Warship Technology: May 2017
DARPA’s SideArm research effort seeks to create a self-contained, portable apparatus able to horizontally launch and retrieve unmanned aerial systems (UASs) of up to 900lb. In December 2016, Aurora Flight Sciences successfully tested a full-scale technology demonstration system that repeatedly captured a 400lb Lockheed Martin Fury UAS accelerated to representative flight speeds via an external catapult. The system is capable of recovering aircraft up to 1,100lb, exceeding DARPA’s design objectives.
SideArm fits in the footprint of a standard 20ft shipping container for easy transport by truck, ship, rail, C-130 transport aircraft, and CH-47 heavy-lift helicopter. The small-footprint system is designed to operate in truck-mounted, ship-mounted, and standalone/fixed-site facilities. A crew of only two to four people can set up or stow the system in minutes.
SideArm owes its small size to combining its launch and capture equipment into a single rail that folds for transport. Rather than using a traditional capture method that uses a net to catch the UAS, the system snags a hook on the back of the vehicle and directs the hook to travel down the rail. This approach provides slower, more constant and controlled deceleration, which is safer for the vehicle.
Aurora Flight Sciences, which developed the SideArm, says it supports a range of fixed-wing unmanned aircraft. It states that it has an number of advantages, including a lower cost of operation compared to vertical take-off and landing systems and it can be installed on any ship with a helicopter flight deck.
“SideArm aims to replicate an aircraft carrier’s capability to quickly and safely accelerate and decelerate aircraft through a portable, low-cost kit that is mission-flexible, independent from local infrastructure, and compatible with existing and future tactical unmanned aircraft,” said Graham Drozeski, DARPA’s programme manager.
“We have demonstrated a reliable capture mechanism that can go anywhere a 20ft container can go. We are pleased with the progress we’ve made enabling a wide variety of sea and land-based platforms with intelligence, surveillance, and reconnaissance and strike capabilities from a UAS.”
SideArm is part of DARPA’s individual investment in Phase 1 research for Tern (see Warship Technology March 2017, page 17), a joint programme between DARPA and the US Navy’s Office of Naval Research (ONR). Now that demonstration of the capture system is complete, DARPA is working to identify potential transition partners and exploring using SideArm with other UAS platforms.
DARPA is also making progress with another unmanned aerial system project that envisions the use of large numbers of reusable unmanned aerial systems that could be launched and even retrieved in mid-air.
The agency recently completed Phase 1 of its ‘Gremlins’ programme, the Gremlins being the re-usable unmanned units. Taking the programme to its next stage, the agency recently awarded Phase 2 contracts to two teams, one led by Dynetics Inc in Huntsville, Alabama and the other to General Atomics Aeronautical Systems in San Diego, California.
“The Phase 1 programme showed the feasibility of airborne UAS launch and recovery systems that would require minimal modification to the host aircraft,” said Scott Wierzbanowski, DARPA’s programme manager. “We’re aiming in Phase 2 to mature two system concepts to enable ‘aircraft carriers in the sky’ using air-recoverable UASs that could carry various payloads.” Wierzbanowski said DARPA envisions an advance in unmanned aerial systems that would greatly extend the range, flexibility, and affordability ofUAS operations for the US military.
Phase 2 of the research effort seeks to complete preliminary designs for full-scale technology demonstration systems, as well as develop and perform risk-reduction tests of individual system components. Phase 3 goals include developing a full-scale technology demonstration system and conducting flight demonstrations involving airborne launch and recovery of multiple gremlins. Flight tests are currently scheduled for 2019.
The programme envisions launching groups of UASs from multiple military aircraft while out of range of adversary defences. When the gremlins complete their mission, a C-130 transport aircraft would retrieve them in the air and carry them home, where ground crews would prepare them for their next use within 24 hours. The gremlins’ expected lifetime of about 20 uses could provide significant cost advantages over expendable unmanned systems by reducing payload and airframe costs and by having lower mission and maintenance costs than conventional manned platforms.
