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Planform  is the shape or form of a wing as viewed from above. The PPC wing comes in two wing plan- forms: rectangular, and elliptical. [Figure 2-5] The el- liptical planform leading and trailing edges are curved to form an elliptical shape when viewed from the top or bottom. These two shapes have unique flying char - acteristics. Rectangular wings typically produce more drag, are lower-performance, and do not move fore and aft, relative to the cart, as quickly as elliptical wings. These characteristics are more obvious when the wing is inflating, during pitch changes, and when flying in turbulence. Rectangular wings are therefore more stable and require less effort to fly. Elliptical wings are higher-performance and more efficient due to less drag. Elliptical wings react more quickly with changing conditions and require greater pilot experi- ence and skill during inflation, in turbulent air, and with abrupt throttle changes. 

Aspect ratio  is the wingspan divided by the average chord line. A PPC with a common 500-square foot rectangular wing (about a 38-foot wingspan) and with a typical mean chord line of 13 feet, would have an average aspect ratio of about 3. This relatively low aspect ratio is less efficient at producing lift. An ellip - tical wing with the same 500 square feet and a 45-foot wing span and an 11-foot average chord would have an aspect ratio of about 4. The PPC wing is similar to airplane wings in that the aspect ratio will differ with the specific design mission for the aircraft. Generally, 

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rectangular wings have lower aspect ratios and lower efficiency than the higher aspect ratio and higher effi - ciency elliptical wings. Generally, a high aspect ratio wing, compared to a low aspect ratio wing, produces higher lift at lower angles of attack with less induced drag. [Figure 2-6]. 

