Tech Briefs

AFRL Teams With Indy Racing League® for Neck Protection

The bulletlike, open-wheel Indy racing cars hurtle around oval tracks at breakneck velocities, often approaching speeds of 220 mph or higher. While a crash at this speed is a violent, sometimes tragic event, it is nonetheless a key data source for AFRL researchers seeking ways to create a safer environment for Air Force (AF) fighter pilots during emergency ejection.

Instituting a practical alliance of human peril and scientific research, AFRL engineers are teaming with the Indy Racing League (IRL) to share crash impact and injury data. Indy car drivers wear a miniature earplug accelerometer (see figure) that records vertical, lateral, and longitudinal accelerations of the driver's head during a crash. "This data will provide valuable information for criteria and model validation," states Ms. Erica Doczy, biomedical engineer in AFRL's Biomechanics Branch. "We need reallive human injury data to validate our models and criteria. In the lab, you can't re-create that [trauma], so this is just one way to collect that data, because accidents do occur in the motor sports industry."

The data helps researchers learn more about the dynamics of a highspeed impact and the effects of acceleration and impact on a human's head and neck. Researchers typically create models based on manikin and cadaver testing, but data from living humans is essential for validating the models. With the availability of detailed information about the car's speed and movement, and how the driver's head reacts at each stage of a crash sequence, researchers no longer have to theorize about the exact nature and cause of head and neck injuries. "We'll know what the car did, we'll know what the driver's head did, and we'll have medical data (the end result), so it's a way of validating the entire [series of] criteria," explains Dr. Joseph Pellettiere, technical advisor for the Biomechanics Branch.

The agreement with the IRL builds upon AFRL's long-standing program for improving neck protection for AF aircrew members during all phases of flight, and especially during high-risk, emergency ejection. "We develop the injury criteria and guidelines for how a flight helmet should be developed in terms of its mass properties—such as weight, center of gravity, and location of night vision goggles or other systems— such that it's safe for crew members to wear," elaborates Dr. Pellettiere.

AFRL researchers routinely feed updated data to flight helmet designers and manufacturers, who use the data to create safer next-generation equipment. The researchers also recommend the development and availability of preejection instructions that tell pilots how to physically prepare for ejection, including directions for assuming correct body position and bracing. "New helmet programs are using our criteria now," Dr. Pellettiere points out. "They are making their designs [according] to the guidelines we provide." Both the F-35 Joint Strike Fighter and the Panoramic Night Vision Goggle programs are developing helmets based on AFRL-supplied impact and injury data.

Indy car drivers benefit from the crash data through revised safety and equipment requirements which, in turn, improve racing safety levels. The research team also shares results with the commercial automotive industry through conferences and universities, a practice that can prompt safety-related policy changes for auto manufacturers.

As both technology and policy continue to evolve, the AF must persist in its efforts to evaluate pilot safety. This ongoing need is reflected in the following example, which illustrates how today's heavier helmet, coupled with a revised physical profile for pilots, has increased the risk of serious neck injuries during ejection. To accommodate a broader physical range of females (who currently constitute about 18% of AF pilots), the AF reduced the minimum body-weight limit for pilots to 103 lbs, with an associated decrease in neck muscle size and strength. Helmet weight, however, increases as peripheral systems are added to pilot headgear. A typical (3 lb) flight helmet's weight can increase to nearly 5 lbs after extra items, such as night vision goggles, are installed. According to Ms. Doczy, "Two additional pounds may not seem like much, but during an ejection, it adds a significant amount of force on the pilot's neck."

In addition to realizing safety improvements, the AF expects to achieve significant financial savings as a result of AFRL's neck protection advancements. "The potential for cost savings is tremendous, since the AF invests several million dollars to train each pilot," Ms. Doczy affirms. In addition to lost training dollars, the federal government bears the burden of an injured pilot through hospital and rehabilitation expenses. Preventing injuries and fatalities during ejection would minimize such costs. Cost-related advantages aside, the key goal for AFRL's neck protection program engineers— adeptly expressed in their motto, "Always Come Home Safely"—is to develop technology and use it to keep aircrew safe, not only during ejection, but ultimately in all phases of operational flight situations.

