Sunday, March 20, 2011

A big flap

Well, actually, there are a couple of big flaps to talk about. Of course there is the big flap that I'm building to hang on the back side of my left wing, but there was also a different kind of flap in the RV-12 builder community last week.

The story as I understand it is that my building buddy Kyle, lead singer and tambourine tuner for The Jackson Two, was installing a welded part in his RV-12 when a very disconcerting issue arose. The part in question is part of a chain of parts that work together to provide a linkage between the control stick and the flaperons. That's pretty important stuff; the flaperons are what allow a pilot to turn the airplane, or to prevent the airplane from turning of its own volition. Both are equally important to everything in the pilot's life, with the possible exception of retirement planning.

Here's what the part looks like:

Those flat plates with the holes in them are welded to the supporting tube and powder coated by Van's. In theory, anyway. As Kyle was preparing to match drill one of the plates, it fell off in his hands.

Apparently that one had been tack welded to hold it in place for a weld that was never performed.

Kyle immediately went to the Van's Air Force internet forum (which is independently owned and operated; it is not affiliated with Van's aircraft) and posted the following series of messages:
This evening, we were getting ready to match drill the wd-1215 brackets with the wd-1214 flaperon torque tubes and the wd-1215 bracket flange came off in my hand. Looks like there was no welding other than a tac weld.
There were a number of "Thanks for pointing that out - I will check mine immediately" types of replies, but it didn't take long for the fissiparous nature of the builder community to show. Mixed in were a number of messages stating that the building is the final inspector and in essence saying "Sh!t happens, it's your job to deal with it." Which, as I stated later once I got involved in the thread, is good advice that quite widely misses the point.

But before it got that far, Kyle posted an update:
Just called VANS. They are sending me two new WD1215's L and R. They said they have recvd a couple other calls this morning in regards to these parts. The parts person i spoke with said i should have called them (VANS) first before posting here. I take issue with that.

One poster said he advised VANS in Feb 2010. That is a year ago and nothing was done.
[Emphasis mine, remainder of message redacted to remain within fair use copyright rules]

I have to confess that the "buck stops with you" attitude piqued my interest. I added:
I wonder if a jury would see it that way, particularly in the case of an E-LSA where Van's Aircraft is the manufacturer of record. The E-LSAs are too new for that to have been tested in a courtroom and we all hope that it never gets tested in that way, but it does seem that a preponderance of caution on the part of Van's would be a good approach.

I am also of the opinion that another of these defective parts showing up a year after the first known report with no record of a notice or bulletin being sent to assemblers does not inspire confidence.
I've talked about the E-LSA rules here before, and the difference between that set of rules and the normal experimental aircraft rules. In a nutshell, with the E-LSA we are required to build exactly to the plans, but a normal experimental can be modified from the design by the builder. In exchange for the loss of autonomy in the build process, the manufacturer (in this case, Van's) remains as the manufacturer of record, and ostensibly the liable source should anything go wrong. With the other set of rules, the builder becomes the manufacturer of record and also takes on the liability.

Not everyone understands that, though. To be fair, most people frequenting that forum have no interest in E-LSAs and have never had reason to familiarize themselves with the subtleties of the newer rules. That explains this reply:
Lawsuits should never even be whispered about; it’s only bad for your hobby. I don’t know anything about LSA but as far as EAB goes it falls to the manufacture/builder and you don’t want it any other way because there would be no kits available for us to build.
I agreed with this guy's sentiment, though:
The response of Van's parts employee, if reported in context accurately, was a discouraging note, I thought. Hopefully, that doesn't reflect the attitude of the Van's staff as a whole and the employee will be counseled that, when a safety of flight issue is involved, it's perhaps not the time to rely on a single, formal line of communication.
In fact, it is that statement from the unnamed employee that bothered me the most. It was enough to get me to wade in again, against my better judgement (which, to be fair, is pretty much par for my course):
In the case of welds (and worse, welds covered by thick powder coat), I sure hope Van's isn't counting on me to find poor workmanship. I'm am neither qualified nor equipped to judge the quality of a weld. To put it bluntly, that is what I am paying Van's to do. Not all poorly welded parts are going to conveniently and fortunately fall apart quite as easily as Kyle's did.

