1. Match the beginnings and the endings of the sentences.

1. In order to provide the necessary a) along the upper side of the aft

stability … portion of the fuselage body.

2. The dynamic balancing is one b) he moves the rudder to the right.

of the precautions taken….

3. Directional control of the airplane c) to produce constant control

is achieved …. deflections.

4. The structure of the tail unit d) airplanes are fitted with a tail consists of unit.

5. A movable control surface e) this is done by means of the

called an elevator is … elevator.

6. When the pilot needs to change f) to avoid flutter, a violent

his flight direction to the right… vibration of a wing or control surface.

7. Dorsal fin is placed … g) by means of the rudder, which is a movable vertical surface.

8. Balance areas reduce the hinge h) to right or left or retained in the

moment neutral position in line with the fin.

9. Trimmers represent small adjustable i) hinged to the rear of the

areas arranged … stabilizer.

10. If the pilot needs to cause the nose j) needed to deflect surface.

to rise or fall ….

11. Trimmers are used …. k) longitudinal and transverse

structural elements called

spars and ribs.

12. Rudder is hinged to the rear of l) near the trailing edges of the

the fin and can be moved … movable surfaces.

2. Translate in a written form matching with the picture.

In aircraft, a V-tail (sometimes called a "butterfly tail") is an unconventional arrangement of the tail control surfaces that replaces the traditional fin and horizontal surfaces with two surfaces set in a V-shaped configuration when viewed from the front or rear of the aircraft. The rear of each surface is hinged, and these movable sections combine the tasks of the elevators and rudder. The V-tail has not been a popular choice for aircraft manufacturers.

With fewer surfaces than a conventional tail, the V-tail is lighter and produces less drag. The air flowing over the tail surfaces is also likely to be less turbulent. A V-tail tends to reflect radar at an angle that reduces the return signal, making the aircraft harder to detect. This is an advantage for military aircraft.

Combining the pitch and yaw controls is difficult and requires a more complex control system. The V-tail arrangement also places greater stress on the rear fuselage when pitching and yawing.

In aircraft a T-tail is an arrangement of the tail control surfaces with the horizontal surfaces (tailplane and elevators) mounted to the top of the fin, rather than the more common location on the fuselage at the base of the fin. The resulting arrangement looks like a T when viewed from the front or back.

There are pros and cons to this arrangement.

The tailplane surfaces are kept well out of the airflow behind the wing, giving smoother flow, more predictable design characteristics.

The effective distance between wing and tailplane can be increased without a significant increase in the weight of the aircraft.

The tail surfaces are mounted well out of the way of the rear fuselage, permitting this site to be used for the aircraft's engines. This is why the T-tail arrangement is also commonly found on airliners with rear-mounted engines.

The fin must be made considerably stronger and stiffer to support the forces generated by the tailplane. Unless expensive composite materials are used, this inevitably makes it heavier as well.

Speaking

1. Work in groups. You are involved in developing of a new airplane. You are responsible for the tail group. Find out some additional information for your topic.

UNIT 9