Friday, October 31, 2014

35-02 Tires & Wheels

This page took a couple of days, but it was fun because I was working in a new domain.  Steps 1 & 2 were straight forward:  drill 3/8” into the firewall and engine mounts and attach the engine standoff.  On the other hand, drilling though stainless steel and then steel was not easy.  Rather make the jump from 1/4” to 3/8” in one pass, I staged up the drilling in 3 steps.

IMG 3720

Engine Mount Standoff

With the engine standoff taken care of, I turned my attention to the tires & wheels.  Never worked on these before.  Learned quite a bit!  Specifically, I learned that it’s really easy to get the “front” and “back” confused.  I admit to reassembling and disassembling the 1st wheel several times.  I actually re-assembled it a bit farther than I was supposed to.  i’ll have to take the brake off again when I put it on the plane.  On the other hand, I had watched Walt Erdy, my mechanic for the Cardinal, change a tire so I had previously seen how to use the talc powder, etc.  I was pretty pleased with my progress of assembling the front and both main wheels.

IMG 3721

Main Wheel, outside face


IMG 3722

Main Wheel, inside face, with brake


IMG 3723

Inboard Main Gear Attach Braces

32-08 Flap Actuator, torque tube prep

Again, not a big deal, and thus a highly satisfying page.

IMG 3717

Flap Handle with Actuator Button


IMG 3718

Flaperon Torque Tubes with Spacers

The torque tubes needed to have nylon spacers epoxied in place.  I don’t understand why they have to be #12 drilled where the rivets go, especially since the rivets don’t attach anything.  Weird.  The black and silver gadgets that you see sticking out are allen wrenches that happen to be 1/8” wide.  They are holding pressure on the nylon spacers until the epoxy sets.


BTW, I’m done with this chapter for now.  The next step involves attaching the wings and drilling the matching torque tubes.  Those require the final skins to go on the belly/lateral edge of the fuselage and those require the tail cone to be attached.  On the other hand, it would be much easier to do the match drilling without having to climb into the back of the fuselage when it’s attached.  Oh, well.  I’ll solve that dilemma when I get there.  For now, I can’t do anything with the rudder or stabilator control links since they aren’t anywhere near the fuselage itself.  In other words, I’m on to the gear!

32-07 Flap Handle Actuator

Not much fuss.  It was nice to have some basic metal work, without the complications of cramped small spaces.  It felt fun to realize that I had gone from being afraid of squeezing rivets to discovering that they were therapeutic.



IMG 3716

Flap Handle Detent Bracket Assembly

 Not pictured:  Flap Handle actuator assembly

32-06 Flaperon Pushrods

The flaperon pushrods were fairly easy to build.  It took quite a bit of percussive coercion to install the studded end-caps into the pushrods!  I don’t believe that the rivets added anything to the strength or stability of the assembly because those guys aren’t coming out on their own.  Attaching the pushrods to the mixer was easy.  Attaching the flaperon torque tubes was a bit trickier because of the traditional problem of putting the inside washers into place when you are working with a small, enclosed space.  To make matters worse, the fuel tank is still installed on the R side and I wasn’t able to remove it because the fuselage is too close to the floor to get under it to remove the fittings.  Perseverance is key, and I was eventually able to get everything bolted (and washered) in place.

IMG 3713

Flaperon Pushrods attached to Flaperon Torque Tubes



IMG 3714

Flaperon Pushrods attached to Mixer

32-05 Control Sticks

What a royal pain in the pa-tootie!  It took forever to get this page completed.  The two biggies were my work schedule (lots of unwanted overtime) and the fact that it was not possible for me to fit the ends of the control rod assembly into the forks of the control sticks.  I had the fuselage up on its R side and was working in relative comfort.  Unfortunately, I couldn’t see up into the L seat area because my trifocals have the close vision lenses on the bottom and I can’t crane my neck that high up any more.  I couldn’t see down into the R seat area because..., well, I can’t remember what was in the way, but it was.

