TITLE OF INVENTION:

VTOL aircraft with a thrust-to-weight ratio smaller than 0.1

CROSS-REFERENCE TO RELATED APPLICATION:

This application is claims foreign priority benefit of Patent Application EP 14075023.3 filed on 17 April, 2014 and US 14329949 filed on 13 July, 2014, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION:

[0001] This invention relates to aircraft, and more particularly, to aircraft with VTOL technology.

[0002] Currently, there are three kinds of traditional VTOL technologies which get vertical lift from high-speed air flowing over upper surface of the aircraft. In the first one such as patent No: US20120068020, a fan independent of a main engine increases speed of low-temp air flowing over the upper surface of wing along the direction of the chord, thereby increasing vertical lift. In this way, this fan less efficiently increases the vertical lift; In the second one such as patent No: GB792993, a high-temp bypass duct directs high-temp air by a valve from a nozzle of a jet engine to flow radially over the upper surface of the aircraft, thereby generating vertical life. In this way, the high-temp bypass duct generates the vertical lift more efficiently than the first one but the upper surface of the aircraft might be burnt up; In the third one such as patent No: GB2469621 , a low-temp bypass duct directs low-temp air, with a rotatable nozzle, from a low-temp duct of a turbofan engine to flow over the upper surface of the wing along the direction of the chord, thereby generating vertical lift. But another rotatable nozzle spouts high-temp air downwardly from a high-temp duct of a turbofan engine. In this way, the low-temp bypass duct generates the vertical lift more efficiently than above ways but thin slot outlet of the low-temp bypass duct, set in the direction of the chord, enables a part of vertical lift to lose in the long low-temp bypass duct and the problem, how to direct the high-temp air to obtain more vertical lift from the upper surface of the aircraft but not burn up it, is not solved. Because of these limitations, VTOL is impossible for aircrafts with a thrust-to-weight ratio smaller than 0.1 and more particularly for large one. BRIEF SUMMARY OF THE INVENTION:

[0003] The present invention, however, can achieve VTOL on aircraft with a thrust-to-weight ratio smaller than 0.1 , the aircraft comprising: ailerons; a turbofan engine including a low-temp duct with an openable and closable propelling nozzle and a high-temp duct with an openable and closable propelling nozzle; a low-temp bypass duct including an openable and closable inlet connected to the low-temp duct, an outer wall, an inner wall and a thin slot outlet set on the upper surface of the wing in the direction of the wingspan; a high-temp bypass duct including an openable and closable inlet connected to the high-temp duct, an outer wall and a thin slot outlet set above that one of the low-temp bypass duct in the direction of the wingspan.

[0004] According to its first characteristic, the following are true:

The low-temp duct, during forward flight, spouts out low-temp air directly under the opening of the propelling nozzle of low-temp duct and the closing of the inlet of the low-temp bypass duct.

The high-temp duct, during forward flight, spouts out high-temp air directly under the opening of the propelling nozzle of high-temp duct and the closing of the inlet of the high-temp bypass duct.

The low-temp bypass duct, during take-off /landing, directs, under the closing of the propelling nozzle of low-temp duct and the opening of the inlet of the low-temp bypass duct, the low-temp air from the low-temp duct to flow, in form of low-temp planar jet, over the upper surface of the wing in the direction of the wingspan, thereby generating a vertical lift and enabling the ailerons to control horizontal and vertical balances of the aircraft.

The high-temp bypass duct, during take-off/landing, directs, under the closing of the propelling nozzle of high-temp duct and the opening of the inlet of the high-temp bypass duct, the high-temp air from the high-temp duct to flow, in form of high-temp planar jet, above the low-temp planar jet in the direction of the wingspan, thereby generating another vertical lift and enabling the ailerons to control horizontal and vertical balances of the aircraft more efficiently

The thin slot outlet of the high-temp bypass duct, set above that one of the low-temp bypass duct, enables the high-temp planar jet not to burn up the upper surface of the wing during vertical take-off/landing.

