RV9/A Flying in Summer

[RVbySDI]

Originally Posted by N797EJ

Hello all!

New RV9A owner. What an awesome airplane, it’s been great so far. We moved the airplane back home to Arizona. As you can imagine it’s starting to heat up here. We have noticed on climb out the airplane CHT’s and oil temp are getting hot. We have to lower the nose and pull back some power to help. Very slow climbs. We are trying to see if anyone has made any baffling modifications or and modifications at all to make these temps a little better has Arizona heats up?

On average we see about 425 degrees to 435 degrees something on a full power climb out. We don’t spend any time at that temp. We try out best to lower the nose and get those temps in the lower 400’s. On the oil temp we see something similar, 185 degrees on climb out and then in the low 170’s at cruise. Thank you all for any insights!

There are a lot of suggestions about baffling, cowl flaps, etc. all may be needed, eventually. However, before any of that happens there is a lot more information you could provide that would help clarify the cause of your problem.

So, other than you have an RV9 in Arizona that you climb at full power, tell us more. What engine? Carb or injected? Electronic ignition or magnetos? Constant speed or fixed pitch prop? What is the timing set at? What speed are you climbing at full throttle? Answers to these questions can go a long way toward analysis of your situation.

[hpdmp3486]

Live in Texas. Have an RV9A. IO-320-D2A, fixed pitch Cato prop. I to have the same issues. I have a long taxi out, by the time I get to run up, at 400 on engine temp. On takeoff will level out to get temps down. I just installed the Anti Splat EZ Cool flap, will start testing it shortly.

[Dugaru]

One additional data point. I tried closing the oil cooler shutter on takeoff today, and did indeed get a significant increase in cooling for my #2 cylinder. Have to repeat the test a few times, but it looks like I’m getting at least 15 degrees improvement. Oil temps were higher of course, but still well in the green.

[edhunter]

Originally Posted by Dugaru

One additional data point. I tried closing the oil cooler shutter on takeoff today, and did indeed get a significant increase in cooling for my #2 cylinder. Have to repeat the test a few times, but it looks like I’m getting at least 15 degrees improvement. Oil temps were higher of course, but still well in the green.

Several months ago I was chasing a "too cold #2 CHT". It was running some 40º cooler than the other cylinders. EGTs were good. I checked everthing to figure it out - swapped/replaced plugs, checked for intake leak, swapped injectors, swapped cht probes, checked compression, scoped the cylinder, ohmed the plug wires, checked timing... Everything was perfect and nothing changed the CHT. Sometimes after flying for a couple hours or so the CHT would normalize with the other 3. Finally decided it was due to the recent install of an oil cooler shutter, and altering the airflow through the oil cooler significantly affected the #2 CHT. No considering increasing the size of the cowl dam in front of #2.

[Dugaru]

Similar experience here. After all the tweaking I did to get #2 to run cooler, nothing even remotely compares to the effect of just closing the freaking oil cooler shutter.

Starting to think that if I put another shutter (sans oil cooler) in the same spot behind cylinders #1 and #3, I could fiddle with the position of both and get just about any CHTs I want!!

Originally Posted by edhunter

Several months ago I was chasing a "too cold #2 CHT". It was running some 40º cooler than the other cylinders. EGTs were good. I checked everthing to figure it out - swapped/replaced plugs, checked for intake leak, swapped injectors, swapped cht probes, checked compression, scoped the cylinder, ohmed the plug wires, checked timing... Everything was perfect and nothing changed the CHT. Sometimes after flying for a couple hours or so the CHT would normalize with the other 3. Finally decided it was due to the recent install of an oil cooler shutter, and altering the airflow through the oil cooler significantly affected the #2 CHT. No considering increasing the size of the cowl dam in front of #2.

[toc pilot]

I live in Tucson and I know about hot weather days. Also, I am running a AEIO-390xi fuel injected Lycoming putting out 210hp+.

I installed louvers and they work great! During the winter, I install blank aluminum plates instead of the louvers. Easy to install and also the best way to keep things cool.

As suggested above, verify your timing first. This has to be verified as a mistimed engine will surely heat things up quickly!