Cherokee 140 air conditioning.... Does it work?

N

noobJohn

Pre-takeoff checklist
Joined
Aug 12, 2013
Messages
489
Display Name
Display name:
John
I'm still in the dreaming/scheming stage of aircraft ownership.

I currently rent either a 172 or a Cherokee 140. I like various aspects of both but, for some reason I can't quite explain, the Cherokee is growing on me.

One issue... HEAT!!! There's definitely a baking aspect to the Cherokee when you're sitting on the ground and, even in the air, the good vents are down by your feet instead of up near your head, like on the 172. So I spy this airplane on controller :

http://www.controller.com/listingsd...ROKEE-140/1973-PIPER-CHEROKEE-140/1328863.htm

I realize A/C is a hit to an already low useful load but if I'm looking at this as a 2 person plus bags plane.

My question is... Does it work? Will it blast out cool air and leave you cool, calm, and collected while taxiing and flying at low altitudes in the summer?

Remember my main question.... DOES IT WORK?
 
:D I should probably give a little background. I had a 1969 Camero. It had A/C but.... even when it "worked" it was weak. Blower was weak, vents were small, black interior, large engine up front, overall you were better off rolling down the windows. I was wondering if the A/C in these old planes was of similar ability or if it would freeze you out like all modern cars will. :D

Henning said:
Yes..
Click to expand...
 
Assuming it's in good mechanical condition, they work.

Flew in a old Piper Saratoga in Africa once that had one. You turn it on after takeoff and it cools just fine.
 
I would suggest getting the Weight and Balance sheet on this plane and see what the useful load is after fuel. I would guess it will be Very Small.
 
When you charge it with R-12, because it will need to be charged almost certainly, insure you do the leak checks first, and do it in the morning when it's cool, with lots, and lots of air flow over the condensing coil. Prolly need to use a box fan and some kind of temp ductwork into the condensing unit intake.
 
Scott@KTYR said:
I would suggest getting the Weight and Balance sheet on this plane and see what the useful load is after fuel. I would guess it will be Very Small.
Click to expand...

Says in the add

"Additional Equipment:
Useful load 652
50 gallons total fuel"

So 352 pound payload.
 
docmirror said:
When you charge it with R-12, because it will need to be charged almost certainly, insure you do the leak checks first, and do it in the morning when it's cool, with lots, and lots of air flow over the condensing coil. Prolly need to use a box fan and some kind of temp ductwork into the condensing unit intake.
Click to expand...

If there is no fan on the condenser I can't imagine it will cool much on the ground.
 
bnt83 said:
If there is no fan on the condenser I can't imagine it will cool much on the ground.
Click to expand...

I don't know about a fan on the condenser, but I doubt it. Which is why I advised a lot of air flow during the charge process so that it will exchange well, and get the max freon into the system during the charging. Maybe I should have said 'external box fan' to be more precise? Something sitting on the ramp, on high with a plastic duct taped to the intake of the condenser port to sim in-flight air flow.
 
docmirror said:
I don't know about a fan on the condenser, but I doubt it. Which is why I advised a lot of air flow during the charge process so that it will exchange well, and get the max freon into the system during the charging. Maybe I should have said 'external box fan' to be more precise? Something sitting on the ramp, on high with a plastic duct taped to the intake of the condenser port to sim in-flight air flow.
Click to expand...

Easier to vacuum the system and charge by using the specified charge weight.
 
Henning said:
Easier to vacuum the system and charge by using the specified charge weight.
Click to expand...

Works for me, I doubt in 73 they used that method on an airplane but if you know the capacity that will provide a safe alternative. Of course, the actual gauge reading will provide better cooling because you can run it right up to the red line in high pressure which can't be done with the weight method. I mean, the plane, compressor, evap coil, expansion/orifice tube are all +40 years old, but whatev.
 
noobJohn said:
Prop puts out a pretty good breeze even at idle, right?
Click to expand...

You must understand that the prop wash doesn't necessarily make it through the condenser on the ground, or at a mass to be effective.

If the condenser has no fan or blower but relies on inflight slip stream airflow then it probably doesn't cool well on the ground.

Apparently it has been popular to remove them, making me question the effectiveness or (serviceability issues) even more:

http://www.piperforum.com/showthread.php?t=646
 
Last edited:
docmirror said:
Works for me, I doubt in 73 they used that method on an airplane but if you know the capacity that will provide a safe alternative. Of course, the actual gauge reading will provide better cooling because you can run it right up to the red line in high pressure which can't be done with the weight method. I mean, the plane, compressor, evap coil, expansion/orifice tube are all +40 years old, but whatev.
Click to expand...

