* The success of drones as targets led to their use for other missions. The well-proven Ryan Firebee was a good platform for such experiments, and tests to evaluate it for the reconnaissance mission proved highly successful. A series of reconnaissance drones derived from the Firebee, known generally as "Lightning Bugs", were used by the US to spy on Vietnam, China, and North Korea in the 1960s and early 1970s. This chapter discusses the Lightning Bugs.
* In 1959, Ryan Aeronautical performed a study to investigate how the company's Firebee 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 in the north, with recovery in Turkey to the south. The Firebee was a small aircraft, and so had a low radar "signature" or "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 Hercules, or RATO-boosted from a land site or ship.
Ryan presented its report on the studies to the US Air Force in mid-April 1960. The timing was excellent. 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-47 reconnaissance aircraft flying a signals intelligence (SIGINT) 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 $200,000 USD contract to perform further studies. Ryan conducted radar measurements on subscale Firebee models and determined that their radar signature could be reduced by placing a wire screen over the jet intake to hide the spinning compressor from radar; painting parts of the drone with radar-absorbing ferrite paint; and placing radar-absorbing pads on both sides of the fuselage. Test flights of the modified Firebees were performed in September and October 1961. The flights were given a cover story, describing the drones as high-altitude targets for 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 the machine's radar and infrared signatures as seen from below, and inward-canted twin tailfins to conceal the exhaust plume. However, although the Air Force was behind Red Wagon, the project stalled. The incoming Kennedy Administration was certain to reassess many military projects, and Red Wagon was put on hold. Ryan then proposed another drone named "Lucy Lee", which was a highly modified Firebee intended to perform SIGINT reconnaissance from outside Soviet airspace. Lucy Lee seemed to be on track, but was then abruptly canceled in January 1962. The US Central Intelligence Agency (CIA) and the Air Force had been collaborating on the development of orbital reconnaissance systems -- one of the most significant if hidden aspects of the Space Race of the era -- with the CIA also developing the Lockheed A-12 Blackbird Mach 3 reconnaissance aircraft, and reconnaissance drones simply couldn't compete for funding.
The whole idea of reconnaissance drones seemed to be completely dead, but the program then was revived from the grave. One of the interesting themes in defense programs is how new military systems are often initially proposed in grand terms, with whizzy features and the latest technology. When the grand plan proves too complicated and expensive, the military then backtracks, finally ending up with a much more modest solution, often a minimal modification of an existing system. Interestingly, such compromise solutions often prove far more effective than expected.
That is exactly what happened to the reconnaissance drone program. The US National Reconnaissance Office (NRO) -- which had been established in 1961 to coordinate development of reconnaissance systems in hopes of damping CIA-USAF squabbling over the issue -- decided to do the job on the cheap, implementing a reconnaissance drone based on a Firebee with minimal changes. A $1.1 million USD contract was issued on 2 February 1962, requesting four Firebee drones modified for photo-reconnaissance. The modified Firebees were funded by the Air Force Big Safari program office, mentioned earlier; the work was performed under the cover of an ongoing budget. Big Safari would continue to work on reconnaissance drones during the Vietnam War, and would also assist in UAV programs in later wars.
The reconnaissance drones were delivered in only three months. They were designated "Model 147A" and codenamed "Fire Fly". Specifications dictated a 1,930 kilometer (1,200 mile) range and a cruise altitude of 16.8 kilometers (55,000 feet). 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 it would turn around and come back the way it came. This aircraft was intended only as a demonstrator, to evaluate the new guidance system, and carried no cameras. Three test flights were performed in April 1962 and demonstrated the validity of the concept, with the drone performing a mission from New Mexico, north into Utah, and then back again with no guidance from the ground, though the drone was accompanied by a B-57 chase plane.
The second Model 147A had a 89 centimeter (35 inch) "plug" inserted into the fuselage to carry an additional 258 liters (68 US gallons) of fuel, increasing the length from 7 meters (22 feet 10 inches) to 7.89 meters (25 feet 9 inches). It also had a new nose containing one camera, with the camera leveraged from the U-2 spyplane. Four test flights performed in April and early May 1962 proved successful, and so 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. Interceptors that were scrambled to find it ended up chasing each other. The only problem was that the drone generated a contrail that gave it away. A "no-con (no-contrail)" program was initiated to fix the problem in following variants, though apparently it wasn't fitted to the Model 147A. The no-con system injected chlorosulfonic acid into the engine tailpipe when the drone entered hostile territory. The chlorosulfonic acid created condensation nuclei that led to the formation of very tiny ice crystals, forming a transparent contrail. The scheme was effective, though chlorosulfonic acid is very corrosive and troublesome to handle, requiring use of high-grade stainless-steel plumbing.
