X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao101.cox.net ([68.230.241.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4178976 for flyrotary@lancaironline.net; Thu, 25 Mar 2010 18:26:46 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.45; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao101.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20100325222611.VJQD5695.fed1rmmtao101.cox.net@fed1rmimpo03.cox.net> for ; Thu, 25 Mar 2010 18:26:11 -0400 Received: from BigAl ([72.192.128.205]) by fed1rmimpo03.cox.net with bizsmtp id xaSA1d00T4S1t5C04aSAYr; Thu, 25 Mar 2010 18:26:11 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=yjuDh3Ma92GrVaJxYD7gfORM7ilP1Knqouyx6SOEBcg= c=1 sm=1 a=mCYC60vsq5EA:10 a=Vegc0WxVmH5BHtpNDyThtA==:17 a=Ia-xEzejAAAA:8 a=XyM3u0tVAAAA:8 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=f4jGXqvpAAAA:8 a=kviXuzpPAAAA:8 a=nUuTZ29dAAAA:8 a=n1tfoQGmKaUUjGJn6L4A:9 a=YmmQgP_g9etLQLAKOjUA:7 a=ePoLa8ofSeEROAY-BnJgobvVO6QA:4 a=wPNLvfGTeEIA:10 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=4vB-4DCPJfMA:10 a=7oRDrAS2mtNcGFzI:21 a=m5fZeYkMW5ugiy8e:21 a=nXdirnbjtmE1qFTG-6wA:9 a=hyhjrtCq2KsAToqC_-0A:7 a=6RXoMbd6NDTlrSFqw_vKeaQ0VS0A:4 a=zPJ7LOrOauv-LWEw:21 a=bs_jcx5CYPOZZoeB:21 a=Vegc0WxVmH5BHtpNDyThtA==:117 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate rivets Date: Thu, 25 Mar 2010 15:25:59 -0800 Message-ID: <197B578BD34C4045BE84478228DA7E10@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01CACC2F.78C228C0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6856 In-Reply-To: Importance: Normal Thread-Index: AcrMTsUcJ0JH5S8rQgSLcO5chgy9ogAIzaIg X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0013_01CACC2F.78C228C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable One never knows for sure; but I think not likely that this applies. = This is for discs constrained at the center, as on a spindle, where the outer = edge is free. In our case we have 4 big bolts and square pads constraining = the outer edge. Not to mention relatively low rotational speeds and thick = discs. =20 Al =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Thursday, March 25, 2010 11:09 AM To: Rotary motors in aircraft Subject: [FlyRotary] Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate rivets =20 Actually, this model might be closer to our disc on a shaft gearbox =20 http://www.mecheng.osu.edu/vibrations/files/vibrations/jva7-99b.pdf =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Thursday, March 25, 2010 3:03 PM To: Rotary motors in aircraft Subject: [FlyRotary] Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate rivets =20 Have not gone out and checked my rivets on my R1C, will do that this weekend. However, there is one possibility for the cause of the smoking rivets that I have not heard addressed and that is vibration nodes of a rotating disc. There is the possibility that if the disc were in some oscillatory mode that the smoking rivets might be caused by with the = rivets being at the nodes of certain modes (like that?) of vibration which = could be causing the holes in the discs to be sliding up and down the shaft of rivet. =20 In the end, it may be important to know what is causing this. The 20Bs should be smoother than the 13Bs, on the other hand, they do have a different firing frequency. For the same RPM the number of firing = pulses from the 20B are 1/3 higher than the 13B over the same time period. = That could possibly induce vibration nodes in the disc that the 13B (which = has longer duration between firings pulses). The long time between firings = in the 13B might permit the mass/structure of the assembly to dampen the amplitude of any such induced vibration between firings pulses =96 = where not so for the more frequent pulses of the 20B. The higher the frequency = of the input, the stiffer structure that can be caused to vibrate. A vast = over simplification, but thought I would throw it out just incase somebody = had a finite analysis package sitting on their computer. Just a WAG. =20 Here is an URL that provides a drawing of how such nodes might form on a disc =20 http://demonstrations.wolfram.com/NormalOscillatoryModesOfRotatingOrthotr= opi cDisks/ =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle Sent: Thursday, March 25, 2010 2:25 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Adaptor plate rivets =20 Al, =20 I had a bunch of AN-6A bolts, so I used them with two thick washers, one under the head and one under the nut. I mainly wanted to ensure that = the shank went all the way through both pieces. You might be able to use AN-5.5A or even AN-5A bolts if you use only one thin washer under the = nut. =20 =20 Mark S. =20 On Thu, Mar 25, 2010 at 11:22 AM, Al Gietzen wrote: To answer your question about the washers, I used thick washers on both sides. But I'll have to remove them all in order to replace the AN-6A = bolts with AN173-6A's. I'm hoping the bolts arrive by this weekend so I can = start putting everything back together. =20 Normally washers are needed only under the side that you=92re turning to = apply the force; unless needed to provide shimming or a more uniform or larger surface. The -6A length has a 3/8=94 grip length, and I assumed the = plate was 1/8=94 and the flange =BC=94. If the thickness is less I may have to = get some more, or thicker, washers. =20 Al =20 __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0013_01CACC2F.78C228C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

