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Dec 26, 2010

LEDs - The Most Efficient Modern Man Made Light Source (35%)

They are now using LEDs everywhere and LEDs will replace most fluorescent lights in the future. Let's have a look what they can do.

BTW: Regardless of LED color, Cree advises users not to look directly at any LED lamp.

Here are a couple of videos.

Some LED safty factors:

"All light sources have the potential to be harmful to both the skin and the eyes through UV, blue light (410-480 nm) and IR emission. Independent photobiological testing of Cree visible light LED lamps has confrmed that the only health risk of visible light LED lamps signifcant enough to warrant advisory is viewing blue light with the eyes. LED lamps that emit blue light may be called multiple names, such as Blue, Royal Blue or Dental Blue. In addition, many white LED lamps, including Cree’s, are based on blue LED die and contain signifcant blue light content. Therefore, Cree has tested its Royal Blue, Blue and White LED lamps for eye safety.

Cree’s testing to date indicates that Royal Blue and Blue (450-485 nm dominant wavelength) LED lamps pose a higher eye safety hazard than White LED lamps. Other colors of LED lamps, such as Green or Red, do not pose a defned eye safety risk. Regardless of LED color, Cree advises users not to look directly at any LED lamp."

Cree® XLamp® XP Family LED

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Dec 18, 2010

Cockpit Mock-ups

Some links to wooden cockpit mock-ups:

Cockpit and Nose Mock-up

A wooden mock-up shell showing the electrical wiring of the Bombardier de Havilland Canada Dash 8 Q400 turboprop passenger plane.

70 percent P-39 cockpit and nosecone mock-up

The museum's Lancaster cockpit mock-up was on hand at the fly-in.

A wooden mock-up of Concorde was made at Filton in Bristol, 1963.

Dornier Do-X Wooden Moch-up

"Dornier Do-X design work began in 1924 in Altenrhein, Switzerland and nearly a quarter million man-hours were expended over the next five years before full size wooden mockup of the aircraft was completed."

"A new feature was the division into three decks. The cockpit, the navigation and radio room and the machinery room were located on the upper deck, while the main deck with its luxurious furnishings provided seating for up to 66 passengers. The lower deck was used to store fuel and supplies. For the first time in the history of aviation, a one-to-one wooden mock-up of an aircraft was built. For the construction of the Do X, a special assembly hangar with a slipway had to be erected, the site selected being Altenrhein on the Swiss shore of Lake Constance."

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Dec 17, 2010

Navigation Terminology

After now using MNS (Master Navigator Software) for several years it is time to learn all those abbreviations used in the navigation terminology. Cross Track Error or XTE is the key word for the quality of guidance. If you can keep XTE at it's minimum it is proven that you made the shortest distance from point to point.

Picture: Cross Track Error (XTE)

Here is a typical MNS guidance screen.

Picture: MNS En Route Guidance Screen  

XTE is shown on the right side blue window. At this moment we seem to be 898 meters left of the great circle between Nord and Npole (Nord and Npole are our waypoints) in this leg. When executing the route you should always keep XTE at it's minimum. The total leg distance is 920 km and it's true bearing is 0 degrees.

On the left side blue window you see several other parameters. Here they are explained:
  • WPT - Way point name
  • RTE - Route name
  • DST - Distance to way point or route end point
  • ETA - Estimated time of arrival to the way point or route end point
  • TTG - Time to go to the way point or route end point
  • VMC - Velocity made on course
  • CMG - Course made good
  • BRG - Bearing to the way point
  • LEG - Leg name
  • XTE - Cross track error (L/R = Left or right)
  • COG - Course over ground (Ground path direction)
  • HDG - Heading of the vehicle

Some more waypoint terminology in the following videos. MCDU stands for A320 Multifunction Control Display Unit.

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Dec 3, 2010

Airbus A380 High Lift Devices

An interesting video about A380 hi-lift devices. Notice that when using full flaps the small aileron becomes so inefficient that additional large span spoilers are needed. It is also interesting that the actual aileron is splitted to several parts and they seem to work sequentially: when one part is fully used the next part assists. The LAF (Load Alleviation Function) system must play a role here also.

Spoilers are sometimes called "lift dumpers". Spoilers that can be used asymmetrically are called spoilerons and are able to affect an aircraft's roll. For readers not familar with aircraft controls here is more basic information about it.

The flaps and slats are operated by long shafts and gear boxes from single motors located in the center of the fuselage as seen in the following picture. This is the noise heard in the videos.

SFCC stands for Slats & Flaps Control Computers.

Here is how the splitted aileron works and why it works as it does:

"The 380 has 3 ailerons per wing, an outer, mid, and inner, the inner aileron has an electrical back so the aircraft could be controlled even in the event of a total hydraulic failure.

For takeoff landing the ailerons deflect down a little, that is called the "Aileron Droop Function" (ADF), the objective of the ADF is to increase the high lift function performed by the slats and flaps. All the ailerons droop downwards (3 each side), when the flaps are extended. Ailerons and spoilers execute the roll function. Spoilers are needed at slow speed since ailerons only would be too unefficient for the roll function.

The ailerons also have another function called, "Load Alleviation Function" (LAF), the objective of the LAF is to reduce structure fatigue and static loads on the wing during manoeuvres and turbulence.Spoilers 6 to 8 and all the ailerons are involved in the LAF.

The LAF unloads the stresses on the wing by momentaraly deploying the flight spoilers and deflects ALL ailerons upward. The function is so fast that it is hardly noticable. I do not think that it makes the turbulance feel any worse though. The function seems to work very well.

These functions (apart from the electrical backup) are common on other Airbus types."

Some additional Airbus flight control documents (pdf format):

A380 Flight Controls Overview

Airbus flight control system

Airbus A330/A340 Flight Control System

Airbus Digital Electrical Flight Control System

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