BRIEF DESCRIPTION OF THE DRAWING: [0005] The attached drawings illustrate the invention:

Fig. 1 iis a side view of an aircraft with this invention during vertical take-off and landing,

Fig. 2 iis a top view of an aircraft with this invention during vertical take-off and landing,

Fig. 3 iis a rear view of an aircraft with this invention during vertical take-off and landing,

Fig. 4 iis J local view for Fig. 3.

Fig. 5 iis A-A Section for Fig. 4

Fig. 6 iis B-B Section for Fig. 4.

Fig. 7 iis part Section for Fig. 4.

Fig. 8 iis K local view for Fig. 3.

FFiigg.. 99 iis C-C Section for Fig. 8.

Fig. 10 is a side view of an aircraft with this invention during forward flight,

Fig. 1 1 is a top view of an aircraft with this invention during forward flight,

Fig. 12 is a rear view of an aircraft with this invention during forward flight,

Fig. 13 is M local view for Fig. 12.

FFiigg.. 1144 is D-D Section for Fig. 13.

Fig. 15 is E-E Section for Fig. 13.

Fig. 16 is part Section for Fig. 13.

Fig. 17 is N local view for Fig. 12.

Fig. 18 is F-F Section for Fig. 17.

DETAILED DESCRIPTION OF THE INVENTION:

[0006] Referring to above drawings, an aircraft with this invention comprises: ailerons (1 , 2); a turbofan engine (3) including a low-temp duct (6) with an openable and closable propelling nozzle (7) and a high-temp duct (4) with an openable and closable propelling nozzle (5); a low-temp bypass duct (15) including an openable and closable inlet (14) connected to the low-temp duct 6), an outer wall (16), an inner wall (17) and a thin slot outlet (19) set on the upper surface of the wing and in the direction of the wingspan; a high-temp bypass duct (9) including an openable and closable inlet (8) connected to the high-temp duct (4), an outer wall (10) and a thin slot outlet (12) set above that one (19) of the low-temp bypass duct (15) and in the direction of the wingspan.

[0007] Referring to Fig. (1-9), during vertical take-off/landing, the propelling nozzles (5, 7) of the low-temp duct (6) and the high-temp duct (4) of the turbofan engine (3) are closed. At same time, the inlets (8, 14) of the low-temp bypass duct (15) and the high-temp bypass duct (9) are opened. Then, the turbofan engine (3) starts to increase/reduce thrust gradually. Now, the low-temp bypass duct (15) directs low-temp air (18) from the low-temp duct (6) and enables it, in form of low-temp planar jet (20), to flow over the upper surface of the wing along the direction of wingspan, thereby generating a vertical lift and enabling the ailerons to control horizontal and vertical balances of the aircraft. Similarly, the high-temp bypass duct (9) directs high-temp air (1 1 ) from the high-temp duct (4) and enables it, in form of the high-temp planar jet (13), to flow above the low-temp planar jet (20) along the direction of wingspan, thereby generating another vertical lift and enabling the ailerons to control horizontal and vertical balances of the aircraft more efficiently. The thin slot outlet (12) of the high-temp bypass duct (9), set above that one (19) of the low-temp bypass duct (15), enables the high-temp planar jet (13) not to burn up the upper surface of the wing.

[0008] Referring to Fig.(10-18), during forward flight, the propelling nozzles (5, 7) of the low-temp duct (6) and high-temp duct (4) of the turbofan engine (3) are opened. At same time, the inlets (8, 14) of the low-temp bypass duct (15) and the high-temp bypass duct (9) are closed. Then, the low-temp air (18) and the high-temp air (11 ) spout directly out of the propelling nozzles (5, 7) of the low-temp duct (6) and the high-temp duct (4).

[0009] All the formulas and calculations for this invention are listed in Annex 1.

