Thursday, August 1, 2013

Fuselage Wiring Harness, Part 2

One of the concerns I have had during the process of installing the fuselage and optional wiring harnesses was the lack of room running down the centerline belly of the aircraft.  With the flap handle and other protrusions from the top down, it was apparent that getting it all into place was going to be tight!

Vans had made a couple of nice additions to the Finish kit to address this situation.  One is a "shield", which is just a thin sheet of aluminum with bends and flaps in all the right places, that runs between the first two system blocks and helps hold down the wire bundle beneath the flaperon mixer as shown below.  It may be hard to see it as it blends in with the primered bottom skins, but it is there doing its job in the next two photos.



A similar shield is also fitted beneath the flap handle pivot blocks which also does a superb job of holding down the wire bundle into a nice low profile, clear of the pivoting torque tube, as shown below.


As mentioned in the Part 2 installment of the Flight Controls blog, a relay deck was to be incorporated into my dual Tosten control grips (with hat switches) installation.  These grips will allow control of the electric pitch trim via their hat switches.  The problem is that if both pilots simultaneously initiate trim commands, a short circuit situation can result.  The relay deck creates an electronic interlock which precludes that circumstance.  Below is a shot of the relay deck and its instruction sheet.


A couple of nutplates were carefully installed on the relay deck and installed just below the power outlet, on the inside of the seat bottom, as shown below.  Eight, #24 leads are used to interface the servo with the Tosten grips along with power and ground.


I have elected to use spade connectors to facilitate easy removal for troubleshooting/maintenance.  I should also add that my installation includes wiring of the stock panel-mounted toggle switch in parallel to the hat switches, so "you can have your cake and eat it too."


Pictured below is a crude representation of the wiring for the electric pitch trim system as I plan on incorporating into the aircraft.









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