Thursday, December 27, 2012

SB 12-11-09, Part 2

It took awhile, but eventually the impediments to continuing work on the service bulletin all melted away.

Christmas is over and done with, and departing with it are the stress and distractions incumbent in maintaining at least a patina of the societal demands of perpetual good cheer. I can easily and honestly maintain the Spirit of Christmas Past, it's the non-stop, full immersion Spirit of Christmas Present, which as we all know now runs from late September to sometime in early January, that taxes my patience. Fortunately my lad Cabot is easily pressed into service as my proxy.

I'm also completely over the shame and personal disappointment arising from my muddle-headed mis-drilling of a 3/8" hole as a 3/4" hole. Having now used the holes, I have to say it: had I not accidentally made these holes 3/4", I would have done it deliberately. Look how well they work! A 3/8" hole would have been far more difficult to use.

And as we can see in the upper right hand corner of this picture, perfectly sized caps were available to close the holes up when they're not in use. Oh, and the 6" long 1/4" bit was perfect for drilling through the center section. Any other bit would have been either painfully too short or too long.

It turned out that it was possible to use the countersink bit without removing it from its cage, but I wasn't really keen on having to hold it still while using it.

The replacement of the landing gear itself was a three hour ordeal performed with the able assistance of Pete and his son Warthog. It wasn't a great deal of fun. In fact, it was quite cold. I'd say the job took a good hour longer than it should have simply because our fingers were numb from the cold!

The brake lines still need to be reattached and bled, which is another job I'm not really looking forward to. But once that's done, I just have some paperwork to do in preparation for my inspection by the Feds.

Tuesday, December 18, 2012

"What's it like?"

You get a lot of questions from people that find out that you are building an airplane.

Some become routine.

Some test your ability to suppress an eye roll.

Examples of those are "When will it be done?" and "A real airplane? And you're going to actually fly in it??"

After awhile you build up a library of ready answers for the most common ones, along with the ability to spit out a wordy non-answer when the real answer would require too much time and effort. You know, much like a politician.

The hardest question of all, though, is, "What's it like? What is building an airplane like?"

It's hard to answer because there is no simple, concise response that can truly convey what the experience is like. Most people have never tackled a project that requires the level of commitment, persistence, tenacity, frustration, elation, perspiration, dedication, and time that comes with the job of building an airplane.  There are parallels that can help people to understand, of course, but few of those example projects eventually  result in a day when you are going to trust your very life to the end product.  It is that aspect, I believe, that erects an insurmountable communication barrier between those that have and those that haven't.  It is also why one of the more routine questions, albeit almost always a rhetorical one, is "Are you crazy??"

In some ways, the answer is "Yes, I  must be."

It is important to understand that building an airplane is not something you do. It becomes, to a very large degree, what you are. A project of this magnitude has an effect on your life. At work, at home, in the middle of the night when an anxiety attack resulting from an issue with the plane is keeping you awake - the project is always somewhere in your mind. A bad day at work will often result in a bad day working on the airplane. A bad day working on the airplane can easily cause a bad day at home. It becomes intertwined in personal relationships.

That goes both ways, though. The first time you step back from having placed the final rivet in something that actually looks like part of an airplane. The first time you move the control stick and parts of the airplane move in response. The first time you sit in it. The day you start the engine for the first time. The sense of accomplishment and the pride of having actually created a part of something that hundreds, thousands of previous generations could only dream about - people will be questioning what kind of wonderful drugs you're on. And with each of those moments comes the understanding, the visceral knowledge that someday, someday, it will fly! Which is, of course, tempered by the immutable fact that you will be in it.

That little demon is always in the back of your head, gnawing away at your elation.

