AERONAUTICAL LECTURING NOTES

Explain the vapor cycle cooling system used in aircraft with neat illustration. Also explain the physics behind the scene of working. Physical principle Liquids can be vaporized at any temperature by changing the pressure acting on it.  To clearly understand this concept, we will take an example of water contained in a vessel. When the vessel is at atmospheric pressure, the water will be boiling at 100°C when heating. If I am pressurizing the vessel to more than the atmospheric pressure, then water will not boil at 100°C. If I am creating a drop in pressure in the vessel by a vacuum pump, then water will boil at a temperature less than 100°C. Basic law of thermodynamics states that heat will always flow from hot body to cold body. If I need a reverse of this, I have to add some work. System operation: 1. We are having the FREON as refrigerant in the vapor cycle cooling system. It has a boiling point of 4°C. 2. At the receiver I am having high pressure, ...

Why we need aircraft's cabin pressure and temperature to be controlled? At atmospheric condition we have sufficient pressure to breath freely. As the altitude increases pressure drops. Till 8,000 ft altitude the pressure variation won’t affect us but beyond that we will get affect (hypoxia), so in order to have same pressure to breath freely in the cabin of aircraft, we need to go for maintaining the pressure artificially. As like pressure temperature also drops as the altitude increases, but up to certain layer of atmosphere which is stratosphere. Most of the aircraft are operating within Stratosphere. So we need to have a constant temperature in our cabin, so that passengers feel the comfort of their travel.  What are the methods in practice for maintaining cabin pressure and temperature? Air cycle system Vapor cycle system Explain Air cycle cooling system of cabin atmosphere control with neat figure? .      Left engine ...

What are the methods to find smoke prevailing in aircraft? Explain with neat sketches. For smoke, fire is main reason. In some cases it may not be. However pure air just contains 78% of nitrogen, 21% of oxygen and 1% rest of other gases. When there is fire in the aircraft the air will be dirt since carbon monoxide or carbon dioxide presents. There are four effective ways to identify the smoke. Light detection Light Refraction Ionization Solid state semiconductor Light detection type: We all know photo voltaic cell converts light energy into electrical energy. The pure light rays will be fall on photo voltaic panel and produces some electrical energy at normal.  When the area is surrounded by smoke the intensity of light rays falling on the panel gets differ. From that we get alarm. Light Refraction type smoke detector: Here a certain mass of air is taken for smoke detection by use of fan. Source of light is the Electric bulb. It is made to ...