Well, it's started. My back yard was covered with frost this morning, thus marking the official beginning of cold-weather shop work. As you may remember, I built the tail cone in the dead of winter so it's not as if I've never had to work under those conditions before, but one kind of deacclimatizes over the intervening months. Granted, the tail cone was assembled in temperatures measured in single digits and it was a comparatively balmy 34 degrees this morning, but it was still a bit of a shock to find my cold, stiff fingers fumbling around trying to get a grip on a rivet.
First things first, though. There were a couple of things to take care of before diving into the job of riveting on the band that surrounds the top of the firewall. First, I had to address an issue that I discovered while researching the issue left over from last time. That was, of course, the problem of the ends of the band not sitting flush against the firewall. I was looking at other build blogs to see if there was some other part that gets installed later that will press those ends down (there's not - it would have to be fixed now) when I came across a warning from one of the first group of RV-12 builders. It seems that there is a nutplate hole in each of the side skins that will align with some nutplates installed in the firewall. These holes in the skins need to be dimpled for the flush screw that will be screwed through them, but the plans never mentioned it. The guy whose blog alerted me to the issue ended up trying to dimple the hole with the nutplate already installed. Easier, I thought, for me to just go ahead and do it now.
There were actually two riveting jobs that I wanted to get done. The first was the riveting of the twenty-five nutplates that had been clecoed in around the edge of the band. Before doing that I removed the clecos from a few of the holes near the ends and bent the bands so that they would fit flush against the firewall. It was just luck that I didn't have to remove the whole thing. As I was doing that. I noticed that a lot of the nut plates and firewall flanges weren't sitting flush against the inside edge of the band.
The first few were okay and I was able to go ahead and squeeze in the rivets.
As I got to the area where the nutplates weren't sitting well, I had to enlist the aid of a third hand to hole the nutplates tight against the band as I squeezed the rivets.
Vice Grips(tm) to the rescue. Again! They're the Coast Guard of tools, I'm telling you.
The second set of rivets would hold the hinge strip in place around the other side of the band. The hinge would have to be match drilled to match the pre-drilled holes in the band. To do that, I needed to clamp it into place.
I was just finishing that up when I had a visitor. He stopped by to see how things were going with the build. One topic led to another and we eventually got around to the subject of tools. Al refers to himself as a tool junky, which may well be true, but he seems more like a pusher to me. He's constantly offering to loan me tools that I know I will quickly become addicted to and want to own for myself. Seriously, if I were to spend just one day using a pneumatic rivet squeezer I know that I'd simply have to have one of my own. I mentioned that I was quite happy with the stuff I have, and in particular I was thrilled with my band saw. Except for one little thing, I said. And that is that I often find that I have to correct for twisting of the blade as I'm making cuts. Which, you know, makes a horrid screech and makes the metal that I'm cutting quite hot.
Well, yeah, it will do that when you fail to correctly configure it. Just a few twists of a knob or two cleverly hidden at the back of the saw and there was a part of the saw that I'd never seen before dropping down out of the housing. And even if I had known about it, it wouldn't have mattered much because it was horribly out of calibration. So, off he went on a mission to fix it.
At one point I sheepishly mentioned that the instructions for the adjustments that he was making were probably right there in the owners manual that came with the saw.
"Yep. What's that thing they say in your line of work about reading the manual?" he asked.
"Oh, you mean RTFM." [language warning!]
"Yeah, that's it. Doing that might have helped."
Cornered, I was. Caught right out. Plainly in the wrong, and abjectly defenseless. Nothing to do but squirm. But then it came to me: you fight an acronym with an acronym. Kind of like fighting fire with fire, right?
"I'm more of a WTOS kind of guy," I told him.
"Hmmm. What's that mean?"
There was no way he could have known, of course, because I had just then made it up.
"Oh, that means Where's The On Switch."
Zing!
After that, match drilling and riveting the hinge strips was a bit of an anti-climax.
Saturday, October 30, 2010
Wednesday, October 27, 2010
Back(s) in the saddle again
Does it seem like it has been awhile since I've worked on the plane? It sure does to me! The last couple of weeks have been laden with distractions. A couple of afternoon/evenings were devoted to trying to get the Dynon D-180 in Capt. Lonnie's RV-12 to "talk to" the autopilot and GPS. To the best of my knowledge, that still isn't working. There was a late business dinner and a couple of unscheduled late nights at work provided courtesy of the folks that sign my paycheck, and we all know how hard it is to say no to those kind of folks. We've had bad weather that has kept me away from the hangar, and we've had slightly less bad weather that was good enough to do a little flying. We had a flat tire on Co-pilot Egg's car that needed to be replaced, despite her belief that it wasn't all that bad - it was only flat on the bottom, after all, and why the big fuss?
Things might be getting back to normal, at least if today is any indication. I was able to get home from work, get my clothes changed, and get out to the hangar while there was still good light. There were a few loose ends to wrap up on the seat backs and I hoped to get them out of the way so I could move on to the upper firewall. While it has been difficult to spend any meaningful amount of time out there, I have managed to stop by for brief periods in order to get the seats painted. All that remained to do today was to mount the aluminum Toblerone braces to the backs of the seat backs and install the assemblies into the fuselage.
Speaking of the Toblerone braces (I call them that for reasons that will be obvious if you consider the following photos), I can't figure out exactly what they're intended to be.
They mount onto the seat backs with hinge wire, so they're clearly expected to be able to move. As near as I can figure, they act as a type of seat recliner, albeit offering only two slightly different positions.
In any event, the seat backs are complete and installed. Don't they look comfortable?
Yeah. No they don't. Well, the seat cushions come with the finish kit. They'll look a lot better with the cushions on them.
