REFLECTOR: Cold Weather Flying

[Laurence Coen]

John,

The carburetor has a 1/8" pipe thread fitting for the mounting of a 
temperature probe.  It places the probe in the throat of the carburetor 
where ice tends to form.  That is where mine is and it works fine.  One of 
the things that I thought of trying were temperature sensing linear 
actuators that are used to open and close vent windows on greenhouses.  If 
they were used to operate dampers in the plenum plumbing you'd have 
automatic thermostatic control.  After 10 years of tinkering I decided to go 
flying instead.

Larry Coen
N136LC

--------------------------------------------------
From: "John Dibble" <aminetech at bluefrog.com>
Sent: Friday, December 21, 2012 10:04 AM
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Subject: REFLECTOR: Cold Weather Flying

> Had a good flight from MS to NY on Wednesday.  Stopped at DKX Knoxville
> for fuel.  That's a hard airport to find hidden in the hills.  A while
> back I reported that my temps were too low in cold weather and not
> enought cabin heat.  I decided to go after the source of the heat and
> reduce the engine cooling air, see pic.  I thought this would be over
> kill and I would have to trim it a bit, but it turns out that this just
> gets the engine temps to the bottom of the desired range (250-300F) with
> an OAT of 40 F.  At 30F CHTs are 240-245F.  Still, the oil temp ran at
> 275F with the diverter flap fully deployed and that gave too much cabin
> heat.  During descent for landing, temps got very low and I had no cabin
> heat.  I would like to have a way to adjust engine cooling air from the
> cabin, so I can have max cooling for T/O and reduce cooing air at cruise
> and reduce it further for descent.  Has anyone done this?
> When the OAT got down to 30F, I decided it would be a good idea to add
> some carb heat even though my manifold pressure was holding steady.  I
> did not see an expected increase in the carb temp gauge, but the MP did
> decrease by a few tenths indicating that the carb heat was working.
> Guess I need to work more on the the carb temp sensor placement.  I had
> moved it to the fitting where the manifold pressure line connects (carb
> outlet).  It seemed to be giving sensible readings at higher OATs, but
> not at 30 F where it counts. Looking forward to returning to warmer
> weather after the holidays.
>
> John
>
>
>



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