WASHINGTON — Four competitors, two clean sheet designs and $11 billion at stake. The Air Force's T-X trainer competition is heating up, and now that all four proposed aircraft have been made public, the field couldn't be any more varied.  

In the run up to the Air Force Association's Air, Space and Cyber conference, aviation enthusiasts got a glimpse of the two purpose-built trainers — a twin-tailed plane manufactured by a Boeing-Saab team and a compact design from Northrop Grumman, which is partnered with BAE Systems and L-3.

Those companies will be going up against at least two teams that are proposing modified versions of trainers operated by foreign air forces. And as exciting as the promise of shiny new aircraft can be, Northrop and Boeing will have to prove to the service that their T-X proposals are as affordable and low-risk as their rivals, analysts told Defense News.

"The challenge is, can the clean sheet designs catch up to T-50 and to a lesser extent, the T-100?" asked Rebecca Grant, president of IRIS research, referencing the Lockheed Martin and Raytheon offerings. "Can the clean sheet designs catch up and demonstrate what the off-the-shelf aircraft already have?"

Lockheed Martin and KAI are offering the T-50A, a version of the Korean company's T-50 in use by South Korea, Indonesia, Philippines and Iraq.  Raytheon, Leonardo and CAE have teamed up on the T-100, which is based on Leonardo's M-346 flown by Italy, Israel and Singapore.

The big question, according to Grant, is whether the Air Force ultimately will prioritize cost or performance in its final request for proposals due for release in December.

"I wouldn't count anyone out," she said. "We do have some quixotic requirements, and we do know cost and experience are going to be important."

In the latest draft RFP issued in July, the Air Force specified that entries with better maneuverability —specifically in high G and high angle of attack scenarios — would be incentivized in the proposal evaluation process. By exceeding the threshold requirements on both of those variables, companies could knock as much as $139 million from their offering's total evaluated price.

But that might not be enough to give a high-performance design by Boeing or Northrop the edge in a program worth about $11 billion, said Richard Aboulafia, an aerospace analyst with the Teal Group.

"Their competitors are going to get some of that too," he said. "In other words, they may be going after that performance angle, but it's far from a war winner."

After a showy rollout of the Boeing-Saab T-X in St. Louis, Boeing Phantom Works president Darryl Davis told reporters that the team's strategy is to build an airplane as close to the Air Force's threshold requirements as possible.

"We're not going to talk about details of what we can do above the threshold requirements," he said. Instead, company officials described an array of advanced manufacturing techniques that the team is employing to reduce cost and improve the efficiency of the production line, such as 3-D printed parts that can be made in hours and new adhesives that slash the time it takes to construct the canopy from six weeks to eight days.

The Boeing-Saab trainer is powered by a single GE 404 engine made by General Electric and has twin tails to aid maneuverability, an all-glass cockpit and stadium seating that makes it easier for an instructor to evaluate a student’s work. The aircraft’s twin-tailed appearance and "aggressive-looking surfaces" echo the fourth-generation styling of Boeing’s Super Hornet and F-15 more than it brings Saab's Gripen to mind, said Grant, who noted that the Boeing-Saab team may be downplaying its aircraft’s performance abilities for strategic purposes.

"I thought they might just have been a little cautious in not wanting to oversell their offering," she said. "It looks to me very much like it’s designed with performance in mind, but I think everyone feels at the end of the day that cost is a huge, huge discriminator in this competition, so I'm not too surprised to see the offerors underlining how cost effective their systems will be."

Boeing’s bombastic marketing approach couldn’t be more different than the other T-X competitor offering a clean-sheet design. Northrop Grumman has kept all information related to its proposal under lock and key, although details have begun to trickle out.

On Aug. 19, photos posted on Twitter revealed Northrop’s T-X prototype as it conducted high speed taxi tests in Mojave, Calif. A Northrop spokeswoman confirmed that the images showed the company’s design, but declined to elaborate.

Aviation Week later reported that the aircraft made its inaugural flight on Aug. 26, something the company refuses to confirm, but sources familiar with the program have hinted has happened.

Northrop Grumman’s T-X design appears to be hinged around maneuverability and high performance, and the company could be trying to wring as much money out of those incentives as possible, Aboulafia said.

Its prototype harks back to other Northrop-created aircraft like the T-38 trainer currently operated by the Air Force, with similar engine inlets and a long vertical tail. It also bears a resemblance to the "well designed, compact jets" built by Scaled Composites, a Northrop subsidiary that got its start producing experimental prototypes, he said.

Grant picked up on a similar strain of DNA.

"There’s a lot of Grumman in this design. It really reminds me of Grumman’s Navy cats," she said, referencing the string of fighter jets named after various wildcats — including the F-14 Tomcat made famous in Top Gun — built by Grumman Aerospace before it merged with Northrop.

Although much of the focus in recent weeks has been on the clean-sheet T-X offerings, Lockheed has fought to keep the T-50A as visible as possible. After the Boeing rollout, the Lockheed posted a video of the T-50 in flight on twitter with a quip: "Good on paper, better in the sky."

Lockheed Martin's T-50A trainer, its offering for the T-X competition, makes its first flight in June 2016 over South Korea.

Photo Credit: Lockheed Martin

Its first two T-50A trainers took to the skies this summer in Sacheon, South Korea. Then, in August, the company opened a new pilot training facility in Greenville, S.C., which will handle final assembly and flight operations. The first aircraft is slated to transfer to that facility in the fall, with the second plane arriving early in 2017, said Mike Griswold, Lockheed’s T-50A business development director.

"One of the things we want to show in South Carolina is verify that we can do sustainment of the aircraft, so we will be proving out our ground operations system," he said. The first ground-based training systems, which will complete construction this fall, will also be stationed there.

Griswold also stressed that the T-50A would be able to meet the performance incentives listed in the most recent draft RFP, indicating that the clean-sheets may not be able to beat existing options on performance alone.

"The basic T-50 and the T-50A variant meet all those objective performance levels for sustained G and angle of attack," he said. "We designed this aircraft originally as a T-38 replacement, knowing someday the Air Force would need to replace their T-38s. So we had our eye on that goal."

The Raytheon T-100 trainer can provide students with hands-on experience and mission simulations.

Photo Credit: James Way/Staff

Raytheon is touting not only the low risk of its T-100, but its entire training solution — a strategy that capitalizes on the contractor's experience in integration work. Leonardo will provide the Alenia Aermacchi’s M-346, with twin F124 engines made by Honeywell, while CAE will create the simulators and training coursewear.

To meet US requirements, Raytheon will made modifications to the M-346’s ejection seats and visual displays and insert an aerial refueling capability.

Beyond the 350-aircraft included in the Air Force’s program of record, Rick Yuse, estimates a further 350 aircraft sold in the international market, as well as sales of a light attack variant of the aircraft.

"We see this as a very large opportunity for us," he told Defense News in July. "This could be up to 1,500 aircraft."