The latest in model-based systems engineering, an agile mindset and help from Sweden? TIM ROBINSON reports from St Louis on Boeing’s T-X advanced trainer and asks whether Boeing has broken the mould for military aircraft development.
In September 2018 the USAF selected the Boeing T-X for its Advanced Pilot Training System (T-X) programme – designed to replace its aging T-38 Talon advanced trainers – which initially entered service over 50 years ago. This giant win sees Boeing provide 351 aircraft for the USAF (along with simulators and support) for a cost of $9.2bn – and could eventually rise to a total of 475 airframes.
The Boeing T-X (which also saw Sweden’s Saab as a partner) was remarkable in not only was it a clean sheet design that triumphed against existing ‘lower risk’ competitors – already in service - such as the Lockheed Martin/KAI T-50 and Leonardo/Raytheon T-100(M346) but that also it came in $10bn cheaper than the $19.2bn the USAF had forecast. Post-contract award, some observers thus wondered - had Boeing aggressively ‘low-balled’ its bid by 50% in order to win T-X at any cost? Or had it managed somehow to reverse the seemingly inevitable trend of ever-increasing cost of military aircraft?
Boeing/Saab T-X design secrets
Winner of the T-X advanced trainer contest for the USAF.
At a media briefing in Boeing St Louis, the home of T-X as well as F/A-18 and F-15, Paul Niewald, Senior Director & Chief Engineer, T-X, gave an insight into the design and development process of this supersonic trainer developed in only three years – crediting the latest in ‘model-based systems engineering’ and an ‘agile mindset’ as to being behind the programme’s success in winning the contract.
Currently lacking an official designation and name, Boeing’s T-X is an advanced jet trainer powered by single GE404 engine. It features twin tails, FBW and a tandem co*ckpit with a side-opening canopy. In configuration it looks rather like a single-engine Hornet, with the front section of a Gripen (ironically it is Saab that provides the rear fuselage from behind the co*ckpit). It first flew in December 2016.
Says Niewald: “The T-X programme and T-X aircraft features a lot of disruptive technology both in design as well as in the manufacturing aspects. We were competing against proven in-production aircraft, so we had to do things differently if we were going to compete and have an aircraft that was viable for that campaign.”
He explained: “We had to rapidly get out there and get a configuration. We used the latest in model-based engineering to help define what that configuration was and set that configuration. We used computational fluid dynamics (CFD) to go ahead and get the aero and loads that we would need for detailed design. This allowed us to go much faster, with much more understanding of the configuration earlier than if we had to go and design wind-tunnel models, put those into a wind-tunnel test and analyse those.”
Niewald also credits an ‘agile mindset’ in the small ‘Skunk Works’-like team and its suppliers that meant that everybody was on the same page and working to the same ‘cadence’. This agile mindset saw a block plan for hardware and software integration, with software being updated every eight weeks. This saw a 50% reduction in software hours needed. Quicker avionics updates also allowed the simulators to stay concurrent with the aircraft – a feature that will be extended into service – removing the negative training where simulators ‘lag’ avionics and features in the real aircraft.
Fifteen flights without a single snag
Build quality and reliability was unprecedented for a clean-sheet prototype. (Boeing)
The results of harnessing the latest in high-fidelity model-based systems engineering have been impressive. The 3D digital modelling of T-X, says Niewald, with one master tool, “allowed us to have a 75% increase in engineering first time quality.” He added: “This also enabled us with self-locating parts. We were able to splice the fuselage in under 30 minutes where traditionallyit would take us 24 hours.” The canopy was another area where advanced manufacturing was coupled with the model-based design, with an injection sealant gluing the transparency to the frames replacing 600 traditional fasteners. Says Niewald: “We had planned for six weeks in the schedule to be able to assemble the canopy. It took us eight days. Techniques like this allowed us to reduce touch labour on the aircraft by 80%.”
Thanks to the increased fidelity of today’s model-based engineering, this rapid design and assembly did not lead to any lowering in quality. “The rework was very small - 0.3%”. Indeed, Niewald says that the two T-X demonstrators should not be classed as traditional ‘prototypes’: “We didn't build just one aeroplane - we built two jets that are not prototypes. They are production jets. We built them with the same processes that we are going to build hundreds more and we've validated those processes with these two. In my mind these are the most identical jets we've ever built.”
But perhaps the most impressive statistic from Niewald is that, ‘prototype’ or not, it took a full 15 flights before a T-X test pilot recorded the first ‘squawk’ or defect on an aircraft. Indeed, during the 71-sortie flight test campaign, the second flight was made on the second day and at one point the aircraft were flying up to four times a day.
As well as the manufacturing and tooling, care has also been taken to make the T-X as easy to maintain as possible from the ground crew’s point of view. For example, the aircraft features quick-access panels at head height, a high wing, and interchangeable left and right stabilators. A team of four technicians, meanwhile, can change the engine in hours. Finally, a side-opening canopy means that ejection seats can be removed individually, without having to remove the canopy itself.
Swedish partners
Has T-X incorporated lessons from Saab's Gripen? (Saab)
Boeing’s model-based engineering and ‘agile mindset’ has also benefited from outside help from Sweden’s Saab – well known for developing a highly affordable, yet capable fourth generation fighter in the Gripen. Having signed a partnership in 2013 with Boeing as prime contractor, Saab was given the rear fuselage to develop and assemble. In May 2019, Saab announced it is to invest $37m in a new factory in Lafayette, Indiana, to produce its share of the T-X.
