Monday, October 27, 2014

Brake Pedal Progress

 I made a wood block, from a piece of 4x4, for a jig to hold the cable clip in position for welding to the rudder pedal, shaped like the Styrofoam mock up.  The end is cut tipping forward 28 degrees.  The side leans in 13 degrees.  The clip then twists 15 degrees.

 I carved some clearance around the weld area and clamped the clip to the block.  The pedal is clamped to the block with a stick of wood.

The block is made so one pedal is made with the clip at one end and the other end makes the opposite pedal.

 It was easy to weld with the joint very accessible.
 The bearing tubes for the rudder pedals are welded to the back of the rudder bar, parallel to the rudder bar pivot bearing, but rotated 50 degrees.

I made a block with a notch to hold the bearing in the correct position.  I clamped on a block of wood to align it with the bottom of the rudder bar.

With a cross ways block of wood I clamped the whole thing tight to the rudder bar.  It worked OK but you could only tack one side, in 2 places, then remove the block tack the other side and weld the joint.

 The block got scorched pretty good but wasn't damaged too much to weld the opposite bearing.
 All the blocks got scorched but they worked fine.
 The rudder pedals are finally in the bearings, we're getting there.
 Because some of the welds require welding on or near a previous weld so I clean each weld before making the next one.  The next parts to weld are the gussets on each pedal bearing and a piece of tubing to act as a return stop for each pedal.

 The Pivot Bearing also get a gusset which is not needed on the standard rudder bar.
 After the pedals are installed in the bearings the brace which supports the cable clip and be welded to the clip.  It just fits over the short end of the rudder pedal with a cotter pin to secure it.

 The cotter pin hole is drilled 3/32" dia., 3/16" from the end of the short leg of the pedal.  The hole is perpendicular to the plane of the pedal "L".  I marked 3/16" from the end of the tube with a pencil then burnished a line on the top and bottom of the tube.  Just rest a straight edge on one tube and gently rub it on the other tube to burnish a center line.  By center punching a hole on each side of the tube I end up with a hole straight through the tube.
I started the hole by drilling a pilot hole with the tip of a 3/16" center drill.  With a pilot hole on each side the 3/32" hole can be drilled straight through.

Friday, October 24, 2014

Standard Rudder Bar and Front Cockpit Pedestal Welded

 The last parts to weld to the standard rudder bar for my plane are the clips which hold the rudder cable from sliding along the rudder bar.  They are just small pieces of 0.095" steel with a hole drilled for a cotter pin.

I used this hole with a small spacer of 3/16" tubing and a cotter pin to hold the parts spaced and aligned parallel to each other.  A piece of safety wire twisted tight worked great to hold them while welding.  I found the 0.032" wire was easily melted with a stray torch, 0.040" wire worked better.

The cotter pin and spacers were easily removed after welding.

 I started welding the front cockpit Rudder Bar Pedestal by tacking the ring to the main tube in 3 places.  I didn't want the tack welds to interfere with the diagonal tubes.  While tacking the ring I supported it with a piece of tubing to hold it the correct distance from the end of the tube.

I drilled locating holes in a piece of plywood and bolted the diagonal tubes and base plate to it with washers to space it up about 1/2" from the wood.  The wood still got scorched tacking the base plate to the main tube.

I welded as much of the cluster as I could reach with it bolted down then removed the bolts, finished the cluster, and welded the base.

 With it welded the cotter pin hole in the main tube and top ring were drilled.  It's ready for paint.

Very cool to have a nice new assembly.  I'll use the new bar in the rear (pilot) cockpit and move the old one to the front (passenger) cockpit.

Now I need to finish John's Heel Brake Rudder Bar.

Tuesday, October 21, 2014

Brake Pedal Arm Position

 The brake cable, or in John's case the brake cylinder is actuated by an arm (with small hole) welded to the brake pedal.  It is supported by the brace which is welded to the arm and fits over the short end of the brake pedal.  A cotter pin keeps the brace from sliding off the pedal tube.

The problem was how to hold this arm in the correct position while welding it to the pedal.

 I realized I could use a block of wood to hold the arm in place.  I've mocked it up from a piece of Styrofoam to see how to make it.

