X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David COOK hoursaway1@comcast.net" Received: from pmg.Logan.com ([207.170.160.161] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 3782725 for flyrotary@lancaironline.net; Fri, 10 Jan 2025 06:00:36 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id 919A428EC9 for ; Fri, 10 Jan 2025 06:00:36 -0500 (EST) Received-SPF: pass (comcast.net: 96.103.146.52 is authorized to use 'hoursaway1@comcast.net' in 'mfrom' identity (mechanism 'ip4:96.103.146.48/28' matched)) receiver=pmg.Logan.com; identity=mailfrom; envelope-from="hoursaway1@comcast.net"; helo=resqmta-a2p-658918.sys.comcast.net; client-ip=96.103.146.52 Received: from resqmta-a2p-658918.sys.comcast.net (resqmta-a2p-658918.sys.comcast.net [96.103.146.52]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Fri, 10 Jan 2025 06:00:34 -0500 (EST) Received: from resomta-a2p-646966.sys.comcast.net ([96.103.145.238]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 256/256 bits) (Client did not present a certificate) by resqmta-a2p-658918.sys.comcast.net with ESMTPS id WCG7tz4Mo7ZeuWCketIAdB; Fri, 10 Jan 2025 11:00:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1736506828; bh=ocJkVODI0jl/QnhbtCpY4KMQb9K1kmf4+bi6v1eQ/x4=; h=Received:Received:Date:From:To:Message-ID:Subject:MIME-Version: Content-Type:Xfinity-Spam-Result; b=iAGBDrYiNjIe8t/ywqAeoUNPA/ya1oemnoo9+ANH04PuVuNknms4kSQ7QLc46VXSx 13Gb5Fuz9e61kSSnyHFK+3zfWhvJEeovxepNOBKZssci8n0aJU8tS/QzTuAcbBtAxl nQBzZPYetytRoa6FtdRoXQRD6VIve2lkVfqCM4xz1oQCAxjyoSgzW2xHF8ffqh9HZK bFTT6IfLaApxTgbjnxpUrSn6ksPpwLBFe1sztxSNbIBkx2BvmcsnAOjMgqIPK9CGSq Sbn5hYooPoCv18dZ0qtZTL+ic+kX9D01yyHhYVArhDmWBM3BvDtdbGjLhm3CCpwaUQ XJTsrBmamdT8w== Received: from oxapp-ch2g-48o.email.comcast.net ([96.118.136.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 256/256 bits) (Client did not present a certificate) by resomta-a2p-646966.sys.comcast.net with ESMTPS id WCkdtVLl32CqbWCkdtcSnA; Fri, 10 Jan 2025 11:00:28 +0000 Date: Fri, 10 Jan 2025 06:00:27 -0500 (EST) To: Rotary motors in aircraft Message-ID: <38439216.1415224.1736506827484@connect.xfinity.com> In-Reply-To: References: Subject: Re: [FlyRotary] Re: Flexplate cracks MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_1415223_1101499027.1736506827429" X-Priority: 3 Importance: Normal X-Mailer: Open-Xchange Mailer v7.10.6-Rev59 X-Originating-IP: ::ffff:136.226.108.119 X-Originating-Client: open-xchange-appsuite X-CMAE-Envelope: MS4xfDWx1r0lwuerF0oXEBsbn+1z/GObDebhnFrWM3RCAxHtyeNAO7kCQkjTcMqZwYdHCmauFMFzw19oLevQ+BSjWRXQBXcxVd+4I621cdXu9S6cS+PImGRJ GZyobQkbfBLRPniT4uC0LMNeHQzNBHpe8rK/gqDXsJLSirSdkvI0/HiHWNObO0fmrCaAaXngzNdJBcVP4wjCBMb5SoQ39KI/3uqWX/z5Pjpe6sztO0I6KGxI X-SPAM-LEVEL: Spam detection results: 0 AWL 0.250 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DKIM_SIGNED 0.1 Message has a DKIM or DK signature, not necessarily valid DKIM_VALID -0.1 Message has at least one valid DKIM or DK signature DKIM_VALID_AU -0.1 Message has a valid DKIM or DK signature from author's domain DKIM_VALID_EF -0.1 Message has a valid DKIM or DK signature from envelope-from domain DMARC_PASS -0.1 DMARC pass policy FREEMAIL_ENVFROM_END_DIGIT 0.25 Envelope-from freemail username ends in digit FREEMAIL_FROM 0.001 Sender email is commonly abused enduser mail provider HTML_MESSAGE 0.001 HTML included in message KAM_MXURI 1.5 URI begins with a mail exchange prefix, i.e. mx.[...] RCVD_IN_DNSWL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to DNSWL was blocked. 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[lancaironline.net,flyrotary.com] WEIRD_PORT 0.001 Uses non-standard port number for HTTP ------=_Part_1415223_1101499027.1736506827429 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Automotive tech for 40 years, 25 years Cadillac. I saw quite a few cracked = flexplates. Why, some were self diagnosed, corrosion between starter and en= g. block changed geometry, witness marks that cust. would try to start a ru= nning eng., loose torque converter bolts, loose trans to eng. bolts, wrong = starter held on with one bolt. When I was seeking a Mazda RX7 flexplate for= out project, first three were cracked right out of the cars. I think our s= tarter is shimmed out 1/16", original RWS PSRU-RD1-B, original starter posi= tion.