X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp1.av-mx.com ([137.118.16.57] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5050777 for flyrotary@lancaironline.net; Wed, 13 Jul 2011 14:40:59 -0400 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.57; envelope-from=res12@fairpoint.net Received: from main (dflo-66-243-231-69.gtcom.net [66.243.231.69]) (Authenticated sender: res12@fairpoint.net) by smtp1.av-mx.com (Postfix) with ESMTP id 2738E2925FE for ; Wed, 13 Jul 2011 14:40:22 -0400 (EDT) Message-ID: <736F4FF4411047B8B93A1B73FCE327E8@main> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: RD-1B failure Date: Wed, 13 Jul 2011 13:40:40 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0059_01CC4162.745798C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6109 This is a multi-part message in MIME format. ------=_NextPart_000_0059_01CC4162.745798C0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I lost my confidence in using a flexplate about 8 years ago. I used it = on my EA81 as a flywheel only. after about 45hrs flying time I found = some scraping of the ring gear on the redrive mounting plate. It turned = out to be cracked in a similar way shown and described here. The cracks = showed all the symptoms of material fatigue. It obviously was = experiencing flexmodes and possibly resonances without sufficient = damping in the RPM range it was used in. Any of that flexing does not = happen when attached to a torque converter.=20 First I tried an AL flywheel, which did not give me enough inertia for = satisfactory idle. A steel flywheel weighing about 6lb did the trick. = Never had a problem again. FWIW.=20 Richard Sohn N2071U www.fairpoint.net/~res12/home.html ----- Original Message -----=20 From: Al Wick=20 To: Rotary motors in aircraft=20 Sent: Wednesday, July 13, 2011 8:30 AM Subject: [FlyRotary] Re: RD-1B failure There's a lot of history of this type of drive plate failure. It = occurred on the Lou Ross psru with some frequency. I did measurements = and analysis of the Lou Ross, then some experiments to prove cause and = effect. Here's what I learned: The drive plate has tremendous strength in the rotational axis, but = very susceptible to fore/aft movement. All of the cracks are consistent = with fatigue failure fore aft direction. In addition, the Lou Ross had = symptoms which forecast drive plate risk. The width of the spline wear = on the input shaft was a direct measure of how far the shaft moves fore = aft. So if the spline on the drive plate had 1" of contact with the = mating spline, yet you saw spline wear on shaft to be 1.25" wide, that = was proof of 1/4" movement. In addition, this movement rapidly caused = grease to be extruded from the little pilot bearing at the end of the = input shaft. So you'd see grease streaks after only 5 hours of use. = Looks like you don't have these same predictors, but I thought it was = valuable to explain all of the supporting evidence.=20 Fuel combustion causes explosion which sends high energy pulse to = drive train. Since the gears are helical, a portion of that energy is = transferred into fore aft movement of the input shaft. Excessive = clearance at the end of that shaft allows greater inertia of shaft. = Beating on drive plate like a hammer. The input shaft is steel, the psru = housing is aluminum. They don't expand the same amount when heated. As a = result, the Ross psru had excessive clearance during operation. Getting = rid of this excess clearance dramatically improved Ross design. No more = loss of grease on that little pilot bushing. No more wide wear pattern = on the input shaft spline. No more failure risk.=20 I also came up with this wild idea I could have zero clearance at end = of input shaft. I tried it and surprise, it worked. I called it a "cage = cap". See my web site. = http://www.maddyhome.com/canardpages/pages/alwick/index_files/Page404.htm= I think you guys are using a pretty good psru. Very likely you have = this same problem.=20 -Al Wick Cozy IV powered by Turbo Subaru 3.0R.=20 Computer monitoring improves safety, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ----- Original Message -----=20 From: hoursaway1@comcast.net=20 To: Rotary motors in aircraft=20 Sent: Tuesday, July 12, 2011 4:17 PM Subject: [FlyRotary] Re: RD-1B failure David, I have seen this multiple times in the auto repair business, = as far as a cause, on cars that someone had removed trans & did not = reinstall all the retaining bolts, improper alignment of trans/eng., = guide pin missing, trans bolts loose, damaged when trans installed (pry = bar nicks all over the flywheel caused cracks) found a rag installed = between trans & eng., & also on NEW cars with low miles no previous = repairs performed. I also found three Mazda auto trans flywheels = as Tracy did, with very fine cracks around the lightening holes ( not = the bolt holes ) when we were looking for one to use on our RV6A = rotary. I even asked the salvage yard guy to check for me & he missed = them & shipped me that junk flywheel. David R. Cook RV6A = Rotary, Lansing MI. -------------------------------------------------------------------------= --- From: "David Leonard" To: "Rotary motors in aircraft" Sent: Tuesday, July 12, 2011 6:27:57 PM Subject: [FlyRotary] Re: RD-1B failure Left over pieces of flex plate - we being held together by ??? --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0059_01CC4162.745798C0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
I lost my confidence in using a = flexplate about 8=20 years ago. I used it on my EA81 as a flywheel only. after about 45hrs = flying=20 time I found some scraping of the ring gear on the redrive mounting = plate. It=20 turned out to be cracked in a similar way shown and described here. The = cracks=20 showed all the symptoms of material fatigue. It obviously was = experiencing=20 flexmodes and possibly resonances without sufficient damping in the RPM = range it=20 was used in. Any of that flexing does not happen when attached to a = torque=20 converter.
First I tried an AL flywheel, = which did not=20 give me enough inertia for satisfactory idle. A steel flywheel = weighing=20 about 6lb did the trick. Never had a problem again.
FWIW. 
 
