The Army Nearly Adopted This Stealthy OH-58X Kiowa Warrior Variant

The U.S. Army wants a new high-speed, long-range, stealthy attack reconnaissance helicopter to finally succeed the OH-58D Kiowa Warrior scout helicopter, which the service decided to retire prematurely in 2014. The service says it needs the new helicopter to meet the operational demands of a potential high-end conflict with a “great power” adversary, such as Russia or China. With all this in mind, it’s interesting to remember that the Army had at least a smaller number of Kiowas with various stealthy features, known as the OH-58X, nearly thirty years ago.

Secretary of the Army Mark Esper underscored the importance of the Future Attack Reconnaissance Aircraft (FARA) program to the service’s overall modernization goals during a press conference at the Pentagon on Apr. 17, 2019. He also highlighted work on new long-range artillery, air and missile defenses, heavy armored vehicles, and communications and data sharing networks. The Army says it has made cuts to more than 90 existing programs to free up funding to support these efforts and Esper, along with other senior officials, has faced criticism from Congress and others over many of these decisions.

“What I don’t have right now is an attack reconnaissance aircraft,” Esper told reporters. “That’s what I need to penetrate Russian or Chinese air defenses.”

The Army’s plan is for whatever design wins the FARA competition, the first phase of which will begin this year, to replace AH-64 Apaches in the Army’s Attack Reconnaissance Squadrons. This represents roughly half of the total number of these gunships that the service has at present.

These units emerged after the Army retired the OH-58D Kiowa Warrior, ostensibly due to the budget reasons, with the last of those scout helicopters finally leaving the service in 2017. The Army has been without a true replacement ever since.

An OH-58D Kiowa Warrior, in front, flies with an AH-64 Apache., US Army

“The Apache is the best attack helicopter in the world, but it’s not the best armed reconnaissance helicopter,” U.S. Army Brigadier General Walter Rugen, head of the Future Vertical Lift (FVL) Cross-Functional Team (CFT) within the new Army Futures Command, told Aviation Week earlier in April 2019. “We need a smaller form factor that can hide in the radar clutter and that has reach.”

Previous attempts to replace the OH-58Ds directly, which led right to the ultimate decision to retire the helicopters entirely, suffered from repeated missteps and mismanagement, becoming its own saga, which you can read about in more detail here and here. The Army had, of course, also expected to have replaced the Kiowa Warriors with the RAH-66A Comanche stealth helicopter in the mid-2000s, before canceling that program, which had ballooned in cost and suffered serious delays, in 2004. 

It is also important to note that the service had been very interested in the idea of stealthy helicopters for decades before Comanche and had invested heavily in related research and development before that particular program started. As early as 1978, Sikorsky had produced a detailed report on low radar cross-section fuselage concepts for its then still relatively new UH-60A Black Hawk.

But, had things gone differently, the Army might have already been flying the advanced OH-58X years before the Comanche program came to a close. The origins of the X model in many ways actually trace all the way back to the service’s decision to buy the original OH-58A Kiowa in 1967.

Two years earlier, the Army had chosen the Hughes OH-6A Cayuse to be its new scout helicopter, passing over Bell’s YOH-4, the progenitor of the Kiowa and its commercial Model 206 Jet Ranger.

Bell’s YOH-4A during tests in the early 1960s., US Army via Ray Wilhite

As it turned out, Hughes had grossly overstated its production capacity and the Army turned back to Bell and the Kiowa to fulfill its requirements. The OH-58As, as well as improved OH-58Cs with its more powerful engine and other updates, outlasted the Cayuse in regular Army use.

However, the Cayuse, and further improved variants of the Hughes design, commonly known as Little Birds, found a second life in the Army’s burgeoning special operations aviation community in the 1980s. AH-6 light attack helicopters and MH-6 light transports quickly became a core component of what eventually became known as the new 160th Special Operations Aviation Regiment, also known as the Nightstalkers.

One of the 160th Special Operations Aviation Regiment’s MH-6 Little Birds equipped with side-mounted planks for special operators to ride on during insertions and extractions., US Army

At the same time, the Army was experimenting with various light, rapidly deployable unit concepts that would also leverage state-of-the-art technology to help keep them viable against a more robust opponent. An Army test force emerged known first as the High Technology Testbed (HTTB), then the High Technology Light Division (HTLD), and finally as the 9th Infantry Division (Motorized).

Over more than a decade, these organizations evaluated all sorts of different vehicles, weapons, and equipment, including, but hardly limited to heavily armed dune buggies, light tanks, ground-launched AGM-114 Hellfire missiles, and ultra-light aircraft. In the course of this experimentation, the question of what kind of helicopters a rapidly deployable light force might use also came up.

