Click on photos to enlarge.

 

 

 

 

 

 

 

 

 

 

In the late 1930s, the Douglas Aircraft Company designed Model 7B for the US Army Air Corps. The first prototype flew in 1938. After the Air Corps’ initial evaluation and because of a lack of funding, it decided not to purchase any 7Bs. The aircraft’s performance caught the French government’s eye, and it ordered 270 under the designation of DB-7.

     In late 1939, the US Army Air Corps reversed its decision not to buy any 7Bs and ordered 63 of the airplanes as the A-20. This model proved to be versatile, and the US and many of its allies used it in all theaters of World War II. More than 7,000 of the fighters were built.

     I had a lot of fun building my version of the aircraft. I modeled it in the color scheme that is on the A-20 in the National Museum of the United States Air Force in Dayton, Ohio. It was painted to represent an A-20G flown in the 5th Air Force, 312th Bomb Group, 389th Squadron in 1944.

     I used Flat Olive Drab and Flat Dove Gray MonoKote to cover my A-20. I painted the skull and crossbones on the nose. I wasn’t about to paint all those little bombs on the side of the fuselage below the canopy, so I took a photo to a local sign shop and had the bombs and the “Little Joe” under them cut from vinyl. I made all the other markings from a MonoKote Trim Sheet.

     I wasn’t interested in putting too much detail in the cockpit, so the only thing in there is a pilot. The gun turret has much more detail than the cockpit; I enjoyed doing the research and detailing that part of the airplane.

     When I started designing my A-20, I decided that I wanted to use round cowlings on the nacelle, to make the model look more realistic. Most of the companies that produce fiberglass replacement cowls for kits also have various sizes of generic radial-engine cowlings, so I went that route. I got them from Fiberglass Specialties. I don’t care to see a big, gaping hole in the front of the cowlings, so I installed vacuum-formed dummy radial engines from Dare Design and Engineering.

     My completed A-20 weighed 11.5 pounds, which resulted in a high wing loading. If you decide to build this model, I recommend that you use contest-grade balsa throughout. You can also cut lightening holes everywhere possible to keep the weight down.

 

CONSTRUCTION

     I like to cut out most of the parts before I start to build my models. If you have never built from plans, there are several methods to transfer a part’s shape from the plans to the wood sheets. My favorite is to cut the plans to the individual parts and then use a glue stick to temporarily attach the paper parts to the appropriate thickness of wood. Then I cut the parts.

     If I need to make more than one component, I use the glue stick to adhere a piece of scrap paper to the back of the part and then use the glue stick to attach it to another piece of wood. Then I cut both parts at the same time.

     Don’t use the glue stick directly on the wood; apply it only to the paper. Once the part has been cut, simply peel off the paper.

 

Fuselage: It doesn’t matter if you start with the wing or the fuselage; I like to build the fuselage first. Because of its size, you will need to edge-glue some balsa sheets. I try to make sure the splice for the sides will be in the area that the 1/8-balsa wing-root doublers will cover.

     When the sides are cut to shape, be careful; the joints will be fairly weak. But if you use the same method I do to cut the parts, the paper will help reinforce the wood.

     Lay the fuselage sides on the workbench, either top to top or bottom to bottom. This will ensure that you don’t make two left or right sides. Mark the locations of the formers and doublers on the fuselage sides. Glue the fuselage doublers to the sides. Then you can glue the 1/4-balsa triangle stock to the edges of the sides, as shown on the plans.

     Glue formers F2, F4, and F6 to one fuselage side. Make sure the formers are 90° to the fuselage side. Don’t glue the top of the side to formers F4 and F6 just yet.

     Adhere the 1/4-balsa triangle to the formers and the fuselage side. Lift the fuselage side that has the formers glued to it from the bench, and place it so it is sitting on its bottom. Place the other side in position so it can be glued to the formers. Before gluing the other side to the former, ensure that it is properly aligned to the other side.

     The wing-joiner-tube sleeve is next. First, I immobilized the fuselage by placing weights on the top of it.

     Insert the fuselage portion of the wing-joiner-tube sleeve in one fuselage side, slide the 1/8-plywood doublers over the sleeve, and then slide the joiner tube into the other fuselage side. Insert the joiner tube in the sleeve and adjust it so it protrudes an equal length on both sides of the fuselage.

     Measure the height at each end of the joiner tube. If the figures are unequal, enlarge the hole in one fuselage side until the tube height is the same. Use a carpenter’s square to determine whether or not the joiner tube is square to the fuselage sides. If it is not, enlarge the same hole in the side until it is.

     Slide the 1/8-plywood doubler up against the side with the enlarged hole and glue the doubler in place. Make sure the wing joiner tube is still equal in height to the workbench and square to the fuselage side. Glue the other 1/8-plywood doubler to the other side, and then glue the wing-joiner-tube sleeve to the fuselage sides.

     Carefully pull the tail end of the sides together and trim the 1/4-balsa triangle so the sides can be joined. Hold the ends together with a few clothespins without gluing the end, and then sight down the length of the fuselage and make sure it is straight. Adjust the sides as necessary until it is.

      
  back   forward