 Now, coming to the future about what is being planned, so the future is going to be driven by solar power. So even in airships there have been attempts to go for use of solar regenerative fuel cells. This file, this is the paper which I am going to upload. This is the interesting paper 2003 by JAXA in Japan. So I am going to upload this on the Moodle page and there will be a special presentation on the stratospheric airships or high altitude airships. So at that time we will discuss this in more detail. Today we will just look at solar propulsion. So especially for airships which are designed to be operating for a very very long time 3 months, 6 months without any interference by the humans. Not for carrying passengers but for carrying communications payload. The suggestion is to use solar regenerative fuel cells SRFC. So how they work is that on board the airship there is a electrolysis unit which converts water into hydrogen and oxygen. Then this hydrogen is pumped into on board cylinders. Do you have any idea about the dimension of this airship? It is 360 meters in length, 1000 feet in length, so that is enough space on the bottom to store that much of water. Moreover the requirement of water is not very high because you are using rating it. You are creating hydrogen oxygen pumping it into bottles using hydrogen in the fuel cells generating power and recovering it and again reusing it. And there is a huge envelope available for solar array. So this is how they work during the daytime from something like 7 am when the sun starts generating some power that is here point number to 7 am to around 5 pm the solar power available is increasing. The peak is coming around noon and the power required by the airship is only this much these lines. So the difference in the power that is this minus this is used to store in the on board batteries and then the stored batteries provides power from this time when it is less than required till next morning. So in the night time the batteries are going to give the power. In the daytime the batteries are going to be charged. So this is a schematic diagram and you can see that water is electrolyzed into H2O2 which goes into fuel cells so in the night time there is power switching and the electrical engine is powered by the hydrogen fuel cells. During the daytime there are solar arrays which give solar power and then there is the daytime line it bypasses the system and provides power. So this is not a theoretical concept they have already made and tested the concept. So this is a for example a 1 kilowatt test bed which was made and tested by a Japanese more than 12 years ago. So it is done already but even now there is no satisfactory airship actually flying. Many countries are working on it including India and there are plans to bring it up. Okay we look at now thrust vectoring which is ability to manipulate the direction of the propulsion force in the direction that you would like to do. And here I would like to showcase to you two small videos. One video is thrust vectoring as an indoor airship which was done by an intern recently as part of his internship. So this is a very simple bandola for an indoor airship which will be mounted below the airship and on that there is a central rod with a servo motor so you can see that by controlling the direction of the remote the motor can do so well. So this is the okay then we also tested this system a similar system not the same system but a much better system than this. This is a very simplistic system. So you can see that a slightly bigger motor is being installed on a central star. This is a dandelion which comes below the airship and on the back is the airship envelope. The white one is the airship envelope. So this thrust vectoring is basically by you know tilting the whole engine because the entire motor was tilted up. One more example of tilt engine is what you already know. This is an example of tilting the engine. We have seen so many examples of this. Another example is tilting the slipstream. In this case the engine is untouched, it is fixed but the slipstream of the engine is deflected by a very intelligent use of connected vanes. Just like when you have these levers on the curtains you can use it to control the vanes. So the pilot basically operates a lever and with that lever these flat or slightly curved plates will deflect and they will deflect the slipstream which will give you the thrust vectoring. So what you are seeing here is the thrust vectoring onto a Russian airship called as AU-11. So this is the picture of the Russian airship. This is a single pilot airship and the pilot has this thrust vectoring lever through which the engine mounted behind the pilot gives you the thrust vectoring. So that is all I have today for the propulsion system.