Building a Sling TSi in Connecticut
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Right after FAR 91.107 (a), where we are admonished to wear our seat belts nice and snug for the flight, there should be a requirement that all pilots MUST make a Haj to AirVenture. At least once. Preferably, the trip should be done in a homebuilt, but anything older than 1982, with a hodgepodge of instrumentation and dingy spartan interior would be acceptable. Its all about the spirit.
Making it through the torturous Fisk Arrival in a single engine-whatever makes one feel a bit more competent, and a bit happier with one’s self. That same sort of rush you get after getting through yet another flight review. Maybe they should make it a way to fulfill a flight review, particularly if they flew the arrival using foggles. You still have that nice adrenaline boost when you get on the ground, which is good, as it puts you in the proper frame of mind for enjoying the whole raucous thing.
When we made our first Fisk Arrival, we had no intention to do anything other than to have a Max Blast Full Strength Turbo Charged Inter-cooled Good Time at AirVenture, Plus make a side trip to Neenah to visit Our Aunt and Uncle. There was absolutely no intention of building a Sling, we haven’t even heard of one before the afternoon of July 21, 2019.
That afternoon the Mattituck Gold IO-360 under our cowling dragged Cessna N1226F along with its droning thrum, as we moseyed at a stately 110 KTS out of Janesville, 4500 feet above the sun splashed Wisconsin country side, the sweet smell of crops wafting up in the late afternoon sun. Finally, we were inbound to Oshkosh and AirVenture. It was lovely. We were simply excited about the chance to have fun, attend some workshops, exhibits and airshows. There would be days of it, plus a visit to Our Aunt and Uncle.
The afternoon before that, we had flown west all the way from Westerly Rhode Island, overnighting in Youngstown Ohio. The next day, we continued on, making it all the way to southern Wisconsin. But then, a massive, cruel black hearted storm grounded us in Janesville. We had just gassed up in Gary Indiana when we saw the storm over 100 miles away in Minnesota on the Foreflight GPS thingy. Ugh. Perhaps, with a bit of expeditious haste, we could make Oshkosh and have all Sunday to get the visit with our Aunt and Uncle done before the show. Everything would fit together, nicely. That simply was not to be. When we were cruising along north of Chicago the storm was raging closer and closer to the north, west and east of OSH. Like a giant pincer it was closing in on Whitman field, closing steel trap fast. It was a matter of minutes it seemed that it got so bad that there was no choice, we diverted to Janesville, where we joined dozens of other airplanes flocked together on the ramp, some tied down others not, in meager succor from the raging storm to the west. We all stared in nervous apprehension for an hour as the planes strained tiedowns, and nipped at chocks, while the wind blasted through and rain the thrashed down.
As the storm moved on, Our fear turned to disappointment on finding the passing fury had closed Whitman field for the night. The staff at the Janesville airport did beyond the best of mortals finding lodgings for everyone for that night. For us, we had our lodging gem, a cozy unairconditioned discounted room at a Motel 6, with its sumptuous made-over bomb shelter décor (The cold laminate flooring was particularly welcoming under bare feet). It was perfect, even the light was on just like Tom Bodell promised. Nothing to do but wait and sleep, under the wretched light.
At 3 O’clock in the afternoon the next day, Whitman field was declared open. We joined the invading swarm of pilots and planes briskly plying north towards Green lake, where we would join yet hundreds more funneling their way to Whitman via the Fisk arrival. The drenching rain and blasting wind of the day before were but a memory now, as we negotiated the whole Fisk Arrival process, landing on the yellow dot on runway 36. At long last, We were going to have fun, lots of double stuffed, max blast, over the top Ice cream Sundae turbocharged fun. And visit our Aunt and Uncle. We were absolutely NOT going to build and airplane. No Siree. That would change.
We parked next to the Plane Lady and her husband Tyler who were building an RV10. They were a lovely couple who had flown all the way from Texas in their Cessna 180. You can catch a glimpse of our Snoopy’s Group flying club’s N1226F in some of her AirVenture videos. At the end of the first day, we saw the little airfoil they had made during a workshop, glinting in the late afternoon sun. That was when the seed was planted somewhere in the depths of our basal stems. By our third and last day on the grounds, we had migrated through all the other cool flying related stuff to the homebuilts. Yessir. That was what did it. We sat in an RV10, the Interior was a bit spartan, and the control stick was loose, both of which, I suppose, could be easily rectified with some strategically installed cloth and plastic for former, and even more strategic wrenching for the latter. And then the Sling TSi. Pulled rivets. Aggressive styling. Slick backed tail. A gas sipping Rotax 915si. The RV 10 looked, well…rather church lady, albeit at 200 mph. We also visited the Velocity. We should build a Sling TSi.
It is a lot like being a first-time parent, where you are getting a nursery ready, painting the room the right shade of blue or pink, new crib, Canadian rocker, you know, The Treatment. of course, In this case, the garage was getting The Treatment. For us, it was a major undertaking. First, over fifteen years’ worth of sawdust, metal and plastic scraps, paint, car parts, bike parts, special projects, tools and what-not strewn, tucked, tossed, positioned, piled, ensconced, splattered and shoved in all sorts of nooks and crannies, It all had to be cleared out. We needed plenty of space for the build, and need to be able to put at least of our cars in the garage at least some of the time while we were doing this. That was of utmost importance.
Imagine laying in a snowbank while changing the oil in an aging minivan pushing north of 260,000 miles in a grinding cold winter day. That sucks. As in contents of a septic tank being evacuated sucks. Obviously, not only would we need space for working on the plane, we would need to be able to park a car inside at least some of the time. To paraphrase King George the 43rd, we would need to do some “strategerizing” to make this happen.
