Postponement

I am sure that you, my faithful readers, have noted a slowing in progress.  It is not due to a lack of interest or dedication.  I still love getting out to the shop and fabricating parts.

But family obligations have increased in recent months and have seriously impinged on the time and, to some extent, the money I have to devote to this project.

I am at a decision point.  The next steps involve purchasing some expensive materials and parts, and engaging in intense construction activities. I do not have the time available to devote the time necessary for the next steps. So those expensive parts and materials would have to lay around for an indefinite period of time.

Taking all of that together, I have had to make the painful decision to put this project on indefinite hold. I will be carefully storing the parts I have fabricated so far in hopes that the project can be restarted sometime in the future.

I will also not delete this blog in hopes that its contents can be useful to other builders and that perhaps, one day, the project can be revived.

Thanks for reading.

Then There Were Two

The rear aileron pulley brackets are finished.

Well, almost.  I need to decide what color I am going to paint internal wing fittings.  Probably white.  And the hardware store bolts need to be replaced with aviation hardware.  The hardware is still on back order.

The next fittings will be the wing attach brackets.

In case you didn't pick up on it, I have switched back from the Cuby to the Wag-a-Bond.  Why?  Very simply, my shop is not long enough to fabricate the Cuby fuselage.

I have also decided to build the engine from Corvair components.  The Corvair based aero engines have proved to be capable and reliable and well suited to the Wag-a-Bond.  Check out:

http://www.flycorvair.com

Some very good stuff.

Two Forward, One Back

Here is a photo of the parts, at this point, for the second upper aileron pulley:

You may be wondering why it appears that there are two top strap blanks, one longer than the other.

The answer is that I did not have my head fully in the game.  The shorter one was cut out first.  It will end up in the trash.  The top strap is supposed to measure 2.70" between the hole (not yet drilled) centers.  Not paying full attention, I fabricated the first attempt 2.70" long overall.

The holes will be drilled in the longer, and correct length, top strap after bending. It is advisable to drill holes after bending to be sure the holes end up in the correct location.  Bending can introduce errors in the hole locations if the holes are drilled before bending.

Not only is this sound advice to be found on the EAA website, I can personally attest to its wisdom. How do I learn these things?

One other interesting point on these parts. It took me two months to fabricate the first top aileron pulley bracket.  If I hadn't made the measurement mistake, the second one would have taken a little over an hour. As it stands, the assembly is between 1/2 and 3/4's of an hour from completion.

More Pulleys

So I started fabricating the top/rear aileron pulley brackets.  At first my attempts were centered around the pulley choice from the previous post.  It didn't work very well.

Then I remembered a comment by internet contact, Mike Finney (who just happened to take Reserve Grand Champion, Plans Built at Oshkosh last year), about roller bearing pulleys.

I went shopping again and found the roller bearing pulleys.  Here is one alongside the aluminum pulley with the bushing.

As you can see, the roller bearing pulley is a phenolic pulley, but with a sealed roller bearing.  This is a very nice pulley and really makes sense as the center component of the aileron pulley assembly.

Here are the component parts of the pulley assembly.

The hardware-store nut and bolt will be replaced with proper AN hardware when my back-ordered shipment arrives.  The bracket and the top strap are fabricated from .050" 4130 steel.

And here is the completed (well, almost) assembly.

The basic concept and design comes from another internet contact, Marty Feehan.  He was kind enough to send me photos and drawings. You can see how this assembly mounts in the previous post "A Brief Hiatus".

The bracket and top strap need final cleanup, priming and painting.  I have one more of these to build.

Pulleys

Which pulley would you use?

The pulley on the right is manufactured exactly according to Piper specifications and is certified for use on Piper aircraft from the J-3 Cub to the PA-22-135 Tri-Pacer.  Is is manufactured from phenolic and the grip (the unthreaded part of the bolt) on the bolt that secures the pulley in the bracket serves as the shaft on which the pulley is mounted.

The pulley on the left is an after-market product (Javron, Inc.).  It is CNC machined to the correct dimensions from aircraft grade aluminum, anodized, and fitted with a bushing as the main bearing surface. It is also certified for use in Piper airplanes from the J-3 Cub to the Tri-Pacer. 

