From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] RD1-C damper
Date: Mon, 7 Dec 2020 06:27:57 +0800
References: <list-1014352@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-1014352@logan.com>
Message-Id: <F3F4BB91-FCD9-480B-B25E-4159970E0E49@gmail.com>

Thanks Dave.=20

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=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 for =
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.=20

Thanks heaps everyone. Couldn't have got this far without your brains, =
pain, cheque book, experience etc.

Cheers

Steve Izett


=20


> On 7 Dec 2020, at 12:52 am, David Leonard wdleonard@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> 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.
>=20
> Dave Leonard
>=20
> On Sun, Dec 6, 2020, 12:48 AM Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
> Hi Charlie
>=20
> I thought people moved to the race flywheels because the flex plates =
were cracking.=20
> 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 otherwise I plan to reuse the =
flex plate.
>=20
> Thanks
>=20
> Steve
>=20
>=20
>=20
>=20
>=20
>=20
> > On 6 Dec 2020, at 8:58 am, Charlie England ceengland7@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >=20
> > On 12/5/2020 6:35 PM, Stephen Izett stephen.izett@gmail.com wrote:
> >> Hi team
> >>=20
> >> 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.
> >>=20
> >> Tracy deleted the damper assembly from the last rendition of his =
design and I=E2=80=99m 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.
> >>=20
> >> 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.
> >>=20
> >> Cheers
> >>=20
> >> 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.
> >=20
> > Charlie
> >=20
> > --=20
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> >=20
> >=20
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>=20
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