Archive for the 'Airplanes' Category
Full throttle and downhill
I always thought that downhill was for bikes, maybe a buggy could do that as well. These two guys decided to do that…with an airplane. In fact, they get the Highlander, an amateur-built STOL aircraft that can actually land in less than 150 feet (50 meters) and in steep runways up to 40º. Amazing.
There’s no doubt they from USA, not only for the accent, but also for the country-like music they listen to when flying.
This vid has been recorded from another hill, from the outside, so you can appreciate much better the acrobatics.
This vid instead, show you the acrobatics onboard the airplane.
Extract from LandingShort.com
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Air France A380 back to JFK due to computer trouble
The recently unveiled Air France A380 that was flying from New York Kennedy Airport (KJFK) to Paris (LFPG) was forced to land back to New York, just 90 minutes after it took off. It is said that a minor computer problem could make that happens.
“It was Friday 30th at night. After 90 minutes of normal flight, the airplane was obliged to go back to the departure airport, New York Kennedy. The airplane is brand new, and it’s breaking in. The minor computer trouble caused some lost of accuracy on navigation parameters” an Air France spokesman said.
Air France A380
The Air France A380, the largest double-decker ever, lift his flight a week ago (Friday 20th) from Paris Roissy-Charles de Gaulle to New York – J.F. Kennedy with more than 500 passengers onboard.
No commentsThe Blues
The US Navy Flight Demonstration Squadron, also known as Blue Angels, is an aerobatic team from the US Navy. Every year, they perform in more than 70 shows around the States. Their birds, the F/A-18 Hornet, is one of the most emblematic aircraft, maybe much more emblematic than the Boeing 747.
The Blue Angels were born in 1946, and the main aim of this Squadron is to enhance the US Navy recruitment, trying to excite young people to enroll the Navy. And they certainly do.
Some of their tricks are the half-Cuban 8 takeoff, the knife-edge pass, the section high alpha or the Delta formation. If you want more info about them, just go to their official website.
And now, check this video out, with Van Halen as Blue Angels soundtrack. Awesome.
And here you have the Fat Albert (Hercules C-130) with a Jet Assisted Takeoff.
Fly-by-wire and Airbus Laws
Nowadays, commercial airplanes do not fly with metal wires moving the ailerons anymore. Now it is managed digitally, from the source (the sidestick or yoke movements) to the control surfaces movement. This system is called Fly-by-wire.
The fly-by-wire system consists of some computers (5 computers on board the Airbus’ planes, 3 primary and 2 secondary), that read the pilot movements, interpret them, and it sends a modified signal (from the original one) to the control surfaces.
All these means that the airplane movements will not match proportionally what the pilot is doing actually. This philosophy shocked a lot of pilots, they couldn’t imagine flying something without a cable between the yoke and the surfaces. Finally, it was demonstrated that this system was much efficient, safer and much versatile.
Airbus was the first one using fully fly-by-wire (A320 were the first) and they create a set of laws that would govern this system. There are 4 laws: normal law, alternate law, direct law and mechanical back-up depending on the degradation of the airplane.
- Normal Law: It is on when normal operation is carried out. It controls the 3 axis (pitch, roll and yaw) balancing the aircraft and interpreting the sidestick movements. In addition, it offers some envelope flight protections (on pitch attitude and roll attitude) and alleviate load factors, like the gravity when turning for a much better comfort.
- Alternate Law: If a minor failure exists (sensors disagreement, computer blackout, hydraulic system upset,etc) this law becomes the active one. Basically it provides the same control as the normal law, but without protections. Also, the roll control becomes “direct law-like” control.
- Direct Law: If a major failure exists (radio altimeter failure when approaching, 3 inertial references down, etc) this law become the active one. Then, the movements of the control surfaces are the same as the sidestick movements. There is no auto trim, and any protection system will be available (even alpha-floor for stall warning).
- Mechanical Back-up: This mechanical aid should be used when the electrical system is all down. Then, the airplane can only be controlled with the trim wheel for pitching, and rudder pedals for rolling.
The SELCAL Code
The SELCAL system or Selective Calling system, commonly used in aeronautical communications, is a multiple system that allows the radio ground-based operator to send a signal to the aircraft that wants to establish a communication. In other words, when an ATC want to talk with an airplane flying over the ocean, he pushes a button and the airplane’s crew receive a message. That is kind of worthy in oceanic routes, where HF (High Frequency) communications give a lot of background noise, and pilots usually turn off the squelch until they receive this signal.
In order to identify each single aircraft, a SELCAL code is assigned to each one. This code is made by 2 pairs of letters (using from “A” to “S” excluding “I” and “O”) and each letter has an assigned frequency. Then, when the operator wants to talk with that aircraft, a 4-tone signal is sent with those letters. Everybody who is in that frequency will hear that sound, but only the one with that code will receive a sound alert (bling-blong-like sound) and a light alert.
There are 10920 different SELCAL codes. That’s the reason why there are duplicate codes (two airplanes, same code). Only airplanes operating oceanic routes use that system though. So, when a duplicate code exists, they make certain that those airplanes will operate in widely separate parts of the world.
ARINC (Aeronautical Radio Inc.) issues these codes in the US. You can find real-world SELCAL codes in this website just entering the registration number.
5 commentsWake Turbulence: Pilots’ Nightmare
Each conventional aircraft, just because they have wings, they create wake turbulences at wing tips. Since we have high pressure underneath the wing and low pressure above it, this pressure difference converge at the wing tips. Air from high pressure goes up to low pressure zones, plus the forward movement of the airplane create an espiral-like movement of rough air behind the airplane. These wake turbulences are increased (abruptness and size) when dealing with heavy airplanes and low speeds, like the approach stage.
Wake turbulence created by the airplane (NASA)
This rough air does not concern this aircraft, but the aircraft behind it does. Actually, the aircraft behind might fly through this turbulence. As the air is in rotation, it does not keep sticked to the wing foil, so it may cause a lift loss. That’s why ICAO establishes a minimum separation between aircrafts, enroute as well as in approach, in order to avoid rough air. These turbulences drive away because of air viscosity and because of the wind. Even that, they could be 5 miles long and go down up to 900 ft.
In order to decrease these effects, there is a very used and useful tool called winglet, set up at the wing tip, and it slows down the air flow reducing then, the wake turbulence (and the fuel consumption).
