Four Two Nine

The 429 is the manufacturer of the iconic Bell 47 and Iroquois series’ first all new civil helicopter in a generation and will play an important role in Bell’s future as it rationalises its product lines and streamlines its operations. From next year the 429 will be just one of four civil Bell models in production, alongside the 206L LongRanger and 407 light singles and 412 medium-lift twin, with production of the 206B3 JetRanger, 427 and 430 light twins winding up, all of which have sold in small numbers in recent years.

In contrast the 429 has enjoyed strong market acceptance since its launch in 2005, with today Bell holding orders and letters of intent for 330, a key component in the company’s current US$6.2 billion order backlog. The 429 first flew on February 27 2006 from Bell’s Mirabel, Quebec, Canada facility, where all its civil helicopters are manufactured. To date, with certification near, the five aircraft flight test fleet had accumulated over 1600 flying hours.

Bell developed the 429 in response to relatively lukewarm market acceptance of its 427 light twin, a twin PW207D powered evolution of the 407 which began entering service in 2000. Taking technologies from its MAPL – Modular Affordable Product Line – research program, Bell took a clean sheet approach to the light twin segment, unveiling the new model 429 in mockup form at the 2005 Heli-Expo. In all the 429 adopted some 13 technologies and features developed under the MAPL program

“That (MAPL) was really something that aimed at giving the customer the performance that they want, giving them that performance at low operating costs, and giving that performance at a price that is affordable,” Bell 429 program director Neil Marshal explained to Australian Aviation. “We adopted a very modular approach to build, we have long term plans to potentially generate some derivatives of this program and generate a whole new product line based upon it,” Marshall said. “So that modular build approach that we have is going to allow us to have a good manufacturing flow, thus reducing costs, which also reduces the ultimate sale cost to the customer.”

Central to the 429 is its large, box shaped flat floor cabin, which in an EMS configuration will allow the aircraft to carry two stretcher patients and attendants, or in a corporate configuration seat up to eight. The cabin features sliding and hinged doors on each side, and optional rear clamshell doors (as on the BK 117/EC 145). Four removable seat tracks can be used as hard points for equipment tie-downs (The floor has an aluminium base structure, providing flexibility for custom fitouts).

It has a “Flexible big open cabin, the ability to bolt down equipment on this floor, the capability and performance you get with it, the centre of gravity flexibility – we pretty much figure that you’re not going to need any ballast for most common kitted configurations typically used in the light twin market, “ said Marshall.

The 429 program chief also explained that the 429 had been designed to accommodate future developments and customisations typical for helicopters. “There’s a lot of inefficiencies that come with that post basic aircraft type installation work. Typically in the past you’d build the basic aircraft then you’d ask the STC suppliers to come along and try and string their air conditioning or bleed air around our stuff, and it’s very inefficient, adds cost to the customer, adds weight to the aircraft overall.

“So what we did up front was we for example routed air conditioning bleed air, all of our electrical kit wiring, and any kind of kits that we’d consider would normally go on this type of aircraft, auxiliary power supplies, avionics boxes that tend to get thrown in, we installed all that in the CATIA 3D design up front, so the real estate’s there. So then we came up with a more efficient way of routing things. So that’s enabled us to come up with a very weight effective solution, and that’s why you’ve ended up with this big cabin that’s still operating in Part 27 and still giving a very health payload to the customer.”

For the pilot the 429 is designed for single pilot IFR operations from the outset. It features a twin Rogerson Kratos LCD screen Integrated Instrument Display System, dual Garmin 430 or Garmin 430 and optional GNS530 nav/comm avionics, and dual digital autopilots with stability control augmentation.

Above the boxy cabin sits twin FADEC equipped Pratt & Whitney Canada PW207D turboshafts (as on the 427) but uprated to xxxx for the heavier 429. They power an all new composite four blade main rotor, plus Bell’s first four blade tail rotor for a civil helicopter. The chord of the main blades increases from inboard to outboard to about the three quarter span point, which Bell says is a very efficient and effective design, contributing greatly to the 429’s responsiveness. The blade tips on both the main and tail rotors are swept for noise reduction.

“That’s enabled us to come up with a very weight effective solution, and that’s why you’ve ended up with this big cabin that’s still operating in Part 27 and still giving a very healthy payload.”

Bell says in designing the 429 it established and quantified customer requirements for a light twin, from which it defined a set of key performance parameters against which the design was judged as its development progress. All those parameters have been met, Bell says, apart from falling 27kg short of the targeted 1950kg empty weight. As max takeoff weight is capped to 3175kg for FAR Part 27 certification standards, useful load has fallen slightly to 1198kg.

“It’s a huge cabin, and we had a target to hit, and we’re like a percentage point off it, which is pretty good given the size of the cabin,” said Marshall, who flagged Bell unveiling performance improvements for the 429 which would mean “ carrying that extra weight is not a big deal for most of the typical mission profiles”.

At Heli-Expo in late February Bell subsequently unveiled 429 performance improvements which had been validated by the nearly complete flight test program – a maximum speed is up 5kt to 147kt, range has increased to 364nm (674km) (up 14nm/26km) and endurance is now four hours (up from 3.8).

“You can pull spec sheets, you can go stand next to an EC 145 or an A109 and then stand next to this aircraft, and it is pretty clear what is going to be the market leader,” Marhsall noted. “And hopefully we’re that far ahead that it is going to take them quite some time to come out with something.”

One goal Bell hasn’t been able to quiet meet is its certification target, which was originally planned for late 2007, which has slid to May this year. In part delays have arisen as Bell has juggled resources to meet military program needs, while the most recent certification delays have been attributed to software certification, with certification testing of the helicopter’s airframe and systems otherwise complete.

Once certification is achieved however, customer deliveries against that 300 strong order book can begin. Marshall promises a “steady introduction into the market,” so that if there are “teething problems issues, you want to make sure that’s not affecting a hundred customers, maybe it is only affecting the first 25 customers.” In time Marshall expects the production rate to reach 100 aircraft a year early next decade.

A smooth running production line will also allow Bell to begin looking at 429 derivatives. The first planned development is a wheeled undercarriage variant , with the 429 designed from the beginning to accept wheeled gear. “The structure in a global sense has been designed to accept wheel gear loads,” said Marshall.

Beyond that, “Potentially we may push the 429 up into FAR Part 29, it’s capable of doing it, and if do that, it will have added payload, but we’ve got to look at the business case,” Marshall said. And, “We get a lot of customers saying ‘heck we love the 407, but if you could give us this cabin (the 429’s) with a single engine and good performance, boy wouldn’t that be great’.”

“It’s a good vision, we’ve just got to determine what our path is to get there.”

For now though the focus is firmly on certification and initial deliveries.

“I’m pretty proud, I stood next to the mockups when we first displayed them at Heli-Expo in 2005 and we’ve managed to come up with an aircraft that actually looks like the mockup and we met the promises that we placed against at,” said Marshall. “So I’m pretty proud to be part of the program.”