Pilots Seat - Part 1

A trial assembly of the seat showed that the seat would not just be a bolt in exercise. A quick call to the factory confirmed that the manufacturer was having problems with accurately inserting the attachment point's in the seat shell. While the seat can be installed it was not square enough for this builder, even with the brackets adjustment maxed out. 

This required a rethink.

As the problem was attachment position in relation to the brackets it was decided to break that connection. A piece of 2'' x 1/4''  2024-T351 aluminium was selected to allow the necessary countersunk screws and tapped holes to be installed. The first task was to define the relationship of the mounting holes to the seat body. Tape was located across the base of the seat using the molded crease line and a center-line was established and the bars located off these center lines.

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Locating the mounting bar

Mounting Bars

The bars were removed, drilled, countersunk and fitted to the seat shell using M8 X 10 countersunk Unbrako screws.

The next task was now to locate the seat in relation to the air-frame. This took a number of fitting with the brackets clamped to the longeron and resting the seat in the fuselage.

Seat Location

Stick Location

Seat aligned about stick center-line

A length of M6 threaded rod was inserted into the pilots stick using the front stop mount with the center of the cushion marked with tape as shown. The rod was centered by measuring its location to the frame. 

The back of the seat was positioned 185 to 190 mm from the side of the fuselage placing the side of the seat cushion at approximately 200 mm from the outside edge of the frame using the bulkhead as the reference between both sides. A final series of visual tweaks using the rod and center line on the front of the cushion finally located the seat. The first set of holes was transferred using a felt tip pen from the brackets to face off the front bar. With the seat removed both holes were tapped M8 through.

The bracket were mounted using M8 x 10 Unbrako cap head screws - reinstalled as per the above and the final holes marked on the rear bar. With the seat fully bolted to the frame the final check confirmed that the seat and bracket were in line and square to this builder satisfaction.

Brackets Mounted
The seat brackets inside face aligns with the inside
face of the fuselage longeron