JPH011698A - air levitation device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a VTOL aircraft (vertical take-off and landing aircraft),
The present invention relates to an airborne device comprising one or more ducted fans.

[Conventional technology]

The vroLa, which uses a ducted fan, was researched and prototyped mainly in the United States between 1940 and 1960, also known as a flying platform. Most of the machines were intended as military flying jeeps, but as a result, the stability and mobility did not meet military requirements and they ended in failure. This type of VTOLlal, devised in 1940 by Charles Zimmerman of Chancebauto, has a center of gravity above the rotor, allowing the pilot to stand upright above the rotor and control the aircraft simply by shifting his weight. The idea is to do so. Therefore, it was the smallest and most basic airplane, and it was extremely stable, which made a strong impression on the aircraft industry around the world, and continues to do so today. It was demonstrated in the 1950s using experimental machines such as the Hira-■2-1, and many documents were published in the United States from the late 1950s to the early 1960s. The one-seater Hira-■2-1 had a speed of 25km/h, but it hovered very easily, so even an inexperienced person could easily ride it. Taking this into consideration, the NACA and N
Numerous experiments were conducted at ASA. However, it showed significant dynamic instability and was canceled. However, all of these experiments ignored Charles Zimmerman's basic idea that the vehicle's center of gravity was in the plane of a flat duct. Moreover, if the center of gravity of the vehicle is placed below the aerodynamic center, there is a problem in that long legs must be provided, and there is also a problem in that lift loss occurs due to obstructing the shed flow path, and there is also a problem in that the vehicle falls in an accident. However, they do have the disadvantage of being dangerous to pilots.

Theoretically, there are four factors that make a ducted fan VTOL machine stable. In other words, as shown in FIG. 1, (a) When the hovering aircraft 1 moves horizontally, a pressure difference occurs in the duct lip portion 5, which causes a pitching moment M.
occurs.

(b) Since the flow passing through the rotor is regulated by the duct 4, even if the body 1 moves horizontally, it is always blown down vertically. For this reason, a resistance H occurs that attempts to prevent the movement of the aircraft.

(c) When the 81 body 1 makes a pitching motion, a pinch damping moment is generated in the rotor 6 and the duct 4.

(2>m Distance from center of gravity CG to aerodynamic center AC.

[Problem that the invention seeks to solve]

The reasons why the conventional ducted fan type VTOL aircraft mentioned above have not been put into practical use to date are that they require complex attitude control due to poor self-stability against tilting of the aircraft and movement in the propulsion direction; The reasons include that there was no demand for it due to its inferior fuel efficiency and limited use.

Regarding the self-stability of the aircraft, as mentioned above, if the center of gravity of the vehicle is placed below the aerodynamic center, the aircraft will become unstable, and it will also be necessary to have long legs, or increase lift to obstruct the shed flow path. Although there are problems such as losses and danger to the pilot if the pilot falls in an accident, even if the center of gravity of the vehicle is placed above the aerodynamic center, h is simply calculated without considering the diameter of the duct. There is a problem in that it is not possible to specifically set design conditions just by keeping the value within a certain positive range.

The present invention solves the above-mentioned problems, and is capable of ensuring self-stability even under the influence of external factors, and at the same time does not require special posture control. It is an object of the present invention to provide an aerial levitation device having a ducted fan.

[Means for solving problems]

To this end, the aerial levitation device of the present invention includes a body having one duct, a drive device fixed to the body, a rotor disposed in the duct and driven by the drive device, and a reaction force when the rotor is driven. In an aerial levitation device equipped with anti-torque canceling means for absorbing force torque, the ratio of the diameter of the duct to the distance between the center of gravity of the aircraft body and the aerodynamic center is set in a range that is stable against tilting of the aircraft body and movement in the propulsion direction. A fuselage having a plurality of identical ducts, a drive device fixed to the fuselage, and a rotor disposed within the duct and driven by the drive device,
In an airborne device equipped with anti-torque canceling means for absorbing reaction torque when the rotor is driven, the plurality of ducts are arranged so that the total lengths in the vertical and horizontal directions are approximately the same, and the center of gravity and the aerodynamic center of the aircraft are arranged. It is assumed that the ratio of the diameter of the duct to the distance is set to a range that is stable against tilting of the aircraft and movement in the propulsion direction.

