X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) From: "Charlie England ceengland7@gmail.com" Received: from mail-io1-f53.google.com ([209.85.166.53] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 1017884 for flyrotary@lancaironline.net; Mon, 07 Dec 2020 16:08:33 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.166.53; envelope-from=ceengland7@gmail.com Received: by mail-io1-f53.google.com with SMTP id p187so14808904iod.4 for ; Mon, 07 Dec 2020 13:08:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=YtmvF23eo3rnbZSXPBVlLZM4b/4TOgmR2AFSZLWBpTk=; b=mn9wm6e319ZOM+W6Dhab+iTeQFMjT1aa+Hc4NtYQzaRQogl4TNf32XftZl56+3aexm dwZmJZ43CVDr9SUvOLrP6886wtajcxGIF/OOliMcMZ5uupNCX5C8sdZYHn8yqN3rHLjB N3NNWdVu6nqflk5ZHb63QZW4vW2WEx9EpErFI7sSkSWVVsykjQiyiWbaZQ1Yy2RzwbOm ruFSbh6bhnzjd9I+bx3FChJBzVtLvGP4vL/Sy+5dYrhVvCPapdwATOdlXdMd6I+1dgGZ 7xwTr0akkOUSDwiT3fkI4H/qroxm2R9RRlN/7ro+GOyJiRJoz4+8TC2VHEgOid1XiNqe mm4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=YtmvF23eo3rnbZSXPBVlLZM4b/4TOgmR2AFSZLWBpTk=; b=dtIXLb5wRgLvNW/e2Wl7dtK85NH53o7jBsd9Cr5dfpiU9V+9TQZ83y7QNfHhSV5bNB dR5eOusq5zOnENuDDZLgbDolMnLVj4lYldC3CqTZ+yaD7Sfic9bHWQM6mDEfk/VakdgY z1zX/FwC2zhppHA0jGqCvZJ+yqh3j9sAR7gtplOb1p6dah+AUD1RMwNvANCgIx+bOEhC Gp3G28A7o4xSgejSogluAb1pdM9hCEooz7XmoNyOHUk33iKrBeQ0mDctOM4zVqAtKbE4 RKf2WQIqha7dKdMTx1EVlX9fH+buj3weGtTc2moDFmGQW9cX2zd6wjR4+fzAZVWRciMv 1XfA== X-Gm-Message-State: AOAM531NDQ5t/CmUzKxreligWCwNfdhp3tWvexzU+NKUjdcWeupF/fgP fhtR0lDiDsaMDSNhzeNQLQ3SV9LkhrzfInYmrvVt9PyjaiY= X-Google-Smtp-Source: ABdhPJxmq1ulPa9+wF8wKUunD7JGj7jVD9hLGq8VDcHnMIW2e/PDEjXvKyisbDnBA+Dlwqz+7REfQi9626tIznuUHSA= X-Received: by 2002:a02:830f:: with SMTP id v15mr24022978jag.12.1607375295933; Mon, 07 Dec 2020 13:08:15 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Mon, 7 Dec 2020 15:03:10 -0600 Message-ID: Subject: Re: [FlyRotary] Re: RD1-C damper To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000088f2b505b5e639e0" --00000000000088f2b505b5e639e0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, Dec 7, 2020 at 8:20 AM Ernest Christley echristley@att.net < flyrotary@lancaironline.net> wrote: > The temperature in that area will range from around 180F to well below > freezing on a cold night, resulting in a lot of differential expansion. > Epoxy is basically plastic. It is going to soften in use, when its > strength is needed most. > > This is something I'd probably try, but I wouldn't bet money that it woul= d > work. > > On Monday, December 7, 2020, 5:29:25 AM EST, Le Roux Breytenbach > breytenbachleroux@gmail.com wrote: > > > > Hi : It was mentioned on P.L. newsletter a couple of years ago - what if > the flexplate center are reinforced with say 6 layers of carbonfiber on > both sides ? > The carbonfiber can be vacumebag and really good cured if doiing it from > both sides. > The carbonfiber will lock from both sides face to face threw the bigger > holes and will secure more than just on the metal itself. > Doiing the flexplate as a complete unit and then just cut and machine the > holes. > It will be ridged and light as well and counter the gyroscopic forces > ect.that leads to cracks from the holes > Then the rubber dampener could still be put in place. > I am goiing to replace the center on this clutchplate with a rubber > dampener > > > > Regards Le Roux > > > Sent from my iPhone > Le Roux Breytenbach > > > On 07 Dec 2020, at 09:07, Stephen Izett stephen.izett@gmail.com < > flyrotary@lancaironline.net> wrote: > > > > =EF=BB=BFSee below what Tracy wrote in Feb 2012. > > Also found a note in the archive where Tracy mentions only producing a > few of the RD-2 boxes before retiring. > > So how many hours does Tracy=E2=80=99s RV4 with the damper removed now = have on > it. > > Sounds from what some have said that he may have installed this mod to > his 20B RV8 which may have more time, however thats a 3 rotor. What > difference would that make I wonder? > > I take it the