8 Hours of Shmoozing.
Stuff we used:
Acetone- Cash’s hardware Mystic, Connecticut
Chemseal B2 Tank Sealant Cs3204, (hereinafter referred to as shmoo)- Aircraft Spruce and Specialty
Loctite 577 sealant Loctite Co., Rocky Hill, Connecticut
Popsical sticks, Neighborhood kids and Walmart.
Paint Rags- Rings End Paint, New London, Connecticut (They got the best paint rags in town)
We here and Connecticut Slingers are a busy lot, extracting our meager funding from the Drug Trade takes a lot of effort. So much that we are left with precious little time to savor and enjoy our beloved TSi build, let alone another trip to OSH or the Cannes film festival.
Fascinating place this Cannes film festival, sometimes, amidst all the mayhem, arrests, and dolled up debutantes, they show films. And give prizes.
Rumor has it that as with previous years, The officials quietly phoned the Brilliant Mike Blythe, and humbly asked him to hold back on submitting his latest film, the one in which he is interrogating his attorney concerning his extracurricular activities. The officials were concerned that: A.) it may add yet one more conspiracy theory to the pile, and B.) The artistic brilliance would not be fair to the- shall we say- less clever and uninspiring rubbish the judges would have to sit through.
Fortunately, we can see it on YouTube. The opening shows Mike’s eyes gazing at the Entire Sling Legal Department sitting in front of him, as he opens the interrogation with: “You should be sitting back with slippers and pipe, but here you are, still trying to prove yourself.”
In another scene, the attorney is on a manic and quixotic bike ride alongside the runway as Mike takes off in a nice Sling 2. His legs were pumping along like the pistons on a Corsair’s Double Wasp during a power dive. Was he chasing after Mike, trying to get him to pay his bill? Or, was he simply racing it? did he declare victory since the Sling’s wheels were not touching pavement at the point it reached the end? These questions need answers, wait 35 years for the Sequel.
There is another vignette into the mind of attorney James Esq. The film scene is about the Sling TSI, and it had a bit where James solemnly states that the Sling is a truly modern aircraft. Well, Councilor, that may not be entirely true. We here at Connecticut Slingers have uncovered evidence that it still pays homage to aircraft of yesteryear.
Having a luddite streak in the design is nothing to be ashamed of, just about every airplane has some old tech in it. The pitch trim in many transport category aircraft use screw jacks, a 15th century technology. The Piper Cherokee tips its spinner to the Wright brothers with a piece of bike chain to turn the flap torque tube. And Burt Rutan has his obsession with canards, an unequivocally clear Wright brothers rip-off.
The Sling, we attest, is no different, It wouldn’t be a great airplane unless it had something from the past. After a chance event, we found the Sling’s throwback to some tried and true aviation tech from none other than the Hindenburg. We have proof.
Now, as we wrote this, the High Wing Cruise Crew were merrily crossing the Atlantic in style, having a good time, in spite of all the bureaucracy. It’s a bit ironic that Our Assistant Adjunct Associate Researcher from our Ministry of Truth made his own degrading Atlantic crossing to tend to some drug trade business, and stoically accomplished in decidedly less opulence, the wretched brutal Teutonic austerity of Business Class on a Lufthansa 747. Let’s just say there is more style in a Sling.
Hohenzollern here we come: dritte weltklasse im lufthansa
After a week of toil in an undisclosed drug lab somewhere in Baden-Württemberg, A foray was made south down route 465 then on to 30 to the Zeppelin Museum and Research Center in Friedrichshafen on the Boden See. It was there that we closely examined an exact reconstruction of the LZ-129 Hindenburg passenger section. It was the same scale as the original down to the last silk wall panel, turn buckle and rivet. The complicated framework is astonishing, intricately fitted and riveted together, and coated with its blue coloring. The blue couldn’t be Prussian Blue, this is Baden-Wurttemberg, after all. But it does match the blue on the fuel system fittings, Mike Blythe’s secret homage to the greatest airship there ever was, is now revealed!