Time just flies by (so to speak) when I'm out at the hangar. It's one of the few places where I can work at my own pace and without interruption, so I tend to just putter around and relax. There are distractions, of course, such as today when someone I've never seen before showed up and pulled Doc's Varga Kachina out of the hangar and prepared to fly it. That wasn't really a distraction in and of itself - the real distraction was that it was quite windy out there and he was just letting the wind bang the flight controls around in a most disheartening way. It's hard on them to be banged around like that, and I really, really like that Kachina. It's none of my business, and I treated it as such, but it's somewhat akin to averting your attention when you see someone abusing a helpless child. Can't we all please just think of the Kachinas??
Moving on, I started on the upper firewall. It's a nutplate kind of part, at least at first. Well, actually, the first step was to cut some hinge for the cowl mounts. I needed a 26" length and a 12.5" length. Two of each, actually, since one half of each will go one the firewall and the other half on the cowl. I had enough hinge material for both of the 26" parts, but only enough for one of the 12.5" parts. Paying for sins of the past, that; the remainder was used when I messed up the hinge piece that got mounted to the lower firewall. Fortunately I have about 5' of the stuff in the basement, left over from when I ordered way to much for fixing the RV-6 cowl in an ultimately successful attempt to see if I could push the shipping charge up to 500% of the cost of the material being sent.
So, back to the firewall. Twenty-seven nutplates. Only a handful less than the number of trombones that led the big parade. And, of course, the dimpling and countersinking that attend such tasks. Two of the nutplates were simple dimple jobs, the remainder were countersinking. The part that gets all of these nutplates is a band to surrounds the upper perimeter of the upper firewall. It provides a home for the top cowl hinges in addition to the nutplate kibbutz with its twenty-seven residents. All in all, a completely unsexy part that contributes more than its bland look suggests.
Bit of a problem here. The band starts out flat which pretty much ensures that it isn't going to want to sit flat after being forced into a curve, but the dimpling of the outermost screw holes created a bend in the opposite direction. Now it really doesn't want to sit flat. I'm probably going to have to take the twenty-five clecos back out and pre-bend the band to get me out of this bind that allows for an incorrect bond.
Hey, have you ever noticed that 'bund' isn't a word? Too bad - I would have liked to use all five.
UPDATE:
From the mailbag: (Ssshhhh - he doesn't know I call him that)
Did you find any discrepancies on the 26" piece vs the photo in the plans??
Yep! The drawing for the 26" piece of hinge shows a hoop flush with both ends. That's neither mathematically nor physically possible and, in my deeply considered opinion, is yet another example of frivolous artistic license from those crazy rapscallians at Van's along the lines of "metric crescent wrench." Or just a mistake. Either way, I don't think it will make much difference since the matching piece will have the same number of interlocking hoops and the total length of the hinges will still be just as tightly coupled.
Things might be getting back to normal, at least if today is any indication. I was able to get home from work, get my clothes changed, and get out to the hangar while there was still good light. There were a few loose ends to wrap up on the seat backs and I hoped to get them out of the way so I could move on to the upper firewall. While it has been difficult to spend any meaningful amount of time out there, I have managed to stop by for brief periods in order to get the seats painted. All that remained to do today was to mount the aluminum Toblerone braces to the backs of the seat backs and install the assemblies into the fuselage.
Speaking of the Toblerone braces (I call them that for reasons that will be obvious if you consider the following photos), I can't figure out exactly what they're intended to be.
They mount onto the seat backs with hinge wire, so they're clearly expected to be able to move. As near as I can figure, they act as a type of seat recliner, albeit offering only two slightly different positions.
In any event, the seat backs are complete and installed. Don't they look comfortable?
Yeah. No they don't. Well, the seat cushions come with the finish kit. They'll look a lot better with the cushions on them.
Time just flies by (so to speak) when I'm out at the hangar. It's one of the few places where I can work at my own pace and without interruption, so I tend to just putter around and relax. There are distractions, of course, such as today when someone I've never seen before showed up and pulled Doc's Varga Kachina out of the hangar and prepared to fly it. That wasn't really a distraction in and of itself - the real distraction was that it was quite windy out there and he was just letting the wind bang the flight controls around in a most disheartening way. It's hard on them to be banged around like that, and I really, really like that Kachina. It's none of my business, and I treated it as such, but it's somewhat akin to averting your attention when you see someone abusing a helpless child. Can't we all please just think of the Kachinas??
Moving on, I started on the upper firewall. It's a nutplate kind of part, at least at first. Well, actually, the first step was to cut some hinge for the cowl mounts. I needed a 26" length and a 12.5" length. Two of each, actually, since one half of each will go one the firewall and the other half on the cowl. I had enough hinge material for both of the 26" parts, but only enough for one of the 12.5" parts. Paying for sins of the past, that; the remainder was used when I messed up the hinge piece that got mounted to the lower firewall. Fortunately I have about 5' of the stuff in the basement, left over from when I ordered way to much for fixing the RV-6 cowl in an ultimately successful attempt to see if I could push the shipping charge up to 500% of the cost of the material being sent.
So, back to the firewall. Twenty-seven nutplates. Only a handful less than the number of trombones that led the big parade. And, of course, the dimpling and countersinking that attend such tasks. Two of the nutplates were simple dimple jobs, the remainder were countersinking. The part that gets all of these nutplates is a band to surrounds the upper perimeter of the upper firewall. It provides a home for the top cowl hinges in addition to the nutplate kibbutz with its twenty-seven residents. All in all, a completely unsexy part that contributes more than its bland look suggests.
Bit of a problem here. The band starts out flat which pretty much ensures that it isn't going to want to sit flat after being forced into a curve, but the dimpling of the outermost screw holes created a bend in the opposite direction. Now it really doesn't want to sit flat. I'm probably going to have to take the twenty-five clecos back out and pre-bend the band to get me out of this bind that allows for an incorrect bond.
Hey, have you ever noticed that 'bund' isn't a word? Too bad - I would have liked to use all five.
