Brief Description: Fabricate Flapper Valve for oil cooler
Started fabrication of aluminum flapper valve for oil cooling/cabin heat. Started with a cardboard pattern using the pattern in figure 12-9 of the manual. The duct in which this valve fits is a complex piece such that it is impossible to shape the valve such that it completely closes of the air outlet duct. (If the shape were made exact to the inside dimensions of the duct, it could not be raised to close off the heater ports.)
I chose a hinge point for the valve that was the same as the line on the duct provided by the factory. Working from there, using trial and error, I cut, sanded, and shaped the valve to fit precisely as possible across the duct. I did this by drawing a grid of sorts on the valve and shaving off where necessary.