 All right this is the fuselage or the body and the various parts that are attached to it notice here the front of the fuselage you can see this yellow colored what do you think that is what would that be or what is it called I am talking about this part in the front. So this is something that you have to now figure out and tell me what it is what did you call that part this yellow colored part on the front of the fuselage let us look at types of fuselage this is the single fuselage type but can you identify the aircraft A380 why A380 how are you so sure but E1747 is double-decker and four-engine so you should have said that first full cabin length double-decker transport aircraft with four engines no need to say four engines there is no other aircraft even with zero engine there is no aircraft available today which is double-decker from length to the tail nose to the tail okay so this is the conventional fuselage this one is a twin boom now we will not go into the details right now why do we this is twin fuselage not twin boom there are two fuselages and notice there are two cockpits so who is the boss do you think there are two engines so are these two aircrafts welded together to save money think about it and then this is only fuselage no fuselage sorry only wing this is called as a blended wing body BWB this is the shape of the aircraft of the future what is expected is that in future the aircraft would be like that so these are type of fuselages okay let us focus on twin boom fuselage that was a vampire aircraft Cessna Skymaster and many many UAVs are like that available this is the twin Mustang and White Knight White Knight is very famous what does it carry not the space shuttle it carries something like a space shuttle it carries a small aircraft that can be used to give you a experience of near space flight it is a carrier for another aircraft what is it called come on you should know this is simple general knowledge okay I do not want to tell you look at the website of Virgin Galactic and you will get the answer there is designed by Bert Rutan okay this is UAV Pegasus X-47 this is also a UAV so what is meant by this APU auxiliary power unit so this is the location right on the back on the tail on the rear part of the fuselage this is where you normally see an APU in some cases you can clearly see the exhaust type of an APU so APU basically is a small engine separate engine and you can see now the APU has been opened up so it is a gas turbine engine that provides power for ground operations it runs at accessories and the systems when the engines are shut down and it also provides the power to start the main engine without APU you to start the engines you will need external power that means you have to depend upon the airport for providing that much power so APU is a small starter for the main engine okay now let us look at one scenario yeah on the sides of the fuselage there are small loops which allow the air to be sucked so it is not a jet engine it is a turboprop engine so therefore it just needs some air so there is a intake manifold normally on the side good any other question so let us look at this scenario during flight the two engines or four engines all have failed then the APU should help you out APU also has failed can it happen can happen okay this happened in the flight called Air Canada complete loss of power so what does the pilot do in this case yes what do you think so there can be catastrophe and safe landing so we have rat okay this is the aircraft is landed safely so this is what aircraft carry with them they carry an animal which will provide power no no rat is a ram air turbine the small turbine that comes down below when needed and it creates it gives the required use the required power so I have lost all the power and I do not have a rat with me okay so it generates power from the ram pressure of air stream the small fan which is mounted below this fan will start rotating when it picks up some minimum speed it will start generating power and the usual location of rat this is where the rat is you will see this is how it comes out and starts rotating and this is for the ground for maintenance purposes this is how it goes back inside so we also have something called as a tails kid is there yes ram air turbine yes so ram air turbine is only able to give a small amount of power which can only run the main functional components it cannot run everything so it will run only one hydraulic system which is required for safe landing it will not run air conditioning unlike APU it will not run other passenger entertainment systems movies etc may not run so it is a small turbine for emergencies for just the minimum power okay yeah but what is the option everything else has stopped working now I need something that works like a windmill purely on the function of the ambient speed of the aircraft and I wanted to be completely independent it should not be connected to anything so the ram is lowered by the pilot manually there is a ram deployment lever it is not deployed hydraulically because you can assume there is no hydraulic oil or no pressure available so sometimes there is a small wheel or there is a jack or a kind of a lever so they want a system which is completely self-sufficient which can bring the aircraft down safely in emergency yes it will power one of see an aircraft normally has three hydraulic systems okay we call them as yellow blue green so it will power one of the control systems which will be connected to the primary flight surfaces so it may move only one rudder only one inboard as a rounds okay may only move some flaps so it will be used to power only the minimum things required for a safe landing so therefore the power requirements are also limited all the emergency systems that you need landing air extension it will be powered by ram otherwise everything is fine but you cannot come now okay sometimes it does not work also sometimes it does not give enough power those things also happen but they wanted to have a system so that in case there is a situation then we have something okay so tail skid is a very interesting device obviously you can see that tail skid is essentially trying to what is it doing avoiding the rubbing of the fuselage on the ground and very costly repairs for which the aircraft has to be shipped to the manufacturer so what you do is you have a disposable kind of a skid it rubs but why is it needed why will an aircraft go at an angle such a large that the shooter will hit the ground when can it happen yes loudly please that means in a large aircraft routinely there is a tail skid which gets burnt away if I say that it is used mainly in landing then yes you already say it is not wrong it is correct but that is not the main driver yes loudly some kind of disturbance so this is not something that you desire to happen okay it is it is it is like a safety device okay when it happens this is a trial trial flight you can see it starts hitting the second run appears to be a success but with time pressing the ground crew races to the aircraft to discover that despite a more control takeoff the shredded skid will leave replacing once more unfortunately there's a limited number of the specially engineered skids available so the crew know that they could only afford so this is the tail skid which has got this portion which can be worn away and replaced but as you saw in this test even the rear fuselage end scraped a little bit and because of that they have to now change the skin change the skin on the on the bottom to use one skid the every two runs from this point on even the slightest error could put the entire campaign on standby this is that this is that skid which wears away and that wheel will will break and go inside the fuselage because of the high impact so they have decided that the best way to overcome a very bad situation even with the skid you saw that the the rear was slightly damaged but imagine if there was no skid then the whole of the rear fuselage conical thing would have to be changed yes no no the skid contains material which will wear away without damaging the runway so the it uses cork or some other such material it's a very interesting thing in fact it's one of the challenging materials to be used what is the material to be used so that the aircraft is protected but runway is not damaged so it's a very interesting material and lot of research is done in designing or identifying the suitable material for the tail skid device okay let's look at the red dome red dome is basically a cover it's like an SL again there is a radar inside the aircraft you put a cover over it it's called as a red dome and it has a antenna you can see the red dome covers this antenna this antenna is for which radar what kind of radar is this yes no it's not omni because it's not going behind it's going only 180 degrees it's a weather radar this is a transport aircraft they don't have to hit any targets or drop any passengers somewhere they are basically going to scan the weather ahead of them so therefore it has to move 100 degrees and if you if you don't have the cover you know what will happen so just to cover it up you have this red dome hence the material in the red dome has to be radar transparent so one of the first modifications that was done by us in India was to when we worked on the Dornier 2-2 aircraft in Kanpur was to build the red dome in India so very expensive red dome used to come from Germany so our small composite laboratory was set up red dome is a non load carrying body except for the loads which come in the front okay it does have aerodynamic loading but it's not impact loaders so we were able to do it and we were able to save a huge amount of foreign exchange instead of buying it from the Germans every time now we make our own red dome and after that we began supplying red dome to other countries and other places also okay these are the stabilizers stabilizers basically are moving surfaces either partially moving or fully moving on the rear of the aircraft which allows it for the longitudinal balance this is the longitudinal axis so to avoid uncontrolled pitch we have stabilizers so now let's see also a small film on trimable stabilizers you can see here you can actually adjust the whole surface to provide the required moment so this is not moving in the air during flight during flight only the rear portion moves this is adjustment of the whole thing on the ground before the flight adjust and lock so that you get a constant moment to balance it