Cerco disperatamente il video del primissimo volo dell' f16-y il dimostratore!
In decollo aveva mostrato grande instabilità e il pilota abilissimo era riuscito a ricondurlo sulla pista
Rigrazio chiunque per la preziosa segnalazione!!!!!
VIDEO F-16 Y chi lo ha?
YF-16 primo volo non ufficiale video (praticamente è decollato x errore - richiede real player)
The YF-16 was the first of two prototypes to make it into the air. In January 1974, a General Dynamics test pilot named Philip Oestricher wasperforming a high-speed taxi test. During the test, he discovered a problem with the horizontal stabilizer, which caused the aircraft to inadvertently lift off the ground. Instead of risking a high-speed abort, Oestricher allowed the aircraft to fly and was airborne for approximately six minutes before safely landing.
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Saab JAS39 Gripen video
1. The prototype of the Gripen wasn't so successful: it crashed on his sixth flight, on February 2, 1989 at Linkà¶ping. The pilot flew for the first time with the Gripen, he had some problems with the stability (fly-by-wire) of the fighter. During the landing he hit with his left-wing the runway and crashed. The pilot had only a broken elbow.
2. Gripen crash caused by flight control software.
On Feb 2 the 1st prototype (of 5) of Sweden's Saab JAS39 Gripen fighter crashed on landing after its 6th test flight. It impacted, broke left main gear, bounced, skidded and flipped.
``Gripen is naturally unstable and has a triplex digital fly-by-wire system with a triplex analogue backup.''
Initial flight was ``some 18 months behind schedule'' and this was ``attributed to difficulties in proving the software for the flight control system.''
After the 1st flight, test pilot ``remarked that the control system seemed too sensitive and that the control laws would probably need to be changed.''
On all flights ``the aircraft experienced problems with lateral oscillations.'' [On the] ``last flight oscillation in pitch was also apparent.''
The accident investigation committee chairman ``confirms earlier assumptions that the flight control system was at fault.''
Chairman: ``The accident was caused by the aircraft experiencing increasing pitch oscillations (divergent dynamic instability) in the final stage of landing, the oscillations becoming uncontrollable. This was because movement of the stick in the pitch axis exceeded the values predicted when designing the flight control system, whereby the stability margins were exceeded at the critical frequency.''
Separate investigation by the JAS Industry Group: ``The control laws implemented in the flight-control system's computer had deficiencies with respect to controlling the pitch axis at low speed. In this case, the pilot's control commands were subjected to such a delay that he was out of phase with the aircraft's motion.'' ``the company hopes to fly JAS39-2 before the end of the year.'' ``Delivery of the first production aircraft [...] is now expected in [1993, although typo said `1933'], instead of 1992.''
3. Swedish Gripen Fighter Crash. Swedish wind cuts fly-by-wires.
Flight-control software has been blamed for the crash of the prototype Swedish Gripen fighter last February. The preliminary report from the Swedish government's crash-investigation commission indifified the software's inability to cope with gusting winds and the oversensitivity of the control system as the prime reasons for the accident. According to a spokesman for the commission, problems with the \pound 3.2 billion project first arose in an earlier flight test. "The preceeding test flight had shown up problems, but it's not a problem with the aircraft or with the flight control systems. It's a software problem.
"The whole of the control system was too sensitive for the pilot; it operated too fast. It was too easy for the pilot to go outside the flight-control envelope into unstable flight." In common with many fighters currently being developed, the JAS39 Gripen is designed to be inherently unstable to increase its manoeuverability. It relies on the software to keep it under control. "There were limitations on the flight control systems, but during the landing phase the wind was stronger than allowed for by these limitations. The pilot had to try to overcome them."
A final report into the crash is due in May, but work has already started on the second prototype aircraft, including a modified version of the flight-control software.
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F-22 Raptor video
1. On April 25th 1992, this F-22 prototype crashes on the runway at the Edwards Air Force Base. The plane pitches forward and back 40 feet (12 m) above the runway, lands hardly without gear down, slides 8000 feet (2400 m), and partially burns. The pilot was not seriously hurt.
Investigations showed that the accident was caused by Pilot Induced Oscillations (PIO happens when the flight controls reacts too slowly in regards to the pilot orders).
2. Unfortunately, N22YX was involved in a major accident on May 25, 1992 when it belly-flopped onto the runway after 8 seconds of violent pilot-induced oscillations. It slid several thousand feet down the runway and caught fire, destroying some 25 percent of the airframe. Pilot Tom Morgenfeld was uninjured, but the aircraft was deemed too badly damaged for economical repair.
At the time of the crash, Morgenfeld had been carrying out a planned go-around, and he had just switched on his afterburners and had retracted his undercarriage at less than 50 feet off the runway with thrust vectoring active. At a speed of 175 knots, the aircraft began an uncommanded pitchup followed by a severe stick-forward command from the pilot. The aircraft then entered a series of pitch oscillations, with rapid tail and thrust nozzle fluctuations, exacerbated by control surface actuators hitting rate limiters causing commands to get out of synchronization with their execution.
An investigation later showed that Morgenfeld had ignored a test-card that required that the vectoring nozzles to be locked into position in just such a configuration that he had found himself at the time of the crash. However, most engineers had also ignored this instruction since they thought it to be unnecessary. At the time of the accident, the aircraft had made some 760 flights and had logged 100.4 hours in the air.
