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 3784707 for flyrotary@lancaironline.net; Sat, 11 Jan 2025 11:38:34 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id DE76730C5D for ; Sat, 11 Jan 2025 11:38:33 -0500 (EST) Received-SPF: pass (comcast.net: 96.103.146.60 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=resdmta-a2p-658199.sys.comcast.net; client-ip=96.103.146.60 Received: from resdmta-a2p-658199.sys.comcast.net (resdmta-a2p-658199.sys.comcast.net [96.103.146.60]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Sat, 11 Jan 2025 11:38:33 -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 resdmta-a2p-658199.sys.comcast.net with ESMTPS id We0ptvMW5r283WeVFtnOtb; Sat, 11 Jan 2025 16:38:25 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1736613505; bh=70u0zDudwGtAEHlaB/v5aXd6wwnnB7+Z7OnpdrvZATg=; h=Received:Received:Date:From:To:Message-ID:Subject:MIME-Version: Content-Type:Xfinity-Spam-Result; b=Dcu+OmQBkWoNcZ5IwIoAhPz1hHe0I87csLkA/tnolMOUodgml3lsTb+Kk+8LC84Cm UnrUZbZZvPEGTHCyqEAOJn6EmADmYJ690EgM4Vw031UoXlDX3PB3EHfs4rdGmoNjrG 45/Sy7kxuyJVwmn+4F4Yv7rsfWHOdk1bIeeNskFoEk8eyALtMa+5ZLwOGzZBJuSxVL 5Wy+Fr8OtAlzvcNADaG+TfsUM9DD6ep5fEmCtD4Mex705MKXfBDBkYYqEHnQ/XBhNZ wWkT9zxbTePXhHSey+WcZMrG5/CB9wxNKmQmV2c8mFnov/501w0KkzMSgipj7LXUmD qQkxmeggT49ug== Received: from oxapp-ch2f-15o.email.comcast.net ([96.117.87.37]) (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 WeVFtd1RU2CqbWeVFtfCUg; Sat, 11 Jan 2025 16:38:25 +0000 Date: Sat, 11 Jan 2025 11:38:25 -0500 (EST) To: Rotary motors in aircraft Message-ID: <1658377272.1223709.1736613505306@connect.xfinity.com> In-Reply-To: References: Subject: Re: [FlyRotary] Re: Flexplate cracks MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_1223708_490891432.1736613505276" X-Priority: 3 Importance: Normal X-Mailer: Open-Xchange Mailer v7.10.6-Rev59 X-Originating-IP: 2601:405:4980:5fe0:4464:1e46:12a4:663e X-Originating-Client: open-xchange-appsuite X-CMAE-Envelope: MS4xfK+g1F/sgSxL3dWpkW6bmlrecKHs8OoKosWKK12Y+P/H2cFbbERTIR+QOnnhn7O3T+RvcATtSaF16iYUWjwMKWxTS8b9JfpKxGvjTFWUj5vWPjr58C8y DH0CWDMQqtDJOKnwlEkO+hY4NpNwel/WDt9+88+CCjaOgvaX2amYM4VxuDcBHZEuPVcBcmJQZjnuUCJS3icqLj0CfUm8MJt2HMeKgeiEk1IjzCTBtIPBQ5C5 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.040 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.[...] SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record WEIRD_PORT 0.001 Uses non-standard port number for HTTP ------=_Part_1223708_490891432.1736613505276 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I personally removed two eng. from the RX7's, heard them start and run, dro= ve one, both had cracks in flex plates. David > On 01/10/2025 11:50 PM EST Charlie England ceengland7@gmail.com wrote: > =20 > =20 > They do crack in the car, regardless. >=20 > On Fri, Jan 10, 2025 at 10:36=E2=80=AFPM Stephen Izett stephen.izett@gmai= l.com mailto:stephen.izett@gmail.com wrote: >=20 > > Hi there Dave > > =20 > > I understood the torque converter was driven from the flex plate.=20 > > Can someone confirm how power is transferred from the Eccentric to the = torque converter? > > =20 > > Steve Izett > >=20 > >=20 > > > On 11 Jan 2025, at 9:35=E2=80=AFam, David Leonard wdleonard@gmail.com= mailto:wdleonard@gmail.com wrote: > > >=20 > > > in the car, the flex plates are only used to carry the torque from th= e starter and are not designed to transmit the output of the engine. in our= setups. We have adapted this flex plate to transmit the entire output of t= he engine which it apparently is not up to.=20 > > > =20 > > > I had my rd1-b seize up a bearing during a race at Reno which may hav= e been due to gyroscopic forces, but I think the flex plate issue just need= s to be fixed by replacing all the flex plates with proper flywheels.