REFLECTOR: Re: Cabin Heating

Wed Feb 22 18:36:11 CST 2006

Every high performance complex general aviation aircraft that I can think 
of, has cowl flaps. They are not only important for summer and winter 
operation but for high altitude operation. You can actually hurt your engine 
from to much cooling. The choke in our cylinders is there for a reason. It 
is intended to allow the cylinders to become a straight bore when the 
cylinder temperature is at the correct operating temperatures. If you are 
running your engine too cool, you could be prematurely warring out your 
rings and cylinders. There is a very easy way that I see that a butterfly 
type valve could be added to the NACA scoops. These two butterfly valves 
could be controlled by a push pull cable located inside of the ceiling fresh 
air duct, having a lawn mower type throttle control also mounted in the 
overhead duct. I flew a 1964 M20E for 15 years that had the original 
oversized air intake. I was able to control my oil temp using the cowl flaps 
very easily. I was going to draw all a diagram of the NACA butterfly valve 
that I have in mind, but didn't have time today. Remember the Butterfly 
valve shouldn't completely close off the air, only provide control over 
restricting air flow. So the valve in the closed position shouldn't block 
any more than about 30% of the air flow.

My thoughts.

Andy Ellzey

----- Original Message ----- 
From: "Rene Dugas" <dugasd at bellsouth.net>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Wednesday, February 22, 2006 5:24 PM
Subject: RE: REFLECTOR: Re: Cabin Heating

> Ron,
> The variable floor NACA's might be easy to build but I would think they
> would be difficult to seal to maintain high pressure above the engine
> and low pressure below for cooling.  Just blocking off the oil coolers
> has worked well for me and is KISS.  I know we are experimenters but
> engines are expensive.  What we want is a cool engine and hotter oil
> temps.  A closed air flow through the front oil cooler and back inside
> driven by a bilge pump fan is my next project for winter.  Recycling
> warming air should work and adding a little cool air from the overheads
> is usually the most comfortable and pretty simple.  I'm looking for a
> 1.5 inch bilge fan to make it easy to place inline with my heating
> system.  I am already wired.
> Your mileage may vary.
> Rene'
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Ron Brown
> Sent: Wednesday, February 22, 2006 9:17 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Re: Cabin Heating
>
>
> I still think it would be OK to make some NACA scoop inserts to use for
> cold
> weather (less than 20-25 degrees which is when the Vernatherm seems to
> stop
> sending hot oil to the cooler).  These would just slip into the NACA and
>
> reduce the opening by say 1/4 to 1/3.  They could be held in place with
> a
> couple of screws in the front, the back being held in place by the NACA
> opening.
>
> Another approach is to use variable floor ramps in the NACA.  Vlad had
> built
> some for his Velocity a while back, but he still isn't flying.
> Basically,
> the bottom of the NACA opening was hinged at the front with a mechanism
> to
> raise the rear portion upward to reduce the airflow.  As with any cowl
> flaps, you would need to monitor engine temps.  With modern (like GRT
> EIS or
> other engine monitors) a high CHT alarm could alert to open the NACA
> ramp.
> With the removable insert, just watch temps on the climb out and lower
> the
> nose when the CHT's get too high.
>
> The variable bottom on the NACA should be pretty easy to implement for
> those
> of you who live in the frigid north and are still building.
>
> Ronnie Brown
> Cornelius, NC - in the not-so-frigid Southeast.
>
>
> ----- Original Message ----- 
> From: "Dr. Golf" <drgolf369 at yahoo.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Wednesday, February 22, 2006 9:21 AM
> Subject: Re: REFLECTOR: Re: Cabin Heat 12 volt
>
>
>>I have been working on keeping the draft out. The boys
>> at velocity helped install a rubber seal around the
>> nose gear where it exits the cabin. I installed
>> inflatable (electric pump)door seals and they work
>> perfectly (quiet also). I have recently covered the
>> opening in the keel around the canard control rod with
>> 1" insulating foam rubber (not too tight). I placed
>> the same foam on the back of the rear cabin panel (
>> not the firewall) and snugged it tight where it
>> contacts the cabin walls, top and floor. I placed a
>> vinyl cover over the back of the instruments drapping
>> it forward to the front of the canard.I created a
>> silicon seal around the canard cover.
>>
>> When the engine pumps the oil to the oil cooler in the
>> nose, I am as warm as a bug in a rug, but because of
>> the oversized scoops, this is tough to do in the cold
>> weather  without exceeding 200 knts.
>>
>> My next project is to create a seal between the nose
>> gear doors.
>>
>> Your description of the blanket sounds great!
>>
>> Any other suggestions?
>>
>> Perhaps if we kidnap Dwayne and the Scotts and make
>> them fly with us in the freezing north, I bet within 2
>> weeks, there will be mods avaiable to practically
>> pressurize the cabin! What do you think?
>>
>>
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