What is Aerospace Engineering? (Aeronautics)

this video is going to cover a summary of aerospace engineering specifically aeronautics and what this major entails as well as careers like I said in the other video aerospace can be broken up into aeronautics and astronautics where Aeronautics is about things that fly in the air and astronauts is about things that go into space now as you can imagine aeronautical engineers can work on planes helicopters missiles unmanned aircrafts fighter jets and so on but because this discipline is big on aerodynamics you could see aeronautical engineers working on cars and how to shape them to maximize their fuel efficiency they can work on boats which interact with their bullet trains which can go up to 200 miles per hour I'm sure many of you know if the Hyperloop that's being worked on right now which would be a mode of transportation that would propel people in a pod like vehicle through a tube at maximum speeds of almost 800 miles per hour well this needs aerospace engineers as well because that speeds that high there's a lot of air flow issues that need to be accounted for in that too so make sure when you think of aeronautical engineering to think of the various applications it applies to and also like I said astronautics video there are many subfields that you can dive into when it comes to air or spacecraft where you work on a more specific aspect of the vehicle some of the big ones I'll talk about our aerodynamics propulsion controls and stability and structures so first aerodynamics is of course where you've studied the properties of moving air and also its interaction with solid objects after you go through the basics of fluid mechanics like water moving through a pipe you get into the actual aerodynamics and you start with subsonic flow which is air flow that is less than the speed of sound and the speed of sound is called Mach 1 the planes we ride on helicopters and certain types of military aircrafts are all subsonic aircrafts the planes you go on are typically mach 0.8 or around 600 miles per hour well the speed of sound is about 770 miles per hour so first you learn airfoil theory which is just the theory behind air foils their shapes and how they produce lists to big aspects of these you'll analyze our list and drag when you have an aircraft there are four forces acting on it thrust provide by the engine which is left for propulsions lift which is due to complex interactions with the air and the wing drag which is basically friction from the air and the weight of the vehicle due to gravity so you'd see how those air foils like on the left provide a certain amount of lift and drag based on their shape and then the physics of that fluid flow and interaction you may be given some random object that's traveling through the air and asked to find the drag on it or the pressure at different points also when it comes to wings what angle is the best for optimum lift and less drag at some small arbitrary angle you see how air splits at the front and then follows the curvature of the wing this is ideal but if we increase the angle too much the flow become separated at the back and that's what we call a stall where the drag increases and the lift decreases which obviously is not what you want while on a plane there's much more to this because if you've been to air shows you seen claims that even fly upside down so just know this is a very very basic then you move on to supersonic aerodynamics this is where aircrafts move faster than the speed of sound these are mostly military aircrafts like fighter jets that are meant for defense purposes and no defense is a huge sector for aerospace engineers to get into so what happens at these speeds well I'm sure many of you know of the Doppler effect whereas the source is moving and emitting noise the relative frequency increases for objects in front and decreases for ones in back the sound lights basically are closer to each other in the front and the frequency goes up which is why a motorcycle sounds different approaching you compared to driving away from you now what about at the speed of sound well if we move slower than sound the waves can be drawn circularly like this and are closer together in the direction of motion but not on top of each other then at the speed of sound they actually bunch up on top of each other or constructively interfere this combining of sound waves in front is extremely loud and is known as a sonic boom which can break glass and shake windows while thousands of feet in the air then what about an object traveling faster than sound well then the waves are created but are trailing the aircraft there is still a sonic boom but the waves combined construct at an angle here rather than in front so they might give you that angle of the shock wave which is what that's called and asks you to calculate the Mach number or speed that the aircraft is flying at the faster the speed the smaller that angle and that's something that we can calculate now supersonic speeds the drag on the aircraft also increases much faster as the aircraft speeds up to compensate for all this supersonic aircrafts are made to be more narrow and have a sleeker look to them then there's also hypersonic flow which I'll talk about soon but this is for aircraft traveling at Mach 5 or higher which is just under four thousand miles per hour to put that in perspective you could fly from Los Angeles to New York and just under 40 minutes as opposed to five hours in your career two big things you can do our design or testing if you design you might be developing the aircraft wing on the computer and use computational fluid dynamics which I've shown before then you could simulate how we'll respond to interactions with the air as you saw designing a supersonic or hypersonic aircraft can be much different than the subsonic one the higher the speed the