What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV-12: Cold Weather Flying

Geico266

Well Known Member
I made a few adjustments for cold weather, and thought you -12er guys would like to see them.

RV-12_in_snow__Large___Medium_.jpg

This little RV-12 pulled that F86 out of the snow bank! Well.... maybe not.

Test Conditions- Outside airtemp was 22-30F. Engine was run between 4800 to 5300 RPM to test different heat loads. 2500 MSL.

Oil Temps - I added a 2 1/2" (measured from center of hole down to edge of plate) oil cooler cover plate. It is held in place by the same #3 bolts that hold the cooler in place. Very simple. Now the temps are around 195 - 210F

RV-12_Oil_Cover.jpg



Cabin Heat - I added a simple 7 1/2' x 5 1/2" .020 plate to the radiator that you can put in without removing the lower cowling. Simply slip it in between the gasket and the radiator flange. The plate has a 90 bend in it so it cannot slip down any farther. This covers up the top 1/4 of the radiator. Very simple and it works! CHTs are 185- 202F Cabin heat is warm!

Here is the radiator cover prototype. While it did not move in flight, Marty & I thought it would be best to add flanges on the top & sides on the "production model" to keep it from moving.

Rv-12_Radiator_cover3.jpg


RV-12_Radiator_cover.jpg


RV-12_Radiator_3.jpg


Here are the completed parts.

RV-12_Winter_Kit.jpg


Patent Pending ;)

Cabin Sealing - I noted in flight where air was leaking in around the canopy and added weather stripping until it stopped. Do this sparingly, as the weather stripping gets hard in the cold it becomes difficult to close and lock the canopy if you apply too much.

What else have you cold weather RV warriors been doing?

I love flying in cold weather with snow on the ground. No bugs, thick air, you can see wildlife 10 miles away against the snow. Yesterday, I was flying over my secret deer area and saw a heard of whitetails that I conservatively estimated at 250. I have never seen so many deer in one area. These are the "good old days".
 
Last edited:
Larry,

You mention how well the the cabin heat worked. How about the passenger side, especially their feet? Other than the CPU fans, I see no way to get heat over there without frying the pilots legs.

Art Pennanen
 
Larry,

You mention how well the the cabin heat worked. How about the passenger side, especially their feet? Other than the CPU fans, I see no way to get heat over there without frying the pilots legs.

Art Pennanen

Yea, you might have a problem if you are the passenger keeping your feet warm. I think the hope is the air flow is good enough to keep the temps uniform. I'll have to fly it from the right seat and see.
 
Please 'splain ......

Will someone please explain the theory of operation of these things? Are they to increase the heat or lessen it? Isn't there a heat control in the airplane?
 
Radiator Cover

Thanks Larry for sharing the information and the pictures. At what OAT do you see as a tipping point to use these?

Scott Lane
 
Thanks Larry for sharing the information and the pictures. At what OAT do you see as a tipping point to use these?

Scott Lane

I would think 15F with these mods would be tolerable, but I have not flown in that yet. I'll report when I do.
 
Will someone please explain the theory of operation of these things? Are they to increase the heat or lessen it? Isn't there a heat control in the airplane?

What we are doing is getting the oil temps up to normal operating temps, and getting the coolant temps up so the cabin heater works better. The cabin heat controller just opens and closes the door. Yes, you get some control of the temps with the control knob, but when the OAT is below 40F it's gonna get chilly. With some tweaking I'll be flying comfortably when the OAT is zero or less. :D

Without ................ Oil temps = 145F , CHT's 170F
With .................... Oil temps = 200F , CHT's 200F

It would have been nice to have the Rotax required coolant temperature gage installed during construction, but for what ever reason Vans left this out of the build specs. We can live with the CHT's temps for now, but a coolant temperature gage is required.
 
