Drawing the vertical views (from the top and bottom) of the SBD Dauntless was more difficult than the side view, because there were no “vertical” photos which you can use to verify and enhance the available plans.
Anyway, I started using everything I could, for example some photos from the restoration done by the Pacific Aviation Museum (Figure 8‑1):
The photo on the picture above has a strong barrel distortion. We cannot effectively “revert” it as we did for the side view. Why? Because the photo of the side view all contours of the aircraft lie on a single plane (the symmetry plane). This one contains are at least three important planes: the edges of the cockpit, the center of the fuselage (along its maximum width) and the wing contour. Each of them is located at a different distance from the camera, and each requires different distortion (fixing one of them you would spoil the others).
Nevertheless, taking all of this into account, this high-resolution photo is still useful to determine the rivets pattern of the center wing section, as well as the width of the cockpit frame. The edge of the Dauntless cockpit is formed by an important longeron: it determines the fuselage shape in this area. To precisely estimate the width of the cockpit canopies I draw auxiliary contours of their cross sections (you can see them on the picture above as the blue lines). Positions of the bulkheads are copied from the side view. On this top view I roughly approximated positons of the longerons below the cockpit edge. This is just a “workshop drawing”, not a regular scale plan: I will form the fuselage following its contour on the side view and a few key cross sections which I will draw later. Because of the barrel distortion of the reference photo I was not able to check the contour of the fuselage in the top view. This is the only element I had to redraw without any verification from the Douglas general arrangement drawing.
In next step I used dimensions from the Douglas diagram to draw the trapezes of the outer wing panels and horizontal tailplane (Figure 8‑2):
Picture above shows all the lines which you can deduce from the general dimensions provided by the manufacturer. We can further enrich it using the information from the stations diagram (Figure 8‑3):
The station diagram provides precise position of all wing ribs. Most of them are just a row of rivets, but along some of them you can find the panel seams.
All right, but this wing drawing is still missing its “vertical” elements: rivet and panel seams along the spars and stringers. How to determine their locations?
I had to review all the collected photos. Ultimately I chose one of the pictures from the web page of Chino Planes of Fame Air Museum (Figure 8‑4):
I rotated this photo, aligning the wings of this airplane to the vertical guides. As you can see, it is made with a telescopic camera, so that it is very close to a perfectly orthographic projection. (The guides of the tailplane are not ideally parallel to corresponding guides on the wings, but this difference is minimal). The left wing is depicted at a relatively high angle, so you can see clearly the rivet seams along the spars and stringers. I decided that I can use this picture to map these lines onto my drawing.
I flipped this image from right to left, and stretched it, fitting its wing into the basic trapeze (Figure 8‑5):
It allowed me to recreate the wingtip curve. In such a highly-deformed image the rib lines are bent. They match their “true” positions only on the wing edges. However, we can easily map from this image the spar and stringer lines. All of them continue from the center wing section. Combined with the ribs these lines form a kind of the “reference grid”, which cells allowed me to draw all the remaining details: the circular holes in the flaps, fixed slats openings, etc.
I used similar method to map the tip of the horizontal tailplane as well as its two spars. In the effect I obtained a detailed top view of the SBD Dauntless.
In the next post I will publish the bottom view (I am just working on the last details).