Return-Path: Received: from mail11.syd.optusnet.com.au ([211.29.132.192] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP-TLS id 724366 for flyrotary@lancaironline.net; Thu, 10 Feb 2005 17:55:11 -0500 Received-SPF: none receiver=logan.com; client-ip=211.29.132.192; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-119-41.dsl.nsw.optusnet.com.au [211.31.119.41]) by mail11.syd.optusnet.com.au (8.12.11/8.12.11) with SMTP id j1AMsNZn022276 for ; Fri, 11 Feb 2005 09:54:24 +1100 Message-ID: <006e01c50fc3$c4b19960$29771fd3@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: PSRU - hub/prop end Date: Fri, 11 Feb 2005 08:56:33 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_006B_01C51017.96146B60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_006B_01C51017.96146B60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tracy, I guess that was directed at me, and that's a Yes! I had requested that info from the Chief Engineer at Timken Australia, = who provide those figures. If memory serves me I quoted 3,000 RPM. Butch suggested that 250,000 hrs was way overkill ! That's not to say they are the best bearing for the job, but they are a = very robust bearing - that's for sure. The big problem for any bearing is cooling, so a TRB with much larger = surface area than ( for instance) a plain ball bearing, requires more = cooling. I had originally wanted to use TRB on my own Aussie design, as an = engineer mate explained - their so robust, but have been since coerced = by Butch to consider other options.=20 George ( down under) One question, did you plug in the RPM used in this application when = calculating bearing life? It goes down real fast on some bearings = (especially tapered rollers). Tracy ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 09, 2005 5:30 PM Subject: [FlyRotary] Re: PSRU - hub/prop end Ernest, Seems like you have it completely under control, if you researched = the life of the bearings, under the loads they carry you will find that their projected life would be something like 250,000 hours. That's the answer I got from Timken! but the sizes may have been = different. Anyway it gives you a bit of an idea. George ( down under) > Did some research last night, and I am now very comfortable with = the > taper bearing. There is in fact one on the other end, but I was = not > considering it, because I view all the forces trying to pull the = hub off > the shaft and the rear bearing won't see much stress in that = situation. > Now I realize that the rear bearing will be important to keep the = hub > aligned properly, and this won't happen unless the correct preload = is > applied. I also understand that the correct term for the load = forces > are axial and radial, not longitudanal and lateral. > > >The nut will be for preload, remember when you put it back on, = that you know > >the preload number. > > > > > > > > Unfortunately, the nut was finger tight and the keyed lock washer = had > never been bent to lock it in place. I have no idea what the = preload > number is or how to determine it. On cars, we always just = tightened the > nut till there was no side play in the wheel but it still spun = freely. > I would think that I'd want it a little tighter in this = application, > since the forces will be trying to open up the rear seal and the = only > thing stopping that will be the preload...but I don't have a = number to > attach to 'little tighter'. > > >Again go to a bearing supply company, I have no doubt that there = would be a > >standard seal to fit. Who ever made this PSRU would look for = standard seal > >sizes. > > > >George ( down under) > > > > > > Thank you, George. I looked over Tracey's website (thank you, = Tracey), > and several other places. I think in the application that this = hub was > meant for (a racecar wheel), that the car's wheel was the seal. I = have > a 1/4" plate that will sandwich nicely between the prop and the = hub. I > can easily machine a recess into it for a standard seal (I think). > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html > >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_006B_01C51017.96146B60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tracy,
I guess that was directed at me, and that's a=20 Yes!
I had requested that info from the=20 Chief Engineer at Timken Australia, who provide those figures. = If=20 memory serves me I quoted 3,000 RPM.
 
Butch suggested that 250,000 hrs was way = overkill=20 !
That's not to say they are the best bearing for = the job,=20 but they are a very robust bearing - that's for sure.
 
The big problem for any bearing is cooling, = so a TRB=20 with much larger surface area than ( = for=20 instance) a plain ball bearing, requires more cooling.
 
I had originally wanted to use TRB on my own = Aussie=20 design, as an engineer mate explained - their so robust, but have been since coerced by Butch to consider other = options. 
George ( down under)
One question,  did you plug in the RPM used in this = application when=20 calculating bearing life?  It goes down real fast on some = bearings=20 (especially tapered rollers).
 
Tracy
----- Original Message -----
From: George Lendich
To: Rotary motors in = aircraft=20
Sent: Wednesday, February 09, = 2005 5:30=20 PM
Subject: [FlyRotary] Re: PSRU = -=20 hub/prop end

Ernest,
Seems like you have it completely under = control,=20 if you researched the life
of the bearings, under the loads they = carry=20 you will find that their
projected life would be something like = 250,000=20 hours.
That's the answer I got from Timken! but the sizes may = have been=20 different.
Anyway it gives you a bit of an idea.
George ( down = under)

> Did some research last night, and I am now very=20 comfortable with the
> taper bearing.  There is in fact = one on=20 the other end, but I was not
> considering it, because I view = all the=20 forces trying to pull the hub off
> the shaft and the rear = bearing=20 won't see much stress in that situation.
> Now I realize that = the rear=20 bearing will be important to keep the hub
> aligned properly, = and this=20 won't happen unless the correct preload is
> applied.  I = also=20 understand that the correct term for the load forces
> are = axial and=20 radial, not longitudanal and lateral.
>
> >The nut = will be=20 for preload, remember when you put it back on, that = you
know
>=20 >the preload number.
> >
> >
>=20 >
>
> Unfortunately, the nut was finger tight and the = keyed=20 lock washer had
> never been bent to lock it in place.  I = have no=20 idea what the preload
> number is or how to determine = it.  On=20 cars, we always just tightened the
> nut till there was no = side play=20 in the wheel but it still spun freely.
> I would think that = I'd want=20 it a little tighter in this application,
> since the forces = will be=20 trying to open up the rear seal and the only
> thing stopping = that=20 will be the preload...but I don't have a number to
> attach to = 'little=20 tighter'.
>
> >Again go to a bearing supply company, = I have=20 no doubt that there would be
a
> >standard seal to fit. = Who ever=20 made this PSRU would look for standard
seal
> = >sizes.
>=20 >
> >George ( down under)
> >
>=20 >
>
> Thank you, George.  I looked over Tracey's = website=20 (thank you, Tracey),
> and several other places.  I think = in the=20 application that this hub was
> meant for (a racecar wheel), = that the=20 car's wheel was the seal.  I have
> a 1/4" plate that = will=20 sandwich nicely between the prop and the hub.  I
> can = easily=20 machine a recess into it for a standard seal (I = think).
>
>=20 >>  Homepage:  http://www.flyrotary.com/
> = >>  Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
>



>>=  =20 Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
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