Про движки и их материалы

Nikita, 30.11.2003 15:24:05:

Температура перед турбиной разменивается прежде всего на ресурс.

 

Nikita, 01.12.2003 16:12:52:

У первых серий АЛ-31Ф с которыми как раз и предлагается сравнение, ресурс был более чем скромный. Ситуация пришла в норму только к третьей серии, а это уже 1989 год.

 

Nikita, 01.12.2003 21:45:23:

>Тут есть вопрос: сранивать "напрямую" по годам выпуска, или все же с учетом "степени доработанности".
Конечно напрямую, а иначе в чем смысл-то ???

 

Nikita, 01.12.2003 22:53:30:

Ну можете доведенные только сравнивать. Тогда все еще хуже. -220 придется с АЛ-21Ф "бороться"

 

Конструктор, 01.12.2003 09:18:51:

Ну так "кто-то из ВИАМа" вовсе и не должен понимать "как..реализовали некоторые технологические фишки на новых демонстрационных движках и их компонентах" Это должен делать "кто-то" из ЦИАМа

 

The weak point of the Tomcat was in its engines, which were initially a pair of TF30-P-412 axial flow turbofans, rated at 12,350 lb.s.t. dry and 20,900 lb.s.t with afterburning. This engine was essentially similar to the TF30-P-12 that had been used for the F-111B. With this engine, the F-14A was decidedly underpowered. On several occasions, fan blades broke free from the shaft, damaging the surrounding airframe structure and systems and causing the loss of the aircraft. Very early in the flight test programs there were problems encountered with engine stalls at high angles of attack. These stalls would usually take place when coming either in or out of afterburner or at low power settings when at high angles of attack. These engine problems were exceedingly vexing and resulted in the loss of several aircraft.

Beginning with production block 65, the improved TF30-P-412A engine was fitted. During block 95, which appeared in January of 1977, the P-414 version of the TF30 became available. It incorporated certain modifications intended to prevent turbine blade cracking and to contain any blade failures that did occur. New compressor blades were made from a revised titanium alloy. The engine was provided with steel cases wrapped around the first three fan stages as a containment precaution in the event of blades being thrown by the turbine. This engine was first installed in BuNo 160396 (not the first aircraft in the block 95 batch, as had been originally planned). Existing Tomcats were retrofitted with the P-414, and the last TF30-P-412 powered F-14A was finally phased out of service in the summer of 1979.

The problems with the compressor stalls proved much more difficult to cure, and were not really solved until 1984 when a new and improved variant of the TF30 engine became available. The TF30 turbofan was an extremely fussy engine, and had to be treated with great care by the pilot if compressor stalls were to be avoided. Compressor stalls could occur at any altitude/airspeed combination, but most often they happened at high altitudes and low speeds, when lighting or unlighting the afterburners, or after firing the missiles. Sometimes the engine would immediately recover by itself, but more often than not the stall would "hang", and the engine rpm would begin to decrease and the turbine inlet temperature would start to rise. If not corrected immediately, the aircraft would begin to yaw rapidly back and forth and the aircraft could go into an uncontrollable spin from which the only escape was generally for the crew to eject.

 

Meanwhile, Iran claims that the F-14 accounted for 35 to 45 kills against the Iraqi Air Force for only one shot down. Iran has admitted to up to 12 further losses, but claims they all resulted from engine stall during dogfights rather than enemy fire.

 

Nikita, 02.12.2003 13:42:24:

На F-16 практически точно такой же F100-PW-200 многих проблем Eagle'ов почти не испытывал, за исключением конечно общих крупных косяков типа внезапного разрушения пятого подшипника. А вот F-15 напрягал двигатель совсем не так как предполагалось при проектировании оного.

АЛ-31Ф при Вашем подходе появляется в списке только в 1989 году, однако уже в 1991 его ждет встреча с таким серьезным девайсом как F100-PW-229.

в 1991 придется уже -229 брать, который есть крайне удачный движок почти ничем не "болевший".

 

Nikita, 02.12.2003 14:28:06:

229 это практически новый движок.

 

Valeri_, 02.12.2003 14:59:50:

...всего одну машину (вроде как неправильная предполетная подготовка и обмерзание В/З на взлете) - просто рай .

 

А причем здесь GE ? Болел-то F-14 как раз при P&W'шных TF30

 

The Pratt & Whitney TF30-P-1 turbofan was first flown on an F-111A on July 20, 1965. The first 30 F-111As were equipped with this engine, but they experienced numerous engine compressor stalls, particularly at high speeds and at high angles of attack. These necessitated a change to the 18,500 lb.s.t. TF30-P-3 and to new "Triple Plow I" variable-geometry inlet ducts with larger areas. This engine was later retrofitted in several of the first 30 F-111As. These changes did not entirely cure the stall problems, but the did help somewhat. Many fixes and many years of hard work were necessary before the appropriate air intake geometry was finally found.