Monday, 19 August 2013

Basic aerodynamics or why does it hang in the air?

As all of us know that Newton law universal gravitation works on everyone of us. So how does airplane, weighting tens of tones does not fall from the sky like stone? And how it gets so high in the first place? Well, there is simple aerodynamics in place:

1) every airplane has mass and gravity force attracts it to the Air;
2) in order to hang in the air, this force must be eliminated by the same magnitude, but opposite direction force. In airplane this force is generated by wings (Lift force);
3) in order for wings to generate Lift force, it needs to be blown over with high speed air. How to get high speed air? Just move with high speed relative to the air. E.g. move quickly forward.
4) when airplane moves with high speed it generates not only Lift force from the wings, but traction on airplane surface generates Drag force. Because of this force airplane must constantly battle with it and use engine power to maintain forward speed.

That is it. There is no wishing or undefined part in equation why plane flies. So whenever plane has enough forward speed and appropriate to its weight wings, it will fly. Did you know - there practically can not be such big force applied to wing during the flight that could break wings off.
Why? Wings are made to be elastic and move a bit during turbulence, and they are constructed so, that they can hold more than double theoretical forces encountered by wing during the flight. This calculated force is always applied during wing testing before manufacturing any plane (wings are literally bend from the tips till they break).

There is simple experiment to feel that Lift force by yourself. While driving in car, just (CAREFULLY) extend your arm through window, palm facing downwards. Then just slightly rise front part of palm. You will feel Lift force, that is the same as Lift force generated by wings. Just they has much much much bigger area, so they generate much much much more Lift force, that can even lift whole airplane.

So for every airplane critical is air speed (not ground speed, as airplane during flight "sits" on air, and not ground, so wind speed is what it needs). By the way, because of that, every airplane takes-off and lands against the wind - so even ant 0 ground speed, the air speed is already more than 0, and wings are already generating small amount of Lift.

Now you know, why airplane "hangs in the air". In my next posts I will be writing how exactly wings generate Lift force and how jet engines work.

See ya!

Saturday, 17 August 2013

Departure Hall, or Intro

"Aren't you afraid to fly?" - that was one of the most common questions I have heard when introducing myself to new acquaintances and mentioning, that at that time as was airline steward (for almost 6 years and on average 4 times a week). Most of the times, this question just made me smile, till one day, it dawned on me - there are people, that are afraid to fly! Genius, you would say, but at that time, flying was one of the best things in my life. How could other people do not like and even be afraid of it?

That's why I started talking more and more about it and found out, that statistically, 1 of 5 persons onboard are afraid (or at least are uncomfortable) to fly! Imagine Boeing 737 with 120 persons onboard. That means, that 24 persons are afraid. That means, first 4 rows (not literally) are afraid to fly.

After leaving airline, I for a few years gathered data and researched why people have fear of flying and how to help them. It turned out, that there are just several reasons for that fear:

1) lack of knowledge how airplane and whole airline business operates ("how can airplane weighting tens of tones hang in the air?", "what if pilot is drunk?", "what if mechanic forgot to tighten that bolt?", "what is that sound, noise?", "after take off I feel that sound of airplane changes and it seems like we are falling", and so on and so forth). This we will address with topics on aviation industry and airplanes.

2) Past bad experience (own, friend's or seen on TV) like turbulence, bad landings, crashes. And it really does not matter if it happened to you or not - our subconscious can not differentiate if the event happened for real or not IF WE BELIEVE IN IT (that is why autosuggestion works). This could be addressed by special relaxation exercises, NLP and consciously moving your attention to other things than flight (books, movies, music)

3) combination of 1) and 2). This is why I can not watch movies about airplanes. There are so much crap and bulls**t in it, that it literally makes me mad. For example movie "LOST". Good movie, one of my favourites, except 1 episode, where they "crash land" on island and there are parts of airplane all over the beach and ONE ENGINE IS STILL RUNNING! How??  Where it takes fuel from? Ignition? How all electronics are working? Crap… And of course it explodes, to make better impact for viewer. In real world almost everything that you will see in movies regarding problems in airplane are invented to make it "more interesting" or "make impact". During normal flight you will never see hole in fuselage through it stewardess could be sucked out, or turbulence that rips planes wings off (I will put visual evidence of that in later posts), pilots flying airplanes, that they are nor familiar of and that has not passed tests... (rules in aviation are so strict, that if it would be implemented into everyday people life, you could not borrow your car from spouse or friend, before that not taking exam on the differences of the your car and this new car, without taking driving exam with instructor and without medical examination..).

Thats why my course "Flying without fear" was born. It was first one in Baltic States, and we had quite a success with it. Now I would like to share it with you. I will post topics discussed in my course and make examples from real life. Hope you will enjoy it and if not completely eliminate your fear, then at least you will be able to take that next flight without medications and alcohol (the worst kind of "fear elimination" that you could find on Earth).

So welcome onboard and take your seats. Prepare for wonderful journey into aviation world.