[2.0] The General Atomics Predator & Reaper

v1.0.0 / chapter 2 of 3 / 01 dec 17 / greg goebel

* After a slow emergence, endurance drones are now an important military asset. This chapter covers the well-known General Atomics Predator / Reaper series of endurance drones.

General Atomics Reaper



* Modern US government studies for endurance drones, powered by more or less conventional turbocharged aircraft engines, began with a secret study begun by DARPA in the early 1980s, codenamed TEAL RAIN. Following the study, in 1984 DARPA awarded a $40 million US contract to Leading Systems Incorporated (LSI) of Irvine, California, to build an endurance drone named "Amber". Amber was to be used for photographic reconnaissance, ELINT missions, or as a cruise missile. The US Army, Navy, and Marine Corps were interested, and DARPA eventually passed control over to the Navy. The Navy saw it as a potentially useful system for over-the-horizon support of fleet strike forces.

Amber was designed by a team under Abraham Karem of Leading Systems. Amber was 4.6 meters (15 feet) long, had a wingspan of 8.54 meters (28 feet), weighed 335 kilograms (740 pounds), and was powered by a company-built four-cylinder liquid-cooled piston engine providing 49 kW (65 HP), driving a pusher propeller in the tail. The wing was mounted on a short pylon above the fuselage. The cruise missile version of Amber would discard the wing when it made its final dive on a target. Amber had an inverted-vee tail, which would prove a popular configuration for a pusher drone, since it protected the propeller during takeoff and landing. The airframe was made of plastic and composite materials, mostly Kevlar, and the drone had retractable stiltlike tricycle landing gear to ensure propeller clearance. Amber had a flight endurance of 38 hours or more.

The initial contract specified three "Basic Amber" A-45 cruise missile prototypes and three B-45 reconnaissance prototypes. Initial flights were in November 1986, with long-endurance flights the next year. Amber had been a classified program up to then, but in 1987 details of the effort were released.

Amber was only one of a number of different US drone programs in planning at the time; the US Congress became impatient with what was perceived as confusion and duplication of effort. Congress ordered a consolidation of drone programs in 1987, freezing funding until June 1988, when the Pentagon established a centralized "Joint Program Office" for drone development.

Amber survived the consolidation of drone efforts into JPO, resulting in the first "Amber I" reconnaissance drone, which first flew in October 1989. Seven Amber Is were built, and were used in evaluations along with Basic Ambers through 1990. However, funding for reconnaissance assets was being cut, and in 1990 the Amber program was killed. It didn't have strong backing, and it said that Karem, though brilliant, had a blunt and abrasive personality that didn't help his cause. LSI was faced with bankruptcy, and was bought out by General Atomics -- a firm originally focused on nuclear technology, which then diversified into several other directions.

* Amber died, to be quickly resurrected. In 1988, LSI had begun development of a simplified version of the Amber named the "Gnat 750", intended for foreign sales. The Gnat 750 made its first flight in 1989. Its configuration was similar to that of the Amber, except that the Gnat 750's wing was mounted low on the fuselage, instead of being mounted on a pylon on top. The Gnat 750 was somewhat larger than the Amber, but weighed less and could carry a heavier payload.

The Gnat 750 was powered by a Rotax 912 piston flat-four four-cycle engine with 64 kW (85 HP). The drone could fly to an operational area 2,000 kilometers (1,240 miles) away and loiter there for 12 hours before returning home.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                10.75 meters        35 feet 4 inches
   length                  5 meters            16 feet 5 inches
   height                  0.75 meters         2 feet 5 inches

   empty weight            250 kilograms       560 pounds
   max loaded weight       520 kilograms       1,140 pounds

   maximum speed           212 KPH             132 MPH / 115 KT
   service ceiling         7,620 meters        25,000 feet
   endurance               48 hours
   _____________________   _________________   _______________________

* Eight Gnat 750s were in development when General Atomics bought out LSI. General Atomics continued the program, which led to a contract from the Turkish government for a number of the drones in 1993.

