Sunday, October 01, 2006

Return of the Wooden Mock-up

I did this once before. I took some measurements to make a wider airplane than the plans call for. The measurements were approximate because at the time I thought that I would make the airplane taller as well, in order to acommodate the protrusion of my head above the seat back bulkhead, "C." I also had not made an attempt to accurately form bulkhead "D", the bulkhead that is midway down the fuselage behind the cockpit. I knew "D" would not fit when built according to the plans but I wanted to wait until I was comfortable with the height of "C."

This month I refined my wooden mock-up and incorporated some smaller changes, to the spars, and the height of bulkhead "B", the instrument panel. I now have better measurements. There is also a discrepancy in the length of the top of the rear fuselage. The plans mention 72 inches but I am coming up with 70. The flat bottom of the fuselage is 72 inches, from the trailing edge of the wing to the end of the tail. The difference between the 70 and 72 is due to the set back angle of bulkhead "C", at 20 degrees aft of vertical according to the plans. The plans don't provide a side view so I am assuming that all bulkheads are parallel. At least, that is the way I am building the fuselage!

I have made numerous drawings to try different sizes. If bulkhead "E" is built according to plans then "D" won't fit. If "D" is built according to plans then "E" must be much taller and wider. So "D" is now fixed and I am getting the dimensions set for two more bulkheads as well.

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