown results Thread-Index: AcZJCZtvmwWlIvxrRIKMUhbZFm1yuwAAPRwg From: "Mark R Steitle" To: "Rotary motors in aircraft" This is a multi-part message in MIME format. ------_=_NextPart_001_01C6490A.B100E892 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable ...and what type of oil and mix ratio have you been running? =20 Mark Steitle =20 =20 ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer Sent: Thursday, March 16, 2006 8:54 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Motor teardown results =20 Chuck, As a clarification how do you lube your apex seals ? Do you mix with fuel or=20 use injection metering pump ? =20 -- Kelly Troyer=20 Dyke Delta/13B/RD1C/EC2=20 =20 -------------- Original message from "Ed Anderson" : --------------=20 =09 =09 > Certainly, I don't feel we can rule anything out at this point, Doug.=20 > Degree of Lubrication could certainly play a role, but I personally doubt=20 > that it is the root cause - could be wrong about that, of course. I believe=20 > it may have to do with the amount of play in the rotor housing apex seal=20 > slots. I suspect that if the seals were pressing against the rotor housing=20 > wall in the manner they were designed to - the rounded top tangential to the=20 > surface of the housing - there is minimal drag and friction. As the slots=20 > wear the seals become able to "flop" from one side to the other of the=20 > housing as its chamber undergoes the 4 cycles. When "flopped" the seal's=20 > rounded top is no longer in contact as designe d and the top edge=20 > (non-rounded part) of the seal may start to drag and cause unusual wear.=20 >=20 > If lubrication was sparse and this condition existed, I think it would=20 > contribute to accelerated wear and chatter marks. But, just a hypothesis.=20 >=20 > Ed=20 >=20 > Ed Anderson=20 > Rv-6A N494BW Rotary Powered=20 > Matthews, NC=20 > eanderson@carolina.rr.com...........=20 >=20 >=20 > ----- Original Message -----=20 > From: "Doug Mueller"=20 > To: "Rotary motors in aircraft"=20 > Sent: Thursday, March 16, 2006 12:30 AM=20 > Subject: [FlyRotary] Re: Motor teardown results=20 >=20 >=20 > > Hi Chuck and Ed could there be any relationship to the lack of lubrication=20 > > to=20 > > these housings? The Lubrication increase could dampen any resonant=20 > > frequency causing chatter? What would your opinion be on that idea?=20 > > Anyone?=20 > >>=20 > >> From: "Ed Anderson"=20 > >> Date: 2006/03/16 Thu AM 12:21:11 EST=20 > >> To: "Rotary motors in aircraft"=20 > >> Subject: [FlyRotary] Re: Motor teardown results=20 > >>=20 > >> MessageThe chatter marks are certainly apparent, Chuck. Whoa! 150=20 > > hours is certainly not much out of a brand new housing. It could be as=20 > > you=20 > > suggest that the two piece seal played a role. However, I have another=20 > > suggestion. Measure the apex seal slot at the top (across the gap) and=20 > > see=20 > > what the distance is. Do it both on the good rotor and the damaged one if=20 > > you can find an undamaged spot. If like my rotor, the slots are worn, I=20 > > believe they may contribute to the chatter and breaking of the apex seal.=20 > >>=20 > >> Here's the theory. As the slot "V"s there is less support for the seal=20 > >> near=20 > > its top, the bottom is still fairly well constrained. As a consequence,=20 > > the top=20 > > portion of the seal is more able to be swayed back and forth by=20 > > combustion=20 > > and friction forces. In other words, instead of just rubbing on the rotor=20 > > housing wall with the smooth top of the seal, the edge of the seal starts=20 > > to=20 > > drag along the wall. The seal (with less support at the top) acts like a=20 > > stiff=20 > > spring (up to a limit) and "vibrates" as it slides along the housing wall=20 > > leaving=20 > > the chatter marks. At some point the forces become too much and the seal=20 > > breaks.