Small, low cost, expendable turbojet engine. 2: Performance characteristics

A small experimental axial-flow turbojet engine was tested at sea level static conditions and over a range of simulated flight conditions to evaluate its performance as well as to demonstrate the feasibility of low-cost concepts utilized in its design. Testing was conducted at engine speeds as high as 37,000 rpm and at turbine inlet temperatures as high as 1,272 K. For maximum speed the engine produced a net thrust of 3,118 newtons at sea level static operation and 2,318 newtons at its cruise condition of M0 = 0.8 and 6,096 meters. Data obtained over a range of inlet Reynolds number indexes for nominal M0 of 0.38 revealed similar effects or trends on compressor characteristics of those previously established for much larger engines

Lightweight, self-evacuated insulation panels

Multilayer insulation of prefabricated panels is developed for cryogenic storage tanks. System utilizes panels of aluminized Mylar separated by sheets of low conductivity polyurethane foam. Panels are self-evacuated by cryopumping of gaseous carbon dioxide at time of use

Small, low-cost, expendable turbojet engine. 1: Design, fabrication, and preliminary testing

A small experimental axial-flow turbojet engine in the 2,669-Newton (600-lbf) thrust class was designed, fabricated, and tested to demonstrate the feasibility of several low-cost concepts. Design simplicity was stressed in order to reduce the number of components and machining operations. Four engines were built and tested for a total of 157 hours. Engine testing was conducted at both sea-level static and simulated flight conditions for engine speeds as high as 38,000 rpm and turbine-inlet temperatures as high as 1,255 K (1,800 F)

Minimizing Induced Drag with Weight Distribution, Lift Distribution, Wingspan, and Wing-Structure Weight

Because the wing-structure weight required to support the critical wing section bending moments is a function of wingspan, net weight, weight distribution, and lift distribution, there exists an optimum wingspan and wing-structure weight are presented for rectangular wings with four different sets of design constraints. These design constraints are fixed lift distribution and net weight combined with 1) fixed maximum stress and wing loading, 2) fixed maximum deflection and wing loading, 3) fixed maximum stress and stall speed and 4) fixed maximum deflection and stall speed. For each of these analytic solutions, the optimum wing-structure weight is found to depend only on the net weight, independent of the arbitrary fixed lift distribution. Analytic solutions for optimum weight and lift distributions are also presented for the same four sets of design constraints. Depending on the design constraints, the optimum lift distribution can differ significantly from the elliptic lift distribution. Solutions for two example wing designs are presented, which demonstrate how the induced drag varies with lift distribution, wingspan, and wing-structure weight in the design space near the optimum solution. Although the analytic solutions presented here are restricted to rectangular wings, these solutions provide excellent test cases for verifying numerical algorithms used for more general multidisciplinary analysis and optimization