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Mensaje: <blockquote data-quote="SuperEtendard" data-source="post: 1039717" data-attributes="member: 128">Yo los datos que tengo son un tanto antiguos, pero quizás ayude:In the case of the IAF we can draw on figures for annual flying hours from the CAG reports between 1992 and 1998, and the 1998 Report of the Kalam Committee on Air Safety to arrive at a clear picture of IAF attrition over the period 1991/92-1996/97. The figures for 1997/98 amd 1998/99 are based on the Minister of Defence's written replies to Parliment in August 1999. Annual Flying hours: IAF Year Flying Hours 1991/92 256,200 1992/93 238,362 1993/94 238,362 1994/95 252,822 1995/96 268,385 1996/97 275,505 1997/98 306,190 Total Flying Hours 1991/92-1997/98: 1,836,875 The IAF's fleet breakdown (fighters vs. others) is approximately 60:40. However, we know that 50% of the IAF flying hours in 1997/98, or 153,000 hours, were contributed by fighters. Based on this, it is not unreasonable to assume that 50% of the hours, or 90,708 hours, during the first 7 months of 1998 would have been put in by fighters. This means that the fighters logged up about 243,708 flying hours during this 19 month period. Over this period the IAF lost 3 fighters in 1997 (2 MiG-21, 1 MiG-27) and 8 fighters (6 MiG-21, 1 MiG-23, 1 MiG-29) during the first seven months of 1998. This means that the loss rate for Indian fighters was 0.45 per 10,000 hours. Fuente: <a href="http://www.bharat-rakshak.com/MONITOR/ISSUE2-4/rupak.html">http://www.bharat-rakshak.com/MONITOR/ISSUE2-4/rupak.htm</a>Y esto con respecto al MIG-21:Very many of the MiG 21s lost were in these three regimes of flight. Even in civil airliners most accidents occur during these three phases but: 1) The alpha sensitivity of the MiG21 ,because of the low aspect ratio of 2.2, requires much more precision than the same maneuver when executed in an aircraft with a aspect ratio of 5.6 as in a basic trainer. 2) The continual, if inevitable, weight increase in the MiG 21 meant that the approach speed in the later marks had to be made at a higher and higher speed. This reduced the amount of surplus power available to accelerate away from a "coffin corner "situation". In India the hot weather meant the engine was producing about 12%less thrust and the wing was producing about 12% less lift to begin with. 3) In case of an emergency, to gain height, the pilot in a Hunter or a Kiran would open up the throttle and pull back the stick- things which are instinctive even in a rookie pilot. Ina MiG the pilot has to push the stick forward, build up his energy and then after a delay of several seconds, pull back the stick to climb away. He may simply not have the time when flying close to the ground. 4) The CK ejection seat, one of the best for high speed high altitude ejection simply was not good enough for low level by modern standards. One of the clever features of the CK seat was that as the seat left the cockpit the canopy- which was hinged to the front of the windshield in the FL - attached itself to the top of the ejection seat and rotated itself until it covered the entire front of the ejection seat- thus giving unparalled blast protection when ejecting at supersonic speed. I remember a Martin Baker engineer getting very interested in how the thing worked. I had seen the seat but he had not! Unfortunately I was not able to help him. The semi -encapsulation feature delayed ejection in that it took too long to get rid of the canopy after clearing the aircraft and this delayed clear release and deployment of the Parachute. The 300 kmph, 100 meters minimum parameters meant that many low level ejections were unsuccessful. Is the general accident level too high? According to the MOD the IAF lost a total of 315 MiG 21 were lost from all causes in 40 years. Taking out the combat losses this is less than 30% of the MiG fleet in 40 years. Compared to the Canadian losses of 50% and the German Losses of 292 out of 915 F104s in a much shorter period of operation and the fact the percentage of Lightning losses for the RAF were just as high would indicate that losses were not unusual. 2) The loss rate of the MiG 21 is in no way worse than any similar fighter of its genre and better than most. Applying western accident rates is also somewhat unrealistic because of significant decay in thrust and lift due to high air temperatures. A 12% decrease in lift or thrust can lead to a 100% difference between crashing or getting back safe. There being no easy mathematical co-relation. Fuente:<a href="http://www.bharat-rakshak.com/IAF/Info/Aircraft/MiG-Prodyut.html"> http://www.bharat-rakshak.com/IAF/Info/Aircraft/MiG-Prodyut.html</a>Saludos</blockquote>

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