3329. WAMI – a Menu-Driven Computer Program for the Estimation of Weight and Moment of Inertia of Earth-to-Orbit Transports

Paper

Abstract

A program, entitled Weights, Areas, and Mass Properties (or WAMI) is centered around an array of menus that contain constants that can be used in various mass estimating relationships for the ultimate purpose of obtaining the mass properties of Earth-to-Orbit Transports. The current Shuttle mass property data was relied upon heavily for baseline equation constant values from which other options were derived.
Characterization of the mass properties of any Earth-to-Orbit transport is complicated by the enormous amount of detail that is needed to support the end result ? the end result principally being weights and centers of gravity for the various stages of any one mission. In the WAMI program, menus are provided containing a number of options for constants for each subsystem. Usually, one of the menu options is based on the current Shuttle. Additional values are based on various technological and configurational assumptions.
The menu system to obtain mass properties facilitates both the work of the user and the ability of the recipient in understanding the results. In using Shuttle data for the calculation of the basic constants, the fidelity of the mass estimating equations is enhanced. It is not practical, at least at the conceptual level, to identify all of the non-optimum weights that should be assigned to a given subsystem. For example, analytic solutions for structure are still needed to identify innovative configurations and to demonstrate the utility of new materials. However, the so-called ?stress? wing is typically only about one half the weight of the ?real? wing. By utilizing Shuttle mass properties as a base, data for realistic values for non-optimums and the all-up structure are obtained.