Control stick installation has begun.
This part came pre-assembled at the Sling factory, and I took it apart, well sort of...
I removed the control stick from the assembly and sent it off to be powder coated. During final assembly it will sill need to be cut to length, but that is a problem for another day.
Prior to final installation of the left and right control tubes I marked, drilled and riveted the bushing locking collars in place. This did require these parts to be temporarily installed to mark where the locking collars would site without binding on the bushings.
I had issues with binding on these bushings, so I used the same techniques described in the elevator torque tube sections so that I have a nice fluid range of motion.
Adding Lithium grease on these bushings really helps reduce overall friction in these areas.
Tip #1
Prior to finial install, multiple builders have recommended pre-installing the eye bolt hardware as well as the control stop spacers.
Tip #2
Although the finishing manual does not specify the installation of both control stops on each control tube, I followed the advice and experiences of other builders and used all four control stops, two per side.
This change did require longer bolts to be used HW-ANB-416 (AN4 - 16A Bolt)
Using both control stops on both tubes makes it really easy to align the control sticks using the aileron push-rod tube.
Tip #3
I also installed the Garmin GSA-28 aileron servo before this section becomes too cluttered with control linkage making it difficult to access.
Access to mount the AP servo using the bolts specified in the KAI are a challenge because it is mounted inside the spare carry-through and the bolt lengths are short.
With the control tubes installed I needed to secure the aft bushing mount to the cross-member on the spar carry-through.
The instructions for this section are pretty much non-existent and the quantities in the inventory do not align with the requirements, correct quantities are listed below.
- (8) - HW-SBM-416 (M4 x 16mm) button head screws
- (8) - HW-MTW-040 M4 Washers
- (8) - HW-MTL-040 M4 Nyloc Locknut
Tip #4
I replaced the factory supplied HW-SBM-416 (M4 x 16mm) button head screws with shorter (M4 x 14mm) because it is impossible to insert these screws without damaging the threads using the length supplied by the factory.
You can see in the picture below that it still requires some force to push the screws into place. (scratches on the spar carry-through top plate)
You can see in this view the the slightly shorter screws still expose more that enough thread after the Nyloc locknuts have been installed. I could have probably used an even shorter (M4 x 12mm) based on the length exposed, however; changing it now would not result in any improvement.
Tip #5
Some builders have been instructed that they may need to slightly bend the support bracket that carries the bushing to improve alignment if there is excessive binding. I wasn't aware of this at the time so I struggled with sanding the split bushings to get the proper fitment.
Notes:
1. Installing the eye bolts and aileron linkage ahead of time will make things far when connecting everything during final assembly.
2. Completing the push-rod installation outlined in the finishing construction manual will also help to close-out this section and test all of the control linkage prior to final assembly.