The end of the control rods require two steel washers to be interposed in-between the forks of the control sticks.  Try as I might, it wasn’t possible to fit them in.  To make matters worse, at one time I dropped the pushrod assembly from the L side (upper) and it fell all the way through to the R fuselage wall.  In the process, one of the steel washers disappeared and I spent over a week searching for it.  I had reluctantly concluded that it may have been flung free of the aircraft into the garage.  Luckily, I found it when working on the wiring harness re-work, so I no longer have to worry about a loose foreign body floating around in the belly of the beast.

Others on VAF confirmed that this is a problem.  One gentleman said that he had to jury rig a spreading apparatus to open up the forks a bit.  Another guy was able to remove the control sticks, attach the rods and somehow snake the contraptions into place.   I did end up removing the control sticks (and having to rewire the PTT harnesses in the process) and finally got the damn steel washers in place.  I didn’t have to make a Rube Goldberg spreader, but I did use a pair of pliers as spreaders to get the washers in place.  I wasn’t able to snake the stick and rod assembly into the proper place, and even got it stuck to the point that I couldn’t get it back out for half an hour. 

I finally elected to unscrew the control push rode from the bearing on the end, re-install the control stick and then re-thread the rod onto the bearing.  To keep the length “just right” I used superglue on the AN316 jam nut to keep it in place.  After I got everything installed, the sticks weren’t quite parallel.  I locked the mixer in neutral (see pg 32-09) and noted that the R stick was a little too far to the right while the L stick was vertical.  I disconnected the R pushrod from the mixer, backed out the bearing stud by 1 revolution and that brought the stick to vertical nicely.

Last, but not least, I found that the control pushrods rub against the AN365 lock nuts holding down the front control block. They only make contact with the stick full back and full roll (either direction.)  I’m waiting for some low-profile lock nuts to replace the ones currently in the kit.  If that doesn’t fix the interference, I’ll grow more grey hair and figure out something.  I’ll also post a query to VAF to make sure that I didn’t do something wrong.


IMG 3706

Control Stick Push Rods attached to Mixer



IMG 3709

Push Rod connected to fork at bottom of Control Stick

IMG 3711

Push Rod rubbing against lock nut



Addendum:   I discovered why the push rod was too far forward and rubbing against the lock nuts.  I’m not yet used to the way this plane flies, and made an error with the use of the flap control rod. I had pushed the flap control rod all the way down, past the detent for 0° flaps.  This would make flaps slightly reflexed (e.g., negative flap angle) and is not an approved flight configuration, thus the designer had no need to verify that the internal parts would not contact each other.  When the flap handle is pulled up slightly, it pulls the push rods aft just enough to not contact the lock nuts (and makes highly loud “thunk” in the process!)


Thursday, October 23, 2014

32-04 Flap Handle Install


IMG 3701

Flap Handle Blocks

Here’s the “rest of the story” (to quote the late Paul Harvey) from an earlier mistake.  (see the entry for 4/30/14.)  I had placed some nut plates on the wrong side of the medial seat ribs.  I was able to (eventually!) drill out the rivets and place the nut plates on the correct side using the lightening holes for access and the -3 pull rivets instead of the AN426-3’s originally called out.  The only thing I couldn’t do was remove/reverse the dimple for the rivets, so the new rivets were not only not countersunk, but they actually are about .010” proud of the surface.  Today was the day that I had to deal with that discrepancy.

To my great relief, I deduced that the pieces that were going to go against those surfaces were the nylon retention/pivot blocks for the flap handle assembly.  Nylon is a much more forgiving material than steel or even aluminum! I did have to grind the short (pivoting) tube of the flap handle to get the handle assembly (handle and two nylon blocks) to fit in between the seat ribs, but it’s a nice tight fit and has no slop or wobble.  I did have to swear a bit to get the nylon block to get over the lip of the elevated rivet, but once that was accomplished it went easily from there. 

The Book calls for me to able to put a piece of paper between the pivoting tube and the fuel line.  It cryptically states that it’s allowable “bend the fuel line slightly.”  VAF made an old cryptic reference to a wooden tool, but the link was dead so I don’t know what kind of tool they were discussing. No matter—I had been given the clue I needed.  I drilled a 5/8” hole in a piece of plywood and then cut right through the hole.  That then went over the fuel line and was gently wrapped with a  dead-blow hammer to put a slight bend in the fuel line to allow it to clear the flap handle.  The above picture shows the paper slid between the fuel line and the tube to demonstrate no interference.  You can also see the business end of the wooden tool described above.