=20 =20 > On 01/10/2025 4:44 AM EST Le Roux Breytenbach breytenbachleroux@gmail.com= wrote: > =20 > =20 > What i can rember was this also a topic on the late Paul L group discussi= on. > Maybe Dave Leonard can chime in - think more that it was gyroscopic force= s that craked the plates > Maybe i can find the photos and topic in my old mails >=20 > Sent from my iPhone > Le Roux Breytenbach=20 >=20 >=20 > > On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au wrote: > >=20 > >=20 >=20 > > Maybe some of the cracking flexplates are resulting from starting issue= s, the starter motor can hammer the ring gear if not meshing correctly or i= f engine misfires on start. may explain why so many flexplates come pre-cra= cked from the wreckers. > > =20 > > Andrew > >=20 > >=20 > >=20 > >=20 > > On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com mai= lto:stephen.izett@gmail.com wrote: > >=20 > > > Hi M > > >=20 > > > I was wondering the same thing. > > >=20 > > > What I discovered first of all was that flex plates are designed to f= lex (funny that) and cracking is not limited to our setup. > > > There are companies that specialise in stronger flex plates, particul= arly for modified and higher horsepower engines. > > >=20 > > > Since our engines are being used at a higher horsepower per unit time= and therefore higher stress (assumption) perhaps our setup could be likene= d to race applications. > > > But then our hours of use would be significantly lower (assumption) t= han an average vehicle, but perhaps not a race application. > > > Is the cracking we are seeing consistent with race applications? But = they dont race automatics, do they? > > >=20 > > > So my take on this is that perhaps the flexing of the plate in our se= tup is to some extent higher than OEM. > > >=20 > > > Our options seem to be: > > > 1. Replacing the OEM flex plate with a stronger part. Steve B being t= he latest going down that track and in his case also removing the rubber is= olation in the process. > > > 2. Connect direct to the eccentric shaft and therefore taking the str= ess off the Flex Plate doing away with the damping mechanism which Tracy di= d, and perhaps is still doing. Would be real nice to know. > > >=20 > > > Like M, I would appreciate hearing what others know or are thinking o= r doing. > > >=20 > > > Steve Izett > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > >=20 > > > > On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese cardmarc@charter.net= mailto:cardmarc@charter.net wrote: > > > > > > > > Has the cause of these cracks been uncovered, and if so, what is th= e current thinking on it? An AL racing plate? > > > > M > > > > Sent from my iPhone > > > > > > > >> On Jan 9, 2025, at 1:31=E2=80=AFAM, Steven W. Boese SBoese@uwyo.ed= u mailto:SBoese@uwyo.edu wrote: > > > >> > > > >> Steve, > > > >> > > > >> I didn=E2=80=99t see the cracks prior to disassembly and doubt tha= t they could have been seen on the counterweight side very well -if at all-= when assembled. > > > >> > > > >> I replaced the Flexplate with a steel flywheel about a year ago. = Since then, I replaced the four rubber dampers with machined aluminum discs= giving a solid connection and then dynamically balanced the system. This = was done because maintaining a dynamic balance wasn=E2=80=99t possible with= the dampers. Only a few hours of flight have occurred in this configurati= on so far and there has been no indication of problems resulting from this = change. > > > >> > > > >> Steve Boese > > > >> > > > >>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett stephen.izett@= gmail.com mailto:stephen.izett@gmail.com wrote: > > > >>> > > > >>> =E2=97=86 This message was sent from a non-UWYO address. Please e= xercise caution when clicking links or opening attachments from external so= urces. > > > >>> > > > >>> > > > >>> Hi Steve > > > >>> > > > >>> Is this recent then? > > > >>> > > > >>> I=E2=80=99m not able to get to my aircraft at present to check my= flex plate which has probably seen 50 hours of service. > > > >>> > > > >>> Was it possible to see these cracks assembled? > > > >>> > > > >>> I would appreciate your reflections on Tracys latter choice to re= move the damper, and particularly when using a timber/glass prop such as an= MT. > > > >>> > > > >>> It would be great to have an update and current info from Tracy r= egarding his no damper hours if anyone can contact him. > > > >>> > > > >>> Very helpful, thanks again Steve > > > >>> > > > >>> Steve > > > >> > > > >> -- > > > >> Homepage: http://www.flyrotary.com/ > > > >> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrot= ary/List.html > > > > > > > > > > > > > > > > -- > > > > Homepage: http://www.flyrotary.com/ > > > > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrota= ry/List.html > > >=20 > > >=20 > > >=20 > > > -- > > > Homepage: http://www.flyrotary.com/ > > > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary= /List.html > > >=20 > >=20 >=20 ------=_Part_1415223_1101499027.1736506827429 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =20 =20
Automotive tech= for 40 years, 25 years Cadillac. I saw quite a few cracked flexplates. Why= , some were self diagnosed, corrosion between starter and eng. block change= d geometry, witness marks that cust. would try to start a running eng., loo= se torque converter bolts, loose trans to eng. bolts, wrong starter held on= with one bolt. When I was seeking a Mazda RX7 flexplate for out project, f= irst three were cracked right out of the cars. I think our starter is shimm= ed out 1/16", original RWS PSRU-RD1-B, original starter position. 
=20
 
