The Northrop Tacit Blue was a
technology demonstrator
A technology demonstration (or tech demo), also known as demonstrator model, is a prototype, rough example or an otherwise incomplete version of a conceivable product or future system, put together as proof of concept with the primary purpose of ...
aircraft created to demonstrate that a low-observable
stealth surveillance aircraft with a
low-probability-of-intercept radar (LPIR) and other sensors could operate close to the forward line of battle with a high degree of survivability.
Development
Unveiled by the U.S. Air Force on 30 April 1996, the ''Tacit Blue Technology Demonstration Program'' was designed to prove that such an aircraft could continuously monitor the ground situation deep behind the battlefield and provide
targeting information in
real time to a ground
command center
A command center (often called a war room) is any place that is used to provide centralized command for some purpose.
While frequently considered to be a military facility, these can be used in many other cases by governments or businesses ...
.
In December 1976, DARPA and the U.S. Air Force initiated the Battlefield Surveillance Aircraft-Experimental (BSAX) program, which was part of a larger Air Force program called
Pave Mover. The BSAX program's goal was to develop an efficient
stealth reconnaissance aircraft with a
low probability of intercept radar
A low-probability-of-intercept radar (LPIR) is a radar employing measures to avoid detection by passive radar detection equipment (such as a radar warning receiver (RWR), or electronic support receiver) while it is searching for a target or enga ...
and other sensors that could operate close to the
forward line of battle with a high degree of
survivability Survivability is the ability to remain alive or continue to exist. The term has more specific meaning in certain contexts. Ecological
Following disruptive forces such as flood, fire, disease, war, or climate change some species of flora, fauna, ...
.
Tacit Blue represented the "
black
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ...
" component in the larger "
Assault Breaker" program, which intended to validate the concept of massed standoff attacks on advancing armoured formations using
smart munitions. The Pave Mover radar demonstrators provided the non-stealth portion of the program's
targeting system, whereas Tacit Blue was intended to demonstrate a similar but stealth capability, while validating a number of innovative
stealth technology advances.
The radar sensor technology developed for Tacit Blue evolved into the radar now being used by the
E-8 Joint STARS
The Northrop Grumman E-8 Joint Surveillance Target Attack Radar System (Joint STARS) is a United States Air Force airborne ground surveillance, battle management and command and control aircraft. It tracks ground vehicles and some aircraft, col ...
aircraft.
Tacit Blue was given the designation of "YF-117D" by the Air Force, implying it was a variant of the
Lockheed F-117 stealth fighter.
Design
Tacit Blue, nicknamed "the
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
" (and sometimes also called an "alien school bus" for its only slightly rounded-off rectangular shape),
featured a straight
tapered wing
The wing configuration of a fixed-wing aircraft (including both gliders and powered aeroplanes) is its arrangement of lifting and related surfaces.
Aircraft designs are often classified by their wing configuration. For example, the Superma ...
with a
V-tail
The V-tail or ''Vee-tail'' (sometimes called a butterfly tail or Rudlicki's V-tailGudmundsson S. (2013). "General Aviation Aircraft Design: Applied Methods and Procedures" (Reprint). Butterworth-Heinemann. p. 489. , 9780123973290) of an aircraft ...
mounted on an oversized fuselage with a curved shape. It was the first stealth aircraft to feature curved surfaces for
radar cross-section reduction.
Northrop would use this
stealth technology on the
B-2 bomber
The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying ...
. A single
flush inlet on the top of the fuselage provided air to two
medium-bypass turbofan engines. Tacit Blue employed a quadruply redundant digital
fly-by-wire
Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control ...
flight control system to help stabilize the aircraft about its longitudinal and directional axes.
Operational history
The aircraft made its first successful flight on February 5, 1982, in
Area 51
Area 51 is the common name of a highly classified United States Air Force (USAF) facility within the Nevada Test and Training Range. A remote detachment administered by Edwards Air Force Base, the facility is officially called Homey Airport ...
, at
Groom Lake, Nevada
Area 51 is the common name of a highly classified United States Air Force (USAF) facility within the Nevada Test and Training Range. A remote detachment administered by Edwards Air Force Base, the facility is officially called Homey Airport ...
, flown by Northrop test pilot
Richard G. Thomas.
The aircraft subsequently logged 135 flights over a three-year period. The aircraft often flew three to four flights weekly and several times flew more than once a day.
Another Tacit Blue test pilot, Ken Dyson, told CNN in 2014 that Northrop had manufactured additional major components for the jet, which amounted to half of a second plane. "If we lost one, we could have a second one up and flying in short order," Dyson said.
After reaching about 250 flight hours, the aircraft was placed in storage in 1985. In 1996, after Tacit Blue was declassified, it was placed on display at the
National Museum of the United States Air Force
The National Museum of the United States Air Force (formerly the United States Air Force Museum) is the official museum of the United States Air Force located at Wright-Patterson Air Force Base, northeast of Dayton, Ohio. The NMUSAF is the ...
at
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base (WPAFB) is a United States Air Force base and census-designated place just east of Dayton, Ohio, in Greene and Montgomery counties. It includes both Wright and Patterson Fields, which were originally Wilbur Wr ...
, near
Dayton, Ohio
Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater D ...
and has been on display in the new fourth hangar at the museum since June 2016.
[National Museum of the USAF Fact Sheet]
/ref>
Specifications
See also
References
External links
Tacit Blue at National Museum of USAF
Tacit Blue: The Creation of Stealth
{{Stealth aircraft
Stealth aircraft
1980s United States experimental aircraft
Code names
Tacit Blue
V-tail aircraft
Low-wing aircraft
Twinjets