Wednesday, 30 April 2014

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.

Tuesday, 8 April 2014

What is a Supersonic Aircraft ?

SuperSonic Aircrafts

Living 2 miles north from the Runway 36L at Heathrow Airport is more than an ear shattering experience. Everyday you wake up to the sounds of rotary internal combustion engines bustling through the air as they prepare for their climb out of LHR and into the skies.

As the last flight just nozzles over the roof of your house, and touches down it's been a more than fascinating experience as you cherish the progression of what technology has evolved into, well atleast an enthusiast like me does. Isn't it incredible to even think that just to translate the concept of seeing a bird with two wings, into a fully functional machine which allows us to cross continents in a matter of hours, or even minutes if we consider hypersonic models.

Being in the flightpath of Heathrow, has always see different aircraft take off and land, and from there on my enthusiasm for Aviation has grown day by day. I'd like to share some of the experiences and technical sides of one of my more favourite types of aircraft - Supersonic aircraft.

Essentially superonic means greater than the speed of sound. If we were to express this in normal terms, this means anything higher than 768 mph, given the temperature is 20 degrees centigrade in dry air conditions at sea level (0 ft.). Why is this particular amazing ?

768 mph is only the minimum speed to be Supersonic. Supersonic Aircraft are extremely swift !! The only commercial airliners that's flown at Supersonic Speeds is the Concorde and the Tupolev Tu-160, which served transatlantic routes in 3 hours !! After the sad end of the Concorde era, there's been no commercial plane that's flown at Supersonic speeds for the public.

I'd really hope that in the near future, the idea of operating Supersonic aircraft bcomes viable again. This will open up real opportunities for young innovators in Science to design elements of Aircraft that can help planes be speedy, yet safe and secure. With business being a global connection between all countries, there would always be demand for people to cross countries within hours, and then be back home by the evening. I will introduce some technical jargon related to aviation and physics needed to understand Supersonic aircraft.