Military

J85

The General Electric J85 turbine jet engine is used on the F-5 military fighter jet and the T-38 military trainer aircraft. The F-5 is a low-wing monoplane equipped with an all-moving horizontal tall mounted in the low position; the fuselage is carefully contoured in accordance with the transonic area rule. Small side-mounted inlets supply air for the two General Electric J85 afterburning turbojet engines.

The Northrop T-38 is a small low-wing two-seat trainer airplane, with a maximum weight of 12,000 lb. It is powered by two General Electric J85 afterburning turbojet engines located close together in the aft fuselage, each with 3850 lb of thrust. The first T-38 built flew in 1959. More than 1,100 were delivered to the Air Force between 1961 and 1972 when production ended. Approximately 562 remain in service throughout the Air Force and other facilities. The T-38 needs as little as 2,300 feet of runway to take off and can climb from sea level to nearly 30,000 feet in one minute. The engine problems in the T-38 aircraft were being addressed with almost $289M in the FY2001-05 FYDP for J85 engine modernization and other propulsion upgrades. The T-38 Propulsion Modernization Program (PMP) is comprised of four contractual efforts: a J85-5 engine modification and ejector nozzle will be sole source additions to a current contract with General Electric, b) the inlet/former/bulkhead kits will be a competitive award; c) a task order will be established on the existing Contractor Field Team (CFT) contract for kit installation; and d) the T-38 software changes required by the PMP will be added to the existing Boeing contract for the AUP.

General Electric J85 turbojets engines were used in the prototype for the F-117 Stealth fighter.

The X-14 accomplished its first flight on 19 February 1957 as a vertical takeoff, hover, and vertical landing. The first successful transition from hover to forward flight on occurred on 24 May 1958. In 1959, the Viper engines were replaced by General Electric J85 engines and the aircraft was delivered to the NASA Ames Research Center as the X-14A where it was used as a test aircraft until early 1963.

The C-123 featured high-mounted wings and tail surfaces on a pod-type fuselage which made for easy rear end, unobstructed on and off loading. Because of its powerful engines, it showed superior ability to operate in short field landings and take offs. It could carry 61 fully equipped troops for assault or evacuate 50 patients on litters plus six attendants. In 1966, some models were fitted with auxiliary powerplants in a pylon-mounted 2,850 lbs. thrust GE J-85 turbojet outboard of each engine. These were for emergency use.

Vietnam era gunships included the Spectre (AC-130), Shadow (AC-119G) and Stinger (AC-119K) with increases in airspeed, armor, altitudes, and computer aided guns. The AC-119G was a gunship conversion of the C-119G with four 7.62mm miniguns installed. The AC-119K's were modified "Shadow" gunships with two J85 auxiliary jet engines installed and two 20mm cannons.

Using a combination of radar reflectors, chaff, electronic repeaters, and infrared simulators to mimic the large B-52 bomber, the diminutive ADM-20 Quail decoy could be programmed to execute at least one change in cruising speed and two turns after being released from its B-52 carrier. Powered by a single General Electric J85-GE-7 turbojet engine, the Quail could achieve a maximum speed of Mach 0.85 at 50,000 feet.

The BQM-34S Aerial Target is a recoverable, remote-controlled subsonic target capable of speeds up to 0.9 MACH and altitudes from 10-50,000 feet. It is propelled during flight by a single J69-T41 or J85-GE-100 turbojet engine which produces 1,920 or 2,800 pounds static thrust (respectively) at sea level.

In all, Bell Aerosystems, Buffalo, NY built five LM trainers of this type for NASA. Two were an early version called the Lunar Landing Research Vehicle ( LLRV ). Neil Armstrong was flying LLRV-1 on May 6, 1968 when it went out of control. He ejected safely and the vehicle crashed. A later version was called the Lunar Landing Training Vehicle or LLTV and three were built. Two of these were lost in crashes on December 8, 1968 (LLTV-1 piloted by Algranti) and January 29, 1971 (piloted by Stuart M. Present). Both pilots ejected safely. The LLTV was a more accurate LM simulator. The LLTV was for training in the critical final phases of the descent, from 500 to 700 feet on down. It had a J85 jet engine which, basically, maintained a constant thrust - based upon the weight of the vehicle - and took away 5/6th of the weight. That put you in a simulated lunar one-sixth gravity environment. There were sets of RCS thrusters, just like the lunar module, to control attitude. In addition, there were two other, vertically-mounted, hydrogen-peroxide-fueled 'lift' rockets that were capable of handling the extra one-sixth of the weight above the five-sixth that the J85 removed.

Given the cost of experimental flight aircraft and the evolution of increasingly sophisticated electronic and simulator systems, it was perhaps inevitable that NASA eventually turned to smaller, pilotless radio-controlled aircraft. In the 1980s, this idea was embodied in the HiMAT, a contraction of Highly Maneuverable Aircraft Technology. The HiMAT, powered by a General Electric J85 turbojet engine, had a length of 23 feet and a wing span of 16 feet.

The J85 engine was originally designed for a maximum flight speed of Mach 2. Engine performance drops off past Mach 2, and increased compressor temperatures approach material limits. In early 1998 NASA Lewis researchers completed a series of tests inside the Center's Propulsion Systems Laboratory to evaluate the operability of a General Electric J85-21 turbojet engine that they retrofitted to run at Mach 3, 1-1/2 times faster than its maximum flight speed of Mach 2. The tests were part of an overall program, supported by NASA's Hypersonics Office, to develop a turbine-based combined-cycle propulsion concept that may one day propel aircraft and spacecraft from take-off to hypersonic speeds of more than 5 times the speed of sound. The NASA Lewis concept could revolutionize high-performance aircraft and ultimately make space exploration more affordable by using air-breathing propulsion.

J85-5

Manufacturer:
General Electric
 

Specs:

Military Thrust 2680 lbs
Weight -
600 lbs
Compressor -
8 Stage Axial
Turbine -
2 Stage Axial
Application -
T-38 Jet Trainer, F-5 Tiger II
A-37 (non-afterburning)

Max RPM
16,550




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