Yeah, I wouldn't want to be red lining the pressure unless I was wanting to overhaul the system.
 
You best bet would to find one and go fly with the owner
 
Downside....unless you live someplace where you can run/need the AC year 'round or most of the year, during those times it's dead weight. This is why the portables (arctic air, b-kool, icebox, etc) have become popular. And then there's the maintenance, as mentioned here in a number of posts.

Factory AC was a marketing idea for little airplanes, and many were removed when the owners found out how impractical it was after the check cleared.
 
I owned a cherokee 140 for 18 years, originally equpped with AC. I never bothered to even check to see if it worked.

If it was so hot that I couldn't stand the few minutes on the ground waiting to take off, then the take off performance would be, ahem, anemic. In other words, I avoided flying at the particularly hot times anyway.

Other considerations: The AC system was, iirc, around 78 pounds of dead weight. I removed as much of it as I could (with appropriate log entries). My '74 cherokee 140 didn't have a lot of useful load, so I wanted to address that as much as possible.

Also, the cherokee AC system were apparently notorious for leaking - think about all the vibration that the seals and connections are subjected to.
 
murphey said:
Downside....unless you live someplace where you can run/need the AC year 'round or most of the year, during those times it's dead weight. This is why the portables (arctic air, b-kool, icebox, etc) have become popular. And then there's the maintenance, as mentioned here in a number of posts.

Factory AC was a marketing idea for little airplanes, and many were removed when the owners found out how impractical it was after the check cleared.
Click to expand...

Many more planes now are produced with factory A/C than were produced in the 90s and prior, so there must still be demand.
 
Consider one of the portable ice chest systems? Then you use it just when you need to, and leave it out when weight is a concern
 
Stryker1112 said:
Consider one of the portable ice chest systems? Then you use it just when you need to, and leave it out when weight is a concern
Click to expand...

They work nicely, but, they are not free of weight, in fact probably use up more useful load than a fixed A/C system does, plus they take up a decent chunk of cabin space. For most people on most flights, this is not a real issue, but if you are trying to fill the plane with people and luggage, you're not going to be able to take the AC when you will likely need it most.
 
bnt83 said:
How we stay cool on the ground.
Click to expand...

Nice, but here in San Antonio... your door is open so that the sweat can drip off you on to the ground versus the seat :) A/C is the only option here in Texas, IMO
 
I had already heard and considered most of the downsides, that's why my fundamental question was whether or not the system worked. If it worked well, all the downsides could be weighed against that awesome feeling of A/C on a hot day. If there's no upside then the choice is obvious.
 
noobJohn said:
I had already heard and considered most of the downsides, that's why my fundamental question was whether or not the system worked. If it worked well, all the downsides could be weighed against that awesome feeling of A/C on a hot day. If there's no upside then the choice is obvious.
Click to expand...

If the system functions properly it works. Most of the time in a plane with A/C I would only use it on the ground except one Ag plane that was equipped, it only tuned off for take off lol.
 
I have had several pressurized twins with AC, when they work, they are awesome! :yes: When they don't it sucks! :mad2:
It is a 40 year old system, expect to recharge it every year, I would guess May would be the right time and hope it lasts until October. It will have leaks, and it may not be worth the $$ to find and fix them all.:dunno:
Other than AC, I would not want a low wing airplane in the heat of Texas or even Georgia in the summers. My only regret about my 182 is the right side window doesn't open, the left side stays open until I get to cruise altitude, sometimes on short trips I never close it. :D Sure, it's noisy and the dog hair blows around a bit, but it makes a huge difference in the temps. :D
 
N747JB said:
I have had several pressurized twins with AC, when they work, they are awesome! :yes: When they don't it sucks! :mad2:
It is a 40 year old system, expect to recharge it every year, I would guess May would be the right time and hope it lasts until October. It will have leaks, and it may not be worth the $$ to find and fix them all.:dunno:
Other than AC, I would not want a low wing airplane in the heat of Texas or even Georgia in the summers. My only regret about my 182 is the right side window doesn't open, the left side stays open until I get to cruise altitude, sometimes on short trips I never close it. :D Sure, it's noisy and the dog hair blows around a bit, but it makes a huge difference in the temps. :D
Click to expand...


Cardinals don't do too bad there either. The little wedge window is hinged on the aft edge and is infinitely adjustable between open or closed via the little crank. You can rest your arm on the window frame and let the ram air from the open wedge blow right up the arm into a shirt sleeve.