UPDATE:
From the mailbag: (Ssshhhh - he doesn't know I call him that)
Did you find any discrepancies on the 26" piece vs the photo in the plans??
Yep! The drawing for the 26" piece of hinge shows a hoop flush with both ends. That's neither mathematically nor physically possible and, in my deeply considered opinion, is yet another example of frivolous artistic license from those crazy rapscallians at Van's along the lines of "metric crescent wrench." Or just a mistake. Either way, I don't think it will make much difference since the matching piece will have the same number of interlocking hoops and the total length of the hinges will still be just as tightly coupled.
Monday, October 18, 2010
Seat backs
You'd think the seat backs would be pretty simple parts and hardly worthy of an entire section in the plans, but such is not the case. They don't seem like much; all they do is provide a surface to support your back when you're sitting in the plane. But wait! They have to be removable, adjustable, strong, and it would be nice if they'd pivot forward to give access to the baggage area behind them. So they need to be at least moderately complex, right?
Well, no. They're pretty easy. Or should be, anyway, but we all know how these things go.
It started out well. All I had to do was cut the corners off of some hefty piece of angle aluminum. This is the kind of job that always endears the band saw to me in an awkwardly emotional way. I simply don't have the words to convey just how important this saw is to me when it comes to cutting thick metal in an almost straight line. I tear up just thinking about it. Just look how easy a job like this is with a band saw and think about the horrible alternative: using a hack saw.
Oh, the horror!
Just look at that! Look at the ease with which I was able to make such a beautiful cut! Why, there's nothing that saw can't do!
Oh, wait.
Yes there is.
It can't cut this:
Well, it could, but not where I need the cut to be. I felt so... betrayed. Abandoned. Cast aside like an easy prom date. In a desperate search for a rebound relationship, I tossed away my pride and returned to the saw that had done oh so much wrong to me in the past. The very saw I swore I'd never touch again. The hack saw. Why, even its name is repulsive to me. Hack! What kind of brutal name is that??
The shame that I felt - it was horrible!
Then, just a few short moments later, all was forgiven. Here was yet another of those situations that just screamed for the flexibility of the wonderful band saw. The idea was to cut the center hoop out of these hinges.
Piece of cake!
Once the center hoop was out of the way, a #30 hole was to be drilled in one of the corners. It would be used to hold the hinge against the part to which it was ultimately to be attached while the remainder of the holes were match drilled. I have a scrap of wood that I use to drill into to keep the bit from cutting through the blanket on my work bench. Apparently a vandal had gotten into my hangar in my absence and left her mark on my drilling board.
Awwww. Isn't that sweet??
It didn't stop me from adding new holes to the board, though. Ya gotta be tough to survive in my shop!
With the first hole drilled, I clecoed the hinge onto the part. It was ready to be clamped and match drilled.
There were more hinges to be cut, drilled, clecoed, clamped, and drilled some more. There were two that went into the seat backs about a third of the way down from the top. These were harder to clamp since they were so far from the edges, so I cleverly grabbed a piece of scrap 2x4 to support the seat backs and hinge together as I drilled through them.
That was one of those brilliant ideas I get that work fabulously right up until the moment that they don't. I guess I should have used a little longer piece of 2x4. Can you guess where the edge of the 2x4 was?
With thoughts of expensive shipping charges for a piece of replacement hinge running through my mind, I took the mangled part over to the vise to see if I would squeeze it back into shape. The vise got it close to straight, after which I made final adjustments just as if it was a tiny, easily bent longeron.
Clecoed back into place, you can hardly tell that it had been molested by an incompetent klutz.
Everything having been cut, drilled, clamped, drilled, mangled, de-mangled, and clecoed back into place, it was time for the riveting. This was one of the rare cases when Van's had a strongly held opinion on the topic of rivet direction. They insisted that the manufactured head be on the outside.
Those get set aside while the seat backs themselves get those hefty angle braces from the first step clecoed on. There were rights and lefts and fronts and backs involved, it was starting to get dark, rainy, and cold all at once, and I was hungry. Not to mention emotionally drained. I figured it might be a good idea to head home and come back for the final riveting when I could take a fresh look at the assemblies and make sure everything is where it belongs.
Well, no. They're pretty easy. Or should be, anyway, but we all know how these things go.
It started out well. All I had to do was cut the corners off of some hefty piece of angle aluminum. This is the kind of job that always endears the band saw to me in an awkwardly emotional way. I simply don't have the words to convey just how important this saw is to me when it comes to cutting thick metal in an almost straight line. I tear up just thinking about it. Just look how easy a job like this is with a band saw and think about the horrible alternative: using a hack saw.
Oh, the horror!
Just look at that! Look at the ease with which I was able to make such a beautiful cut! Why, there's nothing that saw can't do!
Oh, wait.
Yes there is.
It can't cut this:
Well, it could, but not where I need the cut to be. I felt so... betrayed. Abandoned. Cast aside like an easy prom date. In a desperate search for a rebound relationship, I tossed away my pride and returned to the saw that had done oh so much wrong to me in the past. The very saw I swore I'd never touch again. The hack saw. Why, even its name is repulsive to me. Hack! What kind of brutal name is that??
The shame that I felt - it was horrible!
Then, just a few short moments later, all was forgiven. Here was yet another of those situations that just screamed for the flexibility of the wonderful band saw. The idea was to cut the center hoop out of these hinges.
Piece of cake!
Once the center hoop was out of the way, a #30 hole was to be drilled in one of the corners. It would be used to hold the hinge against the part to which it was ultimately to be attached while the remainder of the holes were match drilled. I have a scrap of wood that I use to drill into to keep the bit from cutting through the blanket on my work bench. Apparently a vandal had gotten into my hangar in my absence and left her mark on my drilling board.
Awwww. Isn't that sweet??
