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Wing loading is a term associated with the total weight the ram-air wing must support. Wing loading is found by dividing the total weight of the aircraft, in pounds, by the total area of the wing, in square feet. Wing loading is found by dividing the weight of the aircraft, in pounds, by the total area of the wing, in square feet. For example, the wing loading would be 2.0 pounds per square foot when 1,000 pounds—a common weight for a two-seat PPC with two people — is under a 500-square foot wing. If flying with one person the aircraft weight might be 700 pounds and the wing loading would decrease to 1.4 pounds per square foot. 

Gliding flight  is flying in a descent with the engine at idle or shut off. 

## Powered Parachute Wing Pressurization and Flexibility 

The powered parachute has two distinctive modes: (1) inflated, it is a  ram-air wing with a curved arc—a rec- ognizable airfoil shape; and (2) deflated, it is a canopy that is either lying flat on the ground or packed into a bag. 

Note: Chapter 7, Takeoffs and Departure Climbs, will detail the methods of getting the uninflated canopy laying on the ground turned into a flying wing. Since the aerodynamics of the PPC do not start until the wing is completely inflated, this chapter will assume each reference to the PPC wing is to an inflated ram- air wing already in the shape of an airfoil. 

The powered parachute ram-air wing retains its air- foil shape due to the air pressurizing the inside cells via the relative wind airflow being rammed into the front openings of the canopy —thus the term “ram-air wing.” The pressure inside the wing is much higher than the outside top and bottom because the dynamic pressure from the relative wind is converted to static pressure to pressurize the wing. The greater the speed, the greater the pressure inside the wing and the more rigid the wing. The cell openings are designed to be perpendicular to the relative wind to achieve maxi- mum pressure from the relative wind. This static in- ternal pressure harnessed from the relative wind is called dynamic pressure (q), and is determined by the velocity squared times the air density factor. [Figure 2-7] Note the dynamic air pressure converted to static pressure at point A is constant throughout the wing points B and C. This static pressure is always greater than the pressure outside the wing at points X and Z. 

Cross-port openings are placed in the ribs of each cell, connecting the adjoining cells. These cross-ports are dispersed throughout the wing (with exception to the outboard side of the end cells) to maintain positive pressure throughout. The pressure is constant inside 