The original plan was to acquire Little Birds to support the force. This made good sense since the 160th was already demonstrating concepts for rapidly moving these small helicopters to forward locations, even in austere environments, and quickly establishing aviation operations at those sites. But the Army rejected those requests.

A much more recent picture of members of the 160th Special Operations Aviation Regiment unloading an AH-6 Little Bird from an MC-130 special operations transport aircraft., DOD

Instead, the Army’s high-technology test force managed to acquire a number of JOH-58C Light Combat Helicopters (LCH). The Army had modified these Kiowas for the 160th, but that unit had rejected them in favor of the JOH-6A LCH. The JOH-6A eventually got redesignated as the AH-6C and became the first of the Nightstalkers’ armed Little Birds.

The JOH-58Cs received additional modifications as part of the high-technology testing, including one extreme example with a three-barrel 20mm M197 cannon mounted in the co-pilot’s seat and firing out through the helicopter’s nose. This proved to be impractical and dangerous, since firing the gun could fill the cockpit with residential propellant gasses that could choke and blind the pilot.

The JOH-58C with the M197 cannon installation., US Army via Ray Wilhite

Another example, with the serial number 70-15349, served as a surrogate for an advanced configuration known as the OH-58X. In 1985, the Army’s Aviation Engineering Flight Activity conducted limited airworthiness and flight characteristics testing of this particular helicopter. This initial OH-58X surrogate did not have any stealthy features, though it did contain a number of other advanced systems, many of which the Army obtained commercially.

This included a new stabilization and control augmentation system (SCAS) from French avionics firm SFENA, a Direct View Optics (DVO) roof-mounted sight from Ferranti in the United Kingdom, and an unspecified roof-mounted, turreted forward-looking infrared (FLIR) sensor. The DVO, the same model used on some French and British Aérospatiale Gazelle light scout helicopters, had a laser designator, which would have given the OH-58X the ability to fire Hellfire missiles.

The JOH-58C configurated as the OH-58X surrogate., US Army via Ray Wilhite

70-15349 also carried over various modifications from its original life as a possible special operations platform. This included modified landing skids that could collapse to lower the helicopter’s overall profile, as well as folding tail assembly, all to make it easier to load and unload the helicopter from a cargo aircraft. It also had the improved tail rotor assembly found on Bell’s Model 206L-3 Jet Rangers. Lastly, there were range-extending fuel tanks and added communications and navigation gear.

The Aviation Engineering Flight Activity reported that the helicopter had significantly improved performance over a standard OH-58C, but that it was also more complicated to fly, especially at lower speeds. The test pilots recommended modifications to the SCAS and to alert pilots to potential limitations in certain flight regimes until the helicopter received further upgrades to fully mitigate these issues.

That didn’t happen. Separately from the high-technology testing, the Army had also initiated an Army Helicopter Improvement Program (AHIP) to modernize its Kiowas in 1981. AHIP led directly to the introduction of the OH-58D in 1985. The OH-58D, also known as the Bell Model 406, was a significantly more powerful design with an improved four-bladed main rotor. 

The helicopters also eventually gained a mast-mounted sighting unit with electro-optical and infrared cameras, as well as a laser designator. The Army ultimately bought hundreds of new OH-58Ds and converted older Kiowas to this new standard. The first armed examples, sometimes referred to as AH-58Ds, entered combat for the first time in January 1988 as part of Operation Prime Chance. Flying from U.S. Navy ships in the Persian Gulf, the helicopters engaged against Iranian boats threaten U.S.-flagged oil tankers sailing through the region.

An OH-58D Kiowa Warrior., US Army

The OH-58X effort, which was certainly duplicative of AHIP in many ways, threatened to compete for funding and other resources with the OH-58D program. The Army ultimately canceled the OH-58X project in favor of the Kiowa Warrior.

But the idea of an even further advanced OH-58, now based on the D model’s more powerful design didn’t go away. Bell eventually took a Kiowa it had converted to the OH-58D configuration, serial number 69-16322, and turned it into a new OH-58X demonstrator with a major focus on stealthy features.

The new helicopter had a chiseled nose profile, making it visually distinct from a standard OH-58D. Bell replaced the “doghouse” on top where the engine and main gearbox sat with one made of a radar absorbent material, according to a 1992 Flight International article. The design also included radar-absorbing “cuffs” on the main rotor mast and hub and on the tail rotor assembly. The rotor blades, mast-mounted sight, and skids all received a special coating to reduce their radar reflectivity.

A low-quality image of the OH-58X demonstrator. Note the chisel nose and the “cuffs” on the main rotor to reduce its radar signature., US Army

The configuration “works extremely well,” Jack Gallagher, Bell’s OH-58D program manager at the time, told Flight International. It “performs [against known threats] better than anything out there.”

