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Cons of Air Conditioning in a RV10

ten4teg

Well Known Member
Was looking for some feedback on the negatives of having AC in a RV10. What does it take away from useful load and performance, etc. Thanks
 
I don't have AC, but that's because the biggest con I see is if it's so hot you need AC, then you are going to have a hard time keeping the engine temps under control, and the AC will just make that worse.

-Marc
 
My brother in law has a 421 (AC of course) and I fly in it all the time.

AC is “nice” but not needed in my opinion. So I went w/o when looking for a 10.

But consider where you fly in-out. Mostly Non-towered airports for me so not on the ground long but I could see longer ground and taxi times at Towered airports,
 
You need to evaluate what is best for your mission. So what do you, and those that will be flying with you, need. More useful load is important to us along with less complexities. We had a Saratoga with AC and didn’t use it much. Some people don’t do well in the heat, don’t like sweating, or the spouse who flys with you wants the comfort if they are going to fly. For us, we use our airplane like a SUV. We load it with camping gear, have hauled a massive amount of stuff to the Fl Keys after Irma, etc. 50-70 pounds of weight loss would mean that much more of “stuff” we would not be able to haul. And you can pack a lot of stuff in a -10. My wife cracks the door while taxi etc. once you climb past a few thousand feet, AC is not needed. This is based on flying both down in Florida, and over the desert in California. But I have friends that would not fly without AC.
 
Luxury comes at a price. Condenser, evaporator, plenum, fan, lines, electrical, and the install.

Cost?
 
I used to fly a friends Cirrus SR22, and while it was “classy” to drive around on the ground with the AC going, I wouldn’t want it in my plane. Cons are weight, cost, complexity..perhaps slight power loss.. I find that going high enough that you don’t need the AC.. typically only needed on the ground taxing, but for a fraction of the cost, you could do one of those “Ice Cooler fan” things that blow cool air in the cabin. And you can remove it the 10 months or so that you don’t need to carry the weight. If I was shopping for a 10, I personally would look for one without AC.
 
I've had AC in my -6 for 4 years now. I turn it on whenever OAT is above 65F. It's fantastic, and I'll never have another airplane without it. Another huge benefit of AC is the humidity reduction.

I suppose it all comes down to how much you can tolerate heat and humidity. I grew up in SoCal and if it's warmer than 75F, it's a hot day.
 
Plus 1 on the humidity reduction. It is amazing to see the puddle on the ramp under the drain upon shutdown. A lot of that water is otherwise going to be soaked up into the interior materials, floor cavities and avionics which after a few years can create corrosion and that stale musty old airplane smell we've all noticed in spam cans.
Power loss is immeasurable. My airplane has speed and fuel burn numbers as good as any other with similar power plant. Weight is less than the bump to 2800 that most builders designate.
I would never put it into a sport airplane, but IMO, a multi-six figure luxury cross country cruiser that is certain to entertain guests is naked without.
 
A/C in the right places

I was admiring another Beautiful RV10 on the ramp last week and noticed a compressor peeking out from the Cowl Air Inlets. I remarked that must be Air Conditioning, how do you like it? The owner opened the door and pointed out the beautiful micro webbing seats with plumbing for A/C right into them. Literally the seats are being inflated with cold air. He says "I like it OK, but my Lady Loves it" Now my thoughts turned to the direction of air flow: Vents in the overhead console will help cool the minds and keep the Makeup on a Lady's face and then ventilated seats will keep all other important parts cool and pleasant as well! Now there are TWO MORE GOOD REASONS FOR A/C. :cool:
 
Weight aside, I note many of the installations with an engine driven compressor and a stock cowl have a large hole in the Vans front baffling, for the belt. That's a large loss of deltaP, thus engine cooling capacity. Avoiding the Big Leak usually drives a cowling decision toward something with outboard intake ducts and a plenum lid.
 