torque reversal and pulses will be the same magnitude but > the sum of those pulses may have a different outcome for anything connect= ed. > > > > Cheers > > > > Steve Izett > > > > > > email from Tracy back in Feb 2012 - > > "Finally got around to flight testing the aftermarket flywheel setup fo= r > the RWS redrive. > > > > 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 th= e > 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 resul= t, > there have been enough changes to warrant a change in the name so the new > drives will be RD-2B & RD-2C. > > > > 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 th= e > 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 h= as > no damper at all and consequently it has a "No Metal Propeller" restricti= on. > > > > 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 spline= s > 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. > > > > 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. > > > > 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. > > > > 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 inp= ut > 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 report= ed > 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 temp= s > to exceed redline. If they go higher, back off the power then land and > correct the cooling system. > > > > 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 > tell-tale 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 engine= s > 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.=E2=80=9D > > > > > > > > > > > >> On 7 Dec 2020, at 9:47 am, Stephen Izett stephen.izett@gmail.com < > flyrotary@lancaironline.net> wrote: > >> > >> Thanks Lynn. > >> > >> Steve > >> > >> > >>>> On 7 Dec 2020, at 9:04 am, lehanover lehanover@aol.com < > flyrotary@lancaironline.net> wrote: > >>> > >>> If you have picked up a stock manual transmission flywheel for a > rotary, you must know that "Houston we have a problem". So the worst pick > for a car engine becomes the best pick for smoothness at idle. That > flywheel is the answer. The less flywheel effect available the more > powerful the reversals near idle. The more powerful the reversals the > shorter the flex plate life. The flex plate drives the car through a > hydraulic damper. So it is with the aircraft. No damper, short life. Ther= e > are companies who make little tiny shock absorbers. I thought that 4 such > shocks on a racing flywheel pushing a driven disc should do the job. Even > stock flex plates from piston powered cars get cracks. Few fail completel= y. > >>> > >>> I think Tracy's pucks are adequate. Just double up the flex plate to > just outboard of the puck housings. No welding. Use nuts and bolts. It > also adds actual flywheel effect which reduces the stress. > >>> For the racer I made a steel button flywheel. Just large enough to > support a 2 disc 5 1/4" clutch. I bolted this on over the stock flex plat= e. > The flex plate was just used to start the engine and nothing else. I turn= ed > down the face of the counter weight so as to provide a taller spigot to > locate the flex plate and the flywheel. Piece of cake. > >>> > >>> The racer used a straight cut gear dog ring style gear box from Saenz > in Argentina. The gears had enough clearance so as to agree with various > RPMs. As on start up form a stand still the RPMs would drop below 2,200 a= nd > the car sounded like a Brush Hog running over a pile of hammer heads. Tha= t > is what you want to avoid. > >>> > >>> Also when unloaded even at higher RPM. The same thing. So when > feathering the throttle like in third gear. When the engine is not drivin= g > the wheels and the wheels are not driving the engine. Maybe as on final y= ou > might get into this situation. So a bit more power, or, a bit less power > will save the day. > >>> > >>> The teem had a very competent engineer. My hands are still > dirty............... Lynn E. Hanover > >>> > >>> In a message dated 12/6/2020 5:28:22 PM Eastern Standard Time, > flyrotary@lancaironline.net writes: > >>> > >>> Thanks Dave. > >>> > >>> Did you do away with your damper after your flax plate > disintegrated/failed over time, or was this still before Tracy changed hi= s > mind about the need for the "higher frequency=E2=80=9D isolation provided= by the > damper? > >>> > >>> I was trying to think about the forces at work on that thin steel > plate apart from the torque of your boosted 300 hp. > >>> I was wondering about the gyroscopic (is that the right word) force > created by that extra mass bolted to it, travelling at much higher > velocity, and then being asked to change direction with the subsequent > =E2=80=9Cflexing=E2=80=9D forces at play. > >>> Steve Boese=E2=80=99 science/engineering mind or Lynn Hanover=E2=80= =99s hands dirty > experience appreciated at this point! > >>> > >>> Thanks also to Dave Leonard for what we have learnt from your need fo= r > speed, and Neil Unger=E2=80=99s relentless work on gearboxes. > >>> > >>> So there being evidence of failure outside of aircraft use, I'll look > into another stronger starter ring gear. > >>> > >>> BUT more to the point. what experience do we now have of removing the > damper altogether? > >>> I thought this was the important question, because if not required, > appears to save significant: weight, cost, and maintenance. > >>> > >>> Has there been further word from Tracy or anyone else flying the RD2 > or other no-isolator setups? > >>> Tracy=E2=80=99s initial testing appeared promising but thats now some= years > back. > >>> > >>> Thanks heaps everyone. Couldn't have got this far without your brains= , > pain, cheque book, experience etc. > >>> > >>> Cheers > >>> > >>> Steve Izett > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>>> On 7 Dec 2020, at 12:52 am, David Leonard wdleonard@gmail.com < > flyrotary@lancaironline.net> wrote: > >>>> > >>>> Steve, you are right. The Issue is cracking og the auto-tranny flex > plate. Mine failed entirely. I highly recommend making the change soone= r > rather than later. > >>>> > >>>> Dave Leonard > >>>> > >>>> On Sun, Dec 6, 2020, 12:48 AM Stephen Izett stephen.izett@gmail.com = < > flyrotary@lancaironline.net> wrote: > >>>> Hi Charlie > >>>> > >>>> I thought people moved to the race flywheels because the flex plates > were cracking. > >>>> I hadn=E2=80=99t heard of the Engine/Drive/Prop needing a flywheel m= ass. > >>>> I found some info on the forum archive but nothing to draw it all > together. > >>>> I=E2=80=99ll have a good look at the flexplate when I pull the drive= and > check for cracking, but unless I hear otherwise I plan to reuse the flex > plate. > >>>> > >>>> Thanks > >>>> > >>>> Steve > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>>> On 6 Dec 2020, at 8:58 am, Charlie England ceengland7@gmail.com < > flyrotary@lancaironline.net> wrote: > >>>>> > >>>>> On 12/5/2020 6:35 PM, Stephen Izett stephen.izett@gmail.com wrote: > >>>>>> Hi team > >>>>>> > >>>>>> Having completed phase #1 testing of the Glasair Super IIRG power > by Renesis and RD1-C redrive, I=E2=80=99re going to pull the redrive for = its 25 > hourly initial inspection. > >>>>>> > >>>>>> Tracy deleted the damper assembly from the last rendition of his > design and I=E2=80=99m considering removing ours by creating a new adapte= r plate > from the existing splined > >>>>>> part that is currently riveted to the damper and adding some longe= r > bolts and spacers. > >>>>>> > >>>>>> Has anyone heard anything further in regard to RD receives with th= e > damper removed? > >>>>>> Has Tracy given any further updatess? > >>>>>> All I have read was after initial tests some years ago. > >>>>>> > >>>>>> Cheers > >>>>>> > >>>>>> Steve. > >>>>> Best I remember is that you need either an aluminum or steel racing > flywheel, to get more mass on the engine side of the system. IIRC, it's > also limited to low mass (wood, etc) propellers. The ones he sold had a > different input shaft, but I think Dave Leonard modified his RD1-C & to u= se > a steel racing flywheel which was only slightly heavier than the aluminum > version. Search for Dave's posts, if he doesn't chime in. I've been > wondering if Guibo/Rototflex couplers could be a viable alternative to th= e > aluminum plate/rubber discs. Probably would weigh more, and definitely co= st > more. > >>>>> > >>>>> Charlie > FWIW, in the car, the torque converter seems to be bolted to the flexplate using the same holes that Tracy's adapter uses. Looking at the RX8 service manual, there may be a narrow sheet metal adapter ring between the flex plate bolt circle and the torque converter, but not much else in the way of structural reinforcement. (Of course, the torque converter housing itself may act as stiffener.) It *seems* logical to me that if there were going to be stress cracks caused by flying the assembly, they'd show up in the aluminum adapter plate before the steel flex plate. And cracking usually starts where there's a 'stress riser'; a notch or deep scratch in an edge. The only plates I've observed have un-dressed, sharp edged punched holes where the cracks seem to originate. I don't know whether it will help, but I attacked my uncracked flex plate with a die grinder & files to clean up all the accessible edges of holes, etc, as we do with any aluminum parts, before assembling everything. Again, just my opinion, but I think that the real benefit of the extra mass of a flywheel is pulse isolation from the gearbox. Charlie --00000000000088f2b505b5e639e0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Mon, Dec 7, 2020 at 8:20 AM Ernest Christley echristley@att.net <flyrotary@lancaironline.net> wrote= :
The temperature in that area will range from aroun= d 180F to well below freezing on a cold night, resulting in a lot of differ= ential expansion.=C2=A0 Epoxy is basically plastic.=C2=A0 It is going to so= ften in use, when its strength is needed most.

This is something I'd probably try, but I wouldn&#= 39;t bet money that it would work.

=20
=20
On Monday, December 7, 2020, 5:29:25 AM EST, Le Roux Br= eytenbach = breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:



Hi : It wa= s mentioned on P.L. newsletter a couple of years ago - what if the flexplat= e center are reinforced with say 6 layers of carbonfiber on both sides ?
The carbonfiber can be vacumebag and really good cu= red if doiing it from both sides.
The carbonfiber= will lock from both sides face to face threw the bigger holes and will sec= ure more than just on the metal itself.
Doiing th= e flexplate as a complete unit and then just cut and machine the holes.
=
It will be ridged and light as well and counter the = gyroscopic forces ect.that leads to cracks from the holes
Then the rubber dampener could still be put in place.
I am goiing to replace the center on this clutchplate with a= rubber dampener



Regards Le Roux


Sent from my i= Phone
Le Roux Breytenbach

> On 07 Dec 2020, at 09:07, Stephen= Izett stephen= .izett@gmail.com <flyrotary@lancaironline.net> wrote:
>
> = =EF=BB=BFSee below what Tracy wrote in Feb 2012.
> Also found a note = in the archive where Tracy mentions only producing a few of the RD-2 boxes = before retiring.
> So how many hours does Tracy=E2=80=99s RV4 with th= e damper removed now have on it.
> Sounds from what some have said t= hat he may have installed this mod to his 20B RV8 which may have more time,= however thats a 3 rotor. What difference would that make I wonder?
>= ; I take it the torque reversal and pulses will be the same magnitude but t= he sum of those pulses may have a different outcome for anything connected.=
>
> Cheers
>
> Steve Izett
>
>
= > email from Tracy back in Feb 2012 -
> "Finally got around t= o flight testing the aftermarket flywheel setup for the RWS redrive.
