REFLECTOR: Cabin Heating

[Chuck Jensen]

The strip of duct tape will certainly slow down the total air flow some, but
it may not improve heat exchange much.  Where the duct tape strip sets on
the oil cooler face, the fins behind the tape have minimal opportunity to
add warmth to the air.  At the same time, the velocity of the air on both
sides of the tape may well be higher, thus negating its ability to grab heat
on it's way by.

A better solution may be to get a cloth bag filter (pool supply places have
them; they are used all the time for water processing) and cut rectangular
patches the approx. size of the front side of the cooler.  Use white duct
tape to secure the edges (but don't intrude onto the front of the cooler
much if you can help it).  The white duct tape and white bag filter will
virtually disappear.  Put two layers on for your first test.  That will
markedly slow down the air flow while allowing nominally 100% of the cooler
to be exposed for better heat exchange.  

You can further adjust engine oil/cabin temp by adding/removing layers.  For
a day in the 40-50F you may remove all but the first layer, for <0C day, you
might add a third or fourth layer.  It's manual but it looks good and works
will.

Chuck

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of jack davis
Sent: Wednesday, January 28, 2004 10:08 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR: Cabin Heating


I have done exactly this (i.e., fabricated a flapper valve that directs all
incoming air into the cabin).  You get very good heat when the engine is
running at 65% power or above and when the outside temperatures are above
about 15 degrees F.  Below that temperature, it is a bit cool in the cabin.
I also place a strip of duct tape across the front side of the oil cooler
(as Duane Swing suggests).

Jack
----- Original Message -----
From: "Jim Sower" <canarder@frontiernet.net>
To: <reflector@tvbf.org>
Sent: Wednesday, January 28, 2004 4:01 PM
Subject: Re: REFLECTOR: Cabin Heating


> It sounds like most of what we need is already in place.  My 173FG has the
front oil
> cooler in a plenum.  The input to the plenum is the NACA in the nose, and
it exhausts
> out the bottom of the plenum.  I have a 2" duct out the back of the plenum
going to
> the cabin foot warmers (could be larger and go to more places).  As it
stands now,
> only the (tiny bit of) exhaust from the oil cooler that doesn't go
overboard goes into
> the heat system.  I aim going to make a flapper valve that can cover
either the outlet
> to the cabin completely or the overboard opening completely or anything in
between.
>
> If it's really cold, I'll block the overboard vent and the only air that
passes
> through the oil cooler will be whatever the outlet to the cabin will
permit.  Air flow
> will be much reduced and therefore much hotter.  If I don't need that much
heat, I can
> crack the overboard vent which will increase flow through the cooler but
reduce flow
> into the cabin (the rest going over the side).  I can keep venting the
overboard vent
> more and more until I have the cabin vent blocked and all the air the
cooler will pass
> going over the side.  One flapper valve, a plenum that's already there, no
additional
> oil coolers.  I may have to make a new plenum so the flapper will fit
between the
> cooler and cabin outlet bulkhead and be big enough to cover the overboard
vent, but
> that's not rocket science.
>
> Limiting air flow to the hot air I need should make for enough delta-T to
heat the
> cabin, and increasing air flow as my heating requirements go down will
tend to match
> increased oil cooling requirements.
>
> Just a theory ... Jim S.
>
> Dave Black wrote:
>
> > Scott,
> >
> > > I think if you had the nose oil radiator and an inside one for cabin
> > > heating you could easily run them in series, much easier plumbing.
> > >
> > > Then close off the cabin heat outlets on the oil cooler duct.  If your
oil
> > > is too cool just close the flap(that used to direct the air into the
cabin)
> > > a bit thus reducing the flow through the radiator and raising the oil
> > > temps, good for the engine and for the passengers too.
> >
> > You may be on to something! It would be stone simple plumbing. And I
believe
> > it would be a huge improvement over the standard nose cooler only
> > installation.
> >
> > I see two drawbacks:
> >
> > 1) The total length of the oil line. The longer the line, the more
'congealed
> > oil plug' effect you have in cold weather. But now that I think of it,
with
> > this system, there'd be absolutely no need to leave the original cooler
in the
> > nose. Rather, it should be relocated to the engine compartment. Hence
the
> > total plumbing could be MUCH shorter than the standard system.
> >
> > 2) The cabin heater would always be hot, even in summer. However I'm
certain
> > that with some clever design, most of the unwanted heat from the cabin
heater
> > during the summer can be contained, blocked from entering the cabin, or
ported
> > overboard. Heck, if the unwanted heat can be eliminated efficiently, the
cabin
> > heater could even be used during summer as an auxiliary oil cooler.
There are
> > certainly times when that would be a good thing.
> >
> > All-in-all, I believe two coolers in series with no valves is a big
> > improvement over the standard system. Certainly it'd be a very simple to
> > plumb, and cabin temperature control becomes a matter of controlling a
blower
> > motor and flapper(s).
> >
> > I guess a flapper valve located in the cabin floor could direct hot air
either
> > back into the cabin or overboard. It needs to work quite effectively to
keep
> > the cabin from getting hot in summer. But I'll bet it could be done. On
the
> > other hand, putting a bypass valve around the cabin heater would keep
the heat
> > out too.
> >
> > Hmmm...
> >
> > Dave Black
> > Shortwing RG
>
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