By that time, the disintegration of the old Communist states of Eastern Europe was in full swing, and the US government wanted to obtain an intelligence asset to help deal with trouble spots in the region, specifically the former Yugoslavia. A contract was issued to General Atomics for Gnat 750s with minor modifications. The Gnat 750s were to be operated by the CIA. The program encountered a number of difficulties, much of them due to bureaucratic factionalism and squabbling. One Gnat 750 crashed during tests when it was hit by a gust of wind from the rear, causing it to indicate zero airspeed. The drone's software decided that meant it had landed and shut down the engine; the Gnat promptly fell to earth.

Despite such problems, the Gnat 750 effort squeaked through, and in early 1994 the CIA sent a team equipped with a Gnat 750 to Albania to monitor events in the former Yugoslavia. Although the results of the operation were regarded as positive, it also showed some of the difficulties involved in drone operation. The Gnat 750 suffered from a number of bugs and was limited by bad weather as well as "terrain that defies description", as one participant put it.

The original Gnat 750 was followed by an "Improved Gnat" or "I-Gnat" variant, with a turbocharged engine and general overall refinements to increase reliability, reduce maintenance, and enhance capability. The Gnat is apparently out of service, having been replaced by improved derivatives, as per below.

* NASA obtained a derivative of the Gnat 750 named the "Altus" for high-altitude research. The Altus and looked much like the Gnat 750 but had a different fuselage and a longer wingspan. The Altus was 7.2 meters (23 feet 7 inches) long, had a wingspan of 16.9 meters (55 feet 4 inches), and a takeoff weight of 725 kilograms (1,600 pounds). It could carry 150 kilograms (330 pounds) to 13.7 kilometers (45,000 feet) with an endurance of 24 hours. The engine was originally a Rotax 912 flat-four piston engine with a single stage of turbocharging.

Altus II

An Altus spent 26 hours above 6,100 meters (20,000 feet) in 1996, and spent four hours above 16,800 feet (55,000 feet) in 1999 after being fitted with a two-stage turbocharger system, updating it to the Altus II configuration.

General Atomics also used the Gnat 750 as the basis for a tactical drone, known as the "Prowler". It looked much like a Gnat 750, but was cut down in size, with a span of 7.31 meters (24 feet) and a length of 4.24 meters (13.9 feet). It had an endurance of over 16 hours, and some commonality with Gnat 750 subsystems. Nobody bought it, and it was abandoned.



* The Gnat 750 was effectively an interim design, leading to much more definitive General Atomics "RQ-1 Predator", which is now in widespread service. The RQ-1 Predator resembles the Gnat 750 in general configuration, with some clear differences, most significantly the fact that the Predator is much bigger, with about twice the empty weight. While the Gnat 750's fuselage was straight and streamlined, the Predator's fuselage looks something like a plastic spoon turned upside down and faired over underneath, with the bulbous front containing a forward-looking SAR peering out through a chin panel, and sensor turret under the nose. Initially the sensor turret had only an EO/IR imager system; later a laser target designator was added. There is a hardpoint for a stores pylon under each wing.

The Predator is fitted with a number of datalink antennas, for control or data download via a direct RF or satellite link. The drone can provide real-time data to other platforms, such as the J-STARS battlefield surveillance aircraft, or submarines. The Predator takes off and lands under remote control, with the "pilot" using a TV camera in the nose of the aircraft, but flies in a preprogrammed pattern, using a GPS-INS guidance system. Like the Gnat-750, it is built largely of composites and powered by a Rotax 912 piston engine, and has a payload capacity of 225 kilograms (500 pounds).

The initial Predator system was designated "RQ-1A", but that designation covered the entire system, which had the more specific designation of "RQ-1K". The distinction was confusing and the Air Force finally abandoned it, calling the drone itself the "RQ-1A".