[0010] All the formulas and calculations used to retrofit an Airbus A-380 based on this invention are listed in Annex 2.

[001 1] This invention can be used to retrofit an existing aircraft to achieve VTOL or manufacture a VTOL aircraft with a thrust-to-weight ratio smaller than 0.1.

ANNEX 1 :

[0012]

P Atmospheric pressure (Unit: Pa)

R Ideal gas constant (Unit:/. K^. rnol- ¹

Po Low-temp jet density at the outlet (Unit:/c# /m ³ )

Pi Atmospheric density (Unit:/c#/m ³ )

P Jet density on the cross-section (Unit: kg/m ³ )

Pm Jet density of the shaft (Unit: kg/m ³ ) o Jet temp at the low-temp outlet (Unit: K)

7 Atmospheric temp (Unit: K)

T Jet temp on the cross-section (Unit: K)

V ₀ Jet speed at the outlet of low-temp bypass duct (Unit: m/s)

V0 Jet speed at the outlet of high-temp bypass duct (Unit: m/s)

V Jet speed on the cross-section (Unit: m/s) v _m Jet speed of shaft (Unit: m/s) h ₀ Jet height of the outlet (Unit: m)

Kl Jet height of the cross-section (Unit: m) h Jet height on the cross-section (Unit: m)

L Width of the outlet (Unit: m)

C Gas specific volume (Unit: m ³ /kg)

M Molar mass (Unit: kg/mol)

Q Air inflow of turbofan engine (Unit: kg/s)

B Bypass ratio of turbofan engine (Dimensionless

G Maximum take-off weight (Unit: T)

X Distance between any point and outlet

of low-temp bypass duct in jet direction (Unit: m)

X ₁ Distance between wing root and low-temp outlet

in jet direction (Unit: m)

Distance between low-temp outlet and crossover

point at which jet boundary intersects with trailing

edge of wing in jet direction (Unit: m)

Distance between wingtip and low-temp outlet in jet direction (Unit: m)

a Angle between jet boundary and trailing edge

of wing (Unit: °) β Angle between chord line of wing and long

side of outlet (Unit: °) γ Dihedral angle of wing (Unit: °)

δ Sweep forward angle of jet (Unit: °)

0 Included angle between axis of low-temp jet

and one of the high-temp jet (Unit: °)

Θ Sweep back angle of jet (Unit: °)

F Total vertical lift (Unit: T)

F ₁ Lift between wing root and low-temp outlet (Unit: T)

F ₂ Lift between low-temp outlet and crossover

point at which jet boundary intersects

with trailing edge of wing (Unit: T)

F ₃ Lift between wingtip and low-temp outlet (Unit: T)

F ₄ Downward pressure generated by slant

upward deflected jet (Unit: T)

F ₅ Thrust generated by jet of low-temp outlet (Unit: T)

F ₆ Thrust generated by jet of high-temp outlet (Unit: T)

b Constant (Dimensionless unit) d Constant (Dimensionless unit)

C Constant (Dimensionless unit) n S/N of turbofan engine (Dimensionless unit) n ₂ S/N of turbofan engine used in vertical

Take-off/landing (Dimensionless unit) n ₃ S/N of outlet of low-temp bypass duct (Dimensionless unit)

TWR Thrust-to-weight ratio of aircraft (Dimensionless unit)

[0013] According to thermodynamic, relative values of the enthalpy of various jet cross-sections are same each other when pressures of these jet cross-sections are equal and the value of surrounding gas is starting value.

[0014] And according to the feature of planar jet, it just spread on the flat which is perpendicular to the outlet section.

