REFLECTOR: Need for Cabin Heat at Altitude

[Don Johnston]

I'm not sure I understand the requirement for a centrifugal fan. With the
outside entrance and exit closed, it's effectively a closed loop. There
doesn't appear to be significant resistance from the oil cooler. So as long
as the size of the input and output are similar, I don't understand why an
axial fan wouldn't accomplish adequate airflow to be effective.

-Don

On Tue, Jun 25, 2013 at 12:33 PM, Ruben Creus <ruben at vainneg.com> wrote:

> **
>
> We just did a similar thing than what is in the email below. We install an
> squirrel cage fan, and a flap on the oil scoop. Different tests show that
> for this magic trick to happen, there one very important requirement. And
> that is, *“a perfect seal*” around the flap. First, you need to build up
> air pressure in front of the oil cooler to force the air into the radiator.
> Second, a bilge fan cannot work under pressure, but a squirrel fan does. A
> *squirrel fan* is designed to work under air pressure losing just few
> CFM. A bilge fan will lose most of its CFM under pressure.****
>
> ** **
>
> I did a test in winter and summer, and finally installed it last week in
> with the help of the Sebastian folks. Scott did a super detail job there!
>  We achieved a perfect seal, and we are using a squirrel cage fan with
> 105CFM. The results were impressive. It blows a good amount of air, maybe
> 1/3 of what you would get with the flap open in flight, but it looks to be
> good enough to blow a good amount of air. But again, to build pressure in
> front of the radiator you need a perfect seal. Otherwise, air will escape,
> no pressure will built and all the effort will be a waste. Remember, * this
> can only work with a squirrel cage fan. A regular bilge fan cannot work
> under pressure.* ****
>
> ** **
>
> We hade in fact this Sunday a real test scenario, waiting on an airport
> for the clearance and the clear to take off, the oil temp started to go up,
> and there we go!!, we closed the flap and turn the fan on and the oil temp
> started to go down. So we had in group oil cooling!!! Now the question
> remains, will in the winter generate enough recirculation heat to heat the
> cabin in on the ground and in flight?   Our unorthodox tests of last winter
> say yes, but it is not until now we permanently mounted the solution, so
> when the cold weather comes back in few months I will report to the group
> the results, but it looks very promising. ****
>
> ** **
>
> Ruben****
>
> ** **
>  ------------------------------
>
> *From:* Don Johnston [mailto:numa at comcast.net]
> *Sent:* Sunday, June 23, 2013 8:24 PM
> *To:* ****Velocity** Aircraft Owners and Builders list**
> *Subject:* Re: REFLECTOR: Need for Cabin Heat at Altitude****
>
> ** **
>
> I don't know if it's going to work (since I'm not flying yet), but I've
> created a controllable door that will block off the outside air from the
> nose oil cooler which will allow inside cabin air to be passed through the
> oil cooler via a blower. Effectively heating cabin air instead of outside
> air.
>
> http://www.velocity-xl.com/blog/2008/06/14/12-3-6-nose-oil-cooler/
>
> http://www.velocity-xl.com/blog/2013/05/03/12-3-6-nose-oil-cooler-control/
>
> -Don****
>
> On Sun, Jun 23, 2013 at 7:15 PM, victor delta <vdelta at pacbell.net> wrote:*
> ***
>
> Looking for experiences, solutions, implementations,  ideas and otherwise
>  for requirement to assure reasonable cabin temperature/heat for passengers
> when flying in lower to mid flight levels ongoing.
> Especially welcome comments from those that fly their aircraft high most
> of the time, at night and/or during winter months.
> Thanks in advance for all contributions.
> VD
>
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> ** **
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