=20 > > > =20 > > > Dave Leonard=20 > > >=20 > > > On Fri, Jan 10, 2025, 1:45=E2=80=AFAM Le Roux Breytenbach breytenbach= leroux@gmail.com mailto:breytenbachleroux@gmail.com wrote: > > >=20 > > > > What i can rember was this also a topic on the late Paul L group di= scussion. > > > > Maybe Dave Leonard can chime in - think more that it was gyroscopic= forces 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 ma= ilto:andrew@martinag.com.au wrote: > > > > >=20 > > > > >=20 > > > >=20 > > > > > Maybe some of the cracking flexplates are resulting from starting= issues, the starter motor can hammer the ring gear if not meshing correctl= y or if engine misfires on start. may explain why so many flexplates come p= re-cracked from the wreckers. > > > > > =20 > > > > > Andrew > > > > >=20 > > > > >=20 > > > > >=20 > > > > >=20 > > > > > On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.c= om mailto: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 designe= d to flex (funny that) and cracking is not limited to our setup. > > > > > > There are companies that specialise in stronger flex plates, pa= rticularly for modified and higher horsepower engines. > > > > > >=20 > > > > > > 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? > > > > > >=20 > > > > > > So my take on this is that perhaps the flexing of the plate in = our setup 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 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. > > > > > >=20 > > > > > > Like M, I would appreciate hearing what others know or are thin= king or 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@chart= er.net mailto:cardmarc@charter.net wrote: > > > > > > > > > > > > > > Has the cause of these cracks been uncovered, and if so, what= is the 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@u= wyo.edu mailto:SBoese@uwyo.edu wrote: > > > > > > >> > > > > > > >> Steve, > > > > > > >> > > > > > > >> I didn=E2=80=99t see the cracks prior to disassembly and dou= bt that they could have been seen on the counterweight side very well -if a= t 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 possibl= e with the dampers. Only a few hours of flight have occurred in this confi= guration 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. Pl= ease exercise caution when clicking links or opening attachments from exter= nal sources. > > > > > > >>> > > > > > > >>> > > > > > > >>> Hi Steve > > > > > > >>> > > > > > > >>> Is this recent then? > > > > > > >>> > > > > > > >>> I=E2=80=99m not able to get to my aircraft at present to ch= eck 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 remove 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 T= racy regarding 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/= flyrotary/List.html > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > Homepage: http://www.flyrotary.com/ > > > > > > > Archive and UnSub: http://mail.lancaironline.net:81/lists/f= lyrotary/List.html > > > > > >=20 > > > > > >=20 > > > > > >=20 > > > > > > -- > > > > > > Homepage: http://www.flyrotary.com/ > > > > > > Archive and UnSub: http://mail.lancaironline.net:81/lists/fly= rotary/List.html > > > > > >=20 > > > > >=20 > > > >=20 > > >=20 > >=20 >=20 ------=_Part_1223708_490891432.1736613505276 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =20 =20
I personally re= moved two eng. from the RX7's, heard them start and run, drove one, both ha= d cracks in flex plates. David
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On 01/10/2025 11:50 PM EST Charlie England ceengland7@gmail.com <fly= rotary@lancaironline.net> wrote:
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They do crack in the car, regardless.
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On Fri, Jan 10, 2025 at 10:36=E2=80=AFPM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
=20
=20
Hi there Dave=20
 