The Predator is designed to keep watch over a battlefield area for a long period of time. If a Predator were flown out of San Francisco, it would be able to operate into Nevada, southern Oregon, or northwestern Mexico and monitor a 185 x 185 kilometer (115 x 115 mile) grid. The Predator is almost completely silent, and is invisible to the eye at ranges of about 4 kilometers (2.5 miles) or more.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                14.8 meters         48 feet 8 inches
   wing area               22.5 sq_meters      123 sq_feet
   length                  8.22 meters         27 feet
   height                  2.1 meters          6 feet 11 inches

   empty weight            512 kilograms       1,130 pounds
   max loaded weight       1,020 kilograms     2,250 pounds

   maximum speed           215 KPH             135 MPH / 115 KT
   service ceiling         7,620 meters        25,000 feet
   endurance               24 hours
   _____________________   _________________   _______________________

* The Predator was developed by the JPO. The first Predator flew in mid-1994, with the type evaluated by the US Air Force in exercises over New Mexico in the spring of 1995. Three Predators were deployed over Bosnia that summer, flying out of Albania, with one command-destroyed after an engine failure and another apparently shot down. These aircraft were replaced. Initially, these Predators only had the EO/IR turret payload, but they were withdrawn to the US for fitting the SAR payload, and then returned in the spring of 1996. The Predator was passed over to Air Force control after its Bosnian service. The Air Force promptly put the Predator into service in the air campaign against Yugoslavia in 1999.

The Predator's service in the Kosovo campaign left something to be desired, since it was unarmed and operators of the drone were not properly trained or equipped to direct strike aircraft pilots onto a target. The result was a comedy of errors, with one officer involved saying that with such clumsy methods it would 45 minutes to get a strike aircraft into the same zip code. That drove fit of a new turret with a laser target designator, but that improvement was too late for the Balkans, not being initially fielded until 2001.

The US Navy operated two Predators on an experimental basis. General Atomics partnered with Alenia of Italy's Meteor subsidiary for a successful bid on an Italian Army endurance drone requirement. Six Predators were ordered, with the drone going into service with the Italian Army at the end of 2004. Italian Predators were sent to Iraq in 2005 to help assist Italian occupation forces in that country.

In 2013, the United Arab Emirates ordered a batch of "Predator XP" drones, which used the RQ-1 airframe but had an improved engine and new avionics -- including a maritime search radar, to permit them to perform Persian Gulf patrols.

The Air Force is now phasing out the Predator, with the type to be fully withdrawn from service in 2018. It is likely many will be passed onto civil users.



* The limitations of the Predator in the Kosovo campaign also drove carriage of Hellfire anti-armor missiles, the rationale being that the Predator might need to engage a target itself if a strike platform couldn't get there soon enough. Trials with Hellfire were conducted in early 2001, with one Hellfire on the pylon on each wing, and proved successful. The effectiveness of the scheme was a relief, because nobody was quite sure that firing a Hellfire from a Predator wouldn't rip the drone's wing off. The configuration was put into service, with the armed Predators given the new designation of "MQ-1A".

MQ-1 Predator with Hellfires

Given that a Predator is very unobtrusive and the Hellfire is supersonic, such a combination gives little warning of attack. An improved "Hellfire P" variant of the missile was fielded, featuring an "off boresight" seeker that can be gimbaled to get a target lock, eliminating the need to point the Predator at a target. This permits faster targeting and a wider missile launch envelope. The Air Force has also considered other small munitions for carriage by the Predator.

There were concerns over arming the Predator, since it could then be regarded as a "cruise missile" and so would be subject to arms limitation treaties, but the utility of the Predator as a strike platform was very attractive, and the demand was there. After attacks on America on 11 September 2001 by terrorists associated with Saudi dissident Osama bin Laden and his Afghanistan-based al-Qaeda terrorist network, in early October of that year the US military began a campaign against Afghanistan intended to root out Osama and the al-Qaeda.