The arm tips forward 28 degrees.

It stands up at 77 degrees, or if you will, tips in 13 degrees.

Looking from the top it twists 15 degrees from the center line of the long tube.

 Here is the result of all those angles.  I think a wood block will work.  I'll cut it away near the weld area.  Even if it gets badly scorched it won't matter because I have to make separate block for each pedal to get a left and a right.

The brace gets welded on after the pedal is installed on the rudder bar.

Thursday, October 16, 2014

Welding Rudder Bar

 The brake pedal tubes form an angle of 82 degrees to hold them aligned while welding I made a fixture from a piece of 3/16" steel and some hose clamps.  I drilled and filed holes for the clamps.  I found that having the clamps tight to the fixture prevented the tubes from moving and made it easier to align them.

I left a 1/32" gap between the tubes. I thing about 3/64" would have made welding easier with 0.065" wall tubes.

 The little tabs at the end of the brake pedals are the heel stops.  They're made form 0.065" steel and are basically 3/4 of a round slug.
 I found an easy way to hold the Safety Stops on the ends of the Rudder Bar.  I just used a piece of 0.032" safety wire to hold them until I had tacked them on.

 To hold the Pivot Bearing square to the Rudder Bar I used the fixture plate from the Brake Pedals and bolted the Bearing Tube to it.  I put 1/4" spacers under the Rudder Bar and clamped it to the plate to hold everything while I welded it.  I was able to weld about 3/4 of the way around before I had to remove the fixture to get at the area it blocked.

To hold the Bearing Support tubes in place while I tacked them to the bearing I placed a small magnet at each end on the Rudder Bar.  Once they were tacked to the bearing I removed the magnets and tacked them to the bar and finished the welds.  We're getting there.

Tuesday, October 7, 2014

Rudder Bar Parts Finished

 The only complex part is the diagonal brace for the Clip (bracket) which the brake cable attaches to.  John is planning to install hydraulic brakes.  I've drawn both brackets and drilled the hole 1/2", my largest drill size.  The big hole fits loosely over the end of the small end of the "L" shaped brake pedal tube (5/8").  I drilled the holes before using the band saw to cut to the parts because it's easier to hold a bigger piece of metal.

You can see in the picture I scribed a line for the 11/16" hole.
 With the parts cut out,  I clamped them in the vise and used a rat tail file to open the holes to the line.  By using as large a file as will fit it's easier to get a round hole.

After filing I used a 5/8" sanding drum to smooth the holes and then deburred the edges.

 There is a drawing which says to bend the end with the hole 55 degrees and one which says 60 degrees.  I chose 60 degrees since it was the later drawing and I assume they simply corrected an error in the original design, who knows.  I could have drawn this all out in 3D CAD but decided it was quicker to make new parts if I'm wrong.

I made a form block for the bend from a piece of Oak.  I gripped the hole end because of the very short space from the hole to the bend.  This probably would have worked better with a steel block to grip that short section better.

 For the long bend I made a steel block by grinding a 3 degree bevel on a piece of 1/2" x 1" bar stock and the putting a 1/16" radius on the corner. The ends of the block had to be cut to fit the angle of the end with the hole.  Because this is 0.065" steel, I had to support the block in the vice with a piece of wood.  As with other parts I used a piece of hardwood to hammer the bend.
 Here are all the parts for the Brake Pedal Rudder Bar.  The are a few pieces for the cable pulley which I did not make because John will be using hydraulic brakes.
 The pedal parts.  The drawing says to weld the diagonal brace to the bracket after the pedal is installed on the rudder bar.  The end with the hole slips over the tube and is held in place with a cotter pin.

The partial washers at the end of the pedal are to keep the heel from sliding off.
I found a later drawing which show that I formed the bullet end the way they did it at the factory, very cool.
 This photo shows the pedal bearing tube and it's brace bracket.  The small tube to the left of it is a stop for the pedal.  It's not clear from the drawing how it mounts.  I assume it will be obvious once the pedal is welded on.
This is the Rudder Bar Pivot Bearing.  Not only is it a heavier tube than the standard bearing it also gets an extra brace made from 0.065" sheet steel.

The next task is to weld all these.