 Okay, so we do a tutorial today in which we look at both the lectures that we have studied so far. First we start with this tutorial on aircraft component nomenclature. This tutorial is based on a recent visit that has been conducted by us. So what are you going to do here is we are going to explore some interesting components but these components are not from the fixed wing aircraft about which we spoke last time but from four interesting helicopters. So during our recent visit to Juhu aerodrome which took place on 15th of June we visited this aerodrome okay. So this is the proof that we actually went there and we went to two companies. One is Raymond international they had two helicopters on display at that time these are being maintained and we also had a look at the Tata power company where they also had another two helicopters. So the major discussion that will take place in this tutorial is about these four helicopters and then in the end I will show you another interesting aircraft. So let us have a look at this picture and see if you can find some familiar components okay. So for instance what do you think are these yes how can you say it is a pitot tube so anything in the front of the aircraft is a pitot tube it could also be a pitot static tube is there a difference between a pitot tube and a pitot static tube so do not worry we will study about it okay okay right. Then what about the thing on the bottom yes that is a red dome correct that is a red dome so there are hints so part one we also ask them to open it and show it to us so you can see this is a scanning radar so yes it is a red dome and therefore the material that was used to make that part is not metallic it is a glass fiber composite if I remember correctly what are those lines those black lines two lines are there because we are pointing out at them but on the red dome there are these lines painted yes but notice they start from the front and end before the end there is no continuity to the structure the one on the left and the right there is no continuity they start from the front of the red dome and they end before the red dome ends correct so do not jump to conclusions and do not give a lot of wind to your imagination it is a good attempt but that is not the reason that is not what it is okay anything else yes for visual indication so that no one steps or hits it by mistake that is what it is it is just a visual indication to prevent bumping that is why it is a weak structure it does not have any backing part inside so even if somebody kicks it there can be a damage so it is just an indication I do not think there is any technical significance to that part okay right let us see what is the second part that is a pitot tube cover now we know it is a pitot tube because we saw static ports mounted on the side of the fuselage so it is a cover alright there are two parts which have been sketched okay now this is a this is a bonus question I must tell you one thing that even I had no idea what these parts are with so many years of experience in aviation I had no idea so hang on a minute experience people will come to you last can the students try to guess what are these two jutting parts one below and one above the helicopter one of them is on the below on the bottom side the other one is on the side top side so what could these parts be yes no they look like antennae that is what I thought but they are not antennae yes they are no no no it is a good guess but why would you have one below one above and let me tell you both of them are functionally identical so how would these two parts give you vertical speed no they are just metallic pieces yes no no they are not lights lights are mounted in a much bigger they are much larger yeah above the helicopter you want to have a tail skid look look look look listen both the parts are functionally identical therefore if one is a skid the other cannot be a skid and how can you have a skid on top of the helicopter think before you answer think yes above the door and below the below the fuselage to open the door and why would it be such a horrible shape if it is a door it will be a handle yeah he is coming near to the answer can you now guess that is right wire strike protection system when helicopters fly at low altitudes they may encounter these kind of wires so those two devices above and below helicopters are basically going to protect the helicopter from getting entangled in these wires so this is a very interesting component wire strike protection system all right okay what is this the thing on the bottom which is curved so is it an antenna is it a pitot tube or is it a towing hook to move the helicopter back and forth what do you think the answer is now the above so what is it yeah tail drain pipe that is a good guess drain pipe for draining out excess water but look it is coming from the light so it cannot have any water elements near an electrical component intentionally by this way you will short the light so not a drain pipe I will add that fourth point there what do you think look at the location look at the shape is not pointing forward the helicopter is actually pointing towards the left in the figure on the left yeah that is what people think it is an electric it is not it is just a tail skid it is just a tail skid a device which will protect the helicopter rear boom from hitting the ground now this is a very special helicopter I also wanted to observe the mounting of the horizontal tail you can see a vertical tail with a red strip you can also see a horizontal tail and this horizontal tail this horizontal tail basically is mounted in a particular fashion about that