X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Stephen Izett stephen.izett@gmail.com" Received: from mail-il1-f170.google.com ([209.85.166.170] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 2652604 for flyrotary@lancaironline.net; Tue, 28 Nov 2023 01:33:35 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.166.170; envelope-from=stephen.izett@gmail.com Received: by mail-il1-f170.google.com with SMTP id e9e14a558f8ab-35cd435e8f6so6263135ab.3 for ; Mon, 27 Nov 2023 22:33:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701153199; x=1701757999; darn=lancaironline.net; h=message-id:in-reply-to:to:references:date:subject:mime-version:from :from:to:cc:subject:date:message-id:reply-to; bh=tpMzHIyQBDQZWWrAIMEYxRbbBEE8asIMgfGDCJc2qxo=; b=eFpKFxdU0s7AoJaWfVyeDSjqLHG2VU86f7QSeuaWMHVHtSQOVfm63QuzkUQkLG7N+5 TC6NVQ3aTVaejI3GrT93jnulF2FpLF4FXDRteh5L0odTAJj+qG/MPFdCB5R/mklHywH5 h4MgubhgeEjpFjkY+xxvyFLpal7uXNTuvfzqeAtPMYJGJbna/TdqoiIAaQBdSQF3EW1b c8JuF+Byru528MMq5QpZazhor5PeEr+8wXXhQKjd4KFRUGgfH1rxj09J7aIwoA5ZCmyz 0axfVDlLOslQc6FS3LquYabAyL03Gv/z2IPHH+/sbgTDlACDotQuyoc6j9XhTsesAds0 j4Cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701153199; x=1701757999; h=message-id:in-reply-to:to:references:date:subject:mime-version:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tpMzHIyQBDQZWWrAIMEYxRbbBEE8asIMgfGDCJc2qxo=; b=pRJGyQMsFZnT8wXg1Sc4BnCZCcdJKPtvNKJFwdiy0UeZxWJSQWMoF7mVO6vI2lX9ne B7l+mp0zWQsICrjHWaOisxpGEubSGAbT0yGdKc3vkR1UZ+lNzOw16j5AYyj0rAbmm/zr pONnflOq6OX/0rqFj9ffLhJhDruKy6K0X2hh9bCzKlnwYMaMnnnfbOmM8mv0kYUlHcTo y3sClSiZmp25Q8/M0t7kE9vwvhEwUDuosKiUFRolF1YFkxJWTH4PEtA7j2c9nERRaEkM u1rBCpCc8+7n5KH9Q/DAgFzhtbqUbTMP9FE0HGDtFyEBFghnL1SlgSyKxynzmk0SZaWk imSQ== X-Gm-Message-State: AOJu0Yx6WJEPctXxfjZFzGwoXTh/74pXXxSM9FLGx5A4z4JLBsl5lD8d Ank9ai/+s9KWc6ZaVyqhjmNPeqlB4yo= X-Google-Smtp-Source: AGHT+IFwa1H2Gr8xXVc0J1/vZ1R1uo/cA3ex52zGUQW4dF4+DXPemWPh8PJDdBiVgN/TwnuSd9WmmA== X-Received: by 2002:a92:cd43:0:b0:35c:b3ba:857e with SMTP id v3-20020a92cd43000000b0035cb3ba857emr9373625ilq.25.1701153198598; Mon, 27 Nov 2023 22:33:18 -0800 (PST) Return-Path: Received: from smtpclient.apple (203-59-74-185.perm.iinet.net.au. [203.59.74.185]) by smtp.gmail.com with ESMTPSA id q28-20020a056a0002bc00b006cb9a9ea64dsm8254570pfs.220.2023.11.27.22.33.17 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Nov 2023 22:33:18 -0800 (PST) Content-Type: multipart/alternative; boundary="Apple-Mail=_5C4CE7AF-FE12-488F-9A46-BF373879A9B5" Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.200.91.1.1\)) Subject: Re: [FlyRotary] RD-C input shaft failure Date: Tue, 28 Nov 2023 14:33:04 +0800 References: To: Rotary motors in aircraft In-Reply-To: Message-Id: <85E00320-D684-4936-AC92-5EBF4A6F282D@gmail.com> X-Mailer: Apple Mail (2.3774.200.91.1.1) --Apple-Mail=_5C4CE7AF-FE12-488F-9A46-BF373879A9B5 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 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 = 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 = wrote: >=20 > 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.). >=20 > 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. >=20 > 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. >=20 > 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. >=20 > Cheers. > David Leonard > Turbo Rotary RV-6, N4VY >=20 > On Mon, Nov 27, 2023 at 7:09=E2=80=AFPM Dennis Haverlah = clouduster@austin.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 = planetary 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.=20 >>=20 >> 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.=20 >>=20 >> =20 >> Any info. You may have will be highly appreciated! >>=20 >> I have about 920 hours on my RX-8 engine in my RV-7A >>=20 >> =20 >>=20 >> Dennis Haverlah >>=20 >> 512-921-0636 >>=20 >> =20 >>=20 >> Sent from Mail for = Windows >>=20 >> =20 >>=20 >> =20 >>=20 --Apple-Mail=_5C4CE7AF-FE12-488F-9A46-BF373879A9B5 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 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 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 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.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 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

 

 


= --Apple-Mail=_5C4CE7AF-FE12-488F-9A46-BF373879A9B5--