mocfly Posted April 17, 2012 Report Share Posted April 17, 2012 I was looking at the way the radiator sits in the cowl relative to incoming wind and wondered if the reason we have such a problem with high oil temps is directly related to the air not going thru the radiator. My thought is to create a multi shutter device which moves the air relative to the wind and create more direct flow thru the radiator. Anyone have any thoughts or has anyone experimented with this? Just a random thought. Link to comment Share on other sites More sharing options...
Roger Lee Posted April 17, 2012 Report Share Posted April 17, 2012 You shouldn't have high oil temps. Most of us don't. The cause could be too much prop pitch. Max WOT rpm should be between 5500-5600 rpm. Does it only over heat on climb out? Do you use Evan's coolant? Something is different we just need to pin point it. Link to comment Share on other sites More sharing options...
mocfly Posted April 17, 2012 Author Report Share Posted April 17, 2012 Roger, The prop has been re-pitched to achieve the 5500-5600 wot. I did notice tHat the temps ran higher after the oil thermostat was put in than before. About 60 degrees warmer. Now it runs right at the top of the green (230) and maybe higher if I don't watch it closely. That 230 was at 5250 and oat of 60f Chris Link to comment Share on other sites More sharing options...
mocfly Posted April 17, 2012 Author Report Share Posted April 17, 2012 Changed from Evans to dex for coolant. Link to comment Share on other sites More sharing options...
Roger Lee Posted April 17, 2012 Report Share Posted April 17, 2012 And the WOT rpm? Link to comment Share on other sites More sharing options...
mocfly Posted April 17, 2012 Author Report Share Posted April 17, 2012 Roger Its 5500-5600 rpm Link to comment Share on other sites More sharing options...
Roger Lee Posted April 17, 2012 Report Share Posted April 17, 2012 Hi Chris, I should have ask this one in the first post what are you seeing for the oil temp? These next temps would depend on OAT, climb v.s. cruise and altitude. I would consider anything up to 235F very normal, 235-245 a little warm (usually seen in climb), but not overly worrisome and 250F tolerable for the short climb (usually over pitched prop, using Evans or too much climb on a hot summer day really loaded), but too high for sustained flight or cruise. Anything past 250F is too high and the cause needs to be found. High temps with oil and CHT/coolant can be helped by having the proper WOT rpm setup and then in cruise rpm (5100-5300) the temps tend to be down. On hot day and a heavy loaded aircraft then less climb rate is always best for temps. Take off flatter and with more speed for more airflow and less loading of the engine. Running in the mid to upper 4000 rpm range also causes higher temps. That is due to a slightly leaner carb setup from the factory in mid range and the engine wasn't designed to run there. Link to comment Share on other sites More sharing options...
mocfly Posted April 17, 2012 Author Report Share Posted April 17, 2012 Roger, Here are 2 pics. Picture one is prior to coolant change and thermostat install. OAT was 65 deg in cruise Picture two is in cruise with an oat about 70. Chris Link to comment Share on other sites More sharing options...
Roger Lee Posted April 17, 2012 Report Share Posted April 17, 2012 Hi Chris, Pic one is within limits and not too hot, but there is a pretty fair temp span between the oil temp and CHT. I take it that is the Evans. Pic 2 is actually a little on the cool side. In pic 2 the CHT is out of the pic. Link to comment Share on other sites More sharing options...
mocfly Posted April 18, 2012 Author Report Share Posted April 18, 2012 Roger, If I move the needle clip to a richer position (your gonna have to refresh my memory which number it is) do you believe it will help? I read that some people use -6 and 80 knots in the climb saying it helps. I was told never to go - flaps until over 100 knots. Can I get your thoughts on this? I would have thought that a thermostat will regulate the temperature to maintain a set temperature? What I am seeing is not making sense to me. I know some of us have issues and others do not. Maybe we have one of those which always run "warm" Link to comment Share on other sites More sharing options...
Jim Meade Posted April 18, 2012 Report Share Posted April 18, 2012 The Vfe for 0° flaps is 100 KIAS, so you should be going to negative flaps before that. Per the POH. For CTSW. Link to comment Share on other sites More sharing options...
bitten192 Posted April 18, 2012 Report Share Posted April 18, 2012 I was looking at the way the radiator sits in the cowl relative to incoming wind and wondered if the reason we have such a problem with high oil temps is directly related to the air not going thru the radiator. My thought is to create a multi shutter device which moves the air relative to the wind and create more direct flow thru the radiator. Anyone have any thoughts or has anyone experimented with this? Just a random thought. REMOS has a oil cooler shutter fitted to the oil cooler frame. Pretty simple and effective. Push-pull knob on the control panel. Probably could be fitted to the CT but would require an LOA unless you are ELSA. Ernie Link to comment Share on other sites More sharing options...
coppercity Posted April 18, 2012 Report Share Posted April 18, 2012 I generally always use -6 flaps after leaving the pattern and climb at 78kias for Vy and cruise climb at 90kias. Our summer temps can get to 100-115F OAT so on those afternoons I occasionally have to throttle back to 4800 in the climb to keep the temps in the lower yellow, but most the time full throttle climb even at those temps is not a problem. Yes you should go to -6 before exceeding 100kias. Link to comment Share on other sites More sharing options...
FlyRatz Posted April 18, 2012 Report Share Posted April 18, 2012 I have had temperature problems with a CTSW, which had the thermostat option installed. This engine used to run as cool as almost all CTs do. But the temperatures rised up very little but continuously over time and one day the critical area was reached. Ater a long journey of tests and diagnosis, I could not find the reason for the high temperatures. Then I brought the water radiator to a radiator repair shop, which is able to do some measurements about the performance of the radiator. This was my golden shot. They found out, that the radiator had only 30 % of its capacity left. A new radiator then did the job and the engine runs as cool as ever. Maybe it is worth a try? Good luck Markus Link to comment Share on other sites More sharing options...
Roger Lee Posted April 18, 2012 Report Share Posted April 18, 2012 Hi Chris, Does your CT have the oil and coolant thermostats? I'm not quite understanding and maybe I have the pics backwards from what you are trying to show me. If pic 2 is with a 50/50 coolant then you don't have a heating issue at all. Your oil and or CHT's are better run between 200F-225F for the everyday numbers. If during the warmer months you are around 235F don't sweat it. As far as running the -6 flaps below 100 it is absolutely not an issue. The numbers in the manual are a general guide so people will have some idea of where and when, but they aren't etched in stone.The CT should not stall at -6 above 45 knots loaded. This is what allows it to be in the LSA category. I would stay in zero flaps and climb around 80-90 for better cooling. You can approach and land with -6 at 60 knots any day of the week if you had to. The one issue I see CT owners trying to do is switch to 15 or more flaps at too high a speed which really stresses the flap motor. The needle clip position in the carbs are at the #3 slot, but I wouldn't mess with this. It isn't your issue if you have one and before I would do that it would be nice to have some more numbers to work with. There are 2-3 other items that can cause higher than normal temps that should be ruled out. Give me a call. Link to comment Share on other sites More sharing options...
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