Military, Products, Regulatory

Military Spin: Revolutionary Technology for SAR

By Steve Colby | November 1, 2007

SINCE SAR IS A MISSION THAT HAS had many years to mature, it’s uncommon to see revolutionary changes that improve helicopter mission execution. But several technologies and one organization in particular show remarkable promise.

Their improvements range from aircraft design to satellite-based mission dispatch and self-protection.

In my opinion, the helicopter technology that shows the greatest promise for revolutionizing SAR is the Piasecki Aircraft Corp. vectored-thrust ducted propeller (VTDP) compound helicopter project, whose aircraft began flight tests June 29. Historian Earl Tilford wrote that in the Vietnam War we needed a helicopter with the power, speed, and range to provide necessary SAR coverage for the theater. Today’s requirements show we need a platform that can fly fast (more than 200 kt indicated airspeed) and perform as well as an advanced helicopter in high/hot hover conditions.


The ducted propeller demonstrates compound-helicopter technology in a full-scale version without the compromises in hover performance shown by other rotorcraft configurations. This technology promises to enable significantly higher speeds than conventional helicopters due to several factors.

First, thrust is provided by the ducted propeller, removing the significant performance penalty of cyclic-produced thrust in conventional single rotors. Secondly, lift will be transferred from the rotor to the fixed wings in forward flight, delaying the onset of retreating blade stall. Lastly, reduced rotor rpm at higher speeds will prevent transonic Mach compressibility on the advancing-side blade tips.

With its retractable, clamshell-like duct, anti-torque performance in a hover is very similar to conventional or Fenestron tail-rotor performance.

This technology is scalable for differing military mission sets, including medevac, combat SAR, attack, reconnaissance, and border patrol. It is applicable as a potential upgrade to many single- and even tandem-rotor helicopters, reducing development cost and time, and making it affordable to field.

For civil mission sets, the technology is ripe for SAR, EMS, commuter and VIP transport, and offshore support.

Speed into action, hover performance at the objective, and recovery time are key lifesaving and money-making elements in the helicopter business. VTDP compound-helicopter technology brings remarkable advances in all these areas. Kudos to Piasecki, the U.S. Naval Air Systems Command and the U.S. Army’s Aviation Applied Technology Directorate for aggressively pursuing this technology.

Another technology that will significantly change the way we operate is satellite based-dispatch/tracking systems. With high-fidelity situational awareness on both the operator and dispatch ends, these data links offer efficiencies that the astute reader will recognize as beneficial to SAR, EMS, police, border patrol, corporate, offshore, and military operations. While they won’t produce power for the hover, they will produce the power of knowledge in the age of information.

Building operator instantaneous situational awareness of the objective, whether it be picking up a patient with injury information in the data-link dispatch, finding an illegal border incursion with John Madden-like digital-map pointers, or dispatching the closest SAR-capable helicopter in a mass-casualty disaster from a data-linked operations center, the benefits for helicopter operations haven’t been scratched as yet. But the potential is clear.

The last technology that shows the greatest promise to save military helicopter crew lives in the age of infrared missiles is turreted, directed IR jammers. Integrated with missile warning and flares systems, this technology cleverly locates, declares, and jams inbound IR-guided missiles with precisely aimed, pulsed laser energy. These systems have already saved many lives in combat. Leverage this detection-technology concept toward hostile fire indications and you create a technology that will paint crews a "point of origin" picture for bullets, rocket-propelled grenades, and other projectiles fired in their direction. Determining whence unseen ground fire comes and proper defensive maneuvers are the hardest parts of surviving a tactical small-arms engagement. Enabling crews to safely avoid that fire would constitute a huge improvement in combat survivability. Developers are working on concepts to defeat and counter incoming ground fire. While the technology is very complex, this could greatly help with combat helicopter survival.

Lastly, the organization that I believe has made the most ardent strides in improving SAR process capability is the Helicopter Assn. International. Its leaders have ponied up the bodies and effort to compile a first-responder database of SAR-capable civil and public-agency helicopters. I have recommended for years in this forum that civil planners work with military agencies to build databases of regional military helicopter support capability. HAI recognized the need, collected the capabilities, and built the database for civilian counterparts. Kudos to HAI for its efforts on our society’s behalf. It’s a step that the military should emulate and provide to regional first-responder emergency planning cells.

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