Top Photo: Inside the top secret behind the scenes view of the LuftSchiff Hindenburg (LZ-129). Note the Baden-Wurtenburg blue framework color, the exact same color Mike Blyth personally selected for the fuel fittings, as seen in the lower photo.
We dwell on the fittings here because like other Sling tchotchkes, the Hindenburg-Blue fuel fittings were missing. It is striking to think how progress is slowed to such a road-construction pace when such a small part turns up missing.
How worthy it is of lamentation! if it were the fuel feed or return fitting, we could tape over its hole, pressure test, and install on the wing. We would then close out with installing the fittings through the fuel sender hole afterwards, but not so with the overflow fittings!
At times like this, George Herbert’s famous missing nail poem from his Outlandish Proverbs book is in order:
“For want of a nail, the horse’s shoe was lost.
For want of a shoe, the horse was lost.
For want of a horse, the rider was lost.
For want of a rider, the battle was lost.
And for want of a battle, the kingdom was lost.”
Here is the Connecticut Slinger’s version:
For want of a fitting, the bulkhead was lost.
For want of a bulkhead, the tank was lost.
For want of a tank, the wing was lost.
For want of a wing, the plane was lost.
And for want of a plane, Oshkosh was lost.
We should ordain George Herbert an Honorary Slinger, all be it posthumously.
There wasn’t much we could do about the missing tubes, so we kept buildin’.
First, we did the paperwork part. we filled out the missing parts order form and waited. And waited. Suddenly, we got a linked in message from brother Metodi Filipov who was making a pilgrimage to Tedder Field to build his unit. He must have wasted some of his time reading our blog, suffering through a few lines, and concluded that those poor droogs need help and not just in the writing department. Whatever his inspiration, He took pity and was kind enough to ask whether he could bring anything back. Funny he should ask.
Until Metodi brought back our overflow tubes, we busied ourselves with getting the left fuel tank as far along as we could. We started with getting the skin ready, such work that it was. We decided not to use the green epoxy coating on the tank interior since it might flake off and clog the filter. That said, we were having such a fun time watching the fizzy fizzy while allodining the small parts that the tank ribs, got allodined along with all the other wing parts. Aw well. As for the skin, it was too big for us to allodine, and so it escaped the fizzy fizzy make over.
We did have a small problem which we found during our mulling about waiting for some inspiration to accomplish something. We were test fitting the fuel filler in its designated hole in the skin, and low and behold, the filler ring part the cap fits into was too big for the hole, by about 1/8th of an inch. Ugh! One more thing.
Our Minister of Procedures and Techniques sent another febrile late-night text to Mssr. D’Assonville asking what a good solution would be.
Thank God he is in California, and we are on the east coast.
His responded with “Make the hole bigger.”
We wish we here at Connecticut Slingers had half his wisdom.
“How shall we make it bigger Oh Great One?”
“Use files and do it carefully” Jean patiently replied.
And then, after rummaging in the murky depths of our Box of Eventually Useful Stuff (BEUS), we found a hole saw. We had several, and we checked the diameters of a few, and found the 23/8th inch one had the same OD as the ridge on the fuel filler neck, which sat flush with the skin when inserted into the hole. Awesome! We were saved the hours of tedious toil that we won’t have to subtract from our YouTube time. Now all we needed was to figure out a way to keep the saw centered over the hole while we cut away the excess sheet.
15 minutes of thought and pondering later we created the Sling Fuel Filler Hole Centering Jig (SFFHCJ). A work of pure artistic genius. We used our drill press fitted with the hole saw to cut a disk that would just fit in the hole for the filler cap. Next, We screwed that to a carefully hand selected piece of scrap plywood. After a bit of sanding, it fit nice and snug in the fuel filler hole, its beautiful rustic wood grain was accentuated with the dark patina of a couple of drywall screws, a true work of art.
It was all downhill from there. We stuck the disk part of the SFFHCJ through the hole and sawed away with the hole saw. and in short order the excess aluminum sheet was symmetrically trimmed away leaving a nicely centered hole for the filler neck. We returned the hole saw to the BEUS, and marveled at the uncanniness of just how well it worked.
Left: using the Drill press to cut a disk. the middle the disk fits. Right:The disk has been screwed to a plywood board and now is guiding the cutting of a wider hole for the fule filler neck, perfectly centered.
