From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] RWS Ring Drive & Damper
Date: Sun, 8 Dec 2024 07:29:51 +0800
References: <list-3731218@lancaironline.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-3731218@lancaironline.net>
Message-Id: <6C25C698-3F1D-471E-BC57-C8B456FC4A03@gmail.com>


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Welcome David.

So if you have the original Input Shaft you would need to build what =
Tracy called the 'Hub Adapter=E2=80=99, obviously with the spine to =
match your =E2=80=98Input Shaft=E2=80=99.

Steve


> On 8 Dec 2024, at 7:18=E2=80=AFam, Stephen Izett =
stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>=20
> Hi Guys
>=20
> This is what I was able get from Tracy re his RD2 version without =
isolator.
>=20
> His early explanation and drawings:
>=20
> Cheers
>=20
> Steve Izett
>=20
> TRACY CROOK email re RD2 modification to remove damper
> =20
> Finally got around to flight testing the aftermarket flywheel setup =
for the RWS redrive.=20
>=20
> The cracked flexplate issue some builders experienced came up at the =
same time as my CNC source for input shafts lost the ability to make =
them anymore due to loss of specialized spline making machinery.  Since =
I had to line up a new source I took this opportunity to review the =
design from the input shaft back to the engine.   Because the damper has =
been such an expensive and labor-intensive part, it was looked at as =
well.   As a result, there have been enough changes to warrant a change =
in the name so the new drives will be RD-2B & RD-2C.
>=20
> In rethinking the drive I had the thought that since the relatively =
low frequency primary resonance range of the drive train is taken care =
of by the system lash, that left only the high frequency harmonics that =
the damper is responsible for.  This high range is the factor that =
creates the red zone in rpm ranges found on some certified engines and =
metal prop combinations.   As far as I know, no one has used a metal =
prop on an RD-1x drive so I decided that it was an unneeded requirement. =
 The new design has no damper at all and consequently it has a "No Metal =
Propeller" restriction.
>=20
> Replacing the damper is a flanged spline that is bolted directly to =
the flywheel using the same bolts (longer bolts required) that attach =
the flywheel to the counterweight.  The spline is a different spec (15 =
splines instead of 30) so it is not compatible with the RD-1 damper but =
the new shaft itself is backward compatible with the remainder of the =
drive.  I retrofitted the same RD-1C that was on my RV-4 for these =
tests.
>=20
> The flywheel was an aluminum racing flywheel with the replaceable iron =
friction surface unbolted and removed.  Really looks pretty and =
professional compared to the flexplate.  Any of the aftermarket RX-7 & =
RX-8 racing flywheels (steel or aluminum) that utilize the auto =
counterweight may be used.=20
>=20
> As David Leonard found, these flywheels place the ring gear about .2" =
closer to the engine than the flexplate.  To compensate, I milled .2" =
off the front surface of the adapter plate where the starter mounts.  No =
changes were needed to the starter itself.   I did not bother to grind =
the lead-in bevel on the ring gear teeth as discussed earlier.   Starter =
engagement was smooth anyway.
>=20
> The RV-4 drive had over 700 hours on it and everything looked =
beautiful inside.  No signs of wear other than a shallow groove (~.002") =
on the input shaft where the 1mm thrust bearing race between the two =
needle bearings rides.  Others have reported more than this in fewer =
hours so this is an area to inspect carefully.  The new input shaft is a =
harder alloy (post machining through hardened 4340) than the the RD-1 =
which was pre hardened 4140.  This should reduce the wear in this area.  =
 The old flexplate with over 1000 hours was still crack free.   The =
input shaft oil seal still looked and felt new so it was not replaced as =
planed.  Others have reported these leaking in much fewer hours.  Don't =
know the reason but I suspect that oil temperatures out of range may be =
a factor.  NEVER allow oil temps to exceed redline.  If they go higher, =
back off the power then land and correct the cooling system.
>=20
> Only 1 hour of flight testing so far but all indications were good.  =
Operated the engine through the full range of rpm up to 7100 looking for =
telltale signs of resonance.   I was sort of expecting to feel, sense or =
hear some indication of increased harshness in the drive with no rubber =
anywhere in the system but if anything, it felt smoother.  There was =
none of the 'Waaa --- Waaa' warbling sound (like a twin engine with the =
engines out of sync) that I had with the Ross drive years ago.  So far =
I'm very satisfied with the results but it's still early in the tests.=20=

>   =20
> Tracy Crook
>=20
> <RD2_HubAdapter.jpeg><RD2inputshaft.jpeg>
>=20
>> On 7 Dec 2024, at 1:41=E2=80=AFam, David Walker drw.aa@hotmail.com =
<flyrotary@lancaironline.net> wrote:
>>=20
>> Hello,
>> New to the group, but longtime advocate and study of the rotary =
engine in Aviation.
>> I am building and RV-4 and thought I had a complete RWS redrive =
assembly.
>> Turns out I am missing the flywheel or ring gear and damper assembly =
that connects the redrive to the motor.
>> Does anyone have a spare? Or know how to fabricate this piece.
>>     David Walker=20
>>            __!__ <image0.jpeg>
>> -----o-(_)-o-----
>=20


