How can gliders fly without propulsion | The most complete explanation

Gliders or sailplanes are a kind of aircraft that differ from the rest by their ability to fly great distances without the need for an engine or propulsion of any kind even gaining altitude during their flight but, how is this possible? That is what I will answer today in this video. Welcome to Joyplanes RC 2. [INTRO] Personally, gliders are my favorite aircraft because they don't need an engine to fly and because of the long impressive wingspan they have but their long wings have a reason to be. Let's start with the basics we know that an airplane can fly or glide without an engine but in the process it will gradually lose altitude and depending on its weight aerodynamics and other physical facts it can go down faster this happens with every airplane regardless of whether they are gliders or not without an engine it is possible to fly for some distance and land as long as a constant speed and descent rate is maintained to be in a stable flight but the gliders are designed to take full advantage of this balance of forces the gliders are made with lightweight materials and the weight is distributed at strategic points in an efficient manner to improve air penetration and the configuration of their wings allow them to have more lift with less aerodynamic drag as a result their glide ratio is one of the most efficient among all airplanes The glide ratio is the distance that the aircraft can travel in respect to the lost altitude for example a Cessna 172 has a glide ratio of 9 or 9: 1 which means that if its engine stops working it can fly from 100 meters of height for about 900 horizontal meters in modern gliders this gliding ratio can be between 40: 1 to 70: 1 which means that if a glider has a 50: 1 ratio then it could fly for 50km if it starts at 1km high making it capable of covering long distances in this way Still it is impossible to gain altitude for an aircraft that moves through a static atmosphere without the use of propulsion of some kind luckily our atmosphere is not static at all to gain altitude gliders can take advantage of various atmospheric phenomena There are three main phenomena the ridge lift thermals and wave lift Thermals are the most mentioned way to gain altitude in a glider these are columns of hot air that is generated by a surface heated by the sun this air becomes less dense than the surrounding air and begins to rise rapidly the glider when entering a thermal can begin to fly in a circular pattern to stay inside it and gain altitude until the thermal disappears or weakens the other way to gain altitude is with the ascending currents of air on the slopes of the mountains this is simply air that is forced to climb the mountain and a glider can take advantage of this current to gain or maintain altitude the closer to the slope the stronger the climbing rate the last form is the use of air waves that are generated after the air passes through the mountain these waves extend for several kilometers and are invisible waves similar to the waves of the sea Using these strategies to gain altitude a glider can stay in flight for many hours this is totally free and clean energy that glider pilots gather and manage to get the most out of it However to make a glider take off you need an airplane that will tow it to an acceptable altitude where the glider can start by itself another way is to take off with a tow winch from the ground but the altitude that it gains is not as much as that of the first method hopefully on a sunny day the glider can take a thermal that makes it fly longer others Wways to take off a glider is from a mountain with a system of elastic ropes on a hillside or by having a retractable propulsion system integrated into the glider that is only used to take off or gain the altitude needed Why long and thin wings? the thin wings generate less induced aerodynamic drag than the common wings that are seen in self-propelled airplanes this way the glider can pass through the air with less difficulty obtaining the same lift and losing less speed than other airplanes another factor that helps for better Aerodynamics is the design of the fuselage making everything as smooth thin and aerodynamic as possible which is why the pilot enters the cockpit in much the same way as a Formula 1 driver in his car (almost lying down). the wings are also measured by aspect ratio glider wings have a high aspect ratio and war airplanes wings have a low aspect ratio war or acrobatic aircraft wings generate more induced drag than thin wings of gliders but because they are short wings they are more maneuverable maneuverability is a priority in warplanes rather than fuel efficiency in the case of gliders it isn’t necessary to make quick maneuvers so priority is given to efficiency sacrificing maneuverability The wings end up being naturally long because a large wing area is required with the restriction of a reduced cord wing to minimize drag Gliders are built to be very light but strong at the same time they even become so light that you have to put more weight on the wings to improve their penetration and speed characteristics this is done by filling the glider with water ballast in special tanks inside the wings the total weight of this ballast can be even higher than the pilot's weight the water can be drained during the flight in case the thermals are not so strong and must also be drained before landing In the beginning gliders were made out of wood with fabrics or metal and then the use of composite materials Fiberglass carbon fiber and kevlar was introduced achieving a huge resistance with a very light weight Flight instruments Gliders are equipped with the basic instruments that can be found on any other aircraft except for flight instruments associated with the use of an engine the most used and necessary instruments are the anemometer Altimeter Variometer and compass You can also find a turn coordinator Sometimes an accelerometer and tools such as a radio and a GPS One of the most basic indicators that are still used even in high-performance gliders is the yaw string it is a small string that is placed on the outside in front of the pilot that indicates the wind direction in regarding to the glider flight if the string is not centered it must be corrected using the rudder and that way the pilot makes sure that he is flying efficiently Otherwise that means that the fuselage is off by some degrees in respect to the flow of air and that generates a lot of drag It is important to be aware of the speed at all times since if the glider gets to slow than recommended it is possible to lose some control and go into a stall also depending on the design there is a specific speed in which the glider has the maximum efficiency between descent and distance traveled to measure the speed at which the glider goes with respect to the wind the anemometer is used the airspeed is different from groundspeed the variometer indicates the speed of climb and descent this instrument is super important to know when the glider is beginning to climb usually when it enters a thermal and thus stay within the thermal the gliders are equipped with a system that generates a sound depending on the speed of ascent or descent with this sound you can more easily identify if the glider is going up or down without having to look at the indicator all the time as you have already seen in this video gliders are a very interesting type of aircraft especially because they don’t burn any type of fuel to stay in flight only the natural energy available in air currents nowadays gliders are used for sports and recreational purposes I give special thanks to Stefan Langer who is a glider pilot you can see his channel in the description of this video Making the animations the editing and post production in general of this video has taken me a couple of months it would be great if you could support me through a small donation link in the description or even a like and share is also appreciated also consider subscribing to not miss more videos like this or videos in which I make rc airplanes drones or similar projects for now I will see you in the next project

Channel: Joyplanes

Views: 3,738,640

Keywords: joyplanes, joy, planes, joyvel, how to, airplanes, radio control, RC, drones, gliders, sailplanes, flying without engine, gliding ration, long wings, flight, glider pilot, how glider fly, how to fly without anything, flying plane with dc motor, glider speed

Id: b4YrpmhgNGs

Length: 10min 17sec (617 seconds)

Published: Thu Aug 22 2019