Flight Controls, Part 3

After finishing the painting of the flap handle and the completion of the wiring harness, it was time to continue the flight controls installation.  First order of business was to install the rod end bearing into the flap handle's pushrod and then connect it to the flap handle.

 Prior to the flap installation, the brake reservoir was installed and then a tee was threaded into the unit followed by the remaining 2 brake lines installed into the tee as shown below in the following 2 pictures.

Next, the flap handle blocks and the flap handle assembly was installed between the seat ribs, on the centerline.

The flap handle pushrod and flaperon mixer were bolted to the flaperon mixer arms as shown below.

The control stick pushrods are now installed from the base of the control sticks to the forward end of the flaperon mixer as shown below.

The flaperon pushrods are attached to the aft end of the flaperon mixer.

 

Another shot of the flaperon pushrods and their forward attach points.

The aft end of the flaperon pushrods are attached to the flaperon torque tubes, which are hinged onto the bearing brackets.

 Next, the flap detent bracket is riveted to the plate and angles in preparation for the fitment of the flap fork assembly inside of the flap handle assembly.

 The flap detent bracket assembly is slid through the flap handle with the internal flap fork assembly, which includes the compression spring.  The detent assembly is screwed into place with shims, which will simulate the cover plate.  During this process, the length of the internal fork assembly is verified to insure that the flap knob (button) does not extend too far beyond the length of the flap handle.  I installed 2 other springs (less stiffness) after builder complaints of the stiffness of the original.  In the end, I chose the original, stiffer spring for my flap handle assembly.  When the flap moves from one position and locks into the next, it sounds like a rifle shot!  Quite a reassurance that the flap handle is locked into its position.

Fuselage Wiring Harness, Part 3 (Final)

After the relay deck was successfully installed and tested, I discovered that the Dynon Skyview avionics system features a speed control.  Since I had opted to move the pitch trim from the instrument panel's rocker switch and associated features with Skyview, I learned that I needed to provide an external speed control.  The pitch trim servo, without any speed control, will run stop-to-stop in 12 seconds.  Vans prescribes 25-30 seconds for full travel of the servo.

After a friendly consult with one of the electrical experts on Vansairforce, Joe Gores, I learned that I was a mere $15 Ebay transaction away from purchasing a ready-made external pulse width modulated (PWM) speed control.  Connections involved 12 volts power, an airframe ground and then the ground from the relay deck and its speed control input wire.  The little controller works like a charm.  It even provides a knob that you adjust to attain the desired servo motor speed, so I am set!  Thanks Joe!!!

Here are a few shots of the PWM speed control and its relative location.  It has been installed with some outdoor permanent double backed tape.

After the speed controller was installed and tested, it was basically time to finish bundling the 2 main wire harnesses (fuselage and options).  Below is a picture of the wiring shield and the wiring bundle hangar that constrains the wiring harnesses as they run beneath and below the rudder pedal torque tubes.

 One of the ongoing aggravations I have experienced with the wiring tasks has involved the use of micro-fit connectors.  At this point I am completely abandoning their use in my airplane.  Even with the use of a fairly nice ratcheting crimper, I have struggled to get a consistent, quality crimp on the tiny little buggers.  What's more, I have also had inconsistent results with their remaining securely captured in the Molex connector body.  In light of this I have gone away from them entirely and moved to conventional fast-on connectors and I am much happier with the consistent and predictable results.  The picture below shows the conversion to the fast-on connectors.

You will also note that this shot is from the baggage bulkhead where I have created a connection to the pitch trim wires so that I can complete the wiring tasks without the requirement of attaching the tailcone.

Since the Viking engine uses a different fuel pump assembly than the Rotax, it was not feasible to use the Adele clamp on the fuel flow sender to support the wiring harness. In light of that I made an internally threaded aluminum tube as a standoff to attach an Adele clamp which could support the wiring harness as shown below.

Wiring harnesses proceeds aft through the fuel filter/fuel shutoff valve bay.

Another shot of the wiring harness as it proceeds through seat bottom rib area.

Autopilot!

Today, I received the Autopilot Servo Kit for Skyview, by Dynon.  First order of business was to fabricate the two pushrods.