Yeah. Me too.  There are plenty of Piper aircraft flying around today that are fitted with the phenolic pulley, but the aluminum pulley, with the bushing, gives me a much higher level of confidence.

These pulleys are aft aileron pulleys.  More details as I get the brackets fabricated.

Aileron Hinges

The Aileron hinges are finished!  What with learning new skills, relearning old skills and acquiring some new tools, this project has taken since October.

If you are in a hurry to fly, scratch building an airplane is not the way to do it.  I love the process, and I am having a lot of fun, but I have a flying airplane up in the hangar. 

This photo came out a little dark, but that's OK.  It just documents the existence of six aileron hinges waiting for their coat of yellow paint.

A Short Hiatus

There has been a bit of a gap in the work because I got side-tracked by the idea of trading my Cessna 150 for a Piper Pacer project.

After responding to one offer in detail, I decided not only to reject that offer, but to reject the idea.  The big problem is that I would be without a flying airplane for an indefinite amount of time.  That is simply unacceptable.

One piece of very good news is that during the time I was exploring the Pacer possibility, one of the folks on the Wag Builders forum showed me a much better aileron pulley arrangement.  Instead of a small bracket welded to the aileron hinge, he has devised a pulley bracket that shares the top hinge bolt on the front side of the rear spare with aileron hinge.

This is much easier to fabricate and aligns the cable with the actuating horn much better.  These photo are from my friend's shop.  I will fabricate these brackets (I need two) after I complete the last of the aileron hinges.

Pulley Post

OK!  Back to airplane parts.  The photo below is the post that will go on top of one of the aileron hinges to support an aileron pulley bracket.

I have been dreading these parts. There are two of them, one for each wing. I know it doesn't look all that complex, but that angle has to be exactly 10 degrees.  The lower part of the post has not been trimmed to length yet.  It will be about 5/16" long (it is currently about 2-1/4") when finished.

Pretty good looking weld, too.

The bracket welds onto the "upper" end of the angled part. The idea is to mount the pulley at a 10 degree angle so that it clears the hinge.  I will fabricate and install the bracket after I have this post welded onto the hinge.

Getting that weld lined up and held in place will be the next challenge.

What's This!!!

This doesn't look like an aircraft part!!!

And it is not.

My wife gave me a weather station for Christmas.  One of the challenges has been to find a place to put the rain gauge and figure out a way to mount it.  It wants to be out in the open, but it requires batteries, so it needs to be accessible.

I decided the best place to mount it would be on a fence post.  So today I fabricated this bracket.

Yes, I did some airplane fabrication, too. 

Cutting Sheet Steel

One of the aspects of building a rag-and-tube airplane is that the primary structural material is 4130 steel, commonly called "chrome-moly".  It is tough stuff and cutting out sheet steel parts can be a challenge.

I acquired the inexpensive (OK, cheap) Harbor Freight power hack saw.

This saw can be used vertically or horizontally.  They recommend that it be used horizontally for metal shapes, like tubing, angle, etc.  I started out switching it back and forth, using the vertical for sheet metal and horizontal for shapes, mostly tubing.

However, I found it just as fast, and almost as easy, to cut the thin wall shapes we use in airplane construction with a hand hack saw and just leave the powered saw in the vertical position.  To lower the saw to the horizontal position, the table must be removed.  Though it is not a big task, it gets bothersome enough to make hand sawing thin-wall tubing attractive.

I am quite happy with this little saw, with a couple of caveats.  The first being the blade that comes with the saw.  It may work fine on carbon steels and non-ferrous metals, but it rapidly  wore out on 4130.  I purchased the Harbor Freight bi-metalic blade with 18 teeth per inch (TPI).  The original blade was a bit more coarse at 14 TPI.  The 18 TPI works much better. If this blade wears out rapidly I will go to Starrett or one of the other higher end blades.

When cutting and drilling steel, always make sure you have adequate lubrication. A good grade cutting oil will help your tools last a lot longer.  Yes, it gets things messy. Live with it.

