X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from mail-yw1-f173.google.com ([209.85.128.173] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 2652750 for flyrotary@lancaironline.net; Tue, 28 Nov 2023 04:11:42 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.128.173; envelope-from=wdleonard@gmail.com Received: by mail-yw1-f173.google.com with SMTP id 00721157ae682-5cc77e23218so52961507b3.3 for ; Tue, 28 Nov 2023 01:11:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701162687; x=1701767487; 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=djD+iLs6soN4TpKrpn+4XRAAAT1lyqBBcQBcOt4TBeo=; b=Z1uaUcMkghsVj9gmVfdJC76PAtSjXPpeffRnDwkheHSfLykq2/7LQ/xv+xh8S+zQg+ 5FixQdzxEiOG6a5LeMnQwFq2AuXkfdE9GYPvLxzdFYqYgYP8y/MfZv4Yhi8bksJijzkX SexaRnVfCg/LtP9JlZr//qFF+dyi1p8dJtUVtItGbsse6sKcI1c8hw3/+mTx8lbjz//l PgjFDyu6kaOfHUZho3FpiCkmuwlTKLMgw9Ai7qYDUnOlX2xEU002Awr/upQmZJAZVAMO WJkfGaHhdj61VNzpqAwyAh5FBsvp82XBjdT5ZTTvVoR9hzfwnvFJO7Nf6+PKXjIVSK0+ oncw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701162687; x=1701767487; 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=djD+iLs6soN4TpKrpn+4XRAAAT1lyqBBcQBcOt4TBeo=; b=TU/+j8k/Ga0SkBB9K8ZtsG91QRgvkD1LNDoUhevgtTiMytWu2xbImeC3wX/U1ILgP+ smcDmvdp67V6skCXUZbHGt3uodrt+ve8cKzU9jcpIjAJT0HSlGDC64WXMZotAJ5/HQbv iaxyt67wHg9OT8EoWLGFC9VplM7vIjwER/xogsVX3Fi5yEU+93Drnw7rrUCi9VOEnMep 1cyPPiGSlEzoPF64EkDMwuZHdCGFDSopVWtbqWfMjzyO5JN6pvds2yOgltWQKUaNUIBf 6zJG7gKqE8sY4ICVa0UiTUZl/iwqyB27+GQuKuxuW4ViZdvMtANY/2LwPyD6YWRWWVC2 1XPw== X-Gm-Message-State: AOJu0Yw7vrRQKcjB5ge5TkcA/gkFIMcTKA6AlEn1VE7jqeUda8HjhGpi s7LhB2tm11pkRp3A03N4aPdeZ9LVyCWZQ1f5JU/5dW43h78= X-Google-Smtp-Source: AGHT+IHiJX0JODAAoodQ5eY+q7uNqWDZL2dqAujHnMXm9s5Wxy8OsPp11CdiNYMEIl93RYN9hEG82c8l1S/QP3hHxr0= X-Received: by 2002:a81:65c2:0:b0:5cc:3af6:290 with SMTP id z185-20020a8165c2000000b005cc3af60290mr14865838ywb.39.1701162687207; Tue, 28 Nov 2023 01:11:27 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 28 Nov 2023 01:11:15 -0800 Message-ID: Subject: Re: [FlyRotary] Re: RD-C input shaft failure To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="000000000000ad1ca3060b32cd17" --000000000000ad1ca3060b32cd17 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 shaft fits inside the sun gear and they are fixed in place with either a weld or 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@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 thinking I understood yours Dave was an earlier version w= ith 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 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 f= ix > 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 t= o > 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 stee= p > descents idle power will probably allow the torque to remain negative whi= ch > is also OK. > > Hope you are doing well, glad to hear that you are still flying. A machin= e > shop should be able to place a new pin and machine a hole for a second pi= n. > > Cheers. > David Leonard > Turbo Rotary RV-6, 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 has a gea= r >> secured to the shaft with a steel pin. (The gear drives the planetary g= ear >> 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 t= he 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 t= o >> 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 >> >> >> >> >> > > --000000000000ad1ca3060b32cd17 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
There is really no such thing as an AD for these non certi= fied 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 connection of the sun gear to the input sh= aft. The input shaft fits inside the sun gear and they are fixed in place w= ith either a weld or a pin or two.=C2=A0 The pin is about 3/8 in diameter.= =C2=A0=C2=A0

I believe the=C2=A0RC-1C uses the same inpu= t shaft and sun gear, but I am not sure.

This is a= different issue from the flywheel.=C2=A0 The original=C2=A0design called f= or 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 H= owever, in the car this was only used for starting, and not to transmit the= whole power of the engine.=C2=A0 Over 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 failure to supply a dedicated=C2=A0oil line = from a high pressure area which caused the plain bearings to seize.=C2=A0 H= owever, that was at Reno with high power and high gyroscopic loads.

Dave Leonard

On Mon, Nov 27, 2023 at 10:33=E2=80=AFP= M Stephen Izett stephen.izett@gm= ail.com <flyrotary@la= ncaironline.net> wrote:
Hi Guys.

Has an AD been issued on th= e RD1-C PSRU?
How many of these failures has there been?

Now I=E2=80=99m thinking I understood yours Dave was an ea= rlier version with a lower ratio but the shaft assembly may be exactly the = same.
Do you both have the damper with original shore hardness do= nuts? I recall 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 &= lt;flyrota= ry@lancaironline.net> wrote:

Hi Denni= s,
This happened to me 3 times, Once with the older style weld, and the= n twice=C2=A0with=C2=A0the pin.=C2=A0 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.=C2=A0 That fix has held up for a couple hundred hours including racin= g at Reno (appx 300h.p.).

Of note, 2 of the failur= es occurred=C2=A0during=C2=A0long gradual descents at low power.=C2=A0 The = other occurred=C2=A0after a backfire during start-up.=C2=A0 I have a suspic= ion=C2=A0that low power descents cause the prop and engine 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 de= signed into the PSRU.=C2=A0 I believe that was a good choice for normal ope= ration but may make things worse during periods when the plane is pushing t= he prop yet enough power is being produced to cause the torque to alternate= directions.

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

<= div>Hope you are doing well, glad to hear that you are still flying. A mach= ine shop should be able to place a new pin and machine a hole for a second = pin.

Cheers.
David Leonard
Tur= bo Rotary RV-6,=C2=A0 N4VY

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

The shaft between the RX-8 engine and the reduc= tion drive unit has a gear secured to the shaft with a steel pin. =C2=A0(Th= e gear drives the planetary gear set). The steel pin sheared off allowing t= he gear to rotate on the=C2=A0 shaft.=C2=A0=C2=A0 I understand this has hap= pened to others in the past.=C2=A0=C2=A0 I=E2=80=99ve heard that several fi= xes were proposed or tried =E2=80=93 welding the pin to the gear, doing mor= e 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 i= nstall=C2=A0 after I incorporate =C2=A0improvements.=C2=A0

When the pin sheared the gear only rotated about 3/32 inc= h 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 = =C2=A0planetary gear assembly.=C2=A0

=C2=A0

Any info. You may have will be highly appreciated!<= /p>

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

=C2=A0

Dennis Haverlah

512-921-0636

=C2=A0

Sent from Mai= l for Windows

=C2=A0

=C2=A0


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