X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from pmg.Logan.com ([207.170.160.161] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 3784840 for flyrotary@lancaironline.net; Sat, 11 Jan 2025 14:45:10 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id EEDD73333C for ; Sat, 11 Jan 2025 14:45:09 -0500 (EST) Received-SPF: pass (gmail.com ... _spf.google.com: Sender is authorized to use 'wdleonard@gmail.com' in 'mfrom' identity (mechanism 'include:_netblocks.google.com' matched)) receiver=pmg.Logan.com; identity=mailfrom; envelope-from="wdleonard@gmail.com"; helo=mail-pj1-f43.google.com; client-ip=209.85.216.43 Received: from mail-pj1-f43.google.com (mail-pj1-f43.google.com [209.85.216.43]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Sat, 11 Jan 2025 14:45:09 -0500 (EST) Received: by mail-pj1-f43.google.com with SMTP id 98e67ed59e1d1-2eed82ca5b4so5099704a91.2 for ; Sat, 11 Jan 2025 11:45:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1736624702; x=1737229502; 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=YcRfuRYtN70ftooibSf2n2KhMuZNvr07EpDB6YVANKk=; b=CoMbpayIsmEBI+ULnbrJqwt2thF1UsclxVGhu6HT2OyrPWvcUpW4fb/eEi38iUzi/n vmHxDJADWX5S8DGU99V7/gahxLZbbTabxCu6vIl2C/QNVlHocL0SO1+FJhBM1lb6XX5R aqWUt3ZapKRij9+58r8eNkzOfoi1W8FovGcNrIRy+PM6rzHIqitL6mvkbp388o+qsdcB pW8z4erVAtLsCWbcRzRO7PXgX9gjHfnQ9WUL5ACXmJAx2Yb0r9ATXqsMidewrepyj7PH TVrC1aGrdXY87KcSJe7JVs5miRQ/CUvMRH7K9gpUJc966pfbMT43D7sxeM/lkBli9q3K PbPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736624702; x=1737229502; 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=YcRfuRYtN70ftooibSf2n2KhMuZNvr07EpDB6YVANKk=; b=HN+gfUo7cOLx1mMCxdxsUJ3mwZFFRh32qVYfgW7BCUDhyjzWr/UrDWG1ut2ITkiP0F E0FooC4ZPz8vftbxLc+vPBM+mJDwzMWikX3qCBbrOryn1J4uh4JC87ettl/etHqyuEr5 LBP7UPNdGlcfXriqS1B6t4tmRZ5Aw9QYSR5fISslwwK1rIIXCKPq1pX1bAuQTBLPf+r4 OBW4KFIiK50VxpJoA6MBRIAXy7t+unGhOtUq174VuxRLfgWEi4/WBquoJS/XrKUW9Ccm Pb7DYL/znc96wDdOXU93xTUFEXVqsA7BQ+fo91i1JqYfws1DfKMulu8iuSao/OTiaITw ijfw== X-Gm-Message-State: AOJu0YwWM9rEVz7ey8siA9Cl5XDub4E4JC3JqigHnCX23mOK4mqfon6X Pqi/oqsfBX+1Pizr+L09P00u/ULAPUbBsTv1QmeN6Eka5Ax96hxC2DowuWZNv+4bgdK0ueBsOSm EErfwypIPYuOGg4pVJOqWv/Gt3pf41g== X-Gm-Gg: ASbGncsGH6esB2tOajklpxCZwOg+g0Hu+3pp39y7g2D6L2B8uqhFxjCUDNep0KqyvZ8 9tIm95vOWuzozb1HmKqxtGtncM4O0jj2NPC/0 X-Google-Smtp-Source: AGHT+IEJ/KDt8N6PzPypXZNYCCGHSLZyrsmK44k1h1P3jkAibPKifCzrqd5MqzzAziNcBMJAmP7tRqBBYnKZIV4qN9Q= X-Received: by 2002:a17:90b:4a50:b0:2ea:bf1c:1e3a with SMTP id 98e67ed59e1d1-2f548f2a154mr26566309a91.12.1736624701576; Sat, 11 Jan 2025 11:45:01 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Sat, 11 Jan 2025 11:44:50 -0800 X-Gm-Features: AbW1kvazGK4oqZaj7-U685aO2fFanhohs6yPtV_maif0XPsDJTEzIWEZGmAyGno Message-ID: Subject: Re: [FlyRotary] Re: Flexplate cracks To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="000000000000721d4a062b7372d5" X-SPAM-LEVEL: Spam detection results: 0 AWL -0.515 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_H3 0.001 Good reputation (+3) RCVD_IN_MSPIKE_WL 0.001 Mailspike good senders 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 --000000000000721d4a062b7372d5 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable The counterweight is connected to the eshaft with a key. Then the flex plate bolts directly to the counterweight On Fri, Jan 10, 2025, 8:36 PM Stephen Izett stephen.izett@gmail.com < flyrotary@lancaironline.net> wrote: > 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 need= s > 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 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 >> >> On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au < >> flyrotary@lancaironline.net> wrote: >> >> =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 i= f >> 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 fle= x >>> (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 lik= ened >>> to race applications. >>> But then our hours of use would be significantly lower (assumption) tha= n >>> 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 setu= p >>> 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 stres= s >>> 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. >>> >>> 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- wh= en >>> assembled. >>> >> >>> >> I replaced the Flexplate with a steel flywheel about a year ago. >>> Since then, I replaced the four rubber dampers with machined aluminum d= iscs >>> giving a solid connection and then dynamically balanced the system. Th= is >>> 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 configuratio= n so >>> far and there has been no indication of problems resulting from this ch= ange. >>> >> >>> >> Steve Boese >>> >> >>> >>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett stephen.izett@gm= ail.com < >>> flyrotary@lancaironline.net> wrote: >>> >>> >>> >>> =EF=BB=BF=E2=97=86 This message was sent from a non-UWYO address. P= lease exercise >>> caution when clicking links or opening attachments from external source= s. >>> >>> >>> >>> >>> >>> Hi Steve >>> >>> >>> >>> Is this recent then? >>> >>> >>> >>> I=E2=80=99m not able to get to my aircraft at present to check my f= lex 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 >>> >> > --000000000000721d4a062b7372d5 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
The counterweight is connected to the eshaft with a key. = Then the flex plate bolts directly to the counterweight

