Yoke Centerpiece

My yokes came without the plastic centerpieces, and indeed they seem to be getting hard to find.  I saw a Taylorcraft yoke, with centerpiece, on eBay and bought it thinking I could make a copy of the centerpiece.  But when it arrived I saw the plastic was warped and deformed.  So I was faced with making a mold from scratch.

I started with a 3inch styrofoam ball like is used by hobbyists to make Christmas ornaments.  I cut the foam ball in half (Photo 2) on the band saw, sanded the radius slightly flatter on top, and then epoxyed it onto a plywood board.  I cut three sections of broom handle and epoxyed them to the plywood in the position of the yoke spokes.  Photo 3 shows the resulting plug.

After giving the plug 3 coats of wax, I covered it with fiberglass to produce the mold. (Photo 4)  I wanted threaded inserts in the finished part so I made a core for the mold as shown in Photo 5.   The core is a piece of 1/4 plywood cut to fit into the spoke cutouts in the mold.  Three 8-32 screws hold 3 nuts in the correct position in the mold.

The layup procedure is to wet out two layers of glass in the mold, then pour 1/4 inch of resin with finely chopped glass in the bottom of the mold.  Next the core is inserted.  After the resin sets, the 8-32 screws are unscrewed leaving the nuts trapped in the 1/4 inch resin-glass layer.

The parts are removed from the mold, sanded and painted.  The backing pieces receive no nut inserts but are drilled instead.  Use the mold core as a drilling template.  Photo 6

You can trim the edges of the centerpieces with a strip of vinyl electrical tape, then screw them in place on the yokes.  Photo 7

The little aluminum inserts are made by clamping aluminum disks between two steel washers Photo 8, and then hammering the edge down around the washer.  Photo 9 Then the insert (with its decal!) is epoxyed in place on the centerpiece.  Photo 10

Link to Yoke Bearings,  Decals, Fiberglass Molds

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Fuel Gauge

The Taylorcraft fuel gauge is about as simple, light, and reliable as can be made.  It is simply a cork on a rod that sicks up through the fuel cap directly in front of the windshield.  It's identical to the J-3 Cub fuel gauge.  They are expensive to buy, but cheap and easy to make. ( Photo 1)

The original unit (Photo 2) had a couple of small design flaws, which we will correct on our new gauge.  First, the cork is literally a cork like comes out of wine bottle.  The cork (1 1/2 corks really) was coated with shellac to make it last longer, but when exposed to modern ethanol blend fuels they will quickly fall apart.  The solution is to use a synthetic fuel float designed for modern fuels.  They are available from Synder Antique Auto Parts as the Ford Model A fuel float.  You need two.  They cost $4 each.

The second problem with the original fuel gauge is the fuel cap itself.  The original had a cork gasket that, again, will deteriorate when exposed to modern fuel.  And the original caps are prone to rust quickly.  The solution is to make your fuel gauge/cap out of a tractor gas cap.  Tractor caps ($6) are designed for use with ethanol blend fuels and have an excellent gasket.  We can keep the cap from rusting by sandblasting and painting it with epoxy primer.

So, gather your parts.  Two Model A fuel floats, a tractor gas cap, 2 inches of 1/4" copper tube, and two #4 washers.  You'll also need a stainless steel welding rod, 3/32 diameter ($2) and at least 16" long.

Solder (silver solder or braze) one washer on the welding rod about 3 1/2 inches from one end.  Install the fuel floats and then solder the other washer on the end of the rod leaving a 1/4" gap between the washer and the now-trapped floats.  A little trick to keep from melting the floats when soldering the washer onto the rod: cut a 2" circle out of poster board, poke a hole into the center of the circle and then soak the poster board disk in water for a minute.  Push the wet disk onto the rod so it rests against the float and protects it from the heat.  When done soldering, simply cut the paper disk away. (Photo 3)

The fuel cap is prepared just like wing tank caps.  (See the "Fuel Caps" entry).  The difference is that the copper tube is only 2" long, with about 1" extending above the cap.  Blast and paint the cap.  Install it on the rod, check rod length in your tank, and then cut to length and bend the end of the rod. (Photo 4)

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Link to Fuel Caps,  Fuel Tank

Documentation, Organization

I use digital photos, but have found them of limited use...I seem to always take the  photo from the wrong angle and often I can't find the photo I want when I need it.

I keep a disassembly log that includes drawings and notes to myself.  My log is an ordinary school notebook.  (Photo 1)

I use a clip board to keep a running list of the parts I'm going to need.  I replace all AN hardware so the list gets rather long and complex.  As my budget permits, I order supplies from Aircraft Spruce and cross them off the list.

I label parts with masking tape and a sharpie marker.  I always label up, down, fore, aft, etc. so I can get the parts back in the right position.  (Photo 2)

I use 3X5 cards to schedule tasks ("Blast and Paint Gear Vees" for example).  I arrange the cards in order and post them on a project board on the wall of my shop.  (Photo 3) As I complete a task, I take the card off the project board and gleefully toss it in the trash.

