Elevator reassembly with replacement parts
A decision was made to purge any ribs where I had sought hole-matchup or corrected the thickness by re-forming some bends. This affected left and right elevator ribs 1, also right ribs 2 and 3. I also replaced the centre hinge, due to excessive enlargement of the 4mm holes due to the use and removal of the two stainless steel rivets (one was nearly 5mm), as well as significant elongation of the AN3 holes. I also replaced the control horn mount angles, since one had been previously damaged by a tool mark.
Duralac yellow was used with the AN3 hardware and the stainless steel rivets. The stainless steel rivets used had an appropriate grip range for the application.
When elongating the hinge holes, care was taken to ensure the hinge axis matched that of the elevator spar. A 1/4" chucking reamer was pushed into the hinge bearing, for a very tight fit. The reamer acted as a pointer allowing a high angular accuracy.
elevator rib 2
ribs 1 all came together with minimal forcing
AN3 bolt grip coated with Duralac Yellow, and torqued to 37 in-lb
304 stainless steel rivets used for attach control horns
Stainless steel rivets coated with Duralac yellow
AN3 and 4mm holes for hinge 1 all in spec and referenced to the spar channel and control horn mounting plates. Note better rivet tail due to use of 4x13mm rivets for the control horn brackets
However the hinge 1 holes do not quite match - they are slightly too far apart. Splitting the error between both side will require an elongation by about 0.1mm
The use of 4mm stainless steel rivets will prevent any lateral movement, while the AN3 bolts will provided the needed tensile strength
The control horn mounting brackets call for 4mmx10mm Gesipa rivets. These were considered marginally long enough given the total riveted thickness. Gesipa 4mmx 13mm polygrip rivets were obtained resulting a much more substantial rivet tail and much better mandrel retention
Author
This post is from Adam Dickson
