The Wright Brothers Never Invented the Airplane--Part II

Friday, September 23, 2011

Yes, I know I owe you an update from last week, but my homework started to get the best of me so I needed to put this on hold temporarily, so I'll combine two weeks' class updates into one post.

I've always joked my end would be death by homework.  Now it's not so funny.  Well, okay, maybe it's just a little funny.

But not to me.  Okay, so I've laughed about it.

 Can we move on?

Did you know the Wright Brothers never really invented the airplane?  They get all the credit for doing so because they were savvy enough to get to the patent office first.  The actual inventor of the airplane was Glenn Curtis (unless you're a die-hard Brazilian and then it's Dumont).

Curtis was commissioned by Alexander Graham Bell to create an engine for a "heavier-than-air" machine, thanks to his stupendous reputation for inventing and working with machinery.  When the private pilots' licenses were issued, he received his first.  Orville Wright received license number five, because at that time, the licenses were issued in alphabetical order.  And then there was that whole Patent Office snafu that any idiot with a finger can Google.

I eagerly awaited last week's class.  I'd often wondered just how a ground school flight instructor would begin explaining such a complex machine.  How did one begin explaining how to navigate and manoeuvre an aircraft through three-dimensional space?  Thankfully, our cars operate on two axes in the Cartesian plane (that diagram you've seen of two lines that intersect):  x and y.  But now we suddenly have z with which to contend.  It almost seems like God gave the morons who can't drive an extra dimension in which to screw up.

 So we started the meat of the lecture with a basic diagram of a plane.  Seemed a likely place to start.  Then we immediately began discussing the aerodynamics.

There are four forces that act upon the aircraft:  Gravity (weight), Lift, Drag and Thrust.  Weight is pretty self-explanatory, especially to a woman.  Lift is the interesting one because it's created out of a combination of airfoil surfaces, thrust, and low/high-pressure spots on the wing.  Actually, lift is created out of a difference in pressure between these forces.  Drag is a difficult one to explain because why it occurs is very tricky (aside from the fact that there are many varying types of drag a pilot needs to know), and thrust is comprised of juicy things like the slipstream (the phenomenon of air created by a propeller that wraps around the body of the plane causing it to yaw), torque, another natural phenomenon that pushes the airplane to the left to counteract the yaw, load factors and finally the gyroscopic effect (the phenomenon that causes the plane to respond to a command 90% later than it's given).

NOW we were talking.  This was the physics' portion and I was in heaven.  Although my Russian flight instructor (who also happens to be my math advisor) goes so fast I'm certain there will be a lot of out-of-class study in order to grasp all of it.

Avro Vulcan Bomber
The angle of attack (AOA) is very important in flying because it affects the amount of lift that acts on the aircraft.  Most standard airfoils (wings) on modern planes have a general AOA of about fifteen percent to the relative wind.  This means the wings are angled at fifteen-degrees to the ground.  (Model airplanes, however, don't have camber wings, they have delta wings, much like most fighter jets, thus, they don't operate under the same laws of general aerodynamics). 

Flaps and ailerons are two control surfaces that deflect air flow and change the camber of the wing (camber, being the general curvature on top of the wing).  The only thing you use a flap for is to steepen your approach on landing.  Remember, I said from last week that a landing is a controlled crash (stall)?  This is why.  Reduce the amount of air flowing over the wing, and your airplane will be heading for a swift landing while you're still trying to see Sarah Palin's house in Russia.

And you've all heard of Bernoulli's Theorem where flight is concerned.  It's not magical or mystical, or even difficult.  It just states, in a nutshell, that the faster an object moves through a liquid (air), the lower the pressure it creates.  The Theorem was created for fluid dynamics, but one can think of air as a type of fluid which carries similar characteristics, thus the theorem can be applied to aerodynamics.

Fast forward to this week.

After learning the external forces that act on the aircraft, we then turned our attentions inward to the instruments.

Compass:  this points to magnetic north but the north on aviation charts is true north.  This produces a phenomenon known as the Turning Error, where the centre of gravity tilts south of the compass heading during a turn.  So you must compensate for it before the turn.  (Briefly, while we're on turning, it isn't the rudder that turns the plane.  The rudder simply tilts the plane, and the natural forces turn the plane.  Try this on your bicycle--you don't first turn your wheel to turn, you first lean into the turn.  It's the same idea.)

The compass suffers from something called Magnetic Deviation, meaning, other metallic objects in the cockpit affect its reading.

Air France Airbus A330
Does anyone remember that horrible Air France flight 447 jumbo jet accident in June 2009?  For the longest time, the BEA (the French version of our NTSB) was unable to determine what caused this Airbus A330 to simply fall out of the sky and crash, killing all 228 people on board.  In fact, the investigation is still on-going.  And it's now labeled as the worst aviation accident to occur since the American Airlines Flight 587 accident in 2001, and it was the first deadly accident to happen to an Airbus A330 while in passenger service.

Why?

The most apparent and largest cause was due to this next instrument:  the Pitot Tube.  In layman's terms, it's an airspeed indicator.  It's a small blade-like tube mounted on the outside of the aircraft.  The Altimeter and the Airspeed Indicator take their input from the Pitot Tube.  On this particular Air France Airbus, the Pitot Tubes had become iced over from lack of a working heating apparatus, thus giving inexact readings on the instruments in the cockpit.  The Pitot Tubes measure constant fluctuations in air-pressure readings, because that is what the instruments measure.  An altimeter is the best example of this, because it doesn't measure height off the ground, it measures the difference in air pressure from one altitude to another as compared to the air pressure on the ground; one reason a pilot must check the daily atmospheric pressure before take-off.

So, that was the gist of the lectures.  But I have a delicious surprise for you.  Next Saturday, October 1, I will be in the cockpit for my first flight lesson, and I will try to get live photos and maybe even some video for you.  This won't be my first flight lesson or first time flying a plane, but it will be for this excursion into my pilot's license.

And now, please place your seats in their upright position, grab your gear and deplane.  We'll see you next week, from the cockpit.

1 snarks:

Elizabeth said...

Beautiful photos.

NEW FOLLOWER

Elizabeth

http://silversolara.blogspot.com

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