Right. We developed some strategery. We would have to clean up the garage full of squalor…So we cleaned up the squalor. ‘Nuff said! Well, maybe not: Let’s just say a high-powered leaf blower can be very useful indeed when cleaning out a garage, Blast away my kiddies!
Next came the more exciting part of the garage make over. We have the same storage and work space problem all home owners have. At 22 ft by 22 ft, our garage is a wee bit space challenged, even as a 2-car garage. We did have one nice advantage. with the expansively helpful benefit from putting an over the garage bonus room in our house, we ended up with 11-foot ceilings in our garage. It puts a nice capitol B in bonus on that one. The only thing to do now is colonize the extra space in first world style. Fortunately, part of the exploitation was already done. Not long after we moved in, we installed some heavy duty shelves using custom steel brackets our neighbor made and some 2X10s from River Head Building Supply. Awesome!! Furthermore, later on we installed an Electric Kayak rack. Double Awesome!!
We set to it. First, we cleared 15 years bunk and junk and springs and things off the shelves and stored it safely away in other safe places. We now had a nice spot for the yet to be completed empennage. That left the wings. For those, we had our Electric Kayak Rack (EKR, This is aviation, we have to have a few acronyms). About 4 years ago, we decided to get kayaks. I love Kayaks, you only need one paddle instead of two like a row boat, that makes it only half as complicated to operate. Its kind of like a jet engine (Or a Sling!) with one power control instead of piston aircraft’s two or three. Sorry, I digress.
The EKR had a pair of Unistrut lengths which hung from sheaves mounted to the ceiling on either side of the garage door opener. At the other end of business was a genuine Harbor Fright winch. A set of carefully positioned sheaves guided the rope from the winch to the two pieces of Unistrut. The kayaks were strapped to the Unistrut, and when you ran the winch, the kayaks would lift up into the top of the garage. It was really fun to watch.
Now the conversion. We kicked the kayaks out to a rack behind the garage, love can be so fleeting. We took the 2 pieces of Unistrut from the EKR and a new piece from Granite Electric, and with a couple hours of cutting and grinding later we had nice 4 x 8m frame. We covered that with a sheet of ½ inch AC from Riverhead, making a nice light weight but sturdy 4×8 platform. The real trick was doing up all the ropes that lifted the Platform. We redid the rigging, positioning the sheaves so that the 4 ropes lifted the corners of the platform. Once we had the rope reconnected to the winch and platform, we had a brand spanking new ESWS, or Electric Sling Wing Sling!
Next, an ensemble of furniture. We started with the work benches. The EAA has a lovely practical design, a cleaver arrangement where each leg was a pair of 2X4s cut and nailed/glued together which support a shelf and top. A lovely functional design. We didn’t use it.
Instead, we came up with a cunning plan. First, we made a bee line to Riverhead Building Supply which is often cheaper than Home Cheato. It’s a great place, the guys know what a 2X4 is. You can literally drive your minivan right into the store, right up to the plywood pile without anyone so much as raising an eye. Just act like you know what you are doing, is all I’m sayin’. We picked up a couple of sheets ¾” AG, ¾” birch and maple plywood and twelve (12) 2X4’s. and we got a whole bottle of glue.
The design in the EAA site has a shelf that is 7-inch shorter than the top to accommodate the 2X4 legs. To get a longer shelf, we made legs from plywood. First, we cut four 4” wide strips from the AC sheet length-wise using our abused and ancient table saw. Then we cut two 39- inch pieces from each strip. We made the flour legs by gluing 2 pieces together at 90⁰ to form a butt joint. (Ha Ha! I wrote the word “butt”! hee hee hee!) We also screwed the pieces to hold them while they dried.
We did the platforms the same way they show doing the top platform in the EAA plans: http://www.eaa1000.av.org/technicl/worktabl/tablefig.htm . One would be the top, the other a shelf. After they were made, the plywood legs were glued and screwed to the corners of each frame, one frame was flush with ends of the plywood legs, the other was glued and screwed 8in from the other end of the legs.
The top piece of AC was cut to match the overall dimensions including the legs. That was glued and screwed down. We covered that with the Birch and Maple plywood, glued and clamped down, which made the top a more heavy-duty 1½ in thick. Plus, the birch is a much smoother surface than rough AC or CDX grade plywood. The shelf was a piece of AC that matched the dimensions of the 2X4 frame. Getting it to fit took some fitting, but it made a bigger shelf, nicely screwed down firmly. Finally, we added some nifty wheels, from Rockler, and used these mount brackets so we only needed one set of wheels.
The last part was the Sling Plans Holder. It would be nice to have some sort of holder for the instructions so that they don’t end up getting destroyed in by laying where ever fits the time only to get torn, soiled, or end up with a massive cup ring. Plus, they wouldn’t take up valuable bench space. After all the bench business, we had a 2-foot wide piece of AC left, and some birch and maple. We turned that into a nice Sling Plans Holder, (SPH) just look at the photo.
Week The First, Inventory. 4 hours.
Do you remember, those days before Corona (BC) long, long ago in the age of the not so great Amazon, when only the nice things like computer stuff, books, and rare artisanal shoe laces would come in boxes landing on the front steps. Things like toilet paper were not so rare then. For that, you went to the Walmart or for a smaller, deburring wheel like roll, Dollar General. Now, as the Connecticut Slingers Ministry of Public Dealings approvesthis report, you HAVE to get your toilet paper in a box from Lord Bezos… only to have it stolen from your front porch, Thanks, Corona.
On that cold February day, it really was like a throwback to those ancient days BC when our Sling TSI empennage and wing kits came. The call came the night before, a nice lady from the shipping company gave me the details, after which she declared, ”He will be there between nine AM and three PM”
She must have heard my eyes rolling in frustrated disbelief.
