NEW FLIGHT MODEL

A novel revolutionary universal flight theory with resulting flight model for aircraft comprising two large fixed and highly tapered wings characterized by extremely elongated chords and balanced airfoils that have ultra low average t/c ratio (<5%) with gravity center (G.C.) set deep in-between the centers of pressure (C.P.) of both wings.

AIRFOIL FEATURES

The aerodynamic features of custom airfoils with G.C. set deep between wings' C.P. allow both wings to be fully involved in positive cruise lift production with the same optimal lift efficiency and their full contribution to natural pitch stability unlike a simplified single-wing flight model with aft-camber airfoils that have G.C. set in front of both wing and tailplane.

RESULTING CHANGE

These two fundamental changes involving G.C. position relative to planar lifting surfaces and aerodynamic characteristics of airfoils removed strong natural limitations of single-wing flight model, whereby both wings assisting each other to reach the highest possible level of flight safety and efficiency in all flight regimes.

EXTRA LIFT PRODUCTION

Extra lift production during takeoff and landing is substantially additionally increased with significant ground effect generated by the large low-cantilever Front Wing with multiple times larger area and longer chords when compared to the present-day aircraft.  Lift area increase of both wings via chord elongation that is needed for a higher level of flight safety in cruise is also very beneficial at low speeds during takeoff and landing to reduce the critically important T/O runway length and provide for safe landing.

WING AIRFRAME SIMPLIFICATION

High taper ratio of wings is resulting with their significantly increased structural resistance to stress.  The removal of leading edge slats, devices for extra lift production on trailing edge, as well as the shift of engines to the fuselage aft portion along with pivotal-only trailing edge devices allow for a significant simplification and uniformity of wing design with subsequent weight reduction despite the substantially increased wing area.

WEIGHT REDUCTION

Long wing root chords of both wings include a number of longerons for a full structural integration with fuselage to eliminate heavy concentric joints, whereas together with the spread of lifting forces over two wings is resulting with further weight reduction of both fuselage and wings.  The reallocation of wing-podded engines to the fuselage aft-section allows for the shortening of landing gears and reduction of their weight that along with a high ground effect due to highly elongated Front Wing chords and a substantially increased overall wing area is resulting with a significant reduction of engines' rated power, their size, and weight. All of the above is resulting with airframe weight reduction despite significantly increased wing area.

DRAG REDUCTION

Airframe weight reduction and multiple times increased total wing area even with the substantial partial reduction of lift coefficient on both wings allow for the flights at a much higher altitude with significantly reduced air density, thus resulting with the reduction of drag of all aircraft sections.  A partial substantial reduction of lift coefficient with the square value thereof is reducing induced drag coefficient that together with a substantially recovered aspect ratio of both wings close to present-day aircraft due to wide tiplets despite a high taper ratio are multiple times reducing induced drag coefficient and total induced drag despite multiple times larger lifting area of both wings. 

Progressively increased chord lengths towards the wing root due to a high taper are increasing bending and torsion structural resistance of wings.  Simultaneously, a lower lift coefficient is reducing transversal forces across the span, whereas a high taper is resulting with a substantial shift of lifting forces towards the wing root console, thus substantially reducing bending and torsion momentums.  Increased structural resistance, as well as reduced transversal forces with reduced bending and torsion momentums allow for a multiple times reduction of t/c ratio of wing sections down to 4%. 

Multiple times reduced lift coefficient in combination with multiple times reduced t/c ratio are almost proportionally reducing wing profile drag.  Simultaneously, multiple times reduced lift coefficient and t/c ratio are increasing critical Mach Number (Mcr) beyond M0.85 towards M0.9.  Additionally, combined with multiple times longer chords, it is resulting with the reduction of the height of the local wave shock at transonic speeds and fast recovery of subsonic flow and consequently maintaining the cruise lift coefficient.  

All of the above effects are increasing the economical cruise speed substantially towards the speed of sound.  Higher economical cruise speed with its square value is increasing the total lift and results with the further increasing of cruise altitude and therefore resulting with the additional reduction of total aircraft drag.  Additionally, a higher economical cruise speed is reducing the total flight time in a linear manner and thus reducing the required total fuel weight. 

HYDROGEN USE

The above-resulting significant required total energy reduction in turn allows for the realistic use of Liquid Hydrogen (LH2) that has a sizeable gravimetric advantage over fossil fuels without paying a high cost for a significant volumetric disadvantage over fossil fuels, thus substantially lowering the barrier for use of liquid hydrogen and resulting with a further weight reduction of aircraft for flights at even higher altitudes (up to 20 km) and therefore further resulting with additional increase of flight efficiency of up to 70% relative to present-day single-wing aircraft with zero-carbon emissions.