The Predator was a particularly important element in the campaign, being used by the USAF to locate high-priority targets for air strikes. The Predators were armed with Hellfires to ensure that if Osama or other al-Qaeda leadership were spotted, they could be attacked immediately. On 18 November 2001, a Predator was supporting an attack on a Taliban site when the drone's operators spotting enemy forces fleeing the site. A Hellfire was launched, killing dozens, including some Taliban leadership.

On 3 November 2002, an MQ-1L operating over Yemen spotted a car that was identified as carrying a high al-Qaeda official and five of his people. The Predator blasted the car with a Hellfire, killing all the occupants. The drone was operated by the CIA, but was being flown by a USAF pilot from a French military base in Djibouti, in the horn of Africa. The attack was cued by observers on the ground.

The Stinger AAM was qualified as a store as well, though the military kept quiet about it. However, a Predator has used a Stinger in combat. On 23 December 2002, a Predator got into a "shoot-out" with an Iraqi MiG-25, firing a Stinger at it, while the MiG-25 fired an AAM back. It was the first time in history a drone engaged in air-to-air combat, but it was not an inspiring introduction: the Predator lost the shoot-out and was destroyed.

Of course, Predators were employed in the American invasion of Iraq in the spring of 2003. One fired a Hellfire at an antenna on the roof of the Iraqi propaganda ministry in Baghdad to get the propaganda minister, Mohammed Saeed al-Sahaf, off the air. The propaganda minister had acquired an international reputation for his colorful remarks, and was known as "Baghdad Bob" to American forces, but the decision was taken to finally shut him up. The Predator-Hellfire was used because the propaganda ministry was close to the grand mosque, and nobody wanted to risk damaging it by using a larger munition.

Interestingly, some of the older Predators and Gnat-750s, as well as old Pioneer and Hunter drones, were stripped down to be used as decoys to provoke Iraqi defenses. After the occupation of Iraq, CIA-operated Predators and I-Gnats were launched from both Afghanistan and Iraq to probe Iran for evidence of a nuclear program, with one apparently lost in a crash in Iran in the summer of 2005. Predators are continuing to be aggressively used in the Middle East, South Asia, and Africa, fueling an ongoing controversy over their use as a tool in "stealth warfare", conducted off the radar of public attention.

In any case, USAF Predators are actually "piloted" from Nellis AFB and Creech AFB in Nevada. Only a relatively small service and handling team deals with the machines "in theater". One pilot flying the Predator from Nellis who had been on the battle lines says the experience is much the same: "Physically, we may be in Vegas [Nellis AFB is next door to Las Vegas], but mentally we're flying over Iraq. It feels real."

The Air Force had been hard-pressed to train personnel to fly the Predators, and the pilots have been badly overloaded, making retention troublesome. A "multiple aircraft" control system is being introduced, allowing one pilot to control up to four Predators, with three machines operating on autopiloted search patterns while one is under direct control. The Predators are so heavily tasked that there weren't enough to go around for stateside training exercises, and so in 2009 the Air Force kitted up two Cessna 182 light civil aircraft with Predator EO/IR turrets to act as training surrogates for Predators. The two aircraft were operated by Civil Air Patrol volunteers under USAF supervision.

The Air Force has also had a troublesome learning curve with the Predator itself, with a good number of them lost in accidents. Problems included and loss of datalink connection from interference, and icing up in cold weather -- the Predator doesn't have a high enough ceiling to fly over the weather. Later production Predators obtained by the USAF were fitted with de-icing systems, along with an uprated turbocharged engine, improved avionics, and a wing stretch to 16.84 meters (55 feet 4 inches). This improved "Block 1" version is referred to as the "RQ-1L", or the "MQ-1L" if it can carry munitions. Predators have also been given improved avionics, including new sensors and a SIGINT system.



* With the Predator proving so useful, in the summer of 2005 the US Army, having initiated an "Extended Range / Multi-Purpose (ER/MP)" drone requirement a year earlier, formally decided to jump on board the bandwagon by awarding a contract to General Atomics for the "MQ-1C Gray Eagle" -- originally "Sky Warrior" -- a Predator with a heavy fuel (diesel / jet fuel) engine, a slightly increased wingspan, and increased system redundancy. The Army had already operated I-Gnats in small numbers from 2003.