[Action and effect of the invention]

The present invention includes a body having one or more ducts, a drive device fixed to the body, a rotor disposed in the duct and driven by the drive device, and a reaction torque when driving the rotor. In an air levitation device equipped with an anti-torque canceling device that absorbs a As a result of converting it so that it becomes a function of the diameter ratio of It turns out that there is a region.

By adopting the ratio of the diameter of the duct to the distance between the center of gravity of the stable aircraft and the aerodynamic center as a design condition, it is possible to ensure self-stability even when affected by external factors, and A floating device that does not require special attitude control can be obtained.

〔Example〕

Examples will be described below with reference to the drawings.

Fig. 1 is a schematic diagram of an air levitation device equipped with one ducted fan according to the present invention, Fig. 2 is a diagram for explaining the drive mechanism of the counter-rotating rotor in Fig. 1, and Fig. 3 is a diagram showing a horsepower load and a disk. A diagram showing the relationship with load, Part 4 (A) is a diagram showing a model of a ducted fan, and Part 4 (C) is (A)
Figure 5 (a) and (b) are diagrams showing a model of a two-duct fan, Figure 6 (a) is a diagram showing calculation results and experimental results of pitch damping, Figure 6 (B) is a diagram for explaining the displacement of the blade, Figure 7 is a diagram showing the relationship between the size of the duct lip and the lifting force, Figures 8, 9 (A) and 9 (Ro) ) is a diagram for explaining a stable region, FIG. 10 is a schematic diagram of an air levitation device equipped with a plurality of ducted fans of the present invention, and FIG. 11 is a diagram for explaining an example of arrangement of a plurality of ducted fans.

In the figure, 1 is an airborne device, 2 is a main body, 3 is an engine, and 4
is the duct, 5 is the duct lip part, 6 is the counter-rotating rotor,
7 is the support leg, CG is the center of gravity of the aircraft, AC is the aerodynamic center, m is 1tffi of the entire vehicle, U is the horizontal movement speed of the vehicle center of gravity, Uo is the horizontal movement speed of the duct, T is the thrust, and θ is the pitch attitude angle of the vehicle. , H is the horizontal aerodynamic force acting on the ducted fan, ■ is the mass inertia rate of pitching, M is the pitching moment acting on the tarite and fan, h is the distance from the aerodynamic center (AC) of the ducted fan to the vehicle center of gravity (CG) .

First, we performed a stabilization analysis of an airborne device equipped with one ducted fan, and then demonstrated that the same method of stabilization analysis as for one ducted fan is possible for an airborne device equipped with multiple ducted fans. do.

In FIG. 1, the floating device l includes a main body 2 and a main body 2.
The duct 4 is provided with a duct lip portion 5 for generating lift, and the duct 4 includes a counter-rotating rotor driven by the engine 3. 6 are disposed, and support legs 7 are provided on the lower surface of the duct 4.

As shown in FIG. 2, the counter-rotating rotor 6 has rotors 6a and 6b that rotate in opposite directions. One rotor 6a is connected to the crankshaft 10 of the engine 3 equipped with a sun gear 9, and the other The rotor 6b is the carrier 11
is connected to.

The carrier 11 is rotatably provided with double pinions 12.13 of 2 to 5 cents on the same circle, and the double pinions 12.13 mesh with each other, one double pinion 12 meshes with the sun gear 9, and the other double pinion 12.13 meshes with the sun gear 9. The double binion 13 is meshed with a ring gear 14 fixed to the main body 2.

By making the number of teeth of the ring gear 14 twice the number of teeth of the sun gear, the rotor 6 is driven by the engine 3.
a and 6b are equally rotated in opposite directions to cancel out the reaction torque generated by the rotation of the rotor.

Next, the conditions for self-stability of the air levitation device 1 will be analyzed.

The thrust (lifting force) of the aircraft is T5 power is P, the air density is ρ,
If the cross-sectional area of the flow inside the duct is A, and the axial flow velocity at the duct outlet is ■, then T=ρAV", P=TV/2... (1
) Therefore, P=-T3/2/J7 Sue... (2) Also... ■
=, /”Self/p15 ... (3) Therefore, if the volumetric flow rate is ■, then V -A, V -n7 tons ... (4) Effect on the ducted fan when there is a slight duct forward speed UI + The resistance T is H = (ρA ■) U o ”' T U o / V
...(5) The above is an ideal state based on simple momentum theory. Furthermore, H in equation (5) does not include harmful resistance. The resistance H is not the square of the moving speed Un, but the first power, so it is very large even at low speeds.