After this accident, no further flight testing of the prototypes was carried out, and the program moved into the EMD phase. The other YF-22 (N22YF) was later stripped of its engines and was used for ground testing. N22YF is now on display at the USAF Museum in Dayton, Ohio.
Ciao.
The YF-16 was the first of two prototypes to make it into the air. In January 1974, a General Dynamics test pilot named Philip Oestricher wasperforming a high-speed taxi test. During the test, he discovered a problem with the horizontal stabilizer, which caused the aircraft to inadvertently lift off the ground. Instead of risking a high-speed abort, Oestricher allowed the aircraft to fly and was airborne for approximately six minutes before safely landing.
----------------------------------------------------------------------------------------
Saab JAS39 Gripen video
1. The prototype of the Gripen wasn't so successful: it crashed on his sixth flight, on February 2, 1989 at Linkà¶ping. The pilot flew for the first time with the Gripen, he had some problems with the stability (fly-by-wire) of the fighter. During the landing he hit with his left-wing the runway and crashed. The pilot had only a broken elbow.
2. Gripen crash caused by flight control software.
On Feb 2 the 1st prototype (of 5) of Sweden's Saab JAS39 Gripen fighter crashed on landing after its 6th test flight. It impacted, broke left main gear, bounced, skidded and flipped.
``Gripen is naturally unstable and has a triplex digital fly-by-wire system with a triplex analogue backup.''
Initial flight was ``some 18 months behind schedule'' and this was ``attributed to difficulties in proving the software for the flight control system.''
After the 1st flight, test pilot ``remarked that the control system seemed too sensitive and that the control laws would probably need to be changed.''
On all flights ``the aircraft experienced problems with lateral oscillations.'' [On the] ``last flight oscillation in pitch was also apparent.''
The accident investigation committee chairman ``confirms earlier assumptions that the flight control system was at fault.''
Chairman: ``The accident was caused by the aircraft experiencing increasing pitch oscillations (divergent dynamic instability) in the final stage of landing, the oscillations becoming uncontrollable. This was because movement of the stick in the pitch axis exceeded the values predicted when designing the flight control system, whereby the stability margins were exceeded at the critical frequency.''
Separate investigation by the JAS Industry Group: ``The control laws implemented in the flight-control system's computer had deficiencies with respect to controlling the pitch axis at low speed. In this case, the pilot's control commands were subjected to such a delay that he was out of phase with the aircraft's motion.'' ``the company hopes to fly JAS39-2 before the end of the year.'' ``Delivery of the first production aircraft [...] is now expected in [1993, although typo said `1933'], instead of 1992.''
3. Swedish Gripen Fighter Crash. Swedish wind cuts fly-by-wires.
Flight-control software has been blamed for the crash of the prototype Swedish Gripen fighter last February. The preliminary report from the Swedish government's crash-investigation commission indifified the software's inability to cope with gusting winds and the oversensitivity of the control system as the prime reasons for the accident. According to a spokesman for the commission, problems with the \pound 3.2 billion project first arose in an earlier flight test. "The preceeding test flight had shown up problems, but it's not a problem with the aircraft or with the flight control systems. It's a software problem.
"The whole of the control system was too sensitive for the pilot; it operated too fast. It was too easy for the pilot to go outside the flight-control envelope into unstable flight." In common with many fighters currently being developed, the JAS39 Gripen is designed to be inherently unstable to increase its manoeuverability. It relies on the software to keep it under control. "There were limitations on the flight control systems, but during the landing phase the wind was stronger than allowed for by these limitations. The pilot had to try to overcome them."
A final report into the crash is due in May, but work has already started on the second prototype aircraft, including a modified version of the flight-control software.
-------------------------------------------------------------------------------------
F-22 Raptor video
1. On April 25th 1992, this F-22 prototype crashes on the runway at the Edwards Air Force Base. The plane pitches forward and back 40 feet (12 m) above the runway, lands hardly without gear down, slides 8000 feet (2400 m), and partially burns. The pilot was not seriously hurt.
Investigations showed that the accident was caused by Pilot Induced Oscillations (PIO happens when the flight controls reacts too slowly in regards to the pilot orders).
2. Unfortunately, N22YX was involved in a major accident on May 25, 1992 when it belly-flopped onto the runway after 8 seconds of violent pilot-induced oscillations. It slid several thousand feet down the runway and caught fire, destroying some 25 percent of the airframe. Pilot Tom Morgenfeld was uninjured, but the aircraft was deemed too badly damaged for economical repair.
At the time of the crash, Morgenfeld had been carrying out a planned go-around, and he had just switched on his afterburners and had retracted his undercarriage at less than 50 feet off the runway with thrust vectoring active. At a speed of 175 knots, the aircraft began an uncommanded pitchup followed by a severe stick-forward command from the pilot. The aircraft then entered a series of pitch oscillations, with rapid tail and thrust nozzle fluctuations, exacerbated by control surface actuators hitting rate limiters causing commands to get out of synchronization with their execution.
An investigation later showed that Morgenfeld had ignored a test-card that required that the vectoring nozzles to be locked into position in just such a configuration that he had found himself at the time of the crash. However, most engineers had also ignored this instruction since they thought it to be unnecessary. At the time of the accident, the aircraft had made some 760 flights and had logged 100.4 hours in the air.
After this accident, no further flight testing of the prototypes was carried out, and the program moved into the EMD phase. The other YF-22 (N22YF) was later stripped of its engines and was used for ground testing. N22YF is now on display at the USAF Museum in Dayton, Ohio.
Ciao.