Sunday, January 31, 2010

Nothing is really new.... (Part 2)

Seriously, you can just skip over these time-killers until next week when the fuselage kit arrives, but I can't help myself: these really fascinate me:

(Sorry about the duplicate "but then it was discovered" - just try to ignore it)
"If you want a secret to get out, tell one woman or several Senators."

Ha! You'd never get away with that today, and not because you can't make generalizations like that about Senators...

Saturday, January 30, 2010

Nothing is really new....

... especially in politics. The various noises emanating from Washington may seem to us to be orders of magnitude more harsh than those our forebears endured, and I often see lamentations regarding the new-found coarseness of our pundit class, but it seems that perhaps it has always been thus and it is an effect of our contemporaneous close proximity to the issues of today that make it all seem so much more brutal than the past.

As a case in point, I enjoy reading aviation-centric periodicals from the relatively early days of the industry. On a quiet Saturday morning, before the family and pets have arisen from their warm, comfortable beds (and, in the case of the pets, their snug spot on a self-chosen section of floor), I sometimes read a few articles from an Aero Digest from March, 1939. Well, to be perfectly honest, I seldom diver deeper than reading the advertisements and every now and then Googling the address of an old manufacturer to see if the building and/or company has survived the intervening years.

Today I actually read some of the news coming out of DC. I found the tone and some of the familiar names of one of the articles to be interesting. Senatorial politics of the late 30's seem to have been every bit as dog-eat-dog and, well, petty as they are today.

I scanned the article to save myself the trouble of transcribing it:

A Machiavellian spanking?

Oh my! I wonder how the NY Times would phrase that today.

I can't help but note that Sen. McCarran of Nevada seems to have gotten the last laugh:

And then there are the things that we have learned to take for granted. Have you ever considered, for example, the need to advertise ground-breaking technology like the Phillips head screw??

I gotta get me summa those new-fangled screws!

Sunday, January 24, 2010

It ain't all glamourous, this airplane building

The transitive periods that fall between the various well-delimited phases of the building of an airplane are convenient times to fulfill some of the clean-up and preparatory tasks that accompany any prolonged project of this size and complexity. Despite the mundanity of jobs such as the building of work benches, they must be done, and to be perfectly fair, winter days with temperatures in the mid-40s fairly scream to be used in some productive task or another, and why not select a task that furthers the progress towards the ultimate goal while you're at it?

So it was the building of work benches that I selected to fill the morning. A quick trip to Lowes to pick up a handful of 2x4s, the collection of same that I had estimated to be plenty on my last foray having proven to actually be somewhere in the neighborhood of 40% shy of that required, and also some 3" #10 wood screws that I had entirely missed on the list. Lowes is pleasant early in a Sunday morning, and the effusive gratitude from the cash register dude as he saw me actually returning the wood hauling trolley back into its rightful place in the lumber aisle rather than abandoning it to its fate in the great expanse of empty parking lot caused me to wonder if some measure of his faith in the humanity of retail customers had suddenly been restored.

Back in the hangar it was a flood of sawing, the fourteen 2x4s being rendered into collections of smaller lengths. Four lengths of 60" and another four of 57" were slowly joined with various counts of 17.5", 21", 33", and 8.5". Plenty of sawdust to be swept up, and then onto the fabrication of the frames. With two frames done and the next step in the plans to be the attachment of the actual work surface, I had to call it a day. The reason being the weight of a slab of 4'x8'x3/4" MFD, which is an order of magnitude beyond my limited lifting capability.

Still, good progress indeed and a fine use for an unseasonably warm, albeit rainy, day. And there's always the NFL to fill the rest of the day, what with my conscience having been salved with the product of the morning's efforts.

Friday, January 22, 2010

Thinking about a more robust rivet squeezer

Even with the wonderful Cleaveland Tools Main Squeeze, I'm finding #4 rivets to be tiring to squeeze.

I think they have these at Harbor Freight now:

Eh, maybe not.