That little demon has its purpose, though. There will be days of abject frustration. There will be parts of the project that are just plain hard. There will be temptation. "Screw it, this is good enough," the temptress will say. "Let's just get on to the next thing."  The little demon will have none of that. These are the times when that little bastard is going to insist that you take a step back, maybe even take some time off, and come back refreshed and ready to do that task right. He's there to remind you that someday you will be betting your life on the quality of this work. And if that doesn't do the trick, he is not above reminding you that the airplane has a second seat which will someday be occupied by an innocent whose life is riding on the same bet.

Is that an emotional burden that can be hard to carry? Hell yes it is! It is part of the reason that  building an airplane is not something you do, it is something you live. It is why even simple mistakes will plague your waking thoughts and disturb your sleep for days. And you will make mistakes. There are few things you can do in life that can be as humbling as a project like this. You will be furious with yourself. You will be astounded to learn how fallible you are. You will question whether you should even be doing this. "How could I have missed that?" will be a question you ask yourself every bit as often as a curious person will ask "When will it be done?"

You needn't be alone, though. At least in the case of my RV-12, there are other people that have gone before and are willing to share helpful tips and pieces of advice. Not all of it will be useful; you need to be the final judge as to whether you want to follow anyone else's lead. You will have visitors as you work. You may even be lucky enough to pick up ready and willing helpers along the way. Chances are that you will be blessed with new, lasting friendships.

Sure, there will be a few know-it-alls that think their way of doing any particular thing is the only way, but that's endemic to the breed of person that has the self-confidence to tackle a project of this magnitude. There are points of contention that actually bring out evangelistic fervor in some people. Emotions can run high.  It's not always easy to set that kind of thing aside and get back to focusing on your own work, but as with any of the plenitudinous other frustrations, it's best to just step back for a few days and get settled down before doing any work on the plane.

That is, in fact, one of the more important lessons to learn. There are days when you aren't working on the airplane because you want to, you're working on it out of some sense of obligation or pressure from external influences. It is at these times when you are more likely to make mistakes. Your mind isn't fully engaged. You can read directions that clearly state the need to drill a 3/8" hole and proceed to blithely drill a 3/4" hole. You will then spend a few days beating yourself up over it.

The lesson to be learned is to know when to not work on the plane.

An adjunct to that lesson is to know when not to put pressure on yourself. Unless there is a good reason to do so, deadlines for completion are best avoided.  Delays are inevitable. Parts may need to be replaced. Tools may need to be acquired. Midstream changes can come flying in from the factory at any time, often requiring the re-work of something you thought was finished and done. Knowing at an intellectual level that these things can and do happen helps, but it cannot prevent the immense frustration that comes from an unexpected delay. It's just one more thing to deal with.

So in light of all that emotion and complexity, what's my answer when someone asks me what it's like to build an airplane? How do I condense all of this down into an easy answer that at least partially conveys the depth and subtlety of it all?

Like this:

"It's a journey of self-discovery."

Monday, December 17, 2012

Extra Innings

This is my second try at this post, the first having been deleted because it was just a bit too frank. A bit raw, if you will.

I find myself in a strange and unfamiliar place all of a sudden. I'm sure this is something that will pass, and hopefully quickly. The thing is that I think I've hit a wall.  At this moment, I really just want this project to be done.

Maybe it's this service bulletin - it's a lot like getting to the bottom of the ninth and finding that the game is going into extra innings.  I'm just not in the mood for it and it is having a bad effect on my thinking. I just can't seem to get out of my own way. It feels like it has been one screw-up after another. It's like waking up to find you suddenly have two left hands, and you're right-handed.

It's odd to be hitting me this late in the game. I got past the longerons. The canopy is done.  In the grand scheme of the last three years, this work is relatively simple. I don't understand why it's suddenly all so frustrating. I don't understand where this mental haze has come from. Seriously, drilling 3/4" holes instead of 3/8"?? Who does that??? I ordered a countersink bit that's too small for the job. I ordered it in the first place so I wouldn't ruin one of the countersink bits that I've been using all along by having to chuck it into the drill press, completely forgetting that the cage itself is chucked into a drill all the damn time!! 

