An interesting picture from the past

Some days ago I heard that Sri Lanka's ministry of tourism is going to develop a village called Kalpitiya in the western cost of the island, as a new tourist destination. I tried to find more information. It is quite a nice place with many small islands, white sandy beaches and yea! dolphins. Looking forward to travel there and see how it looks like.

But the interesting picture I found is something else. It take us all the way back to the 2nd world war. I heard that Japanese bombed colombo that time. Then it was still Ceylon the british colony. Obviously they made it as a base for the war.
1941-44 St. Petersburg (Leningrad that time) being surrounded by Germans. Many things happened similarly through out the world.
And guess what happend in this neck of the woods during 40's! aha, Elephants were towing aircrafts . Good way of ground handling huh?

Now compare with the modern towing machine.

It's amazing how the world changed during the last century.
The article about the aircraft from Kalpitiya is below. More exactly the photograph was made in 1944:
"In April 1942 the island had been narrowly saved from invasion by gallantry of Canadian pilot Sqn. Ldr. Leonard Birchall who, flying a Catalina patrolling 250 miles south of Ceylon, sighted a huge Japanese invasion fleet. Under attack from Zero fighters he managed to radio the alarm before being shot down into the Indian Ocean. Alerted, the British forces withstood the heavy air and naval assaults that followed."

"As the British expanded operations on the island, the hastily built airstrip of HMS Rajaliya was carved out of dense jungle at Puttalam. The soft grass strip, reinforced with metal. Somerfield tracking, enabled the heavy American-built Chance Vought F4U Corsairs to use the runway, but during the monsoon season the Corsair’s tricky landing characteristics often sent them slithering off into the water-logged ground. It was then that the Navy called in its secret weapon to haul the Corsairs back to firmer ground – The Puttalam Elephants! Operating in conditions where towing tractors became quickly bogged down, the Puttalam Elephants provided an invaluable service, and became much loved by the pilots and ground crews."

Aircraft Visual Inspection

Figure: Boeing 777 aircraft Commercial aircrafts are frequently inspected visually. There is a primary inspection called "walk around check" both in the line and the base, transit checks, daily check, weekly check, A check, B check etc… Line is the more about the quick checks while aircraft is in the park or in between flights. Base is mostly the hanger, where hard checks, repairs take place. A qualified engineer walk around the aircraft and inspect structural items visually. Engine is also checked during the walk around checks. There engineer watches for oil leaks, structural damages in the engine, inlet of the engine for composite parts fixtures to the structure, fan/first stages of the compressor, last stages of the turbine for deterioration or damages , or any unusual changes of the engine. In this example shows how, engineer/Pilot carry on a walk around inspection of a Boeing 777 aircraft. Figure: Walk around inspection of a Boeing 777 1. Left Mid Fuselage

Eddy current method (ET)

Short research about the history of eddy current The first person to observe current eddies was François Arago (1786-1853), the 25 th president of France, Who was also a mathematician, physicist and astronomer.1824 He discovered what has been called rotatory magnetism, and the fact that most bodies could be magnetized; these discoveries were completed and explained by Michael Faraday (1791-1867). In 1834, Heinrich Lenz stated the principle that defines how the properties of the test objects are communicated back to the test system. Lenz's law states that the direction of current flow in the test object will be such that its magnetic field will oppose the magnetic field that caused the current flow in the test object. This means, in practice, the eddy currents communicate with the test coil by developing secondary flux that cancels a portion of the coil's flux equivalent to the magnitude and phase of the flux developed by the eddy currents. Léon Foucault (1819-1868) However,

Eddy current Theory

Eddy current theory is based on electromagnetic induction. That means, a variable magnetic field can induce an electric current on a conductor which is separate to the source of the magnetic field, and also vice versa, which is an electric current generates a magnetic field. Similar theory is used for the magnetic particles inspection as well. Electromagnetic induction is used in many applications such as, Transformers, Electric motors, Generators, etc... In the field of Non destructive testing (NDT), we manipulate with this theory which I mentioned above, and try to find surface defects or/and shallow internal defects of ferromagnetic materials.

Technical Diagnostics and NDT

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