Message-Id: <5.1.1.5.2.20040505134327.0238e928@localhost>
Date: Wed, 05 May 2004 14:06:48 -0500
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
From: Mark Steitle <msteitle@mail.utexas.edu>
Subject: Re: [FlyRotary] Re: Coolant Pressure Gauge
In-Reply-To: <list-3207524@logan.com>
Mime-Version: 1.0
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Well, that's interesting.  This reminds me of a nagging question I have 
had, but haven't asked.

I was curious about the need to go to a smaller crank pulley to slow down 
the water pump and alternators.
 From memory, the crank pulley is about 5-1/2", the alternator pulleys are 
about 2-1/2", and the water pump
pulley is about 4" diameter.

So, running an RD-2C (2.85 ratio), the alternators will be turning about 
20k during climb-out and the wp will be turning
about 10K rpm.  That seems too fast to me.  I could probably find larger 
pulleys for the alternators, but
then there's the water pump pulley.  Your unplanned experiment would 
suggest that we can run the wp slower
and still cool adequately.

This brings me to a second option.  I think a simpler approach would be to 
reduce the size of the crank pulley.
The problem is that I haven't found a multi-V reducing pulley at any of the 
after-market suppliers.  I really don't
want to change over all the multi-V pulleys to single V pulleys, but that 
is one option.

Another solution might be to find a smaller pulley from another vehicle and 
adapt it to fit the rotary.  If that doesn't
work, I could have one made.

So, am I worrying about nothing, or is this a real problem?

Mark


      At 02:26 PM 5/5/2004 -0400, you wrote:
>Actually, Mark,  I did not notice any variance in the cooling system from
>the normal.  I just checked my flight log for that trip and at cruise my oil
>and coolant ranged from 160-170F which is normal.  I too  would have thought
>that as loose as the belts were (I could easily turn the water pump against
>the belt friction by hand) that the water pump would have slowed down
>sufficiently to have elevated the coolant temp.  But, it apparently did not.
>
>Perhaps another way of looking at it is in regards to the power needed to
>drive sufficient coolant, apparently not very much which corresponds well
>with the 1/3 - 1/2 HP of the EWPs.
>
>Ed
>.
>Ed Anderson
>RV-6A N494BW Rotary Powered
>Matthews, NC
>----- Original Message -----
>From: "Mark Steitle" <msteitle@mail.utexas.edu>
>To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
>Sent: Wednesday, May 05, 2004 8:57 AM
>Subject: [FlyRotary] Re: Coolant Pressure Gauge
>
>
> > Ed,
> > You reported a loose alternator/water pump belt(s) while on your way back
> > from SNF causing the alternator field breaker to trip.  Did you notice any
> > changes in water pressure that could be associated with the loose
> > alternator belts?
> >
> > Mark S.
> >
> >
> > At 08:09 AM 5/5/2004 -0400, you wrote:
> > >Steve,
> > >
> > >     I use a 0-30 psi fuel pressure sensor and gauge for my coolant
>pressure
> > >sensor and its still working fine after close to 300 hours.  At one time
> > >(and they may still do) UMA offered a coolant (or water) pressure gauge
>so
> > >marked - they actually silk screened a new placard and placed it in the
>fuel
> > >gauge I purchased from them.  So my fuel gauge actually says "Water
> > >Pressure"
> > >
> > >    The coolant gauge gives you pressure information that you soon begin
>to
> > >correlate with your coolant temperature as well as OAT.  You soon begin
>to
> > >notice when anything departs from the norm.  Its simple another bit of
> > >information about your system which does nothing for you most of the time
> > >but provide that comfort level that things are nominal - but, can alert
>you
> > >to departures from the nominal which bear investigating.
> > >
> > >
> > >Ed
> > >
> > >Ed Anderson
> > >RV-6A N494BW Rotary Powered
> > >Matthews, NC
> > >----- Original Message -----
> > >From: "Steve Brooks" <steve@tsisp.com>
> > >To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > >Sent: Wednesday, May 05, 2004 7:18 AM
> > >Subject: [FlyRotary] Re: Mystery of the leaking coolant
> > >
> > >
> > > > Yes, it does sound like a good idea.  I've looked for a sender and
>gauge,
> > > > but haven't found any.  Does anyone have a good source for these ?
> > > >
> > > > Steve Brooks
> > > >
> > > > -----Original Message-----
> > > > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
> > > > Behalf Of Bill Dube
> > > > Sent: Tuesday, May 04, 2004 9:04 PM
> > > > To: Rotary motors in aircraft
> > > > Subject: [FlyRotary] Re: Mystery of the leaking coolant
> > > >
> > > >
> > > >
> > > > >
> > > > >With the overflow plugged it was probably building up some pretty
>good
> > > > >pressure, which I'm sure led to the failure of the pump seal.  It is
>such
> > > > an
> > > > >odd thing to have happened, but I'm glad that my days of chasing the
> > >drips
> > > > >of coolant are over.  I think that the hoses must be there to stay,
>since
> > > > >they didn't blow off.
> > > >
> > > >          In "The Book" Tracy strongly suggests installing a coolant
>system
> > > > pressure gauge. It sounds like it might be a good suggestion, in light
>of
> > > > the trouble you had.
> > > >
> > > >
> > > >
> > > > >>  Homepage:  http://www.flyrotary.com/
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> > > >
> > > >
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> > > >
> > >
> > >
> > >
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> >
> >
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>
>
>
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