&g= t;
> The cracked flexplate issue some builders experienced came up a= t 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.=C2=A0 Sinc= e I had to line up a new source I took this opportunity to review the desig= n from the input shaft back to the engine.=C2=A0 Because the damper has be= en such an expensive and labor intensive part, it was looked at as well.=C2= =A0 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.
>
> In reth= inking 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 l= ash, that left only the high frequency harmonics that the damper is respons= ible for.=C2=A0 This high range is the factor that creates the red zone in = rpm ranges found on some certified engines and metal prop combinations.=C2= =A0 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.=C2=A0 The new design has no da= mper at all and consequently it has a "No Metal Propeller" restri= ction.
>
> Replacing the damper is a flanged spline that is bo= lted directly to the flywheel using the same bolts (longer bolts required) = that attach the flywheel to the counterweight.=C2=A0 The spline is a differ= ent spec (15 splines instead of 30) so it is not compatible with the RD-1 d= amper but the new shaft itself is backward compatible with the remainder of= the drive.=C2=A0 I retrofitted the same RD-1C that was on my RV-4 for thes= e tests.
>
> The flywheel was an aluminum racing flywheel with= the replaceable iron friction surface unbolted and removed.=C2=A0 Really l= ooks pretty and professional compared to the flexplate.=C2=A0 Any of the af= termarket RX-7 & RX-8 racing flywheels (steel or aluminum) that utilize= the auto counterweight may be used.
>
> As David Leonard fou= nd, these flywheels place the ring gear about .2" closer to the engine= than the flexplate.=C2=A0 To compensate, I milled .2" off the front s= urface of the adapter plate where the starter mounts.=C2=A0 No changes were= needed to the starter itself.=C2=A0 I did not bother to grind the lead-in= bevel on the ring gear teeth as discussed earlier.=C2=A0 Starter engageme= nt was smooth anyway.
>
> The RV-4 drive had over 700 hours on= it and everything looked beautiful inside.=C2=A0 No signs of wear other th= an a shallow groove (~.002") on the input shaft where the 1mm thrust b= earing race between the two needle bearings rides.=C2=A0 Others have report= ed more than this in fewer hours so this is an area to inspect carefully.= =C2=A0 The new input shaft is a harder alloy (post machining through harden= ed 4340) than the the RD-1 which was pre hardened 4140.=C2=A0 This should r= educe the wear in this area.=C2=A0 The old flexplate with over 1000 hours = was still crack free.=C2=A0 The input shaft oil seal still looked and felt= new so it was not replaced as planed.=C2=A0 Others have reported these lea= king in much fewer hours.=C2=A0 Don't know the reason but I suspect tha= t oil temperatures out of range may be a factor.=C2=A0 NEVER allow oil temp= s to exceed redline.=C2=A0 If they go higher, back off the power then land = and correct the cooling system.
>
> Only 1 hour of flight test= ing so far but all indications were good.=C2=A0 Operated the engine through= the full range of rpm up to 7100 looking for tell-tale signs of resonance.= =C2=A0 I was sort of expecting to feel, sense or hear some indication of i= ncreased harshness in the drive with no rubber anywhere in the system but i= f anything, it felt smoother.=C2=A0 There was none of the 'Waaa --- Waa= a' warbling sound (like a twin engine with the engines out of sync) tha= t I had with the Ross drive years ago.=C2=A0 So far I'm very satisfied = with the results but it's still early in the tests.=E2=80=9D
> >
>
>
>
>> On 7 Dec 2020, at 9:47 am, S= tephen Izett s= tephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>>=
>> Thanks Lynn.