Last edited:
An oil thermostat is permenant fix to cool oil temps available to all RV's. It really hasn't caught on for Lycomings, but they certain could be used on them. Rotax engines has recommended these for years. I have installed them on a couple of planes with great success. The oil temps get to 180F and stay there winter or summer. No more baffels to mess with.

http://www.alamomotorsports.com/pmc/Cat_page14.html
 
Last edited:
An oil thermostat is permenant fix to cool oil temps available to all RV's. It really hasn't caught on for Lycomings, but they certain could be used on them. Rotax engines has recommended these for years. I have installed them on a couple of planes with great success. The oil temps get to 180F and stay there.

http://www.alamomotorsports.com/pmc/Cat_page14.html

I used the oil thermostat that Lockwood sells, on the 912, in my RANS. It worked like a charm. Easy to install, and brings the oil temps up to the normal operating range much quicker- no waiting in the runup area at the end of the runway. Steve
 
An oil thermostat is permenant fix to cool oil temps available to all RV's. It really hasn't caught on for Lycomings, but they certain could be used on them. Rotax engines has recommended these for years. I have installed them on a couple of planes with great success. The oil temps get to 180F and stay there winter or summer. No more baffels to mess with.

http://www.alamomotorsports.com/pmc/Cat_page14.html

I used the oil thermostat that Lockwood sells, on the 912, in my RANS. It worked like a charm. Easy to install, and brings the oil temps up to the normal operating range much quicker- no waiting in the runup area at the end of the runway. Steve

I tried one of these thermostats and didn't see a major improvement. It did help a little but I personally didn't feel that it was worth the complexity in the oil hose routing etc.
I am not aware of any Rotax documentation recommending their use, but I know they have been used for years (here in the states anyway)
 
Last edited:
Are you aware of the Rotax documentation requiring coolant temperature monitoring?

I stand corrected about the oil thermostat info...I now do remember seeing it previously. I think that is why I tried one of the thermostats. As I said already, it did help...just not as much as I had hoped for so I decided it wasn't worth the effort. Others might think it is....

I am not sure how that question applies to the subject of this thread?
I did not mean to imply that something shouldn't be done to regulate the oil and coolant temps, I was just mentioning that I hadn't had significant results from the use of an oil thermostat

There has been a lot of different documents that have addressed different issues related to coolant, oil, and the monitoring of their temperatures during engine operation.

Until more recently, the install documentation that came with a Rotax 912 specified that an airframe manufacturer was responsible for verifying that the coolant remained below the specified maximum temp in all expected flight conditions. After that the airplane was to be operated within the limits of the CHT indications. This has been teh requirement for 912 installation for many years. The RV-12 was designed to comply with this requirement. It is my understanding that Eric Tucker of Kodiak Research inspected the complete engine installation of N412RV at Sun & Fun this past spring. He made a couple of minor recommendations but said nothing about the requirement of a coolant temp gauge. Only after RV-12 N412RV received S-LSA approval have I seen any document saying that Rotax required monitoring of the coolant temp.
That is why an RV-12 kit has no coolant temp gauge as part of it's instrumentation.

When operating in extreme cold, an RV-12 owner will have to do something to regulate temperatures. N412RV has been operated with a cover plate blocking 50% of the oil cooler when OAT's on the ground are below about 40 F.
A block off plate covering about 30% of the cooler has been used when OAT's on the ground are below 60 F.
 
Last edited:
When operating in extreme cold, an RV-12 owner will have to do something to regulate temperatures. N412RV has been operated with a cover plate blocking 50% of the oil cooler when OAT's on the ground are below about 40 F.
A block off plate covering about 30% of the cooler has been used when OAT's on the ground are below 60 F.

It is good to see acknowledgment of the need to regulate temperatures for cold weather flying. Data points from the S-LSA are a good starting point. However, proper (and now Rotax required) engine instrumentation to accomplish these seasonal adjustments are obviously more critical than ever. It seems appropriate now to have Vans make some recommendations as to vendors or part numbers for adding coolant temps to the Dynon D180.

Scott, no one I know of is looking for a freebie, just guidance as to what to buy. Maybe now would be a good time to accomplish that.
 
