Eagles Talon 1/48 Lockheed GDT-21B Kit Build Review

By Kelly Jamison

Build Review

I always say that I do not write histories on common aircraft. Chances are you have some knowledge on Spitfires, Mustangs, Messerschmitts and Focke-Wulfs or you wouldn’t be here. But a Lockheed GTD-21B Tagboard? Now that is something you don’t see very often. This fits the bill for some history.

The SR-71’s genesis came from a joint CIA/Air Force development program. The A-12 was the original idea that first took flight in 1962. The design morphed into a single seat interceptor designated the YF-12A, only three were built. The SR-71 was developed out of this batch of three.

Knowing the limitations of the U-2 and the fear of one being shot down eventually (Gary Powers proved this to be the case in 1960.) Lockheed started to design a drone that exploited design elements learned on the development of the A-12. The D-21 “Tagboard” was spawned from the fertile minds of the Burbank based Lockheed Skunk Works. First tested on a QB-47 to mitigate risk to any pilots and later from B-52’s to eventually to an A-12 modified with a center launch pylon on the spine of the aircraft between the rudders. This combination was designated an M-21.

There were six successful launches in this configuration, but tragedy struck on the seventh mission which resulted in the loss of both vehicles off the coast of California. Even though the pilot and Launch Control Officer survived the destruction of the M-21, the LCO drowned before he could be rescued. The famous Clarence “Kelly” Johnson cancelled the M/D-21 program and the rest of the Tagboards were designated D-21B’s and were launched from B-52’s.

The D-21 used a Jettison/Recovery method which would have the drone jettison its camera’s content, which would parachute down to be recovered in mid-air by a modified C-130 Hercules aircraft. One drone was lost over mainland China and its remains can still be seen at the Chinese Aviation Museum in Beijing. On a side note, one of the two M/D-21 combos can be seen at the Museum of Flight in Seattle, Washington in all its glory.

I will start by saying that I was not going to do this as an article but changed my mind after I had already started. Hence, no photos at the beginning of the build. This is a vacuum formed kit that comes with the launch pylon for the M-21 mothership. And the external tanks and rocket used for the B-52 launched version. I found the kit to be well formed with nice panel lines. The vent grills are molded in place. You also get external tanks for the rocket version used on B-52s along with the nose/tail cones used on some D-21s. It is done in a white plastic which showed a lot of dust contamination on the surface when primed and sanded smooth during construction. You can make a trailer from scraps and Evergreen sprue by use of the drawings included on the instruction sheet and photo reference if you wish. I used an old Testors U-2 trailer I modified. It is not totally accurate, but it looks the part.

I took a magic marker and traced the outer edges of all the parts on the vacformed sheets to help me see where to cut easier. I used scissors for this. Others use a scribe to thin the plastic edges, then “pop” the parts out. I noticed the actual aircraft is concaved in its shape, so you think the bottom section is warped but it fits to the anhedral of the top piece very well. I used double sided tape to stick a sheet of sandpaper to a piece of glass so I could get a totally flat surface to sand the edges smooth. This proved to be a problem because of the heavy anhedral the aircraft has. So, I moved the glass to the edge of my desk and just worked on half at a time to get the top and bottom halves flat enough to mate together. I took this time to spray a coat of primer on it and sand it down to see all the flaws on the outer surfaces. There were ripples and lots of debris marks and bubbles that got filled in.

I cut out the intake cooling grills on the top of the fuselage to try to improve the look a bit. It was a mistake. The D-21 has a grid for the intakes that is very difficult to replicate. I tried with plastic strips but could not get a good look out of it so I superglued fine mesh to the inside of the fuselage by taping it into place then supergluing it to the inside but still couldn’t get that grid look I wanted. I then custom cut out mesh to match each of the intake areas and used thin superglue to get it fixed into place on the outside effectively doubling the mesh to take up the depth. Had I just taken the time and thinned out the plastic around the vents more, I could have saved myself a lot of trouble. This looked a lot better but still wasn’t like the real deal. I was never satisfied with this solution. Live and learn. (Famous last words of Leonidas at the Battle of Thermopylae.)

Like most vac kits, lots of imagination and scratch building is needed. I replaced the intake area with brass tube and did the same for the exhaust. It took a bit of building up and sanding that front area of the intake. The aerospike goes in after painting so don’t worry about it for a while. I put an old scrap engine afterburner from the ancient Monogram F-104C (another Lockheed product by-the-way) in the tail at the far end of the exhaust pipe to replicate an engine. You can’t really see it and it’s not totally accurate but how many people really know what the inside of a tailpipe of a D-21 Tagboard Drone looks like?

