X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Charlie England ceengland7@gmail.com" Received: from pmg.Logan.com ([207.170.160.161] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 3783125 for flyrotary@lancaironline.net; Fri, 10 Jan 2025 09:36:28 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id 6C34C2AA8A for ; Fri, 10 Jan 2025 09:36:28 -0500 (EST) Received-SPF: pass (gmail.com ... _spf.google.com: Sender is authorized to use 'ceengland7@gmail.com' in 'mfrom' identity (mechanism 'include:_netblocks.google.com' matched)) receiver=pmg.Logan.com; identity=mailfrom; envelope-from="ceengland7@gmail.com"; helo=mail-ej1-f47.google.com; client-ip=209.85.218.47 Received: from mail-ej1-f47.google.com (mail-ej1-f47.google.com [209.85.218.47]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Fri, 10 Jan 2025 09:36:23 -0500 (EST) Received: by mail-ej1-f47.google.com with SMTP id a640c23a62f3a-aaedd529ba1so302861666b.1 for ; Fri, 10 Jan 2025 06:36:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1736519776; x=1737124576; darn=lancaironline.net; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=s0dB0PyTGNCLJVlW56jSGPp2KSHKV9VjfeIztF0nMmA=; b=HkxyAEGah9WgVrPMOKyvag/OAxrTyFr5kX27WCOld6IYhzUZxdk8SbTMdWTCwre7Mn iHKl1f5T5twc0DuxyiHPjhs/erD8Tp9VRwvweS1Tgr+ACSbnvzzuS/WOuyz+PmawUOEY Yw1e+Ztyl0c/D3BqvPdgDV5CEJw32CQHjOinHFYkdhyX2hl158FP/9CHvINiUt1snnTK 4l/KD1+14Il4c6vJyVP5rr8aMKGlFJcyQd2WP+kzdtJ6yQ0RYsqpg2c61g33qt/VxN8q T8i5Tnwwt4EkOd3KgNG2QCbx+WNccyLAxuQ2GjX3zSnyfRm7GL/RoaNxP24wnWX69Z9U X01Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736519776; x=1737124576; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=s0dB0PyTGNCLJVlW56jSGPp2KSHKV9VjfeIztF0nMmA=; b=YvNIl3NWzfSSuctyXJg3ot/VCxh/LxQ4WmpRVFzsPgb8mTEcv48DaWAKX4PBP2BYE3 HY3q93LwcDFogNDhb/Gk44HQR3IAM6HHutZeTe2Uxprvx5+zO2SRsRMg7R7x0UiE4+Lc FbfJXGVOt/GFXi4WJeoaWuub1b67ktVR31q3Uk1EuZHea56663LYbaGxZeJ9q3SjwH6o TV+vnzuCXYKfafyOkbVWPMJKlEUrCTd2hEMY+iyfxI7UHHX8myvvw1pBlYEHceRCETEk S0uGC5RZtOUZTU3KBj575ir/RZORg9Bpv4sa4iHxGae6XbO8J34V23GIdZ7WBH4YiJN+ Dbdw== X-Gm-Message-State: AOJu0YxeDbTxbFq8cNpa9HFvE72Ggx15+MbasiQGZbIgc2w7WfBmVJzz mVN+e8kSYCWWre/ApBRDEN1emKoJgpAb0qWKC3jq/onwz/zdD+89WCntv7uV64MW60ZYww/pz/U ntVi3MikB6XNzNJ4X75wJZHIK68cF9w== X-Gm-Gg: ASbGncvzEtXwLHkkEUqlYuzxqOh7tySXiklDkgojKzwKSE1op8VDhyxNTPgq3PYfGrd n3GNN4MpzzmunFd1iHOLecwCfbN2Hnagbz7P3 X-Google-Smtp-Source: AGHT+IGfa5FqNg4wYTgAdrKqqdKgOBEmfkSFtxULxhKjSJrKjNZWvbXeBWzeGPYLwJ8LppOmCL3532rqmeBMJjMbfVY= X-Received: by 2002:a50:c8ca:0:b0:5d9:84ee:ff31 with SMTP id 4fb4d7f45d1cf-5d984ef7409mr14080241a12.3.1736519774674; Fri, 10 Jan 2025 06:36:14 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Fri, 10 Jan 2025 08:36:03 -0600 X-Gm-Features: AbW1kvbv2i4MqNjM1kF4ygWogGidvNAd-5oWUMakQ-R3GxvZ4TFtTIGTvZIhsZo Message-ID: Subject: Re: [FlyRotary] Re: Flexplate cracks To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000050a4b1062b5b04de" X-SPAM-LEVEL: Spam detection results: 0 AWL -0.947 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_LINEPADDING 1.2 Spam that tries to get past blank line filters KAM_MXURI 1.5 URI begins with a mail exchange prefix, i.e. mx.[...] RCVD_IN_MSPIKE_H2 -0.001 Average reputation (+2) 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 --00000000000050a4b1062b5b04de Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I'm pretty sure David's got it right. I've got a flexplate that's never been run on an aviation engine that's cracked. I really think it's a combination of sloppy design and 'good enough' manufacturing. Look carefully at the lightening holes where the cracks usually start. the holes are punched, with no post-treatment to smooth the sharp edges. Then the sheet is stamped putting stress on the metal around the holes. Perfect recipe for cracks. Len Hanover (you still here, Len?) once speculated that the scrap yards were cracking them by sitting the engines down on the flexplates, but I think they're just cracking from mfg-induced stresses and vibration; even in the car. Charlie On Fri, Jan 10, 2025 at 5:03=E2=80=AFAM David COOK hoursaway1@comcast.net < flyrotary@lancaironline.net> wrote: > Automotive tech for 40 years, 25 years Cadillac. I saw quite a few cracke= d > flexplates. Why, some were self diagnosed, corrosion between starter and > eng. block changed geometry, witness marks that cust. would try to start = a > running 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 starter is shimmed out 1/16", original RWS PSRU-RD1-B, origin= al > starter position. > > > On 01/10/2025 4:44 AM EST Le Roux Breytenbach breytenbachleroux@gmail.com > wrote: > > > What i can rember was this also a topic on the late Paul L group > discussion. > 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 > > Sent from my iPhone > Le Roux Breytenbach > > On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au < > flyrotary@lancaironline.net> wrote: > > 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 flexplates come > pre-cracked from the wreckers. > > Andrew > > > > > On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com < > flyrotary@lancaironline.net> wrote: > > Hi M > > I was wondering the same thing. > > What I discovered first of all was that flex plates are designed to flex > (funny that) and cracking is not limited to our setup. > 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 horsepower per unit time and > therefore higher stress (assumption) perhaps our setup could be likened t= o > race applications. > But then our hours of use would be significantly lower (assumption) 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 being the > latest going down that track and in his case also removing the rubber > isolation in the process. > 2. Connect direct to the eccentric shaft and therefore taking the stress > off the Flex Plate doing away with the damping mechanism which Tracy did, > and perhaps is still doing. Would be real nice to know. > > Like M, I would appreciate hearing what others know or are thinking or > doing. > > Steve Izett > > > > > > > > > > > > > > On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese cardmarc@charter.net < > flyrotary@lancaironline.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@uwyo.edu < > flyrotary@lancaironline.net> wrote: > >> > >> Steve, > >> > >> I didn=E2=80=99t see the cracks prior to disassembly and doubt that th= ey 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. Sinc= e > 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 wi= th 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. > >> > >> Steve Boese > >> > >>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett stephen.izett@gmai= l.com < > flyrotary@lancaironline.net> wrote: > >>> > >>> =E2=97=86 This message was sent from a non-UWYO address. Please exerc= ise > caution when clicking links or opening attachments from external sources. > >>> > >>> > >>> Hi Steve > >>> > >>> Is this recent then? > >>> > >>> I=E2=80=99m not able to get to my aircraft at present to check my fle= x 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 Tracy > 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/flyrotary/List.html > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > --00000000000050a4b1062b5b04de Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I'm pretty sure David's got it right. I've got a = flexplate that's never been run on an aviation engine that's cracke= d. I really think it's a combination of sloppy design=C2=A0and 'goo= d enough' manufacturing. Look carefully at the lightening holes where t= he cracks usually start. the holes are punched, with no post-treatment to s= mooth the sharp edges. Then the sheet is stamped putting stress on the meta= l around the holes. Perfect recipe for cracks.

