Tacit Blue


    Below is an article on Tacit Blue that Kurt Lammon copied off the web somewhere. I'd like to attribute it to someone, but I don't know the author's name. There are a couple more articles that you can access by clicking the links below.


News Release by U.S. Department of Defense on the Tacit Blue


    The US Air Force, Defense Advanced Research Projects Agency, and Northrop Corp. teamed up for the TACIT BLUE Technology Demonstration Program from 1978 to 1985. TACIT BLUE validated a number of innovative stealth technology advances. Most notably, it was the first aircraft to demonstrate a low radar cross section using curved surfaces, along with a low probability of intercept radar and data link. TACIT BLUE initially was created to demonstrate that a low observable surveillance aircraft with a low probability of intercept radar and other sensors could operate close to the forward line of battle with a high degree of survivability. Such an aircraft could continuously monitor the ground situation behind the battlefield and provide targeting information in real-time to a ground command center.


    TACIT BLUE was developed as a potential platform for radar sensors developed under the Air Force Pave Mover and Army SOTAS programs. In 1982, the Undersecretary of Defense for Research and Engineering (USDRE) combined the SOTAS and Pave Mover efforts into a joint program, later designated Joint STARS. From 1982-1984, the services, OSD, and Congress wrestled over the development of requirements for the joint program, as well as the appropriate platform for the sensor. At the time, one option under active consideration was a two-phased program in which the radar would initially be deployed on ten conventional aircraft, with subsequent production focused on a stealth platform derived from the TACIT BLUE test aircraft. In May 1984, the Chiefs of Staff of the Air Force and Army made the final decision to put the Joint STARS radar on a 707 platform.


    The men responsible for the design of the Tacit Blue, Irv Walland (aerodynamist), Steve Smith (program manager) and John Cashen (electromagnetist)


   
TACIT BLUE was one of the most successful technology demonstrator programs in Air Force history, meeting all program objectives and most low observable and sensor performance goals. The aircraft made its first flight in February 1982, and subsequently logged 135 flights over a three year period. The aircraft often achieved three to four flights weekly and several times flew more than once a day.


    TACIT BLUE featured a straight, tapered wing with a Vee tail mounted on an oversized fuselage with a curved shape. It had a wingspan of 48.2 feet and a length of 55.8 feet and weighed 30,000 pounds. A single flush inlet on the top of the fuselage provided air to two high-bypass turbofan engines. TACIT BLUE employed a quadruply-redundant, digital fly-by-wire flight control system to help stabilize the aircraft about the longitudinal and directional axes.


    The TACIT BLUE program cost approximately $165 million and covered development, construction and flight test. As the prime contractor, Northrop received a $136 million contract to provide one complete technology demonstrator and a partially-developed back-up airframe. The program provided valuable engineering data that aided in the B-2 "Spirit" design.


 

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updated 2/31/2002