Tacit Blue

Role	Stealth demonstrator Type of aircraft
Manufacturer	Northrop Corporation
First flight	February 5, 1982
Retired	1985
Status	Retired
Primary user	United States Air Force
Number built	1

The Northrop Tacit Blue was a technology demonstrator 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

[edit]

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.

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 and other sensors that could operate close to the forward line of battle with a high degree of survivability.

Tacit Blue represented the "black" component in the larger "Assault Breaker" program, which intended to validate the concept of massed standoff attacks on advancing armored 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.^[1]

The radar sensor technology developed for Tacit Blue evolved into the radar now being used by the E-8 Joint STARS aircraft.^[2]

Tacit Blue was given the cover designation of "YF-117D" by the Air Force.^[3]^[4]

Design

[edit]

Tacit Blue, nicknamed "the whale" (and sometimes also called an "alien school bus" for its only slightly rounded-off rectangular shape),^[8] featured a straight tapered wing with a V-tail mounted on an oversized fuselage with a curved shape. It was the first stealth aircraft to feature curved surfaces for radar cross-section reduction.^[9] Northrop would use this stealth technology on the B-2 bomber. 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 flight control system to help stabilize the aircraft about its longitudinal and directional axes.

Operational history

[edit]

The aircraft made its first successful flight on February 5, 1982, in Area 51, at Groom Lake, Nevada, flown by Northrop test pilot Richard G. Thomas.^[7] 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.^[10]

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 at Wright-Patterson Air Force Base, near Dayton, Ohio and has been on display in the fourth hangar at the museum since June 2016.^[11]

Specifications

[edit]

Data from the National Museum of the United States Air Force and the Department of Defense

General characteristics

Crew: 1
Length: 55 ft 10 in (17.02 m)
Wingspan: 48 ft 2 in (14.68 m)
Height: 10 ft 7 in (3.23 m)
Airfoil: Clark Y mod.^[12]
Gross weight: 30,000 lb (13,608 kg)
Powerplant: 2 × Garrett ATF3-6 turbofan engines, 5,440 lbf (24.2 kN) thrust each

Performance

Maximum speed: 250 kn (290 mph, 460 km/h)
Service ceiling: 25,000–30,000 ft (7,600–9,100 m) operating altitude
Thrust/weight: 0.36

References

[edit]

^ Assault Breaker Program Analysis.
^ Ramon Lopez (8 May 1996). "Out of the black comes Tacit Blue". Flight Global.
^ von Ehrenfried, Manfred "Ductch" (2013). Stratonauts: Pioneers Venturing into the Stratosphere. New York: Springer. p. 204. ISBN 978-3319029009.
^ "Cover Designations for Classified USAF Aircraft". www.designation-systems.net. Retrieved 2024-04-22.
^ Vartabedian, Ralph (26 February 1993). "Job Stress Catches Up With 'Dr. Stealth' of Aerospace : Science: Eccentric genius John Cashen's departure for Australia has many questioning the technology's future". L A Times. Retrieved 28 August 2018.
^ "Tacit Blue". CNet News. Photos: A brief history of stealth aircraft. November 23, 2007. Archived from the original on September 7, 2012. Retrieved 2 May 2012.
^ ^a ^b Grier, Peter (August 1996). "The (Tacit) Blue Whale". Air Force Magazine. Retrieved 25 August 2018.
^ Rogoway, Tyler (March 1, 2014). "Lockheed's Senior Peg: The Forgotten Stealth Bomber". Jalopnik.
^ Merlin, Peter W. (2011). Area 51. Arcadia Publishing. p. 119. ISBN 978-0738576206.
^ Patterson, Thom (February 2014). "Area 51 Spy Plane and Other Aviation Tales". CNN. Retrieved 25 June 2020.
^ National Museum of the USAF Fact Sheet
^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.

External links

[edit]

Wikimedia Commons has media related to Northrop Tacit Blue.