The MQ-1C can carry surveillance, communications relay, signals intelligence, electronic warfare, and strike payloads. The Thielert heavy-fuel engine is said to provide more horsepower (120 kW / 160 HP), better fuel efficiency, and greater reliability than the Rotax 912 gasoline engine, though apparently the major driving force for adopting the new engine was the fact that Army vehicles are diesels, and having to support a gasoline engine in the field would have been logistically troublesome. The Gray Eagle features a tactical datalink along with its satellite comlink, and can carry a warload of four Hellfire missiles, twice that of the original Predator, total external load being 180 kilograms (400 pounds). Operational endurance is up to 25 hours.

General Atomics MQ-1C Gray Eagle

First flight was in the spring of 2008, with the initial "Block 0" MQ-1C in service in Iraq a month later for combat evaluation, being followed by improved blocks. The latest variant, the "Improved Gray Eagle (IGE)", first flew in 2013 and went into service in 2017. The IGE features:

In service, Gray Eagles have received avionics updates, notably to improve datalinking with other platforms. There has also been considerable work to improve reliability, which was poor at the outset.

Although the relationship between the Air Force and the Army over the close-support mission has been generally, if not always, good, Army brass also like to have their own air support assets. Something of a "turf battle" has taken place between the Army and the Air Force over the Predator, with the Air Force attempting to take over control of relatively capable drone assets such as the MQ-1C from the Army. To no surprise, the Army strongly resisted the idea.



* Given the limitations of the original Predator, to no surprise General Atomics came up with an improved "Predator B" series. Development began with the "Predator B-001", a proof-of concept aircraft, which performed its initial flight on 2 February 2001. The B-001 was powered by a Honeywell / Allied-Signal TPE-331-10T turboprop engine providing 712 kW (950 SHP). The Predator B-001 had a standard Predator airframe, except that the wings were stretched from 14.6 meters (48 feet) to 19.5 meters (64 feet).

Although General Atomics originally considered a Predator B variant powered by a turbofan engine, there was more interest in the turboprop configuration at the time, and the production machines retain the TP-331-10T engine. The production machines have a maximum ceiling of 15.8 kilometers (52,000 feet), and an endurance of 36 hours. The higher ceiling allows the Predator B to fly above bad weather conditions. The turboprop engine is not only more powerful than the Rotax piston engine, it also has a much longer mean time between failures. The ground system remains much the same as that of the original RQ-1 / MQ-1 Predator. Cost is several million dollars more than that of a Predator A, but still a fraction of the cost of a piloted combat aircraft.

General Atomics had originally funded Predator B development with company money in anticipation of government interest and contracts, and the bet paid off. In October 2001, the US Air Force signed a contract with the company to purchase an initial pair of Predator Bs for evaluation. The Air Force then ran a competition in 2004 for a "Hunter-Killer" drone; the Air Force had an immediate need, the Predator B was pretty obviously what USAF brass had in mind and it was effectively available, so the Predator B handily won the award -- indeed, the competition had the feel of being no more than a formality.

The USAF designated the type the "MQ-9B Hunter-Killer" or "Reaper". Reapers were quickly fielded, performing combat evaluations in Afghanistan in late 2007. Several hundred of the drones have been obtained to date, with the Air Force intending to bring the fleet to 327 machines.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                20 meters           66 feet
   length                  11 meters           36 feet
   height                  3.6 meters          12 feet 6 inches

   empty weight            2,225 kilograms     4,900 pounds
   max loaded weight       4,760 kilograms     10,500 pounds

   maximum speed           260 KPH             300 MPH / 260 KT
   service ceiling         15,000 meters       50,000 feet
   endurance               24 hours
   _____________________   _________________   _______________________

The MQ-9B is fitted with six stores pylons, with a respectable maximum external load of 1,360 kilograms (3,000 pounds). The inner stores pylons can carry a maximum of 680 kilograms (1,500 pounds) each, and are "wet" to allow carriage of external fuel tanks. The midwing stores pylons can carry a maximum of 270 kilograms (600 pounds) each, while the outer stores pylons can carry a maximum of 90 kilograms (200 pounds) each. An MQ-9B with two 450-kilogram (1,000-pound) external fuel tanks and 450 kilograms of munitions has an endurance of 42 hours. Avionics, particularly the targeting system, were improved relative to the Predator A -- though the same ground systems can be used with both drones.