There was the problem of finding an operational Air Force organization that would adopt the Fire Flies. The Tactical Air Command (TAC) had zero interest; the Strategic Air Command (SAC) was also disinterested at first, until the NRO team finally found the right person, Major General William H. "Butch" Blanchard. Blanchard thought it was a great idea and didn't need much convincing to pick it up and run with it.
* In the fall of 1962, American U-2 spy planes observing Communist Cuba photographed the construction of Soviet SA-2 SAM sites. The SA-2 was capable of knocking down the high-flying U-2s, and to emphasize the threat, on 9 September, on the other side of the world, a U-2 operated by the Taiwanese for the US Central Intelligence Agency (CIA) was shot down over Communist China by an SA-2. The pilot was mortally injured.
U-2 overflights of Cuba were suspended for a time, while the threat posed by the SA-2 was considered. Finally, a U-2 overflight was authorized, taking place on 13:14 October 1962. The pictures returned by the U-2 indicated that the Soviets were setting up launch sites for intermediate-range ballistic missiles that could hit American cities over much of the US. The discovery triggered an international crisis and more reconnaissance overflights. Tensions continued to rise, with both the Americans and Soviets preparing for war. On 27 October, a U-2 was shot down over Cuba by an SA-2 and its pilot killed. Orders had been given from the Kremlin that American reconnaissance aircraft were not to be fired on, but the Soviet commander in Cuba ordered it done on his own authority. This violation of the chain of command during a superpower confrontation made the Soviet top command nervous, to put it mildly, and on 28 October they hastily announced the missiles would be withdrawn.
After the destruction of the U-2 over Cuba, the Model 147As were authorized for reconnaissance missions in its place. The NRO really wanted to put the drones into operation, and they were in fact sitting on the runway under the wings of their DC-130 Hercules controller aircraft, its propellers turning, when the word came down 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 beginning again on 5 November 1962. LeMay wanted to reserve the Fire Fly for later and not tip the Reds off to its existence.BACK_TO_TOP
* Although the Fire Fly had yet to be used operationally, and in fact the Model 147As were essentially operational test items, the NRO continued to boost the concept, issuing contracts follow-on variants. The initial follow-on 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 4 meter (13 foot) span of the standard Firebee and Model 147A to 8.2 meters (27 feet), raising the 147B's operational ceiling to 19 kilometers (62,500 feet). It was intended to complement the Lockheed U-2, operating over high-threat environments.
The delivery schedule for the high-altitude Model 147B was several months out, so in the interim an order was placed for seven "Model 147Cs", production versions of the 147A. The Model 147C had a wingspan extended to 4.6 meters (15 feet), and incorporated the no-con system. Three of this batch of Model 147Cs were modified to become special-purpose "Model 147Ds". The 147Ds combined the functions of reconnaissance and the original Firebee mission of aerial target. They were to be used as bait for SA-2 SAMs to obtain data on signals associated with the SA-2.
The SA-2 SAM was targeted by a radar codenamed "Fan Song" -- it seems in part because it used two fan-shaped beams at right angles to get a radar "crosshairs" on a target -- and it was simple enough to pick up its signals with a normal SIGINT aircraft. However, the SA-2 was radio-controlled to the target by a ground command link, with the missile carrying a transponder that sent back a signal to the Fan Song radar to allow tracking, and also had a proximity fuze to detonate its warhead when it got close enough to the target. Picking up these 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 instants before the SAM blew the target out of the sky. A special "SAM sniffer" payload was installed to pick up these signals, with the drones relaying the data to an ERB-47 electronics warfare aircraft before they were destroyed. A traveling wave tube (TWT) active radar enhancement device was installed to encourage the enemy to take shots at it.
The three Model 147Ds were delivered in December 1962, but they were never used in their delivery configuration, the mission having changed. They were modified back to Model 147B standard. 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. The White House ordered a study of options, and in May 1964 the study concluded that the Lightning Bug was the best alternative. However, after information about the proposal leaked to the press, the administration decided to back up the U-2s with the Lockheed A-12, the CIA version of the SR-71 Blackbird spyplane.
* The Lightning Bugs remained a potentially valuable reconnaissance asset, and there was no doubt that they would be used. The first opportunity came in August 1964. On 2 August, the destroyer USS MADDOX was sailing in international waters off the North Vietnamese coast when it was supposedly attacked by three North Vietnamese PT boats. The incident, whose details remain murky, led to a major expansion of US involvement in the war in Vietnam. The Johnson Administration feared Chinese intervention in the widening war, and decided to use the Lightning Bugs to monitor Chinese activities. The drones were sent with their DC-130 director aircraft to Kadena Air Force Base on Okinawa to conduct overflights of southern China, under a secret program codenamed BLUE SPRINGS.
