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Oil Temps???

Y

yankee-flyer

Well Known Member
made my first really hot day flight in 143WM this afternoon. Airport elevation 940 feet, OAT 88, Density Altitude 2800 ft.

I had to break off the climb (75 kts) at 3500 feet with oil temp at the top of the green arc.
Cruise alitude 3500 MSL, 5200 rpm, OAT 76deg.
EGTs: 1320/1270
CHTs: 197/192

Oil Temp 218-220, Oil pressure 54-58

I'm used to seeing oil temp more like 180-190, but at much cooler OAT. Are you guys in the great Southwast (or Florida) seeing oil temp like this? 700 rpm descent only dropped it to 207.

Thanks Wayen 120241
 
My experience is similar. Even in December, I couldn't keep the oil temp in the green all the way up on those test card trips to 10K. Had to lower the nose and climb at 85. 75 knot climbs probably work OK in Canada.

Jim in South Texas
RV12 N233TX
 
Welcome to RV12's...in Georgia, we've been having 95 degree temps of late and I can't fly about 2500' without having the temp gauge going nuts. I've got to cut my climb to 2500' and let it 'cool' a bit before I can continue my climb. I'd love to figure a way to get more cooling air to the engine.
Meade
N612RV
 
Seeing the same thing here with the OAT in the upper eighties/low 90s, the oil temperature is consistently 220 degF or higher. My CHTs at this same time are in the upper 190s. Tells me that some of air going to the radiator could be diverted to the oil cooler. Would some type of vane work to direct more of the airflow to the oil cooler? Any thoughts on a design?

I also asked a fellow what kind of oil temperature he was seeing in his CT2 on a hot day last week. He was seeing 200 degF, while I was seeing 224 degF in the RV-12. Anyone familiar with the oil cooler arrangement in the CT2? Why is the oil cooling so much better in the CT2?
 
Thanks, Guys

Well, at least I know I'm not alone! Marty, I don'y think closing down the duct to the water radiator would help much. It looks like the air has a straight path to the oil cooler, so the cooler itself is the choke point. I haven't looked to see if it's possible to put a diffuser behind the cooler to help pull air through, but both that and a larger cooler would mean even lower oil temps in the winter. Maybe we all should move to OR where apparently there are no temperature extremes.

Wayne
 
We had the same issue on 120186, the only thing that seemed to help was a lip installed at the bottom rear of the cowling where it hangs down below the fuselage. it was about 45 degrees and two inches long and extended the full width of that area.. It produces some suction in the cowling pulling more air across the oil cooler, at least that was the theory. It lowered the oil temp. about 7 degrees.

I have no idea why but some RV-12's just do not cool the oil as well as others, we have two here that do not have the problem.

Best regards,
Vern
 
Ambient temps

Summer temperatures in this part of Australia are often in the 95-105 deg range, so I'm interested in this too. We're on the coast at an elevation of only about 100', and a very cold day here would be 50-55 deg. As the tallest `mountain' within a couple of days flying time is less than 2,000', takeoff and high altitude performance is not an issue, but any tips on keeping the engine cool on a hot day will be welcome.
 
BigJohn said:
Hmmmm - I wonder how accurate the temperature probes are?
Click to expand...

Hi John,

The probes seem to be OK, there are three that are the same unit (Oil Temp, and both Cylinder Head Temp) and you can switch them around to be sure it is not a unit problem. I guess there could be some issue with the way the Oil Temp seat area is milled out but that would be a very hard to believe solution. It just seems that some aircraft do not cool as well as others. It may be some air flow issue caused by the way the front of the cowl is trimmed or some small issue in the way the cowl is fit, beats me in any case.

Best regards,
Vern
 
In addition to cooling air flow, ignition timing and fuel mixture can affect temperatures. Since airflow is pretty well pre-determined by Rotax and Vans, these may well be a place to look next.
I too have noticed reading the forums, SOME people have much more cooling problems than others.
 
MartySantic said:
Sure would be nice if someone could determine the reason(s).
Click to expand...

Hi Marty,

You hit the nail on the head!!!

