Fly The Wave - Warrior (Aero-Marine) Ltd.

Warrior Seaplane

CENTAUR CONCEPT: DESIGN

Encouragement

In the late 1950's, extraordinary things were happening. Conventional seaplane hull shapes were getting slimmer and losing weight. Both aerodynamic and hydrodynamic performances were on their way up fast, as were load capacities, speeds and payload-ranges. Glenn Martin (subsequently Lockheed Martin) had sights on:

"… a significantly superior hydrodynamic solution to many current problems… greatly reduced conflict between hydrodynamic, aerodynamic and structural requirements … and vastly expanded potentialities of water based aircraft in general."

Yet these shapes did not reach the General Aviation market! With the use of slender hulls derived from the recent developments in the fast-ferry and racing-yacht industries, non-corrosive materials and a practical configuration, much better can be done.

The concept

A wide range of considerations have influenced the layout of the Centaur concept including cabin volume, access, low take-off speed and boat handling duties. The Centaur concept's layout has been found to accommodate an efficient structural and aerodynamic package with attractive water and in-flight handling qualities.

Performance from the new hull

Warrior's new Patented hull features no transverse step and no forebody chines. It is a new conceptual approach which re-writes conventional texts on seaplane design. This hull accelerates to about seventy percent of take-off speed in displacement mode by which time the water is satisfactorily "hard" and aerodynamic lift takes more than half the weight of the aeroplane off the water. The Centaur encounters no drag hump. This leaves much more thrust available than conventional seaplanes for getting more useful load airborne in a respectable distance.

This useful load advantage is further increased by the reduced structural content and weight in the hull, having typically half the beam and surface area of conventional seaplane hulls (floatplanes or flying boats).

Wave handling from the new hull


The fine bow results in little rotation. Any rotation is heavily dampened by new features on the planing surface. Because of the narrow beam, any remaining rotation results in less rise, wave dispersion, spray and wasted energy. It is thus unconventionally stable, docile and efficient in rough water. The Centaur can handle short steep waves typically twice the height tolerated by equivalent seaplanes.

Composites designed for resilience and repair

Composite airframes must necessarily be designed to damage tolerant criteria and can readily be certified for high fatigue lives. With the primary structure largely inset from a secondary shell, the Centaur will tolerate the maximum amount of abuse without compromising the integrity of the aeroplane. This feature also aids repair without specialist facilities.

Repairs are aided by the use of remarkable vinylester-epoxy laminating resins which have established and proven themselves in both marine and aviation industries. They are in effect impervious to bacteria, acidic content in fresh-water and salt-water. They have good impact and shock-absorption properties. Even with minor damage, their resistance to fatigue and water ingress is high.

Aerodynamics for lift and efficiency

Warrior has adopted a conservative approach to wing and tail aerodynamics including choice of airfoil sections to assure the safest possible operation.

The Centaur's low stub-wing uses ground-effect aerodynamics to aid low take-off speed. This is helped by a continuous flap through the wing center-section which provides much lift in the propeller slip-stream. These features minimize power-on flying speed and get the Centaur out of the water early.

The flap and wings create down-wash on the tail. This down-wash substantially balances the pitching effects of changes in power and flap setting. Combined with slow landing speeds, these make the Centaur concept a safe and attractive aircraft to fly.

Computational Fluid Dynamics (CFD)

Modern design methods using Computational Fluid Dynamics (CFD)

Wing-fold capability

Using engineering content near identical to the undercarriage, the outer wing panels can be released and folded back to within the beam of the sponsons, so that the Centaur can be berthed or tied up against the side of a dock or ship, or in marinas. In preparing for flight, as they rotate forward to the locked position, a central stub spar mates with the spar in the wing panel, thus completely removing bending forces from the hinge. The aircraft cannot be flown unless locking is successful and the wings cannot be unlocked unless taxiing at low speed on the surface.

Design fluency

The Centaur concept is designed using CATIA 5 (sponsored by INCAT of the UK), which is generally understood to be the most advanced computer aided design software used in aerospace and automotive industries. It enables the different design disciplines to be integrated efficiently right through the Certification and production programme.