The next tricky bit was forming the fuel sensor rod to the right 67◦ angle as it was shown in the Sling Legos instruction manual. The manual has a picture of how it is supposed to look. The bend is supposed to begin 98mm from one end, and 122.82mm from the center of the flat part of the plastic float, which can be found if you gaze intently at the mold lines on it. Sounds easy enough, with a caliper and a microscope. But the radius of the bend is small, and the rod is pretty stiff. We would also have to trim the rod to the right length.
How to bend the float rod.
One way to do it is to put marks at the 98mm and 122.82mm points, and then bend in a vise. This may be okay to start, but you might not be able to get the angle sharp enough, making it a bit rounded. Plus, we would have to get the genuine Harbor Fright vise out of its box and bolt it to the SBB. That is too much effort. We have another idea, and it would be much more fun.
For those of you hoping to play with a blowtorch during your sling build, this is your chance! Hee Hee Hee!!
We started with drawing 67◦ a reference angle on a piece of pine which is the angle shown for the rod holding the float. We would compare the bend to that. Next, we made a mark on the float rod at the 122.82mm point where the start of the bend would be. Good luck with accurately marking the that .82mm bit.
After that, we were ready to bend metal. We muckled a good tight grip on the rod with a pair of vice grips near the122.82mm mark for what came next. We didn’t hold back as we blasted it to a nice glowing red with a MAPP gas blowtorch. While it was hot, we used another pair of pliers to bend the rod close to the target 67◦. We checked it against the mark on the pine, and after a few more excuses to use the torch, got the bend to crisply match the 67◦ layout with a nice pointy apex. After it cooled, we used a dremel tool to cut off the free end leaving 98mm from the bend point to match the required length. it was ready to go back on the sensor assembly, ending the blowtorch fun. Drat.
Using a file to mark the bend point at 98mm from the straight end, and128.82mm from the middle of the plastic float.
The fuel sender is part of rib 2 (WG-RIB-S22-R-F-0) which also has a couple of Hindenburg blue fuel fittings (HW-FTG-310-X-X-0), used for the the feed and return. Rib 3 (WG-RIB-203-R-F-0) also had a Hindenburg Blue fitting ((HW-FTG-309-X-X-0) used for the fuel overflow assembly. All of which needed to be treated with the Loctite 577 thread sealant. We like to support our local businesses and used it, also Mike Blyth insisted on it. We assembled Rib 2 and Rib 3 complete with fittings and sender, but would do the sealing with shmoo at the same time as riveting the frame together so as to use the same tube of shmoo.
Heating and bending the rod using a MAPP gas blowtorch. KEWEL.
Having the tchotchkes delt with, we moved on to the test assembly to make sure everything fit and could align with the wing. To start with, we clecoed the ribs on to the smaller front channel (Channel 7, P/N WG-CHL-016-R-F-0). It’s a bit confusing, so to make it simpler, we’ll call them “nose” and “baffle” ribs and leave it to you, dear reader to guess which is which. Sorting which rib went along the channel was a little tricky, since we were too lazy to tag and label the lot before after their Alodine spa treatment. We did have a couple of tricks to help to get the rib arranging correct. The first was to go by size. We stacked them like one of those Russian matryoshka dolls to get some order to them. Then we prepositioned them along the channel based on size, biggest rib near the wing root (the part that sticks into the fuselage) and the smallest towards the wingtip. Mike Blythe helped out with notches on the flanges like he did with the trailing edge ribs (P/N’s WG-RIB-301-R-F-1 to WG-RIB-301-R-F-1). He had notches put near the top on the outboard most rib, and one near the bottom for the inboard rib, except the one closest to the fuselage which doesn’t have a notch. You can see the notches on both the nose ribs and the baffle ribs, they match up notch for notch.
Checking the bend angle on the angle drawn on a piece of pine.
Cutting off the excess rod. the straight end of the rod is supposed to be 45mm from the bend.