Bell also pitched it as a cost-effective conversion for existing Kiowa Warriors, claiming each stealth kit would cost just $200,000, less than $365,000 in today’s dollars. In 1992, the flyaway cost of a new OH-58D was $6.7 million, or the equivalent of more than $12 million today.

Another picture of the OH-58X demonstrator, but without the “cuffs” installed on the main or tail rotors., Bell via

This was an important selling point for the U.S. Army, which, as already noted, had been very interested in a stealthy light scout helicopter to completely replace all of its OH-58s since the early 1980s and had been investing heavily in research into stealth helicopters, in general, years before that. The stealthy scout helicopter effort, known as the Light Helicopter Experimental (LHX) program, had itself spawned the Advanced Composite Airframe Program (ACAP), which involved experiments with two different helicopters – Bell’s D-292 and Sikorsky’s S-75 – with composite airframes to reduce their radar signatures.

But by 1991, when the Gulf War started, despite all of the Army’s investments, none of these projects had yielded an actual production-ready design, at least publicly. So the service turned to Bell, which reportedly modified 18 OH-58Ds into the X configuration for operations in Southwest Asia, but they arrived too late to see action against Iraqi forces, according to Flight International.

An OH-58X in US Army colors., Bell via Flight Global

As of January 1996, the stealth kits were still in storage and available for use, if necessary, according to Army, the official publication of the Association of the U.S. Army. At that time, Bell was reportedly still working on improving the stealthy configuration.

It’s not entirely clear what happened to these remnants of the OH-58X program in the end. The War Zone reached out to the U.S. Army Aviation and Missile Command’s history office, but they said they could not find any specific records about the final status of the project. Bell’s public relations team similarly said that there did not appear to be any additional information beyond what the company had shared publicly in the past, but added that some details might remain classified.

It seems very possible that defense budget cuts in the years following the collapse of the Soviet Union may have killed the OH-58X for good, in favor of LHX, which evolved into the Light Helicopter (LX) program and led to the selection of Boeing and Sikorsky’s RAH-66A design in April 1991. The Army had touted Comanche as a stealthy Kiowa replacement, making it easy to see how it could have subsumed the OH-58X project. But the RAH-66A was also significantly more advanced and capable than the Kiowa, with various features, especially its armament package, that were more in line with an attack helicopter, such as the AH-64.

In something of a throwback to the original JOH-58C LCH concept, in 1992, Bell had also introduced a non-stealthy Multi-Purpose Light Helicopter kit, which featured similar “squatting” landing skids to reduce the helicopter’s overall height. Sometimes referred to as the UH-58E, this configuration also had a cargo hook under the fuselage for carrying small loads slung below, as well as mounts on either side of the fuselage to fit external platforms for carrying cargo, wounded personnel on stretchers, or inserting and extracting special operations forces. This arrangement was similar in general concept to the planks on the 160th’s MH-6 Little Bird light transports.

Bell says that the Army purchased dozens of MPLH

kits, but rarely used anything besides the landing skids. There are various pictures that show OH-58D Kiowas over the years with the MLPH skids, but there does not appear to be any photographic evidence of the service using any other part of that kit operationally.

An OH-58D Kiowa Warrior with the MPLH skids in Iraq in 2004., US Army

Whatever the case, the Army shifted its stealth helicopter focus to Comanche for more than a decade, before canceling that program in 2004. The War Zone has previously explored in depth how the service may have been able to keep the stealth helicopter brain trust alive in the classified domain, helping to produce such things as a stealthy UH-60 Black Hawk transport helicopter. The existence of this Stealth Hawk became public in 2011, when one of them crashed during the raid that led to the death of Osama Bin Laden in Abbottabad, Pakistan.

However, the stealthy Kiowa seems to have faded into obscurity. When the Army looked into upgrading the OH-58Ds to new OH-58F configuration in the early 2010s, there were no stealth features as part of the package.

The OH-58F prototype., US Army

The Army has now come back around to the idea of a stealthy attack reconnaissance rotorcraft with the FARA program. The service’s requirements also demand a design with a top speed of at least 230 miles per hour – nearly 100 miles per hour faster than the Kiowa Warrior – and greatly extended range over previous scout helicopters. Beyond stealth features, this next generation attack reconnaissance platform will also have a robust electronic warfare suite to detect and jam enemy radars and other cutting-edge defensive systems.

The Army says it will announce the companies that will take part in the first phase of the FARA program this year and it hopes to down-select to just two competitors in 2020. There will then be a fly-off between the two, leading to the selection of a final winner in 2024.

So, while the Army may have largely passed over OH-58X, it may finally get a helicopter with far higher performance and that is more survivable and stealthy than the Kiowa Warrior could ever have been.

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