Richard Sohn
N2071U
www.fairpoint.net/~res= 12/home.html
----- Original Message -----
From:=20 Al Wick =
Sent: Wednesday, July 13, 2011 = 8:30=20 AM
Subject: [FlyRotary] Re: RD-1B=20 failure

There's a lot of history of this type = of drive=20 plate failure. It occurred on the Lou Ross psru with some frequency. I = did=20 measurements and analysis of the Lou Ross, then some experiments to = prove=20 cause and effect. Here's what I learned:
 
The drive plate has tremendous = strength in the=20 rotational axis, but very susceptible to fore/aft movement. All of the = cracks=20 are consistent with fatigue failure fore aft direction. In addition, = the Lou=20 Ross had symptoms which forecast drive plate risk. The width of = the=20 spline wear on the input shaft was a direct measure of how far the = shaft moves=20 fore aft. So if the spline on the drive plate had 1" of contact with = the=20 mating spline, yet you saw spline wear on shaft to be 1.25" wide, that = was=20 proof of 1/4" movement. In addition, this movement rapidly caused = grease to be=20 extruded from the little pilot bearing at the end of the input shaft. = So you'd=20 see grease streaks after only 5 hours of use. Looks like you don't = have these=20 same predictors, but I thought it was valuable to explain all of the=20 supporting evidence.
 
Fuel combustion causes explosion = which sends high=20 energy pulse to drive train. Since the gears are helical, a portion of = that=20 energy is transferred into fore aft movement of the input shaft. = Excessive=20 clearance at the end of that shaft allows greater inertia of shaft. = Beating on=20 drive plate like a hammer. The input shaft is steel, the psru housing = is=20 aluminum. They don't expand the same amount when heated. As a result, = the Ross=20 psru had excessive clearance during operation. Getting rid of this = excess=20 clearance dramatically improved Ross design. No more loss of grease on = that=20 little pilot bushing. No more wide wear pattern on the input shaft = spline. No=20 more failure risk.
 
I also came up with this wild idea I = could have=20 zero clearance at end of input shaft. I tried it and surprise, it = worked. I=20 called it a "cage cap". See my web site. http://www.maddyhome.com/canardpages/pages/alwick/index_files/P= age404.htm
 
I think you guys are using a pretty = good psru.=20 Very likely you have this same problem.
 
-Al Wick
Cozy IV powered by Turbo = Subaru 3.0R.=20
Computer monitoring improves safety, N9032U 240+ hours from = Portland,=20 Oregon
Glass panel design, Subaru install, Prop construct, Risk = assessment=20 info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html
 
 
 
----- Original Message -----
From:=20 hoursaway1@comcast.net =
To: Rotary motors in = aircraft=20
Sent: Tuesday, July 12, 2011 = 4:17=20 PM
Subject: [FlyRotary] Re: = RD-1B=20 failure

David, I=20 have seen this multiple times in the auto repair business, as far as = a=20 cause,  on cars that someone had removed trans & did not = reinstall=20 all the retaining bolts, improper alignment of trans/eng., guide pin = missing, trans bolts loose, damaged when trans installed (pry bar = nicks all=20 over the flywheel caused cracks) found a rag installed between trans = &=20 eng., & also on NEW cars with low miles no previous repairs=20 performed.         I also = found=20 three Mazda auto trans flywheels as Tracy did, with very fine cracks = around=20 the lightening holes ( not the bolt holes )  when we were = looking for=20 one to use on our RV6A rotary.  I even asked the salvage = yard guy=20 to check for me & he missed them & shipped me that junk=20 flywheel.         David R. = Cook =20 RV6A Rotary,  Lansing MI.

From: "David Leonard" <wdleonard@gmail.com>
To:=20 "Rotary motors in aircraft"=20 <flyrotary@lancaironline.net>
Sent: Tuesday, July = 12, 2011=20 6:27:57 PM
Subject: [FlyRotary] Re: RD-1B = failure

Left over=20 pieces of flex plate - we being held together by  ???
-- =
David=20 Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

--
Homepage:=20  http://www.flyrotary.com/
Archive and UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html
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