AZ Models 1/72 Stinson OY-2 Sentinel

Model airplaning lost its appeal about 3 years ago when all building time and energies were diverted into the decree of  a stately pleasure dome where Alf the sacred river ran.  Actually, it was the Potomac, right where it empties into the Chesapeake Bay.  Those bodies and the Rappahannock cordon off a spit of land known as Virginia’s Northern Neck.  Noneck for short; which coincidentally describes the prevailing physiognomy.   Neither was it  all that stately, which is why so much time and energy were required. Under the last owners’ not-so-benign neglect the house and land had succumbed to the Third Law of Thermodynamics. What limited maintenance had been performed was done by the Billy Bob Budweiser Home Improvement Co. (“Hey, Vern, pass me up anther roll of that ‘lectrical tape.  That ought to stop them wires from sparking…”)

 So after a day of stringing new cable through a cramped oven-like attic; and pipes under a crawl space inhabited by spiders and varmints rivaling anything you Australian fellows cultivate in your Outback, there wasn’t much capacity left for sticking together little bits of plastic; not that there was any place to do so anyway.

 Back at the Mother Ship, this kit lay dormant in the Secret Model Airplane Building Room, but during return visits it inspired no passion.  Checking in on this website, and following the trickle of new releases still provided some diversion; but with so much else needing to be done, building models seemed like a silly way to spend one’s time. Eventually, however, the global accumulation of greenhouse gasses conspired to cause a bit of winter cold enough to call a halt to all house-building; and with little other occupation besides snacking and sampling the Dewars bottle,  I forced myself to finish the project.

Oh – I’m sorry. You wanted a history of the airplane.  Well, there’s little of that to speak of.  The Sentinel started life as the civilian Voyager and was one of those off-the-shelf planes scarfed up by the military at the start of WWII.  It is generally regarded as the most widely used “L-Bird” and served in just about every theater in just about every capacity; as a liaison transport, artillery spotter, ambulance, and general hack, sometimes flying off ships by dangling from a launching cable.  The Smithsonian’s Udvar Hazy annex displays an L-5 equipped with this gear.  It went on to soldier in Korea, assorted “minor” wars, and by some accounts in Viet Nam. Two forms were produced.  The A model, or observer variant, had a wrap-around greenhouse, while the B had a raised fuselage deck that allowed more to be carried but restricted rearward visibility.  Some of those had a long door installed to admit a stretcher.  Mssrs. GOOGLE, YAHOO, and Wiki can tell you more, but if you’re one of us old-timers who prefers to the glow of an LCD screen the feel between thumb and forefinger of a real printed paper page, hunt up a copy of “Box Seat Over Hell” by H. G. Cannon, who restored, as well as wrote about this breed.

After being replaced by the L-19 / O-1 Bird Dog the Stinson  made its way back into civilian hands.  There’s a passel of them still flown by individuals or squadrons such as the Commemorative Air Force (“Confederate” before that word somehow became politically faux-pas) as a cheap warbird, though we all know that nothing which flies is cheap

 A previous kit review confessed a certain Jones for utility, liaison, and training planes.  It’s an affliction apparently wide-spread enough for the minor league kitters to crank out a barn-ful.   In The One True Scale of 1/72 there are several renditions of the Cub, 2 Beech Staggerwings and 2 Be-18’s (3 if you count the AT-11 Kansan version) an L-1  Reliant,  Fairchild U-somethingorother, Lockheed Vega, Norseman, Beaver, Otter, Electra, Cessna Bamboo Bomber, and a prior L-5 Sentinel from the probably now-defunct Beechnut company.  Moving into the more modern age one can chose from 2 Bird Dogs, 2 Skymasters, and even a C172 Mescalelro.  That’s just in injected styrene.  Throw in resin and vac and you can spend an entire modeling lifetime without ever having to stoop to another of those boring old Meezeschmidt 109’s.

A while back I built the  Beechnut Sentinel, but it was a crude affair demanding extensive surgery, particularly vacuforming a new canopy. Sword, which I believe to be a division of MPM or Pavla (as far as I know, Sword is an entity unto itself. Ed), issued a kit advertised as buildable into the low or high backed version, but it was said also to be a disappointment, again in the transparency department. With a growing stash (what stash doesn’t?) I dilly-dallied, till  by the time the decision was made  “Sure -  why not?” the short run had sold out. When A Z Models released this kit I changed my tune to “Buy it while you can; figure out what to do with it later”.

