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Converting the Monogram AT-37

Converting the Monogram AT-37

 

by Walt Moore

 The Monogram 1/48 scale AT-37, “Dragonfly” is an attack aircraft built on the Cessna T-37 airframe. There are numerous changes made to support the “Dragonfly’s” role as a strike bomber, most notably, the armament and the engines. Instead of a pair of 1,025 lb. thrust Continental T-25 jet engines, the conversion has two GE J85 – GE 17A turbojets, much like the T-38, “Talon”. Those engines transform the “Tweet’ into the payload bearing “Dragonfly”! The kit I purchased is a 1992 printing in current distribution.

The References

Converting the Monogram AT-37There are many publications out on most of the training aircraft used by the US military, but considering the tenure of the T-37, there is very little on the shelves. In order to accurately “retro” the AT version that the kit is based on, I chose some good references, namely, the “Aviation Enthusiast Corner” at the aeroweb.brooklyn.cuny.edu.database/aircraft website, which provided me with appearance specifics for the aircraft I am modeling; the Wright-Patterson AFB website: www.wpafb.af.mil/museum; and my personal copy of USAF Colors and Markings in the 1990s, Dana Bell, Greenhill Books, Presidio Press, 1992, for proper coloration and markings for my model. Help on the instrument panel was obtained from “AviationEnthusiast Corner”, a photo copyrighted by David Best, and from “papertrainer.com”, which offers a beautiful full size laminate of the panel at an economical price.

Building The Model

The kit provides a quality molding in neutral gray polystyrene with raised detail, typical of Monogram’s main product line. The instructions are clearly illustrated, but I deviated in sequence in order to perform the modifications needed to the fuselage and wings; both were individually assembled to make them easier to alter before being attached.

 

The Wing

Converting the Monogram AT-37The wing has to be “cleaned up”. There are four notches stamped into the undersidewing panels to receive the ordinance pylons and a box extending from beneath the left air intake that should be covered on the inside in order to be cut away and puttied over from the outside. Cover the openings with thin plastic sheet scrap, then glue the halves together. The attachment points for the wing pylons flanking the notches should be cut away and the area smoothed flat. First, line the section with some scotch tape in order to confine the area of potential surface distortion. The three notches in each leading edge were filled with plastic strip and sanded to conform to the contour. I used Squadron Green Stuff for the putty; you might otherwise try Testor’s Clear Parts Cement to fill the notches to reduce the amount of surface sanding once the filler dries; this may take longer, but may help preserve more of the surface detail molded on that section of the wing.

Wing and Fuselage

Interestingly, the auxiliary fuel tanks were molded on the kit’s wing tips; this becomes the major part of the wings conversion. Once the wing halves are glued, cut the tip tanks off with a razor saw, lightly sand the exposed edges to square them and glue some solid plastic strips of the appropriate width and cut to length; I used Evergreen (white) .125 x .125 (1/8) strips, two of them, and some Green Stuff to form the needed wingtip curvature for the trainer version. The curvature had to be approximated from the photos, and abbreviated references I have, and also from memory having seen the airplane many times. Once I contoured one tip, I outlined a template to use as a guide for the second tip; a clean piece of cardpaper will suffice.

Finished Wing

Converting the Monogram AT-37The wing tip will approximate an ellipse, bluntly rounded at the leading edge, then tapered back toward a soft curve at the trailing edge. The thickness of the tip is modified by a slight arch from the center at both ends to the top at the crest of the airfoil. The lower half of the tip is “dished” upward to the wing’s chord line.

Again, protect the adjoining outer wing section with scotch tape to minimize surface detail distortion. There will be considerable sanding and shaping to attain a well incorporated wingtip.

The center section of the wing assembly has numerous points for various antennae used on the attack version; these should be cleaned off since the radio systems in the trainer are more simplified. Those antennae will be attached in the last finishing stage. Finally, the last remaining detail on the wing to alter is the aileron trailing edge; these should be filed back to the same line as the flap trailing edge since the trainer does not have the widened version. The wing assembly, once modifications are completed, tape removed, and washed down, may be temporarily set aside.

The Fuselage

The fuselage requires modification to remove the locations of the 7.62 mm mini-gun in the right side of the nose and the site for the radome on the top rear section behind the cockpit. Both locations can be taped off and sanded down easily once the fuselage halves are glued together. Before joining the fuselage halves, I glued the nose wheel well to the front cockpit wall., then the basic flight deck was glued in it’s place inside one of the fuselage halves. I missed reducing the extension on the front right side of the cockpit floor centered on the right seat. The trainer has a side-by-side seating arrangement for student and instructor rather than the additional instrumentation in the bomber. Clip this extension back at the same angle as the protrusion on the front left side floor. I made up for the omission by clipping the extension short in order to hide it behind the instrument panel, more on the panel later.