Another caveat is that the gullet around the small table used in the vertical position is pretty large, abut an inch and half square. With that big a gullet the blade had a tendency to grab the work piece, especially delicate cuts near an edge, and bend the metal down, quite violently.

So I fitted this chunk of wood over the table.

It is held in place with a couple of 8-32 machine screws and nuts. It works just fine, allowing me to cut very fine shapes without the piece disappearing into the inner workings of the saw, or grabbing the piece and cutting my hands to shreds.

Which reminds me of a safety note.  Always wear stout gloves and face protection when working around machinery, particularly when working on small pieces from light gauge metal.
 

Ancient Time Honored Skills

First, just to prove that progress IS being made, here are the three completed aileron hinges.

Three more to go.

But what I really want to talk about today is, what seems to be, the lost art of sharpening drill bits.  This interest was brought on because somehow I have managed to misplace the drill point gauge that I have had since I don't remember when.  At least 40 years.

I grew up believing that, if you wanted to drill holes in things, you needed a small assortment of tools.  The first being some means of turning the drill bit, such as a hand drill or drill press. Back in those days you usually had an "egg beater" style of hand drill, a 1/4" electric drill, and, if really affluent, a drill press.  Obviously, you needed drill bits, too.

But nothing stays sharp forever, so two other tools, a bench grinder and a drill point gauge are necessary.  As observed above, I lost my old faithful drill point gauge somewhere along the way. 

Being the naive type, I trotted down to my local hardware store, which has a very fine inventory, and got blank looks when I asked for a drill point gauge.  Nobody, but nobody, in the store had heard of such a thing and had never heard of anyone sharpening drill bits.  Everybody just assumed that dull bits got thrown away and new ones purchased.  Unbelievable.

On a hunch, I stopped at the local NAPA on my way home.  The gentleman at the counter (with gray hair) at least had heard of a drill point gauge.  However, they did not have one in stock.  The best he could do was offer to sell me a dedicated (made in China) drill sharpening machine at something well north of $100.  For sharpening drill bits?  Give me a break!

I finally found a drill point gauge at L.G. Isaacson.  But first, a brief description on how drill bits are sharpened.  A good bit has four characteristics:

1.   It is straight. That is set at the factory and you can't change it.
2.   The cutting lips are sharp and are raked back from the point at 59 degrees.
3.   The bit slopes back from the cutting lips to clear chips.
4.   The point, where the two cutting lips come together, is centered.

A bit gets dull when the cutting lips are no longer sharp. The process of returning them to a good sharp condition is, with a little practice, very easy.

You hold the bit, as shown below,  with the cutting lips at a 59 degree angle to the wheel, parallel to the floor.

Note that I have drawn a line, with a Sharpie, at a 59 degree angle to help me keep the bit aligned properly.  Just touch the bit to the wheel and then give it a slight clockwise twist while lowering the far end of the bit just a tiny little bit. Flip the bit over and do the same to the other side.

If you did it correctly, and evenly, your lips will be sharp, the rake will be correct, the angle of the lips will be 59 degrees, and the point will be centered.  How do you know if you got it right?

Why with the point gauge, of course.

Here you can see how the point gauge is used. The angle on this bit is slightly off, so it needs to go back to the grinder.  To check the centering of the point, just compare the two sides of the drill to the number etched on the gauge.  You will note that the point on this bit aligns with the "5" line on the gauge.  The other side should do the same (it does).

The final test is to drill into a piece of mild steel. At the right speed and feed rate you should get nice curly chips.  If not, back to the grinder.

See, that is not so difficult.  And you get years of use out of a drill bit instead of just a few holes.

And Then There were Three

Today's task was to finish the third aileron hinge.  There is one more "easy" one.  Then there are two more that start out exactly like the first four, but mount pulley brackets that have to be precisely positioned.

The theme for the next little while is just slogging through the fabrication of aileron hinges.

Another Hinge!

You can expect the above title to be repeated in the next few weeks.  I have one aileron hinge complete, one finished except for primer, and a third started.  There are a total of six.  Two of which are complicated by carrying the aileron pulley brackets.  I will build those last.

There won't be many photos.  They would just be highly repetitive.

