The pattern made yesterday was transferred to the SS sheet that will be used to cover the Fiberfrax. I chose SS so that it can maintain its mechanical protection of the Fiberfrax even in a fire. The aluminum that is specified in the plans will not hold up to a fire for very long. Some have reported the results of tests with a flame impinging on the aluminum that it will not last more than 30 seconds. The SS should last much longer. However, it is also heavier.
I have layed out the cut so that there are two halves. The bottom half will start at the top of the spar. The top half will overlap the bottom by about 1/2". I used metal shears to cut along the lines to cut out both halves.
The bottom half was trial fit and some adjustments were made along the bottom corners. I used the rudder bracket bolts as a finder. I used the hammer to "punch" the metal. Then I drilled a small pilot hole to verify location and then used a step drill to opern it up.
As I had feared, these were slightly off from the original marks on the paper template; therefore all of them will be off some. I fastened the sheet down and from the inside, painted through the holes to locate all of the holes. I will let the paint dry and tomorrow I will cut/drill them out.
A large wire penetration was installed on the lower firewall to allow the engine sensors wiring through. It is being protected by a stainless flange and pipe. Fire wrap will be used to fireproof the opening.