IMG 3702

Flap Pushrod and Mixer

No drama here.  The (correctly oriented) mixer arms accepted the mixer bell crank and flap pushrod without any difficulty.  Note the drop of orange lacquer denoting a torque wrench was used to correctly set the final torque. (In other words, that I hope to never disassemble this again! :-)

21-04 revisited

Remember a couple of pages ago when I asked if you saw anything funny about the flaperon mixer arm?  Here’s that picture for you to take a look at.


IMG 3681

Flapper Mixer Arm (original)

Note the nut plate on the far end.  We are looking down at the mixer arm and the nut plate is visible on the upper surface.  On the next page, I’m supposed to put a bolt through the upper arm and into the nut plate on the lower arm.  That means that we are looking at an upside down mixer arm.  This is the kind of thing that gives me nightmares about this project.  Here’s a classic example of something that I built incorrectly and is nearly impossible to fix due to multiple overlying / subsequent structures.  It took about half an hour of fiddling before I concluded that there was no way to disassemble and remove the mixer arm intact.

IMG 3690

Mixer Arm, removed in pieces

It was ugly, but I managed to get the thing out by hacking each arm into two pieces.  I have a dremel tool with a flexible extension.  I used a cutting disk and a lot of patience to make a very oblique cut through each arm.  (Next time I’ll hook up the vacuum hose right next to the work and collect the dust and debris as it is made.)

IMG 3699

New Mixer Arm

Here’s the new mixer arm, properly installed.  It actually wasn’t too difficult to slide the pieces into place, but lining up the washers and the work pieces required the assistance of my son working from the underside of the plane and gingerly pushing the bolt forward as I held things in place.  To add insult to injury, we finally got the bolt in place only to discover I had used an AN4-21A instead of the AN4-21, so we had to re-install it again.  Oh, well.  It’s finally in place.   I did take advantage of my situation.  When I had the original piece in (upside down) I noted that it rubbed against the thin shim overlying the electrical wiring.  I took the new lower mixer arm and buffed the edge that is close to the shim to give it about 0.010” clearance.  nice!

Saturday, October 11, 2014

32-02 Brake Lines

We’re into a new chapter!  Flight controls can be divided into 4 systems:  brakes, flaperons, rudder, elevator.  Of these, the 1st two can be completed within the fuselage, but the other two require the tail cone to be installed.  I’ll do what I can in front.  

IMG 3691

Brake Fluid Reservoir

IMG 3695

Brake Lines to Reservoir

Although not pictured, I had the obligatory bit of fun with the installation of the clamp that holds the crossover brake lines in place.  I discovered that I had routed the wiring harness in front of, not behind, the brake lines.  That meant that I had to remove the brake lines from the pilot’s side and put them on the correct side of the wiring harness before I could attach their retention clamp.  Sigh... the joys of doing things for the first time...

31B-23 Aft Pitot Line, System Blocks


This was pretty straightforward.  I pulled the pitot line out of the tail cone and installed into the forward half of the plane, as per plans.  This will require me to re-install it in the tail cone, but that should be doable since it only goes back about 9-12”, to the AHARS unit in the proximal portion of the cone.  I expect it will require a contortionist, but that’s what Nick is for.  :-)


IMG 3681

 Pitot Tube & System Block

By the way.  Do you see the flaperon mixer arm?  Does it look normal to you?  Stay tuned for an update in the next day or so.  (Right now, I’m stuck at work with the schedule from hell, so I may not be able to do any work on the plane and update it for a few days.)

31B-25 Over Rudder Wireway

This guy was conceptually simple, but a royal PIA to install.  It isn’t even very visible in the picture, but if you look close you can see a metal tab (with a punched hole) under the wiring bundle and over the rudder torque tubes.  That little metal tray was inserted over the torque tubes and then held with a screw into a previously placed nut placed.  Well, trying to line up that screw into the nut plate when you can’t see either one, and can’t actually hold/touch the screw, and can’t be in two places at once...  well, you get the idea.  I got lots of creative ideas using an awl, rivet stems, flashlights and (literally) blind luck.   Got it.  Eventually.


IMG 3675

Over Rudder Wireway