The US Army’s new tiltrotor is in low-rate production, with Bell working to deliver the first example.
Rotorcraft manufacturer Bell has completed several key milestones in the assembly of the first MV-75 Cheyenne II tiltrotor for the US Army.
The company says it has completed assembly of the first nacelle structures for the lead MV-75, fitting those with a wing structure at its tiltrotor production centre in Amarillo, Texas. Bell has already fabricated multiple MV-75 wing sections at that site.
Separately, Bell has started testing the first gearboxes for the lead MV-75 test aircraft. A critical component of the tiltrotor’s drive system, the gearboxes are involved in electrical power generation, pumping hydraulic fluid and operating cooling blowers for the engines and nacelles.
Bell designed and produced the gearboxes at its Manufacturing Technology Center in Fort Worth, Texas, while the completed system is being evaluated at its MV-75 Drive System Test Lab in Grand Prairie, Texas.
At another facility in Arlington, Texas known as the Weapon System Integration Lab, Bell is maturing software for various MV-75 systems, including flight-control computers and large-area cockpit displays.
“The completion of the nacelles along with the start of gearbox testing and software integration mark significant milestones for the first MV-75 test aircraft and moves Bell and Team Cheyenne closer to completing the build and beginning flight tests,” the company says.
Bell’s design for the MV-75’s nacelles differs significantly from that of its in-service V-22 Osprey tiltrotor.
On the V-22, the entire nacelle assembly rotates, including the engine and proprotor, when the aircraft transitions between vertical and horizontal flight. For the MV-75, Bell redesigned that mechanism so the engine remains fixed and only the proprotor assembly pivots.
Bell says this will reduce mechanical complexity, simplifying maintenance and improving reliability. The company notes the nacelle accounts for 60% of all maintenance actions on the V-22. In 2021, Bell launched the V-22 Nacelle Improvement project to simplify wiring and enhance structural components in the critical assemblies.
Another major change is that the MV-75 will be built to accommodate an optional unmanned configuration, a capability Bell previously demonstrated with its V-280 Valor demonstrator, which served as the basis for the MV-75 design.
That capability could be used to “self-deploy” the new tiltrotor or for launching large volumes of munitions and uncrewed aerial systems, Bell’s MV-75 programme director Ryan Ehinger told FlightGlobal this year.
While the basic MV-75 configuration will be optimised for carrying troops to far-flung objectives, Bell is also working on special operations and medevac variants of the Cheyenne II. Unlike past aircraft development programmes, Ehinger says the base MV-75 was designed to easily incorporate speciality features (like an aerial refuelling probe) without requiring costly redesigns or modifications.
“We think getting to those variants quickly will be a lot easier because of the work we’re doing now in the digital space,” he notes. “For international variants as well, or other multi-mission applications, it’s a great platform for that.”
US Special Operations Command has said it plans to field an MV-75 variant to the army’s elite 160th Special Operations Aviation Regiment. Bell has separately displayed MV-75 models in US Marine Corps livery, although no such programme has yet been confirmed.
The company plans to assemble the Cheyenne II in Amarillo at the same facility that currently produces V-22s, which are nearing the end of their production run. Bell has completed MV-22 and CV-22 deliveries for the US Marine Corps and US Air Force, with work on CMV-22Bs for the US Navy continuing through 2027.
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