Last edited:
However, proper (and now Rotax required) engine instrumentation to accomplish these seasonal adjustments are obviously more critical than ever. It seems appropriate now to have Vans make some recommendations as to vendors or part numbers for adding coolant temps to the Dynon D180.

Scott, no one I know of is looking for a freebie, just guidance as to what to buy. Maybe now would be a good time to accomplish that.

I could be wrong, but I don't think Rotax intended the coolant temp gauge to be available so you could regulate temps with changing seasonal conditions.

The only reason is to verify that the coolant does not reach a boiling point temp. That is why they say no temp gauge is required if evans waterless coolant is used. The problem with Evans is that it has a lower heat transfer coefficient (it will not transfer the heat from the engine to itself as efficiently, and it will not release the heat to the air through the heat exchanger (radiator) as efficiently.
As a result, if evans is chosen as a coolant, you will automatically have a coolant temp that is at least 20 or so deg F. higher than if 50/50 water/glycol based coolant is used (from the research I have done it would probably be even higher in hot climate temps).

I seem to remember you mentioning that you have flown (owned?) a number of other airplanes that had a 912 in them. I doubt that they had a coolant temp gauge, but if they did, it wasn't because Rotax required it. That requirement has only been added recently.

As for adding a temp gauge...once out of the 5 hour production test period a builder can add what ever he wants or thinks is needed. I don't think Van's has any plans to add the temp instrument just because Rotax changed the rules in the middle of the game so to speak, but you will have to contact someone in technical support to inquire about that.

Just a side note to this subject...there have been many Flight Designs CT's, and Storms, and Sport Cruzers, etc. that have been produced for quite a few years now, and as far as I know they do not have a coolant temp gauge (please correct me if I am wrong) I wonder if all of these airplanes will now be getting a coolant temp gauge installed?
 
Last edited:
My Jan 2007 build Flight Design CT came with a CHT but not a coolant temp gauge. I do not know of any CT's that have coolant temp gauges.
 
I seem to remember you mentioning that you have flown (owned?) a number of other airplanes that had a 912 in them. I doubt that they had a coolant temp gauge, but if they did, it wasn't because Rotax required it. That requirement has only been added recently.

Two Rans S-12S, one Rans S-12XL, one TL Sting 2000. All four had coolant temp gages, and three had coolant pressure gages. The coolant pressure gage was a bit over kill, but Rans had them.
 
Last edited:
This a very interesting thread. Especially for those of us in the frozen north. Please excuse my ignorance, but is the Dynon programmed to accept a coolant temp input and display the result? If so, why wouldn't it be a good thing to install with the engine kit? Is there a recommended sensor for the 912?
 
This a very interesting thread. Especially for those of us in the frozen north. Please excuse my ignorance, but is the Dynon programmed to accept a coolant temp input and display the result? If so, why wouldn't it be a good thing to install with the engine kit? Is there a recommended sensor for the 912?

Yes.
It is required.
Yes.

The Dynon installation manual addresses the installation of coolant temp & coolant pressure monitoring on Page 3-17, and 6-17. The instructions are a tad confusing to my laymen brain so I'm hoping a vendor has done the work and we can just order a Rotax coolant temp kit. Rather than have everyone "re-invent the wheel with "adapt a part" hardware" it would be nice to use standardized parts in a kit form.

Blocking off the coolant radiator to get more heat in the cabin without monitoring the coolant temp is like running LOP in a Lycoming by monitoring the CHT on one cylinder. JMHO.


Here is an interesting article on 912 coolant temps.
http://lists.topica.com/lists/ultralightnewsextra/read/message.html?sort=d&mid=812495605
 
Last edited:
Larry,

Thanks for the answers. IMHO that makes sense. I don't like the idea of making changes and not being able to see the result. In my climate, in New York's Adirondack Mountains, getting the maximum amount of heat (safely) is very important. If the Dynon will support it, it seems like a no brainer.

I'd like to read that article, but the link doesn't work.

John
 
Coolant temp

Grand rapids Tech.(GRT) sells a fitting that has a temp sensor and fits fits in the water line. I have had water temp display since day one in my Rans S7S.
 
