Hydrogen tube vehicle for supersonic transport: 3. Atmospheric merit

Hydrogen tube vehicle for supersonic transport: 4. Hydrogen propeller

“…as the propulsive efficiency for tandem disks in a tube; V can validly assume the value zero in (11), but V and V s cannot simultaneously be zero. By inspection, because h is a continuous function of V s and w, with V fixed, h converges to its maximum value of unity as V s / V and w ¼ 0.…”

“…Thus, the vehicle can be strongly supersonic outside while subsonic inside. For laminar flow over a flat plate, skin-friction drag varies inversely with the square root of the Reynolds number [11,12]. Assuming the same speed and same characteristic length [4,5], the Reynolds number for the hydrogen vehicle is half the number for the land vehicle but twice that of the body at altitude.…”

String Stability towards Leader thanks to Asymmetric Bidirectional Controller

“…Moreover, relying on drag to ensure a positive property is probably not the best control engineering solution, when modern transportation systems like the latest vacuum tube transit proposal (see e.g. [Miller (2012)]) try to minimize the drag for energy efficiency purposes.…”