I also stridently disagree that discussion of potential lawsuits is somehow off limits. It is the world we live in and playing ostrich is not going to solve anything. I think it would be foolish to not consider where the liability lies with the airplanes we are building. One of the benefits of an E-LSA over E-AB is where the liability lies; you can't market the benefit when it's convenient and hide from it when it's not. We sign a contract saying that we upheld our end of the deal by building exactly to plans; the manufacturer has to hold up their end too by meeting their responsibility to make sure their product is safe.

Finally, I find any criticism of Kyle's decision to share his experience with us abhorrent and frankly I'm shocked by it. I now can't help but wonder what other problems have been hidden from us. I understand the motivation behind it - credibility and trust once lost are very difficult to recover - but this is serious business here. There is no room in this industry for the hiding of problems like this.
Van's released a service advisory regarding this issue very quickly, thus making the point about "calling them first" moot. For some reason, this was viewed as justification for arguing against any criticism of Van's, and somehow exculpated Van's of any responsibility for that part being shipped in the first place. One commenter went as far as saying that we all owed Van's an apology (which seems exactly backwards to me) and that "anyone that can't differentiate a tack welded part (powder coat or not) from a fully welded part should not be building an eab/lsa."

That was a bit much for me, so I posted this:
That's a fine point, as far as it goes. Given that it is the builder's life that's on the line, a high degree of last-chance quality control is certainly prudent. On the other hand, there are two parties in this transaction: one that may or may not have the requisite background and experience to know precisely how a weld is supposed to look, and one that has decades of experience in knowing precisely how a weld is supposed to look.

Only one of those parties is selling those parts for profit. That profit is earned by doing the work that the first party can't do for himself, and ensuring that the work they do is complete, accurate, and safe.

I'm the first to say that this could have happened to me just as easily as it happened to Kyle. I trusted (incorrectly, as it turns out) Van's to take care of the basics of quality control. They are a trusted manufacturer with years of experience; that factored heavily in my decision to purchase from them. I suspect a lot of us got a very low cost lesson through this incident; I know that I did. Education is half the of the "recreation and education" basis for building our own airplanes and I'm happy to have been taught a very valuable lesson about it, and I'm even happier that it came at no cost. There's no hiding the fact, though, that the cost could have been tremendously higher.

Oh, and those decades of experience that Van's has? It would have been measured in months if the qualifications for building one of their kits included the abilities required to have built the thing from plans. I'm sure there are purists that believe the RV-12 was a mistake for Van's because it is targeted at inexperienced builders that don't have the chops to build a "real" airplane, but that changes nothing. The relative simplicity of the RV-12 attracts a builder that would never have attempted to build any of the other RVs - or at least one such builder, anyway.

I speak for myself alone when I say that I clearly do not have the experience or knowledge to gauge the workmanship of every single part of the kit and that I am (was) leaning on Van's to do that for me.

I make no apologies for that.
Between that and the work I have to do on getting the RV-6 through its annual inspection, there were a few days that I stayed away from working on the RV-12.

Which brings us back to Big Flap #1.

All of those parts that I fabricated before needed to be attached to the flaperon spar. That meant match drilling.

Those washers on the bolt running between the two parts are used simply to set the required spacing, near as I can guess. I would have preferred to have been given an explicit measurement, truth be told. Too much is at risk to trust that I found the correct washers mixed into the big bag o' washers.

These are unclad aluminum parts and need to be primed:

This part in particular was an interesting riveting job. Those holes near the vertical part require AN470 round head solid rivets, and getting that head up flush against the side of the vertical plate was going to be a problem. Fortunately, I learned a long time ago that Van's will tell you when the direction of the rivet matters; if they don't specify a direction, I just use whichever direction is easiest. In this case, I just inserted the rivet from the other side.

Moving on to the little ribs, I found that in some cases the rib wouldn't fit into the spar straight in because the flanges of the spar were bent inward. I just put the ribs in at an angle, then straightened them up.

The riveting of the ribs was the same as riveting the paddle: in some cases it was easier to bring the rivet through the rib and into the spar, in others it was easier to go through the spar into the rib. A few of the ribs used both options.

Then I had to peel blue plastic off of the flaperon skins, one of my least favorite things to do.

I had just clecoed the skins to the flaperon skeleton prior to riveting them on when I heard on the control tower scanner that the guy with the Piper Aztec hangared next door was taxiing in. I had the hangar door open, and this guy insists on blasting my hangar with a nearly full throttle blast of air when making the turn in front of his hangar before parking. That would have blown my wings off of the rack and done all kinds of damage. In the years he's been doing this and despite my having pointed out to him the mess he makes in my hangar when he does it, he continues to do it with reckless abandon. I decided that it would be a good idea to get the door down and move my car. It was close enough to quitting time that I just decided to leave the riveting until later.