I gently informed her that it being a weekday, and seeing as how we, like 99.999 percent of the rest of the universe, would be at work, this was still BC, by the way.
“I can have him call you half an hour ahead if it is more convenient.”
Hmm, no thoughtful Rodin pose needed on that one. “That’s fine. “I smiled. “Thanks.”
Advance to the next day. My hands were thrusted deep into the nasty gaping maw of a piece drug testing paraphernalia, tediously assembling a teeny tiny insy winsy little bitty bit of a ferule on to a tube the thickness of the small end of a snail eyelash squashed under the main gear of a 747.
My phone rang.
I dropped my tiny little wrench, peeled off a glove, coated with whatever designer experimental pharmaceutical nastiness and pulled my phone out of my back pocket.
“You’re in the yellow house, right?” a nice happy to be of service voice from what I imagined was a middle-aged trucker, definitely not Santa Claus.
“No, I have my hands in some drug paraphernalia.”
“No I mean, You are the yellow house right?”
“Yes, that’s my house.” I could see where this was going. “Where are you now?”
“I’m right outside.”
“I asked for a 30-minute headsup.” I protested, as nasty chemical whatever started to dribble out of the teeny little tube.
“Well they don’t tell us anything from the office.”
Fortunately, he could unload the three boxes into the garage, since my wife was there to direct, and my son, whose big idea this all is, helped a bit while I finished fixing the magic box.
When I got home, the three boxes containing the wing and empennage parts were resting comfortably in the garage, a bit worn and scarified from their journey. The wooden box had a some of the wooden crosses members on the pallet broken, and one of the cardboard 4 X4, glued to the bottom of the cardboard box holding the empennage was knocked off. Hopefully the parts within the boxes would be in yet better shape.
After supper, we sat down to open our presents. Being a bit like Christmas we wanted to open all the boxes. All of them. at once. So, we did. After a few minutes pawing through all the stuff, we resorted to less efficient means of finding out what in the boxes. We did inventory. As with the other Bloggers, at the top of the pile in each box was the Multi colored instruction booklet with an inspirational photo of Wayne Toddun’s TSi on the front. The inventory list was also right on top, like a note from your mother on a pile of cookies telling you to mow the lawn first. Gawd!
Right. The Dickensian task of inventorying. Not quite like teasing apart tar encrusted old rope, but arguably just as tedious. After some piddling about, we ended up starting with the big plywood box containing the wing parts. Picking the parts out one by one, my sons unwrapped the bubble wrap and read off a part number, as I stood over our Sling Instructions Holder, flipping through the finely printed part numbers and descriptions searching for it. The bubble wrap was carefully set aside for popping later.
As for the Rivets, rivnuts, bolts, wiring and all the other little itty bitty bits, they were lovingly done up in strips of bags sealed individually like the way they do bags with the As seen on TV Bag sealer. The strips had labels like “Elevator Hardware” and “Vertical Stabilizer Hardware”. The end result is a long Dr Who Tom Baker scarf of bags and bags of little itty bitties. Each little part of each little bag of each bag-scarf was listed in the excruciatingly detailed list, and had to be accounted for. We did stop short of counting the thousands upon thousands of rivets.
Fortunately, there was some organization to it with the part numbers having relevantly chosen prefixes and the line items grouped together by component. After a couple of evenings, we had found most of the parts. There were still quite a few missing, and in a febrile fit of frustration I fired off an email to the guys in Torrance. The list was of MIAs inconceivably long, so I started going back over the parts, lowering the Electric Sling Wing Sling, pawing through all the bundles. I ended up finding them in ribs clamshelled together, and as I shucked the ribs off and found the smaller parts, the list of MIA pieces shrank, to none. We had the parts.
Sadly, there were some casualties. The wing rear spar upper skin supports were horrifically ravaged and brutalized during the trip. The photos are not for the faint of heart, however, the damage must be revealed.
With inventory complete, we carefully consigned the wing spars and skins to the shelves, and the smaller wing parts to the Electric Sling Wing Sling. Their turn for the Connecticut Slingers Treatment would come in time. For now, We turned our attention to the empennage build.
Firist week of Many Many More
Cleaning the Empennage Parts 3 hours.
What is it about doing cool stuff only happens after long, dragged out eons of dull boring tedious drudgery? Riveting parts together with our Milwaukee electric riveter is what we are all about! Instead, we got to do a whole lot of work house prep work. I mean, it’s like Middle School shop class. They make you drudge through endless hand tool dawdling before the real fun-filled electric power tool mayhem can start. But suffer through it, we must.
We begin with our account of our cleaning of the inner gizzardy parts that hopefully will never see the light of day once everything is put together. As we get started, its worth mentioning that if you have ever washed dishes, you would be well qualified for this part, and have figured it all out. If not, this will help you make your way up to a nice plum of a dish washing position. So, we will get right to it.
Simple Green Extreme Simple Green Aircraft & Precision Cleaner from Aircraft Spruce
Scrub Brushes from Cash Hardware in Mystic, CT
Mixing tubs from Tractor supply in Griswold CT
Safety wire from Aircraft Spruce
Goggles Cash Hardware in Mystic, CT
Neoprene gloves Cash Hardware in Mystic, CT
Something to sit on. Cash Hardware in Mystic, CT
Sling Parts Drying Rack (SPDR)
At the center of all this was our use of Simple green Aircraft cleaner, and is recommended by everyone that matters. It should be noted that Simple green is neither simple nor green. It has Diethanolamine, which along with coffee and aloe vera, causes cancer in the state of California. Fortunately, it doesn’t seem to cause cancer in anywhere else in the universe, and its biodegradable. There is one disappointing thing though. it was clear, NOT green. They must have forgotten to put the FDC Yellow Dye number 40 and The Blue #1 in it. Maybe they thought they had done enough with the Diethanolamine.