more challenges you face or you can do testing using a wind tunnel for example where you put the physical structure in a large tunnel and run fast winds through it to see whether it behaves like the computer simulation predicted in fact for a lab one school did parachute testing in a wind tunnel where they tested various parachute shapes to see which was the best but again this can apply to cars bikes and other vehicles that all need to account for aerodynamics now let's move on to propulsion this is where you obviously learn about the different types of propulsion systems used for an aircraft the big ones you'll probably learn are the turboprop turboshaft turbofan and turbojet so here's a picture of a turbojet and this is basically how it works air comes in the front as the aircraft moves it's compressed or squeezed through many rotating blades which adds energy to the fluid which causes its pressure to rise then fuel is added and it's lit on fire in the combustion chamber then that travels through a turbine which provides energy back to the presser and then the air exits out the back at a fast speed and high temperature to provide the thrust to the aircraft but if you look at the turbo shaft turbofan and turboprop you'll see they look very similar the overall concept of these isn't much different I'm sure most you've seen the propulsion system on an aircraft at least the outside of it all the things just list it or what's going on on the inside to learn the aerodynamics of the spinning blades and the compressor which like I said it can have a lot of stages to it you'll analyze the interactions of the fluid as it moves through the various stages you'll analyze the efficiency of the blades how do you minimize the amount of blades needed to analyze horsepower and much more again you may design these on the computer in your career or you do testing on them to see if all the specifications are met those aren't the only jobs but are two big ones but what about for supersonic aircraft at supersonic speeds that are high enough the engine doesn't require a compressor or a turbine here for reasons you'll learn about that relate pressure and temperature of the fluid if you remove those we have what is called a ramjet these are best used for aircraft flying between Mach three and six supersonic aircrafts like I said experience much more drag at those high speeds meaning the air is pushing back on the aircraft to slow it down more therefore you need an engine that can supply the right amount of force to compensate for this supersonic aircrafts also fly at extremely high altitudes at those altitudes the air density is much lower the engines must be able to compensate for that and intake large amounts of air because after all that air is what's making the propulsion work then what if you want to get well into hypersonic speeds well in this case you use a scramjet and we actually don't know the maximum speed that these can go it's maybe you're considering a master's or even a PhD and you want to do research on propulsion systems this is something you could do research on hypersonic engines one University while back put a model of a scramjet in a tunnel then added a hypersonic flow and measured the overall force they found that the scramjet was able to provide more thrust than the drag it was subject to meaning this was able to literates successfully and overcome drag which at high speeds is not easy to do and research is still being done theoretically we predict these can travel somewhere between Mach 12 and Mach 24 but we haven't gotten there yet so if you want to dive into propulsion research and get us to much faster speeds this is something to look into but remember most jobs will involve designing and testing already known propulsion methods now let's go over controls and stability this is essentially about using inputs than doing mathematical modeling to produce a stable and desirable output for example aircraft have autopilot on them the pilot may input a certain heading or direction and the aircraft control system has to be able to keep the plane headed in that direction if you enable autopilot you wouldn't want a really fast and abrupt change because that may cause this comfort you want a smooth transition to put the aircraft on the right course all this is about making sure the control system produces stable outputs from the inputs it receives so one big thing you'll learn is coordinate systems for the aircraft if an aircraft is moving forward we may call this the X direction which is parallel to the ground and this the Y direction which is the direction of gravity all this seems pretty convenient but what if the plane is increasing in altitude should we keep everything the same or maybe we could label the way it's pointing as X not parallel to the ground like before but it's still convenient here and then perpendicular to that would be our Y but also our plane might be going in this direction even though the nose is pointing slightly higher and this is something important to note the plane doesn't always go in the direction it's pointing in fact you're just looking at a picture right now for all you know this plane is falling out of the sky while pointed slightly up so don't get confused about this and by the way the angle between that relative air flow and where the plane is pointing it's called the angle of attack when that angle gets too big that's when the plane stalls remember the picture from before of the separated airflow as you can see this would be like the plane moving to the left then trying to go up by pointing its nose at an angle which would make that angle of attack too much in this case and that's why you see that it's then at that blue line we call our x-axis then perpendicular that would be the y-axis which is also the direction of list and perpendicular to that which would be the negative x-direction