Boeing 777 Stick Shaker and Fuel Dumping
When an airplane slows down too much, the stick shaker would come in. This is a stick shaker on a United 777 during a test. Testing on the fuel dumping system is also included. PBS owns the footage shown.
Airbus A380 Flutter Test
Flutter Excitation
One of the most dangerous events that can occur in flight is a phenomena called "flutter". Flutter is an aerodynamically induced vibration of a wing, tail, or control surface that can result in total structural failure in a matter of seconds. The prediction of flutter is not a precise science and requires flight verification that flutter will not occur within the normal flight envelope.
The aerodynamic surfaces of an airplane are constructed so that they can carry the loads that are produced in flight. For example the wing must be capable of supporting the weight of the airplane as well as the additional lift produced during turning flight. The resulting wing structure can be viewed as a blade or spring extending from the fuselage. If we "tap" the spring with a hammer, it will vibrate at a frequency which relates to the stiffness of the spring. A stiff spring will vibrate at a higher frequency than a more limber spring. This frequency is known as the "natural frequency" of the spring.
Flutter will usually occur at or near the natural frequency of the structure, that is, some small aerodynamic force will cause the structure to vibrate at its natural frequency. If this small force persists at the same frequency as the natural frequency of the structure, a condition called "resonance" occurs. Under a resonant condition, the amplitude of the vibration will increase dramatically in a very short time and can cause catastrophic failure in the structure.
The aerodynamic forces which can induce flutter are related to the dynamic pressure, or airspeed, of the airplane. If flutter-inducing forces are present they will increase as the airspeed is increased. Flutter characteristics can be explored by "tapping" the surface at progressively faster airspeeds, then watching how fast the vibrations decay or damp out. The vibrations will take longer to decay as the airspeed approaches a possible resonant condition. In this way potential flutter can be approached safely without actually reaching the resonant condition and experiencing sustained flutter.
The method for "tapping" the surface varies. On some airplanes a sharp control pulse is sufficient to excite the natural frequency of the surface. In most cases a special flutter excitation device is installed. This device will use either an aerodynamic vane or an unbalanced mass which is driven back and forth at the known natural frequency of the surface. The device is abruptly turned off and the natural damping characteristics of the vibrating surface are revealed. The analysis is similar to the frequency and damping analysis discussed under the "control pulse" maneuver, except that the structural (or flutter) frequencies are much higher.
Boeing 777 tailstrike (VMU Test)
The VMU Test performed on the 777-200. Sorry about the monents of weard soundings. This video is over 10 years old. PBS owns the footage shown.
Airbus A380 Tail Strike Test [VMU Test]
Tailstrike is an aviation term that describes an event in which the rear end of an aircraft touches (strikes) the runway. This can happen during takeoff of a fixed-wing aircraft if the pilot pulls up too rapidly, leading to the rear end of the fuselage touching the runway. It can also occur during landing if the pilot flares too aggressively. This is often the result of an attempt to land nearer to the runway threshold.
A tailstrike is physically possible only on an aircraft with tricycle landing gear; with a tail dragger configuration, the tail is already on the ground. Some delta wing aircraft, which require a high angle of attack on takeoff, are fitted with small tailwheels to prevent tailstrikes. Examples include the Concorde and Saab Draken. Some aircraft, such as the Diamond Aircraft Industries Diamond DA20, have a permanent skid installed to protect the airframe in the event of a tailstrike. Others may be fitted with a temporary skid as tailstrikes are sometimes purposefully carried out during the certification of new aircraft.
Tailstrike incidents rarely cause significant damage or cause danger, but may cause financial losses as the planes have to be thoroughly inspected and repaired.
However, improper repair to the damaged airframe after tailstrikes accidents may be responsible for fatal accidents that occur years later (including the worst single-aircraft accident as of 2008, the accident involving the Japan Airlines Flight 123) due to structural failure of the airframe at the site of the tailstrike after repeated cycles of pressurization and depressurization at the weak point of improper repair.
Boeing 787 Dreamliner test bed
When the first Boeing 787 Dreamliner will be unveiled on Sunday, July 8 at its official Premiere in Seattle, it will roll out with two next generation Rolls-Royce Trent 1000 engines - the leading powerplant for all versions of the 787. The Trent 1000's design has been focused on delivering world-best levels of fuel burn, noise and emissions. With its next generation technology and Trent pedigree, the Trent 1000 will deliver the lowest fuel burn economics over the life of the engine. Rig and engine testing have produced excellent results, and continuing introduction of new technology will ensure that the Trent 1000 delivers the lowest emissions for the 787, with significant margin to current and future legislation. With the largest fan on the 787, the Trent 1000 will also be the quietest. The Trent 1000 will also power the aircraft on its maiden flight later this year and will be the first to enter service with launch customer ANA (All Nippon Airways) in 2008.
Boeing 777 RR Trent 895-17 High Power Ground Run - LOUD !!!
After maintenance on the engine fuel systems, like changing the Low Pressure fuel filter and pressure testing the fuel feed manifold, it is necessary to perform a high power ground run of the engines to ensure a good fuel flow rate is maintained.
After the test the engines are opened and inspected for fuel and oil leaks, as some oil filters will have been changed as well.
The engines are brought up to high power, about 3/4 throttle to an Engine Pressure Ratio (EPR) of 1.4 or so. The other engine will be set to around 1/4 throttle (1.2 EPR) to provide some balancing between sides.
The engines are tested one at a time as the aircraft's tyres and brakes are not able to hold back the power of both of these Rolls Royce Trent 895-17 engines at once. They produce around 95,000 lbs (43,000kg) of thrust each at full power.
At around the one minute mark you can see the nose wheel tyres bending under stress due to imbalance of power from each engine.
I'm sorry that the sound cuts out but it was too loud for my camera's microphone.
777 200er Power Run
777 200er 80% N2 Power Run , after i found strange residue on engine one and post boroscope full power run was required to satisfy rolls royce concerns , "boy dose it shake around up at power" tryed to capture it best i could and show the jet blast as well
777 TakeOff Roll Eng. Fail Test
This video has two parts. The first part show an animation of what happened when the test pilots simulated an engine failure on the 777 during a takeoff roll. The second part of the film shows a real video of what happened. You can see how the pilots had to apply full right rudder to keep the airplane on the runway. Mr. Santoni explains everything as it happens on the video.
This video was taken at the 2004 Avsim.com Flight Simulator Convention in Denver, CO. The person speaking in the video is Captain Frank Santoni, the chief test pilot for the 777 Program, a position he has held since 1996. He gave a wonderful presentation showing some of the many flight test performed on this amazing airplane. Sorry for the lousy video and sound quality. It was filmed from an old digital camera at the projection screen.
Ground Effect Flight Test On The 777
This video shows how much ground effect affects the 777, and airplane with a very large wing span. It just keep flying down the runway!
This video was taken at the 2004 Avsim.com Flight Simulator Convention in Denver, CO. The person speaking in the video is Captain Frank Santoni, the chief test pilot for the 777 Program, a position he has held since 1996. He gave a wonderful presentation showing some of the many flight test performed on this amazing airplane. Sorry for the lousy video and sound quality. It was filmed from an old digital camera at the projection screen.