My brain has called it quits.

And to do it all so.... publicly!! As much as I enjoy the writing, this blog can at times cause quite a bit of additional stress. I decided from day one that I would share it all, warts included.  There are days, though....  I'm this close to just shutting it down.

Maybe it has nothing to do with the current work. In fact, I hope it doesn't. Maybe it's just carryover from the stress from the paying gig which is worthy of another blog in its own right. A lot going on there that has me well out of my comfort zone. At this point, should the Mayans prove to be correct, I'm not sure it wouldn't be an improvement.

I guess it doesn't matter where this is coming from - it's here, it's now, and it needs to be dealt with.  Writing about it here is a start - the act of putting things in words on a page has a way of getting the circling ideas out of my head. It's therapy, in a way.  Confession: it's good for the soul.

I'm going to just push this all aside and get through the last couple of days in the mines before my annual 13 day sabbatical.  Things will look better when I only have one thing to deal with. I'm sure of it.

Thank you for your patience.

Sunday, December 16, 2012

SB 12-11-09, Part 1

The parts required to complete the landing gear fix finally arrived, and with them came unseasonably warm December weather. It couldn't have worked out any better! With a comfortable 50+ degrees on tap for the weekend, Pete and I decided to get as much done as possible before the inevitable cold weather returns.

I started out by marking the locations where I would be drilling 3/8" holes in the belly of the plane. These holes will provide access to four of the bolts that hold the landing gears legs onto the airplane. This access will allow for periodic inspection and re-tightening of the bolts as required.

As usual, I very precisely located the spots for the holes, knowing full well that the actually drilling of the holes will result in very imprecisely located openings. It won't matter much; there will be plenty of wiggle room for the socket extension.

With a few years of bitter experience telling me that drilling with the step bit generates lots of shavings and that gravity will ensure that mot of them fall into my eyes, I made sure to wear my safety glasses. As is typical when I do this, they only managed to block approximately ninety percent of the falling detritus. The rest will float out in tears over the next few nights.

There were eight (four per side) difficult to get at rivets to be removed down inside the center section. The only way to get at them was to climb into the plane, something I really don't like doing when it's supported only by sawhorses.

A big part of the problem that caused the release of the factory service bulletin was wrinkled side skin as a result of loose gear legs wobbling around. Unsurprisingly, a big part of the fix for the problem is hefty skin doublers. All of those circles are new holes that need to be drilled into the side skins. These doublers will improve the strength of the side skins by at least an order of magnitude, causing me to wonder just how weak this part of the design was in the first place.

Having two drills handy made it easy to get both sides done concurrently.

Also tagged for increased robustitude were the steel "wear plates" that formed half of the metal sandwich that held the gear legs in place. Looking at the replacement parts as compared to the original parts again made me wonder just how weak the original design was. The new parts are in the back - just look at how much thicker they are than the original parts!

As I was drilling old blind rivets out of the side of the fuselage, I couldn't help wondering what we would do to get the old rivet shop heads out of the sealed area of the fuselage. Van's suggestion was to use a 3/4" diameter piece of rubber hose attached to a shop-vac to suck the little buttons out of the enclosed areas. That worked poorly. In fact, I don't think I was able to remove a single piece of rivet. It was impossible to see inside the area in order to find the little bits. Leaving the operation to random chance by waving the tube blindly around inside the airplane didn't seem like a very good idea.

Pete came up with a better idea. He covered a finger in masking tape with the sticky side facing out and just poked around in there getting rivet bits to stick to the tape. He later improved on that plan by shaking the airplane around a little bit to encourage the rivet droppings to roll to the lower bulkhead where he could collect them in bunches.

Meanwhile, I riveted in some new, thicker side stiffeners. Access to the rivets was somewhat inconvenient.

