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. Even if they had, with the help of revolutionary slender hulls derived from recent developments in the fast-ferry and racing-yacht industries, much better can now be achieved.
The concept
A wide range of considerations have influenced the layout of the Ocean seaplanes concept including cabin volume, access, low take-off speed and boat handling duties. The Ocean seaplanes 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 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 Ocean seaplanes encounter 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 pitching. Any pitching is heavily dampened by new features on the planing surface. Because of the narrow beam, any remaining pitching results in less rise, wave dispersion, spray and wasted energy. It is thus unconventionally stable, docile and efficient in rough water. The Ocean seaplanes 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 Ocean seaplanes 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 Ocean seaplane'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 Ocean seaplanes 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 Ocean seaplanes concept a safe and attractive aircraft to fly.
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 Ocean seaplanes 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 for the environment
The Ocean seaplanes are designed for positive environmental implications in operation, including;
- flying point-to-point to relieve demands on secondary and tertiary surface transports and their infrastructure.
- using common established dock and marina facilities.
- taking pressures off building new airfields to leave forest and agricultural land in place.
- fundamentally raising transport efficiencies among current seaplanes and helicopters.
The through-life carbon footprint will be minimised by long airframe lives and using both low-temperature cure resins in manufacture and carbon-fibre recycling at the end of airframe lives.
The Ocean seaplanes will be offered with the best low-carbon and zero-carbon emission power systems wherever missions allow. Aided by their useful-load and cruise-efficiency advantages, they are highly suited to electrification to enable viable zero-emission operations, also helped by the high value of short-range services provided by seaplanes.
Ocean Seaplane & GULL UAV Models Video