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Innovative Aerial Refueling Hose Stowage Methods

Description:

TECHNOLOGY AREA(S): Air Platform

OBJECTIVE: Develop an innovative packaging and/or construction method for stowing aerial refueling hoses that reduces the space required to stow the hose on tanker aircraft, while maintaining fuel flow and structural performance requirements.

DESCRIPTION: Aerial refueling (AR) is the process of transferring fuel from one aircraft to another during flight. The AR process enables important benefits beyond simply extending the range and the time the receiving aircraft can remain airborne, such as reducing fuel weight during takeoff, in turn, providing capabilities for shorter take-off rolls and greater takeoff payloads. The United States Navy (USN) primarily employs probe-and-drogue AR systems on its tanker and receiver aircraft. For organic carrier-based tankers, the USN utilizes the Aerial Refueling Store (ARS) 31-301-48310 or “buddystore” on the F/A-18 tanker, which is also a probe-and-drogue system. In these systems, a drogue is extended from the tanker on a length of refueling hose. The drogue provides stabilization and houses the reception coupling to which the receiver aircraft engages in flight. As new tanker and receiver aircraft come online, the need for longer hoses along with the need for more aerodynamic (lower drag) aerial refueling stores is forcing the USN to evaluate new methods of storing and extending the refueling hoses in tanker aircraft. The goal is to reduce the space required to stow the hose (which will allow more hose in a same space envelope or a smaller store design) while not negatively impacting fuel flow performance. The hose must be compatible with the USN ARS and the receiver end of the hose must be compatible with the coupling interface as defined in MIL-PRF-81975 [Ref 3].Key areas of performance to assess will be the ability to react/absorb the load during receiver engagements up to 10 feet/second and to handle the repeated stresses of extensions, retractions, stowage, and engagements. Current cycle requirement is 500 cycles without replacement. The system should include the ability to jettison (cut) the hose in flight as a failure mode. Fuel flow performance of up to 350 Gallons per Minute (GPM) (at 60 Pounds per Square Inch (PSI)) should not be impacted and should be assessed. The design should not increase fuel flow velocities to the point where surge pressure will exceed 120 PSI. Keeping velocities below 20 feet/second is generally accepted standard to minimize effects associated with static electricity. The proposer will develop an initial drawing package; and assess manufacturing plans and costs. The proposer may utilize the USN’s refueling probe impact test stand to conduct simulated engagements.The design and analysis produced should account for the full envelope of refueling conditions: Altitude: Sea Level to 30,000 Ft Airspeed: 180-300 Knots Calibrated Air Speed (KCAS) Environment: Day, Night, All Weather Receiver Engagement Speeds: 2 to 10 feet/second Structural requirements of MIL-H-4495 [Ref 2]

PHASE I: Design, develop and demonstrate feasibility of proposed concept for use on the existing USN “buddystore”. Validation should be in the form of modeling and simulation, and/or lab testing. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop the concept proposed in Phase I. Define a complete set of detailed design/performance specifications for the new system to use for validation. Build a full-scale prototype and coupon test articles to assess strength, fatigue, fuel flow/pressure, and hose reel operation and engagement performance. Hose jettison analysis should be refined and/or tested.

PHASE III: Mature testing in flight on a tanker aircraft. Conduct Receiver Engagements to demonstrate the complete envelope, and complete component qualification to ensure design is ready for the fleet. Perform testing and transition developed technology to appropriate platforms and end users. The commercial aerial refueling industry would benefit from successful technology development.

KEYWORDS: Aerial Refueling, Refueling Hose, ARS, Refueling Store, Rubber Hoses, Composite Hoses, Flexible Hoses

References:

1. “NATO Standard ATP 3.3.4.2, Air-to-Air Refueling Edition D, Version 1 April 2019.” https://standards.globalspec.com/std/13308207/ATP-3.3.4.2 2. “NPFC - MIL-H-4495 HOSE ASSEMBLY, RUBBER, AERIAL REFUELING (10 MAY 1985).” https://standards.globalspec.com/std/929286/MIL-H-4495 3. MIL-PRF-81975C, PERFORMANCE SPECIFICATION: COUPLINGS, REGULATED, AERIAL PRESSURE REFUELING TYPE MA-2, TYPE MA-3 AND TYPE MA-4 (22-JAN-2008)

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