NoahBryant

How to cool the cabin?

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Texas was warm today, 85 degrees. Used to the Connie, I decided to start the #3 early to get the cabin cool but realized I had no idea how to cool the cabin of the DC-6. I've been trying for more than an hour now. Heat works fine if I want to give my passengers heat stroke, but cannot figure out a way to cool the cabin down.  

Turbine is on, the thermostat is all the way to cool and the Cabin Temp Mix Valve Position is fully cool. I tried using AFE for everything just to make sure I wasn't missing anything. 

What'd I miss?

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You have to start #4 or #1 engine to start the cabin superchargers for it to cool down. I haven't figured out how to cool it down, but that's a start.

K S Kolashinski 

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Does the dc6 actually have the capability to provide cooler than ambient air?

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2 hours ago, Pilot53 said:

Does the dc6 actually have the capability to provide cooler than ambient air?

Yep.  From Jon Proctor's (excellent) book, From Props to Jets...

Quote

...the DC-6 had the first cabin heated by radiant heat in the cabin walls and floor... it was the first airliner to be air conditioned both in the air and on the ground.

Here are the relevant pages.

Delta also gives the air conditioning a shoutout on its DC-6 fleet history page.

Quote

"Our passenger comfort didn't really become obvious or actual until the DC-6, and that was due to the pressurization and air conditioning."  Art Ford, Delta engineer 

Oh, and this is fun - the 1948 Delta DC-6 brochure.

In all, quite the step forward.

 

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So is this just not modeled? It's weird that cabin heating would be modeled but not cooling?

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10 hours ago, NoahBryant said:

So is this just not modeled? It's weird that cabin heating would be modeled but not cooling?

There's an interesting excerpt in the POH about it.

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12 hours ago, NoahBryant said:

So is this just not modeled? It's weird that cabin heating would be modeled but not cooling?

Why do you think the modeling is incorrect?  The cooling turbine will only provide marginal cooling on the ground, it is not a refrigerant-based system system like your car but an air cycle engine that cools warm air getting it to do work and expanding in a turbine.  I think the POH says you might get 15 deg cooling if the humidity is low.

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To add to what Dan said above - see POH, pg. 138-139: "Depending on O.A.T. and cabin temperature requirements, the mixing valve mixes the air from any two adjacent ports in the proper proportion to provide tempered air, as required, to maintain cabin temperature within the limits of 65°F to 85°F. The cooling turbine has a limited capacity, but is capable of holding cabin temperature approximately 15°F below O.A.T., provided excessive humidity is not encountered."

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Thanks very much for the response Kyle, Dan and Henning. I apologize for not being more detailed in the beginning as I was simply asking what I was doing wrong. At the time, I had an 85 degree OAT and it was 85 degrees in the pax cabin. I took off and even by 10,000 feet it was still 85 in the cabin. 

I just now conducted two different tests. First, I loaded the sim with the DC6 at KLAX where the temp is currently 84. As soon as the sim loaded (since it sadly loads with the engine running) I looked at the cabin temp and it was dropping from 80 and went down to the low 70s (Exactly as the manual states). 

I then set the plane to cold and dark, as I always do. Immediately the cabin temp rose to 84 degrees in about 20 seconds. 

Then, I went through my startup procedure as I always do and once the engines were running and the turbine was switched on, the cabin temp never changed. I throttle the engines up - still no change in cabin temp. 

So once again, I am just asking what I am doing wrong because although the manual does talk about cabin cooling, it neglects to actually say how to do it. Based on my above tests, I am nearly positive I am the one that's doing something wrong and I am just asking for help. 

Edit - Actually never mind. Although the cabin temp goes down when you first load the sim, if you wait a few seconds it climbs back up. So I have no idea how it's supposed to work so I am just asking for help. 

 

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Noah, I'm not sure if the cooling turbine is effective while on the ground. The engines are idling and the cabin supercharger is not putting out much volume of air. As an engineer I would be impressed if it was effective under those conditions.  The small twin I fly has refriderant cooling run from an electrical motor instead of off the engine like your car and we still don't get much cooling on the ramp.  It makes all the difference in the world to get up to 14,000 ft.

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15 hours ago, downscc said:

Noah, I'm not sure if the cooling turbine is effective while on the ground. The engines are idling and the cabin supercharger is not putting out much volume of air. As an engineer I would be impressed if it was effective under those conditions.  The small twin I fly has refriderant cooling run from an electrical motor instead of off the engine like your car and we still don't get much cooling on the ramp.  It makes all the difference in the world to get up to 14,000 ft.

Lucky you, my C152's cabin is cooled by a vent open to the outside air. It get's insanely hot in summer here on the ground, there's always a desperate rush to get in the air just to get some airflow through the cabin!

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