AU2009100997A4 - Amphibious airplane with engine on inverted v-tail - Google Patents

Description

5 claims, 14 drawings/images Figure 1: General Three Dimensional View .................................................................... 6 Figure 2: T op V iew ........................................................................................................ . 7 Figure 3: Front V iew ...................................................................................................... . 7 Figure 4 : B ottom V iew ................................................................................................... . 8 Figure 5: Side V iew ...................................................................................................... . . 8 Figure 6: Three Dimensional View.................................................................................. 9 Figure 7: Three Dimensional View With Detachable Centre Pod.................................. 9 Figure 8: Three Dimensional View With Dropped Centre Pod..................................... 10 Figure 9: Three Dimensional View With Folded Wings ................................................ 10 Figure 10: Top View With Wings In Sailing Position...................................................... 11 Figure 11: Three Dimensional View With Wings In Sailing Position .......................... 12 Figure 12: Savoia-Marchetti S-55 of Aeroflot, 1933.................................................... 12 Figure 13: Lake LA-4-200 Buccaneer ........................................................................... 13 Figure 14: Seaw ind 3000 ............................................................................................... 13 References cited: 1. NACA Technical Note No. 504 "Complete tank tests of two flying boat hulls with pointed steps" 2. NACA Research Memorandum No. L7110 "Hydrodynamic characteristics of a low drag, planing tail flying boat hull" 2 TWIN HULLED AMPHIBIOUS AIRPLANE WITH ENGINE ON INVERTED V-TAIL The main feature making this amphibious airplane design unique is the integration of the engine nacelle [1*] into the inverted V-tail [2]. An inherently stiff structure is created by the two nearly perpendicular empennage surfaces, which lends itself for the purpose of carrying an engine(s) [Figure 1, Figure 2, Figure 3, Figure 6]. Although mounted above the wing plane out of the water spray, the engine does not require a separate pylon or struts for that purpose [Figure 12 and Figure 13]. Elimination of these features reduces aerodynamic drag commonly associated with an elevated engine mount. The inverted V tail configuration will likely reduce the structural weight compared to a single vertical stabilizer used to carry an engine [Figure 14]. A piston engine or rotary engine with tractor propeller or two engines in a tandem arrangement with an additional pusher propeller are conceivable engine options for a light airplane version. Turboprop engines or one or more turbofan engines in a side by side configuration could power higher performance versions. The outer wing panels also function as sails, thereby enabling the aircraft to travel on the water without use of engine power, which can be vital in case of an emergency water landing or just enjoyable for recreational purposes. The wing panels [5] outboards of the hulls can be folded up to a near vertical position [Figure 9]. In this position, the wing panels also can pivot around a vertical axis, the angular travel being controllable by the operator [Figure 10 and Figure 11]. This enables the operator to position the wing in an optimum angle in relation to the wind for each heading, in the same way the sails are controlled on a sailing ship. Another benefit of the folding wings is to provide the capability of side mooring, which can be difficult or impossible for monohull flying boats, but is quite common for floatplanes. The outer wings can also be completely detached for transport and storage, or for operating the craft as a boat. The wing plan form features a medium to high aspect ratio and may have a sweepback. The latter would be applied in a high performance aircraft version flying at higher subsonic speeds, or in a light plane version for weight and balance reasons. The twin hulls [6] are asymmetric and can be thought of as one half of a single symmetric hull [Figure 2, Figure 3, Figure 4]. This increases their length-to-width ratio, which reduces hydrodynamic drag in displacement mode, as in many catamaran ferries. Negotiating rougher water by slicing through waves rather than bouncing off them will be possible due to a narrow cross section and sharper bow compared to a wider monohull or traditional floats. The stability on the water and the seagoing capability of this catamaran design is likely to be superior to both of the above, due to its width and low centre of gravity. Numbers in brackets []refer to numbers in drawings/images. Number may occur in more than one image. 3 Each hull bottom contains an asymmetric, surfboard-shaped planing surface [7] with variable keel angle, which terminates in a point [8] rather than the traditional straight edged step well aft of the centre of gravity [Figure 7]. The desired effects are: 1. Less hydrodynamic drag, compared to straight edged step, when still in displacement mode. 2. Reduction of the tendency to porpoise during take-off and landing. 3. Less aerodynamic drag, compared to straight edged step. Experiments by NACA with similar shapes confirm that these effects can be achieved at least under certain operating conditions [Reference 1, 2], but the design has never been applied to an asymmetric float or hull. The hulls also may contain a retractable landing gear with a total of two main wheels and two nose or tail wheels. A permanent cargo area can also be located in the hulls. The central fuselage may house the cockpit and a passenger compartment. For large versions, the central fuselage may be omitted, because the cockpit, passengers and cargo can all be placed in the catamaran hulls to reduce aerodynamic drag. A similar design has been realized in the successful Savoia-Marchetti S-55 of the early 1930's [Figure 12], which, however, features a traditional empennage and engine mount. A detachable cargo pod [9] can be fastened to the bottom of the permanent central fuselage [Figure 7 and Figure 8] or the central wing portion. This pod can have functions as follows: 1. Additional payload space 2. Separable boat 3. Emergency life boat 4. Water container for aerial fire fighting 5. Sea rescue capsule 6. Container for dropping emergency supplies For the last purpose, the pod can descend on a steerable parachute, remote controlled from the ground or from the mother plane. This would enable very accurate placements of supplies in an emergency zone, or similar scenarios. Unmanned aerial vehicle (UAV) versions of the aircraft could operate autonomously or remote controlled for fire fighting, search and rescue or other purposes, without risking pilots' lives. Cameras and electronic equipment can be installed at the front and rear of the centre fuselage [4] without being obstructed by the engine, propeller or empennage. 4

Claims (5)

1. A powered seaplane/amphibious aircraft, whose means of propulsion is mounted on top of an empennage shaped like an inverted "V", which connects two parallel catamaran hulls.

2. Seaplane/ amphibious aircraft as described in [I.] whose asymmetric hull planing surfaces are surfboard shaped, meaning their rear ends terminate in a point instead of a traditional straight edged step.

3. Seaplane/ amphibious aircraft as described in [I.] with asymmetric shape of hull bulkhead cross section, like in offshore racing boats, but applied to aircraft.

4. Seaplane/ amphibious aircraft as described in [1.], whose outer wing panels also function as sails to propel the aircraft on the water without engine power.

5. Seaplane/ amphibious aircraft as described in [1.], with a multifunctional central pod, which can be dropped while airborne and has a remote controlled, steerable parachute. 5