On Fri, Jan 10, 2025, 8:36 PM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
Hi th= ere Dave

I understood the torque converter was driven fr= om the flex plate.=C2=A0
Can someone confirm how power is transfe= rred from the Eccentric to the torque converter?

S= teve Izett

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

in the car, the flex plat= es 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 f= lex plate to transmit the entire output of the engine which it apparently i= s not up to.=C2=A0

I had my rd= 1-b seize up a bearing during a race at Reno which may have been due to gyr= oscopic forces, but I think the flex plate issue just needs to be fixed by = replacing all the flex plates with proper flywheels.=C2=A0

Dave Leonard=C2=A0

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 a= lso 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=C2= =A0

On 10 Jan 202= 5, at 08:13, Andrew Martin andrew@martinag.com.au <flyrotary@lancaironline.net> wrote:

=EF=BB=BF
Maybe some of the cracking flexplates are resulting from startin= g issues, the starter motor can hammer the ring gear if not meshing correct= ly 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 step= hen.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 (f= unny that) and cracking is not limited to our setup.
There are companies that specialise in stronger flex plates, particularly f= or modified and higher horsepower engines.

Since our engines are being used at a higher horsepower per unit time and t= herefore higher stress (assumption) perhaps our setup could be likened to r= ace 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 d= ont 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 lat= est going down that track and in his case also removing the rubber isolatio= n in the process.
2. Connect direct to the eccentric shaft and therefore taking the stress of= f 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 doin= g.

Steve Izett












> On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese cardmarc@c= harter.net <flyrotary@lancaironline.net> = wrote:
>
> Has the cause of these cracks been uncovered, and if so, what is the c= urrent 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> w= rote:
>>
>> =EF=BB=BFSteve,
>>
>> 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.= =C2=A0 Since then, I replaced the four rubber dampers with machined aluminu= m discs giving a solid connection and then dynamically balanced the system.= =C2=A0 This was done because maintaining a dynamic balance wasn=E2=80=99t p= ossible 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 res= ulting from this change.
>>
>> Steve Boese
>>
>>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancairo= nline.net> wrote:
>>>
>>> =EF=BB=BF=E2=97=86 This message was sent from a non-UWYO addre= ss. 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 Trac= y regarding his no damper hours if anyone can contact him.
>>>
>>> Very helpful, thanks again Steve
>>>
>>> Steve
>>
>> --
>> Homepage:=C2=A0 http://www.flyrotary.com/
>> Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.h= tml
>
>
>
> --
> Homepage:=C2=A0 http://www.flyrotary.com/ > Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.html<= /a>



--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.html<= br>

--000000000000721d4a062b7372d5--