One never knows for sure; but I = think not likely that this applies.=A0 This is for discs constrained at the = center, as on a spindle, where the outer edge is free.=A0 In our case we have 4 big = bolts and square pads constraining the outer edge. Not to mention relatively = low rotational speeds and thick discs.

 

Al

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Thursday, March 25, = 2010 11:09 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] = Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate = rivets

 

Actually, this = model might be closer to our disc on a shaft gearbox

 

http://www.mecheng.osu.edu/vibrations/files/vibrations/jva7-99b.pdf

 

Ed<= /p>

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Thursday, March 25, = 2010 3:03 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] = Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate = rivets

 

Have not gone = out and checked my rivets on my R1C, will do that this weekend.  However, = there is one possibility for the cause of the smoking rivets that I have not = heard addressed and that is vibration nodes of a rotating disc.  There is the = possibility that if the disc were in some oscillatory mode that the smoking rivets = might be caused by with the rivets  being at the nodes of certain modes = (like that?) of vibration which could be causing the holes in the discs to be = sliding up and down the shaft of  rivet.

 

In the end, it = may be important to know what is causing this.  The 20Bs should be = smoother than the 13Bs, on the other hand, they do have a different firing = frequency.  For the same RPM the number of firing pulses from the 20B are 1/3 higher = than the 13B over the same time period.   That could possibly = induce vibration nodes in the disc that the 13B (which has longer duration = between firings pulses).  The long time between firings in the 13B might = permit the mass/structure of the assembly to dampen the amplitude of any such = induced vibration  between firings pulses – where  not so for = the more frequent pulses of the 20B.   The higher the frequency of the = input, the stiffer structure that can be caused to vibrate.  A vast over simplification, but thought I would throw it out just incase somebody = had a finite analysis package sitting on their computer.  =   Just a WAG.

 

Here is an URL = that provides a drawing of how such nodes might form on a = disc

 

http://demonstrations.wolfram.com/NormalOscillatoryMo= desOfRotatingOrthotropicDisks/

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Thursday, March 25, = 2010 2:25 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = Adaptor plate rivets

 

Al,

 

I had a bunch of AN-6A bolts, so I used them = with two thick washers, one under the head and one under the nut.  I mainly = wanted to ensure that the shank went all the way through both pieces.  You = might be able to use AN-5.5A or even AN-5A bolts if you use only one thin = washer under the nut.  

 

Mark S.

 

On Thu, Mar 25, 2010 at 11:22 AM, Al Gietzen = <ALVentures@cox.net> = wrote:

To answer your question about the washers, I = used thick washers on both sides.  But I'll have to remove them all in order = to replace the AN-6A bolts with AN173-6A's.  I'm hoping the bolts = arrive by this weekend so I can start putting everything back together. =  

Normally washers are needed only under the side that you’re turning to = apply the force; unless needed to provide shimming or a more uniform or larger surface.  The -6A length has a 3/8” grip length, and I = assumed the plate was 1/8” and the flange =BC”.  If the thickness = is less I may have to get some more, or thicker, washers.

 

Al

 



__________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

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