Parachutes and Energy Management
Basic Physics divides energy into 2 forms. Kinetic energy is the energy associated with motion (think of moving snow in an avalanche). Potential energy is associated with a stationary object, that could begin to move (think of the snow on a mountain just before an avalanche). So when an airplane's engine dies, it has a bit of both. Forward speed = Kinetic energy. Height above the ground = Potential energy. The key is to dissipate this energy as much as possible before rudely contacting the ground.
Initially, Parachutes seemed like a good idea when the airplane could not be controlled well (most pilots prefer to fly their aircraft over a parachute). Thus parachutes began their existence as a safety device designed to merely dissipate Potential Energy.
Round parachutes do an exceptionally good job of bleeding off this unwanted energy. Through simple drag, they permit the parachutist to get rid of Potential Energy while limiting the Kinetic Energy. This permits a survivable landing. Of course, survivable does NOT imply fun... These devices can still have an annoyingly high descent rate.
Square parachutes permitted Aerodynamic Lift to replace Aerodynamic Drag as the principle force that dissipates the unwanted Potential Energy. Big, fat airfoil sections mirror the effects of round parachutes. They limit both the forward and downward speeds, thus limiting the Kinetic Energy. They also permit the jumper to convert the downward Kinetic Energy into lift. When timed correctly, this facilitates wonderfully soft landings. When timed poorly, the jumper can fall out of the sky faster than if under a round.
That downward speed and resulting Kinetic Energy injures people. It must be avoided at all costs.
Parachute designers started then taking their cues from airplane wing designers and eventually created the modern, elliptical parachutes. These creations still can dissipate Potential Energy, but really excel at converting Potential Energy into Kinetic Energy. When accelerated towards the ground, these wings do NOT dissipate energy, they maintain and convert it to Kinetic Energy.
The modern canopy pilot thus has more energy available to outwit gravity. Plus, even if landed poorly, a jumper can still arrest virtually all downward speed. Rolling across the ground, bleeding off forward speed sure beats dropping into the ground with a high vertical speed. No one appreciates slamming into the ground.
Thus, inducing speed to land a BASE canopy will give the jumper more options, PROVIDED ENOUGH OBSTACLE CLEARANCE EXISTS. This energy maintenance style approach will give the pilot more options.
Some tight landing areas can still demand an energy dissipating approach.
The best jumpers can do either. It's all about spending the energy in the most productive fashion.
BASE
Make your choice.
Be prepared to deal with the consequences.
