The U.S. Army has selected Textron (NYSE:TXT) and Lockheed Martin (NYSE:LMT) to battle to build its new Future Long-Range Assault Aircraft (FLRAA), with the prize a potential $40 billion-plus contract to replace the UH-60 Black Hawk helicopter.

The Army has awarded Lockheed's Sikorsky unit, which is working with Boeing (NYSE:BA), $97 million to refine its Defiant design, while Textron's Bell division won $84 million to put to work on its V-280 Valor. The two aircraft will compete in a demonstration phase expected to run two years, with the winner expected to be selected during the government's fiscal 2022.

The stakes are huge. The U.S. Army might not replace all of the more than 2,100 Black Hawks currently in service doing mostly troop transport, air assault, and medical transit, but the service is expected to purchase at least 700 of the winning design at an estimated sticker price of more than $50 million apiece. Add in development costs and the program will run at least $40 billion.

The award isn't a surprise, as the Pentagon telegraphed in its February budget request that the FLRAA program continues to be a top priority. But it is a huge vote of credibility for two new, and relatively untested, designs, and could provide a much-needed spark to Textron. Here's a look at how the finalists stack up.

The V-280 is already turning heads

Bell's V-280 and the Defiant are graduates of the Army's Joint Multi-Role Technology Demonstrator program, an effort by the Pentagon to modernize helicopter design and introduce new technologies. The V-280 has been airborne since 2017 and has logged significant flight hours.

The tilt-wing design is intended to give the V-280 higher speeds and better range while still allowing it to perform helicopter maneuvers including landing and taking off without a runway and hovering in place. The V-280 can hit airplane-like speeds, with the company touting a cruising speed of 280 knots (hence the name) and a top speed approaching 300 knots.

The V-280 shown dropping troops off in a battle zone.

Artist rendering of Textron's V-280 Valor. Image source: Textron.

The V-280 was airborne well before the Defiant and has had a chance to show its strengths to the Army. The V-280 in December flew autonomously during a demonstration before an audience that included Army Secretary Ryan D. McCarthy and Congresswoman Kay Granger of Texas. Autonomous capabilities are not expected to be a requirement in any upcoming helicopter competitions, but it is an area that the Pentagon is interested in pursuing.

The issue with the V-280 is what it isn't: a helicopter. While the aircraft has impressive credentials, the winged design limits its ability to navigate into tight areas the way the current Black Hawk can.

The Defiant needs to play catch-up

Lockheed Martin's Defiant design looks much more like a traditional helicopter, but with a few noticeable differences: The aircraft employs a dual-rotor system, designed to improve stability and allow for higher speeds, and a rear-mounted pusher propulsor to generate that added velocity.

The coaxial rotor design has been around for a century, but it is tough to get right because the amount of torque created causes significant turbulence and maneuverability issues. Sikorsky, working with Boeing, has attempted to use software to minimize these, but design difficulties caused the aircraft's first flight to be delayed by two years.

The Defiant hovers over a tree line during its first test flight.

The Defiant in the air. Image source: Lockheed Martin.

If the new design works to plan, the two blades working together provide the stability to allow for higher speeds -- purportedly as high as 240 knots -- while maintaining a helicopter's advantage of operating in confined spaces.

Sikorsky is well behind the V-280 in terms of total flight time, and the company has a lot of work to do to prove the endurance of its design before it can even demonstrate features, like autonomous flying, that the V-280 has already shown. But if the new design works as planned, it could offer the speed of an airplane without the design compromises.

May the best bird win

The V-280 and Defiant now have about two years to show the Army what they can do. On paper the V-280 would appear to be the front-runner because it seems more adept at taking over the Black Hawk's traditional role of transporting troops and cargo and flying long-range missions, but the Defiant design has great potential if Sikorsky's engineers can get it flying to its potential.

One thing that is clear is that the Army is going to be spending a lot of money on helicopter replacements in the years to come. In addition to competing for the FLRAA program, Lockheed and Textron are also among five teams, along with a separate team from Boeing and competitors backed by Northrop Grumman and L3 Harris, for the separate Army Future Attack and Reconnaissance Aircraft (FARA) award to replace the Army's Apache attack helicopter. A good showing by the Defiant in the FLRAA competition could help prove the potential of the dual rotor for other competitions.

The FARA competition will likely be narrowed to two teams in the months to come. They will compete for a total contract value perhaps half that of the FLRAA, but it would still be a significant prize for whichever defense contractor is the eventual winner.

More broadly, the competitions will say a lot about how the Army views competing visions of what the future of helicopter operations looks like. Bell needs success to give its parent Textron a jump start, while Sikorsky, if successful, would go a long way toward justifying the $9 billion Lockheed paid for it in 2015.