we will come again later okay what do you think are these parts the one on the left it says do not hold looks like a handle but it is a do not hold and the one on the right is a simple giveaway anyone can guess what these parts are both of them are antennae right now here we see inside the cockpit there is a stick which seems to be bent it seems to be having a curvature so what is this stick and why is it bent yes it can moves in four ways that is why it is bent so as to give clearance to the driver's leg and see yeah pilots please sorry pilots okay but pilot is also a driver anyway it is not a not a problem you are not technically wrong but we call it we call the pilot the driver of a aircraft as a pilot so yes this is to clear the knees of the pilot because there is a situation of very cramped operation in the helicopter and this is the helicopter yolk which is used for giving the command except one on the bottom you can see on the right picture there is a shaft like thing on the bottom that is meant for the collective pitch I will talk about this when I talked about helicopters okay this is a very interesting component and we were given a huge description about this component and its cost implication etc. I must give you some hints this component is recommended only for India or mainly for India by the helicopter company it was not there in the original design when the aircraft was sold to countries like India then they have recommended installation of this particular system it's very expensive what is it and what is the purpose yes Mike Mike please is it a radiator what do you mean by a radiator the temperature under the hood can get quite toasty so it's there to decrease it no it's nothing to do with heat transfer no it's not a radiator it's not a radiator anybody else there is a very fancy name for it and it is pretty expensive this is not nothing but anybody else want to guess quickly this is basically a dust cover okay but it's a very high fidelity dust cover it has got some active chemical inside which doesn't allow the dust to go in they observed that when helicopters are flown in countries like India because of the tropical climate and the presence of dust and other particles the engine was sucking a lot of undesirable elements and when you put a filter sometimes the filter gets clogged because the particle just stick so they came up with a very interesting design where there is some kind of a fluid which is put in this part and it repels the dust so it's a very expensive item and it has been recommended it took about a couple of months to get it retrofitted in the helicopter alright this is the photograph of the tail rotor you can see that one rotor which is facing the camera or I should say cross sectional of the rotor is visible in the camera and then there are two of them which are you know bending down like this so why are they bending down are they supposed to produce lift are they supposed to be horizontal why are these rotors bending downwards yes just a minute no one here can guess why are they bending down yes sir they are bent they are bent down due to itself weight and they are intentionally bent down so that in the case of producing producing lift they must not okay so they are bending down just because of their own self-weight that's all it is just because of the self-weight and when they start spinning they will generate lift force and that will actually create a lot of stress so this particular weight actually will act as a relief it will be in the direction opposite to the direction in which the load is coming what do you see at the edge of the helicopter there is a small metallic strip with two nuts very clearly visible and only in the front part only in the front half what is that and why is it there what do you think just a protection so the most common problem in helicopters is when they fly in small areas the tail rotor start hitting it's not that if something hits the rotor it will not break but if it just scrapes the rotor at least this thing will give some protection okay this also may be an excess providing access to some internal areas of the helicopter rotor for maybe maintenance purposes observation oiling etc. I don't know but my guess is that this is just a protection plate yes why this metal yes because helicopter rotor don't turn in the opposite direction they turn only in one direction so if something is scraping the front part will be hitting it first okay that's why they put it only on the front half okay now this figure is not a question this is just to give you an idea about how complex the tail rotor of the helicopter normally is and there is a reason why I am showing it see notice there are two links here one on the top one on the bottom okay these allow this whole assembly to move forward and backward then we have one link here and one link below that is meant for changing the angle of the rotors together okay then you can see there is something here and there is something here what are these what do you think are these and there is a kind of an angle here which allows you so what is that yes yes coupling that's a coupling so because it's a rotating part now from the main helicopter rotor shaft there is a shaft coming and then it turns 90 degrees in this case and then it couples to the shaft on the so it's a very complicated system so if possible we should get rid of this complicated system if possible if it is visible but why do we need a tail rotor in a helicopter why is a tail rotor essential in the helicopter let's have some new people anybody would like to answer yeah angular momentum angular momentum can you explain like the main