F-14 Powerplant

Early in 1984, it was announced that the General Electric F110 powerplant was being procured to power the F-14A(Plus) and F-14D, as well as Air Force F-16 aircraft. The F110-GE-400 gen­erates a maximum of 23,100 pounds-thrust with afterburner as installed in the F-14B and F-14D. The F110 is designed for modular assembly to facilitate maintenance and repair, and numerous borescope ports are positioned along the engine for inspecting critical areas, such as the compressor, combustor and tur­bine assemblies. The core is basically a scaled-down version of the F101 that powers the B-1B coupled with a scaled-up version of the F404 (F/A-18A) fan assembly. In 1987 General Electric was awarded a $235 million four-year contract for 133 engines for the F-14B and F-14D. The contract also contained options for an additional 183 engines.

 The basic F110-GE-400 engine is 181.9 inches long, 46.5 inches in diameter, and weighs 3,830 pounds. When fitted with the hardware unique to the F-14 installation, the engine is 230 inches long and weighs 4,415 pounds. The annular intake incorporates a bullet-shaped spinner and 20 fixed radial vanes with variable trailing flaps. Hot bleed air is used for anti-icing of this area. The original F101 had a two-stage axial fan with a pressure ratio of 2.3:1 and a mass airflow of approxi­mately 250 pounds per second. In the F110, a three-stage fan using titanium blades with a pressure ratio of 3:1 was added, enabling a mass airflow of 270 pounds per second. Variable inlet guide vanes are located forward of the fan. The bypass ratio of the engine is 0.87:1.

The first three stages of the axial-flow com­pressor are made from titanium, the remaining six from heat-resistant 8286 steel. The annular combustion chamber is short and designed for smokeless operation. It is machined from Hastelloy-X with 20 dual-cone fuel injectors and swirl-cup vaporizers. Hot gases pass to a single-stage high pressure turbine with con- vective and film-cooled blades and vanes manufactured from Rene 125. Turbine inlet temperature is approximately 2,500°F. From the high pressure turbine the gases pass to an uncooled two-stage low pressure turbine, and then to the afterburner.

 The most significant difference between the TF30 and the F110 is the size of the engine. The TF30 is 52 inches longer from front face to nozzle outlet than the F110. If the front face of the F110 were to be mated with the existing inlet, the exhaust nozzle would be wrongly positioned, while if the nozzle were positioned correctly, a new and complex inlet would need to be designed. Both conditions would proba­bly upset the aircraft’s center of gravity. To solve the problem, General Electric and Grumman devised a way to stretch’ the engine. This was done by adding a 50 inch parallel-sided section between the engine core and afterburner sections. This effectively moved the engine face forward 39 inches and the nozzle aft 11 inches. Minor changes to the F110 engine mounting points were also required, since the TF30’s forward mounting point was 30 inches from the front face, and the F110’s is only 10 inches back, and slightly higher on the engine.

Installation of the F110 required a minimum of structural changes to the airframe, none of which involved primary structure. The nacelle deck frames and inboard side beam stiffeners required slight rework, while gaps between the new afterburner nozzle and the aft fuselage sponson and centerbody need filled by aero­dynamic covers. The existing inlet and ducting can handle the airflow to the engine, changes being restricted to altering the ramp schedul­ing. A new air turbine starter with increased horsepower for starting the FIIOs is installed. In addition, new generators and constant speed drives are used in the F110 powered F-14S. The hydraulic pump and the motive flow pump will be the same units used on the F-14A with modifications to the splines required to meet the F110 interface.

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