X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from mail-yw1-f182.google.com ([209.85.128.182] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 2658785 for flyrotary@lancaironline.net; Wed, 29 Nov 2023 15:15:40 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.128.182; envelope-from=wdleonard@gmail.com Received: by mail-yw1-f182.google.com with SMTP id 00721157ae682-5cd59f77d2dso1478307b3.3 for ; Wed, 29 Nov 2023 12:15:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701288924; x=1701893724; 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=FtuN4pL6mZgMnnpaUVwWZOf0t8oWCvKOL3y21V2DCPY=; b=Qgpo9ttfp3zje3AMxUGbtECVXrgdYFx4/qeuHDNBfuAP+Ox78LH9CVOICjHW1QJbig J2a5P+0ZLHzOnCZD0hsphznCOSiLgd7wZuj5kDeIK9zRZcGj2D7Mc9YLtnFPfPrsffNg PD8gN6DYi7wuwRn5o8krrZD5IsmuA1LTaWQNpd6qq9VJczhD/b4+Om3drKRnXk/AkqCT 7qVsOwsxrcDbDMmLzWCoBu7/V1WDlTVAuwY5I3vUoB7m0aY8fXohxCYUsAC2L9hpQgkT 4Ho5C4EUmfKF1LVw3T2E/k1rqFHthvF7sJ5l8xJuq1kOj3sBc5QcNvHtAlyyEfa2V7qk rvAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701288924; x=1701893724; 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=FtuN4pL6mZgMnnpaUVwWZOf0t8oWCvKOL3y21V2DCPY=; b=Sy0Va3uENrcwZJNOjIctG9s4iYSIaPXomlsgnx8r9g02R6T1gBjPYhqGWqTCnA+bIi EHtHlmLy78oQnvVvOjb/UmETHxvhtQGVtQB8OGZ3lXdauoYlGsf00YiWiRwNQfmcZ9mc EVgQWmvu1AsiTP2kPv5z5uoSNBmv2jLIjr1WgxZIVQvgvlxvioNQ2WkoKAiQ1STcEdmF 2ezauo+jryfjyqFm6kUpKntYfv2ZsHmLn52F/+9Mt5qsAUKUgkNRudl3Z052uSj7mASl Vefwlwdb7by56abjTCzQtpVg5MT2Ep0XqtDhZz1JmkU/hkmCzdP2pUPxwLwByWTzZZdg 7nYA== X-Gm-Message-State: AOJu0YwUcFdxV7rmb3sAdEogOZ/S011po6/ZrH00Bk0rzWqE3i3Ffz4j PQzGFUqiviL07q/V7rRyVN8pmp2qO/sDrIqvJOtwV6gC7KY= X-Google-Smtp-Source: AGHT+IH1Of9GM092ZkQokr+OjVY5g/OjaDWixPqX6ArtiGvo0e7rrG8opohli1Lfew353s7o6kcabR+3vw7+lmZCFQY= X-Received: by 2002:a0d:ee41:0:b0:57a:cf8:5b4 with SMTP id x62-20020a0dee41000000b0057a0cf805b4mr18769646ywe.51.1701288923935; Wed, 29 Nov 2023 12:15:23 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Wed, 29 Nov 2023 12:15:12 -0800 Message-ID: Subject: Re: [FlyRotary] Re: RD-C input shaft failure To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="000000000000f8b83b060b50315b" --000000000000f8b83b060b50315b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I cannot recall exactly, Tracy seemed convinced that the engineering was sufficient, which I is another reason that I believe is was a problem with vibration at low power during descents. I vaguely recall that maybe at some point he started using bigger pins, but thats all I got. Dave Leonard On Wed, Nov 29, 2023 at 7:24=E2=80=AFAM Marc Wiese cardmarc@charter.net < flyrotary@lancaironline.net> wrote: > Did Tracy ever publish a fix for this failure mode, and did ALL his model= s > have this weakness? IOW, was there ever a -D model or when did the C begi= n > the mods to overcome this weakness? > > M > > > > > > 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 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 > > > > > > > > > > > > > > > Virus-free.www.avast.com > > > > --000000000000f8b83b060b50315b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I cannot recall exactly,=C2=A0 Tracy seemed convinced that= the engineering was sufficient, which I is another reason that I believe i= s was a problem with vibration at low power during descents.=C2=A0 I vaguel= y recall that maybe at some point he started=C2=A0using bigger pins, but th= ats all I got.

Dave Leonard

On Wed, Nov 29, 2023 at= 7:24=E2=80=AFAM Marc Wiese cardmar= c@charter.net <flyrot= ary@lancaironline.net> wrote:

Did Tracy ever publish a fix for this failure mode, and did = ALL his models have this weakness? IOW, was there ever a -D model or when d= id the C begin the mods to overcome this weakness?

=

= M

=C2=A0



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

= =C2=A0

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.).

<= div>

=C2=A0

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 duri= ng start-up.=C2=A0 I have a suspicion=C2=A0that low power descents cause th= e prop and engine to alternately=C2=A0overrun=C2=A0each other causing a rap= id hammering back and forth.=C2=A0 This problem is made worse by the somewh= at lax gear leash that Tracy designed into the PSRU.=C2=A0 I believe that w= as a good choice for normal operation but may make things worse during peri= ods when the plane is pushing the prop yet enough power is being produced t= o cause the torque to alternate directions.

=C2=A0

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.=C2=A0 In = steep descents idle power will probably allow the torque to remain negative= which is also OK.

=C2=A0

Hope you are doing wel= l, 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.

=C2=A0

Cheers.

D= avid Leonard

Turbo Rotar= y RV-6,=C2=A0 N4VY

<= /u>=C2=A0

On Mon, Nov 27, 2023 a= t 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 dr= ive unit has 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 t= o others in the past.=C2=A0=C2=A0 I=E2=80=99ve heard that several fixes wer= e proposed or tried =E2=80=93 welding the pin to the gear, doing more defor= ming 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 after I incorporate =C2=A0improvements.=C2=A0 <= /p>

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 th= rown out of the gear and apparently were chewed into very small particles b= y the =C2=A0planetary gear 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

D= ennis Haverlah

512-921-0636=

=C2=A0

Sent from Mail for Windows

=C2=A0

=C2=A0

=C2=A0

=C2=A0

=C2=A0

=

Virus-free.www.avast.co= m

=C2=A0

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