The first Lightning Bug mission took place on 20 August 1964. As is not unusual with initial operations of a new system, there were problems. The DC-130 controlling the mission was loaded with a pair of Model 147Bs. One failed to launch, and was later lost when it fell off its underwing pylon. The other successfully completed its mission over China, flew back to Taiwan, deployed its parachute, and splashed down in a rice paddy. However, after splashdown the drone was dragged over the ground by the parachute, badly damaging the machine. The film payload was recovered intact, and although the drone's navigation hadn't been as accurate as hoped, images of several primary targets were recovered.
A total of five Lightning Bug missions was performed over China into early September 1964. Only two were successful; clearly, procedures had to be rethought, and the Air Force conducted a comprehensive review to see what needed to be fixed. There was consideration of killing the BLUE SPRINGS program, but there was some momentum behind it: the Nationalist Chinese were very enthusiastic about the Lightning Bugs, since they had been flying U-2 spyplanes over mainland China on behalf of the CIA, and had been suffering increasing losses from SA-2 SAMs. The Lightning Bugs looked like a better option, if they could be made to fly right.BACK_TO_TOP
* Further Lightning Bug missions were flown in late September 1964. In early October, in order to expand reconnaissance flights to North Vietnam, operations were shifted to Bien Hoa Air Force Base in South Vietnam. The first Lightning Bug mission flown from Bien Hoa took place on 11 October 1964. A rising number of Model 147B missions were flown over North Vietnam and southern China, with a total of 20 reconnaissance drone flights in 1964. The Chinese were extremely eager to shoot the drones down and managed to destroy one on 15 November 1964.
Lightning Bug overflights continued, and so did Chinese efforts to intercept them. The Chinese succeeded in destroying five drones by mid-April, and on 20 April 1965 put the wrecks of three of them on public display. 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 the USAF had considered putting self-destruct charges in the Lightning Bugs, the service finally decided against it. The US government simply adopted a policy of obfuscation when asked about the reconnaissance drones. It worked perfectly. With no American crews lost in the shoot-downs, the US press paid very little attention to the Chinese reports. With the war in Vietnam ramping up, the American public had other things on their minds than little robot airplanes. The secret was kept, though exactly who it was supposed to kept from was another question; the Chinese were of course aware of the Lightning Bugs, and despite the high level of Sino-Soviet frictions at the time, it was likely the Soviets were as well.
* In the meantime, the Air Force had enthusiastically embraced the Lightning Bug and was trying to refine the type, working with Ryan to obtain an improved version of the high-altitude Model 147B, designated the "Model 147G". The Model 147G featured a more powerful J69-T-41A turbojet engine, with 8.5 kN (871 kgp / 1,920 lbf) thrust, replacing the 7.56 kN (770 kgp / 1,700 lbf) thrust J69-T-29A used in its predecessors, and a fuselage stretched to 8.85 meters (29 feet), presumably to provide more fuel for the thirstier engine. The no-con system was also installed. The first Model 147G was delivered to the USAF in July 1965. By this time, the piloted U-2 spyplane had been phased out of flying reconnaissance missions over defended airspace, with that dangerous mission left to the Lightning Bugs.
The drone missions continued, with the Model 147G performing its first mission in October 1965, and the Model 147B flying its last mission that December. However, high-altitude reconnaissance over North Vietnam proved somewhat impractical. During the monsoon season, from November through March, the skies were overcast almost all the time, and even in fair weather smoke or ground haze could obscure reconnaissance targets. For this reason, the Air Force decided to develop a low-altitude version of the Lightning Bug. In October 1965, the service issued a contract to Ryan to develop the "Model 147J", a fast-track modification of the Model 147G with a low-altitude navigation system. Low-altitude flight was more demanding than high-altitude flight, since there were more things to run into, and a number of Model 147J drones were lost in development.BACK_TO_TOP
* Among the 77 missions flown by the drones in 1965 were three flights performed late in the year by a special SIGINT modification of the Model 147B, designated the "Model 147E", another "SAM sniffer" variant. Three Model 147Es were sent to South Vietnam in October 1965 as part of a program codenamed UNITED EFFORT. The SIGINT packages failed on all three initial missions, and the Model 147Es were sent back to the US for environmental tests to track down the problem. It turned out that the SIGINT package failed when overheated; the problem was corrected and the Model 147Es were sent back to the combat zone.