This rivet location was particularly bothersome. The only way to reach that rivet with the puller was to follow Van's directive to tap the big brass spar bushing to push it back out of the hole in the spar. It's in there quite tightly, so I am not convinced that "tap" is the appropriate word. It took pounding to get it to move. I wasn't keen on the idea of pounding soft brass with a steel sledge hammer, though.

What we ended up doing for both moving the bushing out and pushing it back in was to use a small chunk of 2x4 to provide a soft(er) surface against the face of the bushing and a length of wood to use to pound on with the sledge. This work very, very well.  Below is a picture of the setup for pushing the bushing back in.

Even with the bushing out of the way, the rivet puller was at a slight angle when trying to pull the rivet. These are not the normal blind rivets used in the rest of the plane - these are special rivets known as "cherry rivets." They are much stronger than the regular rivets used just about everywhere else on the RV-12, and something about that makes them impossible to pull at an angle without the mandrel immediately breaking off. When this happened, it left the remainder of the rivet in the hole with no way to complete the pulling. I was at a loss as to what to do about this, but after thinking it over, I decided to treat is as if it was a solid rivet. In other words, I just drove it in with a rivet gun and a bucking bar. The little brass thingy is a little extension we made out of brass plumbing parts from the hardware store. The cherry rivet actually isn't a solid rivet, so I used very light sir pressure and only a few taps from the rivet gun to finish its set.  Looking at the shop head once I had finished tapping it, it was impossible to tell that it had been done any differently than they ones I set with the rivet puller.

NOTE: There are those that believe that it makes a difference from which direction the shop head of the rivet is formed, so use your own discretion.  I can't see what possible difference it could make and I am perfectly comfortable with my decision, especially when considering the relative weakness of Van's original design that used a normal LP4-3 rivet in this exact same hole, but seriously, do what you think is right. I'm just here to share my experiences, not to tell you how to build your airplane. It is becoming abundantly clear to me why Dan Checkoway deleted his entire RV-7 build blog, though.

Once that was done, it was a simple matter to rivet in the side doublers.  Well, it would have been simple if the cherry rivets didn't display a propensity to jam up the Harbor Freight pneumatic puller. The first time it happened, I took the puller over to the work bench to disassemble it in order to figure out why it had jammed.  That in itself wouldn't have been a problem, but I have somehow developed the bad habit of absent-mindedly carrying stuff with me and leaving it sit somewhere else, only to return to the work site to find something mysteriously missing. In this case it was the small plastic bag of cherry rivets. Nowhere to be seen. And quite the mystery it was, too. I retraced my steps, but they were nowhere to be found.

Having a far superior institutional memory than I do, Pete remembered the lesson that we learned after finding a dropped part in the most unlikely location (it had fallen into the open bottom of one of the control sticks), that lesson being that odds are that if we can't find something easily, it has found its way into the very last place you would expect it.

And so it was. We found the bag of rivets.

As usual, the actual riveting was really a bit of an anti-climatic event once we figured out how to easily un-jam the rivet puller.

The next steps involve the preparation of the new mounting plates. Unfortunately, one of the plates requires countersinking with a countersink bit that I don't own. We were unable to find one at any of the local hardware stores, so I had to order one on the internet. Here it is, for anyone that may need one:

Edit: I was just planning to use one of the standard 100 deg 1/2" piloted bits in the spindle portion of a disassembled countersink cage.

The bit I ordered is too narrow. I'm going to try the suggestion above if the bits I happen to have on hand are wide enough.

There are also four 1/4" holes to be drilled all the way down through the center section and those big mounting plates. As long as I was ordering the countersink, I ordered a nice 1/4" bit.

We're on hold until those arrive.  Hopefully they will end up being the right tools for the job.

Sunday, December 2, 2012

"For awhile, they were asking how long it took to build."

"Now they're back to asking when it will be done."

One of the nice things about working in the hangar on a nice Saturday morning is the steady stream of visitors that are either stopping by for an update or those intrigued by the sight of an airplane being built. Both groups have been known to ask both of the questions above, but the latter group, the first-time visitors, had recently starting to ask only the latter question.