I think it has to start with the aircraft manufacture (Van's) accepting that there is a problem and then accepting that it is their problem. They have just denied it exists so far. It would seem that if they would put some attention to the aircraft that have the issue and compare them to the ones that do not they may find out why as they are the designers and engineers behind the aircraft and the ones best equipped to resolve the issue. They also have the most to be gained through even more sales if they resolve the issue.

I sure miss having Van himself in control of Van's at least he could and would make things happen when it was in his interest to.

Best regards,
Vern
 
vernhendershott said:
Hi Marty,

You hit the nail on the head!!!

I think it has to start with the aircraft manufacture (Van's) accepting that there is a problem and then accepting that it is their problem. They have just denied it exists so far. It would seem that if they would put some attention to the aircraft that have the issue and compare them to the ones that do not they may find out why as they are the designers and engineers behind the aircraft and the ones best equipped to resolve the issue.
Click to expand...
The company prototypes/demonstrators have never exhibited overly high oil temps in hot OAT's. A trip was specifically made to Death Valley CA to perform hot weather operational testing of the prototype.

One factor that has to be kept in mind is that Van's Aircraft didn't assemble any RV-12's other than their own. There is no way to know if construction factors/errors are a cause for this on other RV-12's.

Another factor that has already been mentioned, in hot OAT conditions only some RV-12's have had higher than desirable temp. issues.

I know of at least two RV-12's that by the RV builders community are considered to be nicely built airplanes. They both have an error regarding proper trimming of the main cooling air inlet of the cowl, which likely has a detrimental effect on cooling (but apparently not an issue in the conditions they typically fly in). How many others may have this same error, or poorly fit radiator seals, or... etc.

I would be happy to take a look at any RV-12 that a builder is have higher than expected oil temps on, if they would bring it to me to look at.


One other factor that is confirmed to cause higher oil temps in hot weather is excessive propeller pitch. If the engine RPM is being lugged down during climb it will result in higher temps. If you can not turn up to very near 5000 RPM static on the ground at the airport elevations that you typically fly from(with near zero wind speed) then you are probably over pitched.
 
Vans Shoud Look Closer at this problem!

Lets look at this from another point of view. Yes the the two demonstrators which were built by experienced builders who had unlimited access to tech support don’t have any problems. I would say that at least 50% of the flying RV12s built have the high oil temps when flying in OATs of 85F or higher. If its so critical to build the cowl exactly correct then maybe the plans need to be clarified. If there is an exact prop setup that needs to be set to fix the problem then please send out a service advisory letter to all owners to let them know. Simply have Mitch Lock go to Spruce Creek and see Vern and compare notes with the 6 or so planes that are located there in one place to see what the differences are and how to fix the problem. Problem solved! How say thou! :confused:

PS With over 100 flying and 551 Kits ordered minus the 100 built maybe this would be a good time for Vans to take a survey of all owners and and ratchet up the customer service as this looks like a ground breaker in E-LSA aircraft. In other words Vans have taken the E-LSA to a level not seen before in the industry why not take customer service to a new level to. Vans Customer service is good but could it be better?
 
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Survey owners, what an idea, are you listening Vans? A nearly free source of feedback that should be worth lots more to you. You have one wonderful product in the 12, and this could only make it better! I suppose there is some hesitation to make changes to the original SLSA, but surely the FAA has it so you can make improvements without too much hassle.
What I have found that may surprise some, is that in speaking with other 12 owners, they seem very reluctant to put their overheating (fuel and oil) problems on this forum. Not sure just why, I suspect they feel they might have made some errors or something.
 
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DonFromTX said:
Survey owners, what an idea, are you listening Vans?
Click to expand...

If an RV-12 owner has read through his/her documentation, they would have found that there is already a specific process in place (required by the ASTM for S-LSA certification) for submitting a service difficulty or report a safety issue via Mail, Fax, or E-mail.
Look in Chapter 17 of the Maintenance Manual
 
rvbuilder2002 said:
I would be happy to take a look at any RV-12 that a builder is have higher than expected oil temps on, if they would bring it to me to look at.
Click to expand...

