Aircraft into Space?

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Aircraft into Space?



Aircraft into Space?

In my previous post, I mentioned that escape velocity is the maximum velocity of aircraft within earth's atmosphere. Escape velocity is minimum velocity required for any object to leave planet's atmosphere. On our earth 11.2 Kmps or 32 mach is escape velocity for any object.




When aircraft flies, its the earth's gravitational pull which keeps aircraft in earth's atmosphere. So aircraft can't go straight into space. Earth's gravity will pull aircraft into circular path as aircraft don't have much energy to escape from gravitational pull. So if we provide our aircraft energy to escape from earth's gravity our aircraft will leave earth's atmosphere. So we provide aircraft this energy in terms of kinetic energy.

Kinetic Energy= 1/2(mv^2)
M= mass of aircraft
V= Velocity of aircraft

Gravitational potential energy to leave earth's gravity= (Gm)/R - 0
G= Universal gravitational Constant
m= mass of earth
R= distance of aircraft from earth's centre.

(Gm/R is gravitational potential energy on earth's surface, 0 is gravitational potential energy at infinity (here, at infinity R becomes infinity so (Gm)/R becomes zero)

So, we will provide same energy to our aircraft which any object will have at infinite distance from earth.

Hence,

1/2(mv^2) = (Gm)/R

So, velocity becomes

V= sqrt[(2Gm)/r]

So here, V is known as escape velocity which any object should have to  leave earth's atmosphere.
For earth it is 11.2Kmps or 32 Mach.

At such a high speed it is not possible to keep aircraft in earth's atmosphere. So what if we tried to keep aircraft in earth's atmosphere by turning aircraft nose down?




At present we use elevator to turn aircraft nose up & down.  if we use  elevator to turn aircraft nose down air impact will produce massive force of more than 11200N on elevator which will probably break elevator. Suppose if we make very strong elevator which can withstand such a massive force then is it possible to stay in earth's atmosphere at speed of escape velocity?
My answer is No!!
Because suppose aircraft is flying with speed exactly equal to speed of escape velocity & if we turn down aircraft nose using  elevator it will produce resistance to airflow & reduce speed of aircraft less than escape velocity.
If speed of  aircraft is little bit equal to or greater than escape velocity then aircraft will leave earth's atmosphere!!



Conclusion:- Escape velocity is maximum velocity of aircraft on earth!!!


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