Thursday, January 21, 2010

Have you ever had that feeling?

That feeling that you've forgotten something? It can happen at the oddest times. You'll be walking towards your departure gate at the airport to board a jet for a vacation and you just can't shake the feeling that something is wrong.

Did I lock the door when we left the house?

Yes, I'm sure I did.

You run through a thousand possible things that could have slipped your mind. Then suddenly it hits you - you aren't carrying the laptop computer that is your ubiquitous travel companion on your normal business related travels.

You know the feeling, right? Well, keep it in mind for a few minutes.

After a couple of days out of the shop, I revisited the drawing that had confused me so much the last time I worked. Naturally, it made perfect sense almost immediately after having been away from it for awhile:

I think it was actually the text that caused my befuddlement:

But even the text isn't all that confusing, really. I must have just been fatigued; the cost of being a so-called knowledge worker is that there are days when the brain is every bit as fatigued as any other muscle can be after a long day of work. All it's saying is file those plastic bushings to a width of 3/16" on the F-1287C and 1/8" on the trim motor tray. Given the width of those parts are pretty close to 3/16" and 1/8" respectively already, the net result is that the bushings get filed away to the degree that they are just a little wider than flush with the surface of the parts. Easy, that. Makes you wonder what all the fuss was about.

I had also skipped over the stripping of the wires coming out of the trim motor and the crimping on of connectors because the crimper and strippers were out at the hangar. Having retrieved them, that step was soon accomplished. Interestingly, the plans call for one male and four female connectors on the trim motor wires and one female plus four male connectors on the wire that will run to the control panel. Further, the male connector on the trim motor is specifically assigned to one of the two all white wires.

Why? Why not five females on the trim motor and five females on the other wires? Hint: it has nothing to do with procreation.

I found the answer in the directions that come with the trim motor. They state that when 12 volts DC is applied to the white wires, the motor will run. If the polarity of the power applied to the wires is reversed, the motor will run in the opposite direction. Because you would never, ever want to have the trim control wired up backwards such that down becomes up and up becomes down, the connectors are installed such that the  white wires will always be connected in the same way. There was a jet (maybe a turboprop - I don't remember exactly) that crashed near here a year or two ago when on a maintenance test flight. The trim control had been reversed.

Neatness counts too, so an adel clamp is installed to keep the wires herded together:

You can see the nicely filed plastic bushings too.

The trim motor has to be attached to the trim tab, oddly enough, and that is done with a pivoting pushrod assembly. A threaded clevis and a stabilizing arm get bolted to a couple of aluminum frames:

The cotter pins that lock the castle nuts in place will get secured a little later. I just wanted to make sure that the parts weren't going to need to be disassembled again. Cotter pins are supposed to be a one-time use item.

The actual pushrod gets clecoed into place using two pre-drilled holes on each side and four more holes on each side are match drilled:

Drilling through the second side is a little tricky since the holes aren't offset from each other; the drill bit will hit the cleco on the other side if you aren't careful. The drilling leaves some messy holes, so the clecos are removed and the holes in the pushrod are deburred:

Once cleaned up, the rod gets riveted in using a new type of rivet, the AD4H. The directions state that you should put pressure on the clevis plates (the aluminum sides) as the rivets are being pulled. I wasn't sure what that was all about until I realized that just like the drill bit when drilling the second side of the pushrod would hit the cleco, the second rivet would hit the rivet across from it. I didn't figure that out until I got to the second rivet, though, so I concentrated extra hard on keeping pressure on the first rivet as I pulled it:

Looks great, doesn't it? I thought so too, but I just couldn't shake the nagging feeling that I had forgotten something.

What could it be? The rivet is nice and flush, and the shop head is nice and bulgy.

Hey, wait a second. Why can I see the shop head??

Oh. That would be because I forgot to put the pushrod back in!!

Brilliant! A purely decorative rivet!

