Manual lofting of 90-degree elbow

1, 90-degree elbow can be made into 4 shrimp loins or 5 shrimp loins, and the principle is the same when paying off by hand. Now, taking three sections as examples, let's talk about manual lofting.

2. Draw the main view (as shown below).

3. Each section of the waist bend can be twisted and aligned to form a straight tube (as shown below). Since the first section and the last section are half of the middle section, only the first section needs to be expanded.

Turn left | turn right

4. Divide the circular tube into 12 equal parts, and lead the bisector to the tangent point of the cutting line.

5. Expand the bisector from the point 1 to 12 and draw 12 vertical lines upward. After measuring the height from each point of the first part on the left, intercept them on the corresponding vertical line. Connect the obtained points smoothly to complete the flat pattern.