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Content-Transfer-Encoding: quoted-printable
Content-Type: text/html;
	charset=utf-8

<html><head><meta http-equiv=3D"content-type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;">Welcome =
David.<div><br></div><div>So if you have the original Input Shaft you =
would need to build what Tracy called the 'Hub Adapter=E2=80=99, =
obviously with the spine to match your =E2=80=98Input =
Shaft=E2=80=99.</div><div><br></div><div>Steve</div><div><br></div><div><b=
r id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote =
type=3D"cite"><div>On 8 Dec 2024, at 7:18=E2=80=AFam, Stephen Izett =
stephen.izett@gmail.com &lt;flyrotary@lancaironline.net&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><div><meta =
http-equiv=3D"content-type" content=3D"text/html; charset=3Dutf-8"><div =
style=3D"overflow-wrap: break-word; -webkit-nbsp-mode: space; =
line-break: after-white-space;">Hi Guys<div><br></div><div>This is what =
I was able get from Tracy re his RD2 version without =
isolator.</div><div><br></div><div>His early explanation and =
drawings:</div><div><br></div><div>Cheers</div><div><br></div><div>Steve =
Izett</div><div><br></div><div><div style=3D"margin: 0mm; font-size: =
medium; font-family: Bree-Light;"><b><span style=3D"font-size: 10pt; =
font-family: Helvetica; color: rgb(68, 68, 68); background: =
white;">TRACY CROOK email re RD2 modification to remove =
damper<o:p></o:p></span></b></div><div style=3D"margin: 0mm; font-size: =
medium; font-family: Bree-Light;"><span style=3D"font-size: 10pt; =
font-family: Helvetica; color: rgb(68, 68, 68); background: =
white;"><o:p>&nbsp;</o:p></span></div><div style=3D"margin: 0mm; =
font-size: medium; font-family: Bree-Light;"><span style=3D"font-size: =
10pt; font-family: Helvetica; color: rgb(68, 68, 68); background: =
white;">Finally got around to flight testing the aftermarket flywheel =
setup for the RWS redrive.&nbsp;</span><span style=3D"font-size: 10pt; =
font-family: Helvetica; color: rgb(68, 68, 68);"><br><br><span =
style=3D"background: white;">The cracked flexplate issue some builders =
experienced came up at the same time as my CNC source for input shafts =
lost the ability to make them anymore due to loss of specialized spline =
making machinery.&nbsp; Since I had to line up a new source I took this =
opportunity to review the design from the input shaft back to the =
engine.&nbsp;&nbsp; Because the damper has been such an expensive and =
labor-intensive part, it was looked at as well.&nbsp;&nbsp; As a result, =
there have been enough changes to warrant a change in the name so the =
new drives will be RD-2B &amp; RD-2C.</span><br><br><span =
style=3D"background: white;">In rethinking the drive I had the thought =
that since the relatively low frequency primary resonance range of the =
drive train is taken care of by the system lash, that left only the high =
frequency harmonics that the damper is responsible for.&nbsp; This high =
range is the factor that creates the red zone in rpm ranges found on =
some certified engines and metal prop combinations. &nbsp; As far as I =
know, no one has used a metal prop on an RD-1x drive so I decided that =
it was an unneeded requirement.&nbsp; The new design has no damper at =
all and consequently it has a "No Metal Propeller" =
restriction.</span><br><br><span style=3D"background: white;">Replacing =
the damper is a flanged spline that is bolted directly to the flywheel =
using the same bolts (longer bolts required) that attach the flywheel to =
the counterweight.&nbsp; The spline is a different spec (15 splines =
instead of 30) so it is not compatible with the RD-1 damper but the new =
shaft itself is backward compatible with the remainder of the =
drive.&nbsp; I retrofitted the same RD-1C that was on my RV-4 for these =
tests.</span><br><br><span style=3D"background: white;">The flywheel was =
an aluminum racing flywheel with the replaceable iron friction surface =
unbolted and removed.&nbsp; Really looks pretty and professional =
compared to the flexplate.&nbsp; Any of the aftermarket RX-7 &amp; RX-8 =
racing flywheels (steel or aluminum) that utilize the auto counterweight =
may be used.&nbsp;</span><br><br><span style=3D"background: white;">As =
David Leonard found, these flywheels place the ring gear about .2" =
closer to the engine than the flexplate.&nbsp; To compensate, I milled =
.2" off the front surface of the adapter plate where the starter =
mounts.&nbsp; No changes were needed to the starter itself.&nbsp;&nbsp; =
I did not bother to grind the lead-in bevel on the ring gear teeth as =
discussed earlier.&nbsp;&nbsp; Starter engagement was smooth =
anyway.</span><br><br><span style=3D"background: white;">The RV-4 drive =
had over 700 hours on it and everything looked beautiful inside.&nbsp; =
No signs of wear other than a shallow groove (~.002") on the input shaft =
where the 1mm thrust bearing race between the two needle bearings =
rides.&nbsp; Others have reported more than this in fewer hours so this =
is an area to inspect carefully.&nbsp; The new input shaft is a harder =
alloy (post machining through hardened 4340) than the the RD-1 which was =
pre hardened 4140.&nbsp; This should reduce the wear in this area. =
&nbsp; The old flexplate with over 1000 hours was still crack =
free.&nbsp;&nbsp; The input shaft oil seal still looked and felt new so =
it was not replaced as planed.&nbsp; Others have reported these leaking =
in much fewer hours.&nbsp; Don't know the reason but I suspect that oil =
temperatures out of range may be a factor.&nbsp; NEVER allow oil temps =
to exceed redline.&nbsp; If they go higher, back off the power then land =
and correct the cooling system.</span><br><br><span style=3D"background: =
white;">Only 1 hour of flight testing so far but all indications were =
good.&nbsp; Operated the engine through the full range of rpm up to 7100 =
looking for telltale signs of resonance.&nbsp;&nbsp; I was sort of =
expecting to feel, sense or hear some indication of increased harshness =
in the drive with no rubber anywhere in the system but if anything, it =
felt smoother.&nbsp; There was none of the 'Waaa --- Waaa' warbling =
sound (like a twin engine with the engines out of sync) that I had with =
the Ross drive years ago.&nbsp; So far I'm very satisfied with the =
results but it's still early in the tests.&nbsp;</span><br><span =
style=3D"background: white;">&nbsp;&nbsp;&nbsp;</span><br><span =
style=3D"background: white;">Tracy Crook</span></span><span =
style=3D"font-size: 10pt; font-family: &quot;Times New Roman&quot;, =
serif;"><o:p></o:p></span></div></div><div><br></div><div><span =
id=3D"cid:9E6502EE-E42F-406C-8DC5-E5DA2800E1F9">&lt;RD2_HubAdapter.jpeg&gt=
;</span><span =
id=3D"cid:7F908230-060F-4C70-8EBB-7CB79314EB7E">&lt;RD2inputshaft.jpeg&gt;=
</span></div><div><div><br><blockquote type=3D"cite"><div>On 7 Dec 2024, =
at 1:41=E2=80=AFam, David Walker drw.aa@hotmail.com =
&lt;flyrotary@lancaironline.net&gt; wrote:</div><br =
class=3D"Apple-interchange-newline"><div>

