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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. There 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 completely.
>
> 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 plate. The flex plate was just used to start the engine and nothing else. I turned 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 and the car sounded like a Brush Hog running over a pile of hammer heads. That 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 driving the wheels and the wheels are not driving the engine. Maybe as on final you 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 his mind about the need for the "higher frequency” 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 “flexing” forces at play.
> Steve Boese’ science/engineering mind or Lynn Hanover’s hands dirty experience appreciated at this point!
>
> Thanks also to Dave Leonard for what we have learnt from your need for speed, and Neil Unger’s 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’s 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
>
>
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>
> > 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 sooner 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’t 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’ll 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’re 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’m considering removing ours by creating a new adapter plate from the existing splined
> > >> part that is currently riveted to the damper and adding some longer bolts and spacers.
> > >>
> > >> Has anyone heard anything further in regard to RD receives with the 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 use 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 the aluminum plate/rubber discs. Probably would weigh more, and definitely cost more.
> > >
> > > Charlie
> > >
> > > --
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> > >
> > >
> > > --
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> >
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