Beginning in 1962, the Model 147 was introduced as a reconnaissance RPV (Remotely Piloted Vehicle, nomenclature of that era) for a United States Air Force project named Fire Fly.

Over the next decade – assisted with secret funding from the recently formed National Reconnaissance Office along with support of the Strategic Air Command and Ryan Aeronautical's own resources[1] – the basic Model 147 design would be developed into a diverse series of variants configured for a wide array of mission-specific roles, with multiple new systems, sensors and payloads used, modified and improved upon during the operational deployment of these drones in Southeast Asia.

At the end of the Vietnam War in 1975 the U.S. military's available funding and need for combat drones severely declined, even as Teledyne Ryan introduced further advanced developments of the Model 147 series such as the BGM-34 strike and defense suppression RPVs.

Ryan engineers concluded they could increase the Firebee's range to allow it to fly south over the Soviet Union after launch from the Barents Sea, with recovery in Turkey.

The Model 136, or Red Wagon, was optimized for the role with long straight wings for high-altitude flight, an engine set on the back of the fuselage to reduce its radar and infrared signatures as seen from below, and inward-canted twin tail fins to conceal the exhaust plume.

Ryan then proposed another drone project named "Lucy Lee" consisting of a highly modified Firebee intended to perform photographic and signals intelligence (SIGINT) reconnaissance from outside Soviet airspace.

After four successful test flights performed in April and early May 1962, the third and fourth Model 147As (which were almost identical to the second example) were declared operational and deployed at Holloman Air Force Base in New Mexico with a Lockheed DC-130 Hercules launch aircraft.

The system injected chlorosulfonic acid into the engine tailpipe when the drone entered hostile territory, creating tiny ice crystals which formed a transparent contrail.

The drones were mounted under the wings of their DC-130 Hercules controller aircraft, its propellers turning, at ready on the runway when notification came from Air Force Chief of Staff Curtis LeMay that the mission was scrubbed.

The SA-2 was also radio-controlled to the target by a ground command guidance link, with the missile carrying a transponder that sent back a signal to the Fan Song radar to allow tracking.

A special "SAM sniffer" Radar MASINT payload was installed on the Fire Fly to pick up these signals, with the drone relaying the data to an ERB-47H electronic warfare aircraft.

While the fledgling Ryan Model 147 drones had thus far played only backstage roles, U.S. relations with China and North Korea and events in Southeast Asia would significantly ramp up their operational involvement in the next decade.

Ryan Aeronautical's engineering expertise and feedback from the USAF's operational experience with the drones would also cause them be continually modified, redesigned and optimized for better performance, and further developed to take on an array of new missions.

With every shoot-down, the Chinese issued verbose press reports praising China's "great victory" in shooting down "reconnaissance planes of the imperialist United States."

Although self-destruct charges were considered for installation on overflight Lightning Bugs it was finally decided not to, and the United States simply adopted a policy of "no comment" when asked about the reconnaissance drones.

The information was immediately put to use to develop a simple warning system that would tell the pilot when an SA-2 command signal was turned on, meaning a missile launch was imminent; this device would go into production as the AN/APR-26.

Despite these drawbacks the Air Force did obtain useful intelligence from the drone's cameras even when they were not on target, as well as some minor psychological warfare effect from the startling bright strobe flashes, and felt that the concept was worth further development.

[3] While they were a good asset to USAF capabilities during Operation Rolling Thunder, these medium-altitude Combat Angel ECM RPVs saw little use after the November 1968 official halt to air strikes on North Vietnam.

Strategic Air Command's Buffalo Hunter program was implemented to conduct low altitude photographic reconnaissance in Southeast Asia using unmanned aircraft, particularly for time-sensitive targets such as military airfields and suspected SAM sites in North Vietnam.

The SD was externally similar to its SC predecessor with a slightly different nose shape and systems package; 87 of the Model 147SD were built under the Air Force's Compass Bin and Buffalo Hunter programs.

[4] Some 147SDs were converted to the Model 147SDL which featured a navigation system that obtained position information from the LORAN radio location network, providing the drone with greater accuracy.

One Model 147SD served as a testbed for the USAF's Compass Robin program, which aimed to develop expendable radio frequency sensors that could be covertly ejected from RPVs or drones in areas defended by Soviet SA-2 Fan Song radars and thus provide the capability to collect electronic intelligence information.

Its main improvement was a more powerful engine, the Teledyne CAE J100-CA-100 with 2,800 pounds of thrust (1,270 kgp) which allowed the drone to operate at higher altitudes up to almost 75,000 feet (23 km).

The Model 147SC was the workhorse for low-altitude reconnaissance during this period; in December 1972 during Operation Linebacker II the USAF depended almost entirely on the Buffalo Hunter AQM-34L/M RPVs for bomb damage assessment due to bad weather.

A series of fast-track adaptations of an existing target drone resulted in a system whose effectiveness was beyond expectations, even with guidance technology that was extremely crude by 21st century standards.

Teledyne Ryan proposed follow-on drone variants based on the Model 147 series which could undertake various tactical strike and defense suppression missions, and also carry and deliver precision-guided munitions.

Eight BGM-34Bs with more powerful Teledyne CAE J69-T-41A 1,920 pounds-force (8.5 kN) thrust engines were also built and evaluated, including a 'Pathfinder' version with laser designator and low light level TV (LLLTV) camera in its Philco-Ford nose pack.

Six Model 147SC / AQM-34L drones were fitted with upgraded Lear Siegler avionics in 1972, redesignated YAQM-34U and five of these would later become BGM-34C multi-mission RPVs using modular nose and fuselage equipment and systems packages.

In the late 1990s Teledyne Ryan, using company funds, configured two Firebees with cameras and communications electronics to provide real-time intelligence for battlefield target acquisition and damage assessment.

These two UAVs, each named Argus, were used in a USAF "Green Flag" exercise to relay images in real-time from the test range in Nevada to Air Force officers in Florida.