Not anymore.

The reason for that has to do with the number of things that have been undone as I prepare to receive the new landing gear reinforcement parts from Van's. As usual, that is a somewhat open-ended commitment from Van's - they do things at their own pace and aren't always particularly precise when it comes to telling us when to expect things. It's a lot like having the cable service department tell you on Monday morning that the repairman will be there sometime between 9:00 am and..... Thursday.

"They'll be there when they get there," if I may paraphrase.

No sense lying idle while waiting, though. The landing gear legs are off already, as you may recall, so this weekend I did the next couple of steps. Van's seems to have decided to address all issues with the landing gear installation big and small, and one of the smaller ones was a slight interference between the two big landing gear attachment brackets and the large end of a few rivets. Rather than have us remove the rivets (which wouldn't be easy or smart), Van's has us grind the edges off of the steel brackets.

That may be smart, but it's not necessarily easy. It involves the grinding wheel - one of my least favorite power tools. Parts being ground (grinded?) get very hot, there are a lot of sparks flying around, and I'm always a little nervous that something is going to break and get flung off of the wheel in the general direction of my head. And I don't need any more damage to my head, thank you very much!

As predicted, the bracket got pretty hot. I could feel it getting too hot to handle even with gloves on, so I had to set it down to let it cool off between grinding sessions. Luckily it was pretty chilly in the hangar and it cooled off relatively quickly. I filled the time by drilling out the rivets that will be replaced when the new doubler than Van's is sending to beef up that part of the side skin arrives. The gloves came in handy for that job too, but to protect them from the cold rather than the heat.

I made a special tool for drilling out the rivets based on a tool I had seen before. It was as simple as sacrificing a $5 Harbor "THE Place for Fine Sacrificial Tools and Furry Mammals"  Freight center punch by grinding down its point so that it would fit into the mandrel hole of an LP4-3 rivet.

Usually it only takes a punch or two to knock the remaining mandrel out.  Once that's done, slow drilling with a #30 bit will take the cap of the rivet off. Once that's done, another punch or two will knock the rest of the rivet out. In some cases a light spin of the drill is needed to add encouragement. Mostly, though, it's pretty easy.

Right up until it's not. In this case, the tab that the rivet went through just pushed away from the punch.

I tried grabbing the tab with a cleco clamp.

That still wasn't enough. I added the blade of a small screwdriver to the mix. That held the tab firmly enough to let the center punch do its thing.

There! One side done!

Between bouncing from grinding to rivet removing and back again, I mostly finished up the preparation for installation of the Service Bulletin parts.  The foresight and extra effort that went into getting ready for the parts before they get hear will surely be paid off with a nice, lengthy wait for the parts to get here. 

 Because that's the way these things go.

Monday, November 19, 2012

And now we wait...

I've been plodding along on my acceptance testing with no great sense of urgency because, well.... it's out of my hands. Yes, another open-ended, unforeseen delay. 'Tis the nature of the game. This time it has to do with the landing gear. One Service Bulletin has already been released by Van's that has grounded the fleet until such time as some inspections and adjustments are made to the way the landing gear legs are bolted to the center section of the fuselage. Those of us still building are furthermore even more firmly enmeshed in the problem in that there is a special directive aimed at us, the Reader's Digest version of which can be encompassed in a single word: "STOP!"

 The latest update from the factory is that they have developed a small parts kit comprised of some skin doublers that will have to be riveted to the sides of the airplane. Unfortunately, the couple of hundred rivet holes that the doublers will be riveted into already contain a couple of hundred rivets on my particular plane. Those will all have to be drilled out in order to install the new doublers. I haven't talked to the FAA guys about this - I suppose that it's possible that they would go ahead and do the airworthiness inspection even with outstanding Service Bulletins, but I kind of doubt it. In any event, I'm waiting. Which isn't to say that there is nothing to be done while I wait. It's more the case that what there is left to be done is not sufficient to fill the available time, so I've just been dabbling at it. Which means more time to play with Cabot!