For parts washing, it is recommended to dilute the Simple Green, trouble is by how much?
Luckily, there was a nice guide on the jug to help with how to dilute. The guide is biased to dealing with completed Slings, but buried in the details is what was important to us.
The guide says that for Slingers that keep their Sling clean all the time, a ratio of 1:13 is supposed to keep it sparkling. It says it will not corrode as per the ASM1526B test, whatever secret Government conspiracy that is. Fascinating but irrelevant stuff.
For a thoroughly Hog pen icky Sling, Slingers should use a ratio of 1:3. In the same blurb, it says that this same ratio should be used for cleaning parts and concrete. Not sure what Sling components use concrete, but when we encounter them, we sure will give them a right good scrub.
So, a 1:3 dilution it is. Right. We went to work.
We donned our full, fashionable cleanroom bunny suits. Then we cladded our feet with full foot coverings and our heads with those sexy Hazmat hoods. We rounded out the ensemble with full positive pressure breathing regalia. Properly attired, we ventured into the positive pressure ISO Class 7 cleanroom (as defined in ISO 14644-1) via a double airlock. There, awaiting us on our freshly sanitized and derouged 316L stainless steel table, were all the sling parts carefully lined up next to a pair of NIST traceable Class II graduated cylinders on ………………..wait Wait WAIT! Stop the Tape!!!!!!
That’s NOT how it really happened, though it would have been nice and cool.
Instead, in our unpainted, home built garage, on the cold concrete floor, we glugged a whole bottle out into a mixing tub. We refilled the same jug from the kitchen sink and dumped it into the tub three times, and called it a good 1:3 dilution, Next, A rinse tub was filled with water and we were in Business!
without hesitation, t, we peeled off the plastic film from the smaller empennage gizzards and placed them in the Simple Green for a good soak. We kept in mind that each and every part may have been glanced at by none other than James Pitman, Esq, or even, just maybe, Mike Blyth himself, and thus rendered hallowed. So, we lovingly scrubbed off all the plastic and oil residue from being cut to shape, bent and coifed. Next came a slosh in the rinse water and placement on the SPDR to dry. Dead cat slingin’ easy.
The process got even stupefying easier from there. Grab a part out of Simple Green tub. Scrub, with brush, being sure to get around the prickly parts if they have any. Then rinse off in the rinse tub. Then place it on the SPDR tray to dry. For hour after hour, we scrubbed and sloshed through this WorkFare job until the last of the parts were finally drying on the trays on the SPDR.
The tubs were too small for the long parts to soak, so we just rested an end in the tub and scrubbed top to bottom, and then rinsed by scooping water from the rinse tub and pouring it over the top. it’s like washing your hair. Wet, lather, rinse, repeat, repeat repeat four hours on end.
After reading thus far, and the last three sentences in particular, you, dearest reader must be thinking, “What a dribbling Captain Obvious the one who wrote this screed is”.
Well, Just keep in mind, this is serving as part of our build record we have to give to Captain Dickson, who is in charge of the FAA at the moment. With the government involved, we have to spell it all out.
We held off on doing the skins. We would do those after we finished deburring, allodining and priming the gizzards which would take would take a while.
Next up: Deburring and dimpling.. What fun.
First week after the first week…. Deburring and dimpling the Empennage parts.
8 tedious mind-numbing monotonous hours.
Bear with us, dear reader, this is going to be a long screed.
When engaged in menial repetitive tasks, one can take some solace from knowing that throughout human existence, every epoch had jobs that were dull, boring and monotonous. Picture this: It’s the great land of Turkana, Kenya, 3.3 million years BC (Before Corona). The clink clink clink sounds of flint knapping ring out across the savannah. Hour after hour, clink clink clink, punctuated with strings of cursing from the Australopithicoid flint knappers. By evening, the sun sets over a gazelle roasting over a fire. As the meat sizzles, one of the boys pauses in his work, mops his unibrow for the umpteenth time since that afternoon, turns to his colleagues and says, “I say gentlemen, this monotony grows ever so wearisome, it makes one wish for a more speedy advent of metal tools!”
A chorus of “Here Here!” erupts amidst the flint dust covered knappers, as the gazelle patiently drips juices into the fire.
While our pithecoid relatives of yesteryear had flintknapping, today, we have deburring airplane parts. Of course, in between the two, the Wright brothers spent hours and hours stitching the wing coverings with Daddy’s sewing machine, no doubt thinking Charles Taylor had the cooler part of the enterprise. I’m sorry, we digress.
Even though deburring is but just one of the dull jobs, it is oddly enjoyable in a tedious sort of bubble wrap popping way. It is a good thing to do when you are watching the TV, chit chatting about what to do after Covid-19, or better yet, just how nice the Sling will fly.
Let’s start with the why we torture ourselves with the endeavor. The burrs prevent a good fit between the two pieces of sheet metal and over time can lead to the pieces flying off in flight creating an unsatisfactory condition. In addition to giving you a scorching paper cut, the sharp edges are where corrosion can begin its evil.
let’s see what we are dealing with close up and personal. The Lord Slingungous, High Sub Rear Commander to the left of the Minister, authorized the release of the following photos directly from the Connecticut Slingers Ministry of Truth files. Here is a burr on a straight edge and on a hole when you look at it with a microscope:
All those nasty, bumpy little bits on the edge are what you feel when you rub your finger across the edge of the sheet. They are also what makes the pieces not fit flat against one another when you rivet, and those teeny tiny pointy bits are where corrosion can get a nasty foothold. This is why burrs are very bad. Very, very bad. Definitely naughty.