I have an RV10, live in the northeast, did not install AC and kick myself in the a$$ every time i fly during the summer. It’s uncomfortable on the ground when temps are above 80 - I will not taxi with my doors open. Probably need AC through 6,000 feet and then its cool enough to not need it.
 
I chose no air in the 10 for the same reasons as others. I find it manageable. However, I understand the situation is not the same for everyone. I flew to TX last summer. WOW was it hot. The only time that I questioned my decision, while we literally roasted during taxi. It was almost a safety issue, as I contemplated skipping things like a checklist it was so rough. Probably wouldn't have been as bad if it wasn't dead calm winds. 3K under the bravo was hot, but tolerable.

I have never had issues in the 6, but the 10 has airflow problems on the ground if you are not willing to open the doors more than a couple inches.

Larry
 
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Everyone has to do their own calculus based upon their situation. I live on the Gulf Coast of Central Florida. Heat and humidity are present almost year round. However I opted to not install A/C as I didn’t want the useful load hit and was unwilling to adjust my max gross to mitigate. Cost was also a factor. Also I’ve never flown a plane with A/C so I don’t miss it since I‘ve never had it.

Yes it can definitely suck on the ground, especially waiting for an IFR release, but once airborne it’s a non-issue IMO. My wife also sewed some slip on seat covers for the front seats that are easily removable for washing. After years of being a “door is never open when the prop is turning” advocate, I’ve just recently changed my mind and now will taxi with the doors cracked no more than 6” and secured by hand or strap.
 
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I don't have an RV-10, and my airplane doesn't need A/C. I have thought about getting one of these for my camper van though:

https://www.zerobreeze.com/

I wonder if it could be made to work if you could vent the hot air out to a low pressure area on the exterior. The nice thing is that you could easily remove it during the cooler part of the year. Also, if you don't have enough electrical capacity, you could run it on the optional battery.
 
For all those that say no, do you have or ever fly with your wife or girlfriend? :D

Wouldn't ever consider it, when I have the wife onboard (which is quite often) she tends to shed clothes :D
 
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I don't have an RV-10, and my airplane doesn't need A/C. I have thought about getting one of these for my camper van though:

https://www.zerobreeze.com/

I wonder if it could be made to work if you could vent the hot air out to a low pressure area on the exterior. The nice thing is that you could easily remove it during the cooler part of the year. Also, if you don't have enough electrical capacity, you could run it on the optional battery.

ACs follow fixed physical laws. Based on outside temp and wanted BTU you can calculate how many kWatts of power you need to achieve that.
The other way around if you have the power consumption given by the AC manufacturer, you can calculate how many max BTUs the unit can make at a certain outside temperature. When I run the numbers for an RV-10, a good sized AC with 20,000 BTU will consume at least some 6 kW of power.
These battery or cigarette lighter powered zero breeze units have no chance to act as a decent AC.
 
ACs follow fixed physical laws. Based on outside temp and wanted BTU you can calculate how many kWatts of power you need to achieve that.
The other way around if you have the power consumption given by the AC manufacturer, you can calculate how many max BTUs the unit can make at a certain outside temperature. When I run the numbers for an RV-10, a good sized AC with 20,000 BTU will consume at least some 6 kW of power.
These battery or cigarette lighter powered zero breeze units have no chance to act as a decent AC.

No on the red text, but the rest of your comments are correct. Occasionally the assumption is made that compressors require the same amount of power to operate as the heat energy contained within the refrigerant being pumped by said compressor. This is an incorrect assumption. The refrigerant carries much more heat, or energy, than the compressor consumes. Here are the curves from Sanden compressors (just an example; AFS uses a different compressor): http://www.sanden.com.sg/opencms/ex...n/images/pdf/Performance_Curves-xWebsitex.pdf

Read the attached explanation which has the compressor curves from the Airflow system. Note that at 2600 engine rpm, the compressor can pump up to 19,500 BTUh (5.7 kW) but requires only 5.2 HP (3.9 kW) to operate. A keen eye will also see that AFS's compressor is not as efficient as the Sandens.
 

