Mach, Drag, Altitude, Wingspan - Aviation Jargon !

In this post I introduce you to some of the technical jargon that's common if you're reading about aircraft models, especially what I will talk about in my upcoming posts !

• Mach - Just another unit of Speed, but in terms of Sound. In mathematical context, it is the ratio of an aircraft's speed in relation to the speed of sound:

M = Velocity of Object / Speed of Sound.

Where M = Mach Number, Speed of Sound = 768 mph (if we presume the medium to be air).

Supersonic aircraft are aircaft which fly faster than Mach 1. Anything higher than Mach 5 is considered Hypersonic. Those beasts are usually unmanned (Imagine a pilot trying to control an aircraft going at like 2500 mph).

As Supersonic aircraft fly at faster speeds, the aerodynamics of them are completely seperate from transonic flights (normal commercial flights). Firstly their aerodynamic drag rises sharply, so to maintain speed one needs a design which can produce much greater engine power and a streamlined shape.

• Aerodynamic Drag - Let's break this word down - Aero means being in the "air". Drag means the force acting in the opposite direction relative to the motion of the object. So it basically is when an airplane is moving through the air, a force which acts in the opposite direction to it's movement, which results in a fall in velocity (speed).

Again we can quantify drag, by using the concept of a "drag coefficient", which indicates the level of drag an object will have, given it's surface area shape. So usually supersonic aircraft have to be streamlined, for them to have less drag force acting upon them.

• Wingspan -The wingspan of an aircraft is the distance from one wingtip to the other wingtip. A picture on the right, describes what the wingspan of an aircraft is measured, it is always measured in a straight line !

Learning the Flight dynamics, and the lift generated by the area of wingspan is quite a complicated but interesting topic. I won't dwelve into details here, as this isn't supposed to be a mechanics textbook, but more can be found here :

http://www.princeton.edu/~stengel/MAE331Lectures.html

• Altitude - The height reached by an aircraft. So "high the aircraft is flying", usually passenger jets have a cruising altitude (the point of the flight, where the airplane is not climbing, or descending) of around anywhere between 25,000 to 38,000 ft. Supersonic aircrafts have a higher cruising altitude.

In my next blogpost, I shall talk about the Bell X-1 which was developed by the Americans as an experimental plane powered by a thrust of 6000 Lb, this is the first recorded aircraft which flew at supersonic speeds.