On 13 February 1966, on the fourth mission of the Model 147E, the drone was destroyed by an SA-2, but not before it relayed the vital signal data. The US military had been desperate to get this data ever since the deployment of the SA-2, and officials claimed that this single flight justified the entire Model 147 program. 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".
Another box, the "AN/ALQ-51 Shoe Horn", had been developed to help deal with the Fan Song radar. The AN/ALQ-51 was a "deception jammer", meaning it manipulated radar signals to mislead the radar into thinking the target was someplace other than where it actually was. Since the Americans hadn't actually got their hands on a Fan Song at the time, the box had been tested in the US against a radar simulating a Fan Song. The jammer worked well in tests, but fielding it without sending it up against a real Fan Song was out of the question. A single Model 147B was fitted with the package and redesignated "Model 147F", flying a number of missions in July 1966. It was finally lost after almost a dozen SA-2s had been fired at it.
* Although the virtue of the Lightning Bugs was that they were far more expendable than piloted reconnaissance aircraft, by early 1966 the loss rate was reaching the level where an average of four out of five Lightning Bugs failed to return from missions. It made no sense to expend drones if they didn't return any imagery, and in early 1966 the Air Force asked Ryan to quickly convert ten standard Firebee target drones to expendable decoys. They were fitted with TWT active radar enhancement devices to make them look like bigger aircraft on radar. There were no provisions for recovery or long-range fuel capacity, since their missions were to be one-way only.
The decoys were given the designation of "Model 147N", with the first mission performed by one alongside a Model 147G on 3 March 1966. The two drones followed a parallel path until they reached the target area, where they diverged. North Vietnamese air defenses tracked the "brighter" 147N instead of the 147G, which was recovered. All the Model 147Ns were lost, of course, but as an added bonus they resulted in a few "kills" of North Vietnamese fighter aircraft. One fighter ran out of fuel when the pilot chased the drone out to sea, and other fighters were lost due to "friendly fire" accidents while hunting the drones.
The decoys worked so well that the Air Force ordered another batch of ten, with a few minor improvements, and designated them "Model 147NX". The initial Model 147Ns had been programmed to turn back and head for home in order to simulate a normal operational drone flight profile, and a few of them surprisingly did make it back, even with their limited fuel supply. They crashed, since they were not designed to be recovered, but the recovery system was not expensive and so the Model 147NX was fitted with recovery parachutes and gear, as well as a cheap camera. If the decoy survived the mission, it could provide useful intelligence, as well as be used again.
* By March 1966, the low-altitude Model 147J was ready for operational service. The Model 147J featured a "barometric altitude control system (BLACS)"; a dual camera payload featuring a front-to-back scan camera and a side-to-side scan camera; and a new paint job. The high-altitude Lightning Bugs had been painted black, but since that was a high-visibility color at low altitude, the Model 147Js were painted gray on top and white underneath.
The fast-moving drones streaked low over the ground, making them difficult targets and increasing their odds of returning from a mission. The Air Force also came up with an improved recovery scheme. Up to that time, the drones had parachuted to the ground, but they were often damaged by the landing, and so the USAF came up with a scheme where a big Sikorsky CH-3 "Jolly Green Giant" helicopter snagged the parachute in mid-air and winched up the drone for carriage back to base. Although the scheme sounds tricky, it proved straightforward and effective, with an eventual 2,655 successful recoveries in 2,745 attempts.
A total of 105 drone missions was flown over North Vietnam and China in 1966. Most of these were 147G flights, along with some 147Js, as well as the 147E and 147F SIGINT missions and the 147N and 147NX decoys. One of the 147Js actually took a picture of an SA-2 SAM streaking past it.BACK_TO_TOP
* The USAF was very pleased with the low-altitude Model 147J and feared there would not be enough of them to keep up with operational attrition. Some Model 147Gs were modified to the 147J configuration, but the USAF also asked Ryan to come up with a new low-altitude reconnaissance drone on a fast track. The new variant was the "Model 147NP", which was derived from the initial Model 147A. The Model 147NP had the older J69-T-29A engine and a 4.8 meter (15 foot) wingspan, plus a fuselage stretched to 8.5 meters (28 feet).
While Ryan was working on the Model 147NP, the Air Force also came forward with an urgent requirement for a low-altitude night reconnaissance drone. Four Model 147NPs were pulled from production and modified as "Model 147NREs", where "NRE" stood for "night reconnaissance electronic". The Model 147NREs had a dual-camera payload synchronized to a bright white strobe light fitted into the drone's belly. The strobe lit up the sky when it went off.
