X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Stephen Izett stephen.izett@gmail.com" Received: from pmg.Logan.com ([207.170.160.161] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 3784100 for flyrotary@lancaironline.net; Fri, 10 Jan 2025 23:34:09 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id E241630208 for ; Fri, 10 Jan 2025 23:34:08 -0500 (EST) Received-SPF: pass (gmail.com ... _spf.google.com: Sender is authorized to use 'stephen.izett@gmail.com' in 'mfrom' identity (mechanism 'include:_netblocks.google.com' matched)) receiver=pmg.Logan.com; identity=mailfrom; envelope-from="stephen.izett@gmail.com"; helo=mail-pl1-f171.google.com; client-ip=209.85.214.171 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Fri, 10 Jan 2025 23:34:07 -0500 (EST) Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2166f1e589cso55602625ad.3 for ; Fri, 10 Jan 2025 20:34:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1736570041; x=1737174841; darn=lancaironline.net; h=message-id:in-reply-to:to:references:date:subject:mime-version:from :from:to:cc:subject:date:message-id:reply-to; bh=SK5d1SiJpnD31urTXJyXh/lNfc6ZTS4tgPG27Yv4h8Q=; b=k9avem57yE2kS+ZyUIFasPkW/m9Y6pTVB5552+3T681y/ME+XfwtgzzNfYehjWL53V eWNL7DivfY6cQMEkbxBQcOj66qQHW1zsBu+xBCXwMTxGSIjRYBfacV3+3ZlOLctrjY4Z 1+jtbv3hNIso0ARU4aj9/88njB/U6YvbSTPokj/FAqcIxCrb6hIlJPm8BcMrTBznJ893 NbExYOoIXsSfbtW6DU9pw5w27278IUwrHimi5LvSx9IftjMRNcK7nuODpZGqFttr5btb vJJEgKLlpcK6U3voiAoGVQgn7kzqsREOrr9928G0HLWO56Cr5+yc28qJgy4Sge2j5q1N hxLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736570041; x=1737174841; h=message-id:in-reply-to:to:references:date:subject:mime-version:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=SK5d1SiJpnD31urTXJyXh/lNfc6ZTS4tgPG27Yv4h8Q=; b=Zor8pZ2Pl0Gk0fCio5wqFTRSStPJjzF7Lp9uxi9rabvGWVcZl2aCf5Zp+dxro8ARVi k5jm+HsoZPMuapPUGhpAgCLErMfVSnk3GzCJeaM9ZIqvbwOR546faY1UisXcD/k3394F 9JbIKRKHwqtGI00vvjhrvLJ/KMInKGSMTMmHhNmd8S02mjvY0UAlRWRiMN43x6hQMXNj E1L0S2RWnjncJ6n+GcbG6q2e6U0Gra/iqz1kj8iOKYkxv1THLF+84KTBs/DiIBtSFqXf X7wNdsjditf6gOvJou4zuBiSn2P3BD/DxufQSS1XhrW3IAVdCKxOINk+00N3UWp7Frwv ZEKQ== X-Gm-Message-State: AOJu0YxohJ/xWmkOJLsw/LCMQ9i6vueoto6tNFPkjUoYHYyONBn7rAIU Iupfunq+OMPb/5y2hBN9fxYrkx2vTqV74Gpt4QoQ2jhqJy2p16w3+kNwrA== X-Gm-Gg: ASbGncsBmHVbiW382RAO5DNj93tt8j/yBgb72ZmM40Ioe8jobM0kqU+lYa0Y2QD1vnQ dIdABHPSfvpuHKuafHCqQuTG7CPJupShg2Mt9NmOsb/DyialpnmCJRm0ceqapKikhqzYL1EKE2V htfwpOKa6Ku2xwHW9kOIoO5esG7Uf7iIsUk1rrq56tD2EBJ2yaWz9aAhu8mg+9n/nb5GvHjao+E vYqoAWGqPFJ29r5QPv5j8zely+1/+VpDqF5VcEy4DPjXFmVZ9v6feF2nvbHYH2iyiWJQICZBd+Z 5g== X-Google-Smtp-Source: AGHT+IFbA4nxPvlFEX915+OQN++G4pLknWcspKNFPn3aiZK1FH7sCD7E/YwEg9xan3bgsHOBce17yA== X-Received: by 2002:a17:903:2451:b0:215:b74c:d7ad with SMTP id d9443c01a7336-21a83fc389cmr213650685ad.36.1736570040314; Fri, 10 Jan 2025 20:34:00 -0800 (PST) Received: from smtpclient.apple ([1.127.104.167]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-21a9f219e44sm20253735ad.120.2025.01.10.20.33.58 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Jan 2025 20:34:00 -0800 (PST) Content-Type: multipart/alternative; boundary="Apple-Mail=_30E223B2-495E-476E-8B00-69A58F984DCA" Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.200.121\)) Subject: Re: [FlyRotary] Flexplate cracks Date: Sat, 11 Jan 2025 12:33:45 +0800 References: To: Rotary motors in aircraft In-Reply-To: Message-Id: X-Mailer: Apple Mail (2.3826.200.121) X-SPAM-LEVEL: Spam detection results: 0 AWL -1.249 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% CBJ_GiveMeABreak 1.75 Messages with consecutive break characters 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_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_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 --Apple-Mail=_30E223B2-495E-476E-8B00-69A58F984DCA Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi there Dave 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? Steve Izett > On 11 Jan 2025, at 9:35=E2=80=AFam, David Leonard wdleonard@gmail.com = wrote: >=20 > in the car, the flex plates are only used to carry the torque from the = 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 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 may have = been due to gyroscopic forces, but I think the flex plate issue just = needs 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 = 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 = 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 >>> On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au = > wrote: >>>=20 >>> =EF=BB=BF >>> 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. >>>=20 >>> Andrew >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>> On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com = > wrote: >>>> Hi M >>>>=20 >>>> I was wondering the same thing.=20 >>>>=20 >>>> What I discovered first of all was that flex plates are 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. >>>>=20 >>>> Since our engines are being used at a higher horsepower 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 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? >>>>=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 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. >>>>=20 >>>> Like M, I would appreciate hearing what others know or are thinking = 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@charter.net = > = wrote: >>>> >=20 >>>> > 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 >>>> >=20 >>>> >> On Jan 9, 2025, at 1:31=E2=80=AFAM, Steven W. Boese = SBoese@uwyo.edu > wrote: >>>> >>=20 >>>> >> =EF=BB=BFSteve, >>>> >>=20 >>>> >> I didn=E2=80=99t see the cracks prior to disassembly 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 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=99= t 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 = > = wrote: >>>> >>>=20 >>>> >>> =EF=BB=BF=E2=97=86 This message was sent from a non-UWYO = address. Please exercise caution when clicking links or opening = attachments from external sources. >>>> >>>=20 >>>> >>>=20 >>>> >>> Hi Steve >>>> >>>=20 >>>> >>> Is this recent then? >>>> >>>=20 >>>> >>> 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. >>>> >>>=20 >>>> >>> Was it possible to see these cracks assembled? >>>> >>>=20 >>>> >>> 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. >>>> >>>=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.html >>>> >=20 >>>> >=20 >>>> >=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 --Apple-Mail=_30E223B2-495E-476E-8B00-69A58F984DCA Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Hi there = Dave

