Sage Bhardwaj is known for his Book yantra sarwas- This book is all about Vehicals, A movie by ayusmaan Khurana and mithun chakaraborti also made, where inspired by Rishi Bhardwaj book they make a aeroplane, which uses mercury as fuel. The same plane is used by Ravana known as Pushpak Vimana . Two Scientific facts need to be logged here: If you open your mouth and blow the air it feels hot but when the mouth opening is reduced same air feels colder. In Ramayana Hanuman enters in to sursa mouth, he ask her to increase size of mouth when sehe opens her mouth, Hanuman immediatly gets smaller and comes out of her mouth. hanuman is Pawan Putra, You try open your mouth big and big, you will feel you took lots of air but the moment you close your mouth the air comes Automaticaly from your nose,  Which Clearly  shows a Living body can not hold Air intentally. Also When hanuman goes to lanka , He burnt lankas. Just remember the Black smith Kiln for melting the metals they use High Pressriesed air and Normal fire with Pressurised air can destroy or melt Iron , which is symbol of Shani dev.  hanuman beaten shani dev,,,,,is just that Hanuman is Holding the Gada, Gada is a Hammer. And He is Vasu Putra means he knows all Properties of Air, and Water. Steam itself is Water +Heat. Black Smiths works on All metals. They can melt Iron and other materials. Ravan was a Learned Person of all Engineerings and Bio-Technolgy. All Pilars of Lanka made up of Iron. Hanuman just Produced the Current , of High Frequency.. Producing eddy Currents.

  As the Lanka was made up of Gold which is good conductor of electricity and heat So a small continuos current can make it melt. Also sea water can be used to make batteries?? Pushpak Viman : As the desighn using Mirrors and lenses, A difference in Air Pressure can be generated , Proper control of Heat energy , making Surfaces Hot and Cold can surely Thermo Dynamics is very Important subject. Even in space  Only Electricity and Heat are present. Going to space need thermo-dynamic system. Yantra Sarwas also explains Various Organic oils and Expansion Material, Rubber is One, Big Ballons can be inflated. Astra may derive- Astro Logy, Nomy,