Both the 147NREs and the 147NPs went into action in Vietnam at about the same time, in the spring of 1967. The first 147NRE mission was in late May, with the first 147NP mission following a week later. The Model 147NREs were painted black as appropriate to their night mission, while the Model 147NPs were painted in jungle camouflage colors. The Model 147NPs performed as desired, but the Model 147NREs did not quite meet expectations. The "footprint" of the strobe light was fairly small, and the drone's navigation system lacked the accuracy to put the cameras precisely on target. However, 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.
Another low-altitude reconnaissance variant was derived from the Model 147NP, the "Model 147NQ". The main distinction of the Model 147NQ was that instead of an automatic guidance system, it was radio-controlled by a crewman on its DC-130 launch aircraft.
* Despite the Air Force's attention to the low-altitude mission, the service hadn't given up on using Lightning Bugs for high-altitude reconnaissance, and in fact continued to improve the high-altitude variants. The result was the "Model 147H", the third-generation high-altitude Lightning Bug.
The Model 147H had the more powerful J69-T-41A engine of the Model 147G, a lighter airframe, and a wing further stretched to 9.8 meters (32 feet). The wings had internal fuel tanks to increase range. The Model 147H was capable of reaching altitudes of 19.8 kilometers (65,000 feet), and had a new camera payload that provided both greater area coverage and better resolution.
The "stealthy" features that had been originally built into the Lightning Bug had been proving less and less effective, and so the Model 147H was designed with new features to improve survivability, including a radar warning receiver (RWR) to alert the drone if it was illuminated by fighter or SAM radars; an improved guidance system that sent it on a 30-degree right turn when alerted by the RWR; an ECM box named "Rivet Bouncer" to jam the SA-2 Fan Song radar; a coating in the jet intake to reduce radar reflectivity; and an improved no-con system.
The Model 147H was much more highly optimized for its mission than earlier Model 147s, many of which had been modified and put into service as quickly as possible. In contrast, the Model 147H took two years to develop, with the first operational flight in March 1967. Model 147Gs continued high-altitude missions in parallel with the Model 147H drones until the Model 147Gs were phased out in August 1967. Although the 147H drones suffered losses, their survivability did prove better than that of the 147B and 147G.
* While the Model 147H provided a refined solution for the high-altitude mission, the Air Force also pursued a refined solution for the low-altitude mission. Since the low-altitude mission was inherently hazardous, "refinement" meant balancing optimization for the mission against cost.
The initial low-altitude drone, the Model 147J, had been derived from the high-altitude Model 147B and retained the 147B's wide wings. These were a drawback at low altitudes, since they weren't necessary to obtain adequate lift and reduced the drone's maneuverability. The new optimized low-altitude drone, the "Model 147S", had a J69-T-41A engine and featured the original Firebee wings with a 4 meter (13 foot) wingspan. They did the job perfectly well and were cheaper than the long wings. The fuselage was stretched to a length of 8.8 meters (29 feet).
The Model 147S carried a single camera that cost less but provided better coverage than the dual-camera payloads of the earlier low-altitude drones. At typical operating altitudes, the camera system of the 147S could image a strip of land 96 kilometers (60 miles) long, with a resolution of up to 30 centimeters (1 foot), or even 15 centimeters under optimum conditions. Cost of a production Model 147S was about $160,000 USD in contemporary dollars, which was about 60% of the cost of a Model 147G or 147H. The Model 147S drones were built in a number of different production "blocks". The initial 147S block was designated the "Model 147SA", and the subtype performed its initial operational flight in December 1967.
The Air Force was impressed by the results of the Model 147SA missions, and so ordered a second batch of "Model 147SBs". The Model 147SB carried a "multiple altitude control system (MACS)" that allowed it to shift in flight between three preprogrammed altitudes ranging from 300 meters to 6,100 meters (1,000 to 20,000 feet), making it much more unpredictable. It also had improved gyros to permit tighter turns. Initial flights began in March 1968, with the Model 147SAs then being phased out by attrition.
The next block of Model 147S family was the "Model 147SRE", which was intended for the night reconnaissance role. Instead of the white-light strobe used on the Model 147NRE, the 147SRE used an infrared strobe and infrared film. The infrared strobe was barely noticeable from the ground. The 147SRE also featured an improved guidance system, featuring Doppler navigation radar. The first Model 147SRE mission was flown in November 1968. Although the 147SRE performed well, photo interpreters found the infrared images difficult to inspect and sometimes failed to spot targets.
