Buddy refuelling with a boom
September 9, 2024
The US Air Force faces a critical shortfall in forward air-to-air refuelling capacity. Longer ranges in the Pacific will increase the demand for tankers, just as China’s expanding A2/AD capabilities force traditional tankers to stand off ‘further back’. One answer is ‘buddy refuelling’ with smaller tactical aircraft carrying refuelling pods to top up the tanks of their wingmen. Until recently, buddy refuelling pods have been limited to ‘probe and drogue’ operations, and have been unsuitable for use by receptacle-equipped USAF receivers, which have traditionally needed a large tanker equipped with a rigid refuelling boom.
The US Air Force has recently awarded contracts to two companies for work on Small Hybrid Aerial Refueling Kit (SHARK) podded aerial refuelling systems that are compatible with aircraft that use the boom method to refuel in flight. The Air Force Research Laboratory (AFRL) awarded Legionnaire International a $3,193,251 contract for Small Hybrid Aerial Refueling Kit (SHARK) work on 27 August, and placed a separate $2,677,093 SHARK contract with Leidos subsidiary Dynetics two days later.
The two SHARK contract award notices describe a “small form factor fuel transfer mechanism that fits inside of a modular, platform agnostic, podded, outer mold line,” and are understood to be related to the Air-to-Air Refueling Mechanism (A2RM) Digital Design Challenge announced by AFWERX (part of AFRL) last year. This aimed to “leverage recent technological advancements in automated aerial refuelling to modernize fuel transfer systems for smaller, more flexible refuelling capabilities,” with an initial focus of designing a system for use on the F-15.
“These new systems will enable the USAF to perform tactical refueling missions akin to the United States Navy’s (USN) buddy tanking, enable automated aerial refueling capabilities, and provide flexibility for mission planners & joint strike packages, to name a few. … The capability is primarily intended to refuel medium to small ‘fighter’ sized aircraft.”
A2RM called for a platform agnostic “podded” and “internally stowable” system that would stow within the carrier’s Outer Mould Line, and that would be “capable of a boom/receptacle refuelling (at a minimum), with a desire for dual boom/receptacle and probe/drogue refuelling.” There were suggestions that a system should have a 36-inch diameter and a 230-inch length to enable it to fit inside a modified 600-gallon drop tank, with an aspiration to perhaps design an even smaller system able to fit within a 330 gal external fuel tank which is “more universally used across USAF & USN.”
The A2RM challenge was also aiming to study “solutions that stow their own fuel, solutions that receive fuel from host aircraft, and [was] especially interested in capabilities that can do both.” One A2RM graphic showed a notional gondola-mounted system with a retractable refuelling boom that could be belly-mounted under a business jet, twin-engined airliner or / various tactical combat air platforms.
The challenge envisaged the use of existing, fielded refuelling technology (relative navigation sensors, pumps/valves, automation, station keeping systems, etc. leveraging technology that could be matured and integrated no later than Fiscal Year 2026.