Last-Into the stash seems to have a funny way of muscling its way up to the First-Out slot. It appeared to be a simple, straightforward kit that would take a week or so.  Whooda thunked it would take 3 ½ years.  “Typical East European Short Run” should adequately describe the molding quality. Flash and sink holes appear  to be a thing of the past, but mold seam lines, slight mismatches, troublesome sprue gates, and overly thick airfoils will remain with us until the Czechs and Russians catch up with the Japanese.  This being a tube and fabric airplane, there was little surface detail to worry about, but the door and cowl panel lines were acceptably scribed, and the wing tanks were adequately embossed.   Inter-rib scalloping may be overdone, but in  this scale the name of the game is representation rather than precise reproduction so too much is preferable to not enough. There are no  pins, tabs, or slots, but locations are scribed on the wing undersides for attaching the struts.

The overall shape looked OK with 2 noticeable errors.  The nose cowl lacks the distinctive “flared nostrils” look of the engine air inlets; and the vertical fin is not molded with the fuselage so its  base doesn’t flare smoothly into the turtleback.  Both  problems, if you call them that, can be fixed with fillers and files, but I didn’t. 

The AZ kit includes all parts necessary to construct either variant; almost all parts, that is.  The only thing missing is decals for the A plane.  The parts diagram on the instructions shows 2 decal sheets but only  1 is included.  Speaking of instructions, these are rather poor.  Not that the average  plasticator  under the influence of glue fumes couldn’t figure out where things go, but the diagrams are unclear about which parts go with which plane. There are 2 canopies, 2 fuselages, and 2 sets of gear legs.  One drawing shows the pitot tube affixed to the left wing, another to the right, and a third skirts the issue by sticking one to each wing panel.  Left is right, right is wrong; is that perfectly clear?

Since I already had an observer variant, I decided to build the high back version, to be dressed in the classy dark gloss blue of the Marine Corps plane; but not the eye-piercing royal cobalt blue shown on the box art and painting guide. Before sticking on the nose bowl I drilled out the inlets and glued in a pair of cylinders cut from a radial engine.  I also opened up the air exhaust slot under the cowl.  The Sentinel’s interior is a jungle-jim of  tubes and struts.  Surprisingly, these are provided  on the sprues, but cleaning them up is a chore.  Attaching them to the cockpit tub, as shown on the instructions, requires that the greenhouse be attached in two halves – not the best way to get a good fit.  A better way is to join the transparency halves, then insert the bracing birdcage with canopy-safe glue. Gluing together clear parts without causing blemishes is dicey.   My preferred method is with very sparing application of tube glue.  The bond is strong, there’s not enough solvent to cause fogging and there’s no worry of liquid cement drips or crazy glue crazing.

The fit of the canopy to the fuselage is poor.  Because of the glass thickness the windshield base must be carefully sculpted, and a mating trough must be carved where it meets the instrument cowling ; but  the windshield still does not extend down far enough at its center so a gap is left in the most obvious area.  Trying to sand down and lower the canopy causes a noticeably improper  profile and  step where the rear of the canopy meets the fuselage.  The gap should be left and closed with  some sort of clear filler.   That booger-up then has to be disguised by painting the windshield frame higher than it should be; and the cure for that ensuing fix-it is to simply not look at it too closely.

By the time I had figured all this out the canopy and fuselage had been carved into a complete mess, It was becoming evident  that plastic modeling is a silly way to spend one’s time,  and the project was headed for under-foot euthanasia. BUT WAIT!  This kit offers a second chance with a whole ‘nuther fuselage and canopy. However, there’s only one vertical stabilizer and nose bowl, which had already been glued on.  Cutting away and transplanting  the fin was easy, but removing the front piece would ruin it.  Much easier to simply cut away and replace the entire engine section; which is what I did.

            Being now forewarned of all the foibles, I was more careful on the second go-around.  Besides, the A variant fuselage and canopy fit together slightly better than the B, though the nasty windshield gap still remained. Rather than re-use the interior bracing parts, I made new ones out of stretched sprue, which looked and fit better.  With the fuselage, canopy, and tail section back together it was time to be off to the paint shop; but first the transparency had to be masked using DIY Baremetal foil. That’s household  Renlolds Wrap, smoothed and thinned down by  burnishing with a soft cloth and coated with Superscale metal foil adhesive.  That’s the point at which the model was left languishing  in the Secret Model Airplane Building Room while I went off to do real work.