* The low-level 147S flights were "exciting" by the standards of robot warfare. One was misprogrammed before launch and so decided to fly at an altitude of 45 meters (150 feet) instead of 450 meters (1,500 feet) as planned. The drone made it back safely, though photo interpreters were startled to find out that the images included a picture of a power line tower, taken from underneath the power lines. The picture was posted on the unit bulletin board, with a caption provided by the commander: "The FAA [US Federal Aviation Administration] frowns on this bullshit!"
Losses were heavy at the 300 to 450 meter (1,000 to 1,500 foot) altitude set for early Model 147S missions, so the flight altitude was changed to 150 meters (500 feet). The drones were used in missions over Hanoi and Haiphong, which had heavy air defenses. One Model 147S took a picture of an SA-2 streaking past, followed by a picture of the missile exploding, and then due to an autopilot programming error the drone skirted a ridgeline, just missing the treetops.BACK_TO_TOP
* The fourth production variant of the Model 147S family was the "Model 147SC", which featured an improved Doppler radar navigation system with digital controls for greater flight accuracy. Initial operational flight of the Model 147SC, known as the "Buffalo Hunter" by USAF crews, was in January 1969. Of the hundreds of Model 147S drones obtained by the Air Force, most were Model 147SCs, which would eventually fly almost half the total number of Lightning Bug missions.
The US Navy also decided to get into the reconnaissance drone business for a while. They ordered a batch of Model 147SCs modified for ship launch using a RATO booster. The Navy Lightning Bugs were designated "Model 147SK". They were generally similar to the 147SC, except that they had a 4.6 meter (15 foot) wingspan. First operational flight was in November 1969. After RATO launch, a Model 147SK was guided to an initial checkpoint under radio control from a Grumman E-2A Hawkeye airborne early warning aircraft. From that checkpoint, the drone conducted the rest of the flight with its autonomous navigation system, and then was recovered by helicopter. The Navy performed several dozen operational flights, which they referred to as "Belfrey Express" for some obscure reason, with the last flight in May 1970. The Navy did not pursue the Lightning Bug further.
* Despite the fact that most of the Lightning Bug missions were now low-altitude flights, the Air Force still regarded the high-altitude mission as important enough to obtain a refined version of the Model 147H, the "Model 147T". The main improvement was a more powerful engine, the Teledyne / Continental J100-CA-100 with 12.4 kN (1,270 kgp / 2,800 lbf) thrust, that allowed the drone to operate at higher altitudes, up to almost 23 kilometers (75,000 feet). The initial 147T mission was in April 1969, but in practice high-altitude reconnaissance missions continued to decline, with the last Model 147T missions over Southeast Asia performed during June 1971.
However, in April 1969, a Lockheed EC-121 Super Constellation SIGINT aircraft was shot down in international airspace by North Korean fighters, killing all 31 crew members on the aircraft. The incident led to consideration of using an unmanned drone to do the SIGINT job, and the result was the "Model 147TE" or "Combat Dawn" UAV. The first operational flight of the Model 147TE was in February 1970, though this flight and those that followed over two months were really just evaluation tests. The tests proved successful and an order for fifteen production 147TE drones followed, with the first operational flight of a production 147TE in October 1970.
The Model 147TEs did not overfly hostile airspace. They stayed well out to sea at relatively high altitude, or cruised along the border between North and South Korea. They could fly under their own guidance, or be controlled by their DC-130 launch aircraft. The drones relayed SIGINT data over a datalink to ground stations for analysis. This datalink technology would be developed for use in other reconnaissance aircraft, such as the Lockheed U-2 and the Beech RC-12 Guardrail. Late in the Model 147TE program, underwing external tanks were added to improve time on-station from five to eight hours. In 1973, an updated version, the "Model 147TF", with the external tanks as standard and improved SIGINT gear, went into operation. Almost 500 missions were flown by the Models 147TE and 147TF between 1970 and 1975. They were phased out once satellites could perform the mission.
* Back in Southeast Asia, Lightning Bugs continued their overflights. A number of missions focused on a prisoner of war (POW) camp near the city of Son Tay in North Vietnam, in order to determine if US POWs were being kept there. The drone overflights of the Son Tay camp were halted in favor of overflights with the Lockheed SR-71 Blackbird spyplane, since US intelligence officials felt that the drone overflights might make the enemy suspicious. Apparently they did, since when the camp was finally raided on 21 November 1970 there were no American POWs there. It was a disappointing result to one of the more daring operations of the war.
By this time, the Model 147 program was beginning to become public knowledge. AVIATION WEEK magazine carried an article on the drones that November, though it was based on informal and unconfirmed information. The following spring, the Air Force released pictures of the drones along with a very general statement that they were used for reconnaissance. No technical or operational details were released.
