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  #1  
Old 06-09-2011, 03:24 PM
yankee-flyer yankee-flyer is offline
 
Join Date: Jun 2009
Location: Dayton, OH
Posts: 838
Question Oil Temps???

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
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  #2  
Old 06-09-2011, 03:47 PM
N223JH N223JH is offline
 
Join Date: Apr 2008
Location: Boerne, TX
Posts: 228
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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
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  #3  
Old 06-09-2011, 05:28 PM
meadeduck meadeduck is offline
 
Join Date: May 2008
Location: Marietta, Ga.
Posts: 220
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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
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  #4  
Old 06-09-2011, 06:12 PM
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MartySantic MartySantic is offline
 
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Location: Davenport, IA
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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?
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  #5  
Old 06-09-2011, 06:27 PM
yankee-flyer yankee-flyer is offline
 
Join Date: Jun 2009
Location: Dayton, OH
Posts: 838
Talking 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
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  #6  
Old 06-09-2011, 06:51 PM
vernhendershott vernhendershott is offline
 
Join Date: Dec 2007
Location: Spruce Creek, FL
Posts: 370
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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
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  #7  
Old 06-09-2011, 06:56 PM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,647
Default 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.
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  #8  
Old 06-10-2011, 05:40 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
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Quote:
Originally Posted by vernhendershott View Post
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
Hmmmm - I wonder how accurate the temperature probes are?
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  #9  
Old 06-10-2011, 06:20 AM
vernhendershott vernhendershott is offline
 
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Location: Spruce Creek, FL
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Quote:
Originally Posted by BigJohn View Post
Hmmmm - I wonder how accurate the temperature probes are?
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
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  #10  
Old 06-10-2011, 06:43 AM
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DonFromTX DonFromTX is offline
 
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Location: La Feria Texas
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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.
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