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AQM-91 Firefly / Compass Arrow

The Ryan-built Firefly Model 154 COMPASS ARROW, first of the second generation of UAVs, was designed for high-altitude, low-detectability reconnaissance. It flew at 78,000 feet and incorporated many early 'stealth' techniques. It could fly a 2000-mile mission, self-navigated by a Doppler Inertial guidance system and on-board computer. Twenty eight were produced, but after the rapprochement with China in the early 1970s which ended aerial overflight reconnaissance, they did not become operational.

Ryan Aeronautical developed a reconnaissance UAV capable of penetrating deep into Chinese airspace: the Model 154, (also known as the Compass Arrow, or Fire Fly). Instead of flying extremely high-speeds like the D-21, the Fire Fly possessed a unique design that made it nearly impossible to pick up on radar. Such accomplishments continued with the design and development of high-altitude surveillance vehicles such as the Compass Arrow and Compass Cope aircraft. These developments long ago demonstrated and documented capabilities which today are available in times of peace or war and for use in military, industrial, or commercial venture.

Another outlandish UAV system designed for reconnaissance operations over China was the project called Lone Eagle, later renamed Compass Arrow. Perhaps the key point about Compass Arrow is that it represents the only true follow-on UAV ever produced by the US. SAC wanted the completely new Compass Arrow to take over for the high altitude modified Lightning Bug drone that had proved vulnerable to enemy missiles. The new design incorporated such highly sophisticated technologies that a SAC reconnaissance historian said it represented “a revolutionary development in the evolution of the special purpose aircraft.”

Officials at Air Force Systems Command, which represented the “normal” or “white world” of the Air Force acquisition system, had become so enthusiastic about the growth potential for drone reconnaissance that they attempted to wrest drone development from the NRO and the special acquisition arrangement with Air Force Logistics Command’s Big Safari office. Systems Command believed that NRO drone management encouraged cozy “sole-source” (non-competitive) contracts that led to unnecessary cost escalation. Moreover, they felt normal acquisition practices would incorporate normal Air Force standardization and maintainability features that would minimize contractor involvement in operations and result in lower operations and maintenance costs.

NRO Director Al Flax, thought by many to be one of the most important advocates of drones in that era, fought hard for NRO and Big Safari cognizance over Compass Arrow. Still, AFSC’s Reconnaissance/Strike office gained control and awarded the contract in June 1966. The Air Force invited two companies; North American and Ryan Aeronautical to compete for the lucrative contract that included 100 production vehicles, which Ryan (maker of the Lightning Bug series drones) won.

Like the D-21, Compass Arrow was an “ultimate” design that soon ran into the cost-capability conundrum that afflicts so many UAV programs. It was built to do the job right, but the price was too high even for the NRO. Although the “silver bullet” nature of the Lightning Bug drone program had resulted in high unit costs, standard acquisition practices proved even less efficient. Like the D-21, Compass Arrow was built for the trip to Lop Nor, and its capability goals were high. The challenges of autonomous flight at the required altitudes (80,000 feet) and distances pushed the stateof-the-art and the program quickly exceeded its budget and projected operational date. The original development program was bid at $35 million, but contractors later admitted they knew actual costs would be much higher.

A company publication explained the huge cost escalation experienced by the program by saying, “The 154 [the company designation for Compass Arrow] was a victim of too much optimism in the heat of a very tough competition to get the business.” Only one year after the contract was awarded, the NRO cut the production number from 100 to a lean 20 airframes.

Ryan deliberately under-bid to get the job, counting on the support of the highly secretive NRO community to bail them out when the inevitable escalation occurred. The contractor under-bid not only in terms of cost but also in time requirements. The planned times needed to reach an operational configuration were extremely short, based as they were on the rapidity of modifications in the Lightning Bug program. Although the NRO had achieved some success with the technologically challenging, Mach 3+ SR-71 program, the task of making this drone actually work exceeded the bounds of the technology of that era.

Originally planned to be an 18-month program, Compass Arrow took five years to yield 20 production airframes, at a final cost of $250 million, which equates to almost $1.7 billion in FY10 dollars. The unit cost of $65 million makes Compass Arrow one of the most expensive drone aircraft ever. Competitive bidding contributed to the illusion that drones constituted a cheap alternative to manned and satellite reconnaissance.

The Viet Nam era AQM-91 Compass Arrow spyplane, arguably demonstrated an 80,000 feet flight altitude capability. Powered by a special design turbojet engine (the General Electric J97), Compass Arrow could achieve > 80 kft flying at M = 0.83 airspeed (the minimum speed giving enough inlet precompression to keep the combustor lit at that altitude). Proposals to develop a new variant of this aircraft using J97 hardware left over from the original Compass Arrow program have been considered by NASA.

The advantage of gas turbine power is that the high specific power (HP / lb) which it can develop allows high speeds and relatively high wing loading to be maintained, which reduces the aircraft's susceptibility to winds and turbulence at lower altitudes and makes for shorter flight times to conduct the mission. The disadvantages are higher fuel consumption (less range) and the exponential thrust lapse that occurs with altitude. As the air density drops the turbine engine will ingest correspondingly smaller amounts of air resulting in less power and less thrust; this eventually leads to combustor flameout. The power lapse curve typical of turbine engines illustrating this trend. As an example, the Compass Arrow's turbojet engine, capable of over 5,000 pounds of thrust at sea level, would produce only 184 pounds of thrust at 80,000 ft (Mach no. = 0.85) and would be operating on the verge of flameout.