MQ-9B Reaper

The Reaper gives the Air Force an enhanced "deadly persistence" capability, with the drone hanging over a combat area night and day, waiting for a target to present itself. In this role, an armed drone neatly complements piloted strike aircraft. A piloted strike aircraft can be used to dump larger quantities of ordnance on a known target, while a cheaper drone can be kept in operation almost continuously, with ground controllers trading off in shifts, the drone carrying a light warload to engage targets of opportunity.

The Hellfire available at the time wasn't qualified for operation at cold temperatures found at high altitudes, nor does it have the range to hit targets from such altitudes. It is likely that the Reaper will carry the Joint Air-to-Ground Missile (JAGM), the follow-on to Hellfire, when JAGM enters service. Other munitions carried by the Reaper include the the 112-kilogram (250-pound) Small Diameter Bomb (SDB), or even the 225-kilogram (500-pound) version of the Joint Direct Attack Munition (JDAM) GPS-guided bomb for larger targets. New small smart bombs now entering service are also candidate Reaper stores.

Along with carriage of the Stinger AAM, there has been some thought of carriage of the bigger Sidewinder, or even the long-range AIM-120 AMRAAM, as stores. The AMRAAM would require that the Reaper carry an improved radar with AMRAAM targeting and control capabilities. General Atomics has published ads showing the Reaper armed with twin 225-kilogram guided bombs, eight Hellfires, and two Sidewinders, demonstrating just how powerful a punch the machine can pack.

The Reaper was, as noted, primarily obtained for the armed persistence role, but of course it can perform surveillance as well. It can carry optical / infrared or synthetic aperture radar (SAR) reconnaissance pods, and was used for the development of the the "Gorgon Stare" pod, which includes a dozen video cameras and can maintain a constant view of a city-sized area, relaying multiple scenes from the target area to multiple users simultaneously. In addition, the Reaper has been evaluated with electronic warfare payloads.

A "Block 5" Reaper was introduced to service in 2017, this version featuring greater MTO for more fuel and payload, with the landing gear revised to handle the increase in weight; a heftier starter-generator to provide more electrical power; improved avionics; and a refined payload integration scheme.

Along with the standard Predator, the Air Force also obtained a "Reaper ER", which is like the Block 5, with the stronger landing gear, but can carry an external tank under each wing, giving it a maximum endurance of 42 hours. It also has a water-methanol injection engine system to boost takeoff power, and a four-bladed prop. Introduction to service was in 2015, with the Air Force obtaining at least 38 to date. General Atomics has pushed a new wing design, with span extended to 26.8 meters (88 feet), winglets on the wingtips, and wing internal fuel tanks to eliminate the need for external tanks.

* There have been a number of foreign sales of the MQ-9B:

In addition, several US government civilian agencies fly or have flown the Reaper, The US Forest Service (USFS) evaluated a Reaper in a collaborative program with NASA and the US Federal Aviation Administration (FAA). The USFS and NASA conducted some trials in 2006 with a leased Predator B, leading to operations in 2007 with a Reaper obtained from the USAF.

This machine was renamed "Ikhana", from the Choctaw word for "intelligent" or "aware"; the name "Reaper" seemed a bit too warlike for a civil application. The Ikhana carried a NASA-designed infrared sensor package for fire mapping: although a standard Reaper can carry an infrared imager as a normal payload, it's too sensitive to be used to observe big, hot fires. The sensor package relayed imagery back to a ground station in real-time to allow warnings to be sent to fire-fighters.