Sounds like a very good project for Oshkosh. There should be a number of RV-12s there and maybe, just maybe you can look at the RV-12s, ask the owner if he/she is experiencing high oil temperatures and try to collate the results. I have the stock seal and a good radiator seal, and my WOT static RPM is 5000 rpm. The cowl inlet is trimmed per the plans. My high oil temperatures (224 degF, 90 degF OAT) are observed at 5200 rpm in level flight. This temperature is after it has stabilized.

AND guys, PLEASE DO NOT beat on Scott, is he trying to help us. He has always tried to help and the beatings and rants are most likely the reason he has been absent from this forum. I for one, welcome his comments and it is my sincere hope, he will continue to visit this forum and comment more frequently.
 
MartySantic said:
Sounds like a very good project for Oshkosh.
Click to expand...

At Oshkosh, Scott's time will be pretty much dedicated to 8 Teenagers from the Teen Flight program, doing a forum, etc.

Even if I did do this it would still be a very small sampling of airplanes (if I could even connect with all of those that flew in).

So, why not use the process that is already in place? [That I described in my previous post]
Spread the word.... If you have any type of problem , use the system that is in place for informing Van's Aircraft. Doing it by e-mail with an attached download file from the D-180 would be even better but not required.
I don't mean to sound rude, but... If you think you have a problem, stop whining about it on line and send a report to Van's Aircraft about it.
 
Send the e-Mails!!

Just sent an e-mail per Chapter 17 in the Maint Manual.

RV-12 Safety Alert' (in subject line)
[email protected]

Will be awaiting a reply! URGE all to do the same.
 
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Didn't mean to open a can of worms

I'll send a report to Van's as soon as I bring the maintannance manual home from the hangar.

Wayne 120241
 
Gents,

Here is the answer to all your questions: Please view pics here

http://imageshack.us/g/571/cimg0109i.jpg/

I sported high oil temps since the begining of the ownership of my RV7A. Standard cruising temps between 208-220. Thought I had to live with it, but not anymore.

My oil temps now down and stable...183-186. And get this in my climb 193-197.

Dont be afraid....Just do it!!!!

Tango
 
And I am thinking this may be an excellent solution for the RV12 crowd as well. Would cool the gascolator as well.
 
Guys - Remember that Rotax officially and several Rotax service centers (e.g., Lockwood) endorse operating the 912S in the yellow during climb out if you use synthetic or semi-synthetic oil. There are lots of full synthetic oils for folks burning 100% mogas and at least one semi-synthetic (blended) option for 100LL users.

Check out the latest Rotax guidance on oil selection. Note that it recommends semi-synthetics for oil temps > 250F. IMHO, 250F seems really hot, and I've been told by Lockwood that getting the 912 to or beyond TBO includes keeping oil temps below 230F as much as possible.

Our CT will easily get to 230F (bottom of the yellow for us) at WOT and Vx, even on mild summer days (90F). Cruise climb and power reduction keep us in the green or bottom of the yellow for the most part. We are going to our 5 year annual next week and that involves hose replacement. We'll give the entire oil system a good going over a the same time.

TODR
 
Looks good! Is this aluminum sheet, cut for the fins and then bent them inside?
Hm, below 200F in climb... the next problem... how do you get the water out of the oil ;-) ?
 
MacPara said:
Looks good! Is this aluminum sheet, cut for the fins and then bent them inside?
Hm, below 200F in climb... the next problem... how do you get the water out of the oil ;-) ?
Click to expand...

I would think that any Hot Rod shop would have the die that makes the lovers like that as they were very popular in Hot Rods for years.

The oil temperature that we measure is at the coolest spot in the system so if you are at 200 F as it comes out of the oil cooler you are probably at 250 F as the oil returns to the tank and you will have no water problems if you fly at 200 F for more than 15 minutes regularly. Even 180 F will clear the water just fine for cold weather operations and it is a good target for the modifications that seem to be needed for operations with air temperatures below 40 F.

Best regards,
Vern
 
Dimensions?

Could you post the dimensions-- rough numbers would be fine. I assune that you put nutplates inside the fiberglass or did you put an aluminum frame inside for the nutplates. I like the idea of having these attached with screws-- in winter thay can be exchanged for solid plates to keep oil temps up.
For 12 builders, the right side would have to clear the duct for the water radiator.

