Yes, I have split the inlet in the cowl. In the picture, the smaller (right) portion goes up to the oil cooler. The larger (left) portion is for the water cooler. You are right on all your presumptions, Sam James cowl, griffin radiator, oil cooler on the right side of the engine.
I flew her again today, but didn’t get great results. Here is the data:
Renesis, RD-1C, BIG FAT CATTO prop (76 x 88)
Static RPM max = 5000
67* outside air temp
Rolling down the runway, the max RPM was 5300
Best speed I got was 70 KTS
At 1500 feet, I pulled the power back with water temp at 210 (it peaked at 230, but by then, I was at idle)
Pulled closed and landed, 190 on both water and oil temp at landing.
Water cooler inlet is 36 sq in.
Exit at the back of the cowl for water and oil cooling air, and exhaust is 67 sq in.
I have a couple of ideas. One is that my exit isn’t large enough, so I am backing up air, and not getting proper cooling.
Second is that the shape of my duct isn’t good enough. I think I can check this using a manometer (may be spelled wrong), but I would like some directions on how to accomplish this.
Third, I may be getting some blow-by at the bottom of my radiator. If the fiberglass cowling bows out due to pressure in the intake duct, I am loosing cooling. I think I can check this by tying the plane down REAL WELL, running the engine up to high power setting and looking into the cowl exit. If I see daylight below the radiator, I know I have blow-by.
Fourth, the prop is so big, that the engine can’t pull the plane through the air enough to get fast and create better cooling flow. If I have to keep full power and can only generate 70 kts, the radiator will never keep up.
Looking for inputs and comments from the group.
Chris
WOW! That's exotic! I presume you have a Sam James Rotary cowl? I built a chin scoop for a griffin radiator, but it's just a simple scoop with no upper lip.
I have the stock VAN's RV-8 cowl, so I take oil cooler air from the right cowl cheek; it looks like you have the oil cooler on the right side and take that air from the right side of the chin scoop?
I too did concept testing on my partially completed scoops and diffusers. Once they proved good I continued with the finish work, and you know what? they worked even better as finished parts than the tape and cardboard test peices.
I’ve finally installed my new radiator and built the ductwork. The sides and top are completed with fiberglass, the bottom is just the foam, covered with duct tape. It will hold the shape, and can’t fall out or move. So tomorrow I test it out.
I’ll post the results tomorrow.