A Better Build

The Bell 525 is progressing quickly from concept to functional aircraft. Bell Image
The Bell 525 is progressing quickly from concept to functional aircraft. Bell Image


Have you ever wondered how a helicopter design is really conceived, developed and brought to market? Well, it goes something like this:
1. The suits in the big offices decide they should build and sell a helicopter to fit a need they perceive exists.
2. The suits tell their engineers to design a helicopter to meet this marketing need.
3. The engineers, artists, marketing wordsmiths, and mock-up craftsman are cut loose to build hype and get initial orders with deposits.
4. Manufacturing is given the design and told to figure out how to build it.
5. Suppliers are asked to design and price the components.
6. Press releases abound with launch customer announcements, technical details, first flight reports, testing progress and excuses for missing initial certification dates.
7. After the design freeze, a big customer demands specialized coolers for hanging deer meat in the cabin.
8. Everything goes back to engineering to figure out how to cut a big hole under the engine deck to do the plumbing for the cooler.
9. The A model is finally delivered.
10. Work immediately begins on the B version to fix all the A model problems, and change the design to really meet the needs of the customers in that market group And, oh yeah, they also resolve the problem of the mechanic not being able to change a battery without having to pull an engine.
Okay, so Im having a little fun here. But, unfortunately, fun aside, the above scenario can often be much closer to truth than fiction. Sometimes the development process goes more right than wrong, and sometimes its the reverse.
Weve all seen the quantum leap in technology over the past decade when it comes to the aircraft we fly especially in the area of avionics and training simulation. What may not be as obvious is how much the advances in technology are changing not only what is designed for new helicopters, but how they are designed. Bell Helicopters 525 Relentless is a perfect example of both. Announced with much fanfare (some things never change) at Heli-Expo 2012, the 525 represents a significant departure for Bell in many of the companys design and marketing practices, as well as the employment of some of the most advanced systems ever incorporated into a commercial helicopter.
A Different Approach
So, keeping in mind the aforementioned traditional approach to designing a new helicopter, lets follow how Bell revised the process for the 525, and look at the end product the company is expecting to obtain.
First, the idea was put out there for an all-new, clean sheet, medium-class helicopter that could do the work of a heavy-class ship, with the goal of offering more passenger capacity, more speed, and more range to service the increasingly deep and distant offshore oil-and-gas market. Not surprisingly, to capture more market share, other key disciplines such as corporate and VIP , helicopter emergency medical services, firefighting, and search and rescue were also targeted. Okay, no revelation yet.
In December 2010, Bell began with surveys of its customers, picking their brains for input on where they saw the market in the next five to 20 years, and to determine the right sizing for future markets and technology. A customer advisory panel (CAP) was also assembled, representing a full 40 percent of the oil and gas market, and 11 percent of the total represented market. Again, no real revelation, customer blue teams and the like have been used before.
What is different for Bell, however, is that working in conjunction with the CAP is the integrated production team (IPT ). Members of this comprehensive team work together continuously to cover design and development of all aspects of the helicopter. But more importantly, besides design engineers, the team also includes representatives from marketing, manufacturing, the supply chain and maintenance.
The engineers, along with other members of the IPT , traveled to the CAP operators to see first-hand through multi-day visits how the operators use their helicopters, and what they need in a new machine and its operating systems. As a result, 82 major kits are under design and supplemental type certificate development and will run concurrently with the certification of the base ship. Batches of kits will be released in the order of market capture, with oil and gas being first since it represents 53 percent of the market for this class of helicopter.
Concurrent design with defined kits also means that the base aircraft will be ready to accept these kits as intended, rather than in patchwork as an afterthought. No more cutting holes for hooks, winches and various camera mounts. This also means that a 525 configured for, say, helicopter emergency medical services can ultimately be sold and reconfigured for another discipline with little hassle.
Additionally, significant consideration is being given to have a completed helicopter that is much more field ready. One example of this can be seen in the fact that previously many coastal operators received a new ship and immediately imposed three months of down time to strip the helicopter down for application of corrosion inhibitors. The 525 will be produced as corrosion averse to begin with, thus negating the after-sale step.
Part of the design process is to create a helicopter that is more on condition for component overhaul and replacement. Mechanics were also involved from the outset, with the task of advising on methods to streamline field maintenance and cut the need for specialized tools to a minimum. Also, major suppliers were brought on board early in the development process, driving detail designs in support of the program plan. This means the suppliers told Bell from the outset how the component will be built, providing the engineers with critical information on the best way to incorporate each component for manufacture and maintenance from the start.
Of course, enhancing the new approach for Bell is the advancement of computer-aided design (CAD). The detail and accuracy of CAD is overshadowed only by the ability to rapidly transmit original or modified designs to critical IPT members for review and response. Not only that, but a regular event has been a design change, or just an idea, being transmitted to the simulation lab (more on this shortly) and by the time the key individuals get to the lab, the simulation gurus have already incorporated the changes into the simulator for evaluation.