THANKS!

Wayne 120241
 
They sure do, $22 each, heck of a deal!
2cnt4at.jpg
[/IMG]
 
DonFromTX

It did cool the gascolator and elec fuel pump. I have another thread on here I started concerning fuel pressure drops on taxi after a flight (vapor locking) and it fixed it. I'm telling you, it works...Its the bomb..unreal..

MacPara

Yes..alum sheet 25thousands thick. vernhendershott took the words right out of my mouth concerning your "water out of the oil" concern.

yankee-flyer

Dimension is 8" x 10" outside to outside. Yes I did use an aluminum frame on the insde, but mine is riveted permanantly in place not screwed. I do have intentions of making a cover for the winter months if my temps end up needing it.

Paris12Man

Mine go inward and upward and point toward the firewall.

TO ALL

Whoever is listening and sporting high oil temps and tired of fighting it and worrying about it everytime you fly should make this your next project..You'll sleep better every night for sure...Bottom line it works like a champ, so stop the worries and Just Do It!!!!
 
Most interesting on which way to point them. I would expect to have the louver opening to the rear, with the bulge downward for best airflow, and provide a scavenger effect as well as a path for cowling pressure to escape.
 
Unintended consequences?

The carburetor air intakes/filters are located inside the cowling. If you add louvers that suck air out of the cowling wouldn't that be lowering the air pressure inside? Isn't it possible even a sleight change in pressure and temperature of the intake air could affect engine mixture, performance, etc.?

I don't know that I would want to proceed with this mod until/unless Van's engineering people approve it. Then again, I am just a first time builder, not accustomed to doing my own engineering by trial and error. Quite possibly more experienced experimenters would have no qualms about just installing louvers and flying.

Not trying to start an argument, just expressing my (admittedly conservative) thoughts.
 
Valid points John, those and others need to be looked at of course. The carb effects should be mostly good, getting cooler air to the intakes is a good thing, they don't really depend on pressurized air. The problem is heat, and more airflow will remove more heat, no question. If one were to put temp probes around the engine compartment, I think we would see that the air gets progressively hotter on the way to the exit at the bottom of the cowling (down where the gascolator is located). This in turn might require things like an oil thermostat to keep the oil temp UP.
I doubt that Vans would ever offer an opinion on the louver installation, they would have to do their own testing, and so far they don't seem to believe there is a problem except with variances in construction, and they may well be correct there. Sure won't hurt to ask them though.
After all, this is what Experimental is all about I think, and we have one experimenter who has tried it, reported on it, and has had wonderful results..
 
Guys,

Just so you know, though I decided on my own to do this, van's does provide louvers for there RV10 to there customers and they point inward and upward and towards the firewall. As verified by Joe at Van's who sent me a pdf with the configuration. He also suggested that I could buy those very louvers to install on my craft.....all is good here....and it is the answer. Dont overthink this...For those who are searching for results in lowering there high oil temps its the fix!

Tango
 
taverroi said:
Guys,

Just so you know, though I decided on my own to do this, van's does provide louvers for there RV10 to there customers and they point inward and upward and towards the firewall. As verified by Joe at Van's who sent me a pdf with the configuration. He also suggested that I could buy those very louvers to install on my craft.....all is good here....and it is the answer. Dont overthink this...For those who are searching for results in lowering there high oil temps its the fix!

Tango
Click to expand...

Tango - Is your "craft" an RV-12, or another Rotax powered airplane that draws its carburetor intake air from inside the cowling?
 
No sir, dont have a rotax. I run an IO-360 M1B fuel injected engine. Please dont be affended by me being dogmatic about the results of the louvers I enstalled I dont mean to affend. I am just very excited about the fix..thats all and want others to benefit from it.

Tango
 
STATEMENT RETRACTION...PLEASE READ!

My friend who designed and fabricated these louvers has pointed out to me that I have made a mistatement about the direction in which my louvers point inside the cowling.