Len Hanover (you still here, Len?) once speculated th= at the scrap yards were cracking them by sitting the engines down on the fl= explates, but I think they're just cracking from mfg-induced stresses a= nd vibration; even in the car.

Charlie

On Fri, Jan 10, 2025 at 5:03=E2=80= =AFAM David COOK hoursaway1@comca= st.net <flyrotary@lan= caironline.net> wrote:
=20 =20 =20
Automotive tech for= 40 years, 25 years Cadillac. I saw quite a few cracked flexplates. Why, so= me were self diagnosed, corrosion between starter and eng. block changed ge= ometry, witness marks that cust. would try to start a running eng., loose t= orque converter bolts, loose trans to eng. bolts, wrong starter held on wit= h 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 starter is shimmed o= ut 1/16", original RWS PSRU-RD1-B, original starter position.=C2=A0
=20
=C2=A0
=20
=20
On 01/10/2025 4:44 AM EST Le Roux Breytenbach breytenbachleroux@gmail.com <= ;flyrotary= @lancaironline.net> wrote:
=20
=C2=A0
=20
=C2=A0
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=C2=A0
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=20

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

=20
=20
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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
=C2=A0
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Andrew
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On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com <flyrotary@lanca= ironline.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.=C2=A0 Since then, I replaced the four rubber dampers with machin= ed aluminum discs giving a solid connection and then dynamically balanced t= he system.=C2=A0 This was done because maintaining a dynamic balance wasn= =E2=80=99t possible with the dampers.=C2=A0 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:=C2=A0 http://www.flyrotary.com/
>> Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.html
>=20
>=20
>=20
> --
> Homepage:=C2=A0 http://www.flyrotary.com/
> Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.html



--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0h= ttp://mail.lancaironline.net:81/lists/flyrotary/List.html
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