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No on the red text, but the rest of your comments are correct. Occasionally the assumption is made that compressors require the same amount of power to operate as the heat energy contained within the refrigerant being pumped by said compressor. This is an incorrect assumption. The refrigerant carries much more heat, or energy, than the compressor consumes. Here are the curves from Sanden compressors (just an example; AFS uses a different compressor): http://www.sanden.com.sg/opencms/ex...n/images/pdf/Performance_Curves-xWebsitex.pdf

Read the attached explanation which has the compressor curves from the Airflow system. Note that at 2600 engine rpm, the compressor can pump up to 19,500 BTUh (5.7 kW) but requires only 5.2 HP (3.9 kW) to operate. A keen eye will also see that AFS's compressor is not as efficient as the Sandens.
I do use the correct physical calculations, see the enthalpy diagram, but I recalled the wrong unit, it needs roughly 6 hp not 6 kw, the diagram you had says 5.2 hp, same thing, probably they assumed a different outside temp. The hotter it is outside the less BTU you make with same hp effort on the compressor.
 

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To answer your question. Weight, cost, and complexity.

Having said that. I now have almost 1800 hrs on the 10 and if building again would definitely install an a/c.

I went the 24v electrical system route and flush mount air transitions with condenser in the tail. Speed is 177-180knots on 12.5 gph around 10k ft. Can take off hot engine on a 100 deg day and climb fully loaded with cyls at 400-410f at 500 to 700 ft/m. Around 430f if you push it 1000 fpm when it's that hot but that's not often. Normally see 380 CHT in the climb.

I'm happy like it is
 
I suppose one "con" of installing air conditioning is... once you fly with air conditioning you won't be able to revert back to flying without it! At least in the TX summer :)
 
Can take off hot engine on a 100 deg day and climb fully loaded with cyls at 400-410f at 500 to 700 ft/m. Around 430f if you push it 1000 fpm when it's that hot but that's not often. Normally see 380 CHT in the climb.

I'm happy like it is

What's the oil temp on that 100 degree day climbing that fast? The -10 divides the cooling air on the left side with Cyl #6 and the oil cooler.

-Marc
 
ACs follow fixed physical laws. Based on outside temp and wanted BTU you can calculate how many kWatts of power you need to achieve that.
The other way around if you have the power consumption given by the AC manufacturer, you can calculate how many max BTUs the unit can make at a certain outside temperature. When I run the numbers for an RV-10, a good sized AC with 20,000 BTU will consume at least some 6 kW of power.
These battery or cigarette lighter powered zero breeze units have no chance to act as a decent AC.

Thanks Martin. I guess I should have clarified what I was suggesting. Engine driven systems in cars and airplanes are designed to bring the complete volume of air down to a comfortable level even in fairly extreme temperatures. They are kind of the benchmark for comfort.

The portable system I referenced would be more comparable to the ice chest type systems. Rather than completely cooling the cabin, they can provide some welcome relief by directing cool air directly at the occupants (probably 2 people max). As you mention, the cooling output is a fraction of the engine driven systems. Of course based on what this unit is, you have to have realistic expectations. Everything is a trade off.

Also, just to clarify, this style of unit was not designed by the manufacturer to be directly powered through a cigarette lighter. Users have measured power consumption anywhere from 140 to 165 watts on the higher settings. It is powered by the supplied 24V battery packs, or some users have wired up their own 12V to 24V DC/DC converters to run direct to vehicle power with adequately sized wire. Here are some various specs I was able to find:

Cooling output: 2300 btu
Unit weight: 16.5 lb
Weight for one battery: 12 lb
battery charge time: 5 hrs
Run time on high setting (per battery): 3.5 hrs

I see some possible advantages:

- Not cheap, but reasonable upfront cost
- Removable when not in use to save weight
- Ability to reduce temp a little before engine start
- No need to haul ice, and battery is ready to run anytime
- Charge in hotel
- Multiple batteries can extend run time


Having said all that, I think the manufacturers intentionally avoid hard specs on their systems because they don't compare favorably to conventional systems. Consumers often don't apply simple logic, and expect that when they say "portable air conditioning", it will somehow miraculously replicate the capabilities of larger systems. I put a lot more stock in the experiences of actual user's reviews. Also, keep in mind that some reviewers may have a vested interest. Buyer beware. Anyway, not for everyone (or maybe anyone), but thought I'd throw it out there.
 