Also, the circumferential speed of the tip of the fan is V? If we set T/ρAVT2-dimensionless number...(6), then T/A-(dimensionless number)×ρV,2...(6') Therefore, the fan blade tip speed Va is constant. Then, the disk load T/A is not affected by the dimensions of the duct. Also,
According to equation (3), ■ is also not affected by the dimensions of the duct.

Next, when analyzing the self-stability of the aircraft, the equation of horizontal motion of the center of gravity of the vehicle and the equation of rotational motion around the center of gravity of the vehicle are as follows: m: Mass of the entire vehicle U: Horizontal movement speed of the vehicle center of gravity U11 = Horizontal movement speed of duct T: Thrust θ: Vehicle pitch attitude angle, positive head elevation, radl-1
:Horizontal aerodynamic force acting on the ducted fan, backward positive 1: Pitching mass inertia M: Pitching moment acting on the ducted fan, positive head elevation around AC h: From the aerodynamic center of the ducted fan (A C) to the vehicle center of gravity (CG) Distance θ: dθ/dt θ, d2 θ/d t” Here, ...(8) Therefore, the equations (7) become as follows.

...(9) Furthermore, it is made dimensionless as follows.

M=TDM=mgDM, U/V=u, 1...
・If we set (10), equation (9) becomes...(11). Here, if we set u=u, e'τ, θ-θ e3τ (12), then equation (11) becomes...(13). Both equations of equation (13). If you delete...
(14) is obtained. In order for the system having the characteristic equation 2 (14) to be stable, that is, to match the target value, it is necessary to satisfy the following Routh condition.

A, B, C>0. AB-C>0 (15) The following simple relational expression is also added.

Equilibrium velocity: u=-θ, h-M, =O. (17) Next, Mu in the above equation (14), 1. Let's check the values of M and -g under certain conditions.

FIG. 3 shows the relationship between the horsepower load and the disc load at the entrance of the variable hen when the blade angle is 10 degrees. In the figure, the ideal hovering efficiency E = 1.0 is obtained by transforming equation (2) as log(T/P) = Iog2v/7-1/2
1og(T/A) and is shown in a double-logarithmic graph.Actually, the air resistance of the rotor, the non-uniformity of the air flow in the duct, the viscous frictional resistance of the air flow near the duct wall surface, etc. Loss reduces efficiency. According to this, the disc load T/A is 2 to 207! b/fLZ.

That is, it is between 10 and 1 OOkg/rd. ρ=122
Since there is +r/ite in V'-% = 9 to 30 m
/seC.

Figure 4 (a) shows a model of a ducted fan with D = 28 inches, and Figure 4 (b) shows the results of a wind tunnel test, showing the pitching moment M acting on the ducted fan at thrust T = 3 (lb) and the vehicle center of gravity. The relationship with horizontal movement speed U is shown.

Here, r is the lip radius of the duct, D is the inner diameter of the duct, θ
indicates the inclination angle of the duct with respect to the wind tunnel flow. As a result, when the duct lip is large, U = o ~ 8kt and 21M/aU = 1rt-zb /kL, so V
-5=16.4 m/sec. From this, g = g D/V'' ~0.026 is obtained. And... (l 8) is obtained.

FIG. 5 has two ducted fans. Here, D = 28', m-80 Ab, the inertia factor around the major axis is 1-2.2 slog-ft'', and from this, as a close analogy to a vehicle with 1 ducted fan, 1-1/mD'' - 0,1625-(19) is obtained. This is a model of the distance between the center of gravity and the aerodynamic center of the aircraft, hζ0, but it is much larger for aircraft with the center of gravity above. Therefore, set 〒=0.16X (X>1).

Figure 6 shows the relationship between pinch damping and the rotor spring coefficient published in Akira Naito's paper ``Pitch damping of ducted fans'' in the Journal of the Japan Society of Aeronautics and Astronautics, Vol. 31, No. 352. In the figure, the curves are calculation results and the points are experimental data, but in any case, the pitch damping that occurs in the rotor and duct when the aircraft makes pitching motion is d (q/Ω) ↓n box 0.There is.As shown in Figure 6 (b),
C is the moment coefficient around the hub of the rotor, 9 is the pitching angular velocity, and Ω is the rotor rotational angular velocity.

