X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp0.av-mx.com ([137.118.16.56] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3878248 for flyrotary@lancaironline.net; Wed, 07 Oct 2009 17:33:11 -0400 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.56; envelope-from=res12@fairpoint.net Received: from main (unknown [66.243.229.194]) (Authenticated sender: res12@fairpoint.net) by smtp0.av-mx.com (Postfix) with ESMTP id CA5CC1BFF0A for ; Wed, 7 Oct 2009 17:32:33 -0400 (EDT) Message-ID: <4C909A6AA61A4F8582A18489E5934104@main> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Balls and Springs Date: Wed, 7 Oct 2009 16:32:46 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0180_01CA476B.CD37F630" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0180_01CA476B.CD37F630 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi George, did you get my response to Lynn's comment at about 10:99this morning? It = is located down after what Lynn wrote. Sorry, some do it one way and = others the other way.=20 Richard Sohn N2071U ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 07, 2009 4:04 PM Subject: [FlyRotary] Re: Balls and Springs Lynn, Thanks, I have spun up the rotor in a lathe and filled the rotor with = coolant from a spray bottle, being careful not to spill any and then = weighing the remainder and comparing it to the original weight (similar = system to what you suggest). I went the extra mile and then adjusted the = weight by comparing it to oil weight of the same volume. I did speak to Richard Sohn at the time but at that stage he wasn't to = concerned with balancing to that extent with his demonstrator. It has also been suggested that the apex seal and springs be excluded = as their weight is borne by the rotor housing. Then again I've had people argue against those suggestions. I thought any out of balance might exacerbate the negative torque = pulses, but your saying because their so large it's not such a concern = - which puts my mind to rest. I do like your suggestion of 'reverse engineering' the balancing = process, I think I will discuss that with a professional balancer. George (down under) Lynn, With balancing my single rotor, what would you suggest that I allow = ( percentage wise) for oil weight in the rotor - it was suggested to me = that I should allow full rotor oil weight. This discussion suggests otherwise. George ( down under) George, The process I saw on the internet came from Down there. A rotor is = spun up in the lathe with a plastic shield around the outside. Oil is = squirted in until it starts spilling out. A pan is slipped under the = rotor and the lathe stopped. (if your lathe has a coolant system that = would work as well with less mess) The weights are close enough. Then = the rotor is laid on a grill on the pan and allowed to drain. Then weigh = the liquid in the pan. I bet the balancing people just have a number on = the wall for rotaries that is close to that weight. A balancer could do = it backwards by spinning the shaft from a factory built engine, with the = counterweights mounted, and then add bobweight until he gets a balance. = Then subtract the rotor weight from the bobweight and that difference = would be the oil allowance.=20 The big name builders all balance to a gnats butt weight, but I just = get the rotor weights the same. Never a problem. The single pulse per = revolution will be so big that a small balance error will go unoticed. = But, its no sin to start out with the balance correct. I have thought = about singles and decided that as big a diameter flywheel that you can = fit but weighted only at the outer edge. Like 4 sets of starter rings = tiged to a flex plate. Even Mazda builds with pieces two weight ranges = apart. They have stamped the weights on rotors, and have used colored = paint dots. Of course the paint dots are gone when we see a used rotor.=20 Richard Sohn can tell you. He seems to be doing well with his. Lynn E. Hanover -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG - www.avg.com=20 Version: 8.5.421 / Virus Database: 270.14.5/2419 - Release Date: = 10/07/09 05:18:00 ------=_NextPart_000_0180_01CA476B.CD37F630 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi George,
 
did you get my response to Lynn's = comment at about=20 10:99this morning? It is located down after what Lynn wrote. Sorry, some = do it=20 one way and others the other way.
 
Richard Sohn
N2071U
----- Original Message -----
From:=20 George=20 Lendich
Sent: Wednesday, October 07, = 2009 4:04=20 PM
Subject: [FlyRotary] Re: Balls = and=20 Springs

Lynn,
Thanks, I have spun up the rotor in a = lathe and=20 filled the rotor with coolant from a spray bottle, being careful not = to spill=20 any and then weighing the remainder and comparing it to the original = weight=20 (similar system to what you suggest). I went the extra mile and then = adjusted=20 the weight by comparing it to oil weight of the same = volume.
 
I did speak to Richard Sohn at the = time but at=20 that stage he wasn't to concerned with balancing to that extent with = his=20 demonstrator.
 
It has also been suggested that the = apex seal and=20 springs be excluded as their weight is borne by the rotor=20 housing.
 
Then again I've had people argue = against those=20 suggestions.
 
I thought any out of balance might = exacerbate the=20 negative torque pulses, but your saying because their so large it's = not =20 such a concern - which puts my mind to rest.
 
I do like your suggestion of  = 'reverse=20 engineering' the balancing process, I think I will discuss that with a = professional balancer.
 
George (down=20 under)
 Lynn,
With balancing my single rotor, what = would you=20 suggest that I allow ( percentage wise) for oil weight in the rotor = - it was=20 suggested to me that I should allow full rotor oil weight.
This discussion suggests = otherwise.
George ( down under)
 
George,
 
The = process I saw=20 on the internet came from Down there. A rotor is spun up in the = lathe with a=20 plastic shield around the outside. Oil is squirted in until it = starts=20 spilling out. A pan is slipped under the rotor and the lathe = stopped. (if=20 your lathe has a coolant system that would work as well with less = mess) The=20 weights are close enough. Then the rotor is laid on a grill on the = pan and=20 allowed to drain. Then weigh the liquid in the pan. I bet the = balancing=20 people just have a number on the wall for rotaries that is close to = that=20 weight. A balancer could do it backwards by spinning the shaft from = a=20 factory built engine, with the counterweights mounted, and then add=20 bobweight until he gets a balance. Then subtract the rotor weight = from the=20 bobweight and that difference would be the oil allowance.=20
 
The big = name=20 builders all balance to a gnats butt weight, but I just get the = rotor=20 weights the same. Never a problem. The single pulse per revolution = will be=20 so big that a small balance error will go unoticed. But, its no sin = to start=20 out with the balance correct. I have thought about singles and = decided that=20 as big a diameter flywheel that you can fit but weighted only at the = outer=20 edge. Like 4 sets of starter rings tiged to a flex plate. Even Mazda = builds=20 with pieces two weight ranges apart. They have stamped the weights = on=20 rotors, and have used colored paint dots. Of course the paint dots = are gone=20 when we see a used rotor.
 
Richard = Sohn can=20 tell you. He seems to be doing well with his.
 
Lynn E.=20 Hanover
 


No virus found in this incoming message.
Checked by AVG = -=20 www.avg.com
Version: 8.5.421 / Virus Database: 270.14.5/2419 - = Release=20 Date: 10/07/09 05:18:00
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