- Vertical Tail (x2)
- Horizontal Tail
There isn't much to the design of these parts. That being said, they are also several considerations I need to cover, especially regarding weight, and the possibility of making the tail keep its self from dropping and causing a stall.
As a general rule, the tail sections are constructed using two layers of paper. That means the parts are measured with double the area, then folded in half to double the thickness. This doubling has a side-effect of extra weight. As demonstrated in the previous attempt at the P-38, this can lead to bad things happening. If this model ends up being tail-heavy as well, then I'll probably start by reducing the vertical tails to single-thickness, followed by the horizontal tail.
Vertical Tail(s)
The P-38 has two vertical tails. Like the engine booms, they're identical, so I only need to design one. I verified the scale of the bottom image on the spotter card by measuring the length of the engine booms. Luckily, the scale isn't changed--the booms on the bottom and middle images are both 245 pixels long, so the same scale can be applied to both images. This gives the vertical tail a width of 1 1/2 inches, and a height of 2 1/4 inches. To double the thickness, I'll make the part 1 1/2 inches by 4 1/2 inches. I could also make it 3 inches by 2 1/4 inches. The direction will depend on the efficiency of laying them out on the paper.
Horizontal Tail
The horizontal tail spans between and beyond the engine booms. Using the same scale, the tail is just shy of 6 3/4 inches. I'm going to use 6 5/8 inches. The width is 1 1/8 inches. Because doubling the horizontal tail long-wise would cause the total length to be longer than a standard sheet of paper, the final part's measurements must be 6 5/8 inches by 2 1/4 inches.
Regarding weight reduction, I may only reduce the weight of the tail by 1/4. I'll do this by essentially turning the horizontal tail into a second wing. By creating a thicker leading edge than trailing edge, it gains the properties of an airfoil, which will generate lift, which will keep the tail from dropping. You might ask why I'm not doing this as a first choice. Really, the tail isn't supposed to provide this kind of support--it is a stabilization and control surface. Also, mitigating a heavy tail is the reason for this re-design, so it's already in my sights. Hopefully, the changes I'm making will balance the model enough to avoid having to make the horizontal tail into a lifting surface.
Horizontal Tail
The horizontal tail spans between and beyond the engine booms. Using the same scale, the tail is just shy of 6 3/4 inches. I'm going to use 6 5/8 inches. The width is 1 1/8 inches. Because doubling the horizontal tail long-wise would cause the total length to be longer than a standard sheet of paper, the final part's measurements must be 6 5/8 inches by 2 1/4 inches.
Regarding weight reduction, I may only reduce the weight of the tail by 1/4. I'll do this by essentially turning the horizontal tail into a second wing. By creating a thicker leading edge than trailing edge, it gains the properties of an airfoil, which will generate lift, which will keep the tail from dropping. You might ask why I'm not doing this as a first choice. Really, the tail isn't supposed to provide this kind of support--it is a stabilization and control surface. Also, mitigating a heavy tail is the reason for this re-design, so it's already in my sights. Hopefully, the changes I'm making will balance the model enough to avoid having to make the horizontal tail into a lifting surface.
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