Return-Path: Received: from [65.54.168.121] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 760742 for flyrotary@lancaironline.net; Sat, 26 Feb 2005 13:45:47 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.168.121; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 26 Feb 2005 10:45:00 -0800 Message-ID: Received: from 4.174.5.166 by BAY3-DAV17.phx.gbl with DAV; Sat, 26 Feb 2005 18:44:42 +0000 X-Originating-IP: [4.174.5.166] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Belts Date: Sat, 26 Feb 2005 13:44:39 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0056_01C51C09.512E0120" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Sat, 26 Feb 2005 13:44:39 -0500 X-OriginalArrivalTime: 26 Feb 2005 18:45:00.0852 (UTC) FILETIME=[46E91F40:01C51C33] This is a multi-part message in MIME format. ------=_NextPart_000_0056_01C51C09.512E0120 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Good points. I can't get excited about eliminating belts because I = have never seen even a hint of a problem with them * when properly = installed *. This includes all experience with cars and aircraft.=20 I *have* seen them fail when pulleys were not properly aligned, debris = or damage caused the pulley to wobble, they were overloaded, or other = installation errors. Belts are a very mature and reliable technology. There may be good = reasons to replace a belt but reliability is not one of them. Tracy Crook As a public service announcement... Please change the post topic to fit your post. It just makes sense. = Get creative! Make a new Subject Title! A question about belts; what are the race guys doing? Do they see = belt failures? Is Tracy using a belt? Ever failed? I admit I feel more comfortable without belts, but we should be = deciding this on facts not feelings. I don't have any facts. I understand many automotive overhead cams use belts. A failure will = (if interference engine) bend valves and break pistons. These belts must = be a well known quantity. I perceive the "danger"of a belt is the potential cascading failure. = Belt failure takes out alt and water pump and air-conditioning (if your = John Slade). But i guess, if this case is sufficiently rare then a = secondary alt and water pump not effected by this event will serve as a back up = allowing us to complete the flight. To argue the other side of the coin, not using the automotive water = and alt system is throwing away cheap well engineered and proven, easy to use = system away, to get something we "feel" is better. Remember, the most common failure of auto conversations is the supporting systems. Eric From: "Marvin Kaye" > Here's some general drive belt data from CarCareCouncil.org. It = pretty well > sums up the v-belt vs serpentine question: > > """ > Description: Fan belt is the traditional term for what today is = called a drive > belt. Drive belts are made of reinforced, high-tensile strength = cords and > synthetic rubber. They connect the engine to front-mounted = accessories. Belts > come in two different types: The traditional V-belt (cross-section = of belts > has a V-shape for V-shaped pulleys) and the serpentine belt (also = called > Poly-V, Poly-Rib, Multi-Rib, and Micro-V belt), which uses multiple = Vs for > more positive contact with its mating pulleys. > > Purpose: Drive belts provide power to engine-mounted accessories = like the > power steering pump, air conditioning compressor, mechanical cooling = fan, and > air injection pump. Serpentine belts are now used on almost all = vehicles. > > Maintenance Tips/Suggestions: Studies show that the chances of a = drive belt > failure rises dramatically after four years or 36,000 miles for = V-belts, > 50,000 miles for serpentine belts. This doesn?t mean that the belts shouldn?t > be inspected before then, though. The belts should be checked every = time the > oil is changed to make sure they?re OK and properly tightened. When checking > V-belts, a slipping belt usually has shiny sidewalls (glazing) = caused by heat > from sliding in the pulleys. The glazing often causes a chattering, slapping > or squealing noise. And, because the glazing hardens the belt, it's = prone to > cracking and early failure. Belt slippage often occurs because of = low tension, > the wrong belt, or grease or oil. Missing chunks, or separating = layers of the > belt often hint at a dousing of oil or grease. The source of the oil = or grease > needs to be corrected before installing a new belt. A V-belt with = any of these > conditions should be replaced as soon as possible. On serpentine = belts, > inspect the belt closely for any cracks in the ribbed area. Also = check the > backside of the belt for grooves, fraying, or splitting. Although = random > cracks across the ribs are a sign of normal belt wear and don?t mean = the belt > will fail immediately, it?s a good idea to replace the belt the next = time your > car is serviced. > """ >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0056_01C51C09.512E0120 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Good points.   I can't get excited about eliminating = belts=20 because I have never seen even a hint of a problem with them   = * when=20 properly installed *.  This includes all experience with cars and=20 aircraft. 
 
