In the recent days work was done to make the steps removable for maintenance purposes.
The manual calls for 4 mm stainless steel rivets, however that makes it very difficult to remove the steps which could be necessary for a couple of reasons (treatment of corrosion, repair in case of a damaged step). I didn’t want to make change to the fuselage so together with S2 builder Adam I came up with the idea to make doublers with anchor nuts for AN3 bolts. The only change would be to up-size the holes from 4.1 mm to 3/16″, this was approved by Sling Aircraft.
This is the design in SolidWorks:
The CAM was done in Fusion360:
The doublers were used as a jig to drill the 3/16″ holes:
When the primer was cured the anchor nuts could be installed:
The sharp 90 degrees corners were rounded and the holes up-sized to 3/16″:
The doublers are fixated with 3.2×11 mm rivets in the existing holes:
With help of the endoscope proper installation was verified:
Before the installation the conduits had to be removed. When the task was completed the conduits could go back in:
The center hole of the bottom flange conflicts with the weld, this was solved by a modified washer:
Final result:
