RV-9A 13B Cooling

[dlomheim]

I am installing a 13B in my 9A and have the Sam James "Rotary Cowling" and so am wanting to keep all my coolers under the engine to max extent possible. I therefore was wondering if any of you have ever seen a long and narrow radiator (say 40" X 8") that might fit the bill and allow a more vertical installation of the radiator face to the relative airflow. I am just pulling the 40 inches out of thin air and need to measure the actual width I have to work with next time I'm out in the hanger, but conceptually I was wondering if there are possible strength / longevity or degraded cooling issues that something like this might cause. I also sometimes wonder if it wouldn't be better to just mount my Mazda oil cooler which is already fairly stubby out under a wing like the Spit or ME-109 but can't see a good way to plumb it from there without making Van mad about messing with his beautiful wing...

Thanks for any comments.

Doug

[rv6ejguy]

I don't think you will have 40 inches of width available but this would be very difficult to duct effectively anyway without a lot of flow separation at the ends. You'll probably have to get a custom core built no wider than 24 inches plus tanks. Seal the rad tightly to the intake mouth and if the divergence angle exceeds more than about 7 degrees, internal guide vanes will help turn the air without separation. You probably want a minimum of 150 square inches of area and double row, 1 inch or 1.25 inches tubes.

Wing mounted rads on an RV with the front attach point and inboard fuel tanks looks like a total pain to do cleanly and safely. A plumbing nightmare. Getting air to the oil cooler will involve some more thinking. Might want to try a water to oil cooler and just dump all the heat into the coolant. Make the rad about 25% bigger if you go this route.

[Ironflight]

I don't know nuthin' about water cooling Doug, but it's great to hear that you are still pluggin' away! Maybe I need to pay another visit and give you a ride in the Val to keep you motivated - if the dang storms between here and OKC every let up....

Paul