It was time to glue the two halves together. Get your clothespins and clamps out. You will need them. Clamp, Tamiya liquid glue, clamp, glue, clamp, glue. Just like spot welding. Take your time and don’t use too much glue. These areas are thin from all that sanding. Two-part epoxy is an alternative, but you must be careful because when activated it is exothermic and can generate enough heat to melt the thinned edges. I might try thin or extra thin superglue you can wick it up between the two mating surfaces but you better work quick with this method. Once dry, I spent a lot of time thinning and filling the edges smooth. Be careful because the edge can actually get sharp enough to cut you!

The rudder section went through the same construction method. I did glue the two halves together and then put brass tubes in it to strengthen it and give something solid to stick into the upper fuselage. It was just a matter of matching the fuselage holes I drilled with the rods I superglued into the rudder and tail section. A finger full of Tamiya Putty got the area blended and just a little sanding got it smoothed out. I notices the area around the tail of the engine didn’t look like the reference pictures, so I added some fillet plastic and used Tamiya putty to blend in the new pieces much like I did with the tail.

The intake spike came in two pieces split down the longitudinal direction. It took a keen eye to get them sanded down to make a perfect cone. I ended up gluing a brass rod into the nose cone and then after it was totally hardened, I chucked it up in my multi-speed Dremel tool. I started off on slow with some 600 sandpaper and just used it like a lathe to get the round tapered shape more symmetric. Some putty was needed to get it completely cone shaped and more sanding while in the Dremel tool. I didn’t care about the brass rod I used to chuck it in the Dremel tool after I was finished sanding. I just left it in place. Then I glued small strips of plastic to shim the cone to the intake brass tube I had glued in place earlier so it would sit perfectly inside the intake.

I took two brass tubes and chucked them up in the Dremel tool and used a file to make two large, tapered probes that stick out at the front edge of the wings on both sides. They angle down a bit in their design on the real thing. I notched out two spots according to my references and drilled out that area. Then put a bend in each tube to match my pictures. It took a bit to get the downward bend and the alignment from the top to look right but you can really tell when you got it. Superglue and some Tamiya putty got them blended into the wings.

I used Tamiya X-18 Semi-Gloss Black since the theory is these things stayed indoors and were only flown once so there was no time for weathering like the museum pieces you see. The black paint coating would be in good condition and the entire aircraft would be fresh even years after it was built. I noticed that I did not get the surface sanded smooth enough and the semi-gloss black was very good at showing every scratch and flaw. So, it got sanded down again, polished and resprayed to a much better result. I really like using Tamiya paint with their lacquer thinner. One thing about the real article is that it was smooth by design. The panel lines were light and intentionally very smooth to keep radar reflection and aerodynamics at a maximum.

Then I used some decals from the decal dungeon to give it an identity. There were a few period reference photos that show these numbers on the nose but for most part they were all just painted black with no other markings at all like we are used to seeing. I also noticed the numbers ranged in size. I picked the largest numbers I saw in my references. To make this model be just a little more than completely black I felt the white numbers would break that up a bit.

I had an old trolly stand from a Testors U-2 kit and thought it could be modified to represent the D-21’s unique tow vehicle. So, I took it apart and filled and sanded in all the holes along with removing any extra boxes that shouldn’t be there. I added the small stabilizing wheels to each rail in accordance with my references and made a tow bar from an old piece of square brass tube. The loop at the end of the tow bar is just guitar string I looped and dipped in Tamiya primer to smooth it out a bit and superglued to the end. I bent some plastic strips to represent the tilt function of the trailer and glued them into place. I also noticed in my reference photos that they painted these trailers a light blue. Unusual but I think special purpose aerospace ground equipment during that time got that color since its intended use was for only one vehicle. I am sure a reader would know the answer. After it was all said and done, I could have totally built one from scratch and probably had less trouble than modifying the U-2 trailer. Not to mention the scratch built one would have been more accurate!

For someone who is interested in building a vac kit, this might be a good one (if you can find them.) It is simple but has a few items you will have to be creative with. The tow dolly, pitot tube probes, aerospike nose. But you get an interesting plane in the end. I never was satisfied with the exhaust grills on the top of the drone. I might investigate tank photoetch or ship radar photoetch to see if there is something there to modify and use. If you were so inclined to take it a step farther and modify a Testors SR-71 into the M-21 with the D-21, You would have a showstopper for sure! So put the Tamiya super kits away and get your hands (and hair, clothes and floor) dirty and try your skills out on an eccentric subject that only comes in vacuform.