94 November 2018 //^ http://www.combataircraft.net
TAKING A LOOK BEHIND THE HEADLINES
BYBY ROBERT BECKHUSEN ROBERT BECKHUSEN
XXXXXXXXX...
94 November 2018 //^ http://www.combataircraft.net
DISPATCHES FROM THE FRONT LINE
OF AEROSPACE TECHNOLOGY
BY DAVID AXE
US NAVY CARRIER
DRONE HAS DEEP
STEALTH ROOTS
T
HE US NAVY’S new MQ-25A Stingray
aerial refueling drone bears an
uncanny resemblance to an
experimental US military aircraft from
the late 1970s. And that similarity
could point to the way for the
Stingray’s potential evolution from a tanker into
a stealthy surveillance and strike aircraft.
On August 30, the navy awarded Boeing an
$805-million contract for the construction of the
irst four MQ-25s. The service hopes to acquire
as many as 72 MQ-25s as part of a $5-billion
acquisition efort.
The Stingray should begin assuming tanking
duties aboard the navy’s 10 aircraft carriers in the
mid-2020s, freeing up F/A-18E/F strike ighters
currently handling the refueling mission. But it
could do more than merely refuel other aircraft.
The carrier-based aerial refueling system (CBARS)
competition that produced the Stingray is just
the latest version of a drone development efort
dating to the early 2000s. For more than a
decade, it aimed to ield carrier-launched drones
for air-to-ground attack missions and intelligence,
surveillance and reconnaissance, or ISR.
To save money and simplify development, the
navy in 2016 decided its irst carrier drone would
be a tanker. ‘The intent is to signiicantly reduce
development timelines from contract award to
initial operational capability by ive to six years’, it
explained in a statement. ‘By reducing the
number of key performance parameters to
mission tanking and carrier suitability, industry
has increased lexibility to rapidly design a system
that meets those requirements.’
But a year later, there was still talk of the MQ-25
eventually growing back into its original attack
and ISR roles.‘The navy expects to provide primarily aerial
refueling and ISR capabilities irst, while using
open systems standards to support incremental
capability upgrades in the future like adding the
capability to receive fuel, weapons and improving
radars’, the Government Accountability Oice
explained in a 2017 report.
Boeing clearly expects the MQ-25 to grow.
While the tanking mission doesn’t require
signiicant stealth, ISR and attack missions do
require stealth. And the Stingray’s airframe is
inherently low-observable. After all, it shares key
features with the Tacit Blue stealth demonstrator
that irst lew in 1978.
Built by Northrop Grumman and overseen by
the Defense Advanced Research Projects Agency,
Tacit Blue embodied a new approach to radar
low-observability. DARPA’s previous stealth
demonstrators, built under the Have Blue
program that ended in 1979, relied on a heavily
faceted airframe to scatter radio waves and avoid
returning a clear radar signal. By contrast, Tacit
Blue tested curved surfaces and a unique,
top-mounted air inlet to achieve the same efect.
The Tacit Blue demonstrator, now residing at
the National Museum of the US Air Force in Ohio,
is 56ft long — 15ft longer than the MQ-25 — and
has a one-person cockpit. Other than that, thetwo aircraft are eerily similar, with similar thin,
gently swept wings; outward-canted twin
‘butterly’ tails; smooth, round contours and lush,
dorsal inlets. ‘Like a butter dish with wings’,
according to Northrop.
DARPA pitched Tacit Blue as a stealthy
battleield surveillance aircraft. But the butter-
dish airplane, known to its creators and crews as
the ‘Whale’, proved inicky. ‘Many engineering
problems had to be overcome’, Northrop stated.
For one, Tacit Blue was extremely diicult to ly.
‘You’re talking about an aircraft that at the time
was arguably the most unstable aircraft man had
ever lown’, John Cashen, a Northrop engineer
who worked on Tacit Blue and many of the
company’s other stealth aircraft designs, told Air
Force Magazine.
When the Boeing 707-based E-8 proved to be
safer, cheaper and more efective for battleield
surveillance, the air force and Northrop instead
mined Tacit Blue’s technology to support other
development eforts. ‘The program turned into a
testbed because its low-observable technologies
proved to be more valuable than its [mission]
contribution’, George Muellner, then an air force
lieutenant general, said during Tacit Blue’s public
unveiling in 1996.
Tacit Blue contributed to the development of
the B-2 stealth bomber, helping to give the
bigger aircraft its smooth, round shape and
buried inlets. Northrop’s YF-23 stealth ighter
demonstrator borrowed Tacit Blue’s tail and
engine outlet design.
If Tacit Blue could evade detection by radar, so
could the MQ-25. If Tacit Blue could inform the
design of a stealth bomber and stealth ighter, it
could also inform the evolution of the MQ-25
into a radar-evading surveillance and
attack drone.
The Stingray could become much more than
just a tanker. It already has the shape for it.While the tanking
mission doesn’t
require significant stealth,
ISR and attack missions
do require stealth. And
the Stingray’s airframe is
inherently low-observable
Over a three-year period
beginning in 1982, Tacit
Blue proved that Northrop’s
technological breakthroughs
in low observables were real,
paving the way for the B-2A
bomber and other stealthy
designs. Northrop Grumman