3.3 Supplementary Reading texts Aircraft – General

ICAO defines an aircraft as “any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of air against the earth’s surface”

Probably the best place for us to start is with a general description of an aircraft.

An aircraft is comprised of:

1. Airframe

2. Powerplant

3. Systems

4. Equipment

1. The airframe is made up of a fuselage, wings and tail plane. This structure is supported on the ground by the undercarriage which is generally raised and lowered by hydraulic power. In flight it is supported by the wings.

2. The powerplant on an aircraft is usually either piston, turboprop or turbojet. Fuel for a piston engine aircraft is petrol, while that for turboprop or turbojet is kerosene.

3. The main systems on modern aircraft are air conditioning, automatic flight, electrics, flight controls, fuel, hydraulics, landing gear, pneumatics, powerplant and pressurization. Each system has an ATA reference number.

4. Equipment consists of various items such as passengers seats, galleys, radios, computers, fire extinguishers, toilets, etc.

Answer the questions.

1. What is an aircraft comprised of?

2. What is airframe made up of?

3. What types of the power plant are these on the aircraft?

4. What are the main systems on modern aircraft?

5. What does equipment consist of?

Vertical and Short take-off and Landing Aircraft

Modern airplanes become heavier and faster. They need more complex and longer runways. Airports are rapidly developing and swallow up more and more precious land. That is why so much research is going into the development of short take-off and landing and vertical take-off and landing aircraft (STOL and VTOL). Most modern planes have thrust reversers which make their engines blow the other way. When the plane lands, the pilot operates a lever and special doors close and block off the normal exit for the exhaust gases, uncovering at the same time the thrust reverser ducts. The exhaust gases are deflected forwards and effectively slow down the plane.

In a VTOL aircraft the deflector nozzles of the gas turbine engine can be rotated to point either downwards for vertical lift, or to the rear for normal forward propulsion. To increase stability and lift during take-off and landing stages of the flight, the VTOL aircraft have two more nozzles near the front of the engine, which expel gases from additional or plenum, combustion chambers. Almost all modern VTOL aircraft operate on this principle of plenum chamber burning (PCB). The VTOL aircraft feature low fuel efficiency and high level of noise.

There are other VTOL projects which attempt to solve the problem in a different way. Some feature lift-fan engines built into the wingtips of the aircraft. Other projects use whole engines that swivel to give either vertical or horizontal thrust. Many outstanding aircraft designers are working on new R&D programs in the field of STOL and VTOL aircraft.

Answer the questions.

1. How does a thrust reverser operate?

2. Why is so much research going into the development of STOL and VTOL aircraft?

3. Why do modern runways become more complex and longer?

4. What happens when the pilot operates the thrust reverser lever?

5. What are the two nozzles near the front of the VTOL engine for?

6. What does the principle of PCB come to?

7. What drawbacks are common to all VTOL aircraft?

8. In what other ways can the VTOL problem be solved?