I added a 2" strip of tape down the inboard side of the radiator, and added my top plate to block off the radiator about 50% and went flying this am. OAT's were 5F. Tomorrow is suppose to be -15F, I'm gonna fly to a breakfast and see how that works.

CHT's 200F
Oil Temps = 200F

Cabin was comfortable, with a few new drafts I found coming from the wing roots. I do not have the gap seal installed yet.


This is good to know that you can fly when it is zero F outside comfortably, for me anyway. Some of the best scenery and smooth air is in winter.
 
Last edited:
This am it was -7F. Went to a fly in breakfast and back, about an hour round trip. Very comfortable when you push the engine to 5500. The engine produces more heat and the cabin temps were comfortable with coveralls on.

CHT's 210
Oil Temp 210

The -12 is an all weather flyer! ;)
 
Hey Scott McD.

Do you know the oil hose I.D. on the 12 ? Thinking about an oil temp thermostat.

Thanks,

John Bender
 
Looks kinda like

Van's should come up with a kit that will standardize a water temp hook up to the Dynon. I certainly wouldn't mind paying for this add-on. Peace of mind is what the $s would buy. Hope that they will consider this seriously.

BTW, Larry - great picture - I don't know much about that 'white stuff' that's in the picture but it is beginning to look like I will learn - as I am being TAXED OUT of my home state (TAXYAFORNIA). Can't stand the political climate here anyway.:mad:
 
E. D.,

Agree with you on the sensor. Be glad to pay for it.

Don't move to New York, we're in worse shape!

JP
 
Like to revive this subject...has Van's kitted anything to address this issue?

Ditto on California....consider Prescott, AZ; weather much like Redding, CA
 
Florida

Come to Florida, where the standard RV-12 heater is more than adequate, on the rare day that heat is needed. I am a refugee from CA (30 years in Bay Area, based at KOAK). FL has no income tax and only a 6% sales tax (tourists pay the bills for us). In addition to great WX, the state has dozens of residential airparks where $350K will buy a nice house with a 50' X 50' hangar.
 
Damm...

Keeping the -12 warm in flight is just one of our challenges in winter. Wearing cloth gloves while removing the fuel cap is NOT recommended. Slipped out of my hands on the weekend and added an ugly dent on the trailing edge of my flapperon. Did I say winter sucks BTW.

2n6rdvo.jpg
 
Keeping the -12 warm in flight is just one of our challenges in winter. Wearing cloth gloves while removing the fuel cap is NOT recommended. Slipped out of my hands on the weekend and added an ugly dent on the trailing edge of my flapperon. Did I say winter sucks BTW.

2n6rdvo.jpg

Sorry to hear/see this pal.
 
I slid a baffle down in front of the radiator this last Australian winter and it worked well. I started covering about 4" and then upped it to 6". Next year I'll make even a bit bigger. Flew some circuits a couple of weeks ago with temps just over 80 F. Forgot I had it in still but all in the green. Did an hour and half cross country last week at 90F as a test - still ok but had to keep speed up in climbs, at least until I reached cooler air. There's plenty of cooling capacity in that radiator!

Jack
 
Don't feel bad, Brent. I managed to push my plane back into the hangar and into my car crunching the left AST. It only cost about $75 to get the parts from Vans to build another, but the paint shop charged $300 to paint it. I'd trade for your dent any day!

Rich
 
Has anyone in the Northwest installed the oil and radiator plates detailed in GEICO266's 12-12-2009 post in this thread? I am tempted, it was pretty chilly flying this weekend
 
Has anyone in the Northwest installed the oil and radiator plates detailed in GEICO266's 12-12-2009 post in this thread? I am tempted, it was pretty chilly flying this weekend
Yep, cover 1/3 of the oil radiator and 1/2 of the water radiator and fly. Adjust as necessary. Did that for a couple of winters, then.... installed the oil thermostat and the "Bender baffle". A perfect solution.
 
Back
Top