Ran out to the hardware store today to pick up a new drill gauge.  I don't know what happened to the one that I purchased sometime in the 1970's.  I was amazed at the blank looks I received. Nobody at the local hardware store (and this is a mill town fer cryin' out loud) had any idea what I was talking about.  The best the local NAPA could do, after receiving a long explanation as to what a drill gauge is and how its used,  was offer to sell me a "Drill Doctor" electric bit sharpener for $100.  Really?

Has the simple, but essential, art of drill bit sharpening been lost?

A Tale of Two Helmets

You will recall from an earlier post that I was having some difficulty with my welding helmet.  It turned out not to be the helmet's fault.

Welding helmets come in a variety of styles, features and costs.  You can get an auto-darkening helmet for as little as $40.  I looked at one today that was over $500.  One needs to shop carefully.

The helmet on the left is the first welding helmet I purchased.  It was advertised as being suitable for TIG and, if I recall, was about $80.  It worked fine while I was learning to weld.  Most of what I was practicing with was 1/8" mild steel. In the learning process you start with thicker materials and work down. When I first started welding actual airplane parts I started having trouble with it "flashing" from dark to clear and back again.  Very annoying and not a good way to protect my eyesight.

It turns out that one of the specifications that affect the price of a helmet is how sensitive it is to the TIG arc.  That sensitivity is expressed in amps, as the amperage level that one is welding at determines the size and brightness of the arc.  The helmet on the left has a minimum sensitivity of 40 amps.  In welding aircraft parts one rarely applies more than 30 amps.  Therefore, the flashing. But the helmet would work fine if you are working on heavier materials, such as farm equipment.

The helmet on the right is the new helmet.  It is a Miller Digital Pro and it is about the minimum helmet I would acquire if I am working on airplane parts.  It has three sensors and is sensitive to TIG arcs down to 5 amps.  The kicker is that this helmet set me back about $250.

I really wanted a black one.  I am not that fond of the graphics, which are pretty tame here.  They can get quite wild.  But the local shop didn't have a black one and knocked a considerable amount of money off their tag price if I would take this one, the floor model.  I like to buy local if I can, and this worked for me.  At least it is not painted up like skull.

THE HELMET PROTECTS YOUR EYESIGHT. Get as much helmet as you need.  If you are working on heavier materials, or, at least materials that are not as light as what we work with building airplane parts, the $80 helmet would probably work just fine.  If you are working on lighter materials, as I am sure most of the folks visiting this site are doing or planning on, you are going to have to tighten your belt and loosen your wallet.

Hinge

Here is the completed aileron hinge:

The paint is a primer coat.  I haven't decided what color I am going to paint fittings.  Probably yellow.

The welding is gas.  Why you ask.?  Because it appeared that my welding helmet was still not functioning properly. So I did all the welding with oxy/acetylene, which can be done with simple welding goggles.  The welds are kind of ugly.  They are strong, just ugly.

I finally managed to talk to somebody at the distributor for my helmet.  It would have been "manufacturer" in the old days, but this helmet, as practically everything else, is made in China.  I explained the problem and what I had done to try and fix it.  They figured, given what I had done, that the helmet should work just fine provided I was welding at anything above 40 amps.  40 amps? This is aircraft welding.  I am rarely above 30 amps!

The upshot...my helmet is working just fine, it is simply the wrong helmet. What I really need is a helmet that will work down to about 5 amps, or maybe even less.  You guessed it. The 5-amp helmets are generally the top-of-the-line helmets.  The folks who make my helmet don't even offer one.  They recommended that I look at a Miller helmet.  Take the $80 I spent on my current helmet and multiply that by about 3.75.

Though I haven't actually run the numbers, I am beginning to get the feeling that I have spent more money on learning things than actually fabricating parts for the airplane.

The Saga of the Sons-in-Law

To begin with, the previously reported progress was a bit premature. I discovered that the aileron hinge I thought was complete was fabricated incorrectly.  I welded the bushing into the end of the tube and trimmed the tube around it.

It is not supposed to be that way.  As we go through today's post, I will demonstrate the way it is supposed to be installed.