>>
>> Steve
>>
&= gt;>
>>>> On 7 Dec 2020, at 9:04 am, lehanover lehanover@aol.com <<= a href=3D"mailto:flyrotary@lancaironline.net" target=3D"_blank">flyrotary@l= ancaironline.net> wrote:
>>>
>>> If you hav= e picked up a stock manual transmission flywheel for a rotary, you must kno= w that "Houston we have a problem". So the worst pick for a car e= ngine becomes the best pick for smoothness at idle. That flywheel is the an= swer. The less flywheel effect available the more powerful the reversals ne= ar idle. The more powerful the reversals the shorter the flex plate life. T= he flex plate drives the car through a hydraulic damper. So it is with the = aircraft. No damper, short life. There are companies who make little tiny s= hock absorbers. I thought that 4 such shocks on a racing flywheel pushing a= driven disc should do the job. Even stock flex plates from piston powered = cars get cracks. Few fail completely.
>>>
>>> I th= ink Tracy's pucks are adequate. Just double up the flex plate to just o= utboard of the puck housings. No welding. Use nuts and bolts.=C2=A0 It also= adds actual flywheel effect which reduces the stress.=C2=A0
>>&g= t; For the racer I made a steel button flywheel. Just large enough to suppo= rt a 2 disc 5 1/4" clutch. I bolted this on over the stock flex plate.= The flex plate was just used to start the engine and nothing else. I turne= d down the face of the counter weight so as to provide a taller spigot to l= ocate the flex plate and the flywheel. Piece of cake.
>>>
= >>> The racer used a straight cut gear dog ring style gear box fro= m Saenz in Argentina. The gears had enough clearance so as to agree with va= rious RPMs. As on start up form a stand still the RPMs would drop below 2,2= 00 and the car sounded like a Brush Hog running over a pile of hammer heads= . That is what you want to avoid.
>>>
>>> Also wh= en unloaded even at higher RPM. The same thing. So when feathering the thro= ttle like in third gear. When the engine is not driving the wheels and the = wheels are not driving the engine. Maybe as on final you might get into thi= s situation. So a bit more power, or, a bit less power will save the day.>>>
>>> The teem had a very competent engineer. My = hands are still dirty............... Lynn E. Hanover=C2=A0
>>>=
>>> In a message dated 12/6/2020 5:28:22 PM Eastern Standard = Time, flyr= otary@lancaironline.net writes:
>>>
>>> Thanks= Dave.
>>>
>>> Did you do away with your damper af= ter your flax plate disintegrated/failed over time, or was this still befor= e Tracy changed his mind about the need for the "higher frequency=E2= =80=9D isolation provided by the damper?
>>>
>>> I= was trying to think about the forces at work on that thin steel plate apar= t from the torque of your boosted 300 hp.
>>> I was wondering a= bout the gyroscopic (is that the right word) force created by that extra ma= ss bolted to it, travelling at much higher velocity, and then being asked t= o change direction with the subsequent =E2=80=9Cflexing=E2=80=9D forces at = play.
>>> Steve Boese=E2=80=99 science/engineering mind or Lynn= Hanover=E2=80=99s hands dirty experience appreciated at this point!
>= ;>>
>>> Thanks also to Dave Leonard for what we have lea= rnt from your need for speed, and Neil Unger=E2=80=99s relentless work on g= earboxes.
>>>
>>> So there being evidence of failu= re outside of aircraft use, I'll look into another stronger starter rin= g gear.
>>>
>>> BUT more to the point. what experi= ence do we now have of removing the damper altogether?
>>> I th= ought this was the important question, because if not required, appears to = save significant: weight, cost, and maintenance.
>>>
>&g= t;> Has there been further word from Tracy or anyone else flying the RD2= or other no-isolator setups?
>>> Tracy=E2=80=99s initial testi= ng appeared promising but thats now some years back.
>>>
&g= t;>> Thanks heaps everyone. Couldn't have got this far without yo= ur brains, pain, cheque book, experience etc.
