An Iron Bird that Flies
Whether it’s range, speed, comfort or capabilities, Gulfstream has always set the standard by which all other business aircraft are measured. So when Gulfstream introduced the ultrahigh-speed, ultralong-range G650 in 2008, there was a certain amount of confidence that the aircraft, designed from a clean sheet of paper, would exceed the expectations that Gulfstream set for customers. That confidence comes in part from the Integration Test Facility (ITF) and a full-scale systems testing platform affectionately called the Iron Bird.
LEVERAGING THE ITF
To deliver on all the G650’s performance promises including a maximum range of 7,000 nautical miles/12,964 kilometers and top speed of Mach 0.925, Gulfstream’s engineers would have to introduce some truly cutting-edge technologies. Many, like fly-by-wire flight controls, would be new to business aviation and would undergo thousands of hours of engineering and integrated testing long before the aircraft ever began to take shape.
“The ITFs were introduced back in 1993 with the GV,” explains Bob Farrell, manager, Systems Test. “As the systems on the aircraft have become more integrated and sophisticated, the ITF’s capabilities have increased in value to our engineering teams.”
As a third-generation ITF, the G650’s system is the latest in a line of successful platforms. It features a cockpit configured and equipped just like any G650 in the field and a cabin section with a fully equipped galley, lavatory and Gulfstream Cabin Management System. Back in the “tail” you’ll find SATCOM boxes, Emergency Locating Transmitters, battery, and even the small lights that shine on the tail to show off the customer’s logo. According to Farrell, if it’s in a production G650, you’ll find it in the ITF.
From layout to installed equipment, keeping the ITFs as close to the actual aircraft as possible was critical.
“The ITF was built using as much production hardware as we could so the engineers could replicate aircraft conditions and component operations as closely as possible,” Farrell says. “From the main cabin door forward the cockpit is just like a G650. The floor structure is production and the nose, complete with Gulfstream demonstrator livery, was even painted in the same booth as a customer’s G650.”
While the cockpit is to scale, due to space limitations in the building the cabin length isn’t full size, but the engineers that built the ITF used all the same wiring harnesses, plugs, connectors and components found on any production G650.
“Over 80 percent of the equipment in the ITF is flight worthy at any time and could be placed on any aircraft in service,” according to Farrell. “We need to use the same LRUs [line replacement units] that are found in the aircraft to make our tests and evaluations as realistic as possible.”
The goal of the G650 ITF, and all the ITF units, is to give engineers an “as close to the real aircraft” tool to test everything from how the digital autopilot integrates with the Triplex Flight Management System to ensuring that an iPhone or iPad can be used to control the electric window shades.
If the engineers want to test the fax machine, they actually send a fax to the ITF via the roof-mounted satellite antenna. “We don’t cut any corners with our tests,” Farrell says.
As a third-generation ITF, the G650's system is the latest in a line of successful platforms.
THE AMAZING IRON BIRD
While the ITF gives Gulfstream engineers the perfect tool for testing and evaluating the hundreds of individual components and systems found on the G650, they still needed a solution to the challenge of developing a new fly-by-wire control system for the biggest, fastest Gulfstream ever.
“The G650 is our first aircraft with all of the controls electrically signaled,” states Joseph Cudnik, group head II, Advanced Design Research Labs. “We replaced the typical push/pull mechanical linkage with fly-by-wire technology. It took a lot of time to develop our unique distributed architecture and smart actuation control systems. Nothing this sophisticated had ever been done on this size and category of aircraft before.”
Along with fly-by-wire, the G650 also features brake-by-wire.
“Obviously the only way to develop the system at the lowest risk and cost was to build an actual size model of the aircraft to help design, test and evaluate all the various components,” Cudnik says. “The result is the Iron Bird. It’s a full-scale 3-D wire frame representation of the G650.”
Because the Iron Bird can do both static and dynamic testing, it allowed the flight control engineers to experiment with a variety of fly-by-wire configurations.
“We have aero-loading capabilities on all the flight controls so we can ‘fly’ the aircraft at any speed and in any configuration we want,” Cudnik explains. “You can pick any point in a 3-D flight envelope and add all the control loading associated with that point to the controls to fully understand how the aircraft will perform. We logged over 9,000 hours of testing and evaluation of the various systems before the first G650 test aircraft flew.”
BEST OF BOTH WORLDS
Having either the ITF or Iron Bird at one’s disposal would make any engineer’s day, but at Gulfstream the capability to use both of these advanced development and testing facilities has proven to be invaluable.
“We have a lot of varying capabilities with the two systems,” Farrell states. “The ITF has one set of capabilities and the Iron Bird has others. Put the two together and it equals total G650 systems integration testing and validation capabilities for Gulfstream.”
While the ITF/Iron Bird combination has enabled Gulfstream engineers to develop, install, test and prove many new systems in the most timely and cost-effective way, receiving the G650’s Federal Aviation Administration type certificate doesn’t mean the units will be retiring.
“Our goal has always been to continually improve the value and reliability of all our aircraft to our customers,” says Cudnik. “They want the confidence that comes with knowing we have tested and will continue testing everything to the greatest degree possible.
“Like with all of our ITF ‘fleet’ aircraft, we plan to upgrade the G650 ITF and Iron Bird hardware and software to reflect the equipment that our customers are using,” added Cudnik. “By doing that we can spot trends and develop solutions and upgrades to help our customers get the most value, safety and reliability from their Gulfstream for years to come.”
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