Bell Helicopter is building a new demonstrator aircraft to prove the
OH-58D Kiowa Warrior can remain a viable, long-term option even as the
US Army seeks a huge boost in performance.
Inside Bell’s Xworx advanced programmes group, a re-acquired 206B1
JetRanger is being heavily modified. First, the aircraft will be
converted into the OH-58D design on which the 206B is based.
Then Bell’s staff will install a new engine with 50% more power than
the 650shp Rolls-Royce Model 250 CR30. Honeywell has provided a 975shp
HTS900-2, the engine originally built to power the now-cancelled Bell
ARH-70 armed reconnaissance helicopter.
With the extra power, Bell’s Xworx team hopes to show the army that the
OH-58D can be upgraded to meet the army’s potential demand for an
aircraft that can hover out of ground effect at 6,000ft on a 35ºC
Michael Miller, executive director of Bell’s military aircraft
operations, believes the engine upgrade will allow the Kiowa Warrior to
meet the army’s target for hover at altitude. However, integrating a
more powerful engine may not help the helicopter achieve the army’s
possible endurance goal of 2h45min.
“I don’t think it will hit that” performance target, Miller says.
But Bell wants to prove that the OH-58D has the growth capacity to
approach the army’s emerging needs for a more powerful scout helicopter.
Integrating the HTS900-2 engine requires other major changes for the
OH-58D, Miller says. For the demonstrator, Xworx is integrating the
transmission from the 407 and the tail rotor from the 427 helicopters.
The engine cowling for the HTS900-2 also is significantly larger.
Miller declined to provide a timeline for first flight of the
demonstrator. A tour of the aircraft on the shop floor at Xworx showed
that the cabin structure is nearly complete, but the engine, power
system and cockpit systems have not yet been integrated.
The full-scale demonstrator – a first for Bell in several years – will
join several candidates for a possible future army contract.
The army is still considering options for an armed aerial scout (AAS)
helicopter that may replace the OH-58D. An analysis of alternatives is
scheduled to be completed by April 2011.
The Kiowa Warrior remains in heavy demand in operations in Afghanistan
and Iraq, but the type’s limits are showing. The OH-58D was introduced
in the early 1980s as an interim scout helicopter, but two attempts to
replace it with the RAH-66 Comanche and ARH-70 Arapaho have failed.