Arranging the ribs. Big ones go on the inboard end, small ones closer to the wing tip. The smaller nose pieces have notches in them which help orient them to the front, wish they told us that in the Legos instructions, but if you use a magnifying glass, you might be able to see the notches in the nose pieces.
This brings us to the hardest part, test covering the frame with the skin. It is a tight fit and the nose ribs would bend making them hard to line up with the rivet holes in the skin. We ended up using a trick using an awl in the rivet holes to align the nose rib with the skin before clecoing the two together. Once everything was aligned, we found it surprisingly adorable just how well the rivet holes matched up. The last piece, the big Fuel Tank Channel 15 (P/N WG-CHL-008-L-F-1) labled 26 in the above drawing from the legos book popped in easily. That put us on a roll. It was utterly shocking (in the nicest way) when we test fitted it on the wing. That was a nonevent, it fit just fine. One could almost argue this wing mating step isn’t necessary. SlingTsiBuilder had the Slingers at Midwest do the tank assembly, so he didn’t have Shmoo oozing all over the place and sticking on everything. From what we have heard, the tanks fit on his wings very well. Indeed, our tanks had no problem with the test fit, the holes on the edges of the skins aligning nicely with the holes on the spar.
Ribs clecoed, the puke green blends nicely with the silvery aluminum. the flat part of the channel goes against the internal “Baffle” ribs, and the rivets will go through from the side with the small “Nose” ribs. (Mixed Media, 2022.)
This left us with just the final riveting and sealing to do. A daunting task. Like the final leg of scaling Everest, not the same level of course, but parallel. We will point out here that the rivets for the wetted parts of the tank have a different design and use a different mandrel to make a sealed rivet. These rivets have the same domed or counter sunk head as the normal rivets, but the part that sticks in the hole covers the head of the mandrel, which is made with a different steel than the regular rivets[ja1] . The idea is to be completely sealed, a nice to have with the fuel tank.
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The other half of this is the shmoo. Since this is spawned from vulcanization, and Charles Goodyear is from Connecticut, we are going to do some blathering on about it.
The left rivet is for the parts touching fuel tank, the right one is for everywhere else it fits
Shmoo is the nasty icky sticky garbage dump smelly goo we used to seal tanks with. A common brand name is Pro Seal, but there are others just as nasty. We used Chemseal B2 3½ oz tubes. It comes in 2 parts, a white goo and a black muck. When the white goo is mixed with the black muck, it makes a dark gray sticky gunk with the consistency of silicone caulking that sticks to everything it touches. Its worse than Covid sticks to a conspiracy conventioneer. It smells like a skunk that uses a triple distilled version of its own smelly squirty stuff to shower with. The downside is it is sticky. Really sticky. If you stick your hand into the tank and brush up against it, it will stick to your left little toe. It just will. Even if you look at it, it will stick somewhere on you. Especially your gloves, since your fingers are down in the works It gets all over your gloves, making them sticky, so when you grab a rivet to load into the rivet gun, it will stick to your gun, the thing you set the gun on when bungling around with the cleco pliers, the cleco pliers, where you put the cleco pliers when you set those down, and your mailbox at the end of your drive way. It is sticky, icky smelly, gooey and oh, by the way did we mention it is sticky and smells? Now, the smell isn’t too horrific, but couldn’t they mix in a little bit of lavender? It just makes you wonder what the hell is this stuff.
Science class time.
The shmoo sticks to everything, you can’t see it, but it is also sticking to my shoes.
Here is an excerpt from a science magazine:
“The commercial vulcanization process of liquid poly-sulfide (LPS) or polysulfide oligomers are based onthe oxidation of ASH groups with dioxides of a transition metal like MnO2 PbO2 ,or Na2Cr2O7. In this process, the oxidation of mercaptan end groups and branches leads to the formation of disulfide cross-links
Blah Blah Blah
The shmoo is mostly a gooey white gloop that contains a carbon compound, which puts it in the same class as plastics. What makes it special, in its own icky sticky smelly way, are Sulfur atoms chemically bonded to a few carbon atoms and hydrogen groupies making them what they call “Poly Sulfides”. While lurking in its container, This gooey mass of Poly-Sulfide molecules don’t do much except smell odiously like the devil’s arm pit. However, when its mixed with the black gunk that comes in a separate container with it, things start to happen.