Now, in case you were wondering what distinguishes an AD4H rivet from the normal LP4-3 rivets we've used thousands times before, I'm here to tell you. It is that they are inordinately hard to drill out! The 'AD' that I at first thought stood for Attention Disorder actually indicates Ain't Drillable. I tried and tried to drill down through the center of that rivet, but the mandrel is clearly made if Impervium. As in "completely impervious to drilling." I finally just ground the head off with the Scotchbrite wheel and pulled the rivet through the other way:

How fun!

Pressing on (so to speak), I quickly discovered why pressure is required when pulling the next rivets:

Once I had finished using 13 of the 15 provided rivets (and how I hope that I don't soon come across a step requiring three AD4H rivets!!) to rivet 12 holes, it all got bolted together, surprisingly easily. A threaded receptacle had to be inserted into the end of the pushrod and match drilled and riveted in. A bearing that will attach to the trim tab is then screwed in and secured with a jam nut. I couldn't get the threaded receptacle to go into the pushrod at first; the two starter holes drilled by Van's hadn't been deburred and the rough edges were blocking my progress. A 'T' size drill bit used as a reamer quickly resolved any confusion on the part of the pushrod - "you will accept this little gizmo, or else!"

At this point, there really is nothing much left to do until the fuselage kit arrives. And you know, I might just be okay with that.

Tuesday, January 19, 2010

While we're waiting

I'm having withdrawal pains as I impatiently await the arrival of the fuselage kit. I've read through as many revision pages concerning the fuselage as I can find on Van's web site, but there just aren't that many.

I did find it amusing to find a page that boldly called out the need for a 120 degree counter sink bit when using a flush blind rivet, the omission of which frustrated me so greatly when it was not called out during the building up of the horizontal stab's spar box. In cases like this, it is important to remember that the tail kit was one of the last to be released by Van's, at least with regards to the airframe kits. With that in mind, it becomes more understandable why Van's didn't see the need to tell us; the early builders had already learned when to use the 120 degree bit in earlier kits. These days, though, when new builders are selecting the tail kit as the traditional starting point, it would seem to be a good idea for Van's to circle back and take a fresh look at the plans for the empennage.

There were still a few parts sitting on the parts shelf, so I thought I'd go ahead and build the tray that will hold the electric trim motor. There are a few pieces that go through the remove plastic covering/separate/deburr ritual. There are also a couple of lengths of aluminum tube to be cut to a very specific length, presumably to be used as spacers somewhere. This was another step where the band saw was far superior to the hack saw. I did find it odd to see one of the lengths listed as 28/32" rather than 7/8", but it could be the case that presenting the measurement in 32nds rather than 8ths is Van's code for "don't be sloppy with the measurement."

The assembly of the tray is pretty straight forward, but I did notice that for the first time the plans dictate a preference for which way a blind rivet gets installed. They state that the manufactured head should be on the inside of the tray (or MFR. HEAD THIS SIDE, to use their lingo) most likely for reasons of clearance that will become apparent later. In any event, it makes for a tight fit with the rivet puller:

It can be done, though:

The brackets to hold the motor in place are clecoed in and match drilled through the four existing holes and two brand spanking new ones:

There are six truss head bolts and some itty-bitty little lock nuts that hold the brackets in place. The lock nuts are far smaller than any reasonably sized wrench or socket, so I was at a bit of a loss as to how to hold them while screwing the bolts through. Being lock nuts, it was a very tight fit. I finally just put them in my drill vise to hold them:

I imagine that's a rather unconventional method, but it worked just fine.

There's an arm that will attach somewhere downstream of the trim motor. It has to have a bushing pushed through it, and I did that using the same vise/socket methodology I used back when I was doing the aft bulkhead on page 10-04. The same method was used to push bushings into the pivot points on the tray:

At that point I ran into a pretty confusing drawing having to do with filing down the plastic bushings to a minimum or maximum size. Oddly enough, the confusion over the drawing was enough to temporarily ease my withdrawal pains quite adequately, thank you very much, although I'm not sure the ensuing headache was a good trade. It was a good time to stop anyway since the next few steps call for the use of the wire stripper and the wire crimper that I keep out in the hangar.

