Sunday, July 3, 2016

Instillation Of Throttle And Choke Cables Begins

Van’s instructs the builder to install the Mc Farlane Vernier-Assist  throttle cables first, feeding them through the grommet on the firewall and then through an Adel clamp installed on the engine mount. For both the throttle and choke cable pair’s one cable is longer than the other … the longer of the two is routed over to the right carburetor.  I quickly discovered the wires for the GPS 2020 antenna previously installed were somewhat in the way. There was not enough slack firewall forward to move the wires underneath the big Adel clamp mounted to the engine mount and the wires would have ended up wedged between the throttle and choke cable bundle and the big Adel clamp … this was not to my liking. Fortunately, when the Dynon GPS 2020 antenna was installed, the wires were cut so a little extra length was available behind the instrument panel. The down side is that the upper forward fuselage skin needed to be removed to gain access to the slack. So another minor setback was incurred and the upper forward fuselage skin was removed so the instrument panel is now opened up again. Actually, that is not a bad thing because I have an EAA tech inspection scheduled for next weekend … so they will now be able to have a look at the instrument wiring. After pulling enough slack forward to route the GPS 2020 wires under the large Adel clamp and out of harm’s way, the instillation of the throttle cables resumed.
Feeding the Mc Farlane Vernier-Assist throttle control’s two cable ends through the lock washer and locknut for the throttle control as it is being inserted into the panel hole.

With the throttle cables fished through the firewall grommet and into the engine compartment with the longest cable of the two closest to the right carburetor, the locknut for the throttle was tightened. This is a 1" nut and I quickly realized I did not have a wrench that size, so took a look in Mike’s hangar and fortunately there was a 1” wrench sitting on the table waiting for me to borrow it for a few minutes … thanks Mike. At this point, I realized it would be in my best interest if the autopilot disconnect switch were installed now because it would be easier to get a wrench onto the locknut without the choke control in the way … so it was rounded up and installed along with the associated Molex connector the wires slip into.

With the autopilot disconnect switch now installed, the choke control was installed next. The choke cable routing is through the grommet in the firewall and UNDER the throttle cables with the longest cable positioned closest to the right carburetor. The handle on the choke control locks in a closed position, so the cable is to be installed with the handle locked so it is in a vertical position.
Tightening the locknut on the choke cable assembly … the handle needs to be in the locked “off” position and vertical when the choke control is secured to the panel. The red autopilot disconnect switch and associated Molex connector can also be seen.

With the throttle and choke controls now tightened down, attention was given to the Adel clamp the four cables need to pass through. Unfortunately, in order to get all the cables through the clamp it was necessary to remove the bolt. This created a small problem of trying to get the screw installed again while fighting two clamps. The solution was to use a piece of safety wire around the Adel clamp attached to the engine mount and twist it tight enough to bring the ends of the clamp together so the bolt could be inserted through the smaller Adel clamp and slipped into the hole in the other clamp without a fight.
The mounting screw for the Adel clamps was left lose so once the four cables are connected to the carburetors, the angle of the clamps can be adjusted to prevent the cables from rubbing on the engine mount they are sitting on now. The grey and orange wires with the do not remove label on them are the GPS 2020 antenna wires which were routed so they now pass below both Adel clamps.

The next step will be installing the throttle and choke cables to the Rotax 912's carburetors ... which will hopefully be accomplished during the next work session.