The 1/4", 28 threads per inch tap was applied after the tubing was reamed out with a #3 drill bit.  The threads were cut to a depth of 1 inch on each end.  Below is a shot of the setup, sans the vice to jig the tube.

The finished pushrods with bearings threaded into place.

Canopy Installation, Part 1

Canopy installation began for me with the countersinking of the two holes for the #10 screws that hold the fixed end of the gas spring as shown below.

Test fit of the #10 machine screw into the countersunk hole.

I am intentionally avoiding step #1 on page 34-02 that calls for enlarging the holes in the ends of the gas spring to 1/4 inch (not a big deal) and 3/8 inch, respectively.  I am quite concerned with the 3/8 inch diameter hole in this high stress, plastic part to the extent that I am deferring this step, pending further research into an alternative approach.

In the meantime, the next step involved drilling and deburing ten holes in the canopy frame followed up by riveting LP4-3 rivets.  In the picture below, the rivets are going in after the prep.

Finished rivets on one of the sides of the canopy frame.
 

 Next, the latch handle stop was positioned and drilled and riveted onto the aft section of the canopy frame.

The next operation involved marking and drilling holes into the forward and aft attach angles....the finished products are shown below.
 

Viking ECU #84 Arrives

After a few months of waiting, Viking delivered the final component of the engine installation in the form of the new second generation ECU or engine control unit....the brain of the engine.  It is a very nice looking box, complete with documentation, as shown below.

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.

Flight Controls, Part 2

Next order of business was to modify the existing control sticks to accommodate the Tosten CS-6 grips I purchased for the project.  Removing the last 6 inches of the stock control stick was the
 plan, which was easily done.  Next the end of the tubing was cleaned up and sanded down to accept the turned aluminum stub which mounts the grip into the stick.  A locking Allen head set screw secures the grip to the stick.

Now the nasty task of stuffing 8 #22 wires down the very narrow control stick.  Over a period of several days, the task was finally accomplished.  The trick that worked for me was to use some nylon string with a small knot (for some added mass) on one end and the application of a vacuum cleaner to draw the pull string down the tube.  It took many tries, but I finally got'er done.  The most trying part was making the passage way over/under/around the bushing where the stick pivots.  There is precious little room for the wires to pass.

In the end, it was all for naught as I deemed that the movement of the wires was too excessive when exiting the stick at the bottom.  In order to remedy this, I unhappily opted to drill an exit hole in the bottom of the goose neck for a much superior method.

I can't say enough good things about the Tosten grips - they are works of art and of fine quality.  The principal of the company, Kevin, is an RV-6 pilot and a great customer advocate!  He wants the purchaser to be happy.  He even re-made my grips when I complained that the leads were a bit too short.  He sent me new ones and did not have me return the originals until I was satisfied.  A+++ for Kevin and his Tosten grips.

Now that I had committed to using two grips with hat switches, the need for protecting against a short circuit situation wherein both pilots simultaneously initiate trim commands, had to be addressed.  After consideration of a manual pilot/co-pilot switch, I decided on the more elaborate relay-interlock system to safeguard the circuit.  I purchased the Ray Allen Rel-2 Servo Relay Deck as shown below, along with its fairly straightforward instructions.  More to come on this topic in the Electrical Wiring blogs.

Another minor dilemma that I faced was the desire to powder coat the flap handle to match the controls sticks.  Unfortunately, my powder coat guy could not match the colors and needed another $30 to order the correct powder on top of the $35 minimum charge.  After consulting VAF, I found some clever guys who were heralding the close color match of some tractor paint!

Sure enough, I made a trip to my local Tractor Supply store and to my pleasant surprise found the $6 rattle can of Ford Light Gray, made by Majic Paint Company.

Following are a couple of shots of the finished product.  You can see the close match between the remnant of the powder coated control stick as compared with the tractor-painted flap handle.  I am quite pleased with the results.

Shot of the flap handle air drying in the makeshift finish kit crate standing-on-end-to-serve-as-a-paint-booth.

The flap handle fork assembly was riveted together with the clevis pin secured with a cotter pin.  The clevis will ride in the detents (machined slots) of the flap detent bracket.

The next shot shows the flap handle tube riveted to the fork with the flap knob pressed temporarily into place.  Also note the spring in the foreground.  It is a lighter version of the spring that shipped with the kit as many builders have opted for a similar change.