Despite its top secret classification, the drone made headlines when it descended prematurely and landed near the perimeter of the Atomic Energy Commission complex at Los Alamos, close enough to the fence to be within view of the public. Bill Sweetman later recounted that "Aerospace Daily had hinted at the existence of the then-secret program soon after its first flight, in June 1968, but the biggest breach in security came in August 1969 when a Firefly stopped flying, and made a parachute descent into the Los Alamos National Laboratory site - landing in a picnic area that was visible from public land. Photos taken at the time allowed Aviation Week editor Barry Miller to lead a November 1970 story on RPVs with an artist's impression and three-view of the Model 154, and a detailed description."

The OSD Review Panel conducted their evaluation of the 100th SRW PCR on 26 July 1968. The majority opinion and also the one concurred with by DIA approved the entire FY 70 program as submitted by the Air Force with the exception of a level of funding identified for the out years. This included approval of the continuation of the COMPASS ARROW drone system for 12 vehicles for FY 70. Mr. Nitze commented that inclusion of the 154 drones was in contradiction to his previous decision to terminate COMPASS ARROW and to remove the 154s from the PCD.

After undergoing extensive testing by Ryan and the Air Force, President Nixon’s efforts at reconciliation with China in the early 1970s prevented the Model 154 from being used over China. On 28 July 1971, William Beecher of the New York Times reported, “Administration officials said the United States had suspended flights over Communist China by manned SR-71 spy planes and unmanned reconnaissance drones.” This was the first government acknowledgment of drone intelligence activity.

The paradoxically exotic and obsolete Compass Arrow system stood on alert at Davis-Monthan AFB, Ariz. starting in December 1971. The futility of that facesaving move was apparent, and it was not long before the project suffered an ignominious end. The NRO divested itself of the project in 1974 under NRO director John L. McLucas, part of a post-Vietnam cost-cutting effort, and the Air Force put the expensive drones in a storage hangar.

Compass Arrow project manager Schwanhausser remembers that the Israeli military attaché, Maj. Gen. Elihu Zeira, had visited the Ryan plant and later, as the chief of Israeli intelligence, made “desperate attempts” to get the shelved vehicles just prior to the 1973 Yom Kippur War. According to Compass Arrow engineer John Dale, President Nixon did not want the drones transferred to Israel and personally ordered that they be destroyed to end the issue. On 12 July 1973 Lew Allen, Jr. Major General, USAF Deputy to the DCI for the Intelligence Community, wrote to Vice Admiral Vincent de Poix, Director, Defease Intelligence Agency, that:

"Further to your telephone inquiry on ll July relative to the COMPASS ARROW drones, I want to elaborate on our interest and role in atternpting to maintain some availability of the capability.

"Recognising that COMPASS ARROW has not been used operationally, we nevertheless recognized it as a possible trade-off capability against manned platforms such as the SR-71. To that end, and taking note of the relatively low cost involved in maintainaing the system in a contingency mode, we suggested to the reconnaissance study team leader that it be a candidate for consideration in the peripheral reconnaissance study currently under way within the Departnert of Defense. The request for that study, as you know, asked that overhead and unmanned systens be considered, where feasible, as replacements for manned systerns currently being employed.

"Almost concurrent with our request for COMPASS ARROW to be considered, we were informed of the ASD(I) decision to place the system in dead storage as of the end of FY 1973. We then asked informally if implementation of this decision could be delayed for 30 days pending completion of the peripheral reconaaissance study. The response to that request was negative, with the explanation that the system had already been deactivated.

"Apparently the pace of events on the program decisionand its executions precluded further consideration in the contextwe swggested. In the absence of any overriding substantive case, we feel the general fiscai constraints warrarat the action taken."

Despite never reaching operational status, knowledge gained from the project was applied to stealth aircraft and UAV development. There remained twenty-four J97 pre-production prototype units (not fully qualified) which were surplussed to NASA following the Air Force's decision not to pursue system acquisition; these are in storage at Ames Research Center.

Whatever the reason for Compass Arrow’s demise, it was born as, and died as, a political weapon system. Politically, technologically, and from a threat point of view, Compass Arrow was doomed, rendering any internal or bureaucratic analyses moot. It would not be the last UAV crushed by externalities that even the most enthusiastic developer could not overcome.

Compass Arrow, the product of the United States’ most knowledgeable drone contractor and a conventional program office bent on efficiency, proved that the most advanced aerospace nation in the world was not up to the engineering challenge of long distance, high altitude, unmanned operation within feasible limits of time and money.

Although Compass Arrow went well over budget, it was the time delay that proved even more deadly to the concept of drone reconnaissance. NRO director James W. Plummer told an audience of drone advocates in 1975 that advances in Soviet air defenses “resulted in the system becoming obsolete before an operational mission was ever flown.” Even that point was moot, for the Nixon Administration stopped Chinese overflights in July 1971, and the Compass Arrow’s reason for being vanished before it had a chance to prove itself. As with the D-21, accelerating improvement in US satellite reconnaissance rendered the “perfect” reconnaissance drone, Compass Arrow, an expensive anachronism.

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