Finally, the CAP will remain on board for 12 to 18 months after deliveries begin to provide input on operations and maintenance. In sum: the conga line method of helicopter design dies with the 525.
By The Numbers
So, what has all this resulted in so far? I recently spent the day at Bell headquarters in Fort Worth, Texas, to receive a full progress briefing on the 525 Relentless; examine the full airframe, cabin and cockpit mock-up; and fly the simulator to find out. 
The preliminary design phase was completed on June 26, 2012, which froze the basic configuration and interfaces. One thing that struck me immediately was how sleek this aircraft looks. Although targeted for mostly utility markets, the 525 will certainly satisfy the most demanding of corporate egos.
The 525 Relentless will be in the 18,000-poundgross- weight class, with construction being a roughly 50/50 combination of metal and composites. General Electric CT 7-2F1 engines will be driving a five-bladed main rotor system.
Bell is stating cruise speeds in the 140-plus-knot realm, and cruise distances of over 400 nautical miles. One of the mantras I heard repeatedly was that Bell intends to under promise and over deliver, meaning that the company is confident the 525 will outshine the preliminary performance specs.
The standard configuration will be seating for 16 passengers, plus two pilots. However, one of the design objectives of the 525 is for it to be certified for single-pilot instrument flight rules. Access to the cabin will be through two doors on each side. The forward door provides access for the pilots, as well as the first row of passenger seating. 
One big design departure is that the pilots do not have their own doors. There are two large (emergency-exit capable) windows instead in their place. After considerable evaluation by the CAP and IPT , it was determined that with the benefits of reduced weight, increased visibility, and J-track pilot seats that slide and turn for easy entry/exit, pilot station doors were not necessary. Plus, the seats will have a memory function so the pilots dont have to adjust them after each exit/re-entry.
The main cabin exuded the feeling of rugged comfort. Nothing encroaches into the cabin since all critical components are above the ceiling. This will also facilitate the smoothest ride of any Bell aircraft, since 95 percent of any vibration source will be captured above the cabin. The capture will be accomplished through a multi-faceted vibration isolation system designed for vibration attenuation at its source.
Also, no passenger is more than one seat away from an exit. The seat pans are 20 inches wide and each row fits four across. There are overhead air vents for each passenger, plus an additional floor air supply. Bell is keeping the floor simple, with no seat tracks. This makes it easy to clean, and it supports modularity. I can only imagine how cavernous this cabin would look empty.
The front office is clean and modern, sporting the ARC (awareness reactive control) Horizon fully integrated flight deck. This ARC flight deck is a combination of ergonomics, cockpit visibility, avionics and an advanced fly-by-wire (FBW ) flight control system.
Yes, fly-by-wire. The triple-redundant system has no mechanical back-ups. The system joins only at the flight controls and the rotor head/tail rotor actuators. Between those two points are three completely independent wire bundles serving three different control computers. Certification will include passing the axe test: severing complete systems to prove the back-up redundancy.
Just a few of the benefits of the FBW system include: side-stick controls providing closer access to displays; tactile limit queuing, in which the stick alerts the pilot when limits are being approached; basic ship automatic approach to hover, auto-hover capability and automated departure profiles; full-time, high integrity gust alleviation and stability augmentation; automatic transition into autorotative descent, to provide the flight crew with more time to deal with emergency management in critical situations; and the FBW capability to automatically and quickly respond to a one engine- inoperative condition.
The 525 is the first helicopter to incorporate the Garmin G5000H touch-screen avionics suite, giving the ARC Horizon flight deck 3-D audio, TC AS-II (traffic alert and collision avoidance system), ADS -B (Automatic Dependent Surveillance-Broadcast) In/Out, HT AWS (helicopter terrain awareness and warning system), synthetic vision, enhanced vision, and seamless integration of multi-directional vehicle cameras into the displays to provide exceptional viewing from pilot/co-pilot seats. Lastly, intuitive, user-friendly color icons on pedestal-mounted, IR , data-entry screens make flight-management-system programming a welcome experience. Id swear that if you can operate a Garmin 696 or 796, or even the Garmin iPad app, you can program the G5000H.
Testing It Out
So, after all the briefing and reviewing, my time came to fly the 525. Well, sort of. Actually, it meant flying the non-motion simulator in the sim lab. 
Prior to this flight, any simulator I had flown was based on having some sound experience in the real airframe, which the box simulated. But for the 525, the airframe and its systems exist only in virtual and mock-up form. 
However, the incredible advancement in simulator technology to closely replicate the characteristics of a certified helicopter yields a major advantage in reversing this process to where design parameters, and wind tunnel testing, etc., can be applied to the sim to sample how the eventual aircraft will fly. Indeed, if the sim really represents how the 525 will fly, then its pilots are in for a treat.
And, by the way, this particular simulator rivaled many of todays non-motion sims in terms of clarity, field of view and realism of the flight scenario. (Also on a parallel path with the 525 will be the development of a full-motion flight simulator and all of the United States Federal Aviation Administration approvals that go along with it. This way, when the 525 is certified and ready for delivery, certified training will be ready, as well.) 