It didn't stop me from adding new holes to the board, though. Ya gotta be tough to survive in my shop!
With the first hole drilled, I clecoed the hinge onto the part. It was ready to be clamped and match drilled.
There were more hinges to be cut, drilled, clecoed, clamped, and drilled some more. There were two that went into the seat backs about a third of the way down from the top. These were harder to clamp since they were so far from the edges, so I cleverly grabbed a piece of scrap 2x4 to support the seat backs and hinge together as I drilled through them.
That was one of those brilliant ideas I get that work fabulously right up until the moment that they don't. I guess I should have used a little longer piece of 2x4. Can you guess where the edge of the 2x4 was?
With thoughts of expensive shipping charges for a piece of replacement hinge running through my mind, I took the mangled part over to the vise to see if I would squeeze it back into shape. The vise got it close to straight, after which I made final adjustments just as if it was a tiny, easily bent longeron.
Clecoed back into place, you can hardly tell that it had been molested by an incompetent klutz.
Everything having been cut, drilled, clamped, drilled, mangled, de-mangled, and clecoed back into place, it was time for the riveting. This was one of the rare cases when Van's had a strongly held opinion on the topic of rivet direction. They insisted that the manufactured head be on the outside.
Those get set aside while the seat backs themselves get those hefty angle braces from the first step clecoed on. There were rights and lefts and fronts and backs involved, it was starting to get dark, rainy, and cold all at once, and I was hungry. Not to mention emotionally drained. I figured it might be a good idea to head home and come back for the final riveting when I could take a fresh look at the assemblies and make sure everything is where it belongs.
Saturday, October 16, 2010
Simplifying the equation
Here's the equation that's been bothering me:
X + Y = ???,
where X = Will This Airplane Fly and Y = Can I Fly This Airplane?
Granted, it's a year away at least, but it will have to happen eventually. There will inevitably come a day when I have to fly this thing, and it's apparently never to early to start worrying about it. I wouldn't call it butterflies in the stomach at this distant point, but pupae in the belly wouldn't be too far off the mark.
I simplified the equation today. There will still be worries over the fundamental airworthiness of the completed airplane, but at least I will know for a fact that I can fly it. Today I flew a little more than an hour in the left seat of an RV-12 and made a total of three takeoffs and landings. As a bonus, I also made a fourth landing approach and a go-around. For practice, like. Or so I would have you believe.
In what has to me one of the most masterfully created win-win deals of the young century, I offered to assist a sort-of local RV-12 owner with an introduction to the operation of his Garmin 496 GPS in exchange for a little more time riding around and getting familiar with the flying qualities of the -12. He flew up from Lancaster to pick me up at Bolton and while we were chatting on the ramp in front of the tower, he shifted over to the right side and offered me the Captain's position. Yowza!
Before we started the engine, he gave me a quick tour of the Dynon D-180 so I'd know where to look for interesting tidbits of trivia such as our altitude above the ground and our velocity through the cool fall air. Good stuff to know, those things. The increased level of complexity and sophistication over the more pedestrian mechanical equipment in my RV-6 was in stark contrast to the amazing simplicity of engine management. Time to start the engine? Fine, show me the mixture knob. What do you mean, "there isn't one?" How can that be? Okay, fine. Turn the key? Piece of cake. Whoa! I was expecting to click through left mag, right mag, both mags, and then into 'start'. The last thing I expected was to turn the key straight into 'start'. And wow, it sure does start easy, doesn't it?
Taxiing was a little odd too. Rather than the steerable tailwheel I'm used to, there's just a castering wheel out front. Pressing the rudder pedals has no effect whatsoever on steering. No problem, though. I adjusted right quickly to getting turns started with a little jab at the brakes and stopped with a little jab at the other brake. At the end of the runway, I received a briefing on how to perform the takeoff with the least amount of stress on the nose wheel. The idea was to hold the stick back as I fed power in, and not be surprised when the nose lifted almost right away. Once it did, I was to lessen the nose-up stick and let the nose kind of find its own level. The plane would fly away on its own when it was ready. It sounded a little complicated, but in the event it was quite simple. It was a good thing that I had been forewarned that it would feel like I was going to bounce the tail on the runway with the extreme feeling nose up attitude or I would have panicked and plopped the wheel right back down onto the runway.
I fed the throttle in slowly, but even still it was only a matter of a few hundred feet before we were climbing away from the runway. I have no numbers regarding climb performance to share, unfortunately. I sure that data was available on the display somewhere, but as with the rest of the performance data I found it much more difficult to deduce values from a simply glance like I can with my old clock face gauges. I can tell you this: it was slower than in the RV-6. I knew that would be the case going in, though. It was not a surprise.
I was ready for the light aileron forces, having experienced them in my previous ride, but this time around I realized that the -12 is actually lighter in aileron than the -6. It's actually what I would describe as nimble. As we were climbing away from Bolton, I spent a few minutes explaining how to enter a destination into the GPS. With MadCo firmly locked in, I also took the liberty of reconfiguring the GPS screen to what I consider to be a more useful page setup. I like to split the screen between the moving map and the HSI direction indicator. I think it's a more natural way to look at it for old school pilots.
As we approached MadCo, I became increasingly aware of one thing about the RV-12 that I don't like. More specifically, it's something about the Rotax engine. For some reason that I'm sure would make perfect sense to somebody like a trial lawyer, there is a very strong spring on the throttle that is perpetually trying to pull the throttle knob to the full throttle position. That's all well and good for those times when you want to blast around at full bore, but for the rest of the time it's a right bugger. You see, to keep the throttle from working its way forward, you have to lock the friction control on the throttle down as tight as it will go. That makes power changes somewhat of a struggle. Not knowing any better, I loosened the friction and pulled back the throttle for our descent into the landing pattern. Imagine my surprise when I noticed a couple of minutes later that we not only weren't descending, but weren't slowing down either. The throttle had returned to the higher power position of its own volition. I was to be mildly irked by this behavior for the rest of the flight.
