Android Applications for Aircraft Maintenance Mechanics/Technicians/Engineers

Hi Everyone,
As android system is being popular day by day with free or pocket friendly applications, having millions of users, I thought it beneficial to share some cool must have apps for Aircraft Mechanics. I am adding some now, and will add more gradually.
Everyone is most welcome to suggest more apps and benefit others.

Magazines and Articles:

1. FAST by Airbus

Description (as on Google Play)
This free Airbus technical magazine stands for Flight, Airworthiness, Support and Technology. The articles are written by Airbus engineers, maintenance staff, pilots, instructors, upgrade services, etc. Its objective is to spread over the aviation community, airworthiness authorities, schools and universities, Airbus’ philosophy on technical, research & technology, maintenance and environmental matters, to name a few. The subjects vary from one edition to another for Airbus’ entire fleet.

Download FAST by Airbus

2. Aircraft Maintenance Technology

Description (as on Google Play)
Aircraft Maintenance Technology (AMT) magazine is written by aircraft maintenance professionals for the aircraft maintenance community. Editorial is focused on the latest technology and maintenance best practices from all segments of aviation and aircraft maintenance. Regular columns include Staying Legal, AMTSociety Mx Logs Update, and Industry Viewpoint. Special focus on tools is presented in the quarterly Tools & Equipment. AMT reaches more aircraft maintenance professionals than any other media with our print circulation and digital products including a weekly eNewsletter; quarterly webinars; and eMilitary Product News.

Download AMT Magazine

What is the Boundary Layer?

INTRO

In fluid dynamics, Boundary Layer is a THIN (less than an inch), SLOW MOVING (nearly zero velocity) layer of moving fluid which is in contact with the surface of any object (car, boat, aircraft, golf ball etc). It STICKS and tends to wrap around the object due to the VISCOSITY of the fluid.





Yes! You guessed it right ZERO VISCOSITY (ideal) means NO BOUNDARY LAYER!

Being Aircraft Mechanics we are naturally more concerned about Aircraft!
Let's see how Boundary Layer affects our airfoils and how we control it to change overall lift and controllability characteristics

AERODYNAMICS
When the free air stream comes into contact with the airfoil, the flow closer or in contact with the airfoil tends to slow down owing to it's viscosity and surface friction with the surface of the object. This thin layer of airflow is termed as the BOUNDARY LAYER. The boundary layer consists of several layers flowing over each other, each layer is a bit faster than the layer below it, hence there is a gradual increase in velocity from airfoil surface to the free stream (see Fig 1)

Figure 1 - Gradual Increase of Layer Velocity from Surface to the Free Stream


As the boundary layer is slow-moving in nature it has low Kinetic Energy. This lower energy results in it's separation from the airfoil (Fig 2).

Figure 2

NOTE: The static pressure increases from the thickest point of the airfoil to the trailing edge (See Fig 3), thus the boundary layer needs more energy to flow to the high pressure area or it will separate from the airfoil.

Figure 3

MORE KINETIC ENERGY means FARTHER SEPARATION POINT

Thus to delay the separation point, or to get the maximum positive effects from the airfoil (lift, controllability), we try to provide more energy the boundary layer.
To energize the boundary layer devices like SLOTS, VORTEX GENERATORS are used.


P.S. I have kept the post simple, there is much more to be added to this article, but this one is to give just some general concept of the Boundary Layer. You can always suggest improvements and help others!

What are Vortex Generators and What purpose do they serve?

There is a lot of information over the internet about the purpose of Vortex Generators. I will shed light on just some important notes you should keep in mind as an Aircraft Mechanic, I will try to explain more details later (if necessary) bu updating this post

Before proceeding I assume you are accustomed with the following terms:
Boundary Layer, Laminar/Turbulent Flow, Stall

VORTEX GENERATORS

Vortex Generators are small aerodynamic devices, generally fitted to the leading edge of wings (including ailerons, elevators etc).

The laminar flow tends to separate from the wing at some point (Transition Point) behind the leading edge, as the angle of attack increases the transition point moves forward, this can lead to a situation which will ultimately cause the wing to stall.

Transition Point - The point at which Laminar Flow leaves the airfoil causing a Turbulent Flow in result, so there is a transition from Laminar to Turbulent Flow at the Transition Point


HOW DO THEY WORK
The boundary layer of Laminar Flow is low in energy as compared to that of Turbulent Flow, thus to energize the boundary layer vortex generators are used.

Simple Operational Principle: As the name implies, when the airflow passes over the vortex generators they generate small vortices, these turbulent vortices energize the boundary layer and helps it stick with the airfoil surface thus delaying the formation of transition point/region.

Saw this interesting photo on a website www.aerospaceweb.org which can help you understand the phenomenon

Note: I tried to keep it short and simple. More information can be provided upon your request. Kindly suggest me updates for this article to make it better! 

Carbon Brakes or Metallic Brakes: What is the better choice?

Brief Intro:

Brakes are used to stop the Airplane (simple)
Operationally, the brakes convert the Kinetic Energy of the moving airplane to Heat Energy (that is why they are also known as Heat Packs) which is dissipated into the atmosphere by air flowing over the brake units.
Heat results in increased temperature, which directly impacts the life of braking unit.

METAL BRAKES

Steel pads are used between the Pressure and Backing Plates, when these plates are forced into each other the friction of the brakes cause the wheels to stop (this process in turn generates a lot of heat)

Steel Brakes are generally cheaper in price than their carbon counterparts and this was the primary reason they were being used.
But the problems with these brakes is their higher frequency of overhauls and also their heavy weights.

CARBON BRAKES

As it has been previously discussed that the brakes are kinetic to heat energy converters, thus their efficiency depends upon the amount of energy that can be absorbed by the brake.
In carbon brakes, the friction is produced by carbon fibre discs, which are capable of absorbing much more energy than the conventional metal brakes, thus they are more efficient in braking applications.
Other major advantage of the carbon brakes is they are much lighter as compared to metal brakes having same efficiency, this weight saving (of around 200-400 kg) is a of great advantage in terms of less fuel consumption. Less emission of CO2 by Engines is another by-product.
Carbon Brakes are more expensive than metal brakes yet they justify their cost by increased time between overhauls.

SUMMARY

Carbon Brakes are preferred on aircraft because following aspects:

1. Higher braking efficiency (greater energy absorption capability)
2. Weight saving (Fuel saving)
3. Less pollution (less emission of CO2 due to decreased fuel consumption)
4. More time between overhauls