THEY DO NOT POINT TOWARD THE FIREWALL BUT TOWARD THE PROP. PLEASE SEE IMAGE SHACK PICS BELOW.

http://imageshack.us/g/571/cimg0109i.jpg/

In my vigor to report and share my results I mistakenly reported there position wrong. In addition, Van's pdf of there louvers shows them pointing toward the prop as well. Please guys forgive me here. All the results are the same, true and correct..I just mistakenly remembered it in my mind differently than it actually was. Very sorry for that.

Tango
 
Thanks for clearing that up, I was going nuts trying to figure out the air flow the other way. I like that placement a lot!
 
taverroi said:
No sir, dont have a rotax. I run an IO-360 M1B fuel injected engine. Please dont be affended by me being dogmatic about the results of the louvers I enstalled I dont mean to affend. I am just very excited about the fix..thats all and want others to benefit from it.

Tango
Click to expand...

No offense taken. I was just trying to ascertain what information applies to the RV-12 configuration, which is a bit different due to the design of drawing the intake air for the carbs from the inside of the cowling, rather than an outside source. One of the benefits I have seen listed for this design is that the intake air is warm air from inside the cowl, thereby eliminating the need for carb heat. I am just trying to make the point that the use of louvers in an RV-12 cowl could possibly produce different results than in a "conventional" configuration, because the additional venting of the cowl area will introduce a change in ambient pressure and temperature of the induction air.
 
Muffler is the problem

I was already sketching louver installations until I took a good look at the cowling and airflow paths today. I doubt that the louvers would help-- we already have about a 4" vent in middle of the lower cowl. It would be possible to put an additional louver on the pax side, but not on the left side-- that's where the duct for the water radiator is.

The REAL problem seems to be the location of the muffler-- mine is squarely behind the oil cooler with only a couple of inches clearance. My dimly remembered fluid flow/fluid dynamics courses all say that this is not good. The muffler prevents air from passing directly from the cooler to the exit. Air flowing around that big round muffler will have a lot of turbulence, etc that's not conducive to good flow-- not to mention the extra heat added by the muffler.

I'd think that getting the muffler up even an inch or so would greatly improve flow through the cooler. Could those of you have both "hot" and "cool" -12's in the same location take a look at the bottom of the muffler in respect to the bottom of the cooler? It might be worthwhile to loosen all the exhausts (again) to try to get the muffler higher up on the stub exhausts. Of course, then my exhaust wouldn't be the specified 4" from the cowling.

Didn't mean to start this long of a string!

FWIW, flew Young Eagles Saturday with OAT at 74 Deg/3500 ft and was still seeing 217-225 oil temps.

Wayne 120241/N143WM
 
No room

I agree with the "lack of room" for louvers in the 12's cowling. Has anyone applied muffler wrap insulation? or header pipe insulation wrap? These products are suppose to contain the heat until they exit the pipe(s) and help keep the engine compartment cooler on race cars. I'm not saying the 12 is a race car....but it sure is fun! Steve :D
 
Muffler

Wayne, I have been chasing FWF heat for several months, focusing primarily on possible fuel vapor issues. One of my mods was to have my exhaust stacks and muffler ceramic-coated to greatly reduce heat radiated from these parts. I have extensive "before" data from 5 FWF temperature probes and will be installing the coated pipes and muffler early next week for "after" data collection.

If you would like to explore this, the website is www.cradin.com

I don't have any interest in this outfit, even though they are in my home town. The process they do is used extensively by hotrodders for both exhaust heat control and even on internal engine components. The guy in charge is A&P/IA and has coated mufflers on certified AC. Send me a PM for details.

Jim
101F today
 
N223JH said:
Wayne, I have been chasing FWF heat for several months, focusing primarily on possible fuel vapor issues. One of my mods was to have my exhaust stacks and muffler ceramic-coated to greatly reduce heat radiated from these parts. I have extensive "before" data from 5 FWF temperature probes and will be installing the coated pipes and muffler early next week for "after" data collection.
Click to expand...

Was the chasing FWF heat in an RV-12?
 
Marty, Yes it was in the 12. Sorry I wasn't clear on that. For what it's worth louvers didn't do much for my 6A back in the day. Seems like everybody's plane is different.

Jim
RV-12 #264
Flying 25+ hours
 
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