The primary purpose of my flight was to evaluate the fit, feel and handling of the 525, and its FBW controls and related benefits. 
Once inside, I felt like I was sitting at the command station of a starship. No more between-the-legs cyclic stick and a big, long armed collective on the left, I would now be using two side sticks for flight controls. Having experienced the transition from standard controls to side sticks in fixed-wing aircraft and how easy that was I wasnt expecting much difficulty in adapting to the 525.And I was right. I became pretty comfortable, pretty quickly.

Both the cyclic and collective sticks have very little throw. Its now all in the wrist. In fact, its usually in the thumbs. On the cyclic, there is a coolie hat for all typical left/right, fore/aft stick movements. Similarly, on the collective, up or down on the coolie hat yields up and down collective. Left and right beeps tail rotor control. I rarely used my feet throughout the entire flight period.
With FBW , and the way the 525 was set up, some typical moves yielded non-standard results. A primary example was: in a conventional helicopter, if youre moving along in cruise and put in some aft cyclic, youll get a cyclic climb and gain in altitude. Doing so in the 525, the computers are programmed to actually reduce power, add the correct amount of pedal, and slow down while maintaining altitude all from one simple aft cyclic move.
Had I desired to climb instead, all I would have needed to do was add a little collective. At first, being old-school, I wasnt sure I liked this control response difference. But by the end of my pretty comprehensive flight period, I really could see the benefits. And here again, the advantage of the new design process incorporating the CAP and IPT , is that this is not set in stone yet. And with the aircrafts FBW and computer basis, design details are easy to change.
My first landing attempt was to an oil rig. I was particularly cautious since I was dealing with some new control concepts. The 525 responded nicely to my traditional style of flying. But it flew better when I left it alone literally. I beeped all three axis controls to the pad, feet on the floor, and then when it was where I wanted it over the pad, I took my hands off everything and it just stuck itself into position. Some mini-beeps on the collective to touch down was all I needed to do.
The same applied for my vertical takeoff. The 525 maintained relative position over the center of the pad by itself during the vertical climb until I commanded it to move forward. My next test came when I positioned over the shoreline to do a hover turn around a tower on the beach. In an out-of-ground-effect hover, I placed the tower off of my right side, with the helicopter parallel to the shoreline. In fact, I used a seam in the simulator screens as a target sight. Thirty knots of wind directly off of the water was then introduced. As this occurred, I could see the 525 roll into the wind to maintain position.
As I continued around the tower, the 525 automatically changed its wind correction attitude to maintain whatever position I wanted over the ground. Impressive indeed. Equally impressive was the visibility. I never saw the nose of the helicopter, and all the open area where a door would normally be allowed for exceptional views. Even cross-cabin visibility was good due to the low-profile panel. Its clear this helicopter is designed for heads-out flying.
Additional flying included an approach to a confined mountainside field. In this case, I just flew the 525 like I wanted to. I didnt worry about whether I was too heavy or light on the controls, or try to think about how the FBW computers were set up to react to inputs. Even during the sideways approach, everything felt great.
At low-altitude cruise flight, I entered a pretty rapid quick stop followed by an approach to a cross road. If this simulator is indeed accurate to how the 525 will fly, then it doesnt feel at all like a heavy-disguised-as-a medium helicopter. In fact, it may be too easy to fly.
The Path to Certification
And speaking of flying, in the second quarter of 2013 Bells Xworx facility will begin producing five prototype aircraft to be utilized for flight-testing. Additionally, computational fluid dynamics, wind-tunnel testing and the sim lab along with extensive FBW experience obtained from the Bell/Agusta BA609 (now AgustaWestland AW609) project will all factor into the path to certification.
However, regardless of how high-tech the process is, it still has its risks and trials. A Bell 214 that was being used to test some of the components and systems of the 525 crashed this past summer. The cause is still being investigated. However, this was not expected to impact the 525s developmental progress.
First flight is targeted for some time in 2014 and certification will be as soon as possible after that. One note: certification will be an ongoing process during the development of the 525, meaning that as components are ready they will be certified parallel to aircraft testing in the hopes of speeding up the overall process.
So, how many orders does Bell have for the 525? None… And, that is another departure from the norm.
Bell is going to show you, not tell you, and If we build it, they will come were two other mantras echoed throughout my visit. Bottom line, Bell is not taking orders on the 525 until its in a sales-ready status meaning not until the company has designed and built it, and proven what it can do.
This decision initially seemed like a gutsy move. But when I thought about it, with the CAP representing such a huge share of the 525s potential markets, the IPT process Bell is taking with this clean-sheet helicopter, and what Ive experienced so far, maybe its not that much of a risk at all.
Guy R. Maher is a 16,000-hour dual-rated pilot and flight instructor for helicopter, airplane and instrument ratings. He is an EMS pilot flying an IFR Eurocopter EC135 in North Carolina. In addition tobeing a FAASTeam representative, he is frequently called upon to provide consultation on aircraft sales, operational, and safety issues, and to provide testimony for legal proceedings. He can be contacted at [email protected]

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