X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from mail-yb1-f172.google.com ([209.85.219.172] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 2654140 for flyrotary@lancaironline.net; Tue, 28 Nov 2023 10:28:05 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.172; envelope-from=wdleonard@gmail.com Received: by mail-yb1-f172.google.com with SMTP id 3f1490d57ef6-db3fa47c2f7so5026333276.0 for ; Tue, 28 Nov 2023 07:28:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701185268; x=1701790068; darn=lancaironline.net; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=exClb0xu2FDnD8GVdHBVbwOQoPwc7l0+fmkPHvMrpeA=; b=AGYNEbtDtz6fl3kkJt7bq5vBO0n7X+a6Y5w/l58syXfYQsL0kfljgGtHUgzOmCSUNN G+/T02LKXvh7fMN891avfPcOZ1QYny05utQlq2KjuZYSE5PIjI7V3+phVwC1gAbPrhHq jXWVrWnbJLQ523rnSocS2VaQV0EbFegGboMHKGYUemYO/1vJOhhQNWOdZzj50BNmfRnU lKekS5fpIrUPtwHiTNVRNdDQeCy34fuG/v8roySw8DcEOUMIwBJHR2rzUa/wVoZ8/FJF IEON0SkP4WOo3S5yh9snKKkDNPtMyJ/9r3MVfxVuYE2d8OfUQ4eYxB8lIR+rsikK8RI7 PBiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701185268; x=1701790068; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=exClb0xu2FDnD8GVdHBVbwOQoPwc7l0+fmkPHvMrpeA=; b=Lq8r7MCdZbSQ3Yv2CLKnZH5hFiMKM8xnE5sc/aRVvODXZzMSYlFVoWe/keRProJWhX vaXpP2bx+cMw6DxjGI060SAIP9w3C1C/eA7mijn47aRJ32QPBM0kIuYw6ZKt5Z0ZrlvS epaLbVRHjOuKKQH1m0tRv6ifopFoH3Tye+uJeFm2qEryPjCuB257p6gFiRb8//OAvjIn 8pPB7XmnntpZs5kfnrLA+Wg5z3e9zAcskeig7zCH1VzJb1o4crE7Pip1wku61ftnTcqf qmCF9FCJ+GxqnPJ0N1VVdkoDguwRszw0pfCqwxBjPI1N+oITIFDp2mEyLWIcMuYGl8SY mjTQ== X-Gm-Message-State: AOJu0YxH6bYNyvI3EKDWJ4KddvuvY5pFVnk9ikeLJZK2SQB2OxINilqy mZrcVHgAfFcl/hIH3zUKChECqpkRnd2iIh/at+xrmHv/yvs= X-Google-Smtp-Source: AGHT+IGB7YWytQb1qhMx8ROllo4vyTmwLscjAlGGP6k0X2YKgXSxIuVljVKQtOi4vlLHuxOy9fu0mfAxOx3cTUguJYY= X-Received: by 2002:a25:828e:0:b0:d9a:da03:2417 with SMTP id r14-20020a25828e000000b00d9ada032417mr14849509ybk.45.1701185268068; Tue, 28 Nov 2023 07:27:48 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 28 Nov 2023 07:27:36 -0800 Message-ID: Subject: Re: [FlyRotary] Re: RD-C input shaft failure To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000099b5e7060b380f4e" --00000000000099b5e7060b380f4e Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable good question, I'm not sure how they do it in the truck. yes, I do have Tracy's original dampers still installed. Dave Leonard On Tue, Nov 28, 2023, 2:10 AM Stephen Izett stephen.izett@gmail.com < flyrotary@lancaironline.net> wrote: > I=E2=80=99m wondering how the Sun gear was attached to the shaft in the o= rignal > Ford transmission? > > Steve > > > On 28 Nov 2023, at 6:01=E2=80=AFpm, Stephen Izett wrote: > > Thanks Dave > > My question about the damper was me wondering if damping the engine torqu= e > pulses reduced the stress on the pin/s > > Steve > > On 28 Nov 2023, at 5:11=E2=80=AFpm, David Leonard wdleonard@gmail.com < > flyrotary@lancaironline.net> wrote: > > There is really no such thing as an AD for these non certified parts. > Yes, my redrive is the RD-1B with the 2.17:1 ratio. The part that fails > here is the connection of the sun gear to the input shaft. The input shaf= t > fits inside the sun gear and they are fixed in place with either a weld o= r > a pin or two. The pin is about 3/8 in diameter. > > I believe the RC-1C uses the same input shaft and sun gear, but I am not > sure. > > This is a different issue from the flywheel. The original design called > for the use of the auto transmission flex plate to transmit the torque > loads from the engine output shaft to the plate with the dampeners. > However, in the car this was only used for starting, and not to transmit > the whole power of the engine. Over time they tend to flex and crack. > There are a couple of different solutions including replacing the flex > plate with a flywheel like I