Air Conditioning, Regrets, Woulda-Coulda-Shoulda

Hey all,
My name is Tim and I'm operating out of KCOI here in Florida. I've had 2 dream airplanes - an Aventura II amphibious which I now fly and an RV10.

Through incredible good luck and amazing friends at the airport, I was presented an offer I absolutely could not refuse.

I took over a project that, at his estimation, was about 65% complete. Slow build everything, and his work is immaculate - and he's also an amazing guy who shares many of my hobbies. But time because a resource he just couldn't get more of, so he had to let the project go. So now it's mine and I couldn't be happier.

And if I'm being honest, that happiness comes with a ton of intimidation. I've never ever taken on something like this before but I have an amazing field of experts here at my local EAA that I can call upon if I get stuck and a great group of friends who are very interested in participating. And while I know I will always be the only one I can TRULY count on to do the day in/day out work, it's nice to have a group of folks who will come by even if it's for an hour or so to see how things are going.

I still have to order the finishing kit - I'm sad to see Vans is quoting an 18 month delivery on those but heck, maybe I'll need all of those 18 months before I'm ready for it.

At any rate, I'm wondering for those of you who have already been there and done it if you have any regrets on what you did a certain way. Or rather if you have things that worked out exceptionally well for you if you wouldn't mind sharing.

For example, I've seen a lot about Air Conditioning. For me, living here in Florida, it would seem to be a must-have. I'd love to hear from folks who installed it but later regretted it. I know there's a bunch who say they don't want/need it but count me among the folks who don't want a sweaty seat and back the entire trip - and yes I know it's colder at altitude .

This forum has been a Godsend for me and I can't believe how blessed I am to even have the opportunity to become one of the folks who built their own RV. Thanks again for any advice you might have for someone at my stage in the build process.

I'm putting A/C in mine for sure. Like you I've researched high and low for opinions. Bottom line for me, my wife won't get in unless it has A/C... She's not spoiled (well maybe a little) but a little claustrophobic and the cool air helps. Seem those that have it LOVE it, those that don't have don't want it. You used to be able to buy an automobile without A/C. Those days are gone, not sure you can even get a car without A/C any longer. Eventually, the same will likely be true for our aircraft.

In my non-AC certified plane, the discomfort seems to be on the ground and can be considerable. I can usually climb high enough to cool off, though. In fact I often need to.

AC would definitely be a major plus.

You know the downsides, cost, weight, power loss, complexity and perhaps increased maintenance. None of these are trivial.

I thought about trying to home-build a car system into my RV-3B, but the plane is just too darn small. Sigh.

Dave

It’s simple, what do you want, and maybe your significant other. Do you want to trade off approximate 60 lbs useful for an AC, or use that weight to carry stuff, passengers, etc. Do you want to spend the money for the AC equipment, and require maintenance, or put those funds toward something else.

But, but

Once, a long time ago, I was in a Piper dealer maintenance school bashing on people who had to have air conditioning in airplanes. This was in the early days of Piper offering it on Warriors and Archers. Somebody in the class mentioned that it sure made it easier to sell flight instruction in Arizona. And now I get it. I remember the bad old days of just sweating in my cars with just the ol’ 470 air conditioner. Yeah, those days are over. I wish it was easy and cheap to cool our RV-6.

Happy Wife = Happy Life

In 8 years and over 1000hrs of flying our RV-10, I would say that adding A/C was one of the best upgrades we did.
My wife flies more with me because of the upgrade and to be honest I enjoy the A/C and use it a lot even in the middle of winter in conjunction with the heaters to defrost all the windows.

Sitting on the ground at YBDV, Birdsville, Central Australia. OAT is 35C (95 F) and the cabin temp at the pilot station is 23.5C (74F)


and even cooler at the rear pax station,



Installing another Airflow System A/C in a brand-new flying RV-10 a couple of months ago and the total installed weight was 21kg (46.2 lbs)
(This was the net weight increase that include removing the Odyssey 925 and fitting a EarthX 900 Battery)


Test data from install,
T1 and T2 are L/H and R/H of Condensor Intake
T3 and T4 are Evap output at Pilot Station and Rear Bulkhead,

Another thing to keep in mind is that it will shift your cg aft. It won't be a factor with just you and the wife, and you will probably still be good with four people, but trying to go somewhere with 4 people and bags may be an issue. In my case, 4 people and bags meant that I had to keep the fuel tanks at least half full to keep the cg in range, limiting my flight range. Most of the time, this doesn't limit me, but it is something to keep in mind.

I've had it here in AZ for 9 years and 800 hours and zero regrets. My system, Airflow systems, is essentially CG neutral with the compressor up front, condenser mid, and blower etc aft.
We use the system way more than we expected. Typical trip to OSH, the blower is on 100% of the time and compressor on 80%.
One of the biggest benefits isn't actually temperature, it's humidity. It's amazing how much water is removed from ambient air and dumped overboard. That is a huge benefit not only to occupant comfort, but also to the structure, avionics and interior materials and in preventing musty old airplane odors. Speaking of odors, I've never had a passenger get sick in the a/c equipped 10 unlike other aircraft I've owned.

This

togaflyer said:

It’s simple, what do you want, and maybe your significant other. Do you want to trade off approximate 60 lbs useful for an AC, or use that weight to carry stuff, passengers, etc. Do you want to spend the money for the AC equipment, and require maintenance, or put those funds toward something else.