We entered a left downwind to runway 27 and were confronted by the challenge of my first landing with a wind that was blowing directly from.... the west. Right down the runway. What could be easier! As I dropped the flaps (accomplished quite quickly in the -12 by virtue of a flap lever rather than the glacially slow electric flaps of my -6) I hardly noticed any nose down movement at all. Lowering the flaps in the -6 has a far more pronounced influence on the trim. In subsequent landings I would notice that there is a pitch trim change required when lowering the flaps in the -12, but it's minimal. What's far more noticeable is how much heavier the ailerons get when the flaps are down. I don't know if that's by design or just a lucky fluke, but it adds a nice feeling of stability in the landing pattern.
I came down final at 65 - 70 knots and entered the flare at 65 knots. I deliberately flew a much shallower glide path than I do in the -6, correctly thinking that the -12 probably wouldn't be able to lose altitude as quick and easily as I can in the -6. I found out later that while it doesn't come down quite as rapidly as the -6, it is still pretty capable of coming down when you need it to. As I flared over the runway, I was pleasantly surprised at how much more feel I had than in the -6. With the -12, I could move the stick quite a bit in pitch with minimal yet predictable changes in the landing attitude of the plane. The -6 is, in comparison, very twitchy in the flare. The least little movement has a tremendous affect on the attitude of the plane, and in consequence can cause all kinds of embarrassing bounces and oscillations. At the end of the day, it came down to this: I greased all three of my landings, at least on the Richter scale that I use for grading landings in the -6.
I mentioned a go-around earlier. After MadCo we headed over to Circleville to try a crosswind landing. Without the wind coming right down the runway to abate our ground speed, I ended up high and fast on short final. I punched in a bootful of right rudder and held the wings level with left aileron and we dropped down like a brick, but I still felt that an awful lot of runway was sliding behind us and the plane wasn't perceptibly slowing. Discretion being the better part of valor (and me not wanting to abuse the generosity of my host), I poured on the coal and took us around for another try. Better attuned to the weather conditions and the performance of the plane, I squeaked on the second attempt. Two for two, if you don't count the go-around. Call that one a mulligan.
By the time we got back to Bolton, I was completely comfortable in the airplane. While it will take time to adjust to a 110 knot cruise speed, I will quickly learn to love the 5 gallon per hour fuel flow. The benign flight qualities will please, but the bouncing around that comes with the light wing loading will take some adjustment. I was again surprised at how quiet and smooth the engine is and how comfortable the seats are. And the improvement over the already exemplary visibility of the RV-6 is amazing.
All in all, I can say in all honesty that the RV grin that I wore for the rest of the afternoon was well earned by that wonderful little airplane.
X + Y = ???,
where X = Will This Airplane Fly and Y = Can I Fly This Airplane?
Granted, it's a year away at least, but it will have to happen eventually. There will inevitably come a day when I have to fly this thing, and it's apparently never to early to start worrying about it. I wouldn't call it butterflies in the stomach at this distant point, but pupae in the belly wouldn't be too far off the mark.
I simplified the equation today. There will still be worries over the fundamental airworthiness of the completed airplane, but at least I will know for a fact that I can fly it. Today I flew a little more than an hour in the left seat of an RV-12 and made a total of three takeoffs and landings. As a bonus, I also made a fourth landing approach and a go-around. For practice, like. Or so I would have you believe.
In what has to me one of the most masterfully created win-win deals of the young century, I offered to assist a sort-of local RV-12 owner with an introduction to the operation of his Garmin 496 GPS in exchange for a little more time riding around and getting familiar with the flying qualities of the -12. He flew up from Lancaster to pick me up at Bolton and while we were chatting on the ramp in front of the tower, he shifted over to the right side and offered me the Captain's position. Yowza!
Before we started the engine, he gave me a quick tour of the Dynon D-180 so I'd know where to look for interesting tidbits of trivia such as our altitude above the ground and our velocity through the cool fall air. Good stuff to know, those things. The increased level of complexity and sophistication over the more pedestrian mechanical equipment in my RV-6 was in stark contrast to the amazing simplicity of engine management. Time to start the engine? Fine, show me the mixture knob. What do you mean, "there isn't one?" How can that be? Okay, fine. Turn the key? Piece of cake. Whoa! I was expecting to click through left mag, right mag, both mags, and then into 'start'. The last thing I expected was to turn the key straight into 'start'. And wow, it sure does start easy, doesn't it?
Taxiing was a little odd too. Rather than the steerable tailwheel I'm used to, there's just a castering wheel out front. Pressing the rudder pedals has no effect whatsoever on steering. No problem, though. I adjusted right quickly to getting turns started with a little jab at the brakes and stopped with a little jab at the other brake. At the end of the runway, I received a briefing on how to perform the takeoff with the least amount of stress on the nose wheel. The idea was to hold the stick back as I fed power in, and not be surprised when the nose lifted almost right away. Once it did, I was to lessen the nose-up stick and let the nose kind of find its own level. The plane would fly away on its own when it was ready. It sounded a little complicated, but in the event it was quite simple. It was a good thing that I had been forewarned that it would feel like I was going to bounce the tail on the runway with the extreme feeling nose up attitude or I would have panicked and plopped the wheel right back down onto the runway.
I fed the throttle in slowly, but even still it was only a matter of a few hundred feet before we were climbing away from the runway. I have no numbers regarding climb performance to share, unfortunately. I sure that data was available on the display somewhere, but as with the rest of the performance data I found it much more difficult to deduce values from a simply glance like I can with my old clock face gauges. I can tell you this: it was slower than in the RV-6. I knew that would be the case going in, though. It was not a surprise.