Aside from mistakes resulting from mis-reading the plans, there have been production problems.  Drilling 3/8" holes, perfectly aligned, in the tubing proved to be a very challenging task.  There is a video on the EAA site that shows a gentlemen fabricating a v-block out of a couple of pieces of angle iron and then duct taping that to a piece of wood.  I believe this approach would work fine when drilling aluminum tubing, which is the case in the video.  It simply does not work when trying to drill steel tubing.

I discussed the problem with one of my sons-in-law who is an industrial engineer.  He described the method they use in his company.  It involves a basic v-block with a bushing attached to it to guide the drill bit.

I looked into this arrangement and found that it either required a rather substantial outlay of cash, or machine tools to which I have no access.

But applying the principal of keeping things rigid, I developed the following process, beginning with the acquisition of a pair of v-blocks, which took an inordinate amount of time getting here because they were coming from New Jersey at the height of the winter storm that hit most of the country.

Some of the photos I took today did not come out very well, so you will have to settle for narrative for the time being for some of the steps.  In some cases I will use the fuzzy photos.

The first step is to center the v-blocks in the drill press.  This is accomplished using an appropriately sized drill bit run into the center of the "V" and securing the vise.

In order to keep things rigid, and avoid a drill bit wandering around center before getting a grip, I used a center drill swiped from my Unimat (a small model makers lathe) to drill a pilot hole.  The center bit is designed to drill a countersunk hole in the end center of a piece of round stock for turning on the lathe.  It is a small bit with a fat body so that it does not flex and wander around.  I apologize for the fuzzy photo.

This pilot hole is centered 3/8" from the end of the tube to correspond to the outside diameter of the bushing.  Why would I choose that dimension?  Continue with the saga and you shall see.

The next step, without disturbing the alignment, is to enlarge the hole with 1/4" bit, which corresponds to the guide point on my step drill.

Once the top hole is drilled the bit is advanced to drill the bottom hole.  This is the place I took a bit of a chance.  The 1/4" bit is chucked in the drill press as short as possible to reduce flex, plus, I was hoping that the upper hole would help serve as a guide and steady rest for drilling the bottom hole.  It worked.  The top and bottom holes ended up exactly aligned.

After drilling the 1/4" hole I replaced the drill bit with the step bit.

And enlarged the top hole to the required 3/8".  I then flipped the tubing over, aligned the bottom hole (now on top) using the guide portion of the step bit, re-clamped it in the v-block, and enlarged the bottom hole.

The holes ended up perfectly aligned.  It seems like a lot of steps, but it really doesn't take very long.

The next step is to draw some lines extending the outside diameter of the hole to the end of the tube. What did we ever do before Sharpies?

And cutting out a slot whose width corresponds to the outside diameter of the bushing.

The reason this is done is because once the bushing is tacked into place, the ends of the tube will be heated up and bent around the bushing.  Below is the bushing ready to be tack welded in place.  It is cut long to facilitate welding.  Once welded into place it will be trimmed back to correspond to the outside diameter of the tubing.

And here comes the contribution of the second son-in-law.  As I was attempting to tack the bushing, my welding helmet would not work properly.  I have a self-darkening helmet. It darkened as soon as I struck the arc, and then promptly went back to clear!  It would oscillate back and forth.  I obviously could not use it that way and hope to hang onto my eyesight.

In discussions with another son-in-law, who happened to be visiting, he pointed out that the helmet is solar powered and perhaps all it needed was some recharging.  We shall see.  I have the helmet sitting in a window so it should have an opportunity to recharge while I am at church tomorrow.

Not wanting to abandon all progress, I tacked the bushing in using oxy/acetylene.  After I bent the ends around the bushing, I went ahead and finished up welding the bushing in place with the gas.

The above is the bushing finish welded, ground down to the proper length and reamed 0.250"

I had previously fabricated the brace, but I didn't have a useable bracket.  So I needed to make one of those up.  Here is the blank set up in my cheapy little Harbor Freight brake, which works quite well if you don't push it too hard.

Checking the first bend.

Set up for the second bend.

Checking the second bend.

And here are all the parts in the jig ready for tack welding.  We will see if charging the helmet works. I would rather tack this up using the TIG than the gas.

More as it happens.  Hopefully I am on the road to steady progress.