X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail18.syd.optusnet.com.au ([211.29.132.199] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTPS id 934877 for flyrotary@lancaironline.net; Fri, 20 Jan 2006 17:30:53 -0500 Received-SPF: none receiver=logan.com; client-ip=211.29.132.199; envelope-from=lendich@optusnet.com.au Received: from george (d220-237-232-68.dsl.nsw.optusnet.com.au [220.237.232.68]) by mail18.syd.optusnet.com.au (8.12.11/8.12.11) with SMTP id k0KMTxWG000967 for ; Sat, 21 Jan 2006 09:30:03 +1100 Message-ID: <00c001c61e11$10b284d0$44e8eddc@george> From: "george lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: flywheel weight? Date: Sat, 21 Jan 2006 08:30:05 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00BD_01C61E64.E154C5F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_00BD_01C61E64.E154C5F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageRusty, The manual flywheels do in fact replace the flexplate and balance. It would be difficult to know exactly how the balance was done in the = first place, what rotating weight were used and how were they modified. You could take off the flexplate and weight and try a flywheel, it won't = be right but it may give you some indication of the effectiveness of = smoothing out the torque pulses. George ( down under) 10lbs. That is about the weight of a rotor. But you'll be spinning = it 3 times as fast, so it'll have 8 times the momentum (momentum is velocity squared, right?). The object is to keep the shaft from speeding up and slowing down, and I think increasing the momentum 8 times would accomplish that well. Hi Ernest, All WAG's appreciated. I'm not sure the biggest problem is the = missing mass of the 2nd rotor, but rather the missing firing pulse. If = we were to continue your momentum thought though, the flywheel advantage = would be even greater than you suggested. Remember that the center of = the rotor mass is traveling in a much smaller radius circle than the = mass of the flywheel ring that I proposed. Heck, maybe that 1.5 lbs of = weight that I had before would have made up for the missing rotor :-) other ideas: Have the disc water/laser cut. And you don't need 4130, so have the cutter use whatever steel they have on hand. Have a brake shop turn the disc and balance it, or you might just be able to get a brake rotor that would bolt right into place with little or no modification. The heavy duty Matco rotors I just bought seem to be around those dimensions if memory serves. Interesting thoughts. I'm still leaning toward trying to install 4 = separate weights, which makes it possible to do this without pulling the = drive off. It also makes balancing a simple matter of precisely = weighing the added weights. I can buy 1/2" steel discs in various = diameters from McMaster Carr, so I would just have to drill a hole in = the middle, and bolt them on. I wonder what the limit of a 7/16" bolt = is for holding a couple pound weight spinning at 8000 rpm. Probably = don't want to have anything in the arc of the flex plate the first time = it was run up :-0 Dale, I thought about flywheels, but aren't they always manual trans = flywheels, made to install on the shaft itself? I need something that = coexists with the current auto balance weight, flex plate, and Tracy's = dampener plate. =20 Thanks, Rusty (trying hopelessly to resist) PS- Congrats to Joe! If this keeps up, people are going to think that = rotaries can only fly backwards :-) ------=_NextPart_000_00BD_01C61E64.E154C5F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Rusty,
The manual flywheels do in fact replace = the=20 flexplate and balance.
It would be difficult to know exactly = how the=20 balance was done in the first place, what rotating weight were used and = how were=20 they modified.
You could take off the flexplate and = weight and try=20 a flywheel, it won't be right but it may give you some indication of the = effectiveness of smoothing out the torque pulses.
George ( down under)

10lbs.  That is about the weight of a = rotor.  But=20 you'll be spinning it
3 times as fast, so it'll have 8 times the = momentum=20 (momentum is
velocity squared, right?).  The object is to keep = the=20 shaft from
speeding up and slowing down, and I think increasing the = momentum 8
times would accomplish that well.

Hi=20 Ernest,
 
All = WAG's=20 appreciated.  I'm not sure the biggest problem is the missing = mass of the=20 2nd rotor, but rather the missing firing pulse.  If we were to = continue=20 your momentum thought though, the flywheel advantage would be = even=20 greater than you suggested.  Remember that the center of the=20 rotor mass is traveling in a much smaller radius circle than = the=20 mass of the flywheel ring that I proposed.  Heck, maybe that 1.5 = lbs of=20 weight that I had before would have made up for the missing = rotor=20 :-)
 
other ideas:  Have the disc water/laser = cut.  And=20 you don't need 4130,
so have the cutter use whatever steel they = have on=20 hand.  Have a brake
shop turn the disc and balance it, or you = might=20 just be able to get a
brake rotor that would bolt right into place = with=20 little or no
modification.  The heavy duty Matco rotors I just = bought=20 seem to be
around those dimensions if memory serves.
 
Interesting=20 thoughts.  I'm still leaning toward trying to install 4 separate = weights,=20 which makes it possible to do this without pulling the drive = off.  It=20 also makes balancing a simple matter of precisely weighing the added=20 weights.  I can buy 1/2" steel discs in various diameters from = McMaster=20 Carr, so I would just have to drill a hole in the middle, and bolt = them=20 on.  I wonder what the limit of a 7/16" bolt is for holding a=20 couple pound weight spinning at 8000 rpm.  Probably = don't want=20 to have anything in the arc of the flex plate the first = time it was=20 run up :-0
 
Dale,
 
I = thought about=20 flywheels, but aren't they always manual trans flywheels, made to = install on=20 the shaft itself?  I need something that coexists with the=20 current auto balance weight, flex plate, and Tracy's dampener=20 plate.  
 
Thanks,
Rusty (trying hopelessly to=20 resist)
 
PS- Congrats to Joe!  If = this keeps=20 up, people are going to think that rotaries can only fly backwards=20 :-)
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