X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from mail-yw1-f174.google.com ([209.85.128.174] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 2652497 for flyrotary@lancaironline.net; Mon, 27 Nov 2023 23:08:12 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.128.174; envelope-from=wdleonard@gmail.com Received: by mail-yw1-f174.google.com with SMTP id 00721157ae682-5cc589c0b90so50143417b3.2 for ; Mon, 27 Nov 2023 20:08:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701144476; x=1701749276; 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=dF6+kCgCS5n5Zh3gEE6qTvFOmMtGlu61gu8elBlz1EM=; b=nbYCv4275IYA0mrT+KHC4M5K7LnU4RrUmB5BoU1bu/SZygVe2CbgMfrEvI1MlsO6sL hJKccfktIdr/6Ru31lC8biEAkyqVj674S7wCqnN7lAWF+/f/Hn58dWlGJUgGeEmtN4+W DCJ6UQHZbg5z4kYh/LTRg+JxSNQFZTqPGfX7rSmcNafx5uwgArwarsaQeqiXUTUsr+2Q 4wXD/3umA2Q48UEJhmDkSKL/1JP82D/ELy7UV5Pt6LM5ki99qj2nxr//SZ/jLGch7SfB fpQhP4TBlEi7roEkdQQrRrtksscz/gp1gYyAwjWeFr7GQ0xr12I9ugHDd3l8eqWriuYj 0IRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701144476; x=1701749276; 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=dF6+kCgCS5n5Zh3gEE6qTvFOmMtGlu61gu8elBlz1EM=; b=mvHVUUphEcGOIwV/okTIJ0NYjo1T/e/oihlyYr1q7PHl2qQg1xA3fFgAlePktnFnG3 PIFF2+1/zPzcmlt4O2+LZq68OSU7OwZYe87V/4r4ddnCghzhj+N0oZ4tt0BpVRgSbvMV WHeshZli/ofmywFYYErWQKNIwm2asgYSK7BCC4IbO7Om6tflDHsHu/odMaBMnUVVWCE+ nL6bQQ3ew0bYxVlx+jFgvzymsQddaONmmAYrLAdqchimizZQ+NJc8RPq/L+SpmVeaTo2 wZ5enfGjbZ5LS4dRKpJFyoKrTJButq77qFSkbUqdEsvO+822ej6O3Aw9rkjgTD9Rpbfn 3q5w== X-Gm-Message-State: AOJu0YyDRn6G58mh23w6amVmIil/ECyDZs0HBGRX99qPipVoHzdnUx1t MHZL93gSYbVz2KDC0WohejZhqfESAQMgi0F/G7ReLLW4sv8= X-Google-Smtp-Source: AGHT+IGOIRHmJm2iIHhKiEUX6b9HxdQmYGl0Wp1lvq83PA3g41FNrslM5qVnQqF+ac9gd2vYRHOcSLPVHxiV9ctvR1s= X-Received: by 2002:a05:690c:886:b0:5cf:2d42:a61a with SMTP id cd6-20020a05690c088600b005cf2d42a61amr9697099ywb.29.1701144475900; Mon, 27 Nov 2023 20:07:55 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Mon, 27 Nov 2023 20:07:43 -0800 Message-ID: Subject: Re: [FlyRotary] Re: RD-C input shaft failure To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000032a179060b2e9033" --00000000000032a179060b2e9033 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 steep descents idle power will probably allow the torque to remain negative which 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@austin.r= r.com < flyrotary@lancaironline.net> 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 planetary ge= ar > 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 th= e 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 a= nd > 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 > > > > > --00000000000032a179060b2e9033 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
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 pi= n sheared for the second time I sent it back to Tracy and he placed a secon= d pin 90 deg to the first one.=C2=A0 That fix has held up for a couple hund= red hours including racing at Reno (appx 300h.p.).

Of note, 2 of the failures 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 suspicion=C2=A0that low power descents cause the prop an= d engine to alternately=C2=A0overrun=C2=A0each other causing a rapid hammer= ing back and forth.=C2=A0 This problem is made worse by the somewhat lax ge= ar leash that Tracy designed into the PSRU.=C2=A0 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 t= he torque to alternate directions.

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

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

Cheers.
David= Leonard
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 t= he RX-8 engine and the reduction drive unit has a gear secured to the shaft= with a steel pin. =C2=A0(The gear drives the planetary gear set). The stee= l pin sheared off allowing the gear to rotate on the=C2=A0 shaft.=C2=A0=C2= =A0 I understand this has happened to others in 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 surf= ace or installing a tighter or larger pin.=C2=A0 =C2=A0I have another new s= haft/gear assembly I plan to install=C2=A0 after I incorporate =C2=A0imp= rovements.=C2=A0

When the pin sheared the ge= ar only rotated about 3/32 inch on the shaft. The two pieces of the pin out= side 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 wi= ll be highly appreciated!

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

=C2=A0

Dennis Haverlah

512-921-0636

=C2=A0

Sent from Mail for Windows

=C2=A0

=C2=A0<= /p>

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