Northrop aircraft and aircraft engines

Manufacturer
designations

'Greek' series	Alpha Beta Gamma Delta
'N' series	Note: Northrop company designations include a wide variety of technologies. Only aircraft, aero engines, and missiles are linked here. N-1/M N-2 N-3 N-4 N-5 N-6 N-7 N-8 N-9/M N-10 N-12 N-14 N-15 N-16 N-18 N-19 N-20 N-21 N-23 N-24 N-25A/B N-26 N-29 N-31 N-32 N-34 N-35 N-36 N-37 N-38 N-39 N-40 N-41 N-45 N-46 N-47 N-48 N-49 N-50 N-51 N-52 N-54 N-55 N-59 N-60 N-63 N-65 N-67 N-68 N-69 N-71 N-72 N-73 N-74 N-81 N-82 N-84 N-86 N-87 N-94 N-96 N-102 N-103 N-105 N-110 N-111 N-112 N-117 N-124 N-132 N-133 N-134 N-135 N-138 N-141 N-144 N-149 N-150 N-151 N-155 N-156 N-165 N-204 N-205 N-250 N-251 N-267 N-285 N-300 N-301 N-302 N-303 N-304 N-305 N-306 N-307 N-311 N-320 N-321 N-322 N-330 N-353 N-370 N-381
'P' series	P530 P600 P610 P630

By role

Attack	YA-13 XA-16 A-17/Nomad N-3PB YA-9
Bombers	YB-35 YB-49 B-62 BT B2T B-2
Drones	Q-4
Fighters	3A XP-56 P-61 XP-79 F-89 XFT F2T F-5/CF-5/CF-116 YF-17 F-18L F-20 YF-23
Reconnaissance	F-15 RF-61 RF-5 N-165 N-204
Trainers	T-38
Transports	Alpha Beta Gamma Delta C-19 C-100 YC-125 RT
Experimental	N-1M N-9M JB-1 MX-324 MX-334 M2-F2 M2-F3 HL-10 Tacit Blue X-4 X-21

Aircraft
engines

XT37

Names

See also: TR-3

USAAS/USAAC/USAAF/USAF fighter designations 1924–1962, and Tri-Service post-1962 systems

1924 sequences
(1924–1962)

Pursuit (1924–1948)	P-1 P-2 P-3 P-4³ Curtiss P-4 Boeing P-4 P-5 P-6 P-7 P-8 P-9 P-10 P-11 P-12 P-13 P-14 P-15 P-16 P-17 P-18 P-19 P-20 P-21 P-22 P-23 P-24 P-25 P-26 P-27 P-28 P-29 P-30 P-31 P-32 P-33 P-34 P-35 P-36 P-37 P-38 P-39 P-39E P-40 P-41 P-42 P-43 P-44 P-45 P-46 P-47 P-48 P-49 P-50 P-51 P-52 P-53 P-54 P-55 P-56 P-57 P-58 P-59³ XP-59 P-59 P-60 P-61 P-62 P-63 P-64 P-65 P-66 P-67 P-68 P-69 P-70 P-71 P-72 P-73² P-74¹ P-75 P-76 P-77 P-78 P-79 P-80 P-81 P-82 P-83 P-84 P-85 P-86 P-87 P-88 P-89 P-90 P-91 P-92
Fighter (1948–1962)	F-38 F-39 F-40 F-47 F-51 F-59 F-61 RF-61C F-63 F-80 F-81 F-82 F-83 F-84 F-84F/J F-84H F-85 F-86 F-86C F-86D/G/K/L F-87 F-88 F-89 F-90 F-91 F-92 F-93 F-94 F-95 F-96 F-97 F-98 F-99 F-100 F-100B F-101 F-102 F-102B F-103 F-104 XF-104 F-104S NF-104A F-105 F-106³ XF-106 F-106 F-107 F-108 F-109² F-110 F-111 F-111B F-111C F-111K AFTI/F-111A EF-111A
Pursuit, biplace	PB-1 PB-2 PB-3
Fighter, multiplace	FM-1 FM-2
Non-sequential	F-24 P-322 P-400