Sunday, January 17, 2010

On being "Done"

For all intents and purposes, I am done with the tail cone.

What I have found as I reach the latter stages of mid-life, though, it that one often has to qualify just what is meant by the word "done."

In the pragmatic sense of the word, while there is work yet to be accomplished on the overall empennage kit, in the absence of a fuselage to attach it to there isn't much point in doing it. For example, the next section in the manual details the process of attaching the vertical and horizontal stabs, and in turn attaching the rudder to the vertical stab. I may or may not do that now, mostly depending on whether the empennage will be easier to store with or without those surfaces attached. But the attachment of those surfaces doesn't require any sort of construction; those parts are already built.

This is an example of the fluid sense of the word "done." There are RVs out and about that even after more than 2,000 hours of building and an additional 2,000 hours of flying cannot truly be called done. In extreme cases, they aren't done because they haven't been painted. In more subtle cases, I offer up my own RV-6 as an example. A couple of months ago, I met the guy that built that airplane. He looked at the fiberglass fairings that streamline the juncture between the landing gear legs and the side of the fuselage and said something about them still not being done. The fairings that he had originally put on it had been, in his mind, only intended to be temporary until he could get around to making nicer ones. I too had considered them in exactly the same way, and I too never got around to replacing them.

It is for this reason that I have always been irked at the accusation that I never finish any of the things that I start. There are many things that I have finished, although some of them have taken much longer than is the norm. In the strictest sense, my college degree took from the Fall of 1979 to June, 1996 to get done. That's quite a lengthy period to attain a four year degree, but perhaps it's more understandable once you realize that there are eleven years of military service and the start of a career mixed in there as well. My private pilot's license took nine years to achieve, but those were nine years of traveling the world while in the military and earning a salary only slight better than minimum wage. Both of those made any length of contiguous flight training very difficult to do indeed. And that instrument rating I earned? How many people have one of those?

There are certainly counter-examples. There is an unfinished canoe in my basement, providing companionship to an uncompleted porch swing that will never see the porch and is very unlikely to ever swing. Those were projects that I attempted to do on a low-risk budget (mostly by buying wood that isn't suitable to the task of supporting bodies on the water or hung from the porch ceiling) because I was not confident in my abilities to build from scratch. Those were valuable efforts, though, in that I learned that I do not do well when trying to fabricate every part of a kit using my extremely limited skills. Counter to those two examples, there is a very nice kit-build kayak residing down there as well. The kayak isn't a perfect example; it has not yet been varnished. In that sense, it is no more "done" than an unpainted airplane. It floats, it's well constructed, and it even looks very nice. But it is not truly "done."

Whether it is fair or not, it is this history that will be used to judge your abilities to complete a project as complex and mind-bogglingly large as building an airplane. It is also this history that made this comic so outrageously funny to me:

(Don't sit there squinting; click on it to see a larger version!)

By the time you reach the age where your 50th birthday no longer seems like it is safely in the distant, almost science fiction future, you get to know a few fundamental truths about yourself. One of those truths in my case is that I have an insatiable hunger for new experiences. That hunger often leads to interest in new hobbies. Combined with another strong trait that I have, which is the tendency to try on ideas in the same way a woman likes to try on shoes, it can (and does!) result in the collection of a lot of detritus. Abandoned projects start to litter the closets and basement. It's inevitable. And there's no small number of shoes sitting in the closet gathering dust, too. It happens. Fact of life. Once you understand it, though, you learn to be on the lookout for it.

Of course, some interests stick. Flying, photography, writing - all have stayed at the forefront for years and years. You can see two of these at work in this blog, and all three in the Papa Golf Chronicles blog.