I was ready for the light aileron forces, having experienced them in my previous ride, but this time around I realized that the -12 is actually lighter in aileron than the -6. It's actually what I would describe as nimble. As we were climbing away from Bolton, I spent a few minutes explaining how to enter a destination into the GPS. With MadCo firmly locked in, I also took the liberty of reconfiguring the GPS screen to what I consider to be a more useful page setup. I like to split the screen between the moving map and the HSI direction indicator. I think it's a more natural way to look at it for old school pilots.
As we approached MadCo, I became increasingly aware of one thing about the RV-12 that I don't like. More specifically, it's something about the Rotax engine. For some reason that I'm sure would make perfect sense to somebody like a trial lawyer, there is a very strong spring on the throttle that is perpetually trying to pull the throttle knob to the full throttle position. That's all well and good for those times when you want to blast around at full bore, but for the rest of the time it's a right bugger. You see, to keep the throttle from working its way forward, you have to lock the friction control on the throttle down as tight as it will go. That makes power changes somewhat of a struggle. Not knowing any better, I loosened the friction and pulled back the throttle for our descent into the landing pattern. Imagine my surprise when I noticed a couple of minutes later that we not only weren't descending, but weren't slowing down either. The throttle had returned to the higher power position of its own volition. I was to be mildly irked by this behavior for the rest of the flight.
We entered a left downwind to runway 27 and were confronted by the challenge of my first landing with a wind that was blowing directly from.... the west. Right down the runway. What could be easier! As I dropped the flaps (accomplished quite quickly in the -12 by virtue of a flap lever rather than the glacially slow electric flaps of my -6) I hardly noticed any nose down movement at all. Lowering the flaps in the -6 has a far more pronounced influence on the trim. In subsequent landings I would notice that there is a pitch trim change required when lowering the flaps in the -12, but it's minimal. What's far more noticeable is how much heavier the ailerons get when the flaps are down. I don't know if that's by design or just a lucky fluke, but it adds a nice feeling of stability in the landing pattern.
I came down final at 65 - 70 knots and entered the flare at 65 knots. I deliberately flew a much shallower glide path than I do in the -6, correctly thinking that the -12 probably wouldn't be able to lose altitude as quick and easily as I can in the -6. I found out later that while it doesn't come down quite as rapidly as the -6, it is still pretty capable of coming down when you need it to. As I flared over the runway, I was pleasantly surprised at how much more feel I had than in the -6. With the -12, I could move the stick quite a bit in pitch with minimal yet predictable changes in the landing attitude of the plane. The -6 is, in comparison, very twitchy in the flare. The least little movement has a tremendous affect on the attitude of the plane, and in consequence can cause all kinds of embarrassing bounces and oscillations. At the end of the day, it came down to this: I greased all three of my landings, at least on the Richter scale that I use for grading landings in the -6.
I mentioned a go-around earlier. After MadCo we headed over to Circleville to try a crosswind landing. Without the wind coming right down the runway to abate our ground speed, I ended up high and fast on short final. I punched in a bootful of right rudder and held the wings level with left aileron and we dropped down like a brick, but I still felt that an awful lot of runway was sliding behind us and the plane wasn't perceptibly slowing. Discretion being the better part of valor (and me not wanting to abuse the generosity of my host), I poured on the coal and took us around for another try. Better attuned to the weather conditions and the performance of the plane, I squeaked on the second attempt. Two for two, if you don't count the go-around. Call that one a mulligan.
By the time we got back to Bolton, I was completely comfortable in the airplane. While it will take time to adjust to a 110 knot cruise speed, I will quickly learn to love the 5 gallon per hour fuel flow. The benign flight qualities will please, but the bouncing around that comes with the light wing loading will take some adjustment. I was again surprised at how quiet and smooth the engine is and how comfortable the seats are. And the improvement over the already exemplary visibility of the RV-6 is amazing.
All in all, I can say in all honesty that the RV grin that I wore for the rest of the afternoon was well earned by that wonderful little airplane.
Lap Dancing
I only got out to the hangar once during the week, and that was only to make sure that everything was ready to go for the final riveting of the tailcone. There were two lower side skins that needed to be installed. That sounded easy enough, but as with all things tailcone-to-fuselage, the devil is in the lapping. The parts were to "underlap the side skins, overlap the tailcone, and underlap the belly skin."
Wow! That's more laps than the Coca-Cola 600! These particular skins had stiffeners molded into their edges in the same way the tailcone skins did, so it was no simple matter to get them to fit in underneath the edges of the other skins. It took a bit of finagling to get them in and get all of the disparate rivet holes aligned.
As I was working on them, I couldn't help nervously casting glances at some of the other areas of complex lapping where two or three different skins were layered. At one point I talked myself into removing some clecos and changing the order of things, only to have to go back and return the skins to their original order after yet another consultation of the drawings. This was all just a case of nerves, typical behavior for me when the next step to be performed will immutably lock into place large chunks of airplane. When there's no turning back, I tread lightly forward.
Unable and unwilling to put it off any longer, I had Co-pilot Rick come down and help with the final riveting. Large riveting jobs are immeasurably easier with two, especially if, as in this case, the assembly is too big to manipulate alone. In this case, the bottom rivets would be much easier to do if the fuselage could be rolled onto its side, and it's now far too heavy and unwieldy for me to do that alone without running the risk of dropping it on the floor.
It was also beneficial to have someone experienced with building these things to bounce ideas off of when the plans left us wondering about some glaring omissions. The relatively large riveting job was summed up in one sentence in the plans: "Rivet the areas common to the tailcone and fuselage." Fair 'nuff. That's what we're here for, after all. But lacking in that cogent, concise, and comprehensible edict was any mention of the holes left open that weren't common to both parts. In other words, one of the C's was missing from what I call The Four C's of Good Communications: Complete.
