Hot CHT's, bonding AL to Cylinder for improved flow

[JeanAlesi]

We are testing a turbo normalized system on a TCM IO-550 engine. At 25,000 FT, the converted CHT and OIL Temps. per FAR 23 are above the redline. We have enlarged the inlet and cowl flap areas and it did improve the temps., but did not lower them to a desirable value. Instead of re-enlarging the areas and increasing the cooling drag, I am thinking of modifying the baffle between the cylinders to prevent the airflow from flowing down between the cylinders. i.e: blocking that area. To modify the existing engine supplied Baffle I think will be a hassle. I am thinking of just bonding a piece of aluminum between each cylinder to accomplish that task and see if it will have any noticeable effect. My concern is if the bond will be able to withstand the high temp/vibration loads. Does anyone have any experience in this area and/or some thoughts about this?

Any input is well appreciated, thank you in advance.

P.S: As this subject is related to thermo and aircraft engineering, I will post this thread in both forms.

 

[JayMaechtlen]

So, you will re-direct flow away from the cylinders to the heads and oil cooler?
what happens to the cylinders without cooling?
regards


Jay Maechtlen

 

[Michael996]

Jean,
I am assuming I am telling you something you already know. But, just in case;

Make sure, you have the maximum fuel flow requirements set up properly. It is very important that you have the engine set up so you do flow fuel at the red line values. And, check the calibration of the fuel flow meters you use. Most cockpit fuel flow meters are pressure gages.

 

[Michael996]

Oh, one more thing. If you haven't visited these, read them with a lot of scepticism.

http://www.avweb.com/news/columns/182544-1.html

 

[JeanAlesi]

Thanks for your responses guys. I am not redirecting the flow away from the cowling fins, but rather preventing it from escaping to the lower compartment (bottom cowling area). The fuel flow requirements are set properly per our flight tests. I did manage to design a bracket that I will support on the existing baffle, then "wrap" bend it around the inside of the cylinders and block the escape area, I have yet to see the flight test results.

That link looks good, I will check it out.
Regards
Raffi A