Having varied interests and a fundamental desire to create things has had salutary results in at least one area: my career. As a software developer, I get to design and build things every day of the work week. As a one-man show, I even get to decide what to build and when to build it. There is tremendous satisfaction in that, but it is tempered by the fact that the end result of my work benefits others far more that it benefits me. Well, indirectly, anyway. It certainly benefits me in a pecuniary sense. But it doesn't offer the pride of creation and the lingering sense of enjoyment that something like building the kayak did.

From the combination of all of those things things arose the desire to build an airplane. From an honest (or so I'd like to believe) assessment of my abilities and my weaknesses, I selected the RV-12. The RV-12 is the Building An Airplane for Dummies book of Van's airplanes in many ways but, as with the series of books in the "Dummies" series, there is enough meat to satisfy all but the hungriest builder. While the normal Van's kits have a completion rate of somewhere around 50%, I predict that something like 95% of the RV-12 kits sold will be completed. The RV-12 is far more similar to the kayak kit than it is to the canoe or porch swing.

So, here we are. While I am still in the very early stages of building an airplane and it would be the height of foolishness to definitively state that I have this challenge beat, the completion (such as it is) of a major component is of great significance. There are remaining challenges, and some of them are major. Forming the longerons, building the fuel tank, fitting the canopy: these are all major battles remaining to be fought before the war is won. Any one of them could ultimately be my Waterloo; only time will tell. But for now, the future looks bright.

The last steps, for now

Saturday dawned with the type of weather that would have essentially ruined the day for me back when actual flying was the desire of the day. But here I am with an airplane to build, perfectly happy with a day that isn't so cold that my dog refuses to go out for his morning business.

It was with mixed emotions that I went over to the hangar for a day's work. I'm thrilled that the tail cone is very nearly done because it indicates a milestone in the building of the airplane, but I'm also sorry to see the work end, even if it is just for a few weeks while I await the arrival of the fuselage kit. The fact is that I truly enjoy the work. So much so, in fact, that I feel the need to find a word for it other than "work." There are too many negative connotations to "work" for it to adequately describe what I'm doing as I assemble my new airplane.

I briefly discussed the next step at the end of the last installment of this series when I went on a frantic search for the F-1210B plate which was to be guided through the slot in the F-1278 Top Skin. Having eventually determined that the part in question was already attached to the existing airframe, I called it a day.

Today was a new day, and it was a simple matter to do just that. The top skin was easily put into position and clecoed in place:

With the top skin in place, we are to look for deformations in the skin caused by a bracket that rests just under the skin. These deformations would come from not getting enough bend in the bracket back when we fluted it to match the curvature of the frame; that happened so long ago (way back on page 10-02) that I had forgotten about it! If there is any deformation showing, the skin is removed and a file is used to shape the bracket into a more compliant form. I had no deformation showing, so I proceeded with the next step. That step is a simple two hole match drilling:

After that is a step that looks like it's going to be pretty complicated, but that complexity is a simple illusion coming from the fact that the plans tell you to do it twice:

I suppose it is a testament to the overall superior quality of the plans that little things like this are so notable, but it never fails to amuse me to see something like this still remaining on a page that has had at least one revision.

As I clecoed the very back end of the skin, I was somewhat concerned about the gaps that were appearing under the edges of the skin:

Clecos don't hold nearly as tightly as rivets do so I figured there was some chance that the gaps would disappear once riveted, but I wasn't sure I wanted to take that chance. Conversely, using the edge breaking tool to increase the "break" on those edges was rife with risk. As it was, those edges already had a sharper break than the rest of the edges. I was afraid that more break would be too much. In the end, I decided to go ahead and rivet:

It turned out fine. The rivets were enough to close the gaps.

All that was left was to install the half rib that will be the lower attach point for the fairing on the front of the vertical stab:

A couple of the rivet locations on that part were pretty hard to get at. I had to use the little angled wedge and a hand puller to get at them. One of the holes in the corner needed a little touch with the #30 bit, but I couldn't get it to reach. Somewhat ironically, I had to use the extended length #30 bit that I didn't need for the step that actually called for it.

