- Sports and Recreation
Terminal Velocity and Drag
Humans have long dreamed of flight and we do it with planes, but lately we have donned sutits that allow us to glide through the air.
of Bumble Bees and Human Flight
Terminal Velocity is something that those who sky dive know a lot about, but the general population is not as familiar with the basic idea. Modern aerodynamics exploits this principle to a great degree, what with parachutes, para-gliders and the like. Most people have been are also familiar with the idea of gravitational acceleration, where two objects of different mass will fall at the same rate. Then there is the question that is often cited as proof of the existence of a creator and that is the ability of the bumble bee to fly when it is not aerodynamically suited to do so. What we have here is a combination of factors that examined under a complete analysis, have a logical answer. Thus the bumble bee cannot be used as a proof of a creator from that point of view. This in itself is not an argument against god, but against sloppy science. Whether or not science can prove the existence of a creator is one of the fields that are now the object of research. Questions of proof have to do with the field of consciousness and existence.
Consider for a moment that the existence of an atmosphere will alter how something will "free fall". We see this all the time. If you live where dandelions or cottonwood grows, you are familiar how the seeds are distributed by being wafted through the air in the gentlest breeze. They are actually falling very slowly due to atmospheric resistance and on how their mass is distributed. That is because they have a wide distribution of mass and this is also very small. On the other hand, something like a human being will free fall rapidly due to a much higher mass and compactness. But even human beings have an upper limit of free fall due to atmospheric resistance. That limit by and large is about 135 Miles per hour. But hitting the ground at that speed is like being stuck by a car on a raceway. The result in both cases is severe trauma and death by impact. Atmospheric drag will not allow for a faster rate of fall in the lower atmosphere. In a hard vacuum, everything dropped toward the Earth will accelerated at 9.98 ft/sec^2. This means that a free falling object will continue to accelerate indefinitely until stopped, usually by contact with the ground.
Galileo did an experiment with a feather and cannon ball in a vacuum and found that they fell at identical speed and hit the ground together when released at the same time at the same height. The experiment was repeated on the moon by an astronaut during one of the Apollo missions to the moon with the same result. When released within the atmosphere, the cannon ball hits first and the feather much later. Now masses on Earth will fall differently due to atmospheric resistance, which is why the cannon ball falls faster than the feather.
Consider that small fluffy objects will fall more slowly due to a lower terminal velocity in the atmosphere. This is why dandelion parachutes and cotton wood fluff drifts lazily in a light breeze and takes considerable time to fall even a few feet. Humans and cannon balls have a much higher terminal velocity and fall much more rapidly. Birds and flying squirrels will change body shape to reduce terminal velocity or fly as in the case of birds.
Sky divers know that when they free fall, they will reach a terminal speed where they will not fall any faster regardless of the physics of free fall in a vacuum, due to atmospheric friction and resistance called drag. Indeed, by altering their shape like spreading their arms, sky divers can reduce their terminal velocity a little. By opening a parachute, they reduce it a lot, approaching the landing speed of lighter, more spread out mass objects like feathers.
In a tornado and hurricane of sufficient strength, houses, cars, trees, animals and people can become airborne and carried a considerable distance. With high enough winds, even rocks and small boulders can become lifted into the air. To reach terminal velocity, all that is required is to reach the limit that atmospheric drag imposes upon any object in free fall. In order for something that normally does not become air-borne, all that is required is a wind of sufficient velocity to produce a condition of terminal velocity to cause lift.
The flight of the bumble bee that is not aerodynamically designed works because the bee is a small mass creature that can reach terminal velocity much more easily with small wings than something like a cat, a dog or a person. A bumble bee's terminal velocity is much lower than that of a human being. In the atmosphere, the bumble bee can fly with small wings and an aerodynamically awkward shape due to its low terminal velocity. In effect, the bee can fly due to a combination of various laws of physics such as drag, terminal velocity and aerodynamics on small scales. This same combination of factors allows insects of all kinds to fly. However, the lower terminal velocity has a negative side. Such creatures find it impossible to navigate to a specific destination in a high wind. People have no trouble walking in the wind unless it reaches the speed of a gale or hurricane. But this fact tells us the people who take on flight must do so with large wings and a great enough speed to achieve lift.
Terminal velocity is a key that gives us a clue to minimum requirements to achieve human flight without airplanes. Lately, extreme sports enthusiasts have been designing suits that approximate the appearance of flying squirrels and sugar gliders. Flaps extend from the wrists to waist and a “tail” flap between the legs to the ankles and these sports enthusiasts leap from high cliffs, mountains and palnes and literally glide through the air relying on drag that is directly related to terminal velocity. The arms and legs are extended to maximum separation to create a wing surface with the suit flaps. These sports enthusiasts prove that human gliding is possible based on lowering the speed of terminal velocity by spreading out mass much like a flying squirrel or sugar glider. Near the end of flight, these sports enthusiasts deploy a chute for the final descent. One of the goals of these human gliders is to go for maximum distance by gliding alone. Others prefer to do complex maneuvers in the air.
Here are some clear views of human gliding in action
Continuing in the vein of awesome!
Flying through a cave in Chine!
Not Everything is as it Appears. This was Unfortunately, a Hoax
The Man Who Hoaxed Human Assisted Flight
- Human Birdwings | Building a semi human powered flying device
This page describes the development of human assisted flight where the muscles are augmented to bring us closer to true and fully human powered flight.