Bell ARH-70 (Arapaho)
Armed Reconnaissance Light Helicopter
The Bell ARH-70 was in line to replace the aging OH-58D Kiowa Warrior series of light armed reconnaissance helicopters for the US Army before the project saw cancellation.
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The Bell ARH-70 helicopter was developed for the US Army as a possible direct replacement to the successful but aged Kiowa Warrior series of light armed reconnaissance mounts. In an effort to keep production and acquisition costs down for the US Army, the project attempted to develop a product using existing yet proven components. The Bell ARH was born from this requirement and was essentially a militarized form of the successful civilian-minded Bell 407 product. The new helicopter system shared a visible resemblance to the OH-58D Kiowa Warrior it intended to replace. The ARH-70 came about from the US Army's Armed Reconnaissance Helicopter (ARH) program after the official cancellation of the stealth-minded, two-seat RAH-66 Comanche light attack helicopter. Initial production forms would have been given the designation of ARH-70A.
The RAH-66 Comanche
The RAH-66 Comanche proved something of an embarrassment for the US Army. Development of this platform had now stemmed multiple decades with little to show for the endeavor. It was reasoned (and rightfully so) that continued support of the program - as promising as it may have been on paper - was to only skyrocket financially beyond scope. As such, the fledgling program was axed in 2004 in favor of upgrading existing fleets of still-viable platforms such as the OH-58D Kiowa Warrior or the MH-6 "Little Bird".
The Call Goes Out
In December of 2004, the requirement was sent out by the US Army and interested parties responded with their proposals. Chief among the returns was the Bell Model 407 (billed as an upgraded OH-58 Kiowa Warrior) and a Boeing response (essentially an upgraded MH-6 "Little Bird"). Bell eventually won out and was awarded the multi-billion dollar production contract on July 29th, 2005. The contract called for some 368 production examples and required two prototypes along with two preproduction samples, this later changed to require four pre-production worthy examples instead.
First flight of a demonstrator ARH was achieved on June 3rd, 2005. Further flights ensued and ultimately included additional avionics, mission-specific systems and the selected Honeywell HTS900-2 series turboshaft engine. The engine was trialed only on demonstrators and on the ground to verify its base qualities to this point. After some program delays, the first "true" ARH-70 prototype (Prototype #2) went airborne on July 20th, 2006, less than one year since the awarding of the Army contract. Prototype #4 was of note for it was forced to make a crash landing at a gold course after suffering an engine failure, this recorded on February 21st, 2007. Though neither of the pilots was harmed in the crash, the airframe was deemed a complete loss and a setback for the ARH program.
Ultimately, delays and product costs soon crept up on the ARH-70. The US Army halted the project for the time being, giving Bell one month to get its act in order. For the interim, Bell used its own money to further develop the systems until the US Army agreed to pick up the project once again by the middle of 2007. The rising costs forced an automatic and direct DoD review of the program under the existing Nunn-McCurdy Act. In the 2008 Defense Budget, no money was deviated to furthering the ARH-70. A final attempt to offer the ARH-70 as an export product to help recover some cost fell to naught and the ARH-70 remained in limbo for the time being. At one point, it was expected that some 512 total systems could be purchased by the US military alone, the additional examples over the original agreed upon total being delivered for use by the Army National Guard to replace their aged AH-64 Apaches.
End of the Road
The ARH-70 program proved too much to be a viable option for the US Army, despite the mount reaching all required performance parameters. The Army Acquisition Executive Office for Aviation called for the DoD contract to be terminated in full. The US Department of Defense officially acknowledged the request and did not promote the multi-million dollar expenditure to the US Congress, effectively killing hope for Bell and their new little machine. By this time, a single ARH-70 example had nearly doubled in per-unit cost to an estimated $14.5 million USD. According to Bell, the contract was 53 percent complete at the time of its cancellation on October 16th, 2008, with some 1,500 test flight hours having been recorded.
Design of the ARH-70 followed suit with the OH-58 series family of light helicopters. The two-man crew was seated in a side-by-side arrangement well-forward in the fuselage. Each position featured redundant controls and large, transparent, bulging forward windshields offering excellent visibility. Each pilot maintained their own automobile-style doors, hinged at two points forward, for entry and exit into their respective cockpit seats. Optics and special mission equipment could be mounted externally under the "chin" portion of the fuselage. The passenger cabin was located directly behind the cockpit and accessed via side access doors. Weapon stub pylons emerged from the fuselage underside and could carry limited munitions for an offensive reach. Landing skids were affixed to either fuselage underside and supported at two fixed points. The single engine was fitted high atop the fuselage above and behind the crew cabin. Exhaust jettisoned upwards at the rear of the engine compartment. The engine drove a four-bladed main rotor and a two-bladed tail rotor. The empennage was raised at the rear of the crew cabin and engine compartment, capped by a tall vertical tail fin. Additional vertical fins were set along the sides of the tail system along horizontal planes. The tail rotor was set to face the portside of the aircraft.
Crew accommodations amounted to two pilots in the forward cockpit and up to six passengers in the main cabin.
Power for the ARH-70 was supplied from a single Honeywell HTS900-2 turboshaft engine delivering 970 shaft horsepower. This powerplant could supply the airframe a top speed of 161 miles per hour with a cruise speed of about 130 miles per hour. Her range was listed at 186 miles with a service ceiling equal to 20,000 feet. Empty weight registered at 2,598lbs with a maximum take-off weight equal to 5,000lbs.
As an armed reconnaissance helicopter and as in the OH-58D before it, the ARH-70 was intended to carry a rather modest arrangement of weaponry. Primary hitting power was to be supplied y a 1 x GAU-19 series 0.50 caliber Gatling gun fitted to an outboard pylon as well as Hydra 70 2.75-inch (70mm) rockets, also on an outboard pylon. Additional offense/defense could come from crew-served light weapons that might be fielded by the passengers from the cabin.
The Arapaho Name
Although referred to in a few official media reports under the designation of "Arapaho", this name was never officially assigned to the ARH-70 product.