The top skin is the only tail skin that doesn't have a J-stiffener already molded into it (although there are two that need extensions to the molded J-stiffeners) so one has be riveted on. The drawing on the plan is extremely detailed, but the text tells us that the notched end goes towards the rear:

It gets completely riveted in; it is an exception to the "don't rivet any of the holes in the forward seven inches" rule.

Everything else gets riveted. I found that I needed to turn the tail cone a couple of times to get good access, but fortunately it is still light enough to just lift if I need to:

The riveting went well enough, but it left a bad taste in my mouth. That's probably because at any given time I had a dozen or so rivets in my mouth:

I doubt if that's an OSHA approved method of holding rivets when you only have two hands, but... I only have two hands.

I haven't yet decided if I will go ahead and attach the stabs and rudder; it will be easier to store without those big parts attached. The only reason to do it now is that I have no more work to do and I might get bored. That said, the RV-6 still has some open jobs to be performed, so I will probably shift focus to that.

Here's the more-or-less completed cone:

Friday, January 15, 2010

The Final Stretch, or The End of the Beginning

There's not much left to do on the tail cone. There's still some riveting to be done, but about a third of that got knocked out a couple of afternoons ago when we had temperatures in the mid 30's. After the single digits and low teens of the last few weeks, it was nice to be able to work with the natural light from having the hangar door open and without the roar of the Cone of Comfort heater. All that's left to do is rivet on the top skin:

I found when I got to the step before clecoing on the top skin that there was still a small part back in the shop the needed to be prepped. It's nothing more that a small half rib that will be used to screw the bottom of the vertical stab fairing into. It has eight nutplates for the screws to go into. The nutplates and the rib itself need to be dimpled to allow the screws to go in flush with the outer skin. The dimpling of the rib flanges is quite easy and only took a few moments:

The nutplates themselves need to be dimpled too. If you remember back to the early days of the vertical stab, I had to do it then too. I was momentarily taken aback by this problem when I tried to dimple the first one:

See how the edge of the female dimple die will cause the nutplate to bend if I squeeze it this way? That had be befuddled for a minute or two until I remembered that there is a special carved down die for this kind of job.

Here's a side by side comparison:

You can see the difference when using the cut down die:

See? Nice and flat. The thing is, though, those dies aren't cheap. Cutting one down like that has got to be somewhat painful in a pecuniary sense. Given that the role of these nutplates is nothing more than providing a threaded receptacle for a few screws, I'm not convinced that I would even bother. I have the luxury of borrowed tools, so I never needed to make this decision. Just to see what it would look like, I went ahead and clecoed an undimpled nutplate next to one that had been dimpled:

The difference is discernible, but I don't know that I'd call it significant. What? You can't see the difference? Well, the nutplate on the left in the top image is the undimpled one. See what I mean? Discernible but not significant. Let your conscience be the judge as to whether the difference is worth the sacrifice of a dimple die or not.

Here's the half rib all ready to go out to the hangar:

Having had a riveting session interrupted by my failure to bring all of the parts that I needed out to the hangar, I read ahead to make sure that it wouldn't happen again. Lucky I did!

I was going to need an F-1210B to slide through the slot in the F-1278 Top Skin. And therein was a problem. I went over to the parts shelf to retrieve the part for deburring and preparation, but it wasn't there. In fact, there wasn't much of anything there. All I could find were a few parts that will eventually become the tray the holds the electric trim motor. I thought that maybe I had already grabbed the part off of the shelf to get it ready back when I was first preparing to install the tail skins, but it was nowhere to be seen on my work bench. A frantic search of the workbench and its environs produced no sign of the wayward part.

"Now where could I have put it?"

"Is it hiding in the toolbox? Nope. Behind the drill press? Nope. Oh for crying out loud, how could I have lost it??"

Five minutes of ever more frantic searching later:

"Oh, here it is!

"Already installed!!"

"Man, what an idiot I am!"

"I'm done with this for tonight. I think I could use a little helicopter flying."

And that's what I did.