Sunday, March 13, 2011

Fabulous flaperon fabrication

This was the kind of weather that would have frustrated me to no end in the days before I had an airplane to build. Tauntingly blue skies were calling for me to either join them in the RV-6, or at least marvel at them during a long, destination-less drive in a convertible. Alas, winds that where blowing at 26 knots when they weren't really letting us have it, and at 34 knots when they really wanted to drive home the point, kept me on the ground, while temperatures just a few degrees below the level needed for even moderately comfortable top-down driving precluded an open-air ride.

But these days, weather like that is just fine. I was able to spend a comfortable five hours working at the hangar.

Having passed over the fabrication of some parts in favor of the more entertaining flap counterweight drilling, I had to back track to step one. As I was looking at the drawings of the part that I had to make first, it became much clearer to me why The Jackson Two had asked a local machinist to knock these parts out for them. As I mentioned before, there is something intimidating about all of those different measurements and radii and offsets and dimensions measured in 1/23" and, last but certainly not least, the critical nature of the part in question. You see, I just had to look ahead to see what this part is used for.

The explanation is somewhat lengthy, but the crux of it is that the flat "paddle" part will fit into a slotted part emerging from the side of the fuselage. That slotted part will rotate when the pilot enters roll commands via the control stick and/or moves the flap handle. The rotation of the slotted part will be transferred to the "paddle," which will in turn transfer motion to the flaperon. So, at the end of the day it is this part that I am fabricating that will determine whether or not I can turn the airplane, or even maintain level flight for that matter.

And yes, I will be making two of them, one for the left side, one for the right.

The parts will be cut from a length of angle aluminum. I did a series of useless measurements and markings before realizing that the only line I needed for the first step was the one that would cut the raw material to the total length of the part. As you can see in the drawing, that is 2 29/32". I can only measure to 1/16" on the ruler I have, so I convert the measurement to something like 30/32", and then simplify to 15/16". I measure the part to the 15/16" on the ruler, then mark the part at the little gap between 14/16" and 15/16".

I do that at two places on the part, then draw a connecting line between the marks to use as my cut line on the band saw.

To form the paddle, part of the other bend in the angle will get sawed away. There's going to be lateral tension against that upright part, so Van's wants a stress-relieving 1/4" radius at the junction. They have us do that by measuring to a certain spot and drill a 1/4" hole. When we cut the two lines to remove the unneeded metal, we will cut them so they intersect at the tangent of the hole, thus leaving a 1/4" radius on one quarter of the hole. Or something like that. The pictures should explain it better than I can.

I was trying to get the drill bit right flush up against the vertical part; you can see that I got it too close. Most of that part is going to get cut off anyway. I also cut off a thin strip on the horizontal part to narrow it down to the 1 5/8" width (surprisingly, it wasn't 1 19/32") called for in the drawing.

Another hole as to be placed and drilled. This one is 3/16". I used a center punch to mark the location, then used a small bit on the drill press to get the bit perfectly centered on the mark before clamping down the part for final drilling. I think even with those precautions, I got the hole just a smidgen off from where it's supposed to be. Time will tell.

There's a 3/8" radius around the center of that hole as shown on the planes. I used a little math to lay out the curve. Two times 3/8 is 3/4, so I measured 3/4" from the base to the top of the radius above the hole and marked the diagonal cut line from there back to the aft end of the part.

I used the band saw to cut the diagonal (as is evident from the not-so-very-straight line) and to round off the corners of the 3/4" radius. Then I buffed the whole thing up with the Scotchbrite wheel.

As I was working on the second part, Al the Tool Junky stopped by to see what was going on. He has a nice bench metal shear down in his hangar and offered to do the diagonal cut on the second part in the shear, the theory being that it would result in a cleaner, straighter line.

It did.

I was ready to quit for the day and was reading ahead to the next step when I realized that the holes that would have to be tapped didn't use the same size tap that I had bought for the wing tie downs. I said something to Al, and before you know it he not only had gone down to his hangar to get the tap but was fully engaged in the fabrication process. I had him cut the four 2" lengths of tie-down extruded aluminum on the band saw while I got the parts ready for the steps I will work on Monday night. There were eight more of those "narrowing" cuts to do (one on each side of the four 2" parts) and those too were beneficiaries of the metal shear.