If we replace the left side with the current symbol, we get (V / V t ) Mo', so -Mo'
−(0,05~0.15) VT /V= (0,
05~o, t5) /, 7'ji7W41= (0,05
〜0.15) /载...(21). (KL is the lift coefficient) Figure 7 is a diagram showing the relationship between the lift coefficient KL and (horizontal movement speed U of the vehicle center of gravity/fan blade tip speed VT), where KL = 0.03 for the one with a large duct lip radius. suggests. Therefore, the formula (21) or the % formula % is obtained, and the intermediate value is 0.587. Although the above-mentioned parameter values are not necessarily consistent values, if these values are adopted, Equation (14) becomes... (23) In Figure 8, X-1 , 5, the relationship between AB and h and the relationship between C and h were plotted. Stability condition is AB-Coo
Therefore, the stable region is in an extremely narrow portion of h#l. There is no stable region at h x 0. This proves the validity of Charles Zimmerman's basic ideas. It is understood that when X is set from 1 to 5, the stability region becomes even narrower.

In the self-stability analysis described above, a stable region was obtained by calculating each numerical value according to a specific model.Next, a simpler approximate design method will be explained.

For this purpose, set C-0, that is, h=MII. At that time, the formula (14) is A=g (I-M(f)/I, B>0.C=0...
(24), suggesting neutral stability. Also, the expression (
The equation of motion for 11) is...(25). Therefore, θ can be solved independently of U.

If we put that θ into the above equation of (25)2, we can solve U.

Initial condition, τ-0, u''u6, θ-θ., θ'-θ'. ...Given (26), ...(27) with θ at the -head, u -= O. It shouldn't be θ,, uoo
is finite. This is the reason why it is neutral and stable. what if,
Using the numerical values of equation (22) and the initial value of... (28), oct, = 0.2, U- = -3,3m/sec -
(29), which is a calm and straightforward character. Also, −−(
θ6 + u 6 + Mu θ'o) = -o, 2...
・(30) In other words, the initial acceleration is also gentle.

The results of numerically calculating the characteristic root S of the characteristic equation (14) with respect to X=1 are shown in FIGS. 9(a) and 9(b).

Figure 9 (B) is a detailed view of the vicinity of the origin of Figure (A).
In order for the aircraft to be stable against tilting and movement in the propulsion direction, it is necessary that U and θ converge to 0 at t-■.

That is, when the characteristic root S is a real root, it is all negative, and when it is a complex root, it is stable only when all the real parts are negative.

Therefore, there is a stable region within the narrow width shown in FIGS. 9(a) and 9(b). As the line of the imaginary part of the complex root shows, there is an oscillatory divergence at h=o, and this (injection amount is h
--It continues until about 1. Conversely, when h=1 to 2, non-oscillatory divergence appears. That is, it can be seen that there is a miraculous stable region only near the h slope. In other words, what should be noted about the above design method with C=O is that the vehicle is not tilted in response to horizontal crosswind gusts, but is simply swept sideways, so the ductless rotor type capsized due to the gust. This can prevent such accidents.

As explained above, the airframe includes a body having one duct, a drive device fixed to the body, and an anti-torque canceling device arranged in the duct and driven by the drive device. In an airborne levitation device, an equation of motion is established for the inclination of the aircraft and movement in the propulsion direction, and the coefficients of the characteristic equation are converted to become a function of the ratio of the diameter of the duct to the distance between the center of gravity of the aircraft and the center of aerodynamics. However, as a result of determining the stability conditions for the aircraft, it was found that there is a region where the aircraft is stable within a limited range where the ratio of the diameter of the duct to the distance between the center of gravity and the center of aerodynamics is positive.

By adopting the ratio of the diameter of the duct to the distance between the center of gravity and the aerodynamic center of this stable aircraft as a design condition, it has excellent self-stability and a special attitude system. Thus, it is possible to obtain an airborne device that does not require an N device.

next? We will analyze the attitude stability of a floating device supported by JjB's ducted fan. First, it is assumed that the vertical motion in the x-z plane and the horizontal motion in the y-z plane are independent of each other. Lateral motion does not include yaw motion, unlike in airplanes. Also, while ignoring mutual interference between each ducted fan,
All ducted fans within one vehicle shall be identical. Furthermore, as shown in FIG. 10, the aerodynamic center AC of each ducted fan is in the same plane, and the center of gravity CG of the aircraft is the thrust force T of each ducted fan.