=20
I understood the torque converter was driven from the flex plate.&nb= sp;
=20
Can someone confirm how power is transferred from the Eccentric to t= he torque converter?
=20
 
=20
Steve Izett
=20

=20
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On 11 Jan 2025, at 9:35=E2=80=AFam, David Leonard wdleonard@gmail.= com <flyrotary@lancaironline.net> wrote:
=20
=20
=20
in the car, the flex plates are only used to carry the torque fr= om the starter and are not designed to transmit the output of the engine. i= n our setups. We have adapted this flex plate to transmit the entire output= of the engine which it apparently is not up to. =20
 
=20
I had my rd1-b seize up a bearing during a race at Reno which m= ay have been due to gyroscopic forces, but I think the flex plate issue jus= t needs to be fixed by replacing all the flex plates with proper flywheels.=  
=20
 
=20
Dave Leonard 
=20
=20
=20
=20
On Fri, Jan 10, 2025, 1:45=E2=80=AFAM Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:
=20
=20
What i can rember was this also a topic on the late Paul L gro= up discussion.=20
Maybe Dave Leonard can chime in - think more that it was gyro= scopic forces 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
=20
=20
=20
Maybe some of the cracking flexplates are resulting from = starting issues, the starter motor can hammer the ring gear if not meshing = correctly or if engine misfires on start. may explain why so many flexplate= s come pre-cracked from the wreckers.
=20
 
=20
Andrew
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On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.iz= ett@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 a= re designed to flex (funny that) and cracking is not limited to our setup.= =20
There are companies that specialise in stronger flex = plates, particularly for modified and higher horsepower engines.

Since our engines are being used at a higher horsepow= er per unit time and therefore higher stress (assumption) perhaps our setup= could be likened to race applications.
But then our hours of use would be significantly lowe= r (assumption) than an average vehicle, but perhaps not a race application.
Is the cracking we are seeing consistent with race ap= plications? 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 being the latest going down that track and in his case also removi= ng the rubber isolation in the process.
2. Connect direct to the eccentric shaft and therefor= e taking the stress off the Flex Plate doing away with the damping mechanis= m which Tracy did, and perhaps is still doing. Would be real nice to know.

Like M, I would appreciate hearing what others know o= r are thinking or doing.

Steve Izett












> On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese <= a href=3D"mailto:cardmarc@charter.net" target=3D"_blank" rel=3D"noopener">c= ardmarc@charter.net <flyrotary@lancaironline.net> wrot= e:
>=20
> Has the cause of these cracks been uncovered, an= d if so, what 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 dis= assembly and 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 flywhe= el about a year ago.  Since then, I replaced the four rubber dampers w= ith machined aluminum discs giving a solid connection and then dynamically = balanced the system.  This was done because maintaining a dynamic bala= nce wasn=E2=80=99t possible with the dampers.  Only a few hours of fli= ght have occurred in this configuration so far and there has been no indica= tion of problems resulting from this change.
>>=20
>> Steve Boese
>>=20
>>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Ste= phen Izett stephen.izett@gmail.com <flyrotary@lancaironlin= e.net> wrote:
>>>=20
>>> =E2=97=86 This message was sent from a n= on-UWYO address. Please exercise caution when clicking links or opening att= achments from external sources.
>>>=20
>>>=20
>>> Hi Steve
>>>=20
>>> Is this recent then?
>>>=20
>>> I=E2=80=99m not able to get to my aircra= ft at present to check my flex plate which has probably seen 50 hours of se= rvice.
>>>=20
>>> Was it possible to see these cracks asse= mbled?
>>>=20
>>> I would appreciate your reflections on T= racys latter choice to remove the damper, and particularly when using a tim= ber/glass prop such as an MT.
>>>=20
>>> It would be great to have an update and = current info 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.htm= l
>=20
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html



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