We worked out a process of getting the parts properly aligned for drilling in the drill press, then Al demonstrated the proper way to tap a hole that deep. I had been using Boelube to help lubricate the tap, but he showed me something that works better: he dripped a few drops of MEK (paint thinner wold have worked too) down into the hole and used a little candle wax rubbed onto the tap. It went much more easily than the wing tie-downs had for me!

He took off after the first was done and I finished the remaining three. The first step is to align the part. We did that by putting a size N bit in the drill press and lowering it into the part. That forced the part into a good vertical alignment before tightening the hold of the vise.

The next step was to replace the size N bit with a size Q bit. This is the bit called for in the plans for drilling the hole. A little MEK was used here too for lubrication. The drilling was very easy. The hole had to be drilled to at least a one inch depth; I put a black Sharpie mark at the one inch depth of the drill bit. The MEK washed most of it off, but it was enough to make sure that I get the hole deep enough.

I like the way the shavings spiral up the bit.

With the hole drilled, the tapping is simple.

Here's the day's worth of fabrication. The four parts that needed to be tapped will get those tie rods screwed into them after they are mounted to the flaperon spars, two to a spar. The bearing in each of the tie rods will have a bolt put through it after being centered in the bearing brackets hanging off of the back of each wing. So, these fabricated parts are what will hold the flaperons onto the wing and allow them to pivot in the bearings in response to the command inputs transferred from the pilot through the paddle pieces (called "actuators")!

Pretty heady stuff, isn't it!! These are some critically important parts.

Wednesday, March 9, 2011

Help, just when I needed it most

Co-pilot Egg and Mr. Case helped me finish up the wing rack a couple of days ago so the work benches are now clear for starting the flaperons. Which, as it turns out, has only exacerbated other space issues.

Yeah, just try to fly that thing now!

I had new help for the flaperons. My new helper (who I will call 'Harley' because everyone here gets a nickname) is keen on airplanes and is fascinated by the construction process. Unfortunately, I invited him to come over on a horrible night. And I don't say that because it was pouring down rain. I say that because the first steps of the flaperon section are horribly boring, at least for anyone expecting to assemble stuff. Nope, the first step is one of those head-scratching fabrication jobs that involves a lot of measuring, cutting, swearing, and drilling.

I don't mind these jobs, actually. They're a fun challenge, but there is one little thing that confuses me. I simply cannot figure out why Van's insists on every measurement being an odd nominator on top of a '32' denominator. The measurements are all 17/32" or 21/32" and the like. This might just be me, but I can't measure and cut to 1/32" inch. I suspect that the saw blade is wider than that! Since the 1/32" is a throw-away anyway, why couldn't they go for 16/32" or 18/32", either of which are easily reduced to more workable numbers? I'd rather reduce 16/32" to 1/2" or 18/32" to 9/16" to be perfectly honest. I'd sleep better if nothing else.

So, rather than embarrass myself with blank stares and head scratching in front of Harley, I punted. Next page!

The big tube is stainless steel and is intended to act as a counter weight on the flaperons. It has something to do with control flutter, I think. It doesn't matter, really. "Mine is not to question why..." I'll not continue that quote; it's a little too close to the mark.

Here's the thing about the tube: it's stainless steel, and it needs to be match drilled. And that, my friends, is no mean feat. Match drilling into aluminum is not my favorite thing; match drilling into a nearly impermeable material was bound to be a real treat! The first step was to get the tube positioned.

Then the first hole! I started with a very small bit (#46 since I've already broken every bit between #41 and #46) to get a good indentation to hold the #30 bit, then went at it with everything I've got, that being the air drill, some Boelube, and a great deal of pressure. This is where having Harley there to hold everything still while I shoved on it with a power tool was a tremendous help. Honestly, I don't think I could have done it without him.

Here's something I almost missed. If I hadn't read ahead and seen a directive to remove the #40 clecos before match drilling into the little ribs, I wouldn't have noticed that I needed to have them in there in the first place.

After drilling all of those holes into the tube (I think there were eight or ten, at least), drilling into those aluminum ribs was sure easy!

Sunday, March 6, 2011

Getting physical

There are times when this airplane building business gets to be pretty hard work, at least as measured by a guy who wouldn't take an Urban Active membership if you paid him to. Now, when and if they start a chain of relaxation centers called Suburban Inactive, give me a call.