Click to expand...

I agree. This.

Wow that's a fantastic writeup with some great real-world data - thank you! I would happily trade 46lbs for that sort of comfort! Heck, maybe I'll lose 20lbs and split the difference

Dustyone said:

In 8 years and over 1000hrs of flying our RV-10, I would say that adding A/C was one of the best upgrades we did.
My wife flies more with me because of the upgrade and to be honest I enjoy the A/C and use it a lot even in the middle of winter in conjunction with the heaters to defrost all the windows.

Sitting on the ground at YBDV, Birdsville, Central Australia. OAT is 35C (95 F) and the cabin temp at the pilot station is 23.5C (74F)

and even cooler at the rear pax station,

Installing another Airflow System A/C in a brand-new flying RV-10 a couple of months ago and the total installed weight was 21kg (46.2 lbs)
(This was the net weight increase that include removing the Odyssey 925 and fitting a EarthX 900 Battery)

Test data from install,
T1 and T2 are L/H and R/H of Condensor Intake
T3 and T4 are Evap output at Pilot Station and Rear Bulkhead,

Click to expand...

Steve D. said:

Another thing to keep in mind is that it will shift your cg aft. It won't be a factor with just you and the wife, and you will probably still be good with four people, but trying to go somewhere with 4 people and bags may be an issue. In my case, 4 people and bags meant that I had to keep the fuel tanks at least half full to keep the cg in range, limiting my flight range. Most of the time, this doesn't limit me, but it is something to keep in mind.

Click to expand...

Great call Steve, thank you. Perhaps in this case an 'old fashioned' aluminum prop might be the way to go to put some productive weight up front...

You’ve got to decide what’s more important for you— comfort on the ground (you really won’t need A/C in the air unless you plan to motor around at 3K or less a lot) or max useful load. I opted for useful load and have zero regrets. That said there are days I wish I had A/C. My wife did sew us up a couple of easy to remover slip-on seat covers that I can throw in the wash. So what I really need is a bigger plane so I can have my cake and eat it too.

I am curious,
We can talk weight and loss of power but put simple, what is your average speed loss when the compressor kicks on? 2-3 kts? Any?

Airflow's compressor draws power per the chart below, or about 4.7HP at 2300 engine RPM. So that equates to less than 1 kt speed reduction?

hgerhardt said:

Airflow's compressor draws power per the chart below, or about 4.7HP at 2300 engine RPM. So that equates to less than 1 kt speed reduction?
View attachment 38072

Click to expand...

I’d be more worried about the drag from the installation and its impact. Is that info available?

Airflow Systems Condenser Scoop

One part of my A/C System that has generated more conversations than the cold air that it produces is the Condenser Scoop mounted under the belly of the aircraft.

Some people love the look of the scoop (aka P-51 reference ),and others are amazed that it does not slow the aircraft down much.

The three other RV-10's that I fly with all have the same engine prop combos (stock IO-540 and Hatzell 2 blade )and once in cruise have similar speeds and fuel burn and my aircraft is the only one with A/C. Bill has often stated that there is a 0 to 1-2 knt penalty with the scoop and in my personal experience at LOP cruise with other RV-10's,it appears to be zero.Now I am sure that in a flat out max speed drag race there must be a difference but this is not how I fly.

I asked Bill at Airflow about this and received this reply that he was happy for me to share :

?Design considerations I used choosing to go with scoop;

My experience with certified aircraft air conditioning showed that many ADs had been issued because of Carbon Monoxide contamination for AC systems where condenser was positioned inside fuselage.
Mounting condenser outside of fuselage not a new idea, it has CG and maintenance benefits (access to tail cone).
What was new was Airflow Systems design efforts, with the help of wind tunnel, to create the absolute lowest drag, lowest weight, lowest electrical draw condenser installation.
Starting with a scoop that was certified for a Cessna AC system we were able to reduce drag by more than 50% through multiple design iterations where maintaining attached flow seen in the photos was the goal.

AC systems without scoops also have drag because no matter what system you have, you have to force air through the condenser and exit that air overboard. *that requires inlet holes and outlet holes which are never drag free.

*Note how the tufts are attached all the way back on the scoop indicating very little separation.* We found that we did not need as many louvres as shown in the photo and that reduced drag as well

I attended the San Diego State University where the wind tunnel is located in the early 70s (finished at another university) and never knew the wind tunnel was there until years later when I read a book by one of the professors on staff there. It was built in the early 60s using a cut down P-51 prop and a very big electric motor. *i wonder if my career would have been different had I known it was there, I really enjoyed the testing process and being able to develop new parts based on repeatable, reliable data.?





https://vansairforce.net/community/showpost.php?p=1192873&postcount=19

So I'll go ahead and nominate myself for Dunce of the week... When I asked my question about regrets and AC, etc I just COULD NOT believe this topic hadn't been talked about in this model specific forum.

And then I scrolled down and saw I was limiting my view to posts made in the last 2 weeks.

Good Lord it's a good thing I'm not allowed to do anything important like fly airplanes.

hey wait...

Anyway, sorry for the dupe thread, I know it's a cardinal sin. I guess I should bring up something that hasn't been talked about.

What's everyone's thoughts on priming? (JOKING!!)