Things You Wish You Knew Before Buying Your CT

[sandpiper]

On 5/13/2022 at 4:39 PM, 207WF said:

Engine overheating  in the climb in hot wx.

This has been the most significant downside to the plane.

WF

I agree.

[Anticept]

Your oil or your coolant is overheating?

If it's oil, you don't have enough in the reservoir. The recommendation is actually to fill it to the max line when cold. It will give you a lot more time on a long climb before it gets hot, and willl lower the maximum temp a bit. The oil reservior is also a heat radiator.

If it is coolant: get your radiator blown out with mineral spirits then alcohol using an engine bay aerosolizer cleaner. Let it sit for a couple hours cowling off to dry. Adjust the radiator so that it is facing as flush with the cowling as possible without resting against it. You might have to trim the cowling a little, you also might have to make a metal extension for the bottom radiator mounting bracket so that it can come forward. Maintain top and bottom baffles. Also make sure the coolant is topped off in the bottle on top of the engine.

[Towner]

Took off today with a ground temperature of 96 degrees. Did a cruise climb at about 90 knots. Oil temp was right at the top of the green with an occasional flash of yellow. Is this normal?

Climb was to 8500. Once level, oil temp dropped to middle of green. Sorry, didn’t get numbers, just colors.

[Anticept]

Arcs don't really help here because of a number of configurations over the years.

For example, the CHTs are now coolant temperature sensors, a change made around 6 years ago. That is a pretty significant change, but Flight design has always used coolant temp limits. The older true CHTs always reads hotter, but the real engine limits are higher despite the arcs.

[sandpiper]

Corey,

My problem is oil temperature. Low oil is not the problem. Tank is full. I fill to the max line, fly, then make sure it's at max before burping.

My airport is 175 ft MSL. Taking off on an 80 degree day, climb clean with full power, I'm lucky to make 3500 ft without being in the yellow. Once in the yellow it's a rapid transition to red if I don't stop it.

The first summer I had it, 2007, I don't recall this problem. The only change I made was sometime during winter of 2007/2008 I repitched the prop from flat out 5300 to 5600. Then, in summer of 2008 the problem started. 

[Anticept]

Given how long ago that this was, I am not sure that just asking questions will help, I can only just share what I did with mine.

My airport is 900 feet MSL. I too was having the problem recently where oil temp would rapidly climb.

The first thing I did was really, really blow out my radiator with mineral spirits. And I worked at it for a while, went through a whole gallon with the engine cleaning wand I was using because it kept removing more and more dirt. Note that it is an aerosolizer with a very high power nozzle, that is hooked up to an air compressor, and barely draws cleaner. Enough to mist and mosten surfaces, while the air blast does the work. To go through a gallon is really saying something if you used the settings I do.

Anyways, there was quite a lot of trapped debris deep in the fins. There is a small gap between the coolant radiator and the oil radiator, and things can get stuck in there. After doing this, I could see light pretty clearly through both the coolant and oil radiator fins for the first time in a long, long time.

Next, I had to trim my cowling a little, but I made adjustments to the radiator, both in replacing the rubber mounts, and also properly aligning it. My radiator wasn't just misaligned vertically, but I found out it was also about 3/4 of an inch off to one side. Once that was fixed it had much better clearance to be realigned verfically. I also made an extension for the bottom bar to swing out the bottom of ghe radiator better. Fixed up the baffles too.

Lastly, I fixed the clearance between the oil radiator and the cabin heat hose. The hose needed some reforming so that it didnt rest against the back of the radiator.

These items made a significant impact on cooling, to where it has to be 90+ degrees out to put oil in the yellow zone,.and I haven't seen it get close to red since doing this, temps top out at around 230F, about mid way through yellow, after doing a 4000 foot climb at Vy.

Finally, and this is important: long taxiing and run ups will result in overheat before you even get off the ground. There is not enough static pressure without ram air. If you have lengthy ground running time, you might not make it to cooler air before overheat at Vx or Vy.

Many aircraft also have a cruise climb recommendation in hot temperatures. We don't have such a thing, but try adding 10-20 knots to Vy if you're getting wwarm

 If you have a thermostat, and its the one off to the right side (permacool), then it never completely shunts oil to the radiator. If there's some reason why your oil radiator is restricted, then cooling capacity will be severely reduced. Check that as a last resort, try at minimum to really get the fins clean first.

[sandpiper]

Thanks Corey. 
No oil thermostat. I’ll work first on cleaning up the fins. My plane is definitely a bug magnet. 
I wonder if vg’s would help get more air into the radiator?

Edited May 18, 2022 by sandpiper
Left out the word “air” in last sentence.

[Anticept]

VGs would not. Their purpose is to add energy to the boundary layer so that it stays stuck to the airplane's skin longer. Radiator efficiency is going to be directly related to static pressure differences and cleanliness of the fins

Edit: this is what I use for engine bay cleaning: https://www.harborfreight.com/engine-cleaning-gun-68290.html

Use it on a medium air pressure setting when cleaning the engine and around parts, turn it up really high for blowing out the fins. The screw on it adjusts the amount of cleaner being drawn in, set it so that it is shooting a cloud of cleaner, not a stream of it. The air blast does the scrubbing, the cleaner loosens the grit.

I use only mineral spirits and following up with isopropyl alcohol in mine (>90%). Mineral spirits leave residues no matter what the tin says, isopropyl cleans it off.

[tevbax]

To bring this full circle, we finally closed on the airplane this morning. I am now one of 4 owners of a CTSW. 

This board has seen the sale of this plane before, N906LW. BRS is out for a repack at the moment and absolutely cannot wait to get some air time. Right now, i'm making copies of the POH for everyone, and tying up a few loose ends (registration/ insurance/ etc). 

ADS-B is being upgraded to the uAvionix tailbeacon, and we need to have the transponder 2 year check done. Other than that, the plane is in excellent shape. 

Located at KPCZ in Waupaca, WI. 

Thanks everyone for your feedback! 

Mike

[Jim Meade]

You'll taxi to Oshkosh?  :
 

Congratulations and many happy flights.