he nose oil cooler takes air from a NACA scoop installed on the left side of the fuselage. This opening was prelocated by the factory, and cut and installed it during Head Start much like the other NACA scoops. Then the supplied ducting was cut, the upper section was covered with foil tape and laid up with BID to create a mating flange on the lower (outlet) section. Then a hole was cut in the lower fuselage to allow the oil cooler to vent overboard. This is tricky all-round, and I chose to clamp the cooler in place on the NACA to get the best positioning possible (and still ended up back filling some).

Fitting the Oil Cooler Duct

Setting the Oil Cooler Duct

Next two holes are drilled in the duct for the hot air outlet, and the aluminum sheet is cut per the template to form the flapper valve. Once the hinge is attached to the flapper, it can be located and attached to the duct, and then the outlet tubes can be glassed into place and the control cable attached. Finally the oil cooler is attached to the NACA with #10 sheet metal screws.

Making the Duct Center Flange	Making the Oil Cooler Flange
Nose Cooler Duct	Nose Cooler Valve
Dry-Fitting the Oil Cooler	Protecting the Oil Cooler for Flange work
Setting the Outlet Ducts	Oil Cooler NACA Duct

Next, we added an additional cooler in the nose for supplemental heating. This cooler (or heater from the perspective of a passenger) will heat on very cold days were we want to recirculate cabin air through to warm it, instead of bringing in zero degree outside air. This was an idea from Bill Stockmon, a builder from Dayton who was kind enough to take me flying. He had rigged a somewhat less elaborate system of using a computer fan and things. We’ll be using a marine bilge fan and a permanently installed secondary heat exchanger, ducting, and 3-way valves to select which is active (on the oil side). My thinking is that I’ll switch over from say September to March here in Oil. As you can also see in the attached pictures we’ll be taking the cool air from the copilot side NACA duct and running it to mixing valve from Spruce along with the hot air, thus providing air of just the right temperature to the cabin (I hope, anyway). This should do away with the Cessna-style (exhaust muff) phenomena of getting no heat, or a rush of 150 degree air on your leg (especially nice in Fall when you’re wearing shorts, but it gets cool at altitude….). We’re also going to use the keel as a heater duct to route the air to the passengers (which is possible with the fixed gear plane, with far less equipment in there), which is an idea that the factory kind of liked.

Fan, heat exchanger, and exhaust plenum	Recirculation Heater Installed
Ducting from Front	Ducting from Rear
Heater Outlet Nozzles

Posted By: Brett Ferrell
Thursday October 10th, 2002 at 8:58 PM

Categories: Cabin Heat Engine Plumbing
Tags: Building Cooling Engine Fuselage Oil