did. > > The 3rd failure mode that I came across was my failure to supply a > dedicated oil line from a high pressure area which caused the plain > bearings to seize. However, that was at Reno with high power and high > gyroscopic loads. > > Dave Leonard > > On Mon, Nov 27, 2023 at 10:33=E2=80=AFPM Stephen Izett stephen.izett@gmai= l.com < > flyrotary@lancaironline.net> wrote: > >> Hi Guys. >> >> Has an AD been issued on the RD1-C PSRU? >> How many of these failures has there been? >> >> Now I=E2=80=99m thinking I understood yours Dave was an earlier version = with a >> lower ratio but the shaft assembly may be exactly the same. >> Do you both have the damper with original shore hardness donuts? I recal= l >> Dave changing to a modified low weight steel or ali flywheel. >> >> You have my attention! >> >> Steve Izett >> Genesis 4 Port RD1-C MTV-7C >> >> >> On 28 Nov 2023, at 12:07=E2=80=AFpm, David Leonard wdleonard@gmail.com < >> flyrotary@lancaironline.net> wrote: >> >> Hi Dennis, >> This happened to me 3 times, Once with the older style weld, and then >> twice with the pin. After the pin sheared for the second time I sent it >> back to Tracy and he placed a second pin 90 deg to the first one. That = fix >> has held up for a couple hundred hours including racing at Reno (appx >> 300h.p.). >> >> Of note, 2 of the failures occurred during long gradual descents at low >> power. The other occurred after a backfire during start-up. I have a >> suspicion that low power descents cause the prop and engine to >> alternately overrun each other causing a rapid hammering back and forth. >> This problem is made worse by the somewhat lax gear leash that Tracy >> designed into the PSRU. I believe that was a good choice for normal >> operation but may make things worse during periods when the plane is >> pushing the prop yet enough power is being produced to cause the torque = to >> alternate directions. >> >> So in addition to the 2 pins, I now make sure that I keep adequate power >> applied throughout descents so that the torque remains positive. In ste= ep >> descents idle power will probably allow the torque to remain negative wh= ich >> is also OK. >> >> Hope you are doing well, glad to hear that you are still flying. A >> machine shop should be able to place a new pin and machine a hole for a >> second pin. >> >> Cheers. >> David Leonard >> Turbo Rotary RV-6, N4VY >> >> On Mon, Nov 27, 2023 at 7:09=E2=80=AFPM Dennis Haverlah clouduster@austi= n.rr.com >> wrote: >> >>> The shaft between the RX-8 engine and the reduction drive unit has a >>> gear secured to the shaft with a steel pin. (The gear drives the plane= tary >>> gear set). The steel pin sheared off allowing the gear to rotate on the >>> shaft. I understand this has happened to others in the past. I=E2= =80=99ve heard >>> that several fixes were proposed or tried =E2=80=93 welding the pin to = the gear, >>> doing more deforming of the pin at the gear surface or installing a >>> tighter or larger pin. I have another new shaft/gear assembly I plan = to >>> install after I incorporate *improvements.* >>> >>> When the pin sheared the gear only rotated about 3/32 inch on the shaft= . >>> The two pieces of the pin outside the shaft were thrown out of the gear= and >>> apparently were chewed into very small particles by the planetary gear >>> assembly. >>> >>> >>> Any info. You may have will be highly appreciated! >>> >>> I have about 920 hours on my RX-8 engine in my RV-7A >>> >>> >>> >>> Dennis Haverlah >>> >>> 512-921-0636 >>> >>> >>> >>> Sent from Mail for >>> Windows >>> >>> >>> >>> >>> >> >> > > --00000000000099b5e7060b380f4e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
good question, I'm not sure how they do it in the tru= ck. yes, I do have Tracy's original dampers still installed.

