7 Flight Mystery and Aerodynamic Principles
473
plane, a person lies on the wing, and the horizontal tail is placed in front
of the wing; this arrangement is called the canard layout. The layout of the
Wright brothers’ aircraft is different from the aircraft that is often seen today.
If the horizontal tail is placed behind the wing, it is called the conventional
layout; if the horizontal tail is placed in front of the wing, it is the layout of
the Wright brothers, called the canard layout. The flight control principle of
these two layouts is different during flight. The flight stability of the conventional layout is better, so the civil aircraft uses this layout. The canard layout,
although poor in stability, has good maneuverability, so fighters often use
this layout. For example, the Chinese J-10 fighter placed the horizontal tail
in front of the wing. The tail that is placed in front is called the canard, and
the tail placed behind is called the horizontal tail.
The speed of the early aircraft was relatively small, so the first problem
encountered was the insufficient lift generated. How to generate a large
enough lift to fly the aircraft is the key to the early design and manufacture
of the aircraft. Since the aerodynamic force of the aircraft is proportional to
the square of the flight speed, when the flight speed is small, the aerodynamic force generated under the same wing area is also small, but the weight
of the aircraft cannot be reduced, so measures to increase the wing area are
taken. But considering the factors in the structure of the wing, the layout of
two-layer wing and even the three-layer wing appeared in the early aircraft.
The three-layer wing layout was created because the two-layer wing was not
enough, so the three-layer was created (as shown in Fig. 7.35). Because the
flight speed is relatively small, the drag is not highlighted compared to the
lift.
According to the definition of Langley et al., the lift expression of the
aircraft is
L =
1
2
ρV
2
∞ C L S
V ∞ is the inflow velocity (the flying speed of the aircraft), S is the characteristic area of the wing, C L is the lift coefficient of the wing. The drag
expression is
D =
1
2
ρV
2
∞ C D S
where D is drag of the wing (parallel to the direction of flow), C D is the drag
coefficient of the wing.
473
plane, a person lies on the wing, and the horizontal tail is placed in front
of the wing; this arrangement is called the canard layout. The layout of the
Wright brothers’ aircraft is different from the aircraft that is often seen today.
If the horizontal tail is placed behind the wing, it is called the conventional
layout; if the horizontal tail is placed in front of the wing, it is the layout of
the Wright brothers, called the canard layout. The flight control principle of
these two layouts is different during flight. The flight stability of the conventional layout is better, so the civil aircraft uses this layout. The canard layout,
although poor in stability, has good maneuverability, so fighters often use
this layout. For example, the Chinese J-10 fighter placed the horizontal tail
in front of the wing. The tail that is placed in front is called the canard, and
the tail placed behind is called the horizontal tail.
The speed of the early aircraft was relatively small, so the first problem
encountered was the insufficient lift generated. How to generate a large
enough lift to fly the aircraft is the key to the early design and manufacture
of the aircraft. Since the aerodynamic force of the aircraft is proportional to
the square of the flight speed, when the flight speed is small, the aerodynamic force generated under the same wing area is also small, but the weight
of the aircraft cannot be reduced, so measures to increase the wing area are
taken. But considering the factors in the structure of the wing, the layout of
two-layer wing and even the three-layer wing appeared in the early aircraft.
The three-layer wing layout was created because the two-layer wing was not
enough, so the three-layer was created (as shown in Fig. 7.35). Because the
flight speed is relatively small, the drag is not highlighted compared to the
lift.
According to the definition of Langley et al., the lift expression of the
aircraft is
L =
1
2
ρV
2
∞ C L S
V ∞ is the inflow velocity (the flying speed of the aircraft), S is the characteristic area of the wing, C L is the lift coefficient of the wing. The drag
expression is
D =
1
2
ρV
2
∞ C D S
where D is drag of the wing (parallel to the direction of flow), C D is the drag
coefficient of the wing.