The black gunk contains manganese dioxide and carbon black. The manganese dioxide reacts with the hydrogen groupies causing the oxygen atoms from the Manganese dioxide to run off with them to form water happily ever after. This leaves the sulfur atoms on two different molecules with nothing to do but chemically stick to one another, binding the two carbon compound molecules together forming what scientists called a crosslinked elastomer or, “rubber” by everyone else in the universe. The Black gunk also contains carbon black, which in addition to making the shmoo black, makes the new rubber seal stronger, giving it a good ability to stick together when one pulls on it. Finally, the shmoo also includes ingredients known as accelerates. Depending on how much of these are in the mix, the reaction can take hours turning the shmoo into a floppy rubbery mass that sticks to whatever it was being sticky with. For us, we hope it is the gaps between the ribs and skin of the fuel tank, and nothing else. good luck.
Here is an example of what we are talking about. The photo does a better job showing it than this monotonous drivel can by explaining it.
A type of disulfide going through the cross linking where to sulfur atoms bind together turning the shmoo into a rubbery seal. The top part is two molecules of shmoo and the [O] comes from Mangenese dioxide, which is found in the (MNO2) in the black gunk. The other bits are in the white goo. The two -SH that you see at the top will work with the [O] to stick to each other and form the solid de-stickified shmoo. Of course, it will still stick to the metal and provide a seal.
As you do your shmoo shopping, you will notice there are a few different types, based on time it takes to cure among other things. The different times are due to additional chemicals in the shmoo that will speed up or slow down the rate the shmoo does its thing after the black muck is mixed in. We got the CS 3204 B2 version, which takes 24 hours to dry, but it gives us 2 hours to work with it, a blessing considering our gorilla finger dexterity.
Aside from it sticking to everything coming within about 134,675,347 miles of it, working with the shmoo isn’t that bad we just needed to deal with it defensively. We kept a few useful things ready: a tub of acetone to clean off dribbles and drips from where they shouldn’t be, some rags, popsicle sticks and a gargantuan elephantine Starship One mountain of gloves. We also had a plan. We made sure everything was in easy reach and thought about how to do it quickly before the shmoo hardened in 2 hours.
Though the shmoo is available in paint cans that come with the black muck in cute little tubs, we used the small caulking tubes with the black muck in thin tubes sticking out of where the shmoo is supposed to squirt out. We liked this style since it was dispensed with something with a trigger. Evan Brunye used this caulking tube style and talks about it in one cinematically cutting edge video. he shows us his marvelous and clever 3D printed adaptor system, which also includes the best use of PVC pipe since the toilet drain. We don’t have a 3D printer, so opted to buy the dispenser.
Instant Shmoo. Mix, then lock and load.
We started the final shmooing and riveting by disassembling the tank, since we had to shmoo the joint between the nose ribs and the smaller channel. We kept the pieces organized and paired in their positions along the small channel so we wouldn’t spend cure time hunting for them. While the “B2” version of the shmoo can be worked with for a couple of hours it does take a little more squeeze strength on the trigger after an hour to get the right amount of shmoo out of the tube. Keeping the the ribs organized made it short work applying the bead, smoothing it over the flange area of the ribs and channel with popsicle sticks and clecoing the pieces in place. Next, we riveted the whole thing together with the blind 4.0 X 10 domed sealed rivets (P/N HW-RIV-353-X-X-0) while listening to the Green Dot.
After an overnight cure we started in with the skin. There isn’t much to comment on here, we just applied a bead of shmoo on the ribs and channel, lined the holes up, clecoed and then riveted using 3.2 X 8mm Alu Sealed Countersunk Rivets (P/N AVD 3208 ASK) while watching YouTube.
The last bit of this part was a nice schluvoping of the shmoo over all the internal joints and rivets, giving them a nice gray coating, which lends a level of spontaneity as it accents the native aluminum in keeping with the gray metallic theme. And oh yeah, it also adds some peace of mind against leaks.
the shmoo adds a nice compliment to the metallic monochromatic gray of the 6025 aluminum. Combining the rigid mathematical elements of geometric lines along the seams and the organic amassment around regularly spaced rivets creates a delightful mix which expresses the duality of aviation. It also helps keep the fuel in the tank.
