The Ryan Model 147 Lightning Bug is a jet-powered drone, or unmanned aerial vehicle, produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series.
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 – 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. Missions performed by the Model 147 series RPVs included high and low-altitude photographic and electronic aerial reconnaissance, surveillance, decoy, electronic warfare, signals intelligence, and psychological warfare.
The Ryan drones were designed without landing gear for simplicity and to save weight. Like its Firebee predecessor, the Model 147 could either be air-launched from a larger carrier aircraft or launched from the ground using a solid rocket booster; at completion of its mission the drone deployed its own recovery parachute which could be snatched in mid-air by a recovery helicopter (in a combat environment it was naturally not desired to recover the drone on, from or near enemy territory and ground or water impact could also cause damage to or loss of the drone or its payload).
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. Costs of maintaining the Lightning Bugs at full readiness could no longer be justified. Only by the 1990s did substantial interest, organization and funding again emerge from the U.S. Air Force and intelligence agencies to develop, acquire and widely deploy combat UAVs.
Development Ryan Model 136 Red Wagon and Lucy Lee In 1959, Ryan Aeronautical performed a study to investigate how the company's Firebee target drone could be used for long-range reconnaissance missions. 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 Firebee has a low radar cross-section, making it hard to detect. With lengthened wings, the drone would also be able to fly at high altitude, further increasing its elusiveness. It could be launched by a Lockheed DC-130, or JATO-boosted from a land site or ship.
Ryan presented its report on the studies to the U.S. Air Force in mid-April 1960. On 1 May 1960 an American Lockheed U-2 spy plane was shot down over the USSR and its pilot, Francis Gary Powers, captured. On 1 July a Boeing RB-47H reconnaissance aircraft flying an electronic intelligence mission in international airspace near the Soviet border was shot down; four of its crew were killed and the other two captured. A few days later, the Air Force awarded Ryan a US$200,000 contract to perform further studies.
Ryan conducted radar measurements on sub-scale Firebee models and determined that their radar signature could be reduced by placing a wire screen over the jet intake, painting parts of the drone with non-conductive paint, and placing radar-absorbent material pads on both sides of the fuselage. Test flights of the modified Firebees were performed in September and October 1961. Flights were given a cover story, describing the drones as high-altitude targets for surface-to-air missiles (SAMs) in case one of them came down in a public area. The flights demonstrated that the modifications did not compromise the Firebee's performance.
Ryan actually wanted to build a completely new drone, the Ryan Model 136, for the reconnaissance mission. 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. The project stalled, however as the incoming Kennedy Administration was certain to reassess many military projects and Red Wagon was put on hold.
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. Lucy Lee seemed to be on track, but was then abruptly cancelled in January 1962.
Ryan Model 147A Fire Fly Just as the whole idea of reconnaissance drones seemed to be completely dead, the USAF came to rescue the program. The Air Force selected the cheapest option, a reconnaissance drone based on a Firebee with minimal changes. A US$1.1 million contract was issued on 2 February 1962, requesting four Firebee drones modified for aerial reconnaissance. The modified Firebees were funded from a program named "Big Safari", established in the 1950s to fund fast-track conversions of existing aircraft for the reconnaissance mission. Big Safari would continue to work on reconnaissance drones during the Vietnam War, and would also assist UAV programs in later wars.
The new reconnaissance drones were designated Model 147A and codenamed Fire Fly. Specifications dictated a range and a cruise altitude of .
The first Model 147A was a standard Firebee with a new guidance system consisting of no more than a timer-programmer, a gyrocompass, and an altimeter. The Fire Fly could be programmed to fly in a certain direction at a certain altitude for a certain time, and then turn around and return the way it came. This aircraft was intended only as a demonstrator and to evaluate the new guidance system; it carried no cameras. Three test flights were performed in April 1962 and demonstrated the validity of the concept, with the drone performing a mission which ranged from New Mexico, north into Utah, and then back again with no guidance from the ground (though accompanied by a B-57 chase plane).
The second Model 147A had an "plug" inserted into the fuselage to carry an additional 68 US gallons (258 litres) of fuel, increasing overall length from to . It also had a new nose containing a camera from the U-2. 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.
Tests conducted that summer showed the drone was almost invisible to ground radar, and interceptors that were scrambled to find it ended up chasing each other. The only problem was that the drone generated a contrail, which gave it away. A "no-con" (no-contrail) program was initiated to fix the problem in subsequent variants, though apparently it wasn't fitted to the Model 147A. The system injected chlorosulfonic acid into the engine tailpipe when the drone entered hostile territory, creating tiny ice crystals which formed a transparent contrail. An effective system, although the chlorosulfonic acid was very corrosive which required use of high-grade stainless steel plumbing.
During the Cuban Missile Crisis a U-2 was shot down over Cuba on 27 October 1962 by an S-75 Dvina and its pilot killed. Afterwards the Model 147As were authorized for reconnaissance missions in place of the U-2. 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 U-2s were used for reconnaissance over Cuba instead, with missions resuming on 5 November 1962. LeMay wanted to reserve the Fire Fly for later.
Ryan Model 147B, 147C and 147D Lightning Bug
Although the Fire Fly had yet to be used operationally, the Air Force was enthusiastic enough about the concept to issue contracts for follow-on variants. The USAF ordered nine Model 147Bs, including two prototypes and seven production aircraft. The Model 147B was designed for high-altitude reconnaissance, with wingspan extended from the span of the Model 147A to , raising the 147B's operational ceiling to .
The delivery schedule for the high-altitude Model 147B was several months out, so the Air Force also ordered seven Model 147Cs, a production version of the 147A, as an interim solution. The Model 147C had a wingspan extended to , and incorporated the no-contrail system.
Three of this batch of Model 147Cs were modified to become special-purpose Model 147Ds. The 147D combined the functions of reconnaissance and the original Firebee mission of aerial target: it was to be used as bait for S-75 Dvina SAMs to obtain data on signals associated with the S-75. The SAM was targeted by a radar codenamed Fan Song and it was simple enough to pick up its signals with a normal SIGINT aircraft. The S-75 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. Picking up these radio command signals was hazardous, since they only came on when a missile was launched. The proximity fuze signal was the most dangerous because it would only be detected moments before the SAM detonated.
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. An active radar enhancement device was installed to encourage the enemy to take shots at the drone. The three Model 147Ds were delivered in December 1962. The Fire Fly code name had leaked in the meantime, so the new drones were given the codename Lightning Bug.
In July 1963, the Lightning Bugs reached full operational status, though they had yet to fly an operational mission. In late December 1963, the Air Force ordered fourteen more Model 147Bs. By this time Fidel Castro was threatening to shoot down U-2s flying over Cuba, and a May 1964 study concluded that the Lightning Bug was the best alternative. After information about the proposal leaked to the press, the U.S. administration decided to back up the U-2s with the Lockheed A-12, precursor of the SR-71 Blackbird spy plane.
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.
During this time operational deployment of Model 147 drones would be undertaken by the Air Force's Strategic Air Command and its reconnaissance wings, equipped with DC-130 launch aircraft and recovery helicopters. Continued behind the scenes support from the National Reconnaissance Office, which had allocated project funds from its outset via the classified Program D for developing airborne intelligence collection platforms, also ensured that the Lightning Bug project would grow into a full-fledged aerial reconnaissance program.
Operational history China overflights