F-5 Aerial Refueling Modification Kit

developed independently of northrop by tca

In response to the requirement to add aerial refueling capability to F-5 aircraft that did not receive structural provisions during manufacture, TCA has developed a proprietary structural and systems modification kit to allow these aircraft to be capable of day or night refueling of all internal fuel cells and selected external fuel tanks using the “probe-and-drogue” system. The TCA Aerial Refueling (AR) System consists of permanently installed components and structural reinforcements along with an external, detachable AR probe assembly. The TCA AR System is applicable to all F-5s including the F-5A/B/E/F.

The TCA AR modification kit is the only one that has been developed for the dual-seat F-5F. Importantly, TCA’s AR modification kit has been certified by the USAF. The first customer for the TCA AR System was the Fuerza Aérea de Chile (FACh) for 13 F-5E and 3 F-5F AR Systems. The TCA F-5 AR System is in daily operational service. It incorporates many proprietary design features and has been approved for refueling with KC-135, KC-10, KC-130 and S-3A tankers.

F-5 AIM-9M Carriage Kits

replaces unsupported AIM-9J/P

Working in cooperation with the USAF Tactical Missile Technical Coordinating Group (TMTCG) at Warner Robins AFB, TCA has developed a modification kit that will allow the F-5 aircraft to carry the latest AIM-9M versions of the Sidewinder that are actively supported by the USAF/USN.

When the F-5 was originally developed, it was designed to be capable of carrying 2 AIM-9 Sidewinder air-to-air missiles on wing-tip mounted launcher rails. The Sidewinder missiles that were in service during this time period were the AIM-9B/E/J/P. In order to shoot down an aircraft with these versions of the Sidewinder, the missile seeker needed to be positioned so that it received the highest possible heat signature from the target. This meant that the launching aircraft needed to be maneuvered to the rear aspect of the target in order for the seeker to lock onto the hot engines exhaust of the target aircraft. In the years following the development of the F-5, the Sidewinder missile has gone through several design improvements that have dramatically increased its lethality. Most notably, the current versions of the Sidewinder have seekers that are so sensitive that they can detect and tract an aircraft’s heat signature even when looking at the target from the frontal aspect (i.e. head-on). The current in-service versions of the Sidewinder are the AIM-9L/M.

Logistics support for the older B/E/J/P versions of the Sidewinder missiles is becoming difficult since they are no longer in the US inventory. Furthermore, many F-5 operators now also have either the F-16 or the F/A-18 in their inventory. Both of these aircraft carry the latest AIM-9M versions of the Sidewinder. Due to the lack of reliable logistics support for the older missiles and due to the improved combat effectiveness of the later missiles, many F-5 operators have requested USAF support to modify their F-5 aircraft to be capable of carrying the same versions of the Sidewinder that are carried on their F-16 or F/A-18 aircraft.

The key components of the Tiger Century AIM-9L/M modification kit for the F-5 are the new launcher rails. New wingtip launcher rails (based on the original LAU-100/101) have been designed by TCA that incorporate all design changes required for full AIM-9L/M compatibility. These new launcher rails are designated LAU-100(M)/101(M).

• The nose-fairing cavity is enlarged to provide sufficient volume for the larger AIM-9L/M umbilical. The AIM-9L/M umbilical uses a 34-pin connector versus the 19-pin connector that is used on the AIM-9B/E/J/P series. This larger connector requires more space in the forward nose fairing of the launcher rail.

• New spring-loaded canard retainers (with aerodynamic fairings) are added to the forward portion of the launcher rail. These retainers are required to hold the free-floating AIM-9L/M canards in a fixed position during captive carriage.

• An new-design umbilical retention hook is added in the nose fairing to accommodate the larger 34-pin connector required for the AIM-9L/M. The new umbilical retention hooks that are used in the LAU-100(M)/101(M) launchers have two positions: one for the AIM-9L/M and one for the AIM-9 J/P.

• The rail snubbers of the standard LAU-100/101 have been re-designed to be compatible with the AIM-9L/M.