 
If you live someplace like Florida it might be worth it. From my recollection (of about 35 years ago) it doesn't work particularly well, if at all, on the ground so you can forget about taxiing around in comfort. The condenser is a deployable platform on the belly and I can't remember if you're even supposed to have it out during take-off or not. The Cherokee blower is a pretty decent size but the overhead duct is kind of Mickey Mouse and prone to leaks.

The one I used to fly came from Florida but all my flying was in California and I never used it other than just messing around with it one time so it served mostly as dead weight. One summer afternoon myself and a buddy leaving
Lake Tahoe had to circle the lake four or five times to get high enough to come back home. But if you live in a very humid flatland area it would probably be useful.
 
bnt83 said:
You can rest your arm on the window frame and let the ram air from the open wedge blow right up the arm into a shirt sleeve.
Click to expand...

So you force your passengers to breathe in air that has done the once through your armpit hair? Nice.
 
We love ours! Works fine on the ground and even better in the air when needed. Does what it is supposed to do......keeps the wife happy and cools me off after getting the family loaded up.
 
Here's the page about the air conditioning system from the POH of the '77 Cherokee 140 I used to own. Note that it says at full throttle the system automatically disengages the compressor and retracts the scoop, so that takeoff and climb are not impaired. The throttle must be brought back "1/4 inch" to restart the AC.

The equipment list for this airplane says the optional air conditioning system weighs 67 pounds. :eek:
 

Attachments

  • Screen Shot 2014-07-31 at 10.13.13 PM.png
    Screen Shot 2014-07-31 at 10.13.13 PM.png
    153.9 KB · Views: 21
Cool! pun intended.

Dutch Norwood said:
We love ours! Works fine on the ground and even better in the air when needed. Does what it is supposed to do......keeps the wife happy and cools me off after getting the family loaded up.
Click to expand...
 
Cessna offered air conditioning (69.5 lb.) as an option in the 172N-P beginning in 1978. Those few so equipped could be identified by the scoop under the fuselage, as in the photo below.

cessna_172p_1981.jpg
 
Last edited:
My arrow has factory air conditioning. I have lowered the scoop a few times to see if it works. However, every time I have it filled with freon by mechanic, it is empty and non operational but the time I get there. My mechanic says it blew cold though when it worked. I would like to get it fixed but every one I talk to says I am better off leaving it inop. They obviously haven't flown with me from June throughgt September.
 
Your system has a leak and there is no point recharging it until that is fixed. There are different methods for detecting and locating the source of the leak, the easiest is probably to just empty it and with compressed air and a spray bottle of soapy water start looking. It's probably going to be an o-ring seal so to fix it you'll have to empty it and open the system anyway.

The second problem is getting Freon, which is R12. Difficult to obtain and expensive. Converting to readily available R134a refrigerant will mean a loss of efficiency because the system is not optimized for it. Changing the expansion valve and maybe installing a new parallel flow condenser can greatly improve those issues but honestly I doubt you can do that on a certificated installation. You may not even be legally able to put R134a in it to begin with.
 
Meh - fill it with propane. Close enough, it's just an Arrow. :lol::lol:

I keel myself sometimes.

Seriously, getting it pressurized with Nitrogen, and hunting down the leaks would be worth it. I would pay good money in TX to have an AC plane. I have the Beech evap "air conditioner" which works well in dry situations at altitude, but on the ground we have to rely on the ice box.

For most old R-12 systems I work on with vintage cars, one pernicious leak is the compressor front seal. You can usually check it by removing the clutch with a pulley puller. Pump the N2 into the system and use a spritz bottle with soap on the shaft of the comp. They leak because the seal dries out from disuse. If the system is used regularly, the seal stays in good shape, but once it sits for a while, they all leak. Also may have a leak in one of the o-rings of course but do check the front compressor shaft seal.
 
I used to rent an Archer III with air. Worked really well in Florida.
 
I had no idea that they put the AC on a 140 - but why not?

I have flown a couple of Archers with the AC, and it worked well, and I imagine it is exactly the same system (why would they have engineered a different one?), so in the smaller cabin of a 140, you should be able to hang meat.

If it is still charged with R12, not to worry - there is still a lot of it out there, if you want to stick with the factory fit; when it becomes too scarce, there are several drop-in replacement refrigerants which should work just fine.

If it leaks out the refrigerant, a good AC mechanic can track down all of the leaks and repair them properly. Main caveat on the Cherokee AC is that the belt is a puny little thing (you can see it in the nose picture), prone to fail. Figure on replacing it regularly. It would be worth it.

Oh, yeah - even if you aren't using the refrigeration (or it is inop), the forced-air ventilation is an additional benefit.
 
You must log in or register to reply here.
Back
Top