_Po V ₀ h ₀ LC(T ₀ -W = j PVL C(T - T dh

PoV ₀ h ₀ - - -) = \ pV (- - dh

VPpoo PPi' J J \P PPi»

[0015] And according to the similarity of velocity and density distribution on the various sections, h Vo(Po - Pi) = |( - Pi)Vdh

[0016] According to dynamic characteristic of jet, momentums of the various sections are same each other in case of equal pressures.

p ₀ Lh ₀ V = j pLV ² dh p ₀ h ₀ V = I pV ² dh = I (p -p ₁ )V ² dh+ I p _x V ² dh

Poh ₀ V£

(Pm-Pi mK

0.3682F _{oPo ^ 027g6 |} 0.1162ft _m y _mPl

(2) V _m (Po-Pi ^' hoVo(Po-Pi

[0017] Substitute (1) into (2):

[0018] Substitute (3) into (1)

[0020] Substitute (3), (4) into (2)

V Ldx

^■ l ₀ ² Ldx

[0021] Because of

h _m /0.12x \

-^- = 2.44 + 0.41

h ₀ \ h ₀ )

[0022] When X≤X ₂ or X≤ X ₃

- VI + bx ffT bx b /l + bx-1

dx =— I — In _, h C

x 2 I + bx + 1

0.17HftPo

O.mipo 1.2655 0.2655 0.2786 ² ( _Pl -po) ² 0.2324 ² 0.2324p _! 0.2324p _!

0.2786( _Pl -po) 0.2786( _Pl -p ₀ )

1 /i ₀ V ₀ ² L

X - X ^■ (5)

2 2.44x 0.12

1 h ₀ V ₀ ² L

X - X ^■ (6)

2 2.44x 0.12

[0023] When X ₂ ≤ X≤ X ₃

— X ₂ ) x tan a]dx (7)

[0024] When force is zero in body axis direction,

F* = F ₅ + F ₆

(F ₄ + F ₅ + F ₆ ) sin δ = (F ₅ + F ₆ sin Θ

_ 1

δ = sin -sin # (8)

F = n ₂ (_F + F ₂ +F ₃ ) cos β cos γ - n ₂ [F ₄ cos δ + F ₆ sin(0 + γ) - F ₆ sin(0 - 7)] (9) [0025] VTOL can be achieved once: F > G

ANNEX 2:

[0026]

n = 1-4

n ₂ = 1-2

n ₃ = 1-4

M = 29 kg/mol

Q(Air inflow of Trent 900 turbofan engine) = 1204 kg/s

B( Bypass ratio of Trent 900turbofan engine) = 8.5: 1

GiMaximum take— off weight of ^4380) = 560 T

T ₀ = 383tf

p ₁ = 1.293kg/m ²

[0027] Assuming:

Θ = 36.5°

1 1

F ^■ =— QV, o= - x 1204 x 211 = 127002W = 13 T

n ₂ 2

MP ₀ _ 101325 x 29 x 0.001

p = = ₌ o ₉ 232 kg/m ³

"RTo ^{" -} 8.31 x 383

h ₀ = 0.46m

L = 6m

1 8.5 i 85

⁰ p ₀ xLxh ₀ 0.9232 x 6 x 0.46 ¹

V ₀ ' = V ₀ = 211 m/s

1 1

F ₆ =—Qx—— -x v ₀ ' = H370.7368iV = 1.4 T

7^2 8.5 + 1

¾ = 11 m

¾ = 18 m

¾ = 32 m

a = 14°

β = 5°

7 = 5°

6» = 36.5°

0 = 2 x 16.3°

0.1488 VI + 19.2419^

F ₁ = 209832.582[2.9246inx + + 0.0312 r0.12 x 11

1 + 19.2419 x 2.44 + 0.41

0.46

-9.621 i

r0.12 x 11

1 + 19.2419 x 2.44 + 0.41

0.46

VI + 19.2419 x 2.44 x 0.41 - 1

+ 9.621 in

VI + 19.2419 x 2.44 x 0.41 + lj

= 209832.582 [6.0811 - 0.1301 - 0.0918 - 0.0873]

= 1211132.68N

= 124Γ (5)