The numbers of drone missions continued to increase through 1971 and 1972. The North Vietnamese conducted an all-out invasion South Vietnam in the spring of 1972, which was broken by American air power. US President Richard Nixon then retaliated with an all-out bombing campaign against North Vietnam, codenamed LINEBACKER, to persuade the North Vietnamese to negotiate. The two sides seemed to be close to an agreement, but in December 1972 the talks collapsed, and President Nixon ordered the LINEBACKER II campaign that continued into the final days of 1972. An agreement was reached in January 1973, and the bombing stopped completely.
The Model 147SC was the workhorse for low-altitude reconnaissance during this time. A modified version, the "Model 147SC/TV", was introduced as well in the spring of 1972. This featured a TV camera that relayed imagery to the DC-130 drone controller aircraft.
A variant of the Model 147N, the "Model 147NC", was also flown during this time. It had been designed a few years earlier to fly at medium altitude, carrying a chaff dispenser under each wing to jam enemy radar systems. It had originally been intended to support bombing raids over North Vietnam, but air strikes on North Vietnam were drastically scaled back in 1968 and the Model 147NC was not used in its intended role. When bombing was scaled back up in 1972, chaff was dropped by piloted F-4 Phantom fighters instead. However, during the "political offensive" of that year, Model 147NCs were used to drop propaganda leaflets. The project was codenamed LITTERBUG, but the troops called them "bullshit bombers".
Some sources mention a "Model 147NA", which was apparently an early version of the Model 147NC with a less sophisticated guidance system, and a low-level version designated the "Model 147NC(M1)".
The Model 147H was on the way out by this time, performing its last mission in September 1972. The Soviets had updated the SA-2's electronics, and so American electronic countermeasures needed to be updated as well. Cameras were replaced by a "SAM sniffer" payload, and a Model 147H flight on 28 September was able to obtain the necessary data before the drone was destroyed by an SA-2.
* Reconnaissance flights continued after the signing of the peace treaty, in order to ensure that the North Vietnamese were honoring their side of the bargain. New drone variants were introduced as well. The "Model 147SD" featured external underwing tanks; a substantially more accurate navigation system; and a new cooling system to deal with tropical environmental conditions. The "Model 147SDL" featured a navigation system that obtained position information from the LORAN radio location network, providing the drone with greater accuracy.
By this time, drone technology and operational practice had been refined. While the Model 147SC drones had been designed to survive an average of 2.5 missions, in practice the average was much higher. One, named "Tom Cat", performed a record 68 missions.
The Lightning Bug program had proven highly successful. A series of fast-track adaptations of an existing target drone resulted in an system whose effectiveness was beyond expectations, even with guidance technology that was extremely crude by modern standards. However, the Lightning Bugs could not affect the course of the war. In the end, their reconnaissance clearly showed that the North Vietnamese were violating their agreement with the Americans on a massive scale, but the US wanted no more of an endless war. Americans had no more stomach for losing more of their sons to an enemy who was willing to lose theirs in large numbers, and when the final North Vietnamese push jumped off in early 1975, the US did little to stop it. Saigon fell on 30 April 1975, and the war was effectively over.
Despite its effectiveness, so was the Lightning Bug program. The last Model 147S drone flight was on the day Saigon fell. The Model 147TF flights continued until June 1975, and then most of the surviving drones were stockpiled.BACK_TO_TOP
* A total of 3,435 Lightning Bug missions was flown against Communist China, North Vietnam, and North Korea, with the mission breakdown by year as follows:
1964: 20 1965: 77 1966: 105 1967: > 100? 1968: 340 1969: 437 1970: > 400? 1971: 406 1972: 570 1973: 444 1974: 518 (includes flights in first half of 1975)
Almost half of the missions were flown by the Model 147SC, of which about a thousand were built. 578 drones of all types were lost, with over half shot down and the rest lost in various accidents. It is something of a compliment to the usefulness of the Model 147 that the Chinese used the Lightning Bugs shot down over their territory to copy the basic Firebee design and produce it themselves as the "WZ-5", which was introduced into service in the early 1980s.