It is above the AC plane on the resultant force T line.

Now, in the equation of motion (7) mentioned above, M=nM,
, H-nH, T-nT, ... (31) too. M,
, H, , T are the pitching moment, horizontal aerodynamic force, and thrust of each ducted fan, and n is the number of ducts, which will be described in detail later. Also, the pitching 'ffi! The inertia factor l and the vehicle quality ff1m are those of the entire vehicle.

Here, the equation corresponding to equation (8) is: T=mB H,=Ti un /v I(-ΣH1=(ΣTr) Uo/V=T
IJ++/V (8') The flow velocity vI passing through the duct is the same for all ducts, and V=V. Also, the horizontal movement speed of the ducts is the same for all ducts, and u, = u + hθ
...(8').

Therefore, equation (8) in the case of one duct remains unchanged even if the number of ducts is increased, and therefore equation (9) also remains unchanged.

Next, the number n of ducts in the above equation (31) will be explained with reference to FIG.

The number of ducts when considering movement in the vertical direction (X direction) is n
8. When considering the movement in the lateral direction (Y direction), let n be the number of ducts, then in the figure (A), n8-2, ny
=1, (b) In the figure, nx-2, n, -2, (c)
In the figure, n1I=5, n, -5, and n in equation (31) is determined for each of the vertical and horizontal movements.

Next, (1) Equation (9) is made dimensionless so that Equation (11) in the case of a ducted fan remains unchanged even when the number of ducts increases. First, U/V=u is fine, but the rest of 2(10) has careful consideration. Formula (1
Let the dimensionless lengths used in M, g, h, f, and t of 0) be 18, β9, βk, "'I, and β1, respectively, and the determination will be done later conveniently. That is, M= Tffi, M., U/Vyu.

ga (V”/Il,)g, hmireh, IEEMl,
” I, Lmi τ(i!L/y)... (10') and substitute this into (9) 2, Re'Rden.

=0 '9 ''l ' I9 β,'... (II') In order for this equation (11') to be the same as the above equation (11), the following equation must be established.

1t=6. -11. ...(32)1
2h At! =i19L! + ” ”' (
3311's jet " = L I!! 1 "
...(34) Therefore, I2. =/, =6. −β,=j! I... (35
), and one of them is arbitrary, and once it is determined, all the others are determined.

When considering the vertical motion of the vehicle, for example, the total vertical length Lll of the duct exit can be selected as itL, and when considering the horizontal motion, the total horizontal length of the duct exit can be chosen as I.
You can choose it as L.

Then, the vertical or horizontal motion is the same as in the case of one duct, and for the vertical motion, hxζL, lhw for the horizontal motion, h,';L,h.

h, l#hy (36). Therefore, unless L, = L, h = h
, = h, it is not possible to stabilize the vertical and horizontal motions at the same time.

This makes it clear, for example, that the duct arrangement shown in FIGS. 11(a) and 11(c) is unstable, and that the duct arrangement shown in FIG. 11(b) is stable.

Furthermore, the arrangement of (d), (e), (e), and (g) is also stable. Furthermore, it can be easily developed even in the case of an axially symmetrical arrangement as shown in (H) and (S).

As a result of the above analysis, the following became clear.

■Longitudinal or horizontal motion can be analyzed using the same formula as for a ducted fan by selecting only one arbitrary reference length for each.

■In order to maintain vertical and horizontal stability at the same center of gravity CG position, the vertical and horizontal reference lengths must be almost the same.

■The standard length can be determined somewhat arbitrarily. However, it must meaningfully indicate the length and width of the vehicle. Therefore, it is desirable for stability that the vertical and horizontal alignments be approximately the same.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible. For example, in the above embodiments, an engine is used as the drive source, but an electric motor may also be used.

