X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ww0-f50.google.com ([74.125.82.50] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTPS id 5050862 for flyrotary@lancaironline.net; Wed, 13 Jul 2011 15:36:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.50; envelope-from=rwstracy@gmail.com Received: by wwe6 with SMTP id 6so4934359wwe.7 for ; Wed, 13 Jul 2011 12:35:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=lFSDKAjxwW1D5iHil9Jb26Qw59V1uRMhM+HTrpMlKTE=; b=jsdtOoCxvmwwwhiA2BN9sg2WUosUqKvMUXhLXy4Sp/j4OLmyCgSXDrh+4m/X4jWQyD MKMx4mPXaAVcHemJiSndEg+Svust5oRW4SDwwhxVJvsDKTp86k8Sp2wKyOoCPNwF88+f 3tkczLU9inELz/Ceb1/E9wcCX0oQByJOSMeWk= MIME-Version: 1.0 Received: by 10.216.78.144 with SMTP id g16mr1255136wee.64.1310585734565; Wed, 13 Jul 2011 12:35:34 -0700 (PDT) Received: by 10.216.90.205 with HTTP; Wed, 13 Jul 2011 12:35:34 -0700 (PDT) In-Reply-To: References: Date: Wed, 13 Jul 2011 15:35:34 -0400 Message-ID: Subject: Re: [FlyRotary] Re: RD-1B failure From: Tracy To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000e0ce0ce08280edc04a7f885f1 --000e0ce0ce08280edc04a7f885f1 Content-Type: text/plain; charset=ISO-8859-1 This same failure occurred on many Blanton V6 conversions where the flexplate was used solely to engage the starter bendix. I don't think this is likely with the RD-1x where the flexplate is bolted to the damper assembly unless the flexplate is warped or damaged. I have well over 1000 hours on a single flexplate with no signs of deterioration. But this is experimental stuff and even 1000 hours is not a guarantee. Tracy On Wed, Jul 13, 2011 at 2:40 PM, Richard Sohn wrote: > ** > 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. > > 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. > > Richard Sohn > N2071U > www.fairpoint.net/~res12/home.html > > ----- Original Message ----- > *From:* Al Wick > *To:* Rotary motors in aircraft > *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. > > 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. > > 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. > > -Al Wick > Cozy IV powered by Turbo Subaru 3.0R. > 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 ----- > > *From:* hoursaway1@comcast.net > *To:* Rotary motors in aircraft > *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 ??? > -- > 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 > > --000e0ce0ce08280edc04a7f885f1 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable This same failure occurred on many Blanton V6 conversions where the flexpla= te was used solely to engage the starter bendix.=A0=A0 I don't think th= is is likely with the RD-1x=A0 where the flexplate is bolted to the damper = assembly unless the flexplate is warped or damaged. =A0 I have well over 10= 00 hours on a single flexplate with no signs of deterioration. =A0 But this= is experimental stuff and even 1000 hours is not a guarantee.

Tracy
=A0

On Wed, Jul 13, 2011 at = 2:40 PM, Richard Sohn <res12@fairpoint.net> wrote:
I lost my confidence in using a flexpl= ate about 8=20 years ago. I used it on my EA81 as a flywheel only. after about 45hrs flyin= g=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 cra= cks=20 showed all the symptoms of material fatigue. It obviously was experiencing= =20 flexmodes and possibly resonances without sufficient damping in the RPM ran= ge it=20 was used in. Any of that flexing does not happen when attached to a torque= =20 converter.
First=A0I tried an AL flywheel, which = did not=20 give me enough inertia for satisfactory idle.=A0A steel flywheel weighing= =20 about 6lb did the trick. Never had a problem again.
FWIW.=A0
=A0
----- 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 di= d=20 measurements and analysis of the Lou Ross, then some experiments to prove= =20 cause and effect. Here's what I learned:
=A0
The drive plate has tremendous stren= gth in the=20 rotational axis, but very susceptible to fore/aft movement. All of the cr= acks=20 are consistent with fatigue failure fore aft direction. In addition, the = Lou=20 Ross had=A0symptoms 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, th= at was=20 proof of 1/4" movement. In addition, this movement rapidly caused gr= ease 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 ha= ve these=20 same predictors, but I thought it was valuable to explain all of the=20 supporting evidence.
=A0
Fuel combustion causes explosion whi= ch sends high=20 energy pulse to drive train. Since the gears are helical, a portion of th= at=20 energy is transferred into fore aft movement of the input shaft. Excessiv= e=20 clearance at the end of that shaft allows greater inertia of shaft. Beati= ng 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 th= at=20 little pilot bushing. No more wide wear pattern on the input shaft spline= . No=20 more failure risk.
=A0
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/Page40= 4.htm
=A0
I think you guys are using a pretty = good psru.=20 Very likely you have this same problem.
=A0
-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 assess= ment=20 info:
http://www.maddyhome.com/canardpages/pages/alwic= k/index.html
=A0
=A0
=A0
----- Original Message -----
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,=A0 on cars that someone had removed trans & did not reinstal= l=20 all the retaining bolts, improper alignment of trans/eng., guide pin=20 missing, trans bolts loose, damaged when trans installed (pry bar nicks= all=20 over the flywheel caused cracks) found a rag installed between trans &a= mp;=20 eng., & also on NEW cars with low miles no previous repairs=20 performed.=A0=A0=A0=A0=A0=A0=A0=A0 I also found=20 three Mazda auto trans flywheels as Tracy did, with very fine cracks ar= ound=20 the lightening holes ( not the bolt holes )=A0 when we were looking for= =20 one to use on our RV6A=A0rotary.=A0 I even asked the salvage yard guy= =20 to check for me & he missed them & shipped me that junk=20 flywheel.=A0=A0=A0=A0=A0 =A0=A0 David R. Cook=A0=20 RV6A Rotary,=A0 Lansing MI.

From: "David Leonard" <wdleonard@gmail.com>
To:=20 "Rotary motors in aircraft"=20 <fl= yrotary@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=A0 ???
--
David= =20 Leonard

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

--
Homepage:=20 =A0http://www.f= lyrotary.com/
Archive and UnSub: =A0=20 http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l

--000e0ce0ce08280edc04a7f885f1--