And his friend Buster:

The acceptance inspection has things coming on and off of the airplane at a prodigious rate. The lower spark plugs needed to come out for one part of the inspection and I was a little concerned about the difference in the look of the plugs between the front cylinders and those in the back two cylinders.

This is apparently common to the Rotax, so it was an unwarranted period of angst. I'm having a lot of those, lately.

Van's wants us to test the sanctity of the pitot-static system which is, of course, a laudable directive. Thet said, their chosen methodology was not very confidence inspiring. Slipping a syringe over the pitot tube and holding it while testing the leakage rate was nearly impossible without tainting the results with uncontrollably small changes in the pressure from the thumb holding the plunger. 

It was accurate enough to detect a massive leak in the pitot system, though, which I (not very) quickly tracked back to a problem that I had encountered when putting the pitot fitting into the ADAHRS box.  See the threads showing on the fitting on the left? Yeah, that ain't quite right. The thing is, it was as tight as I could get it without risking breaking something. I ended up taking it back out and putting a very, very small dab of Boelube on the threads. That made it screw back in without the discordant resistance. It sounds easy now, but a lot of hours were spent on this operation. 

Testing the static system was better, but not by much. The way that is done is to tape over one of the ports, then use clay to form a seal around the syringe and the other static port. This too was a completely imprecise method and it took quite awhile to get comfortable with the results. Which isn't even to mention the concern over getting modeling clay into one of the static ports.  

Then it was time to remove the gascolator to check the internal filter for obstructions that may have flowed down from the fuel tank. The location and design of the gascolator makes this a burdensome job. Getting it off of the plane was bad enough, but replacing the safety wire when re-installing it was an exercise in frustration. The first effort was sub-par and despite the strong temptation to just leave it in place I ended up re-doing it. Knowing that I'm going to have to do this every year for the rest of my life, well, that's not the happiest thought right now. Especially when you consider that the filter screen was impeccably clean.

Having exhausted all of the little things, I moved onto the weighing. The first step is getting the airplane level before it even goes on the scales. The idea is to place a line on the hangar floor that gives a consistent measuring point from which to determine how far aft each axle is. You would think they would be identical, but one of mine ended up being a half inch further aft than the other. 


Van's has us put the main wheels on 2" thick blocks, then add or remove air from the nosewheel to get the plane level.

Two amazing things happened when it came time to plumb the spot on the floor. 1) I had a plumb bob. 2) I was able to find it.  Amazing!!

Once the requisite measurements are recorded, the plane goes up on the scales. I accomplished this via an inadvisable method: I got under the wing and lifted it with my back while Pete slid the scales and block under the wheels. It ended up requiring that nearly all of the air be let out of the mains (not the nose, as expected by Van's) to get the plane level. 

The final result was 701 pounds. Which considering that a more typical weight is 726 pounds sounded wrong to me. Very wrong.  

I stewed about it over night and decided that the only recourse would be a re-weighing. Having had a night for my back to register quite strident complaints about my lifting method, I decided to use a slower yet decidedly more back-friendly approach.

Thinking that maybe the extremes that we had to go through to level the plane with the 2" blocks had adversely affected the precision of the weighing, we didn't use them the second time. By releasing equal pressure from the left and right mains, we were able to get a nice level. The results were much more realistic at 719 pounds (the picture shows 718, but the two little side panels that close the fuselage sides at the top of the landing gear legs aren't installed and the number on the scale was bouncing between 718 and 719 indicating something between 718.9 and 719.0). The 719 value stands favorably against a 726 pound airplane that has the lighting and/or interior kit(s) installed.

There are a few more inspection things to be done, the paperwork needs to be gathered and sorted into a presentable package, and I have to find someone to engrave the data plate. After that, it's just a matter of waiting.