REFLECTOR: Cabin Heating

Scott reflector@tvbf.org
Tue, 27 Jan 2004 21:57:12 -0700


Chuck,

I also have the heater configuration that you do and that 99% of every 
other V does.

I froze my ass off flying my just purchased airplane from Florida back to 
NM.  OAT's were sub zero Fahrenheit.

I went about the cure from a different angle.  First close off the numerous 
air leaks. And there were quite a few.  First the door leaks, at least the 
ones that blew cold air in.  That helped a lot.  Then the elevator torque 
tubes, that helped a whole lot. Misc leaks around the dog house door, 
etc,  Helped a bit more.  It was getting better but I still have a huge 
leak where the nose gear strut pivots in the keel.  I plan on sealing that 
during my ongoing nose gear rebuild.

I can now keep the cabin warm if the OAT is above 15/20 Fahrenheit.

Ithen  noticed the passenger heat was quite a bit cooler, sometimes even 
cool when the pilot heat was warm.  The passenger heat has to travel 
through a flexible duct from the oil cooler duct up around the nose gear to 
get to the passenger inlet.  I replaced that duct with the really thick, 
double walled ducting, that made a huge difference.  I was amazed at how much.

I think the cabin can be heated with the oil cooler but the it requires a 
tight cabin.

Scott

Still fixing cabin air leaks....  BTW, flying my late Bonanza in the winter 
was a cold ride with an exhaust muff heater..  Musta been the air leaks!

At 07:19 AM 1/27/2004, you wrote:
>Since every configuration is different, yours may vary but I tried some of
>your proposed fixes with less than stellar results. My cabin air is fed from
>a flapper that opens and taps air flow downstream plenum of the front oil
>cooler and ducts it to the cabin.  It was obvious, due to the massive
>airflow thru the oil cooler, the outlet discharge air was heated just a few
>degrees.  Figuring that by slowing the air flow, the increased residence
>time would allow sufficient heating of the air, I cut some squares of a
>cloth bag filter and put 4 layers over the cooler inlet and plugged the
>plenum outlet.  The only air allowed to pass was what I feed to the cabin.
>My plan was to rely on the rear oil cooler to maintain engine oil temps.
>
>On the test flight at OAT 5C, the cabin heat was nice and toasty; a big
>improvements (and a high "smug" factor).  Then the oil temps started to
>climb, and climb.  Finally topping out at 220C (181C is normal) and elevated
>CHTs at reduced cruise.  End of experiment.  Removed the outlet plug and 2
>of the 4 cloth layers on the inlet and went back to freezing at 0C OAT.  It
>was unexpected (in my mind) that the front oil cooler carried that large a
>fraction of the cooling load.  I expected to be able to block off the front
>cooler and still maintain adequate oil temperatures. Not. There just doesn't
>seem to be a happy medium.
>
>Bottom line; I'm going to try a second oil cooler, in series with the front
>cooler, that's dedicated solely to cabin heat.
>
>Chuck
>
>Jim S. wrote:
>
>I have the same problem with my 173 FG.  I have outlets to the cabin in the
>outlet
>plenum of the forward oil cooler, but not much air goes there if it can get
>out the
>bottom scoop.  I plan on making a "flapper valve" that in one position
>covers the
>outlets to the cabin, and in the other position covers the overboard vent.
>That will
>force all the air coming through the forward cooler into the cabin.  Of
>course that's
>continually heating outside air, so if it still doesn't work, I'll fix it so
>when I
>open the vents to the cabin and close the overboard vent, it will also close
>off the
>inlet and turn on a blower that recirculates cabin air through the forward
>cooler.
>I'm not worried about not being able to cool the oil since this only happens
>in the
>dead of winter when the aft cooler should be able to do the job by itself.
>Fix it next summer, try it next winter .... Jim S.
>
>Chuck Jensen wrote:
>
> > Jack,
> >
> > I get the same speed in the XL RG...if I have about an 80kt tailwind!!!  I
> > too am going thru the "I tired of freezing to death and I'm not going to
> > take it any more."  I'm going to try tapping into the oil line to the
>front
> > cooler and route it to a cooler in a plenum in the nose so the air flow
>can
> > slow down and absorb the heat or I'll route it to a oil cooler in the
>cabin
> > and use a fan to blow air across it.
> >
> > No doubt about it, the heated seats and nice blanket doesn't cut it at
>-8C.
> > It feels like a meat locker.  When I blocked off enough air flow through
>the
> > front oil cooler, it heated up the air nice, but the engine oil temp went
>up
> > 30F.  I don't know what I'm doing, but I'm doing it!!!
> >
> > Want a cheap speed increase...gap seals were the answer for me.  I gained
>an
> > easy 5 kts and maybe as much as 8-9kts with a $5 gap seal kit, though it
> > doesn't help aileron responsiveness any!
> >
> > Chuck
> >
> > -----Original Message-----
> > From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> > Behalf Of Jack Sheehan
> > Sent: Monday, January 26, 2004 2:03 PM
> > To: reflector@tvbf.org
> > Subject: Re: REFLECTOR: Vortilons
> >
> > Wow ! So much discussion VG's Vortillons , Trailing edge fences. I
> > must be nuts. I have about 150 Hours on my XL-RG I did the test
> > flying without anything. It flew great. I painted the airplane and it
> > flew better. ( guess I just got better). I have looked at all the
> > stuff and am reluctant to make any changes because the wing just
> > looks good clean. The airplane gets a little sloppy below 100 knots
> > with the gear down. You have to use the rudders to lead the turn and
> > the aileron inputs are very deliberate. The problem I have is I am so
> > used to it everything feels OK. I plan to install the vortillons and
> > see if that makes a big change and then put on some trailing edge
> > fences to see if that does anything. I would remove anything that
> > effects the top end. I would rather go fast.
> > The only other modification I would be looking to do would be to get
> > some more heat in the airplane. On a trip back from Kentucky last
> > week I was really cold OAT -8C @  FL 015 but the ground speed was 260
> > KTS 285 in the decent.
> > Jack
> > N55XL
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>--
>Jim Sower ... Destiny's Plaything
>Crossville, TN; Chapter 5
>Long-EZ N83RT, Velocity N4095T
>
>
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