To get an idea of how to deburr. We visited a fellow EAA builder working on a Bearcat, and another local EAAer building a replica P-40 for some tips. We also visited several awesome online blogs and videos, such as the episode from the brilliant and inspiring series done by Evan Burnye, The Plane Lady and this one by the Dreambuildfly guys. Lots of great stuff, so let’s add ours on to the pile.
Choosing the Weapons.
We didn’t have a 6-inch ruler like what Evan used, nor his skill, so we didn’t use one of those.
Evan also had a drill bit and one of those swivel deburring tools. We had a big drill bit left over from when we built our house. And a file whose origin is lost in annals of time, and to round out our arsenal, we had a Dremel tool. Off to a good start there.
We still needed more stuff to complement our massive suite of tools:
Avery Speed Deburr-C Sink Tool – Aircraft Spruce.
Just like the dunk and scrub from our last diatribe, deburring was done piece by piece. Grab piece from the Sling Parts Drying Rack, scratch scratch scrape scrape, twisty twist, set back on the SPDR. Dull, flintknapping tedious. For the most part, at least.
Here are the details.
Let’s start with the Straight edges. In most cases, only one side needs deburrment. This is nice, it means only half the work we thought we needed to do. For these, we used the Shaviv deburring tool. There are other tools like it which have a handle and a hook like blade that spins around in the end. This one, however, has a nice red and blue handle. You can pull the shaft out a few inches, though we didn’t, and the bits can be changed easily.
The Shaviv tool is completely and irrefutably great on the straight-aways. That said, it does need to be done carefully, or it will bind up and create more frustrating nicks which are not nice, they stress the metal out, and could lead it down a path of self-destruction.
To pull off a good Shaviv deburrment, Just hold the piece straight out away from you, place the Shaviv on the edge as close to the far end as possible, and pull the Shaviv toward you in a nice graceful motion, its fun to watch the little curly cue thingy of metal peel away leaving a nice smooth edge. Straight edges are as fun as peeling the plastic sheeting from the parts before the washing. Could do it for hours.
The Shaviv does a yeoman’s job with large holes as well, but we had to be careful, if we didn’t angle the shaviv right, we could nick the metal, and that is bad. the trick is to circle the large hole with your hand angled slightly outside the hole, and pulling the tool around the hole. Just like the straight aways, it has to be done with the right smooth moves. Got to do a video for this one.
All that said, it is all but impossible to do outside curves with the shaviv, like what you find with the inspection and access covers. Like trying to shave a gorilla head. Also, the Shaviv doesn’t do so well in the front toothy parts of the ribs. Still the flashy red and black handle fits well in the meat paw.
Let’s move on. Little holes and the way to do them. For this we used 2 different implements, the drillbit, and the deburring crank thing called the Avery Speed Deburr-C Sink Tool. Both work well, and very easily. For the drill bit, place the business end into the hole, and give it a twist. Lotto ticket scratching easy.
The Avery tool is different, though same idea, except you give it just one crank instead of a twist. Any more than that and you risk removing too much, and the rivet won’t have enough metal to grip. Both work the same, but, the lack of a proper handle on the drill bit may make your hand grow sore. Rather than whine about it, and use it as an excuse not to do any more work, switch over to the Avery cranker for a while.
So, what about the round parts like the inspection hole covers? And the teeth on the front pieces that frame the front nose of the wings and empennage pieces? And not to forget, what about the end of the straight piece the Shaviv left behind?
All of these we did with a file. for the round pieces, so we placed the piece near the edge of the bench, and file the edge lightly at an angle as you rotate the piece. The little bit left by the Shaviv on straight edges is easy with a few strokes with the file. If you can flare an airplane and reduce power while adding in cross wind correction you can do it just fine. The file also rounds the corners on the teeth parts of the nose pieces, just file back and forth lightly as you move the file around the corner. There is also another tool we used for rounding over the corners. More about that in a little bit, but first…
The following paragraph contains a spoiler alert. Just thought I would let you know.
There is one bit on the ribs that is all but impossible to get to. As the wise and astute Mike Blyth observed at 51:58 into his brilliant documentary, Wild Landings: Namibia: “It is the middle parts that are difficult.” Just as Mike did in the movie, we had to find clever ways to get to the middle parts. Our middle parts were between the teeth where there was a curved bit which made the Avery Crank, drill bit, shaviv and file useless. The Shaviv can get into the sides of the teeth, but not the back curvy bit between the teeth. The drill bit and Avery crank would slip off the curved back end, a chainsaw file may help here, but we didn’t have one.
It is times like this we turn to another wise and great DIY philosopher, The great Red Green: “When All else fails, switch to power tools!”
Our power tool of choice: a genuine Dremel tool, fitted with a chainsaw sharpening bit. Ah Yes, 120 volts of raw power spinning at 35,000 RPM BUWAH HAH HAH HAH HAH!!
To make this work, We held the Dremel cupped in our fingers, and resting our thumbs on the edge of the piece, we could maneuver the spinning bit around the difficult parts. If you have ever peeled potatoes, you will find it easy. We haven’t really tried using the Dremel for much else yet.
We spent a good 5 hours to deburr every last little hole and edge of every part. Time flies when your knapping flint.
So after all that shaviving, cranking, bit twisting, and Dremeling This is what we get:
Aren’t they lovely?
Next, We had the joy and fun of doing the dimples.
