A) The Control Surfaces of the F-117 B) Armament C) The Cockpit D) Flight Control System E) Weapon Bays The F-117 was developed to counter the 1970 Russian deployment of new radar networks and improved radar guided SAMs (Surface-to-Air Missiles) and new interceptors with improved radar systems that threatened any bombers trying to strike their target.
The F-117 achieves its low RCS (Radar Cross Section) mainly by its design which reduces its radar signature over 85 percent. All previous military aircraft have had curved shapes with little to no flat faces. The problem with the curved design is that figuring how every single radar wave is going to reflect from the curved surfaces of the airplane becomes extremely difficult. It is important to know how the radar waves are going to bounce off a stealthy plane because if in order for the enemy radar to pick up the plane some radar waves being emitted have to bounce off the plane and return back. The "faceted" design of the F-117 reflects the radar waves sent at it away from the place that sent them so that even if the waves are hitting the plane none return to alert the enemy radar to the F-117's presence.
This design greatly reduces its RCS but also caused some large problems. The main problem with the airframe design is that it causes major instability in the plane. Some previous military airplanes are unstable to a certain degree. In fact many fighters and bombers were designed to be unstable so they would be more maneuverable like the General Dynamix F-16 Fighting Falcon that is unstable on only one of its three axis. It is only unstable on the pitch axis (nose moving up or down). Compensating for just one axis took some work and a fairly complex computer. The computer inside the F-16 keeps it stable for the pilot. The F-117 on the other hand is highly unstable on all three axis: pitch, roll (wing movement up and down), yaw (nose movement from side to side). This design would not have been used 20 years ago because the computers then were to big or slow to keep the airplane stable. Stability is especially important for the F-117 because its a bomber and trying to drop bombs from a unstable object with any precision is very difficult.
The development of the F-117 was made possible by several recent technological developments which included an improved method for testing the radar cross section and Infrared or heat signature of an object, the development of a fly-by-wire flight control system, the development of advanced composite or radar absorbing materials, also the development of new designing tools like computer aided design (CAD) and computer aided manufacturing (CAM) that reduced the cost and development time.
After the designs were completed the United States Air Force and Defense Advanced Research Projects Agency gave Lockheed approval to build two experimental survivable testbed (XST) air vehicles using as many off the shelf components as possible to reduce the development costs. This project was code named Haven Blue. The first XST would be used to test the flying characteristics of the F-117 while the second would test the airplanes radar signature. To further reduce development costs the two experimental aircraft were built without a weapons bay or the ability for inflight refueling also small engines were used.
The two experimental survivable testbeds were constructed at Lockheed plant 10 Palmdale, California.
When the two test aircraft were completed they where only 7.5 feet and only 12,000 pounds making them some of the lightest airplanes ever flown. The two XST were not very fast. In fact they could only go Mach 0.8 for 1 hour.
The first experimental F-117 was completed in November 1977 and then delivered to a testing area in the Nellis test range complex.
Both Have Blue aircraft were lost during testing. The first one was lost during a landing when the force of the landing caused one wheel of the landing gear to raise. Because landing was now impossible the pilot ejected. During the ejection the pilot (Bill Park) hit his head and therefor sustained serious back injuries when he landed.
The other XST was lost on its 52 flight when one of the engines caught fire and the pilot (Lt. Col. Dayson) was forced to eject. Before it crashed however it proved that a "faceted" airplane could fly and also not be detected by radar.
After the Have Blue project was completed Lockheed was given permission to build 5 full scale development planes for further testing. These five planes were larger and heavier than the Have Blue aircraft. They also had more equipment like a parachute breaking system and the addition of weapon bays. Also many of the F-117's systems were redesigned.
The first full scale development aircraft crashed when it was delivered on April 20, 1982. The controls had been assembled incorrectly so that what should have controlled the pitch of the plane now controlled yaw and vice versa. The pilot (Robert L. Riedenauer) did not have a chance to eject before the aircraft last control and crashed. He was not killed by the crash but severely injured and forced to retire from flying.
The aircraft were further tested but only at night for security reason. During the testing to other crashes occurred killing the pilots. The existence of the F-117 was declassified on November 10, 1988 at the Pentagon.
Before this time there were rumors about the stealth fighter but the rumors described a plane completely different then the actual F-117. The rumors said that the aircraft achieved its low radar signature by making the airframe very curved while the real F-117 was very angular. Also the designation of the aircraft was a surprise because the F-117 was thought to be named the F-19 to fit the gap between the McDonnell Douglas F-18 and the Northrop F-20. Instead the F-117's designation was a Century-series designation that was thought to have ended years ago.
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The F-117 has a very high landing speed because of its design and its lack of flaps. Flaps are areas of the wing that can extend from the wings. The flaps are usually only used on landings because the flaps create more lift allowing the aircraft to go slower without stalling which lets the plane have a low landing speed. Because the F-117 has no flaps its landing speed is about 160 knots or 240 miles per hour. After the F-117 lands on the runway it has to slow down quickly before it runs out of runway. The F-117 uses conventional wheel breaks as well as a parachute breaking system that extends from the rear. The parachute can also be used to recover from a spin.
The F-117 has four elevons that move up and down about 60 degrees. These elevons are used to dip or raise a wing or to raise or lower the entire plane. The F-117 also has two rudders that move left and right about 30 degrees. These rudders move the entire plane from side to side.
The F-117 has no defensive weapons like air to air missiles or internal cannon to protect itself. Instead it relies on its ability to move around undetected.
The cockpit of the F-117 provides good side to side visibility for about 90 degrees on either side. The cockpit also has some blind spots. The pilot has several blindspots. The biggest is above the pilot because the top panel of the F-117's cockpit is nontransparant. To further reduce the F-117's radar signature the five panels that make up the cockpit are specially treated to better reflect radar waves. The pilot uses a ACES II ejection system to eject from the plane. The same system is being used in the F-18 C and D.
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The F-117 uses a all-digital fly by wire flight control systems. This system is what keeps the F-117 stable. The system itself is quadruple redundant and very similar to the flight control system used in the General Dynamix F-16 C and D. The only major difference is the computer software used in the F-117.
There are two weapon bays that have enough space to hold 2,500 pounds of ordinance each for a total of 5,000 pounds. The F-117 cannot carry any external weapons because it would make the F-117 radar detectable.
| Primary Function: | Destroy enemy ground targets |
|---|---|
| Manufacturer: | Lockheed Skunk Works |
| Crew: | One |
| Engines: | Two General Electric F404-GE-F1D2 non afterburning engines. |
| Thrust: | 10,000 pounds of static thrust each |
| Length: | 65.9 feet |
| Height: | 12.5 feet |
| Wingspan: | 43.3 feet |
| Weights: Gross weight: Fuel weight | 28,5000 pounds 52,500 pounds 19,000 |
| Combat radius: | 900 miles |
| Max speed: | Mach 0.8 |
Choose a different fighter.