Feasibility of Extremely Heavy Lift Hot Air Balloons and Airships

Abstract

State of the art airships and aerostats (air vehicles) use hydrogen and helium as lifting gases. Hydrogen is extremely flammable, while helium is rare and expensive. In the present work, feasibility of air vehicles using hot air, hot nitrogen, and/or hot mixture as lifting gases is demonstrated. Thermal power requirements for air vehicles using hot lifting gases are calculated. 1) It is shown that for extremely heavy aerial vehicles, whose gross takeoff mass exceeding 3,000 tons, required thermal power is proportional to 1/3 Mvehicle where Mvehicle is an air vehicle mass. 2) For lighter aerial vehicles, whose gross takeoff mass is below 100 tons, required thermal power is proportional to 2/3 Mvehicle . Specific thermal power requirement is low for extremely heavy vehicles and high for light vehicles (For 1000 ton gross takeoff weight, specific thermal power requirements are from is 41 W/ kg to 52 W/kg). 3) Using hot nitrogen and/or nitrogenhydrogen mixture decreases thermal power requirements by 10% to 24%.