I immediately began to determine the scale of the model I wanted to build. I researched schematics of B-29s and found the dimensions and specifications. I wanted it to be roughly to scale to a LEGO person, so it would have to be about 140 units wide and 100 units long - about 4 ft x 3 ft. As with most scale models, the size is not the hard part - I can always buy more pieces! The major challenges I faced were with the landing gear, the propellers, the wings, and the cockpit.
My biggest challenge was the landing gear. I wanted to make them
retractable, yet be strong enough to hold the weight of the model. Of
course, at this point, I had no idea how heavy it would actually be - I
could only estimate. Half way through the project, I discovered that my
estimations were off when the landing gear buckled, so I had to
completely remove them. I decided to leave them off until I knew the
full weight of the model. I created some temporary supports in place of them while I continued building it. Below is an early prototype or mock-up of the
right-hand side landing gear.
I had to overcome all of these challenges while still creating a frame, wings, and a fuselage that were strong enough to hold their own weight. I sketched a few drawings (below) of what the interior framework of the wings and fuselage would look like to ensure it was strong and that the wings could accommodate the wheel bays behind the #2 and #3 engines. The "skin" would then fit around the frame to give it shape while also adding to its strength.
Next, I had to capture the B-29's iconic tubular fuselage and rounded cockpit. This was difficult as most traditional LEGOs are not rounded but have sharp angles. I needed to be extra creative. I eventually came up with a design that utilized hinges to make the rounded shape for the cockpit, while also serving as the web-like panels in the windshield. I also had to purchase more pieces to create the smooth, curved edges for the fuselage and the engines.
In the photo above, I've just finished the frame and most of the "skin" is already in place around the wings. Below, the fuselage is mostly complete.
Even though the proportions were all accurate, the model was back heavy so it leaned back, as shown below (you can also see the temporary supports in place of the landing gear). A real B-29 is better balanced towards the front, mainly due to the weight of the engines. I had to add more weight to the front of the model to balance it.
.JPG)
My next challenge was to make the propellers rotate in unison. (First, as a side note, I had to do a bit of research on this as to whether all four propellers on a real B-29 rotated in the same direction. In some twin-engine planes, the props will rotate counter to each other to prevent torque steer which is present in single-engine aircraft. I eventually discovered that all four of a B-29 engines rotate the same direction.) I placed a rod through the wings that connected to gears that drove the propellers. I also geared it so that turning the nob slightly would rotate the propellers quickly, giving it the "flying in mid-air" effect.
