UK and U.S. collaborate on the Centaur

The Warrior Centaur is a UK/U.S. funded project.

Designing and developing totally new aircraft is invariably a daunting process even for large and established aerospace organizations. For small companies, the challenge can be enormous, and when that new aircraft design is an amphibian making extensive use of composite materials, the likelihood of it ever becoming a reality may seem remote, however good the concept may be. But the Warrior Centaur amphibious light aircraft project, first revealed by Aerospace Engineering in 1998, has matured to become a UK/U.S. program with funding from the British government's Department of Trade and Industry (DTI) and from the Maine Technology Institute (MTI) in the U.S., to build a prototype for flight demonstration. The DTI is funding $640,000 under its Smart Exceptional Award program, only 10 of which are nominated each year. The MTI award, also highly competitive, is for $500,000. Private investors have committed more than $2.85 million in cash and services. The project has also benefited from the Handley-Page award of the Royal Aeronautical Society (RAeS).

Warrior says that a successful test program of the six-seat amphibian seaplane has been carried out using dynamically accurate fifth-scale models, and the company is now confirming the aircraft's detailed design using CATIA software. Warrior has also placed its first contracts for fuselage and wing tooling. The fuselage, wing, and other structural components are being built by Maine Composites, Inc. of Richmond, ME, and will be shipped to the UK during final assembly by Warrior at the certification facilities of CMC Ltd. Maiden flight of the Centaur is slated to take place in the UK in the first quarter of 2003.

The Centaur, powered by a single, 300-hp Lycoming IO-540 engine (with a 350-hp TIO-540 as an option), is said by Warrior to incorporate "a totally new approach to seaplane hull design and on-water handling." Its hull geometry has been derived from the designer's experience in the world of multi-hull racing yachts. "This (design) enables the aircraft to operate with much lower engine power than other seaplanes and to do so in up to 80% rougher water," said James Labouchere, Managing Director of Warrior and the Centaur's creator. Its boat-handling capability, aided by a folding wing, enables the aircraft to maneuver on water similar to a 40-ft boat, accessing berthing facilities that are denied to most other seaplanes. Labouchere explains: "Its all-composite structure means that it can operate on salt water without fear of corrosion, unlike conventional aluminum seaplanes."

Labouchere believes there has long been a requirement for a modern amphibious seaplane of the Centaur type with flexible load carrying capability and reduced seat/mile costs. "Tests of old and new hulls and free-flying dynamically representative reduced-scale models have enabled fast and radical development of both hull and structural configurations," he said. "This (development) has included testing in extreme conditions and circumstances substantially beyond the edge of the anticipated flight envelope. Testing has proven that these hull concepts now utilized in new fast ferries and offshore multi-hull yachts are applicable to seaplanes."

The low hydrodynamic drag and low structural weight of the Centaur's new hull and high-lift configuration has brought many benefits, said Labouchere. "These include comfortable operation in common coastal wave conditions; the ability to reach places normally accessed by boats; greater competitiveness with respect to useful load, payload-range, and cost-per-seat-mile; safety; ease of operation; and imperviousness to salt. "

Preliminary development activities for the Centaur have been based on a collaborative program between Warrior and CMC that was funded by the UK DTI Aerospace Division. Warrior is now working toward JAR 21 approval for design and manufacture to FAR Part 23 and JAR 23 standards.

The Centaur features folding wings.

Maine Composites is currently equipping a new facility for airframe development and manufacture of the Centaur. The facility is being prepared in accordance with FAA/CAA manufacturing requirements, said Labouchere.

The aircraft's primary structure is being constructed of graphite and glass fiber. "Bow, sponsons, and planing surfaces suit minor repairs in the field but are detachable for repair by component replacement," said Labouchere. "Sills and walkways are reinforced."

Warrior will be running both demonstrator and certification programs in parallel. The full-size demonstrator will be used to aid the marketing of the Centaur. All other airframes will be built from production tooling at the completion of design and testing. This development method is considered by the company to be the surest and least expensive, and will enable fluent production prior to certification and thus a quick ramp-up to series production. Options for the aircraft include hydraulic wing fold and a 10-hp water-jet thruster for low-speed maneuvering.

Initially, aircraft for the North American market will be assembled at Maine Composites. The European and Asian/African markets will be assembled at Warrior's facilities in Salisbury, UK. Warrior expects the first 10 production aircraft to be delivered on the day of certification. In the subsequent first full year of production, 68 aircraft are expected to be deliverable, 172 the following year, ramping up to 298 per year.

"This critical activity must be accomplished by effective warranties on distribution of parts and the availability of repair consultants and facilities," said Labouchere. "Much has been done in the design of the Centaur in using a spaceframe structure so those panels likely to be damaged can be replaced or repaired 'in the field.' Market support is also aided by a fitting out policy that uses state-of-the-art systems identical to those used by popular similar landplanes."

- Stuart Birch

T-50 enters static load testing

The T-50 Golden Eagle has begun static load testing at the Korean Aerospace Research Institute facility in Daejon, Republic of Korea.

Korea Aerospace Industries (KAI) and Lockheed Martin have begun static load testing of the T-50 Golden Eagle advanced jet trainer in preparation for the first flight test scheduled for later in the year. Results from the static testing will be used to certify the flight worthiness of the aircraft and validate the aircraft's structural computer model used in the development of the airframe.

The static test aircraft was completed in October 2001, and extensive instrumentation has been installed and checked out. The first test case will involve 77 load applications, 66 deflection measurements, and approximately 2300 strain measurements.

The T-50 is designed to have the maneuverability, endurance, and technology to prepare future pilots for current and next-generation fighters such as the F-16, F-22, and Joint Strike Fighter. These same characteristics will enable the fighter to serve as a light-combat aircraft in many air forces.

The lead-in fighter trainer/light-combat version of the Golden Eagle is designated the A-50. The main differences between this version and the noncombat version (T-50) are the addition of an armament system and fire control radar. The T-50 structure has been designed to accommodate the loads requirements of the A-50, including combat maneuvers with stores.

The T-50/A-50 advanced-technology features include relaxed static stability, digital fly-by-wire flight control, side-stick controller, selectable flight control performance, triple-redundant electrical system, onboard oxygen generation system, modern cockpit (head-up display, color multifunction displays, hands-on-stick, and throttle), and integrated armament/fire control avionics (A-50 only).

Designed for load limits of +8g and -3g, the T-50 was tested at 100% limit-load on January 6. Four additional limit-load conditions were tested later in January and February in support of the dynamic load analysis required prior to first flight.

Forty ultimate load conditions (150% of the design limit load) are planned for the program. Each load condition test is expected to take approximately two weeks to complete, with final static testing targeted for completion in August 2003.

A separate ground test aircraft being built for durability (fatigue) testing will be completed this spring, with durability testing scheduled to begin in the summer and continue through June 2004.

- Frank Bokulich