Ikhana drone

NASA not surprisingly is also considering a range of other missions for the Ikhana. The US National Oceanographic & Atmospheric Administration (NOAA) is planning collaborative drone efforts with NASA for weather and climate research. The two agencies have long collaborated on weather satellites and drones would only be an extension of existing practice.

The US Department of Homeland Security (DHS) is another user of the Predator B, with about half a dozen in service for border patrol and disaster response. In 2010, the DHS's Customs & Border Protection (CBP) organization evaluated a Predator B for hunting drug smugglers, with the machine fitted with a belly fairing for a Raytheon AN/APS-134 SeaVue radar, plus wingtip aerials for UHF/VHF radio links, with this variant known as the "Guardian".

The US Missile Defense Agency (MDA) has been experimenting since 2009 with a set of Reapers fitted with an "Airborne Infrared (ABIR)" system to track missile launched for targeting by anti-missile defense systems. There's no commitment to deployment, but the MDA is considering the matter.

General Atomics designed a navalized version of the Reaper, named the "Mariner", for carrier operations, and flew a demonstrator, the primary motivation being the US Navy "Broad Area Maritime Surveillance (BAMS)" program. The production Mariner would be turboprop-powered, with folding wings for carrier storage; shorter and more rugged landing gear; an arresting hook; cut-down or eliminated ventral flight surfaces; and six stores pylons with a total load of 1,360 kilograms (3,000 pounds).

The BAMS award was won by the Northrop Grumman RQ-4N, as discussed later. However, General Atomics is still pushing the Mariner, envisioning it as carrying a pod under each wing for active and passive sonar buoys, allowing it to spot and track submarines.



* Although General Atomics did backtrack on development of a turbofan-powered Predator variant, the idea didn't die out. The company kept quiet about the effort -- but in the spring of 2009 announced that a "Predator C" or "Avenger" prototype had performed its first flight on 4 April 2009. It was followed by a second prototype in 2012, closer to intended production spec, with a 1.2-meter (4-foot) fuselage stretch and a loaded weight about 10% bigger.

The Avenger clearly looks like a member of the Predator family, but it also was clearly designed for stealth. It has relatively smooth contours, with the engine -- a Pratt & Whitney Canada (PWC) PW545B turbofan with 21.3 kN (2,175 kgp / 4,800 lbf) thrust -- carried on the back and using a wide exhaust, hidden behind an upright vee tail with "all moving" tail surfaces. It also has retractable tricycle landing gear -- all with single wheels, the nose gear retracting backwards, the main gear hinging in from the wings towards the fuselage -- and even a weapons bay to permit stealthy carriage of stores. Additional fuel tanks can be stored in the weapons bay, and a conformal sensor pack can be plugged into it. External stores can be carried when stealth is not required. Total internal payload is given as 1,350 kilograms (3,000 pounds), with an equivalent external payload capacity.

Avenger C drone

The Avenger has a length of 13.4 meters (44 feet) and a wingspan of 20.1 meters (66 feet). The wings have a sweep of 17 degrees; they can be folded for compact storage. Fuel carriage is split between the fuselage and inner wing sections. Endurance is cited as up to 20 hours, top speed in excess of 740 KPH (460 MPH / 400 KT), and maximum altitude as 18,300 meters (60,000 feet). A total of at least four prototypes were built -- one machine being modified to an "Avenger ER" configuration, with a wing stretch of 3 meters (10 feet), to

General Atomics developed the Avenger on company funds, with an eye towards sales to the US military. The Air Force obtained the first prototype in 2011 for evaluation, but decided not to procure the type, finding the MQ-9 Reaper satisfactory to needs. In 2010, General Atomics announced a "Sea Avenger" for carrier-based use, featuring navalizations such as catapult attachment and arresting hook. However, US Navy interest proved stillborn as well. General Atomics is now pitching the Avenger on the international market.