=20
=20
On 01/10/2025 4:44 AM EST Le Roux Breytenbach breytenbachleroux@gmail.c= om <flyrotary@lancaironline.net> wrote:
=20
 
=20
 
What i can rember was this also a topic on the late Paul L group = discussion.=20
Maybe Dave Leonard can chime in - think more that it was gyroscopic for= ces that craked the plates
=20
Maybe i can find the photos and topic in my old mails
=20

=20
Sent from my iPhone=20
Le Roux Breytenbach 
=20
=20

=20
On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au <fl= yrotary@lancaironline.net> wrote:

=20
=20
=20
=20
=20
Maybe some of the cracking flexplates are resulting from starting i= ssues, the starter motor can hammer the ring gear if not meshing correctly = or if engine misfires on start. may explain why so many flexplates come pre= -cracked from the wreckers.
=20
 
=20
Andrew
=20
=20
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=20



=20
=20
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On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
=20
Hi M

I was wondering the same thing.=20

What I discovered first of all was that flex plates are designe= d to flex (funny that) and cracking is not limited to our setup.=20
There are companies that specialise in stronger flex plates, pa= rticularly for modified and higher horsepower engines.

Since our engines are being used at a higher horsepower per uni= t time and therefore higher stress (assumption) perhaps our setup could be = likened to race applications.
But then our hours of use would be significantly lower (assumpt= ion) than an average vehicle, but perhaps not a race application.
Is the cracking we are seeing consistent with race applications= ? But they dont race automatics, do they?

So my take on this is that perhaps the flexing of the plate in = our setup is to some extent higher than OEM.

Our options seem to be:
1. Replacing the OEM flex plate with a stronger part. Steve B b= eing the latest going down that track and in his case also removing the rub= ber isolation in the process.
2. Connect direct to the eccentric shaft and therefore taking t= he stress off the Flex Plate doing away with the damping mechanism which Tr= acy did, and perhaps is still doing. Would be real nice to know.

Like M, I would appreciate hearing what others know or are thin= king or doing.

Steve Izett












> On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese cardmarc@ch= arter.net <flyrotary@lancaironline.net> wrote:
>=20
> Has the cause of these cracks been uncovered, and if so, w= hat is the current thinking on it? An AL racing plate?
> M
> Sent from my iPhone
>=20
>> On Jan 9, 2025, at 1:31=E2=80=AFAM, Steven W. Boese SBoese@= uwyo.edu <flyrotary@lancaironline.net> wrote:
>>=20
>> Steve,
>>=20
>> I didn=E2=80=99t see the cracks prior to disassembly a= nd doubt that they could have been seen on the counterweight side very well= -if at all- when assembled.
>>=20
>> I replaced the Flexplate with a steel flywheel about a= year ago.  Since then, I replaced the four rubber dampers with machin= ed aluminum discs giving a solid connection and then dynamically balanced t= he system.  This was done because maintaining a dynamic balance wasn= =E2=80=99t possible with the dampers.  Only a few hours of flight have= occurred in this configuration so far and there has been no indication of = problems resulting from this change.
>>=20
>> Steve Boese
>>=20
>>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett= stephen.izett@gmail.com <flyrotary@lancaironline.net&= gt; wrote:
>>>=20
>>> =E2=97=86 This message was sent from a non-UWYO ad= dress. Please exercise caution when clicking links or opening attachments f= rom external sources.
>>>=20
>>>=20
>>> Hi Steve
>>>=20
>>> Is this recent then?
>>>=20
>>> I=E2=80=99m not able to get to my aircraft at pres= ent to check my flex plate which has probably seen 50 hours of service.
>>>=20
>>> Was it possible to see these cracks assembled?
>>>=20
>>> I would appreciate your reflections on Tracys latt= er choice to remove the damper, and particularly when using a timber/glass = prop such as an MT.
>>>=20
>>> It would be great to have an update and current in= fo from Tracy regarding his no damper hours if anyone can contact him.
>>>=20
>>> Very helpful, thanks again Steve
>>>=20
>>> Steve
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html
>=20
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html



--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   h= ttp://mail.lancaironline.net:81/lists/flyrotary/List.html
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