A complete directive would have mentioned something about the status of the holes that had been left open in the areas surrounding the common bonds. In the case of both the tailcone and the fuselage belly skins, a half dozen or so holes had been left open at the edges to allow the skins to move away from the main framework to allow the required over- and under-lapping to occur. We could see no reason at all not to go ahead and rivet those holes, but we could also see no "permission" to do so.
What to do, what to do.
We finally went with our analysis that there could not possibly be any reason for those holes to not be riveted as part of the overall joining operation. I can always drill them out later if I have to, but I don't see that happening. After you been building these things for awhile, you get a pretty good sense of these kinds of things. Well, right up until the point when you don't, anyway. I feel pretty confident about this one, though.
Wow! That's more laps than the Coca-Cola 600! These particular skins had stiffeners molded into their edges in the same way the tailcone skins did, so it was no simple matter to get them to fit in underneath the edges of the other skins. It took a bit of finagling to get them in and get all of the disparate rivet holes aligned.
As I was working on them, I couldn't help nervously casting glances at some of the other areas of complex lapping where two or three different skins were layered. At one point I talked myself into removing some clecos and changing the order of things, only to have to go back and return the skins to their original order after yet another consultation of the drawings. This was all just a case of nerves, typical behavior for me when the next step to be performed will immutably lock into place large chunks of airplane. When there's no turning back, I tread lightly forward.
Unable and unwilling to put it off any longer, I had Co-pilot Rick come down and help with the final riveting. Large riveting jobs are immeasurably easier with two, especially if, as in this case, the assembly is too big to manipulate alone. In this case, the bottom rivets would be much easier to do if the fuselage could be rolled onto its side, and it's now far too heavy and unwieldy for me to do that alone without running the risk of dropping it on the floor.
It was also beneficial to have someone experienced with building these things to bounce ideas off of when the plans left us wondering about some glaring omissions. The relatively large riveting job was summed up in one sentence in the plans: "Rivet the areas common to the tailcone and fuselage." Fair 'nuff. That's what we're here for, after all. But lacking in that cogent, concise, and comprehensible edict was any mention of the holes left open that weren't common to both parts. In other words, one of the C's was missing from what I call The Four C's of Good Communications: Complete.
A complete directive would have mentioned something about the status of the holes that had been left open in the areas surrounding the common bonds. In the case of both the tailcone and the fuselage belly skins, a half dozen or so holes had been left open at the edges to allow the skins to move away from the main framework to allow the required over- and under-lapping to occur. We could see no reason at all not to go ahead and rivet those holes, but we could also see no "permission" to do so.
What to do, what to do.
We finally went with our analysis that there could not possibly be any reason for those holes to not be riveted as part of the overall joining operation. I can always drill them out later if I have to, but I don't see that happening. After you been building these things for awhile, you get a pretty good sense of these kinds of things. Well, right up until the point when you don't, anyway. I feel pretty confident about this one, though.
Sunday, October 10, 2010
And before I knew it....
It's North meets South day. The pointy end of the airplane is attached to the tail cone. This is a process that I definitely thought to be a two man job, so I asked Co-pilot Rick if he'd be able to come by and assist. He agreed, but he had morning errands to run and wouldn't be available until the afternoon. That met my schedule perfectly; I had another brace to paint and install, and once that was done the hangar would need some serious rearranging in order to liberate the long dormant tail cone from its place of repose behind the wing spars.
As expected, that stuff took a good hour and a half. I like to have everything ready to go by the time the help shows up, so I went ahead and started on the first few pages of section 25. It didn't start auspiciously. The first page was one of those that I am half convinced are intended as very dry jokes by the folks at Van's. If that's not the case, then I anxiously await someone from Van's telling me with a straight face that they believe that we can actually bend things down to an accuracy of one degree.
It reminds me of an apocryphal story I read recently. Back in the days when airliners had navigators of the human variety, it was practice for the navigator to pass heading corrections up to the pilot on a slip of paper. A very precise navigator once passed forward a note instructing the pilot to change heading one degree to the right. The irked pilot sent the note back with an added note telling the navigator that there was no way that he could fly to within one degree of heading. The navigator replied by sending a note up front telling the pilot to turn to an alternative heading of ten degrees to the right. The pilot turned around in his seat and gave the navigator a thumbs-up, as if to say "That's more like it."
Two minutes later the navigator sent up another note: "Turn nine degrees to the left."
Yeah, I think this is like that.
The way I translated these instructions was "bend these a little bit. Bend those a little bit more."
The idea of those bends is to open the top edge skins of the tail cone so that they will slide over the aft bulkhead flanges of the upper fuselage. With the tail cone positioned just behind the fuselage, I could see how much bending would be required to clear the bulkhead.
It was pretty easy to bend the tabs up. And yes, that's dust on the tail cone. It's been sitting in the back of the hangar since February.
I inched the tail cone closer to the fuselage by sliding it forward on the sawhorses supporting it. The tail cone is very light and it was easy to get it into position. The process of joining starts with the bottom skins. The front of the tail cone bottom skin has to slide between the back edge of the fuselage belly skin. I moved the tail cone skin higher and lower in relation to the fuselage belly skin by moving one of the sawhorses supporting the tail cone further forward or backward until it looked about right.
I incrementally moved the tail cone closer until the skins started to mesh.
I wasn't too surprised when I finally met resistance. I was a little surprised at the source of it, though. This was never going to work! Somehow I'd have to hold those tail cone skins down while simultaneously moving the tail cone forward.
I had to reach into the tail cone through the baggage bulkheads to push the skin down with one had while using the other two (Yeah, I know. That's what the whole job was like - one hand short) to move the tail cone forward. It wasn't long before I ran into a similar problem with the side skins. I addressed that through the clever use of a cleco.
Then I encountered a real problem. The book says that skins should overlap from front-to-rear and from top-to-bottom. It says nothing about a tie-breaker in the case where either could be accomplished, but not both. Fortunately there is a pretty good drawing on a later page that shows that the correct way is to give primacy to a front-to-rear overlap.
