Hello Guys, Please provide your opinions on the following Hypersonic Tunnel based transportation system? I am a Computer programmer and not some aerospace engineer, so kindness is appreciated :-) The primary problem with hypersonic(or supersonic) travel is that we have to remove several tonnes of air in front of the vehicle every second at hypersonic speeds by ramming our aircraft into it. This requires a lot of power and structural weight etc. My design tries to bypass this primary bottleneck. In my design a hypersonic rocket powered aircraft moves inside a tube of large diameter. The tube spans the entire path of the journey. This tube is filled with hydrogen(or some other gas) at low pressure to reduce drag. This tube is also lined with metallic foam from the inside to reduce the shockwave inside the tube(like a suppressor of gun). The vehicle inside this tube feels that it is traveling at very high altitude(hence very low drag) throughout the journey. This setup should solve almost all problems associated with high speed flight by a big margin. My design is roughly equivalent to the design discussed at http://dsc.discovery.com/convergence/engineering/transatlantictunnel/interactive/interactive.html [Broken] and . But there are two major differences. Firstly, I am using an aircraft and not a train and secondly, I don't have a vacuum inside the tube but some gas that provides good lift to drag ratio(possibly hydrogen, but there are other contenders) at hypersonic speeds. This setup avoids the huge construction and running costs of a maglev system and is safer as precise tolerances are not required. Basically, the system is tube with hydrogen in it which simulates upper atmosphere. I have done the patent search and haven't found anyone proposing it. Please let me know if someone else has explored this concept before.