is drag so this is also really convenient especially for when you have to sum the forces in the X and y direction which you will do to derive various equations of motion because lift and drag are already in the right directions none of the systems are perfect but they have their advantages so you'll be doing lots of coordinate system transformations and defining multiple axes for a given aircraft like shown above and more and hopefully you're also seeing that yes aerospace engineering is a very math heavy major three of the most fundamental axes you'll learn about are yaw pitch and roll these are the three axes by which an aircraft can be rotated so as you can see roll is what happens when an airplane starts turning and it rolls to one side pitch would make the plane point more up or down and yaw would turn the nose side to side so how does this happen well when a plane turns or rolls the flaps on the wings move in opposite directions causing air to push one up and one down which causes a rolling motion for yaw a flap on the back or rudder turned side to side providing a torque about the plane allowing it to turn and for pitch the two flaps near the rudder are turned in the same direction which will force the back either down or up and therefore the nose to go up and down respectively and thus you have three ways to rotate a plane and guess what it's the control systems have to make sure these changes in direction are handled carefully you don't want to turn the flaps too much or the plane will roll too far which would obviously be a huge issue if the flaps change the pitch too much that could point the nose too high which will increase the angle of attack and that can cause the airplane to stall the control system keeps these all in check it's not like you have a rope attached to the flaps where you manually pull for these aircrafts you're seeing there's an entire system that has to work just right the control system is even used simply to drop those masts you see on planes the system has an input of pressure from the cabin area has to open the compartments immediately if pressure has changed too much we also have unmanned aircraft so obviously those need really good control systems as there's no direct pilot on the vehicle one area of research being worked on is flexible wings as in wings that can morph and change their shape during flight this is being investigated by NASA as an example to greatly improve flight efficiency and performance control systems would be required to change the wings during flight as needed now you take very similar controls classes to an electrical engineer because this is a field they can go into as well so if the controls aspect interests you the most you could also choose electrical engineering and search for aerospace jobs you can see in other majors like mechatronics or even computer science but Electrical is a very common one now let's move on to structures this is pretty much the same as this for astronomical engineers in fact you may take the same required courses when it comes to structures this is all about what you'd imagine making the structure of the vehicle so that it can withstand all the forces it's subject to during flight the wings are subject to a lot of force there are vibrations that occur turbulence happens and the aircraft has to be able to handle all this the basics of this involves learning about strings how structures experience the Teague over time deflection and how something bends when given a certain force shearing stress torsion and all types of forces that the structure can be subject to that I've shown before or what you'll be studying although you diverged into specifically aerospace classes you'll begin just like mechanical and even civil engineers taking all the same classes as them in your career could work on designing the structure of the wing so instead of making it aerodynamics you're more concerned with can it withstand two aerodynamic forces without braking or may you could work on the structure of the cabin those walls are actually thinner than you may think and need to be designed just right and this is also a career you could see mechanical or even a civil engineer doing because they learn a lot about structures in their curriculum overall as an aeronautical engineer you'll take a bunch of classes that cover the basics of everything some basic structures classes propulsion controls and more then you can dive more into one of those if you get a masters and there are more subfields and then talk about like design which is more about analyzing the aircraft as a whole and choosing the proper landing gear what engine to use the passenger cabin and so on more broad and less technical than some of the others or you can even have the option to take further material science or engineering classes I didn't mention this but at supersonic speeds the friction from the air molecules gets so intense that it can cause the aircraft to heat up to several hundred degrees Fahrenheit a materials engineer may have to work on this and choose the materials that can handle those temperatures but it's possible that an aerospace engineer could as well and I'm going to end there remember aeronautical engineering can encompass more than you may imagine when it comes to careers so be sure to look into everything if you'd like this video don't forget to Like and subscribe and I'll see you all next time

Channel: Zach Star

Views: 833,263

Keywords: majorprep, major prep, aerospace, aerospace engineering, aeronautics, aeronautical engineering, what is aerospace engineering, what is aeronautical engineering, aerospace engineering careers, aerospace engineering jobs, careers in aerospace engineering, aircrafts, aircraft design, aerospace engineering major, major in aerospace engineering

Id: JHfI5JbiWhE

Length: 16min 22sec (982 seconds)

Published: Thu Jun 22 2017