            We resume our story 3 ½ years later. Since the project had of necessity reverted back to a build of the observer variant, the only color option was olive drab over neutral gray. I like my models shiny, which seems to annoy some folks but that adds to the enjoyment of the hobby.  OD isn’t available in gloss but its easily concocted from Testors little square bottles of green and orange (any of you old timers out there remember when those bottles sold for ten cents – and that was half a week’s allowance?) OD came in an infinite range of  hues depending on who made it, mixed it, schpritzed it, and how long it sat in the sun. It also changes dramatically under different lighting conditions. I mixed this shade to match a color chip in back of one of those Monogram color and marking books and it seems to agree with on-line photos.

            Absence did not make the heart grow fonder for this build, but it did make the foil adhesive grow fonder for its plastic substrate. Removing the mask left lots of gloppy stuff on the formerly pristine window panes.  Surgical swabbing with Microbrushes dipped in pine oil eventually cleaned the mess but the Future overcoat had to be re-done.  Hint #1:  Masking media is more easily and cleanly removed by first GENTLY warming with a hair dryer. Hint #2:  Don’t GENTLY warm too much.  I’m sure you can all figure out how I reached the latter conclusion.

            Since no decals were included for the A variant, markings had to come from the spares box.  I needed a simple scheme; no fancy-schmancy invasion stripes, no nose art, no fuselage or tail codes.  Lo and behold, right on the first page of the op-cited Box Seat book was a shot of an L-5 wearing only pre-war insignia (ball-in-star-in-ball).  I had tucked away several sheets of those roundels in various sizes.  The “Old Glory” rudder stripes might pose a challenge; but lo again and behold again, right on the top of the spares box were not one but two sets that with a tad of trimming and a dollop of fill-in with red and white paint fit perfectly. Things were going too smoothly. The styrene gremlins had to be cooking up something.

            After making everything even shinier with another few coats of Future, it was into the final stretch by attaching the wing panels.  Clear epoxy seemed the safest choice.  I had a tube of Gorilla Glue 5-Minute stuff that was part of a consolation collection of glues that the company had sent in reply to a complaint about one of their other adhesives: “Strongest Wood Glue On Earth” that turned out to be plain old Elmer’s white stuff.  I should have known better than to trust to a suspect product a project as precious as a model airplane.  The fuselage and wings were lined up in a jig cut from a Styrofoam block. The proper proportions of Parts A and B were stirred for the prescribed period. The room temperature was warmed to the optimum level. A thin bead was applied to each of the wing roots and the excess epoxy was left in a test glob to indicate when it was safe to resume construction.

            Five minutes later it hadn’t even thought of thickening.  I checked the label.  Yup, right there in big bold neon letters it screamed: “SETS IN 5 MINUTES!”. But  the fine print said “Leave undisturbed for 90 minutes.” An hour and a half later the test glob was just starting to form a skin.  By morning it was the consistency of Jello. Warm Jello. When I returned in the evening it was still soft and tacky. Gorillas must be the most patient model builders on the planet, but their glue was making me go ape and I decided to stop monkeying around.

            I pulled the wings off (didn’t take much pulling), scraped the glop off the mating surfaces and went back to my old standard tube glue. By the next morning the join was firm enough to continue, but despite the use of a jig, some of the dihedral had sagged out. The kit supplied wing struts are a bit difficult to clean up so I made new ones from Evergreen rods that were scraped and sanded down into an airfoil shape. Plastruct used to make such extrusions in several sizes but the LHS had never even heard of that company.  The kit supplied fixed pitch prop could also use a bit of scraping and sanding to make it more convincing but by the time I reached that part I just wanted to get the damned thing off the bench and onto a shelf so I could go back to doing some real construction. All the other fiddly bits got stuck on and an antenna wire of monofilament thread brought the proceedings to a close.

 CONCLUSION #1:  While traipsing through the Hyperscale site I blundered onto a  build review of the Sword Sentinel kit.  Turns out the AZ is just a re-boxing of that mold, so I didn’t miss anything.

CONCLUSION #2: Playing with plastic  really is a silly way for a grown man to spend his time, but I will have to wrangle a Secret Model Airplane Building Room into the new house.

 Joel Hamm

 April 2012

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