Dave Leonard=C2=A0

On Tue, Nov 28, = 2023, 2:10 AM Stephen Izett step= hen.izett@gmail.com <= flyrotary@lancaironline.net> wrote:
I=E2=80=99m wondering h= ow the Sun gear was attached to the shaft in the orignal Ford transmission?=

Steve


On 28 Nov 202= 3, at 6:01=E2=80=AFpm, Stephen Izett <stephen.izett@gmail.com&g= t; wrote:

Thanks = Dave

My question about the damper was me wondering if da= mping the engine torque pulses reduced the stress on the pin/s
Steve

On 28 Nov 2023, at 5:11=E2=80= =AFpm, David Leonard wdleonard@gmail.com <flyrotary@lancai= ronline.net> wrote:

There is really n= o such thing as an AD for these non certified parts.=C2=A0 Yes, my redrive = is the RD-1B with the 2.17:1 ratio.=C2=A0 The part that fails here is the c= onnection of the sun gear to the input shaft. The input shaft fits inside t= he sun gear and they are fixed in place with either a weld or a pin or two.= =C2=A0 The pin is about 3/8 in diameter.=C2=A0=C2=A0

I b= elieve the=C2=A0RC-1C uses the same input shaft and sun gear, but I am not = sure.

This is a different issue from the flywheel.= =C2=A0 The original=C2=A0design called for the use of the auto transmission= flex plate to transmit the torque loads from the engine=C2=A0output shaft = to the plate with the dampeners.=C2=A0 However, in the car this was only us= ed for starting, and not to transmit the whole power of the engine.=C2=A0 O= ver time they tend to flex and crack.=C2=A0 There are a couple of different= solutions including replacing the flex plate with a flywheel like I did.

The 3rd failure mode that I came across was my fail= ure to supply a dedicated=C2=A0oil line from a high pressure area which cau= sed the plain bearings to seize.=C2=A0 However, that was at Reno with high = power and high gyroscopic loads.

Dave Leonard

On Mon, Nov 27, 2023 at 10:33=E2=80=AFPM Stephen Izett stephen.izett@= gmail.com <flyrotary@lancaironline.net> wrote:
Hi Guys.
Has an AD been issued on the RD1-C PSRU?
How many of = these failures has there been?

Now I=E2=80=99m thi= nking I understood yours Dave was an earlier version with a lower ratio but= the shaft assembly may be exactly the same.
Do you both have the= damper with original shore hardness donuts? I recall Dave changing to a mo= dified low weight steel or ali flywheel.

You have = my attention!

Steve Izett
Genesis 4 Port= RD1-C MTV-7C


O= n 28 Nov 2023, at 12:07=E2=80=AFpm, David Leonard wdleonard@gmail.com = <flyrotary@lancaironline.net> wrote:

Hi Dennis,
This happened to me 3 times, Once with the older= style weld, and then twice=C2=A0with=C2=A0the pin.=C2=A0 After the pin she= ared for the second time I sent it back to Tracy and he placed a second pin= 90 deg to the first one.=C2=A0 That fix has held up for a couple hundred h= ours including racing at Reno (appx 300h.p.).

Of n= ote, 2 of the failures occurred=C2=A0during=C2=A0long gradual descents at l= ow power.=C2=A0 The other occurred=C2=A0after a backfire during start-up.= =C2=A0 I have a suspicion=C2=A0that low power descents cause the prop and e= ngine to alternately=C2=A0overrun=C2=A0each other causing a rapid hammering= back and forth.=C2=A0 This problem is made worse by the somewhat lax gear = leash that Tracy designed into the PSRU.=C2=A0 I believe that was a good ch= oice for normal operation but may make things worse during periods when the= plane is pushing the prop yet enough power is being produced to cause the = torque to alternate directions.

So in addition to = the 2 pins, I now make sure that I keep adequate power applied throughout d= escents so that the torque remains positive.=C2=A0 In steep descents idle p= ower will probably allow the torque to remain negative which is also OK.

Hope you are doing well, glad to hear that you are s= till flying. A machine shop should be able to place a new pin and machine a= hole for a second pin.

Cheers.
David Le= onard
Turbo Rotary RV-6,=C2=A0 N4VY

On Mon, Nov 27, 2023 at = 7:09=E2=80=AFPM Dennis Haverlah clouduster@austin.rr.com <flyrotary@lancaironline.net> wrote:

The shaft between the RX-8 engine and the reduction drive unit h= as a gear secured to the shaft with a steel pin. =C2=A0(The gear drives the= planetary gear set). The steel pin sheared off allowing the gear to rotate= on the=C2=A0 shaft.=C2=A0=C2=A0 I understand this has happened to others i= n the past.=C2=A0=C2=A0 I=E2=80=99ve heard that several fixes were proposed= or tried =E2=80=93 welding the pin to the gear, doing more deforming of = =C2=A0the pin at the gear surface or installing a tighter or larger pin.=C2= =A0 =C2=A0I have another new shaft/gear assembly I plan to install=C2=A0 af= ter I incorporate =C2=A0improvements.=C2=A0

When the pin sheared the gear only rotated about 3/32 inch on the shaft.= The two pieces of the pin outside the shaft were thrown out of the gear an= d apparently were chewed into very small particles by the =C2=A0planetary g= ear assembly.=C2=A0

=C2=A0

Any inf= o. You may have will be highly appreciated!

I have about 920 hours on my RX-8 engine in my RV-7A

=C2=A0

Dennis Haverl= ah

512-921-0636

=C2=A0

Sent from M= ail for Windows

=C2=A0

=C2=A0




--00000000000099b5e7060b380f4e--