_________________________________________________________________________ SUMMARY TABLE OF MODEL 147 DRONES: _________________________________________________________________________ 147A Initial variant, minor mod of Firebee with stretched fuselage. 147C 147A update, no-contrail system, 4.6 meter (15 foot) wingspan. 147D Modified 147C to "sniff" SAM proximity fuze emissions. 147B First high-altitude variant, 8.2 meter (27 foot) wingspan. 147G 147B update, fuselage stretch, no-contrail system, new engine. 147H Optimized high-altitude drone, 9.8 meter (32 foot) wingspan. 147T Improved 147H with more powerful engine. 147E 147B with 147C SAM "sniffer" payload. 147F One-off 147B mod to test SA-2 countermeasures. 147J Fast-track mod of 147B for low-altitude reconnaissance. 147TE ELINT version of 147T, used in Korea. 147TF Improved 147TE with external tanks. 147N Expendable decoy derived directly from Firebee. 147NA Chaff dispenser variant. 147NC Chaff / leaflet dispenser variant. 147NC(M1) Low-level version of 147NC. 147NX Expendable decoy with secondary reconnaissance capability. 147NP Fast-track low-altitude drone derived from 147A. 147NRE Night reconnaissance modification of 147NP. 147NQ Radio-controlled version of 147NP. 147SA Optimized low-altitude 147, Firebee wings, stretched fuselage. 147SB 147S variant with multiple-altitude control system. 147SRE Night reconnaissance 147S with infrared strobe, Doppler radar. 147SC Improved Doppler navigation system, largest number produced. 147SC/TV 147SC with TV camera. 147SK Naval 147SC with 4.6 meter (15 foot) wingspan and RATO launch. 147SD 147SC with improved navigational system, external tanks. 147SDL 147SD with LORAN guidance backup. _________________________________________________________________________
The Model 147s were referred to by the Air Force in general under the designation "AQM-134". This designation scheme wasn't created until 1969 and only applied to those Model 147s still in service at the time. The designations include:
_________________________________________ 147H: AQM-34N 147NA/NC: AQM-34G (chaff dispensing) 147NC: AQM-34H (leaflet dispensing) 147NC(M1): AQM-34J 147SC: AQM-34L 147SD: AQM-34M 147SRE: AQM-34K 147T: AQM-34P 147TE: AQM-34Q 147TF: AQM-34R _________________________________________
A handful of Model 147SC / AQM-34L drones were fitted with upgraded avionics in 1972 and redesignated "YAQM-34U", and would become "BGM-34C" multipurpose drones, described later.
In the early 1970s, the airframe of one Model 147G was reinforced by the Air Force Flight Dynamics Laboratory (FDL) to investigate high maneuverability flight. The modified drone was originally designated the "FDL-23" and later the "XQM-103". A few test flights were performed, with the machine able to perform ten-gee turns in its final configuration.
In the late 1970s, a number of 147NC AQM-34H/AQM-34J drones were converted to an improved countermeasures specification, with chaff dispensers as well as active jamming gear, and redesignated "Model 255 / AQM-34V". First flight was in 1976. About 44 were converted, to be joined by about 16 new-build machines. They joined the other Lightning Bugs in storage in 1979.
A number of reconnaissance Firebees were delivered to the Israelis in the early 1970s. These UAVs were fitted to Israeli specifications for low-altitude observation, and were designated "Model 124I". The Israelis called them "Mabat", meaning "observation". They were ground-launched with a RATO booster and recovered in mid-air by helicopter, saw service in the 1973 Yom Kippur war and later conflicts, and were not retired until the mid-1990s.
* In the late 1990s, Teledyne-Ryan configured two Firebees using company funds with cameras and communications electronics to provide real-time intelligence for battlefield target acquisition and damage assessment. These two UAVs, which were named "Argus", were used in a USAF "Green Flag" exercise to relay images in real-time from the test range in Nevada to USAF officers in Florida.
Five BQM-34-53 Extended Range Firebees were also used to lay chaff corridors during the American intervention in Iraq in the spring of 2003. The drones were modernized by Northrop Grumman in a fast-response program earlier in the year, being fitted with chaff dispensers and other improvements. They had GPS-based programmable waypoint guidance systems, but it is unclear if they were added by the upgrade program. They were delivered for service in charcoal-black colors.
There was only one DC-130 drone launcher aircraft left in the US military's inventory at the time, and since it was grounded due to a malfunction, two Firebees were ground-launched on the first night of the operation. The other three were air-launched by the DC-130 on the second night of the operation. They flew until they ran out of fuel and crashed. Iraqi TV took footage of the wrecks and broadcast it, saying they were wrecks of piloted aircraft.
The last Firebee was delivered in 2002, but Northrop Grumman is implementing upgrades for existing machines, such as GPS programmable waypoint navigation systems and satellite links. Given the maturity and low cost of the Firebee, it would not be surprising if it remained in service much longer, at least for simpler missions.BACK_TO_TOP