Mr. John Schutte (Ball Aerospace and Technologies Corporation), of the Air Force Research Laboratory's Human Effectiveness Directorate, wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at Reference document HE-H-05-04.

Posted in: Briefs, Medical

Scientists Create Optically Equivalent Synthetic Human Tissue

Lasers are an integral part of the modern battlefield, used for applications as diverse as point-to-point communications and ballistic missile defense. Their widespread use increases the warfighter's likelihood of being exposed to laser hazards, and damage to an individual's eyes and skin can be serious. AFRL has served as a leading authority on laser-induced damage thresholds for many years.

Posted in: Briefs, Medical

Dielectric Coolants

The Joint Strike Fighter (JSF) is the Department of Defense's affordable next-generation strike aircraft designed to meet the needs of the Air Force (AF), Navy, Marines, and US allies. Currently in development by Lockheed Martin, the multimission, supersonic, JSF aircraft will provide all services with enhanced lethality and survivability and reduced vulnerability (see figure). The JSF's unique, multiple-variant design pushes the threshold of fighter technology far beyond current limitations. The AF variant of the technology takes multirole fighter performance to new levels, offering improved stealth, increased range on internal fuel, and advanced avionics. The JSF's advanced avionics, as well as its flight control, target acquisition, and other sophisticated electronic systems rely on high-performance coolants to ensure proper operation. Designers employ dielectric coolants to dissipate heat from high-energy electronic components and therefore consider these fluids critical to aircraft operation and safety.

Posted in: Briefs, Materials

Weapon Data Link Demonstration

One of the US Air Force's goals is to reduce the time needed to strike timesensitive targets, thus minimizing the adversary's perceived mobility advantage and leaving concealment as that enemy's primary defensive measure. One potential way to meet this challenge relies on a capability to redirect and update weapons with new target coordinates while they are in flight—a solution that requires weapons developers to outfit weapons with a data link enabling communications between warfighters operating in the air and on the ground. This Weapon Data Link (WDL) approach would allow the warfighter to directly communicate with and control air-launched weapons to strike moving or otherwise time-sensitive targets, while continually gathering information about the weapon's performance against those targets. The scenario could involve something as simple as a weapon communicating its position and system status back to the release aircraft, or something as complex as a weapon operating in the Global Information Grid (GIG), wherein a secondary ground/air controller assumes the weapon's control after a positive handoff from the release platform, with the weapon's sensor and video information autonomously distributed throughout the GIG.

Figure 1. Depiction of WDLAFRL engineers recently accomplished a critical step in demonstrating the WDL approach. Held at Langley Air Force Base (AFB), Virginia, the demonstration's primary objective was to show that two WDL terminals, connected to Tactical Air Control Party (TACP) laptop computers, could successfully transmit and receive J-series messages within a Link-16 network (see Figures 1 and 2). The network included a legacy Fighter Data Link (FDL) terminal provided by the 46th Test Squadron (Eglin AFB, Florida), two WDL terminals, and local aircraft equipped with Link-16 radios.

Engineers from AFRL and Rockwell Collins partnered to develop the 50 in3, software-defined WDL radio used in the demonstration. This radio provides multiple operators with the flexibility to port and upload communication waveforms. The device has three software waveforms loaded into its memory; the operator can switch between these waveforms as required. Although the test team limited this demonstration to Link-16 operation, future demonstrations will highlight the radio's capacity to receive and transmit ultra-high-frequency satellite communications and line-of-sight waveforms as well. The TACP Modernization program supplied the TACPCASS (Close Air Support System) software, laptop computers, and a trained operator. During the first part of the demonstration, one TACP computer generated target coordinates and transmitted them as J-series messages from one WDL terminal to the other. The TACP-CASS software on the second TACP computer interpreted and displayed the transmitted messages as target tracks. This test showed that messages generated by the TACP-CASS software could be correctly interpreted by the two networked WDL terminals and that this information could be shared between them. In the second phase of the demonstration, test engineers integrated the FDL terminal into the network. One of the TACP computers transmitted target information via Link-16 network protocol to the FDL terminal, which correctly interpreted and displayed the information on the Improved Multilink Translator and Display System (IMTDS). In the next phase, both computers correctly received, interpreted, and displayed target messages transmitted by the FDL terminal. In a final demonstration of system capability, several aircraft from Langley AFB joined the network for short periods of time, transmitting information that was subsequently displayed on both the TACP and IMTDS computers.