<meta http-equiv=3D"Content-Type" content=3D"text/html; =
charset=3Dus-ascii">

<div dir=3D"auto">
<span style=3D"-webkit-text-size-adjust: auto; background-color: =
rgb(255, 255, 255);">Hello,</span>
<div style=3D"-webkit-text-size-adjust: auto;">New to the group, but =
longtime advocate and study of the rotary engine in Aviation.</div>
<div style=3D"-webkit-text-size-adjust: auto;">I am building and RV-4 =
and thought I had a complete RWS redrive assembly.</div>
<div style=3D"-webkit-text-size-adjust: auto;">Turns out I am missing =
the flywheel or ring gear and damper assembly that connects the redrive =
to the motor.</div>
<div style=3D"-webkit-text-size-adjust: auto;">Does anyone have a spare? =
Or know how to fabricate this piece.</div>
<div dir=3D"ltr"><div style=3D"margin: 0in 0in 0.0001pt;"><span =
style=3D"background-color: rgba(255, 255, 255, 0);">&nbsp; &nbsp; David =
Walker&nbsp;</span></div>
<div><div style=3D"margin: 0in 0in 0.0001pt;"><span =
style=3D"background-color: rgba(255, 255, 255, 0);">&nbsp; &nbsp; &nbsp; =
&nbsp; &nbsp; &nbsp;__!__&nbsp;<span =
id=3D"cid:mf_638822B1-5D46-4881-885E-A82BAF8ED310/L0/001">&lt;image0.jpeg&=
gt;</span><o:p></o:p></span></div>
</div>
<div id=3D"divRplyFwdMsg"><div style=3D"margin: 0in 0in 0.0001pt;"><span =
style=3D"background-color: rgba(255, 255, 255, =
0);">-----o-(_)-o-----</span></div>
</div>
</div>
</div>

=
</div></blockquote></div><br></div></div></div></blockquote></div><br></di=
v></body></html>=

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