First the toys:
DRDT-2 Rivet Dimpler (Aircraft Spruce and Specialty)
Dimple Dies The small 2.8mm ones (TL-DIM-003-X-X-0 and TL-DIM-103-X-X-0) came with the kit.
Bench Grinder from Harbor fright (Yes this beast was involved)
Before we get into it, first a word of caution.
There is a bit of fun with this, and if you are not paying attention, you can get carried away with making dimples that you forget where to stop. Indeed, it happened when we were having way too much fun with it and got a bit carried away. We ended up dimpling a little too far with the inboard ribs of the elevator, and this lead to a febrile fit of worry.
We made the first of many panic calls to The Airplane Factory. The brilliant and genteel Jean D’Assonville enlightened us on the subject. He assured us there is no harm in doing too many, it’s only a bit of wasted effort. In fact, the dimpled rivets might add strength to the joint, since the dimpling provides a little more surface for the rivet to grip. That part was reassuring, but the wasted effort didn’t sit right, we certainly don’t want to do that. Even if it was fun.
So my dear reader, learn from those intrepid dimplers who dimple before you. Guard your dimpling zeal. Steal yourself. When referring to the instructions, Don’t just count the circled holes to be dimpled. Check a few times, and then mark where to stop dimpling on the part. Then check a few more times to be sure.
Let’s move on. We decided to go with the DRDT-2 for our dimpling campaign. The mechanism looked like it would be a lot more consistent with dimple quality, and the gray color complimented the gray tool rack we had in our garage, arguably the most important factor in the decision.
The DRDT-2 came with assembly required; However, it wasn’t too hard put together. We found that after it is assembled, it needs to be bolted down to the work bench as when you start to dimple, it will lean forward as you apply pressure with the handle, and possibly the 44lb DRDT-2 will fall off and hit your foot, or worse, bend the part being dimpled.
The next thing is setting it up with the dimple die. for the empennage parts we used the smaller set of dies provided. We installed the male die in the ram (the part that moves up and down with the handle), and the female die in the die receiver (The part that doesn’t). If this confuses you, the male die has the little teeny tiny knob that looks like a teeny tiny VOR ground station. Having the dies installed this way will allow you to dimple in the same direction that the rivet would be installed, which helps you not dimple in the wrong direction. Plus, when dimpling ribs, the bulk of the rib will hang downward, away from the mechanism.
With the dies in place, we had to get the ram set just right. If it wasn’t, we could scratch the work piece, or make the dimple to shallow where the rivet would stick out when it was installed. This was easier to accomplish than we thought. We found Katie, an RV-3 builder who made a nice treatise on the subject: Katies blog.
To adjust the ram, we lowered the handle down until it stops. The loosened the big nut on the ram. Next, we unscrewed the ram downward until the two dies meet. Then, we lifted the handle up, and unscrewed the ram ¾ turn. Finally, while holding the ram so it doesn’t turn, we tightened the nut, used a wrench for that. Then came the moment of truth. We tried a few test holes.
Since the male die will fit through the hole snugly, we had to be careful not to miss, but to line it up right. We found it may be easier to fit the part onto the die rather than try to lower the die into the hole, your choice. After the facile step of getting the die into the hole we simply lowered the handle until it came to a stop, then raised the handle, and admired the dimple. It was easy to do, and Repeat. We checked a few of the dimples. They didn’t fit.
We consulted the directions, which we read once already and kept for just such an occasion. We also called TAF and confirmed with Messier D’Asonville that we are supposed to drill the holes using the 3.3mm bit. (1/8”, here in People’s Republic of Connecticut). Success! We found the rivet fit snugly, and the top of the rivet was flush with the piece!
With the process mastered, We started with the frame pieces. The spars were easy enough, However, we had to mark where to stop to keep from getting carried away and going too far. The ribs were challenging. Some of the ribs did not have enough space between the hole and the web (The part that is vertical) for the die to fit. After a commensurate amount of hand wringing, we followed the experience of other builders and ground down a side of the dies using the Harbor Fright bench grinder. We wish they sent two or three sets of dies. Still, the ground down dies continued to work well, and we dimpled on.
The large skin pieces took a person and a child to do to keep the ungainly sheets from flopping all over the place and curving over the dimple receiver. The skins were also clamshelled, which added to the challenge. Never the less, We got them dimpled with tender loving care.
The DRDT-2 is the only system we used for dimpling. We can unequivocally and safely say, without any reservation whatsoever, that it was the best system we used. It was fast, simple and easy to use, the dimples were accurate, and precise. And it was flint knapping fun.
Doing the allodining and priming. Ugh. Cancer and dead brain cells here we come.
Allodining and priming empennage parts
10 hours of toxic fun
Our Dear Reader:
Many years ago, chemistry sets were real chemistry sets. They had really cool chemicals, the kind that would melt metal, fizz, or explode. Just think of it: Strontium Chloride, Sodium Cyanide, Ammonium Nitrate, Potassium Nitrate, Sulfur, powder charcoal, and for the budding nuclear weapons enthusiast, a nice little chunk of Jenny-wine Uranium.
Plenty of ingredients for some good ol’ fashioned adolescent mayhem. All gone now. Thanks to draconian regulations, unrestrained feral lawyers, and overzealous neurotic parents, the wonderful fun, art, and science of real chemistry sets of decades ago have been barbarously usurped by cartoon boxes of pretty fluids and things that make goop. It makes the well-known observation “Science is doing stuff in a lab that would be a felony to do in a garage!” sadly true.
What a sad and tragic state of affairs.
But all is not lost, we slingers can do our own chemistry fun, in our garage, in defiance of the nanny state.