=20 > >>=20 > >> It might be interesting to determine the vibration frequency of a seal=20 > > ( given its dimensions and composition) and then m easure the average=20 > > distance between the peaks (or valleys) of the chatter. Then given the=20 > > resonant frequency of the seal determine at what rotor rpm it would leave=20 > > chatter marks of the measured distance. {:>). No, I don't have a clue=20 > > about=20 > > how to do this, but I'll bet some mechanical engineer could come up with=20 > > something.=20 > >>=20 > >> Just a theory, of course, but if your apex slot tops are within the=20 > > specifications called for by Mazda then that would discredit the theory.=20 > > If=20 > > they are worn then it might tend to give it support.=20 > >>=20 > >>=20 > >> When my seal broke it also caught the next seal down in is slot and=20 > > smeared the top of the slot such that it could not come back up.=20 > >>=20 > >> You and I are apparently the only ones (that I know of ) that seem to=20 > >> have=20 > > had this failure mode of an apex seal disintegrating for no apparent=20 > > reason.=20 > >>=20 > >> Thanks for sharing the photos and information.=20 > >>=20 > >> Are you going to try for Sun & Fun?=20 > >>=20 > >> Ed=20 > >>=20 > >>=20 > >> Ed Anderson=20 > >> Rv-6A N494BW Rotary Powered=20 > >> Matthews, NC=20 > >> eanderson@carolina.rr.com=20 > >>=20 > >> Ed=20 > >>=20 > >>=20 > >>=20 > >> ----- Original Message -----=20 > >> From: Chuck Dunlap=20 > >> To: Rotary motors in aircraft=20 > >> Sent: Wednesday, March 15, 2006 10:44 PM=20 > >> Subject: [FlyRotary] Motor teardown results=20 > >>=20 > >>=20 > >>=20 > >>=20 > >> I finally got time to get my failed 13b apart. The rear rotor was=20 > >> missing=20 > > one apex seal, the other 2 were intact but jammed due to the fragments of=20 > > the broken one. The rotor housing has the classic chatter marks all=20 > > around.=20 > > Doing a Google of "13B apex seal chatter" results in plenty of examples of=20 > > this failure mode. Apparently the chatter is from the natural resonant=20 > > frequency of the seal, it eventually fatigues the seal causing failure.=20 > >> The front rotor was in good shape, but the housing had the same chatter=20 > > marks, but not as severe as the rear rotor. The front rotor housing was=20 > > brand=20 > > new 150 hours ago when I rebuilt this motor after the Grand Canyon forced=20 > > landing. At that time the good rotor housing had slight chatter marks but=20 > > I=20 > > reused it. The front rotor was destroyed at that time due to foreign=20 > > object=20 > & gt; entering the rotor.=20 > >> Both rotors were missing the corner seal rubber plugs on the side with=20 > > the short apex seal segment. Perhaps the small segment vibrated more,=20 > > disintegrating the rubber seals?=20 > >> The first 260 hours of flying my rotary bird was with stock 3-piece=20 > >> seals,=20 > > and I never saw any chatter marks. The last 250 hours has been flown with=20 > > 2=20 > > piece seals and now I have chatter marks .=20 > >> I now have Tracy's 2 piece apex seals and I wonder how they will=20 > >> perform,=20 > > it appears that the heavier weight of the 2 piece seals puts the resonant=20 > > frequency in the cruising range of 6000RPM?=20 > >>=20 > >> Chuck Dunlap=20 > >> RV6 13B=20 > >>=20 > >>=20 > >>=20 > > -----------------------------------------------------------------=20 > > - ------------=20 > >>=20 > >>=20 > >> --=20 > >> Homepage: http://www.flyrotary.com/=20 > >> Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/=20 > >>=20 > >>=20 > >=20 > > Doug Mueller=20 > > RX-6 13BT=20 > > N900DM=20 > > Boulder City(61B),Nevada=20 > >=20 > >=20 > > --=20 > > Homepage: http://www.flyrotary.com/=20 > > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/=20 > >=20 >=20 >=20 >=20 > --=20 > Homepage: http://www.flyrotary.com/=20 > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/=20 ------_=_NextPart_001_01C6490A.B100E892 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