This weekend has been one of the more physically demanding ones. Yesterday I carried all of the contents of the finishing kit down to the Schmetterling subterranean parts warehouse, a big enough job in its own right, but followed that job with the task of breaking down the wooden shipping crate and lugging all of the scrap wood down there too. Very tiring for an old sedentary desk jockey like me.

There is a lot of really fun looking stuff in this kit. I can tell that there is going to be a significant change in the nature of the work from here on out. Unpacking the kit was fun in a way as I enjoyed playing the "what in the heck is this??" game.

This morning I did the inventory and got everything sorted onto the storage shelves.

With that done, I loaded up the flaperon parts, all of the tools that I had brought home from the hangar, and the fabricated wood pieces for the wing rack and hauled the load out to the hangar. The flaperon parts went on the shelf and I spent the rest of the afternoon assembling the wing rack, which is really just another way of saying "reminding myself why I'm not building a deck on my house instead of building an airplane." Suffice it to say that carpentry is not a calling for me. I knew it was going to be a long afternoon when Step #2 of the assembly was to undo Step #1 of the assembly.

The resulting wing rack will serve as an adequate rack for the wing, but it ain't much to look at. After a few tries, I was finally able to get a picture of it that looks pretty good.

Saturday, March 5, 2011

Shifting gears

You know you're nearly done with airframe construction when:

So it's time to start shifting gears from building an airplane-like sculpture to building an actual airplane. There are two extremes to gear shifts: the silky smooth, less than a thousandth of a second shifts of a modern Formula 1 car, and the coffee-grinder abuse of a school bus gearbox perpetrated by a seventy-five year old spinster taking her lifetime's worth of frustrations out on an innocent collection of gears. If I had to select one of these as a metaphor for my transition from wing kit to finishing kit, well... call me Granny.

It's a problem of real estate, you see. Only partially in the "location, location, location" sense, though. That particular aspect arose when I went to the hangar this morning to retrieve the spars for the flaperons that I had hoped to assemble in the subterranean Schmetterling construction bunker. Nothing doing; they're way too long to fit into my tiny Subaru. I sure wish I had determined that before packing up and lugging home all of the tools!

But no, my primary real estate problem is that I haven't enough of it. I've mentioned before that it's getting uncomfortably intimate in the hangar and it is now time to do something about it. The first step is to use this rainy, blustery Saturday to build a wing rack, hopefully with help from Co-builder Egg. With the wings stored on something movable, I will be able to adjust my limited worked area as needed until such time as I can free up the space inhabited by the RV-6.

Oh, about that:

RV-6 • $56,500 • FOR SALE • Beautiful and eye-catching low time RV-6 must go to make room for RV-12. 400 TT. Lyc. O-320 A2D 150 hp 400 TTS Factory Reman., Sensenich FP prop 400 since new. Garmin 396 GPS, Dynon D-6, ICOM A200, Intercom, KLN-89B GPS, strobes, nav lights, sump pre-heat, electric flaps. Nice interior. Always hangared. Annuals performed by a trusted A&P. This is a simple, reliable, low-maintenance RV-6 built in the spirit Van intended. Emails preferred. • Contact Dave Gamble, Owner - located Grove City, OH USA • Telephone: 614 277-1269 • Posted March 4, 2011 • Show all Ads posted by this Advertiser •Recommend This Ad to a Friend • Email Advertiser • Save to Watchlist • Report This Ad • View Larger Pictures •Finance

I'm very torn on this. The sooner it sells, the sooner I can spread out my work. The down side of it selling quickly is so obvious that it doesn't bear mentioning.

Something is going to have to happen soon, though. The finishing kit is here, sitting in my garage. This too presents something of a real estate quandary. I'd like to haul all of that stuff down to the bunker, but 1) the rain is relentless, and 2) I'm going to build a wing rack down there. Hmmm. Or not. I think I'll just cut and prep the wood down there, but nail it all together at the hangar. Otherwise I run the very real risk of not being able to move the finished rack to the hangar.

Tiny Subaru, remember?

"Do Not Roll!" That will be good advice when the plane is done, too. The RV-12 cannot be flown quite as robustly as the RV-6 has been.

The pre-built fuel tank is a thing of beauty. Mine would not have looked nearly as good, and would probably have added injury to insult by leaking.

It fits right in!