Then, yet another problem. I couldn't figure out how to get this skin to stay outside the flange on the bulkhead.
That too was accomplished with the use of three hands and a cleco.
Clecos also came in handy when three pieces of skin had to be meshed together.
Finally, after what seemed like hours of making tiny little adjustments (because it was hours of making tiny little adjustments) and incremental progress, I crawled underneath and put in the first cleco.
Followed by a whole lot more!
For a change of pace, the plans then had me install the should harness mount. That was easy!
Unfortunately, while I was up on the top clecoing in the should harness mounts I couldn't help but notice that I had what looked to be an insurmountable problem with the top brace. It had pulled the baggage bulkhead forward when it was riveted in and it looked like there was going to be no possible way to move the bulkhead back enough for the holes to align with the tail cone.
I figured I had to try, though. I got up on a stool and stepped into the fuselage (for the first time!!) to hold it in place while I yanked on the roll bar as hard as I could.
Amazingly, I was able to pull it far enough to get the corner of a cleco in one of the holes and use my patented Cleco Coercion(tm) method to get the holes aligned.
And before I know it, the tail cone was joined to the fuselage. I guess it was a one man job after all!
Here's the victory pose.
That was enough for the day, so I pushed Papa back in and prepared to head home. It's getting pretty crowded in the Schmetterling hangar!
And the RV-12 is starting to look a lot like an airplane!
I may still have Rick come over to help. There are a lot of rivets to install yet and it might go easier if the newly embiggened fuselage can be rolled on its side for better access to the bottom.
As expected, that stuff took a good hour and a half. I like to have everything ready to go by the time the help shows up, so I went ahead and started on the first few pages of section 25. It didn't start auspiciously. The first page was one of those that I am half convinced are intended as very dry jokes by the folks at Van's. If that's not the case, then I anxiously await someone from Van's telling me with a straight face that they believe that we can actually bend things down to an accuracy of one degree.
It reminds me of an apocryphal story I read recently. Back in the days when airliners had navigators of the human variety, it was practice for the navigator to pass heading corrections up to the pilot on a slip of paper. A very precise navigator once passed forward a note instructing the pilot to change heading one degree to the right. The irked pilot sent the note back with an added note telling the navigator that there was no way that he could fly to within one degree of heading. The navigator replied by sending a note up front telling the pilot to turn to an alternative heading of ten degrees to the right. The pilot turned around in his seat and gave the navigator a thumbs-up, as if to say "That's more like it."
Two minutes later the navigator sent up another note: "Turn nine degrees to the left."
Yeah, I think this is like that.
The way I translated these instructions was "bend these a little bit. Bend those a little bit more."
The idea of those bends is to open the top edge skins of the tail cone so that they will slide over the aft bulkhead flanges of the upper fuselage. With the tail cone positioned just behind the fuselage, I could see how much bending would be required to clear the bulkhead.
It was pretty easy to bend the tabs up. And yes, that's dust on the tail cone. It's been sitting in the back of the hangar since February.
I inched the tail cone closer to the fuselage by sliding it forward on the sawhorses supporting it. The tail cone is very light and it was easy to get it into position. The process of joining starts with the bottom skins. The front of the tail cone bottom skin has to slide between the back edge of the fuselage belly skin. I moved the tail cone skin higher and lower in relation to the fuselage belly skin by moving one of the sawhorses supporting the tail cone further forward or backward until it looked about right.
I incrementally moved the tail cone closer until the skins started to mesh.
I wasn't too surprised when I finally met resistance. I was a little surprised at the source of it, though. This was never going to work! Somehow I'd have to hold those tail cone skins down while simultaneously moving the tail cone forward.
I had to reach into the tail cone through the baggage bulkheads to push the skin down with one had while using the other two (Yeah, I know. That's what the whole job was like - one hand short) to move the tail cone forward. It wasn't long before I ran into a similar problem with the side skins. I addressed that through the clever use of a cleco.
Then I encountered a real problem. The book says that skins should overlap from front-to-rear and from top-to-bottom. It says nothing about a tie-breaker in the case where either could be accomplished, but not both. Fortunately there is a pretty good drawing on a later page that shows that the correct way is to give primacy to a front-to-rear overlap.
Then, yet another problem. I couldn't figure out how to get this skin to stay outside the flange on the bulkhead.
That too was accomplished with the use of three hands and a cleco.
Clecos also came in handy when three pieces of skin had to be meshed together.
Finally, after what seemed like hours of making tiny little adjustments (because it was hours of making tiny little adjustments) and incremental progress, I crawled underneath and put in the first cleco.
Followed by a whole lot more!
For a change of pace, the plans then had me install the should harness mount. That was easy!
Unfortunately, while I was up on the top clecoing in the should harness mounts I couldn't help but notice that I had what looked to be an insurmountable problem with the top brace. It had pulled the baggage bulkhead forward when it was riveted in and it looked like there was going to be no possible way to move the bulkhead back enough for the holes to align with the tail cone.
I figured I had to try, though. I got up on a stool and stepped into the fuselage (for the first time!!) to hold it in place while I yanked on the roll bar as hard as I could.
Amazingly, I was able to pull it far enough to get the corner of a cleco in one of the holes and use my patented Cleco Coercion(tm) method to get the holes aligned.
And before I know it, the tail cone was joined to the fuselage. I guess it was a one man job after all!
Here's the victory pose.
That was enough for the day, so I pushed Papa back in and prepared to head home. It's getting pretty crowded in the Schmetterling hangar!
And the RV-12 is starting to look a lot like an airplane!
I may still have Rick come over to help. There are a lot of rivets to install yet and it might go easier if the newly embiggened fuselage can be rolled on its side for better access to the bottom.
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