Our overflow tubes still hadn’t arrived when the shmoo sealing the skin had cured itself. This is a bit of a good thing, as we concocted a cunning scheme to water test the tank before we put the second Channel 15 (WG-CHL-015-R-F-1) on. With the tank in our tank holder, we filled it as full as we could and left it overnight inside to keep the deer that hang around our sling build headquarters (SBH) from using it as a watering trough.
The next morning, we checked it and found no leaks. Encouraging. We let it set a couple days, no leaks, then pumped the water out, all we needed was the overflow tubes. Oh, how we wished they were here.
Eventually, Metodi was able to come back with the overflow tubes (Thank You Metodi!!!) so we could do the close out with the large channel 15, which was a bit anticlimactic. The first part was installing the support angles (WG-ANG-02X-L-F-0) on to the channel, applying a layer of shmoo between the angle and the channel and securing with 3.2 x 8mm Alu Sealed Dome Head Rivets (P/N HW-RIV-342-X-X-0). Once the angles were in place, we flipped the channel over and Schlocked a nice healthy heaping gobbing coating of shmoo over the ends of the rivets. From there, We coated the edge of the channel with a generous bead of shmoo and the ribs flanges coming in contact with the channel, and riveted the channel in place. Finally, we squeezed and squegeed a nice bead in the external joint of Chanel 15 and the skin. The one tricky part here is with a corner rivet on ribs 1 and 2 which are at the ends of the tank. The end up being tight against the skin, and it is trick to get them in place, but once they were in the hard part was over. We laid some shmoo over the seam between the big chanel and the skin, since there was no way the shmoo over the interior areas where the rivets poked through. We filleted it with a popsicle stick, and declared fait au complit.
Water testing the tank.
We waited a week, during which we tried to fit the fuel tank in place on the wing, and it did not quite fit as easily as when it was just clecoed. We got the brilliant idea that there was just a bit too much sealant on the seam between the channel and skin, so we cut some back. This was a mistake.
1setting the fuel tank support angles in place.
We had some specialized equipment for testing pressure, which includes a calibrated pressure gauge that we were feeling so clever about. Well, we tried to pressurize the tank to 1 pound, and heard the tell-tale hissing with no pressure build up. ugh. We traced it to holes in two of the corners where the rear channel rests against rib 2. The holes were within reach of the filler cap, and so we could smodgel some of the shmoo over the holes from the inside using swab stuck on strategically bent heavy wire, and we added some on the outside. Another week and we tested again. We pumped the tank up to a pound, and saw some pressure, but it hissed away into thin air. We started drizzling some propylene glycol solution over places we thought would be likely culprits and found the food additive bubbling out of to a length of seam we cut away where channel 15 and skin meet. We would wait until we were sealing the right tank to fix this one, it would be stupid sacrifice a whole tube of shmoo to fix this one leak.
The Tank is foaming at its mouth. Worse than rabies.
We set the left tank aside and went to work on the right tank. The experience gained with the left tank translated into a quicker job of the right tank. We sailed through it, rolling along with getting the frame and skin all clecoed together. The test fitting was just as smooth as the left tank. The right tank fitted snugly onto its spot on the wing. It was as beautiful a frollic as dancing in a nice, sweet-smelling alpine valley meadow in the spring time, full of wildflowers with butterflies flitting about and singing birds swooping and twirling gracefully through the sweet air. Overhead can be heard the sweet drone of a TSI on its way from Topfarm England to Tedderfield. Yes, dear reader, the progress of the right tank went along in such a wonderfully smooth manner, full of leisurely spells of casual fitting and clecoing pieces together, our skill with the shmoo came into its own, and everything was a nice happy Smurf valley. Right up until we ran out of rivets.
Fortunately, the fun thing in Sling building is that there is always something to do, such as the rest of the rest of the right fuel tank, fixing a leak in the left tank, the right wing the flaps, the wingtips…. We will keep working,
Stay tuned.