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Contributed paper U-99 uninhabited tactical aircraft preliminary structural design
Howard Smith

1. Introduction
As we enter the new millennium, the preferred means of waging war has evolved out of all recognition compared with that of the last 30 years. Military might must be powerful yet precise enough to prevent civilian casualties and still be mobile and fast. With politicians and thegeneral public having a dominating influence over the decisions of commanders in the field, casualties to friendly forces must be eliminated. It is clear that air power is the first and often only option that can meet these needs. Simultaneous with these ever-growing demands for higher performance is an increasing pressure to make significant reductions in costs. Maintaining an overwhelming dominanceof the air has always been expensive and so fulfilling all these requirements simultaneously will push aircraft designers to explore radically new opportunities. 1.1 The uninhabited tactical aircraft concept One novel concept appears to offer a solution to all these challenges. The uninhabited tactical aircraft (UTA) or unmanned combat air vehicle (UCAV) is seen as a new class of aircraft that iscomplementary to the existing or planned manned fleet. The ability of this aircraft to effectively perform strike and suppression of enemy air defences (SEAD) missions, while achieving dramatically low life cycle costs (LCC), has made it a serious contender for the UK requirement for the Tornado replacement future offensive air system (FOAS) or possibly part of such a system. Similarly, theAmerican Department of Defense currently sees it as an important element in its future armoury. While such an advanced weapon system may seem like science fiction, it is envisaged that the concept could be operational soon after 2010. The UK defence industry is highly secretive about such developments; however, it is known that one of a number of options being considered for FOAS is a UTA. It is alsoknown that the joint USAF/DARPA UCAV advanced technology demonstrator (ATD) programme intends to have a UCAV flying by 2002. This is intended to lead to an aircraft with a unit cost of one-third of the joint strike fighter (JSF) and an operations and support (O&S) cost reduction of 50-80 per cent. 31

The author Howard Smith is Senior Lecturer, Aerospace Design Group, College of Aeronautics,Cranfield University, Cranfield, UK. Keywords Military, Aircraft industry, Design, Unmanned combat air vehicle Abstract Describes preliminary structural design work on a notional uninhabited tactical aircraft (UTA), carried out at Cranfield University. UTAs are seen as an important future element of military fleets. A notional baseline requirement was derived, leading to the evolution of a designsolution. The basic requirements for such a UTA are naturally highly classified but, although industry has been hesitant to comment, the baseline requirements and design solution developed herein are believed to be reasonable. Electronic access The current issue and full text archive of this journal is available at http://www.emerald-library.com/ft

Aircraft Engineering and Aerospace TechnologyVolume 73 . Number 1 . 2001 . pp. 31±55 # MCB University Press . ISSN 0002-2667

U-99 uninhabited tactical aircraft preliminary structural design

Howard Smith

Aircraft Engineering and Aerospace Technology Volume 73 . Number 1 . 2001 . 31±55

1.2 Derivation of requirement As the basic requirements for such a UTA are highly classified, no industrial contacts were prepared to supply specificdetails to work from. To make progress a notional baseline requirement was derived, and while industry has been hesitant to comment openly on the requirement, it is believed to be reasonable. Conceptual design work proceeded over a period of two years, assisted by two Aerospace Vehicle Design MSc postgraduate students (Antonio Texera da Costa and Mansour Bin Eid), during which time the baseline...