The parachute It is a device designed to reduce the falling speed of a body, increasing the resistance of the air. Today this tool plays a key role in various areas: from rescue In case of emergency to employment military, up to sport extreme. Handing in flight has always been an idea that fascinated the man: after all Leonardo da Vinci in “Atlantic Code“He imagined drawing objects for” with great lucidity for “float“In the air. According to the latest data of the United States Parachute Association (Uspa), the mortality rate reached the historical minimum in 2020, with only 0.004 deaths every 1,000 jumps. But how exactly does this tool work? And what are the main types?
What is a parachute and why it works
A parachute is a useful device to slow down the fall of a body by increasing the aerodynamic resistance. We are in the field of the mechanics of fluids whose fundamental principles will allow us to understand why and how a parachute works. In physics every aspect represents a game of forces that add up and subtract and, in the case of parachute, the same thing happens. The main factors at stake when considering a body in free fall are:
- there force of gravitythat is, the force that exerts a downward attraction and is proportional to the mass of the body in fall;
- there aerodynamic resistance (also calleddrag)That is, a force opposes the movement of the body down and grows with increasing speed.
When a paratrooper launches himself from a plane initially accelerates because of gravity. Its speed, as it goes down it grows and, with it, also increases the drag. This occurs until a balance is reached in which gravity and aerodynamic resistance cancel each other: the falling body will therefore have reached its own terminal speed.
Once opened the parachute acts by changing the equation of the movement, in particular by increasing the body surface. All this means that the surface of the body in fall that interacts with the air is greater and, ultimately, it generates greater resistence in the air, given that the drag increases enormously.
Main features and types of parachutes
A parachute does not reduce only to the most visible part – the cap – But it is a complex object in which geometries and materials affect in an important way on uses and performance. The main components are:
- there Calotta: the iconic part of the parachute. Designed to ensure robustness, stability and the best aerodynamic resistance;
- the Suspension lines: The cables that connect the shelver cap. Also made with high performance materials such as Spectra or the vectran;
- theIrabrago: It is the set of equipment worn by the paratrooper, the “backpack” anchored to the back, legs and abdomen;
- The container: Contains the main cap, reserve and the opening mechanism;
- The “Pilotino”: It is a small secondary parachute that, once extracted, contributes to the opening of the main cap “pulling it” out of the container.
Aerodynamic materials and characteristics
In the first models of parachute the silk And, although it could make us smile, it is a material appreciated for lightness and resistance. As you can easily imagine, however, it is one natural fiber subject to the effects of aging and difficult conditions related to use in parachutes (humidity, heat, cold, etc.), in addition to the obvious costs decidedly high. It was thanks to military research and the spread of synthetic fibers such as the nylon and the even more robust Kevlar (notoriously used within the bulletproof vests), which were made more versatile parachutes, robust and low cost.
Finally, a very important aspect cover the geometries of the caps because, to each form, it corresponds to use specific of the parachute. In general, there are two most common forms, the parachutes in hemisfera and the wing profile.
- The parachutes a hemisphere are characterized by the typical form a dome. Given their geometry mainly develop a force vertical But with little ability to maneuver. Normally they are used for purposes military Like the launch of supplies, materials or as parachute of reserve.
- The parachute ad wingon the other hand, are the parachutes rectangular. Their shape recalls a rectangle or, more properly, the wing of an airplane. They also have some air intakes they create lift necessary to exploit the friction of the air and glide as much as possible. They are widespread in parachuting sporty or in military launches operational which Halo (Halo (High Altitude Low Opening) And Haho (High Altitude High Opening)respectively jump from high altitude with low altitude opening or high altitude launches with immediate opening.