rotor start rotating the helicopter tends to counter rotate so so it is basically meant to counter the auto rotation of the helicopter body when the main rotor rotates so you put a rotor on the back give a force to counter that so the moment created by the tail rotor is just enough to overcome unless you want to intentionally move to the left or right okay so that's why the rpm of the main rotor and the tail rotor I mean the rotor have to be coupled because as you increase the lift or the rpm you have to also have a corresponding change so it is complicated and this is the most common reason for mechanical faults in helicopters it's a nightmare for maintenance so we'll see how people have attempted to modify this I also was very you know intrigued to see these kind of cuts so you see the side view of another helicopter from the Raymond's hangar you find that the tail rotor you know if there is one member jutting out here you can see it here also prominently okay and then you see this very interesting shape on the tips similarly I took a photograph not me one student who went with me took a photograph of the tip of the main rotor so these are required for manipulating the tips because the tips have tipped vertices as we will study and providing such shapes helps in reducing now this is the photograph of the horizontal stabilizer of one of the helicopters and I observed that the top is flat and the bottom is curved so I told you made a mistake in mounting this so it should be upside down right because we never see a fault flying like this so what is the reason is it intentional what do you think is it a mistake or is it intentional what do you think it is intentional nobody makes such mistakes in aircraft design okay that means what will happen if you have tail upside down like this what is the result of this kind of a mounting downward force tails won't produce lift tails produce a force for balancing the aircraft so there will be a lift by nature is considered to be upwards so if something is not upwards we do not call it lift generally okay it doesn't lift so it's pushing down so from the point of view of balance of the helicopter you needed a downward acting force always or mostly and hence they have mounted it upside down the same thing you also see in aircraft when I saw the aircraft do to it for the first time in the hangar I also was surprised I found the tail to be mounted upside down and that's when I remembered the course of stability and control where I was taught that generally the tail carries a downward force so the one good way of doing that is to mount it such that it gives you downward force this is another helicopter this is the helicopter in the Tata international hangar incidentally this helicopter is personally flown by Mr. Ratan Tata he flies it himself now I don't see a tail rotor here so has it gone for maintenance or is it not there intentionally what do you think where is the tail rotor in this helicopter both sides are only fixed vertical tails and there is also a very small horizontal tail and also you can see a small tails kid the white one but the rotor is missing so what is the reason yes no it doesn't have a twin rotor you very right if you have two rotors which are counter rotating like in the Kamov helicopters with the Indian Air Force yes you would not require a tail rotor but I think if you have seen some earlier pictures I don't know whether we have some earlier pictures of this helicopter maybe I have to just search but believe me it has only one main rotor so it doesn't have two rotors controlled by jet which the jet from the exhaust of the engine no no that is not the thing this helicopter is very interesting yes the exhaust gas from the engine yeah that is the exhaust of the engine correct yes at the tail that means somewhere here so you mean to say that but I see the exhaust is here there might be okay there might be but no there is this is not an exhaust hole so that's that's not the that's not the reason okay this this helicopter is called as a no tar which means no tail rotor that is a selling point of this helicopter so what they do here is they use an effect called as a kawanda effect about which we will study when I come to that portion I am going to elaborate to you on that so yes there is a small duct there is a small duct and a small outing on the bottom okay and this particular this particular you can say assembly rotates also but we don't have the engine exhaust from there so we don't use that for I'll explain this to you when I come down to the kawanda effect okay after this we went to the Bombay flying club which is located in the same Juhu airport and this is a very historic aircraft behind us this is considered to be Asia's oldest aircraft which can still be flown it was fabricated in 1940s brought to India 1951 it came to Bombay flying club in 1955 and they have maintained it from that point onwards till today in a very perfect condition so look at this picture can you think this aircraft was 1940 aircraft 65 years of service it was also flown by J.R.D. Darpa himself so such a historic aircraft is available in Bombay flying club and we were very fortunate that on that particular day we were able to go and have a look at this particular helicopter this gentleman on the white shirt to my left is the Mr. A.K.A. Ajay Kumar Bahadur who is the chief engineer of Bombay flying club and he was our he was our host that day for this particular trip so first we went to the two helicopter companies and then we went to this place and then they also gave us a very nice lunch after which we came back alright so that's it about the first capsule