- Materials & Industrial Technology
The F-14 Tomcat: Air force Technology
Aircraft engineers involved in the evaluation of aircraft kinetics and the development of flight control systems can source their ideas from existing aircraft designs that have been relatively successful. This can be a very indispensable way of understanding aircraft dynamics. This complete work seeks to discuss the aerodynamic characteristics of Grumman’s F-14 Tomcat. Lateral dynamics and feedback controls are extensively discussed. This paper ends with a discussion of the system design process and assessment, including the flight control systems.
The F-14 Tomcat: Air force Technology
The F-14 Tomcat is a variable sweep wing, twin-engine, two-seat supersonic, two-seat fighter jet designed and manufactured by the Grumman Aircraft Corporation. The aircraft was developed during the United States Navy’s Naval Fighter Experimental program. It was developed due to the observation of the performance combat aircraft against MiG fighter jets during the Vietnam War. It was first flown in December 1970 and was subsequently deployed in 1974 (Isham, 2010).
It served as the United States Navy’s chief air superiority fighter and received a Low Altitude Navigation pod for Night time targeting in the 90s; this enabled it to perform precise ground attack missions. It was retired from an active role by the Navy in September 2006 (Isham, 2010).
According to Isham (2010), the F-14 Tomcat has undertaken multiple types of sorties, including; accurate ground mission strikes, fleet air defense and air superiority.
The F-14 can deploy a variety of air to ground weapons in several configurations. It also has a targeting system that enables it to precisely deliver laser guided bombs during air to ground sorties. It has a Fast Tactical Imagery system which enables it to receive and transmit reconnaissance imagery during missions to enable it to provide real time strike capability (Donald, 2004).
The F-14’s original design was as a long range interceptor and as an air superiority fighter jet. It features a two-seat cockpit, surrounded by a bubble canopy which facilitates a 360 degrees view during flight. Aerodynamically, the F-14 is an advanced aircraft. It is more maneuverable, faster, possesses a greater acceleration and has a longer range. These features were achieved through; the extensive use of titanium to provide enhanced structural to strength ratios, advanced gas turbine turbofan engines to improve strength to weight ratios for higher thrust with low fuel consumption and a variable geometry wing with automatic sweep capabilities, flaps, and slats for maneuvering and glove vanes.
The aircraft features wings that sweep back for high-speed intercept flight and sweep forward for flights requiring lower speeds. The orientation of its fuselage together with its wings outline allows it to gain altitude faster during takeoff. It has twin engines, housed in nacelles which are three feet apart. The flat space between the nacelles is meant to carry the aircraft’s fuel, as well as housing avionic mechanisms like the wing sweep mechanism and various flight controls. The underside is used to carry aircraft’s assorted bombs and its Sparrow or Phoenix missiles. The fuselage itself provides the aircraft with approximately 40 to 60 percent of its aerodynamic lift, depending on the position of the wing sweep.
Donald (2004) asserts that the most notable aerodynamic feature of the F-14 Tomcat is the incorporation of the element titanium in its airframe to replace aluminum. The net effect of this is a reduced structural weight and high maneuverability. This improves all the aircraft’s features including; range, acceleration, climb characteristics and payload.
Significant aerodynamic characteristics
Variable wing geometry
The aircraft’s wing sweep can be shifted approximately 20 to 68 degrees during flight; this can be automatically managed by the Central Air Data Computer. The computer seeks to keep the wing sweep at an optimal lift to drag ratio; this happens as the Mach number changes (Friedman, 2006). Whenever desired, pilots can manually override the system. During storage, the aircraft’s wings can be swept to 75 percent to overlay the horizontal stabilizers. This helps in saving storage space aboard aircraft carriers.
During emergencies, the F-14 Tomcat can land with its wings fully swept at 68 degrees. However, this is significantly hazardous as a result of the great air speeds involved. The F-14’s wing characteristics are what made it an excellent air superiority fighter in its time. The special features of the F-14 made it the best fighter of its time (Isham, 2010).
At low speeds, the F-14’s slats give it a considerable improvement in lift. This is achieved through reducing the effective wing loading to fifty PSF (pounds per square foot), from 85 PSF. This increase in lift is optimal with the wings swept at 22 degrees in the full forward formation.
Automatic wing sweep programming is novel and dramatic advantage that has never been witnessed before in any other known fighter jet. It takes the wings from the maximum sixty-eight degrees sweep to the full forward twenty-two degrees forward swept position. This automatic sweep programming enables the aircraft’s wings to capitalize fully on the characteristic span loading payoff of variable sweep in a phenomenon known as ‘riding the envelope.’ It is this feature that gives the fighter an advantage during dog fights since it materially enhances the jet’s superiority in a dog fight.
The F-14 has glove vanes which can both be manually and automatically controlled. Their full application is at supersonic speeds. Their main advantage is that they lower the drag (tail load), thus increasing the thrust (power) available (Friedman, 2006). Several types of aircraft use canards to fill in the same role as glove vanes. However, they are not as effective in enabling the fighter to accomplish the highest lift over drag during high altitude flights. This unique advantage confers the F-14 significant abilities, including the ability to execute tight turns during high altitude flights where supersonic speeds are also needed. The passive control of wing sweep and the extra feature of glove vane is a very important feature. The glove vanes produce additional lift before the F-14’s center of gravity; this helps in compensating for nose down pitching which occurs at supersonic speeds. In any modern aircraft such as the F-14, there are numerous advantages which combine the creativity and design ingenuity of its builders, designers, operators, and pilots.
The wings feature a two spar design with integrated fuel tanks; much of it is made from titanium. The aircraft lacks ailerons; roll control is obtained from spoilers mounted on the wings. The slats and flaps span the entire wing; this enhances lift for both landing and combat sorties. The twin tail design aids in maneuvering the fighter at high angles of attack.
In summary, the F-14 is an advanced air superiority fighter originally intended for fleet air defense (Gardner, 2003). It offers improved performance over other fighters in its class. It possesses an aerodynamic advantage which guarantees it an advantage in general combat.