>>>
>>&= gt; Cheers
>>>
>>> Steve Izett
>>> >>>
>>>
>>>
>>>
>&g= t;>
>>>
>>>
>>>
>>>&= gt; On 7 Dec 2020, at 12:52 am, David Leonard wdleonard@gmail.com <flyrotary@lancaironline.net> wrote:
>>>>
>>>> Steve, you are right= .=C2=A0 The Issue is cracking og the auto-tranny flex plate.=C2=A0 Mine fai= led entirely.=C2=A0 I highly recommend making the change sooner rather than= later.
>>>>
>>>> Dave Leonard
>>&g= t;>
>>>> On Sun, Dec 6, 2020, 12:48 AM Stephen Izett stephen.izett@gma= il.com <flyrotary@lancaironline.net> wrote:
>>>> Hi Char= lie
>>>>
>>>> I thought people moved to the = race flywheels because the flex plates were cracking.
>>>> I= hadn=E2=80=99t heard of the Engine/Drive/Prop needing a flywheel mass.
= >>>> I found some info on the forum archive but nothing to draw= it all together.
>>>> I=E2=80=99ll have a good look at the = flexplate when I pull the drive and check for cracking, but unless I hear o= therwise I plan to reuse the flex plate.
>>>>
>>&g= t;> Thanks
>>>>
>>>> Steve
>>>= ;>
>>>>
>>>>
>>>>
&g= t;>>>
>>>>
>>>>> On 6 Dec 2020,= at 8:58 am, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:>>>>>
>>>>> On 12/5/2020 6:35 PM, Steph= en Izett steph= en.izett@gmail.com wrote:
>>>>>> Hi team
>&g= t;>>>>
>>>>>> Having completed phase #1 t= esting of the Glasair Super IIRG power by Renesis and RD1-C redrive, I=E2= =80=99re going to pull the redrive for its 25 hourly initial inspection.>>>>>>
>>>>>> Tracy deleted the da= mper assembly from the last rendition of his design and I=E2=80=99m conside= ring removing ours by creating a new adapter plate from the existing spline= d
>>>>>> part that is currently riveted to the damper = and adding some longer bolts and spacers.
>>>>>>
&= gt;>>>>> Has anyone heard anything further in regard to RD r= eceives with the damper removed?
>>>>>> Has Tracy give= n any further updatess?
>>>>>> All I have read was aft= er initial tests some years ago.
>>>>>>
>>&g= t;>>> Cheers
>>>>>>
>>>>>&= gt; Steve.
>>>>> Best I remember is that you need either = an aluminum or steel racing flywheel, to get more mass on the engine side o= f the system.=C2=A0 IIRC, it's also limited to low mass (wood, etc) pro= pellers. The ones he sold had a different input shaft, but I think Dave Leo= nard modified his RD1-C & to use a steel racing flywheel which was only= slightly heavier than the aluminum version. Search for Dave's posts, i= f he doesn't chime in. I've been wondering if Guibo/Rototflex coupl= ers could be a viable alternative to the aluminum plate/rubber discs. Proba= bly would weigh more, and definitely cost more.
>>>>> >>>>> Charlie
= FWIW, in the car, t= he torque converter seems to be bolted to the flexplate using the same hole= s that Tracy's adapter uses. Looking at the RX8 service manual, there m= ay be a narrow sheet metal adapter ring between the flex plate bolt circle = and the torque converter, but not much else in the way of structural reinfo= rcement. (Of course, the torque converter housing itself may act as stiffen= er.) It *seems* logical to me that if there were going to be stress cracks = caused by flying the assembly, they'd show up in the aluminum adapter p= late before the steel=C2=A0flex plate. And cracking usually starts where there's a = 'stress riser'; a notch or deep scratch in an edge. The only plates= I've observed have un-dressed, sharp edged punched holes where the cra= cks seem to originate. I don't know whether it will help, but I attacke= d my uncracked flex plate with a die grinder & files to clean up all th= e accessible edges of holes, etc, as we do with any aluminum parts, before = assembling everything.

Again, just my opinion, but I think that the real b= enefit of the extra mass of a flywheel is pulse isolation from the gearbox.=
<= br>
Charlie
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