Figure 2. Setup of WDL demonstration equipmentAll demonstration participants gained valuable insight into using Link-16 networks for passing J-series messages between aircraft, weapons, and ground troops. The test team did not intend for the demonstration to provide an in-depth look at integrating weapons into battlefield networks. Rather, its purpose was to provide a rudimentary understanding of how an aircraft, weapon, and TACP could join and operate in an existing Link-16 network, while specifically demonstrating the capability of a software-defined WDL radio to transmit and receive J-series messages. The demonstration achieved its twofold purpose, both providing overall insight regarding the system and establishing the flexibility of a softwaredefined WDL radio in processing J-series messages within a representative network.

Ms. Michelle White, of the Air Force Research Laboratory's Munitions Directorate, wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at Reference document MN-H-05-14.


1 "China-America: The Great Game." Interview With Lt Gen Liu Yazhou. Eurasian Review of Geopolitics, Gruppo Editoriale L'Espresso/Cassan Press-HK, Jan 05.

Posted in: Briefs, Electronics & Computers, Data acquisition and handling, Personnel, Military aircraft

RASCAL Facility

AFRL's Radiation and Scattering Compact Antenna Laboratory (RASCAL) enables researchers to develop and evaluate advanced aperture technologies that support electronic warfare, radar, communication, and navigation— technologies supplementing a variety of applications as the "eyes and ears" of the warfighter. Current research efforts are concentrated on developing relatively small and inexpensive broadband, multifunctional antennas, as well as conformal and structurally integrated antennas for manned and unmanned air vehicles. Using the RASCAL facility, researchers can perform the necessary fabrication, simulation, testing, and measurement of aperture technologies.

Posted in: Briefs, Electronics & Computers, Antennas, Test facilities, Military aircraft

Response Surface Mapping Technique Aids Warfighters

When weaponeering a target, military planners pinpoint a detonation location that will result in the desired damage to the entire target, or even a particular area within the target. The warfighter then selects the most suitable delivery platform— aircraft, weapon, guidance package, release altitude, and speed— for inflicting the appropriate damage to the target. Determining the proper combination of variables capable of producing the desired effect on a hardened target requires the warfighter to understand the penetration dynamics of the weapon; it also relies on the individual's ability to adjust the variables within his or her control, as necessary. For a scenario in which the destruction of a specific target is often coupled with the mitigation of collateral damage, it is imperative that the warfighter make proper decisions regarding weapons selections. AFRL scientists, collaborating with other Department of Defense agencies, applied innovative data mining and visualization methods to aid warfighter efficiency and effectiveness in making these choices.

Posted in: Briefs, Information Technology, Cartography, Data acquisition and handling, Imaging, Terrain, Military vehicles and equipment

Microelectromechanical Systems Inertial Measurement Unit Flight Test

AFRL and Boeing engineers conducted successful flight tests of microelectromechanical systems (MEMS) inertial measurement units (IMU) on the Joint Direct Attack Munition (JDAM). They collected flight data and validated the MEMS IMU technology's capability to provide stable navigation performance and accurate weapon guidance, both with and without Global Positioning System (GPS) updates. Researchers will use this flight data to further refine MEMS IMU technology to enhance future capabilities of air-launched munitions.

Posted in: Briefs, Mechanical Components, Microelectricmechanical device, Navigation and guidance systems, Flight tests