Bell Helicopter is making rapid progress on the flight-test programme for its developmental 525 Relentless, and has already flown the rotorcraft with its fly-by-wire controls fully engaged.
Larry Thimmesch, vice-president of the 525 programme, said that the initial 525 prototype has now accumulated more than 20 flight hours since its maiden sortie on 1 July 2015. In addition, it has amassed more than 40h of ground tests.
During flights, the GE Aviation CT7-powered helicopter has been taken to speeds of up to 162kt (300km/h), an altitude of 12,000ft and bank angles of 35°.
In addition, says Thimmesch, Bell’s test pilots have progressively introduced the fly-by-wire system – what it calls “Aug On” – with the helicopter flying at 120kt and 1,200ft.
“The pilots have even taken their hands off the controls a few times, and it can stabilise itself,” he says.
Initial autorotation trials have also been performed, with the Relentless successfully demonstrating that it can enter and recover from an autorotative state.
Overall, the flight tests are “going very well”, says Thimmesch, adding “we are progressing very quickly and moving through the tests”.
In fact, Thimmesch remains confident that Bell will meet and exceed its previously stated performance targets for the 525, particularly its never-exceed speed of 165kt and useful load, currently given as in excess of 3,720kg (8,200lb).
“We have some margin in useful load because we know there are usually changes in flight test,” he says. “We have already incrementally put out better and better performance and capability numbers as we have validated them. We are tracking to exceed our initial targets.”
A second flight-test article is structurally complete, with images released by Bell showing it already painted, bearing the registration N525B. Thimmesch anticipates the helicopter taking to the air before year-end.
This will be shortly followed by the third prototype, with two further helicopters – planned to be close to the eventual production standard – to arrive in 2016.
Bell intends to achieve certification for the 9.1t 525 by the end of the first quarter of 2017, with deliveries beginning shortly after.
Assembly of the first production helicopters are set to begin later this year. Bell is already working with the recipients of the early helicopters to define and certificate suitable mission kits.
It intends to install a certain level of mission equipment during the initial build, says Thimmesch, in order to reduce the amount of time required for later completion activities. He estimates this lag time can be cut to three months, down from a typical six to nine months on other heavy helicopters.
So far, Bell has taken in more than 60 letters of intent for the 525, including helicopters destined for oil and gas, search and rescue, firefighting and VIP transport missions.