Notably, Saab’s Gripen shares much of the focus on affordable, simple maintenance that informs the design of T-X – a holdover from the Cold War days where Swedish conscripts with minimal training were expected to be able to turn-around jet fighters in austere conditions. How much of the Gripen mentality has leaked over to Boeing on T-X is difficult to judge but without mentioning Saab directly, Niewald says: “From a partnership standpoint it was very refreshing to have teammates that thought and had the same sort of goals that we did as to how we wanted to innovate going forward on T-X.”
A 21st century trainer co*ckpit
T-X co*ckpit features a large screen display, digital up-front controller and standby instruments. (Boeing)
One aspect of T-X that Boeing has kept close to its chest in the development of T-X for the USAF, has been the co*ckpit layout. This features a large touchscreen screen display, digital up-front controller (UFC) as well as HOTAS and low-profile HUD as sidestick. In particular, the large single widescreen display echoes the F-35 display as well as the single display for the Block III F/A-18 Hornet, F-15QA/EX and Saab’s Gripen E.
But the large screen size is only part of this. As part of its ‘agile mindset’ Boeing has taken the avionics development of T-X in-house to create a co*ckpit display aimed at the smart-phone savvy ‘digital native’ pilots of tomorrow. The interface, for example, features iPhone/Garmin G1000-like ‘app’ icons for different functions (checklist, fuel etc), making for an extremely intuitive and user-friendly co*ckpit for student pilots, who can concentrate on flying the aircraft and the mission. The avionics suite includes synthetic radar and weapons as well as datalinks to link with other T-Xs, and being future-proofed for LVC (live-virtual constructive) training.
Boeing is providing some 46 associated simulators and training devices for T-X. These feature Boeing’s Constant Visual Resolution System (CVRS) graphics technology, which features pin-sharp graphics wherever you look around the dome – whatever the field of view. (Other visual systems, say Boeing, can cause ‘negative training’ when pilots work out the ‘best’ place to spot bandits on the screen – effectively cheating.)
Powered by a GE F404 (the same as in a Gripen C/D), the T-X has no shortage of power. T-X Chief Test Pilot Steve ‘Bull’ Schmidt says of the aircraft: “It flies like a fighter - extremely crisp roll, with no AoA restrictions. Fun to fly and really zips around the sky." Excess power, LERX and twin tails also mean it can provide the perfect lead-in to the higher performance US front-line fighterssuch as the F-22, F-35 and F/A-18E. Schmidt will not name the T-X's maximum angle-of-attack but did admit that it is beyond the 25deg requirement from the USAF.
In short, while the T-X may replace the T-38 Talon, the USAF also see the introduction of its first advanced trainer in over 50 years as an opportunity to streamline, accelerate and get aircrew to the front line faster, and at a higher level of readiness – saving money by allowing operational squadrons to focus on high-end training and tactics.
T-X on the international market?
Aiming now for foreign sales?
Under an initial $813m contract, Boeing/Saab is to deliver the first five EMD T-X aircraft to the USAF at Randolph AFB, Texas, in 2023, with initial operating capability set for 2024 and full operational capability is planned for 2034. However, while Boeing has focused so far on winning the big USAF prize, it is now talking up potential international export orders and T-X growth into new capabilities, such as aggressor, ‘companion’ trainers or light fighter/attack. Indeed, as part of the design process, potential for future growth such as adding weapons or sensors has been built in from the start – although the company is coy about the specific number and carrying capacity of hardpoints. Boeing’s Ted Torgerson, T-X Senior Director, believes that T-X enters a worldwide market of 2,600 advanced trainers/light attack.
This is an extremely crowded market – with existing jet aircraft (Hawk, M346, T-50, L159NG) as well as turboprops such as the Super Tucano dominating light attack. Torgerson, though, is bullish about the competition, saying: “They can’t touch our cost.”
Revolutionary or evolutionary?
Clean-sheet military aircraft designs are rare these days. (Boeing)
So, is Boeing’s approach to T-X then a revolution in military aircraft design and development – or simply an evolution of older tools and techniques? Computer aided design (CAD) for instance, dates back to the Boeing 777 – and its first ‘digital twin’ created in 1989 some three decades ago. Meanwhile, another St Louis product, the F/A-18E Super Hornet in the early 1990s, also saw the introduction of single assembly fixtures in place of sub assembly jigs and reduction in parts count from the earlier F/A-18 Hornet.
Dr Michael Pryce, Academic Lead for Policy Engagement - Cranfield Defence & Security and member of the MoD Independent Scientific & Technical Advice (ISTA) register,notes that “T-X is small, simple and largely made of traditional materials, without stealth coatings etc. All that helps make it predictable and maybe sound a bit boring.” Pryce also points out that McDonnell Douglas’ British partnerships with the Hawk (T-45) and Harrier (AV-8B) may also lie in the DNA of T-X. “Of course, Kingston and St Louis are linked by Harrier and Hawk. The canopy idea mentioned is the same as Hawk for example, as is the ground crew of four. SAAB also designed the Gripen with these features (conscripts can only do simple tasks). So 70's and 80's ideas from abroad, along with 90's CAD and Boeing's 00's shop floor experience = model-based systems engineering?”
While the ideas may be not new, Pryce notes: “The real area of interest is in the reduced maintenance and operating costs Boeing promise” adding; “If this low maintenance approach works it could be a very valuable lesson for [UK’s] Team Tempest, as does the fact that Saab seem very happy to work in novel ways with partners, not simply old fashioned 'work share'. Less money for maintenance means you can buy more aircraft and competent partners mean you can develop them more rapidly.”
The T-X’s approach to rapid design and development, along with affordable support, could have lessons for more complex and sophisticated aerospace projects – not just in Boeing – but around the globe as companies and nations aim to break the mould on the spiralling cost of military aircraft.
Tim Robinson
28 May 2019
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