…and what type of oil and mix = ratio have you been running?

 

Mark = Steitle

 

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Thursday, March 16, = 2006 8:54 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = Motor teardown results

 

Chuck,

   As a clarification how do you lube your apex = seals ? Do you mix with fuel or

use injection metering pump ?

    

--
Kelly Troyer
Dyke Delta/13B/RD1C/EC2


 

-------------- Original message from "Ed Anderson" = <eanderson@carolina.rr.com>: --------------


> Certainly, I don't feel we can rule anything out at this point, = Doug.
> Degree of Lubrication could certainly play a role, but I personally = doubt
> that it is the root cause - could be wrong about that, of course. I believe
> it may have to do with the amount of play in the rotor housing apex = seal
> slots. I suspect that if the seals were pressing against the rotor = housing
> wall in the manner they were designed to - the rounded top = tangential to the
> surface of the housing - there is minimal drag and friction. As the = slots
> wear the seals become able to "flop" from one side to the = other of the
> housing as its chamber undergoes the 4 cycles. When = "flopped" the seal's
> rounded top is no longer in contact as designe d and the top edge =
> (non-rounded part) of the seal may start to drag and cause unusual = wear.
>
> If lubrication was sparse and this condition existed, I think it = would
> contribute to accelerated wear and chatter marks. But, just a = hypothesis.
>
> Ed
>
> Ed Anderson
> Rv-6A N494BW Rotary Powered
> Matthews, NC
> eanderson@carolina.rr.com...........
>
>
> ----- Original Message -----
> From: "Doug Mueller"
> To: "Rotary motors in aircraft"
> Sent: Thursday, March 16, 2006 12:30 = AM
> Subject: [FlyRotary] Re: Motor teardown results
>
>
> > Hi Chuck and Ed could there be any relationship to the lack of lubrication
> > to
> > these housings? The Lubrication increase could dampen any = resonant
> > frequency causing chatter? What would your opinion be on that = idea?
> > Anyone?
> >>
> >> From: "Ed Anderson"
> >> Date: 2006/03/16 Thu AM = 12:21:11 EST
> >> To: "Rotary motors in aircraft"
> >> Subject: [FlyRotary] Re: = Motor teardown results
> >>
> >> MessageThe chatter marks are certainly apparent, Chuck. = Whoa! 150
> > hours is certainly not much out of a brand new housing. It = could be as
> > you
> > suggest that the two piece seal played a role. However, I have another
> > suggestion. Measure the apex seal slot at the top (across the = gap) and
> > see
> > what the distance is. Do it both on the good rotor and the = damaged one if
> > you can find an undamaged spot. If like my rotor, the slots = are worn, I
> > believe they may contribute to the chatter and breaking of the = apex seal.
> >>
> >> Here's the theory. As the slot "V"s there is = less support for the seal
> >> near
> > its top, the bottom is still fairly well constrained. As a consequence,
> > the top
> > portion of the seal is more able to be swayed back and forth = by
> > combustion
> > and friction forces. In other words, instead of just rubbing = on the rotor
> > housing wall with the smooth top of the seal, the edge of the = seal starts
> > to
> > drag along the wall. The seal (with less support at the top) = acts like a
> > stiff
> > spring (up to a limit) and "vibrates" as it slides = along the housing wall
> > leaving
> > the chatter marks. At some point the forces become too much = and the seal
> > breaks.
> >>
> >> It might be interesting to determine the vibration = frequency of a seal
> > ( given its dimensions and composition) and then m easure the = average
> > distance between the peaks (or valleys) of the chatter. Then = given the
> > resonant frequency of the seal determine at what rotor rpm it = would leave
> > chatter marks of the measured distance. {:>). No, I don't = have a clue
> > about
> > how to do this, but I'll bet some mechanical engineer could = come up with
> > something.
> >>
> >> Just a theory, of course, but if your apex slot tops are = within the
> > specifications called for by Mazda then that would discredit = the theory.
> > If
> > they are worn then it might tend to give it support.
> >>
> >>
> >> When my seal broke it also caught the next seal down in is = slot and
> > smeared the top of the slot such that it could not come back = up.
> >>
> >> You and I are apparently the only ones (that I know of ) = that seem to
> >> have
> > had this failure mode of an apex seal disintegrating for no = apparent
> > reason.
> >>
> >> Thanks for sharing the photos and information.
> >>
> >> Are you going to try for Sun & Fun?
> >>
> >> Ed
> >>
> >>
> >> Ed Anderson
> >> Rv-6A N494BW Rotary Powered
> >> Matthews, NC
> >> eanderson@carolina.rr.com
> >>
> >> Ed
> >>
> >>
> >>
> >> ----- Original Message -----
> >> From: Chuck Dunlap
> >> To: Rotary motors in aircraft
> >> Sent: Wednesday, March 15, 2006 10:44 PM
> >> Subject: [FlyRotary] Motor teardown results
> >>
> >>
> >>
> >>
> >> I finally got time to get my failed 13b apart. The rear = rotor was
> >> missing
> > one apex seal, the other 2 were intact but jammed due to the fragments of
> > the broken one. The rotor housing has the classic chatter = marks all
> > around.
> > Doing a Google of "13B apex seal chatter" results in = plenty of examples of
> > this failure mode. Apparently the chatter is from the natural resonant
> > frequency of the seal, it eventually fatigues the seal causing failure.
> >> The front rotor was in good shape, but the housing had the = same chatter
> > marks, but not as severe as the rear rotor. The front rotor = housing was
> > brand
> > new 150 hours ago when I rebuilt this motor after the = Grand Canyon forced
> > landing. At that time the good rotor housing had slight = chatter marks but
> > I
> > reused it. The front rotor was destroyed at that time due to = foreign
> > object
> & gt; entering the rotor.
> >> Both rotors were missing the corner seal rubber plugs on = the side with
> > the short apex seal segment. Perhaps the small segment = vibrated more,
> > disintegrating the rubber seals?
> >> The first 260 hours of flying my rotary bird was with = stock 3-piece
> >> seals,
> > and I never saw any chatter marks. The last 250 hours has been = flown with
> > 2
> > piece seals and now I have chatter marks .
> >> I now have Tracy's 2 piece apex seals and I wonder how they will
> >> perform,
> > it appears that the heavier weight of the 2 piece seals puts = the resonant
> > frequency in the cruising range of 6000RPM?
> >>
> >> Chuck Dunlap
> >> RV6 13B
> >>
> >>
> >>
> > = -----------------------------------------------------------------
> > - ------------
> >>
> >>
> >> --
> >> Homepage: http://www.flyrotary.com/
> >> Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/
> >>
> >>
> >
> > Doug Mueller
> > RX-6 13BT
> > N900DM
> > Boulder City(61B),Nevada
> >
> >
> > --
> > Homepage: http://www.flyrotary.com/
> > Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/
> >
>
>
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ =

------_=_NextPart_001_01C6490A.B100E892--