What we used:
All Purpose Mixing Tub, 11 gal. / 1.5 cu. ft. – Tractor Supply
2 Gallons Bonderite M-CR 1201 AERO – Aircraft Spruce and Specialty
2 Gallons Bonderite C-IC 33 AERO – Aircraft Spruce and Specialty
AKZO NOBEL EPOXY PRIMER 2GAL – Aircraft Spruce and Specialty
6” PVC Pipe – Granite Supply (Groton CT)
6” PVC End Cap – Granite Supply
6″ x 6″ DWV PVC Female Adapter w/ raised plug- FW Webb (Waterford CT)
½” PVC Male MPT x S Adapter – Cash True Value Hardware (Mystic CT)
½” PVC Elbow – Cash True Value Hardware (Mystic, CT)
½” PVC Ball Valve – Cash Hardware
Rubber boots (Walmart, We had that kind of money)
¾” drill bit (Montville Hardware, Montville CT)
¾” NPT hole Tap (Montville Hardware)
Rubber Gloves (Home depot)
Polyethylene Plastic (Cash’s true value, Mystic CT)
And now for a chemistry lesson from our Ministry of Truth and Information. Read this next bit at night, while in bed…just before you shut out the light and go to sleep.
Aluminum Sling parts had a thin itty bitty teeny microscopic layer of Aluminum Oxide. In other words, it had been corroding, even after Mike Blyth touched it. (Mon Dieu!) To get rid of it, we have to clean and etch the part. This is a bug zapper watching fun time. When the Sling Part is lovingly placed in the dilute Bonderite C-CI 33 solution, it fizzes. What fun. The phosphoric and hydrofluoric acids eat away at the aluminum oxide, Behind the scenes we have this:
Al2O3 + 2H3PO4 -> 2AlPO4 + 3H2O
And some of this:
Al2O3 + 6HF -> 2AlF3 + 3H2O
And bubbles. Lots and lots of bubbles. The kind Lt. Don Ho (USAF ret.) sang about when he wasn’t flying C-97’s. Sorta. Only the bubbles are steam not CO2.
While all that is going on, the 2-Butoxyethanol is dissolving residual oil and gunk on the aluminum left after we cleaned the SlingPart with the Simple Green, that isn’t really green.
After all that, the Aluminum Oxide turns into bare aluminum, and the oil is gone leaving the Sling Part plain old aluminum clean and ready for the next treatment.
Next comes the allodining. When an Aluminum Sling part is gently and reverently placed in the chromic acid bath at a pH of 2, an oxidation and reduction reaction occurs between the hexavalent chromium, which is missing 6 electrons, and the 6061 aluminum Sling part. The aluminum in the Sling part gives out 3 electrons to every chromium atom, which makes the chromium tri valent and the aluminum the same:
Cr6++ Al0 → Cr3++ Al3+
Cr3++ 3 HO−→ Cr(OH)3Al3++ 3 HO−→ Al(OH)3
Meanwhile, Ferric cyanide accelerates the reaction, making the aluminum and chromium react faster and faster, like throwing gas on a fire. Next, the aluminum and chromium hydroxides mix up in the water and the whole magic sauce turns into a gel that coats the whole sling part, every nook and cranny. After a few hours drying, it is tough, and corrosion resistant, just like a Jello Knox blox that sat on a saucer under your bed for a week when you were a kid.
Jeezum Crow! that was dull. Blah Blah Blah. Dry Rag in a desert wind dull. Boring, and a drab expanse of dribble supplanting wisdom and enlightenment. Mike Ojo would be rolling his eyes and shaking his head were he to read this.
Its just this simple:
Dunk the Sling part in the first tub. 2 to 3 minutes of fizzing later, it goes from shiny to dull aluminum. Dunk in the rinse tub. Finally, dunk in the M-CR 1201 AERO, and 2 minutes later, the piece has a gorgeous mesmerizing gold color. Don’t pawn it. It’s not worth it. Trust us.
Now for the real details. We had three ways to deal with all the parts, based on how big they were. For the small parts we used mixing tubs. We followed the instructions
on the jugs and mixed the C-IC 33 AERO with 3 jugs of water in a tub, and the M-CR 1201 AERO with 2 jugs of water.
as you guessed, we put water in the third tub.
We found timing the soak in each tub was important. Too short a time, and it wouldn’t get enough treatment, too long, and it would get too much and waste the chemicals. We soaked for 2 minutes in each tub, going a little longer at 2½ minutes with the last several pieces. The parts in the C-IC 33 Aero fizzed away in a stately frothy bubbling, less fun than coke and mentos, but the parts came out nicely etched into dull shine-less bland new style chemistry set gray.
Once rinsed in the water tub, the parts went into the M-CR 1201 AERO and came out beautifully golden, like the fields of waving rapeseed splashing across the Aroostook river valley.
With the small parts through the Midas slog, our attention turned to the spars.
The spar pieces were too long to fit in the tub, and trying to find a larger tub was both expensive in tub and in alodine solution. So, we came up with a wonderful clever Third World scheme of using tanks made from 6=inch PVC pipe. We saw a version on one of the blogs (May have been for an RV-12). That version had the pipe sawn in half lengthwise and capped at both ends to make open troughs. The downside was the floor space it took, and handling the solutions when done could get even more toxically messy.
Fortunately, the CT Slingers Headquarters has high ceilings, so we would go vertical to create new system, the Vertical PVC Pipe Sling Parts Alodining System (in keeping of our pledge to use acronyms, VPPSPAS). Featuring three vertical tubes with drains in the bottom and removable caps which could seal and store the nasty solutions safe and sound.