Furthermore, in the above embodiment, a planetary gear mechanism is used as the counter-rotating rotor drive mechanism as the anti-torque elimination means, but if two drive devices are provided, each rotor may be driven independently. . Alternatively, the rotation may be reversed with symmetry between the front and rear and left and right sides of each ducted fan. Furthermore, by installing variable vanes in the duct population and adjusting the angle of the variable vanes, counter torque can be eliminated and roll, pitch, and yaw attitude control can be performed, making the aircraft even more stable. It will improve.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an airborne device equipped with one ducted fan according to the present invention, Fig. 2 is a diagram for explaining the drive mechanism of the counter-rotating rogue in Fig. 1, and Fig. 3 is a diagram showing a horsepower load and a disc. Diagram showing the relationship with load, Figure 4 (a) is a diagram showing a model of a ducted fan, Figure 4 (b) is (a)
Figure 5 (a) and (b) are diagrams showing a model of a two-ducted fan, and Figure 6 (a) is a diagram showing the calculation results and experimental results of pinoch damping. , FIG. 6(B) is a diagram for explaining the displacement of the blade, FIG. 7 is a diagram showing the relationship between the size of the duct lip and the lifting force, FIGS. 8, 9(A), and 9( B) is a diagram for explaining the stability region, FIG. 1O is a schematic diagram of an air levitation device equipped with a plurality of ducted fans of the present invention, and FIGS. FIG. ■...Aerial levitation device, 2...Main body, 3...Engine, 4...Duct, 5...Duct lip part, 6...
- Double rotating rotor, 7... Support legs, CG... Center of gravity of the aircraft, AC... Center of aerodynamics, m... Mass of the entire vehicle, U... Horizontal movement speed of the center of gravity of the vehicle, UD...・Horizontal movement speed of the duct, T...Thrust, θ...Pitch attitude angle of the vehicle, H...Horizontal aerodynamic force acting on the ducted fan, I...Pitching quality it inertia factor, M
...Pitching moment acting on the ducted fan, h...Distance from the aerodynamic center (AC) of the ducted fan to the vehicle center of gravity (CG). Figure 2 S - no, 2, - analysis of 3-single single edge Figure 4 2 C1: lim: 12 and 2 + 0152 knajs ko'-7" le 1IX-:: < half sum 25 positive, t Ll 5th
Figure (A) (A) β (B) Figure 7 06-i 0 , . 05. 10. 1
5 Figure 8 Figure 9 (B) Figure 10 7'' / U / ←--]ゝMori CL: F j Figure 11 (A) Fang (C) Chi Figure 11 (D) (/↑・) (to) (top)

Claims (4)

[Claims] (1) A fuselage having one duct, a drive device fixed to the fuselage, a rotor disposed inside the duct and driven by the drive device, and a rotor that absorbs reaction torque when the rotor is driven. and a torque canceling means, characterized in that the ratio of the diameter of the duct to the distance between the center of gravity of the aircraft body and the aerodynamic center is set in a region that is stable against tilting of the aircraft body and movement in the propulsion direction. An air levitation device. (2) Establish an equation of motion for the tilt of the aircraft and movement in the propulsion direction, convert the coefficients of the characteristic equation so that they become a function of the ratio of the duct diameter to the distance between the aircraft center of gravity and the aerodynamic center, A patent claim characterized in that by determining stability conditions for the aircraft, the ratio of the diameter of the duct to the distance between the center of gravity and the aerodynamic center of the aircraft is set to a region that is stable against tilting of the aircraft and movement in the propulsion direction. Aerial levitation device according to item 1. (3) A fuselage having a plurality of identical ducts, a drive device fixed to the fuselage, a rotor disposed within the duct and driven by the drive device, and absorbing reaction torque when the rotor is driven. In the aerial levitation device, the plurality of ducts are arranged with substantially the same length in the vertical and horizontal directions, and the ratio of the diameter of the duct to the distance between the center of gravity and the aerodynamic center of the aircraft body is An aerial levitation device characterized in that the air levitation device is set in an area that is stable against tilting of the aircraft and movement in the propulsion direction. (4) Establish an equation of motion for the aircraft's tilt and movement in the propulsion direction, convert the coefficients of the characteristic equation so that they become a function of the ratio of the duct diameter to the distance between the aircraft's center of gravity and the aerodynamic center, A patent claim characterized in that by determining stability conditions for the aircraft, the ratio of the diameter of the duct to the distance between the center of gravity and the aerodynamic center of the aircraft is set to a region that is stable against tilting of the aircraft and movement in the propulsion direction. Aerial levitation device according to item 3.