**2.3 Flight Mach number**

At low flight speeds, compressibility of air may be neglected (ρ assumed constant), but as the flight speed increases, air gets compressed, and change in ρ cannot be neglected. Above M > 0.3 (M = Mach number; defined as the ratio of aircraft speed and speed of sound, named after Austrian Physicist Ernst Mach), compressibility effect cannot be neglected. The solution of a three-dimensional flow with air viscosity terms included at higher speed thus becomes complex.

Depending on the flow M, the aerodynamic studies are classified as:


**7**

*Military Aviation Principles*

**3. Military aircraft**

**3.1 Combat aircraft**

JAS 39 Gripen, etc.

include the following [1, 3, 5].

*3.1.1 Fighters (air superiority, interceptor and fighter)*

applications.

*DOI: http://dx.doi.org/10.5772/intechopen.87087*

use equations from gas dynamics.

may be ionized and ideal gas equations may no more be applicable, and we may

Any aircraft that is operated by a legal or insurrectionary armed force may be called military aircraft. Military uses aircraft for both combat and noncombat

Combat aircraft are designed and developed for use by military to destroy enemy assets using on-board armaments/stores. Military aircraft and their applications

Fighters are meant to engage in air-to-air combat with enemy aircraft and outclass them. They are therefore light and have high speeds and manoeuverability. Fighters are used for both offensive and defensive roles. Interceptor is intended to be light and agile and has high acceleration and rate of climb to intercept an enemy aircraft spotted by the ground surveillance radar and engage in dogfight. The main weapons these aircraft carry are air-to-air combat missile and air gun. Many fighters have a secondary role of ground attack capabilities where it carries bombs and air-to-surface missiles (ASM).

A fighter's main purpose is to establish and maintain 'air superiority' which means it denies the air power of opposing air forces for effective interference. Since the early days of aerial combat, armed forces have constantly invested to develop technologically superior fighters and attain air supremacy over the adversaries. Substantial proportion of the defence budgets of modern armed forces is spent for these purposes. Some of the modern fighters include General Dynamics F-16 Fighting Falcon, Dassault Rafale, Dassault Mirage 2000, Russian Su-30MKI, Mikoyan MiG-29, Saab

This is how the concept of multirole combat aircraft (MRCA) has evolved.

*3.1.2 Bombers (bombers, strategic bombers, tactical bomber and interdictor)*

Tupolev TU-95, etc. are some of the present days' strategic bombers.

and military troop transport/supplies and supporting offensive operations. An interdictor is an attack aircraft designed to interrupt enemy supply operation by aerial bombing. A deep penetration aircraft is a version of interdictor having longer range and capabilities. The main purpose of these aircraft is to prevent or cause delays to enemy forces and supplies reaching the battlefront. Russian MiG-23BN/MiG-27, Dassault-Breguet Mirage 2000D and Panavia Tornado are some of the present-day bombers.

A bomber is a combat aircraft designed to attack ground and naval targets by dropping air-to-ground weapons like bombs (dumb and smart bombs); firing ASM, torpedoes and bullets; or deploying air-launched cruise missiles. Heavy bombers (known as strategic bombers) armed with powerful conventional or nuclear weapons are used for long-range bombing missions against strategic targets such as supply bases, bridges, factories, shipyards and cities and thus cripple the enemy infrastructure and capability to continue war or stage new attacks. B-2 Spirit, B-52,

Tactical bombers are smaller bombers with shorter range and weapon capability and used for battlefield tactical operations like countering enemy military activity

may be ionized and ideal gas equations may no more be applicable, and we may use equations from gas dynamics.