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Thanks Martin. I guess I should have clarified what I was suggesting. Engine driven systems in cars and airplanes are designed to bring the complete volume of air down to a comfortable level even in fairly extreme temperatures. They are kind of the benchmark for comfort.

The portable system I referenced would be more comparable to the ice chest type systems. Rather than completely cooling the cabin, they can provide some welcome relief by directing cool air directly at the occupants (probably 2 people max). As you mention, the cooling output is a fraction of the engine driven systems. Of course based on what this unit is, you have to have realistic expectations. Everything is a trade off.

Also, just to clarify, this style of unit was not designed by the manufacturer to be directly powered through a cigarette lighter. Users have measured power consumption anywhere from 140 to 165 watts on the higher settings. It is powered by the supplied 24V battery packs, or some users have wired up their own 12V to 24V DC/DC converters to run direct to vehicle power with adequately sized wire. Here are some various specs I was able to find:

Cooling output: 2300 btu
Unit weight: 16.5 lb
Weight for one battery: 12 lb
battery charge time: 5 hrs
Run time on high setting (per battery): 3.5 hrs

I see some possible advantages:

- Not cheap, but reasonable upfront cost
- Removable when not in use to save weight
- Ability to reduce temp a little before engine start
- No need to haul ice, and battery is ready to run anytime
- Charge in hotel
- Multiple batteries can extend run time


Having said all that, I think the manufacturers intentionally avoid hard specs on their systems because they don't compare favorably to conventional systems. Consumers often don't apply simple logic, and expect that when they say "portable air conditioning", it will somehow miraculously replicate the capabilities of larger systems. I put a lot more stock in the experiences of actual user's reviews. Also, keep in mind that some reviewers may have a vested interest. Buyer beware. Anyway, not for everyone (or maybe anyone), but thought I'd throw it out there.

I’ll put it this way.
I had a zerobreeze unit in my last RV10. The one I’m building now has a airflow systems A/C.
 
I’ll put it this way.
I had a zerobreeze unit in my last RV10. The one I’m building now has a airflow systems A/C.

Good to know there is some real world experience out there. Hadn't heard of anyone trying it yet in an RV. Was it the model 1 or model 2? The new model increased voltage from 12V to 24V.
 
Good to know it's been tried. Can't argue with experience.

There is a new product just coming to market - EcoFlow Wave. Its a 4000 BTU unit which is a little more than the ZeroBreeze... i'd love to give it a try, but their return policy looks like they might give me a hard time if i do use it and try to return it. I can't justify taking the risk of dropping $1800 only to find I'm stuck with something that won't work well. (its pretty heavy too)
 
All Depends.....

It does all depend on your mission and where you live. If you live in the south and don't plan on 4 people at higher density altitudes then it is perfect. The change is CG can be a bigger factor than the weight in my opinion. Not sure what the CG change is on most systems.

It would be awesome to have but we live in dry Utah and even when it is 100+ outside it is not bad for us. Once you climb to 11,500 it is cool and nice. It has never been anything me or my wife has ever thought about putting in.

I have been flying my RV-10 for 15 years now and we need it as light as possible so we can explore Idaho with the four of us and all the camping gear. I am still wanting to find ways to strip out weight. The best thing I ever did was LiFiPO4 batteries for this cause.

When your sitting on a grass strip looking at 30' trees at the end of the runway at 7,000+DA in a canyon with your family on board and camping gear, you will be glad you don't have it.
But that same scenario with just two on board would be awesome with some A/C and Mozart playing while sipping your lattes to stay warm.
 
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