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Fairleads

Cable fairleads guide the control cables.  There are 10 of them in the T-Craft fuselage.  The original fairlead is a simple plastic tube with two retainer rings.  It is simple and light but is made of phenolic and is no longer available.

The Piper fairlead is readily available, is made of nylon, and is split so it can be installed with the cables already in place.  The problem with a Piper fairlead is that it is longer than the T-Craft fairlead and slightly smaller in diameter.  See the drawing in Photo 1 for a comparison.

An acceptable substitute fairlead is available from Aircraft Spruce.  It is called a "short fairlead segment" and is not shown in their catalog, so go to their website and search for the part number 40071-00.  Each segment is half of a fairlead so you'll have to order 2 segments for each fairlead (20 segments make 10 fairleads). (Photo 2)

The length of the short fairlead segment is exactly right for a Taylorcraft but the diameter is about 1/16" too small.  If you wrap 2 or 3 turns of ordinary masking tape around the fairlead during installation the diameter will be just right.  The masking tape also makes installation much easier as it holds the parts in position while you put on the retainer ring. 

A 3/4 inch snap ring can be used as a retainer or simply use the Aircraft Spruce retainer rings by slipping them right over the masking tape.  (Photo 3)

Cost? $.83 each for two segments and $.27 for a retainer, or $1.93 per fairlead.  Total of just $19.30 to do the entire airplane!

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Link to Fairleads, Phenolic

Gear Return Bumpers

Gear bumpers cushion the return of the gear after it flexes the bungees.  The originals are no longer available, but a much improved copy can be made from an axe handle protector.  One end of the axe handle protector is cut off (Photo 1).  A bandsaw does the job in a minute.

Axe handle protectors are available from Ace hardware stores for a few dollars.  (or ultimatetoolgroup.com)  Size HS-3 works great.  (Photo 2) You'll need two of them.

After cutting off one end of the handle protector, drill two holes about 1/8" diameter completely through.  Make the holes 2" apart and about 3/4" below the cut off end.  Push the bumper onto the fuselage frame in the gear return position and secure it with safety wire. (Photo 3)

Link to  Brakes,   Tires,   Wheel Pants

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Fuel caps

Caps for wing tanks need a special positive pressure vent.  The top of the wing is, of course, a low pressure area and without a positive pressure vent the tank will not drain in flight.  The positive pressure vent is simply a tube that faces into the airstream. (Photo 1)

These caps can be purchased, but they are quite expensive.  Make your own for just a few dollars.  Start with a tractor gas cap, the kind used on a Bobcat loader is just right, it has a neoprene gasket that is easy to remove without damage.  You'll also need 4 inches or so of 1/4 inch copper tube.

Make a cap adapter for your vice.  I made mine out of two hardwood blocks.  Bandsaw the cap radius into both blocks, and cover the "jaws" with rubber from an old bicycle inner tube.  (Photo 2)

Clamp the cap in the vice upside down, drill a small hole (pilot hole) through the center of the spring.  Then use a carbide tip drill bit to drill a 1/4 inch hole through the spring, but not all the way through the cap.  You'll need a carbide tip drill (cement drill) because the spring is hardened steel and a regular drill bit won't do it.

Flip the cap back right side up and drill a 1/4 inch hole in the top of the cap with an ordinary drill bit.  Use the pilot hole for alignment.

Then insert the copper tube and solder it in place.  Use silver solder.  (Photo 3)  The cap has 2 little vent holes on the inside that won't be needed anymore so flip the cap back upside down and solder closed the little vents in there.

Sand or sandblast, paint with white epoxy primer and reinstall the gasket.  Install the cap on the tank filler neck, then bend the tube in the airstream direction (forward).  I use a little homemade fiberglass bending tool (Photo 4), but a spring bender works good too.  Don't try to just bend the tube by hand...it'll kink.  Finally paint your fuel cap red.

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Link to Fuel Gauge, Fuel Tank

 

Tire mounting

Mounting aircraft tires is much easier than automotive tires.  The wheels are split in two halves, then bolted together inside the tire.

Use tire talc...or just as good is ordinary baby talc or bath talc.  Smells nice too.  Sprinkle some on the tube and the wheel innerds.

Slightly inflate the tube inside the tire, insert the outside wheel half, push the valve stem through the hole, then install the inner wheel half and bolt them together.

Caution: don't pinch the tube between the wheel halves. 

Many wheels have a torque specification.  Shinn wheels do not.  Tighten the bolts evenly snug.

The valve stem will try to push back into the wheel when you try to inflate the tire.  Secure it with a thin nut, or use one of those bicycle pumps that clamps onto the stem.

Inflate to pressure spec (20psi for T-Craft), then let it rest overnight and check again.

Link to  Brakes,  Gear Return Bumpers,   Wheel Pants

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