I understood the torque converter was driven = from the flex plate. 
Can someone confirm how power is = transferred from the Eccentric to the torque = converter?

Steve Izett

On 11 Jan 2025, at 9:35=E2=80=AFam, David Leonard = wdleonard@gmail.com <flyrotary@lancaironline.net> wrote:

in the car, = the flex plates are only used to carry the torque from the 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 the engine = which it apparently is not up to. 

I had my rd1-b seize up a bearing during a race at Reno = which may have been due to gyroscopic forces, but I think the flex plate = issue just needs to be fixed by replacing all the flex plates with = proper flywheels. 

Dave Leonard 

On Fri, Jan = 10, 2025, 1:45=E2=80=AFAM Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> 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 forces that craked the plates
Maybe i can = find the photos and topic in my old mails

Sent from my iPhone
Le Roux = Breytenbach 
=EF=BB=BF
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





<= div class=3D"gmail_quote">
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 to 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:
>>
>> =EF=BB=BFSteve,
>>
>> I didn=E2=80=99t see the cracks prior to disassembly and doubt = that 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 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@gmail.com <flyrotary@lancaironline.net> wrote:
>>>
>>> =EF=BB=BF=E2=97=86 This message was sent from a non-UWYO = address. Please exercise 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 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 = 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.ht= ml
>
>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.ht= ml



--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.ht= ml

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