 And then we have this disaster which is a very famous disaster called as the Hindenburg disaster. So with the Hindenburg disaster the intercontinental airship travel became completely unacceptable. So we should spend some time understanding what happened in Hindenburg. So Hindenburg was a very ambitious airship. It was the world's largest airship ever built and launched in 1936. And you can see that it has a massive engine from Mercedes-Benz giving large amount of thrust. 16 bags of helium were installed in it. It could travel more than 10,000 miles nonstop, a distance or an endurance which is very difficult to achieve even in today's aircraft. I do not mean there are no aircraft which can do this. There are aircraft which can travel 16,000 kilometers. All the long-range aircraft like 777-300 or 767, they can travel this distance today. But this is 1936 and they would remain in air for 5 or 6 days. So it will be a one-week flight and you would be cruising across Atlantic in around 50 to 60 hours. They did 10 and a half round trips between Germany and USA with no issue, with no incident. So people think airships are unsafe. They forget the record of having travelled so many thousand miles without any incident. But yes, this accident took place when this aircraft was about to land at Lekhorst New Jersey in US. There are many interesting theories about Hindenburg and why it caught fire, what is the cause of the crash. So because it is a very well talked on subject, so the latest information that we have after a series of investigations is that the Hindenburg was coated with some kind of a doping material which was full of aluminum oxide, AL2O3 and AL2O3 you know is what bombs are made of. It is a highly explosive material. So to dope the fabric at that time, they used AL2O3, it gives a nice aluminized finish to the surface and there was some kind of lightning strike or a static electricity generated onto the airship because of which there was a spark, there might be some kind of a leak because of which it caught fire. Then you know it was almost coming into land and all the reports say that you know 35 people died in this crash which consisted of 22 crew and 13 passengers but what does not get recorded is that 62 people actually survived this incident. So in an accident if 32 people die that makes more news than 62 people survived. Let us look at this airship, how it was, how it was flying. Talking about rigid airships is a terrible accident of the Hindenburg. After a successful career as a passenger and cargo ship the Hindenburg caught fire at Lakers. Miraculously 62 out of 97 came out of that inferno alive. It sounded the death knell of dirigibles in the United States. It is without me in this war which derives from the landfasm of the North Sea. The history of rigid airships is a story full of excitement and adventure. The Hindenburg made 10 transatlantic round trips between Frankfurt and Lakers plus several round trips to South America. The Hindenburg flew over 200,000 miles, carried 3,000 passengers and 41,000 pounds of mail and freight. Besides passengers and mail the ship carried a great variety of cargo ranging from canaries to automobiles, airplanes and heavy machinery. We never missed a schedule flight and never turned back. Accommodations included freshly prepared meals, state rooms, shower, promenades, writing rooms, lounge with grand piano, smoking room and bar. The Germans have demonstrated that the commercial rigid airship was an extremely comfortable method of travel. Far faster than the steamship, regular in schedules and reasonable in price. But even more important, the rigid airship was safe. Even with hydrogen, the safety record of commercial rigid airships surpasses that of any other form of transportation. Noiseless and vibrationless, the big airship provided the acknowledged maximum comfort in oceanic travel. Now let us see what happened on that day. So this is a time when the video recording equipment, news reporting using video is also picking up and during that time there was this accident which was recorded live and relayed on many channels all over the world. So this is one of the first disaster videos which became public. It is there in every encyclopedia, it is there in every disaster compilation and because of this many people feel oh airships equal to disaster, airships equal to fire, airships catch fire. So we have to look at the things very critically. Yes, they do have their limitations and yes this airship did catch fire, there you go. This is the indication of the first, now what is being done here is water is being blasted to reduce the weight of the airship. What you saw was water being thrown down. So to reduce the weight of the airship for it to be trimmed and brought down for landing, water blast was used, we will study about this in great detail in this course. Yeah, that fellow actually jumped down. This is not a disaster, this is a video of a normal operation of Hindenburg. No, no, no, that person had a problem, I am not talking about that person only. I am just saying that this is not the disaster video of Hindenburg. This is showing Hindenburg in other flights. You can observe that we are having the requirement for so many people. There are passengers who are sitting inside the airship. When you get off, you have to be careful because the airship can move slightly with the wind. This is the captain of the airship and now the problem start. As it is approaching the mooring mast, notice the sky is cloudy. It is there is lot of static in the sky. Now in your school you must have learnt about properties of hydrogen and one of the properties of hydrogen is it burns with a colorless flame. But these are not colorless flames, these are orange colored flames. So the color that you see is basically that of the fabric which is burning. Yes, there is hydrogen also burning but the start of the fire was an orangeish flame which was from the fabric. So the conclusion that has been drawn in the recent study is that the cause of fire was not use of hydrogen. The presence of hydrogen has accentuated the fire. The cause of the accident was ignition of the surface of the envelope which was coated with AL2O3 and then of course once you have hydrogen and flame and oxygen there has to be combustion that you cannot take it away. So it was literally the end of use of airships for passenger transportation and as time is progressing aircraft are becoming more and more capable, more and more robust, larger in range and all the shortcomings of aircraft unreliable, short range, less capacity, they are slowly and slowly being addressed. So after this complete hibernation, people said we should not use airships because they catch fire. If we had helium in this airship it would not have caught fire. So with the accident of Zeppelin, with the accident of R101, the Germans decided, furor decided we will not use airships in Germany anymore and he cancelled the Zeppelin project because it was bringing a bad name to Germany. This is the time when the Second World War is now picking up.