img

Summary

Advanced Tactical Aircraft ATA “A/B”

By June 1977 a special project office had been established with strong support from Secretary of Defense Harold Brown and Director of Defense Research and Engineering (DDR& E) William J. Perry. The overall goal of the USAF low observables program was to develop the recently demonstrated breakthrough into a set of new capabilities for U.S. armed forces, as rapidly as possible in total secrecy. A hand-picked staff of five officers were breifed into “Have Blue” and “hidden” within AF/RDPJ, Room 5D156, the strategic reconaissance office at USAF Headquarters in the Pentagon. These officers were Col Dave Williams, Maj Ken Staten, Maj Joe Ralston, Maj Bob Swarts, and Maj Jerry Baber.

The project office studied several potential applications of low observables technology, and a small number of specific programs were soon initiated. The second one of these was a manned strike aircraft. Maj. Ken Staten became the acting program manager for the strike aircraft, which during its conceptual stages bore the very nonspecific label of Advanced Technology Aircraft (ATA). During 1977 DARPA developed two sets of preliminary requirements for ATA. A formal concept definition contract for $11.1 million was awarded to the Skunk Works on October 10, 1977, for a one year study based on the two sets of requirements.

ATA “A”

The ATA “A” proposal was a “small” F-15 sized single-seat , twin engine, attack aircraft, intended to carry a 5000 lb. payload (two 2000 lb weapons plus suspension equipment) a range of 400 n miles.

ATA “B”

The ATA “B” proposal was a larger two seat, four engine, bomber closer in size to the F-111. It would carry a 10,000 lb. payload on a 1000 n mile mission.

By February 1978, the payload for the “B” model was reduced to 7500 lb. Early sizing studies had indicated that the “B” model would need six engines, not just four, to achieve its original range-payload goals. This is because an aircraft’s gross weight grows roughly exponentially as a function as its design range. As the design range increases, so does the rate of weight growth. It simply would not be practical to biuld a large, longe range aircraft with the low lift-to-drag ratio (L/D) of Have Blue. Although a higher L/D could have been achieved through various design changes, some Air Force officials and even some designers and managers at Lockheed believed that the Have Blue breakthrough was a result of “Black Magic” rather than science. These individuals strongly resisted any significant departures from the basic Have Blue configuration. As a result, it was neccessary to reduce the payload of the “B” model to keep the aircraft’s size somewhat resonable.

Characteristics of ATA “A” and ATA “B” (February 1978) ATA “A” ATA “B” Mission radius 400 n mile 1000 n mile Payload 5000 lb 7500 lb TOGW 43,000 lb 90,000 lb Length 64 ft 76 ft Wingspan 43 ft 47 ft Crew 1 2 Number of engines 2 2 Engine type GE F404 (nonafterburning variant) GE F101 (“partially” afterburning) Cost x 1.5x ???

In June 1977 President Jimmy Carter had canceled the B-1A bomber program. Filling the B-1’s role became a critical objective for the USAF during the next several months, and this focused attention on the “B” model of ATA. If the ATA “B” plan was pursued, the engines for research, developement, testing, and evaluation would be “cannibalized” from the canceled B-1A program. Although this larger version became a strong favorite with the Strategic Air Command (SAC), Lt. Col Joe Ralston and Lt. Col Ken Staten at RDPJ voiced the realistic, but in some quarters unpopular, view that the “B” model was not technically feasible at the time.

This opinion was based on the risks inherent in scaling the Have Blue concept up to a size as large as the ATA “B”. As noted earlier, even though the requirements had been relaxed, the designers knew that the “B” was right at the upper bound of what was realistically possible. (Their conviction was reinforced during a visit to Lockheed’s Rye Canyon research facility. Col. Williams, Lt. Col Ralston, and Lt Col Staten each made five takeoff attempts with the ATA “B” on Lockheed’s flight simulator. According to Lt. Col Jerry Baber, “Ralston saved it once; all other attempts resulted in the loss of the [simulated] aircraft.” All three men were experienced fighter pilots.)

After the payload weight had been reduced to 7500 lb, another difficulty involved insufficient justification for the added cost and risk of the “B”. Ralston and Staten recommended deferring the bomber and focusing on the smaller attack aircraft. SAC headquarters did not like this, but Gen David C. Jones, who had become chairmen of the Joint Chief of Staff, backed up Ralston and Staten on the basis that valuable information might be gained from pursuing the lower-risk, less expensive “A” model before attempting to build a larger bomber. This was also the path that would introduce a low observable weapon system into the operational inventory as rapidly as possible, consistent with the overall goals of the USAF low observables program.

In the summer of 1978 USAF officials decided to discountinue the “B” and to take the “A” model Advanced Technology Aircraft into full-scale developement. On November 16,1978, Lockheed was awarded a contract for five full scale development (FSD) aircraft under the code name “Senior Trend”.

ATB

The ATA “B” later resurfaced as the Advanced Technology Bomber (ATB). Fresh with their Tacit Blue research, Northrop submitted an unsolicited proposal causing yet another poleoff compition with Lockheed for the ATB. Northrop won that compitition by a slim margin and went on the produce the ATB, now known as the B-2 “Spirit” Stealth Bomber.

Source

HAVE BLUE And The F-117A: Evolution Of The "Stealth Fighter"

David C. Aronstein and Albert C. Piccirillo AIAA/ANSER, Arlington, VA 1997

Sources

http://www.f-117a.com/ATA.html