Most fighter aircraft today are capable of carrying four (4) to six (6) AIM-9L/M missiles. The F-5 aircraft is an exception to this rule in that it is only certified to carry two (2) Sidewinders on the wing-tip stations. Operational analysis studies have shown that the combination of the high lethality of four (4) AIM-9L/M missiles with the agility and performance of the F-5 provides a substantial enhancement to the combat capability of the overall weapon system. Working in conjunction with the USAF Tactical Missile Technical Coordinating Group, TCA has developed a Quad Missile Carriage System (QMCS) modification kit that will allow the F-5 aircraft to carry four (4) AIM-9L/M Sidewinders.

The main impediment to adding two additional AIM-9 missiles to the F-5 in the past has been the unacceptable performance penalties that would result if these additional missiles were carried on the existing heavyweight, high-drag MAU-50 outboard pylons of the F-5. To counter this problem, TCA provides a new, low-drag, lightweight pylon (LDP) for the outboard station of the F-5 that is ideally matched to the characteristics of the AIM-9L/M.

F-5 Agility Enhancement Kit

improved manueverability

For customers that would like to improve the maneuverability of their F-5 aircraft, TCA has developed agility enhancement kits for the F-5 series that can be easily retrofitted.

All F-5 aircraft have included a wing-root leading edge extension (LEX) in their aerodynamic design. The original W1 LEX (designated by its wind tunnel model component number) was added to the F-5A/B wing design as a fairing over the leading edge flap actuator. Even though the W1 LEX was less than 2% of the wing area, it provided a 10% increase in the maximum lift capability of the wing, resulting in improved maneuverability. When the F-5E aircraft was developed, Northrop engineers increased the size of the LEX to approximately 5% of the wing area. This new LEX was designated W4 and provided a further 25% increase in maximum lift. Approximately 700 F-5E and 100 F-5F aircraft were delivered with the W4 LEX installed.

When the dual-seat F-5F was developed, it initially used the same W4 LEX as the single-seat F-5E. However, initial in-service experience with the F-5F uncovered some unfavorable stability characteristics at high angles of attack. In order to eliminate these problems, some design changes were made to the aircraft. The forebody was redesigned and new radome was developed that was designated “Shark Nose” due to its distinctive contour that resembled a shark. The wing flap control logic was changed to add angle of attack (AOA) as a scheduling parameter along with airspeed/Mach. The new flap system was designated “Auto Flaps”. One part of the design change resulted in a new, slightly larger LEX that was designated W6 LEX that is seen in the figure at the left. These three (3) design changes were certified by the USAF as the “Improved Handling Qualities – IHQ Package” and were incorporated in the production configuration of all F-5F aircraft built after 1979. For production commonality reasons (not to solve a stability problem), the IHQ package was incorporated into the production configuration of all F-5E aircraft after 1979 also.

Due to the fact that Northrop chose not to develop a retrofit kit for the IHQ package, none of the owners of previously delivered aircraft were offered the opportunity to upgrade their aircraft with the new design. In response to a market requirement from owners of F-5E/F aircraft built before 1979, TCA developed a wing leading-edge extension (W6 LEX) retrofit kit that is compatible with all configurations of the F-5E/F aircraft. The TCA W6 LEX kit is fully certified and is in daily operational service. The resigned shape of the W6 LEX provides a 10% increase in maximum lift over the W4 LEX. This increases instantaneous maneuverability, resulting in an improvement in mission effectiveness and survivability in close-in air-to-air combat. The W6 LEX also increases lateral-directional stability in the near-stall/post-stall angle-of-attack region resulting in improved spin resistance.

The benefits of the W6 LEX retrofit kit include:

• Increases instantaneous maneuverability at all subsonic Mach numbers by 10%, resulting in increased combat effectiveness in close-in air-to-air combat

• Increases lateral-directional stability in the near-stall/post-stall angle-of-attack region, resulting in improved overall departure and spin resistance

The Tiger Century W6 LEX retrofit kit is fully developed and qualified and is in series production. The installation kit includes step-by-step workbook instruction along with the required changes to the maintenance and Operational Technical Orders.