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RFSchaller 09-13-2021 11:57 AM

Legacy R-12 Overheating Solution
I live in Phoenix. My 12 was licensed in 2012, and itís pretty much the original design with D180 avionics. In summer I frequently get CHT and Oil temperature alarms during climb out, and sometimes I just canít fly when it gets above 90F..

A few weeks ago I made some modifications suggested by my friend, Adam, at Flying Cacti flight school. I trimmed 3 1/2 inches from the lower cowl aft edge in the area of the cooling air outflow, installed two small deflectors just forward of the the edge on the outside to create a low pressure area at the air discharge and wrapped my muffler in a thin layer of exhaust insulation. Since then I have been flying in 98F temps and not picked up alarms although I still get into the caution range sometimes on climb out.

As an aside, Adam showed me the 12is his school is using, and he told me the relocation of the oil cooler and radiator have eliminated the overheat issue in the 12is.

Piper J3 09-13-2021 12:37 PM

Any chance of posting some photos? I'm curious what type of wrap you put on the muffler...

funflying 09-13-2021 12:39 PM

Could you post a photo of this modification or a link to a couple photos.

Piper J3 09-13-2021 12:53 PM

I would caution against using a woven fiberglass cloth for wrapping the muffler. I used high-temp wrap on the right front exhaust tube with the thought of shielding the oil line that passes through the loop. The fiberglass breaks down with heat and vibration over time and sheds glass fibers everywhere inside the cowling including on the air filters. It would be bad if abrasive fiberglass found its way into the intake manifolds…

NinerBikes 09-13-2021 02:27 PM

What, exactly, are you using for exhaust insulation?

Pictures and dimensions of 2 small deflectors, as well as aprox angle from existing surface?

How much additional drag, and or loss in airspeed noted?

RFSchaller 09-13-2021 11:10 PM

Iíll be out at the hangar Wednesday and get some pics. The muffler insulation I used was a sheet of fiberglass with adhesive on one side and shiny aluminum (?) on the other from Auto Zone.

Jcurry 09-14-2021 08:19 AM

I would also like to see dimensions and pics of your modifications please.

scottmillhouse 09-15-2021 08:24 AM

An old fix for the legacy 12 was to just move the oil cooler about an inch forward to give clearance from the exhaust. Easy to do during construction. After built I suppose you could cut oil cooler mount and overlap sides and add glass strips to anchor and just paint inside black. Worked great on my 12 with never any problem with high temperatures.

RFSchaller 09-15-2021 10:37 PM

I havenít had much luck posting photos, but here are two of the finished mod and two of one the removed sections.

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RFSchaller 09-15-2021 10:41 PM

OK. Try this link:

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