Once the removal of the radome and the nose gun sites is complete, I filed the glue seam along the fuselage. It should be noted that the sanding and filing process starts with a coarse grade, then a fine grade, then 000 steel wool to smooth out scratches and 0000 steel wool to polish the sanded surface; this enables blemish free surface once the paint is applied. Lastly, the scotch tape is removed, the fuselage was inspected for uniformity of detail and for marring, any imperfections were smoothed out.

The Final Assembly – Interior Detail

Now that the model is ready for final assembly, let’s begin with the interior. I add enough detail to highlight the major areas that come in view with a large cockpit viewable under a raised canopy lid.

First, the seats are assembled and painted along with the cockpit interior. The necessary details here are lap belts and harnesses, which, although they may be obtained from several after market parts makers, I like to fashion them for myself using freezer tape and Swingline S. F. 1 sharp point staples. Common paper staples can be easily shaped into buckles and connectors with the use of a small needle nose pliers and a wire cutter.

I cut a 1/16″ wide strip of freezer tape for the lap belts with a sharp point X-acto knife and folded it over the end buckle formed using part of the afore mentioned staple, these are done and fixed down in the rear of the seat cushions. Next, I add bent staples for the connectors to a second strip and add a end buckle at the end of the strip, which is then adhered to the top rear of both sides of each seat – these are the inertia reels that attach to the lap belt. The seats were then glued in their places on the flight deck.

Opened cockpit closeup

The instrument panel is a standard dual panel with conventional indicators and gauges. The panel was painted neutral gray to match the proper metal interior shade. Since the size of the instruments is so small, I painted the instrument casings black, then, once dry, lightly highlighted the dials with a white gel pen. A final touch was added by putting a drop of Testor’s Clear Parts Cement over the dials to simulate the glass faces; do this with a pointed end of a toothpick.

Converting the Monogram AT-37Now the instrument panel is attached to the cowl glare shield, then set aside until later. My display will show the canopy raised, which invites the eye to inspect the “office’ where the fledgling learns from the master. But next the canopy and windscreen over the cockpit in the down and locked position, then masked the glass portion with a mixture of liquid detergent and Elmer’s White Glue being careful not to let the mask slop over the framework; one light coat, dried, then one heavier coat will cover the clear sections of the canopy. The wings, fuselage and tail were permanently joined. The landing gear doors were tacked temporarily in the closed position by in with some Elmer’s White Glue. The gear doors were later removed for the complete landing gear assembly after the paint job is finished and the decals were applied. Let everything dry and carefully inspect for flaws; catch them while you can, because the next step is the paint job!

The Color Scheme and Markings

The trainer’s color scheme has a gloss insignia white upper surface (FS 17925) and gloss insignia blue underside (FS 15044). These colors were airbrushed on the model using Testor’s flat acrylics, major panel lines were then highlighted with a .005 mechanical lead pencil, and the model was sprayed with Testor’s Gloss Clearcote. Masking for the color separation between top and bottom was accomplished using some friskit paper the line where the colors meet was sharpened by a white gel pen and straight edge. Once the markings were applied and inspected for cleanliness, I oversprayed the entire model with Future floor polish to seal the finish.

Markings for the T – 37 came from the decal scrap box and are mostly remainders from still fresh sheets. The white lettering came from an Aeromaster 1/48 scale lettering sheet. The AETC crest was fashioned by hand on a similar shaped crest, the star and bar, and the “USAF” came from decal sheets from previous ;projects.

The Display

Converting the Monogram AT-37Specifics for the Wing and AFB markings came from the “Aviation Enthusiast Corner” website mentioned earlier.The display stand is custom designed using a 1/4″ plywood base, 1/8″ Masonite (for the ramp), some appropriate molding for the edge frame, and 1/8″ (.093mm) Plexiglas for the cover. The Plexiglas is attached using clear caulk judiciously applied to the adjoining edges.

 

 

About the author: Walt Moore is an independent chartered financial consultant with a financial planning practice located in Slidell, LA. He is an ex USAF staff officer and has been a private pilot with several hundred hours of flying time, a writer, and an airplane modeler since the age of 8. Some of his work is on display at the Louisiana State National Guard Museum at Jackson Barracks in New Orleans. LA, the LA ANG section.

Photos by the author