X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m20.mx.aol.com ([64.12.137.1] verified) by logan.com (CommuniGate Pro SMTP 5.1.1) with ESMTP id 1505020 for flyrotary@lancaironline.net; Thu, 26 Oct 2006 00:44:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.1; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m20.mx.aol.com (mail_out_v38_r7.6.) id q.cc7.12926f0 (43930) for ; Thu, 26 Oct 2006 00:44:18 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Thu, 26 Oct 2006 00:44:18 EDT Subject: Re: [FlyRotary] Re: Flywheel machining and minimum inertia To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1161837858" X-Mailer: 9.0 Security Edition for Windows sub 5331 X-Spam-Flag: NO -------------------------------1161837858 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 10/25/2006 10:28:41 A.M. Eastern Daylight Time, echristley@nc.rr.com writes: cbeazley wrote: > Hi Again; > > Can a stock cast iron? flywheel be machined/lightened? > Are there any material problems other than standard > strength/thickness/balance? > > Does anyone, Lynn?, have any comments regarding the minimum flywheel > inertia > in order to provide a stable idle and minimize the effects of torque > pulses? > > I've seen lightened flywheels advertised on some of the racing shop sites, but boy are they expensive. -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | I have lightened many flywheels for race cars and never had a problem. It never occurred to me to try it on a rotary. The rotary has no reversals like a 4 cylinder piston engines, but has two powerful accelerations per revolution. There is no aircraft application for the stock flywheel lightened or otherwise. First of course is the unbelievable weight of the stock unit. The counterweight is cast into it and it would take a month of machine time to reduce it nearly any amount. In racing there is no need at all for a flywheel. Just a low ground clearance Chevy button flywheel and a 5 1/2" Tilton 2 disc clutch. Under 5 pounds for everything. Many flyers have notice that awful rattling sound when the idle is reduced too far. Those are the sounds of the gear box loaded in acceleration then when the crank slows as the next rotor goes into compression, the crank slows and the gear lash stacks up in opposition. Makes you jump the first (every) time you hear it. The race car does it to the big strong road racing transmission. There are many gears involved, and it is loud. The driver always thought it was some terminal sound, and the weekend was over. Just bump the idle speed up a bit and it is gone. You might get a taste on shutdown. The amount of energy you can store in a flywheel is a function of its mass among other things. Once at Indianapolis Racway park a bunch of RX-3s were coming onto the long straight when a big chunk of car went straight up in the air. The cowl, windshield, part of the rugs and floor board, and the transmission. All on the track. Half of the flywheel was stuck into the track. Trans oil everywhere. So there was a long cleanup. The car was toast. Lots of damage. Too many revs before a shift. Then there were few aftermarket flywheels available, and some people actually lightened the stock wheel. The drivers feet are behind the bellhousing so rotaries need not run a scatter-shield. I don't have one on the new car. But the flywheel and clutch are so small in diameter and lack the mass to store much energy. Plus, the rev limiter stops it at 9,600 RPM. A rotary with no load can attain astounding RPM in the flick of a throttle cable. Never stand in the plane of the flywheel. A automatic counterweight and a flex plate are just fine. A single rotor is a different deal. The more mass the better. Lynn E. Hanover -------------------------------1161837858 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 10/25/2006 10:28:41 A.M. Eastern Daylight Time,=20 echristley@nc.rr.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>cbeazley=20 wrote:

> Hi Again;
>
> Can a stock cast iron? flywhe= el=20 be machined/lightened?
> Are there any material problems other than=20 standard
> strength/thickness/balance?
>
> Does anyone,= =20 Lynn?, have any comments regarding the minimum flywheel
>=20 inertia
> in order to provide a stable idle and minimize the effects= of=20 torque
> pulses?
>
>
I've seen lightened flywheels=20 advertised on some of the racing shop
sites, but boy are they=20 expensive.

--
         ,|"|"|, =20             Ernest Christley   =20    |
----=3D=3D=3D<{{(oQo)}}>=3D=3D=3D----   = Dyke Delta=20 Builder      |
        o|  d&nb= sp;=20 |o        http://ernest.isa-geek.org =20 |
 
 
I have lightened many flywheels for race cars and never had a problem.=20= It=20 never occurred to me to try it on a rotary. The rotary has no reversals like= a 4=20 cylinder piston engines, but has two powerful accelerations per revolution.=20 There is no aircraft application for the stock flywheel lightened or otherwi= se.=20 First of course is the unbelievable weight of the stock unit.
 
The counterweight is cast into it and it would take a month of machine=20= time=20 to reduce it nearly any amount. In racing there is no need at all for a=20 flywheel. Just a low ground clearance Chevy button flywheel and a 5 1/2" Til= ton=20 2 disc clutch. Under 5 pounds for everything. Many flyers have notice that a= wful=20 rattling sound when the idle is reduced too far.
 
Those are the sounds of the gear box loaded in acceleration then when t= he=20 crank slows as the next rotor goes into compression, the crank slows and the= =20 gear lash stacks up in opposition. Makes you jump the first (every) time you= =20 hear it. The race car does it to the big strong road racing transmission. Th= ere=20 are many gears involved, and it is loud. The driver always thought it was so= me=20 terminal sound, and the weekend was over. Just bump the idle speed up a= bit=20 and it is gone. You might get a taste on shutdown.
 
The amount of energy you can store in a flywheel is a function of its m= ass=20 among other things. Once at Indianapolis Racway park a bunch of RX-3s were=20 coming onto the long straight when a big chunk of car went straight up in th= e=20 air. The cowl, windshield, part of the rugs and floor board, and the=20 transmission. All on the track. Half of the flywheel was stuck into the trac= k.=20 Trans oil everywhere. So there was a long cleanup. The car was toast. Lots o= f=20 damage. Too many revs before a shift.
 
Then there were few aftermarket flywheels available, and some people=20 actually lightened the stock wheel. The drivers feet are behind the=20 bellhousing so rotaries need not run a scatter-shield. I don't have one=20 on the new car. But the flywheel and clutch are so small in diameter an= d=20 lack the mass to store much energy. Plus, the rev limiter stops it at 9,600=20 RPM.
 
A rotary with no load can attain astounding RPM in the flick of a throt= tle=20 cable. Never stand in the plane of the flywheel. A automatic counterweight a= nd a=20 flex plate are just fine.
 
A single rotor is a different deal. The more mass the better.
 
Lynn E. Hanover
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