0.46

F ₂ = 209832.582 <! 2.9246 In

2.44 x 0.41

+0.1488

r0.12 x 18 2.44 x 0.41

2.44 + 0.41

k 0.46

/Ω 1 7 x 1 8 \

1 + 19.2419 x 2.44 ( Q ₄₆ + 0.41J

+0.0312

r0.12 x 18

2.44 + 0.41

0.46

r0.12 x 18

VI + 19.2419 x 2.44 x 0.41 1 + 19.2419 x 2.44 + 0.41

0.46

9.621 in

2.44 x 0.41 r0.12 x 18

1 + 19.2419 x 2.44 + 0.41 + 1

0.46

VI + 19.2419 x 2.44 x 0.41 - 1

+ 9.621 in

VI + 19.2419 x 2.44 x 0.41 + lj

= 209832.582 [7.3757 - 0.1368 - 0.1015 - 0.0969]

= 1477326.2936W

= 151Γ (6)

0.2655 0· 711Ρι ο

1 +

0.1711po 1.2655 0.2786 ² ( _Pl -po) ² 0.2324 ² 0.2324p _! 0.2324p _!

0.2786( _Pl -po) 0.2786( _Pl -po)

/i ₀ tan a

)τ-ττ ώ

2.44 x 0.12 x L 2.44 x 0—.12

VI + dx Vi + - 1

/

0.1488

209832.582(1.8133 x [2.9246 inx +

/VI + 19.2419x VI + 19.2419x - 1

+0.0312■ 96?1 fa-—

x VI + 19.2419x + 1

0.0653[2.9246x - 0.1488inx -

21.3691 / 1 1 \

= 209832.582 1.8133 x 2.9246 in +0.1488

12.4578 V21.3691 12.4578/ Λ/1 + 19.2419 x 21.3691 VI + 19.2419 x 12.4578

+ ^{0'0312 1} 21.3691 12.4578

VI + 19.2419 x 21.3691 - 1 VI + 19.2419 x 12.4578 - 1

-9.621 In + 9.621 In

VI + 19.2419 x 21.3691 + 1 VI + 19.2419 x 12.4578 + 1

21.3691

-0.0653 [2.9246(21.3691-12.4578) - 0.1488in ^' . -_ ₀ - 0.0312 (2Vl + 19.2419 x 21.3691

12.4578

. VI + 19.2419 x 21.3691 - 1

-2V1 + 19.2419 x 12.4578 - In _,

VI + 19.2419 x 21.3691 + 1

VI + 19.2419 x 12.4578

VI + 19.2419 x 12.4578 + lj

= 209832.582(1.8133 x [1.5781 - 0.005 + 0.0312(-0.2953 - 0.2934)]

-0.0653 [26.062 - 0.0803 - 0.0312(9.5748 - 0.0305)]}

= 239636.5129W

= 24Γ (7) δ = sin ^"1 sin

= sin ^'1 si n 36. 5°^

= 17.3° (8) [0028] According to this sweep forward angle, low-temp planar jet enables the aircraft keep balances during vertical take-off/landing.

F = n ₂ (Fi + F ₂ + F ₃ ) cos β cos γ— n ₂ [F ₄ cos δ + F ₆ sin(0 + y)— F ₆ sin(0— y)]

= 2(124 + 151 + 24) cos 5° cos 5° - 2 [13 cos 17.3° + 1.4 sin(2 x 16.3° + 5°)

-lA sin(2 x 16.3° - 5°)]

= 568 T (9)

F - G = 568 - 560 = 8 Γ > 0

n ₃ (F ₅ + F ₆ ) n ₃ F ₄ 4 x 13

TWR = —— = -^ ¹ =—— = 0.09 < 0.1 (10)

G G 560

[0029] It is clearly demonstrated above that VTOL is achievable on Airbus A380 once remodeled as shown, and more particularly, in case of using just two turbofan engines and thrust-to-weight ratio smaller than 0.1.