Adding AC to EXP-AB plane

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docmirror

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Now that it's getting cooler, I'm forgetting all the days in summer when I was baking on the ramp trying to keep us cool. Since I'm going to look for an EXP plane next go around, I was also considering the option of making up some kind of engine driven AC.

I have an evap cooler in my plane now, and on dry days it helps considerably, as well as helping at altitude. But - we all know that no kind of evap or ice system is going to really do the job of a Freon based AC system.

So - I gave it some thought and the trials of adding AC to a small EXP plane, might be too hard to overcome.

I started with the Sonex as a base with the VW engine driving their standard wood prop. Since it has a prop flange with bolts, I figure a belt drive could be adapted behind the prop to drive a pump set down or up off to the side. I was thinking of using a square hole in the rear baffle for the condensor, like is found on oil coolers and the standard Geo Metro evap mounted under the panel with a couple of 12V blowers.

wonder what the weight of the system would be if I used the tiny pump off a Geo metro, and a boxed condensor, and the standard Geo evap unit? Also wonder how effective it would be? Of course, I'd block off the area behind the seats and make sure my canopy had a good seal also. I don't think it would take up that much weight, but surely it would be over 25Lbs I'm guessing with the lines and stuff.

Any other ideas like this? Places or products I haven't thought of? I was considering one of the self-contained units that have a hot exhaust duct, but they take up a lot of room.
 
40 to 50 lbs and the condenser needs to be in cool air not air that has been heated by the engine to work well. The hotter the air temperature the higher the head pressure will be on your compressor. I would guess it will take about ten horsepower to run the compressor.
 
Depends which compressor you use. I doubt you can manage less than about 22lbs. I also think you don't have sufficient room for the condenser size you need, and placing it in the hottest area of the plane doesn't make a lot of sense.
 
A small Sanden will only take about 2 HP, 3 at most.

http://www.sanden.com/objects/SD5H09_Performance.pdf

I'd agree with the 40-50 lb estimate for total system weight. Yes, condenser needs to get cold air. You could mount it like an additional oil cooler and that ought to work. Don't forget it'll need a fan to be effective on the ground.

You could also go with a full electric system, which would be another optino and probably what I'd consider.
 
Do a Goggle search, but there was one system that used electrical components from a hybrid car.
 
On the condensor location it would above the cylinder at the back of the engine in blast air area. Thats about as cool as its going to get. Thats where the oil coolers sit. I was thinking of a duct above the cowl out in the slip stram but I dont think that would be any cooler air.

50 lbs would be too high. I'm gonna weigh the pump and evap and some lines and see where I'm at. Adding the pulley and brace weight might get it near 40 but I dont think it will be that high. Those Metro pumps are tiny! Any other ideas just let me know.
 
All the piston planes that I've seen with AC had it removed.

IMO unless you're putting a turbine on it, AC isn't a good "upgrade", especially for a small bore piston plane.

I have a IO520, 300hp, all legal FAR stuff aside, I'd never dream of putting all that hardware on my engine, and that's coming from a guy who has lived in the desert and the savannah.

Keep your ice box cooler and call it a day.


If you MUST do it, go electric.
 
Need a p51esque belly scoop for cool air and hiding heavy stuff.
 
ClimbnSink said:
Need a p51esque belly scoop for cool air and hiding heavy stuff.
Click to expand...

I don't recall who makes it, but a scoop like that is what is used to duct air to the condenser on the Lancair I occasionally work on. I've never heard the owner complain about the A/C system, so it must be a decent setup.
 
docmirror said:
On the condensor location it would above the cylinder at the back of the engine in blast air area. Thats about as cool as its going to get. Thats where the oil coolers sit. I was thinking of a duct above the cowl out in the slip stram but I dont think that would be any cooler air.

50 lbs would be too high. I'm gonna weigh the pump and evap and some lines and see where I'm at. Adding the pulley and brace weight might get it near 40 but I dont think it will be that high. Those Metro pumps are tiny! Any other ideas just let me know.
Click to expand...

The aircraft systems I see mount the condenser in the back of the cabin sector, you can build a little P-51 scoop for it.
 
Last edited:
James331 said:
All the piston planes that I've seen with AC had it removed.
Click to expand...

Then you clearly haven't spent much time around Twin Cessnas or P-Barons.
 
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