3318. Weight Study of the Gemini : An Ultra-Heavy Lift Aircraft

Paper

Abstract

Vesper Design Concepts presents Gemini, an Ultra-Heavy Lift Aircraft in response to the 2002-2003 AIAA Team Undergraduate Aircraft Design Competition. This aircraft is required to carry ten M1A2 Abrams tanks over an unrefueled range of 5,000 n. mi. at 500 kts at an altitude of 25,000 ft. or more. As a conventional aircraft would require a wingspan in excess of 400 ft., Gemini utilizes an unconventional c?wing configuration to limit its span to 300 ft. Weight analysis of an aircraft of such unconventional size and configuration has required/resulted in some interesting weight optimization studies. Empirical methods were the main form of analysis used in creating an optimized weight buildup. Analytical methods were only used to contrast with the empirical ones. Initially, very simple methods based on historical trends and basic parameters were used. These led into more complicated empirical relationships focusing on specific aircraft weight groups. Three different methodologies taken from aircraft design texts, were used to define and optimize the Gemini. These methods, along with known aerodynamic quantities, allowed the wing and canard to be optimized for cruise. The placement of different weight groups on the aircraft allowed construction of its pitching moment equation. This in turn allowed the canard to be optimized for trimming the aircraft during takeoff. The landing gear weight was examined in more detail, as it had to be built to take some unusual conditions, like the 15-feet-per-second vertical descent rate. The structural weight was also examined in more detail, as the empirical estimations most likely did not account for a floor loading as high as Gemini?s.