Naval Research Shows 3D Printing Makes JPADS More Accurate and Cost-Effective

The United States Army, Air Force, and Marines have been using aerial delivery systems (ADS) since WWII, so obviously 3D printed drones have major applications in the military – they’re not just for getting a pizza delivered. Another aerial tool that the military employs is a glider, which differs from a drone because it doesn’t require an engine to achieve free flight. The heavier-than-air glider works through the reaction of air against its lifting surfaces; a good example is the tried and true paper airplane. A glider system that is frequently used by the United States Marine Corps (USMC) is the Joint Precision Aerial Delivery System, or JPADS, which uses a GPS guidance system to fly over hostile territory for tactical air delivery resupply missions.

Recent advanced technology, like commercial-off-the-shelf (COTS) radio-controlled aircraft systems and 3D printing, have caught the eye of the military, as they could potentially use these advancements to help lower costs and increase accuracy of JPADS resupply missions. Lieutenant Chaz R. Henderson recently submitted a research paper, to help fulfill his Master of Science in Systems Engineering degree requirements from the Monterey, California-based Naval Postgraduate School, titled “Feasibility of tactical air delivery resupply using gliders.”

According to the paper’s abstract, “Due to the high host and logistical burden placed on deployed units by the Joint Precision Aerial Delivery System (JPADS), the USMC has requested proposals for a single-use tactical resupply glider that can resupply squads with 500 pounds of essential food and gear while costing less than $3,000 per unit and using commercial-off-the-shelf (COTS) electronics. The feasibility of this request was determined by designing, constructing, and testing two prototype gliding aerial delivery systems, Pun-Jet and Sparrow, using modern design and manufacturing techniques including AutoCAD, 3D printing, laser cutting and CorelDraw, and conducting field testing and subsequent analysis using MATLAB.”

The joint JPADS program began in 1997. Here’s how the JPADS actually works, according to a 2014 Defense Industry Daily article: the JPADS is dropped from high altitude, and uses a guidance, navigation and control system, coupled with GPS, to fly itself down to a pre-determined location on the ground. It’s able to land a ‘significant distance’ away from its release point, thanks to its gliding ram-air parachute, and the JPADS guidance systems allow for airdrops at either a single location or multiple locations at once. JPADS is able to provide navigational guidance for military teams being inserted overnight and to deliver leaflets and necessary supplies, and can also be used to deploy biological, nuclear, and chemical threat sensors.

The military has used other Precision Aerial Delivery Systems before, ranging from low glide systems to high velocity two-stage systems. Henderson’s research into JPADS offered a good opportunity to work on raising the accuracy of the system, as well as lowering the cost. While the JPADS is capable of multiple airdrop locations, it unfortunately jeopardizes the safety of small military units, because its ‘limited standoff range’ actually broadcasts their location to enemy troops. Also, due to the high cost per unit, re-use of the JPADS is necessary in order maintain fiscal responsibility. The overall objective of Henderson’s thesis was to use rapid prototyping and fast, cost-effective modern manufacturing techniques, like 3D printing, to construct gliding prototype airframes, as well as estimating the cost of these types of fielded systems and putting COTS electronic components through their paces, to test how viable they really are.

The prototype systems, flying wing design Pun-Jet and V-tail design Sparrow, were both made up of the same five components:

1. Airframe
2. Release mechanism
3. Automated guidance system
4. Delivery platform
5. Ground Control Station (GCS)

The automated guidance system was constructed using electronics that are common in radio-controlled airplanes, along with the PIXHAWK autopilot and GPS unit from 3DR‘s drone platform. The Arcturus T-20 UAV and the DJI Inspire quadcopter were used to take the two prototypes up to the proper altitude, where they were then released for testing.

The abstract of Henderson’s paper goes on to conclude that a low-cost glider-based precision aerial delivery system, using COTS electronic components, is very likely to be a good alternative to the current parachute-based systems, and can also reasonably be built using modern manufacturing techniques. It was noted that further research efforts should look into making the design even bigger, and improving both the navigation and landing algorithms in GPS-degraded environments, as research has not yet been conducted on what happens to the gliders in flight when the GPS signal is lost. Discuss in the JPADS forum at 3DPB.com.