TECHNOLOGY AREAS: Air Platform, Sensors, Space Platforms

ACQUISITION PROGRAM: PEO(JSF), PEO(w)-Advanced Development and Aerial Refueling Program Offices

OBJECTIVE: Develop innovative technology that can stabilize/control the motion of an aerial refueling (AR) drogue in flight.

DESCRIPTION: Stabilized drogues will be a critical component to future automated probe and drogue refueling systems, including refueling with unmanned receiver aircraft. In addition, manned receiver aircraft, like the Joint Strike Fighter (JSF), will benefit greatly from stabilized drogues by reducing pilot workload and the inherent risk associated with AR. This technology should be adaptable to existing USN/USAF probe and drogue air refueling systems.

Probe and Drogue refueling takes unique piloting skills to accomplish. Maneuvering a 4 inch diameter probe into the center of a 2 foot diameter drogue (aluminum coupling and basket with a fabric canopy added for lift/stability), at closure rates of up to 10 feet/second, is no easy task in the best of conditions. Turbulence, tanker navigation and wake, and receiver forebody affects all degrade the stability of the target presented by the refueling drogue. Being able to control the drogue oscillations and present a more stable target to the receiver would greatly benefit the war fighting capabilities of all probe equipped receivers, worldwide. This would reduce mishaps, decrease costs and foreign object debris (FOD) associated with drogue wear/damage, and reduce the time of a refueling evolution, yielding an improved mission effectiveness for the JSF, other manned receivers, and unmanned aircraft.

In addition to supporting conventional aerial refueling missions, this technology may be critical to development of unmanned receivers which require some method to track the drogue in order to perform the refueling operation. Contact with the drogue is only safe and effective when the drogue position is stable. To enable reliable, repeatable and safe autonomous refueling, as well as workload reduction for manned refueling, a drogue stabilization and control method is required.

The need for drogue control is defined as the capability to position the drogue at a specified stabilized location relative to the tanker, despite the presence of turbulence, airwake, receiver forebody and other effects. This is especially important for unmanned applications, as the ability to steer the drogue to a specific location may greatly simplify or eliminate the receiver�s requirement to track the drogue. It is desired that the capability be as cost-effective as possible to implement on the tanker/drogue system, with no impact to the receiver. This is significant for low-observable aircraft, where the installation of AAR-specific sensors on the receiver is problematic.

Development and fielding of controllable drogue technology has potential to positively impact every probe equipped platform in the US and worldwide military, in addition to future unmanned autonomous vehicles. While identification of the specific tanker platform limitations is important to the design of each individual solution, the transfer of this technology from one hose and drogue system to another should be a relatively simple adaptation due to the similarity of the refueling drogues used on USN/USAF refueling systems. Special emphasis will be placed on the technical approaches which are most adaptable, common, and interoperable among the range of hose/drogue refueling systems in use. In addition, the maximum amount of interoperability and commonalty is desired between proposed controllable drogue solutions and technology under development for boom-receptacle refueling.

PHASE I: Develop concepts for stabilization and control of Aerial Refueling Drogues. Demonstrate feasibility of the approach through analyses, modeling and simulation, along with limited validation on scale models. Analysis will include simulation of sensing/positioning systems, feedback/control techniques, aerodynamics, tanker and receiver dynamics, system errors, environmental conditions, unit cost and reliability estimates, and other appropriate factors. Engineering drawings/3-D modeling should be at an acceptable stage so as to facilitate prototype construction in Phase II. Sufficient understanding of aerial refueling limitations and specifications should be demonstrated in order to add to credibility of design. The targeted tanker aerial refueling system(s) will be identified, along with the specific requirements of that system.

PHASE II: Develop a working prototype with sufficient analysis and testing (flight and/or ground) to prove that the prototype is ready for a developmental flight test program. Modeling and simulations/analysis should be refined as a result of Phase II testing and documented to the point where it can be used as risk reduction for developmental testing. Developmental testing phases may include testing on a manned aircraft/ unmanned surrogate receiver with the eventual goal to support testing with an unmanned autonomous receiver.

PHASE III: Transition the prototype stabilization and control system to the government for developmental and operational flight testing along with fleet implementation.

PRIVATE SECTOR COMMERCIAL POTENTIAL.DUAL-USE APPLICATIONS: The commercial tanking industry would benefit from the development of this technology. This is a growing industry that uses contractor owned aircraft to provide aerial refueling services to the military and military support contractors.

REFERENCES: 1. MIL-A-19736A, Military Specification for Aerial Refueling Systems

2. MIL-A-8865B, Military Specification Airplane Strength and Rigidity Misc. Loads

3. MIL-C-81975B, Military Specification, Coupling, Regulated, Aerial Pressure Refueling

4. Joint Service Specification Guide, 2001 and 2009 Appendix F; STANAG 3447.

KEYWORDS: Aerial; Refueling; Automated; Controllable; Drogues; Stabilized

TPOC: (732)323-4058
2nd TPOC: (619)545-0959
3rd TPOC: (301)342-2632

** TOPIC AUTHOR (TPOC) **

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