After a fevered scurry down to Granite Plumbing Supply in Groton, and some febrile redneck engineering, we had our VPPSPAS. As you can see from the photo, we made three tanks out of 6” PVC pipe, with drains at the bottom and caps at the top to make handling of the cancer agents easier. Each drain was made from ½ inch PVC tubing and valves connected to the bottom of the tanks using threaded fittings. We are pleased to say we had no leaks, hopefully we’ll have the same success when we assemble the fuel tanks.
To save space, we to set these up vertically by mounting them to the side of the Sling Parts Drying Rack with a holder we made out of 2x 6’s and plywood braces. You can see in the photo how we put it together.
To keep the whole thing from toppling over from the Howard Taft weight of the fully filled VPPSPAS, we installed an aesthetically pleasing tub of rocks in the bottom of the SPDR. The whole setup looked elegant, real Ghetto Industrial, especially with the brawny red strap accessory holding it all together.
We filled the tubes to about 5 and a half feet high with our solutions, and then proudly started the treatment. We stood on a ladder while lowering each piece into the VPPSPAS with safety wire looped through rivet holes. Sounds really clever except we had to hold them with gorilla hands fattened with the hazmat handling gloves. The wires would sometimes slip out of our sausage fingered grasp, and down it would go. It would take a herculean effort involving a Mutter museum variety of tongs, pliers, and hooks to fish them from the deep cancerous murk.
In the end, we got the spars through to process without getting cancer or our hair falling out. (as of yet), so we can declare a qualified victory, even with doing the circus act on the ladder with all the toxic nasties dripping all over the tubes.
And then the skins. How do we do the skins. We didn’t have a big enough vat to immerse them in. The only solution was to do the brush on technique the way they say in the directions, with the adamant demand to not let the M-CR 1201 AERO dry out during treatment. Right. Don’t let it dry out. Of course, the directions didn’t say why we needed to keep it wet. Whatever the reason, it must be too catastrophic to reveal. all the more reason to keep it wet. Our zeal with the whole “Don’t Let It Dry Out!!!!!” thing led us to believe we needed to keep brushing for 2 minutes, the nominal time for treatment. This rigid interpretation and implementation of the rules yielded less than desirable results.
It al started out innocently enough. Instead of using the diluted solution, we used it straight up, pouring a half gallon into the mixing tub. We stood the skin up on the edged of the tub, and since the skins are designed to fold over the whole frame of the empennage component, we had to spread them apart to deal with the interior and went to work with some cheap brushes that we had on hand. Hopefully, none of this would hang in the Louvre.
We dipped the brushes in the Fizzy C-IC 33 AERO acid prep, and started in with the brushing. it was brush, brush, brush, keep it wet for 2 minutes, brush, brush, brush, brush in earnest, ye lowly swab! Got to keep it wet! Then rinsed and started in with the M-CR 1201 AERO for 2 minutes, keep brushing, keep it wet! the admonishment burned into our brains. And therein was what caused the problem.
All the brushing was preventing the alodine from reacting with the aluminum. The result was an inelegant streaking all over the surface. Like tiger stripes, not on the tiger, but on the idiot who found out whether it hurt to pet a kitty the wrong way. We eventually learned that by backing off on the febrile brushing, and just brushing the solutions on and waited, there was a huge reduction in streaking. We decided to live with all the streaked pieces, perfection is the enemy progress.
Priming 4 hours.
At this point, we had to decide to prime or not to prime. The same could be said for alodine/no alodine; lean of peak/rich of peak; Ford/Chevy; Red Sox/that team from New York. It is a bar room discussion the bartender prays won’t result in a visit from the local constabulary followed by a call to the insurance company.
The hard truth is, 6061 aluminum is already corrosion resistant, but there are arguments for extra protection. In our case, we are doing it because we can, and it is our first time, and being a learning process, we want to learn this Sling building thing really good. Plus, it would give us an excuse to wear the same sexy Tyvek coveralls that Naomi Campbell wears when she indulges in her aviation pursuits.
That opened up the next question. what sort of priming? We read through the blogs, noted that many were using rattle cans. That would be a problem. This project involves teen labor. Give a teen a case of rattle cans and Lord only knows how many fire hydrants, mail boxes and lawn ornaments might get tagged. It’s fastest way to ghettoize the neighborhood.
Another serious concern is the durability of the rattle can stuff. We looked at a few experiments done with the different primers, including rattle cans and 2-part epoxy, and the 2-part epoxy was more durable, and was less likely to flake off. There is no room in aviation for flakes.
Working with the 2-part system wasn’t that bad, we mixed the 2-part epoxy in equal amounts, let sit a half hour and pour into the spray gun. Even with having to clean the spray gun dealing with the 2-part epoxy was easy compared to dealing with the cancerous nasty Alodine solutions.
There is one downside. In terms not good times to be had, cleaning spray guns after every session stops just short of cleaning the fryolator at McDonald’s. So, we made sure we had everything CRM organized to minimize the spray sessions, all the parts in trays, paint ready. We rolled SPDR onto a sheet of polyethylene, and turned it into a ghetto grade paint booth by wrapping 3 sides in Polyethylene, which works well as a popular siding option in Northern Maine (tar paper being a very close second).
When it comes right down to it, spray painting is spray painting, whether tagging or rust proofing. Either way, it goes pretty fast, even if the police aren’t lurking around the corner. We sprayed the small parts first, tray by tray, starting with one in the bottom slot of the SPDR, and adding the trays into the SPDR as we went. After the small parts were done, we pulled out all the trays, hung the spars in the SPDR, and sprayed them. Once those were done, we put them back in the Bags and finally painted the skins as they hung in the SPDR. in short order we had all the frame parts done. We could rejoice that this part of the prep work drudgery was complete and we had parts ready for assembly, all without our neighbors’ houses, mailboxes and cars tagged.
Next: Erector Set Time