I *have* seen them fail when pulleys were not properly aligned, = debris or=20 damage caused the pulley to wobble, they were overloaded, or other = installation=20 errors.
 
Belts are a very mature and reliable technology.  There = may be=20 good reasons to replace a belt but reliability is not one of them.
 
Tracy Crook
As=20 a public service announcement...
Please change the post topic to = fit your=20 post.  It just makes sense.  Get
creative!  Make a = new=20 Subject Title!

A question about belts; what are the race guys=20 doing?  Do they see belt
failures? Is Tracy using a = belt?  Ever=20 failed?

I admit I feel more comfortable without belts, but we = should be=20 deciding
this on facts not feelings.  I don't have any = facts.

I=20 understand many automotive overhead cams use belts.  A failure = will=20 (if
interference engine) bend valves and break pistons.  These = belts=20 must be a
well known quantity.

I perceive the "danger"of a = belt is=20 the potential cascading failure.  Belt
failure takes out alt = and water=20 pump and air-conditioning (if your John
Slade).  But i guess, = if this=20 case is sufficiently rare then a secondary alt
and water pump not = effected=20 by this event will serve as a back up allowing
us to complete the=20 flight.

To argue the other side of the coin, not using the = automotive=20 water and alt
system is throwing away cheap well engineered and = proven,=20 easy to use system
away, to get something we "feel" is = better. =20 Remember, the most common
failure of auto conversations is the = supporting=20 systems.

Eric

From: "Marvin Kaye"
> Here's some = general=20 drive belt data from CarCareCouncil.org.  It = pretty
well
> sums=20 up the v-belt vs serpentine question:
>
> """
> = Description:=20 Fan belt is the traditional term for what today is called = a
drive
>=20 belt. Drive belts are made of reinforced, high-tensile strength cords=20 and
> synthetic rubber. They connect the engine to front-mounted = accessories.
Belts
> come in two different types: The = traditional=20 V-belt (cross-section of
belts
> has a V-shape for V-shaped = pulleys)=20 and the serpentine belt (also called
> Poly-V, Poly-Rib, = Multi-Rib, and=20 Micro-V belt), which uses multiple Vs for
> more positive = contact with=20 its mating pulleys.
>
> Purpose: Drive belts provide power = to=20 engine-mounted accessories like the
> power steering pump, air=20 conditioning compressor, mechanical cooling fan,
and
> air = injection=20 pump. Serpentine belts are now used on almost all = vehicles.
>
>=20 Maintenance Tips/Suggestions: Studies show that the chances of a=20 drive
belt
> failure rises dramatically after four years or = 36,000=20 miles for V-belts,
> 50,000 miles for serpentine belts. This = doesn?t=20 mean that the belts
shouldn?t
> be inspected before then, = though. The=20 belts should be checked every time
the
> oil is changed to = make sure=20 they?re OK and properly tightened. When
checking
> V-belts, a = slipping belt usually has shiny sidewalls (glazing) caused = by
heat
>=20 from sliding in the pulleys. The glazing often causes a=20 chattering,
slapping
> or squealing noise. And, because the = glazing=20 hardens the belt, it's prone
to
> cracking and early failure. = Belt=20 slippage often occurs because of low
tension,
> the wrong = belt, or=20 grease or oil. Missing chunks, or separating layers of
the
> = belt=20 often hint at a dousing of oil or grease. The source of the oil=20 or
grease
> needs to be corrected before installing a new = belt. A=20 V-belt with any of
these
> conditions should be replaced as = soon as=20 possible. On serpentine belts,
> inspect the belt closely for = any cracks=20 in the ribbed area. Also check the
> backside of the belt for = grooves,=20 fraying, or splitting. Although random
> cracks across the ribs = are a=20 sign of normal belt wear and don?t mean the
belt
> will fail=20 immediately, it?s a good idea to replace the belt the next=20 time
your
> car is serviced.
>=20 """



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