Tri-service sequence
(1962–present)

Main sequence	F-1 F-1C/D F-1E/F F-2 F-3 F-4 F-4K/M F-5 G F-6 F-7 F-8 F-9 F-9F–J F-10 F-11 F-12 F-12C² F-13¹ F-14 F-15 F-15E F-15EX F-15J F-15 STOL/MTD F-16 F-16XL NF-16D F-17 F/A-18 F/A-18E/F EA-18G F-19¹ F-20 F-21 F-22 YF-22 FB-22 F-23
Non-sequential	F-35 F-35I X-35 F-117

Covert designations

Related designations

FV-12

¹ Not assigned • ² Unofficial • ³ Assigned to multiple types
See also: "F-19" • 1919–1924 sequence

Stealth aircraft

Stealth technology

United
States

Experimental	Boeing Model 853-21 Quiet Bird Boeing–Sikorsky RAH-66 Comanche Boeing Bird of Prey Boeing X-32 Boeing X-45 F-19 Lockheed Have Blue Lockheed YF-22 Lockheed Martin FB-22 Lockheed Martin X-35 Lockheed Martin X-44 MANTA McDonnell Douglas A-12 Avenger II Northrop Tacit Blue Northrop Grumman X-47B Northrop YF-23
Fighters	Lockheed Martin F-22 Raptor Lockheed Martin F-35 Lightning II
Attack	Lockheed F-117 Nighthawk
Bombers	Northrop B-2 Spirit Northrop Grumman B-21 Raider
UAVs	General Atomics MQ-20 Avenger Boeing MQ-25 Stingray Boeing MQ-28 Ghost Bat Boeing Phantom Ray Lockheed Martin Sea Ghost Lockheed Martin RQ-170 Sentinel Northrop Grumman RQ-180 Kratos XQ-58 Valkyrie General Atomics XQ-67A
Programs	Advanced Tactical Fighter F/A-XX Joint Strike Fighter Light Helicopter Experimental Long Range Strike Bomber Next Generation Air Dominance Next-Generation Bomber

China

Fighters	Chengdu J-20 Shenyang FC-31
Bombers	Xian H-20
UAVs	Hongdu GJ-11 AVIC Dark Sword CAIG Wing Loong-10 CASC Rainbow-7 FL-71

Russia

Experimental	Yakovlev Yak-43 Sukhoi Su-47 Mikoyan Project 1.44
Fighters	Mikoyan LMFS Mikoyan PAK DP Sukhoi Su-57 Sukhoi Su-75 Checkmate Sukhoi/HAL FGFA
Bombers	Tupolev PAK DA
UAVs	Mikoyan Skat Sukhoi S-70 Okhotnik-B

United
Kingdom

Experimental	British Aerospace P.125 BAE Systems Replica
Fighters	Global Combat Air Programme
UAVs	BAE Systems Taranis

Japan

Experimental	Mitsubishi X-2 Shinshin
Fighters	Global Combat Air Programme

Italy

Fighters	Global Combat Air Programme

India

Fighters	HAL AMCA Sukhoi/HAL FGFA
UAVs	DRDO Ghatak

France

Fighters	Future Combat Air System
UAVs	Dassault nEUROn

Spain

Fighters	Future Combat Air System
UAVs	Dassault nEUROn EADS Barracuda

Germany

Experimental	MBB Lampyridae
Fighters	Future Combat Air System
UAVs	EADS Barracuda Airbus Wingman

Sweden

Fighters	Flygsystem 2020

Turkey

Fighters	TAI TF Kaan
UAVs	Bayraktar Kızılelma TAI Anka-3

Indonesia

Fighters	KAI KF-21 Boramae

South Korea

Fighters	KAI KF-21 Boramae

Iran

Fighters	IAIO Qaher-313 HESA Shafaq