flight school

Minggu, 29 Agustus 2010

Aircraft Pressurized System

1. Pressurized cabin atmosphera control.
    *suatu system yang mengatur udara di dalam cabin,sehingga layak bagi manusia untuk hidup selama penerbangan
2. Control
-Pressure
-Temperature
-Humidity

3. Makluk hidup (manusia) :
-membutuhkan O2 (oksigen)dalam kadar tertentu secara alamai -+ 21%
-terjdai pada sea level
-pressure 3 psi

4. Manusia normal hidup pada ketinggian ;8000 feet pada ketinggian 15000 feet kan terjadi HIPOXIA antara lain : ngantuk, pusing, pandangan kaberu dan sebagai_na
5. Keuntungan pressurized system pada pesawat
 -fuel consumption bakal berkurang
 - dapatmengindari cuaca buruk dan trumbulance
6. Permasalalahan:
 -  Disain srructure :harus kuat
 - Material
 - Pressure atmosfer : 14,7 psi 29,91 in Hg atau 1013 2 Milibar
7. pressurized system dan airconditioning <AC>
 -system heating
 -system cooling
8. macam_na;
 -air cycle system
 -gas cooling system
 -vapoop cycle system
9. Basic Requirement
a. sumber udara bertekanan:
 - engine driven compressor
 - indenpendent cabin super charge
 - air bleed
b.controlling cabinpressure ( out flow valve)

Type or gas turbine engines

Schematic of an aircraft jet engine.





Types of gas turbine engines.     Jet Engines

Jet engines operate on the application of Newton's third law of motion: for every action there is an equal and opposite reaction.

The most common type of jet engine is the turbojet engine. Air from the atmosphere enters the fan section at the front of the engine where it is compressed in the compressor section. Then it is forced into combustion chambers where fuel is sprayed into it and ignited. Gases that form expand rapidly and are exhausted out the rear of the combustion chambers. The energy from these gases spins the fan-like set of blades called a turbine, which rotates the turbine shaft. This shaft, in turn, rotates the compressor, thereby bringing in a fresh supply of air through the intake at the front of the engine. The rest of the energy is expelled out the tail pipe, providing forward thrust.

Adding an afterburner section, where extra fuel is sprayed into the gases as they are exhausted and the fuel burns, adds thrust.

In a turboprop engine, the exhaust gases rotate a propeller that is attached to the turbine shaft. The propeller provides increased fuel economy at lower altitudes.

Another type of turbine engine, called a turbofan or bypass engine, uses a fan to produce additional thrust. This is most efficient at high altitudes.

The fourth type of jet engine is the ramjet. The ramjet is a simple engine that lacks a turbine and compression chambers. Ramjets do not function at speeds below the speed of sound, although there are new variations of these called SCRAMjets that are designed to generate supersonic speeds. The engine must be on an aircraft already traveling above the speed of sound (supersonic speed) before it can be used. Supersonic air enters the front of the ramjet and is automatically compressed due to the shape of the engine's opening. This compressed air is mixed with fuel in the combustion chamber and ignited, causing the resulting gases and energy to be expelled out of the back and providing forward thrust.

A rocket engine operates on the same principle as a jet engine but carries its oxygen with it rather than using oxygen from the atmosphere.