Showing posts from July, 2018

Few Questions of Fluid Mechanics

1. What are the SI & CGS units of viscosity & kinematic viscosity? What is the relation between the SI & CGS
     unit of viscosity? What is the value of viscosity of air & water at 288 K temperature?

2. (a)Define bulk modulus of elasticity without using any formula?
    (b) Bulk modulus of elasticity of water is 2000000 kN/m2.  A pressure of 10 bar is applied on water having 
      volume of 2m3. Find the  change in volume of water in m3.
3. Find the flux of velocity having the components as 9x, -3y and 0 along the x, y and z axes respectively over      the closed surface of the sphere given by x2 + y2 + z2 = 9.
4.  A flow field is given by u = ay, v = bz & w =cx. Determine whether the flow is rotational or irrorational.
5. The clearance space between a shaft and a concentric sleeve has been filled with a Newtonian fluid. The     sleeve attains a speed of 600 mm/s when a force of 600N is applied to it parallel to the shaft. What force is     needed if it is desired to move…

Aerospace Engineering Students at Chandigarh University

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Why should the pilot fly a defective aircraft?

It is against common sense: 'Why should a pilot fly a defective aircraft and risk his and passengers' lives?'.

Both in the military as well as civil aviation, pilots are forced to fly defective aircraft. Many times pilots force the engineers and technicians to certify a defective aircraft as OK i.e. airworthy.
In Air Force/civil aviation, pilots do not like those engineers/technicians who say 'this aircraft is not OK. It cannot fly'. Pilots always want to hear,"Yes sir, everything is bang-on".
I say this from my experience/interaction over 3 decades of my life.
Many pilots are ambitious and want to clock as many flying hours as possible. They don't mind taking the risk. They just love flying and want to fly the aircraft at all costs. Very enthusiastic!
Many pilots are 'yes-men'. They want to please their bosses/management/ministers. Recently I met a Chief Pilot of Punjab Govt. He had the guts to tell the GOI Minister who was to fly," Sir,…