v1.4.1 / chapter 14 of 19 / 01 mar 08 / greg goebel / public domain
* Endurance UAVs are now being built around the world. This chapter provides a short review.
* IAI has developed an endurance UAV version of the Hunter, known as the "E-Hunter", with extended wings. Apparently it is provided as a kit that can be retrofitted to a standard Hunter.
IAI MALAT E-HUNTER:
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spec metric english
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wingspan 15.2 meters 50 feet
length 7.53 meters 24 feet 8 inches
max loaded weight 950 kilograms 2,100 pounds
maximum speed 195 KPH 120 MPH / 105 KT
service ceiling 6,100 meters 20,000 feet
endurance 25 hours
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IAI Malat has developed a larger endurance UAV named the "Heron", which uses
the typical twin-boom pusher prop configuration favored by the company, but
on a larger scale. It has some resemblance to the E-Hunter in terms of its
wing and tail layout, but the fuselage is different, with a single pusher
engine. It first flew in 1994. The Heron is powered by a turbocharged Rotax
914 engine, includes system redundancy for reliability, and has retractable
tricycle landing gear plus an arresting hook.
IAI HERON:
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spec metric english
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wingspan 16.6 meters 54 feet 6 inches
length 8.5 meters 27 feet 11 inches
payload weight 200 kilograms 440 pounds
max loaded weight 1,100 kilograms 2,420 pounds
maximum speed 230 KPH 145 MPH / 125 KT
service ceiling 10,700 meters 35,000 feet
endurance 50 hours
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India has ordered six to eight Herons, and in the spring of 2005, the Turkish
military ordered the Heron from IAI, with the order including ten ground
stations with three or four UAVs each.
The Heron has been tested with a SAR for maritime surveillance, with the antenna stored in a large belly fairing. IAI has flown a turboprop version of the Heron, the "Heron-TP" AKA "Eitan", with a 750 kW (1,000 HP) turboprop engine, able to carry a 590 kilogram (1,300 pound) payload at an altitude of 12,800 meters (42,000 feet), a cruise speed of 445 KPH (240 KT), and an endurance of 20 hours.
It has led to the mostly-secret "Heron II" operational machine, which is about a third heavier than the original Heron and is said to be intended for reconnaissance, surveillance, air defense, attack, and tanker roles. IAI Malat has also considered a "Heron-TJ", with twin Williams FJ44-2 turbofans.
* The Israeli Silver Arrow company has developed a long-endurance UAV named the "Hermes 450". This UAV is powered by twin 27 kW (36 HP) rotary engines, each in an underwing pod driving a pusher propeller, with a parasol-mounted straight wing, a vee tail, and fixed tricycle landing gear with an arresting hook.
The Hermes 450 can operate at altitudes of up to 6,100 meters (20,000 feet)
for up to 24 hours. It can be fitted with a day-night imaging turret or a
maritime search radar. It is now in Israeli Air Force service, and has been
used for surveillance in fighting with Palestinian militants in the West Bank
and Gaza. Two were also obtained by the US Border Patrol in 2004 to provide
surveillance over the US-Mexican border, and as mentioned earlier, the Hermes
450 was selected for the British Watchkeeper program.
HERMES 450:
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spec metric english
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wingspan 10.5 meters 34 feet 5 inches
length 6.1 meters 20 feet
payload weight 150 kilograms 330 pounds
empty weight 450 kilograms 990 pounds
max loaded weight 800 kilograms 1,765 pounds
maximum speed 175 KPH 110 MPH / 95 KT
service ceiling 6,100 meters 20,000 feet
endurance 24 hours
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Silver Arrow sells a version of the Hermes 450 with a single 39 kW (52 HP)
engine driving a pusher propeller. This variant is designated the "Hermes
450S". Specifications are much the same, except for slightly lower
performance. The company also sells a "stretched" variant, the "Hermes 900",
with the same general configuration but about twice the weight, twice the
horsepower, and retractable landing gear. The Hermes series saw combat
during the war in southern Lebanon in 2006; details of their operations were
not released, but it is believed in some cases the UAVs were armed and
performed strikes on Lebanese Shiite Hezbollah fighters.
In addition, Silver Arrow sells the larger "Hermes 1500", which is powered by
twin Rotax 914 engines, with 75 kW (100 HP) each and mounted in tractor
configuration in wing nacelles. Like the Hermes 900, it has retractable
landing gear.
SILVER ARROW HERMES 1500:
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spec metric english
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wingspan 15 meters 49 feet 2 inches
length 9.4 meters 30 feet 10 inches
payload weight 350 kilograms 770 pounds
max loaded weight 1,500 kilograms 3,300 pounds
maximum speed 240 KPH 150 MPH / 130 KT
service ceiling 9,150 meters 30,000 feet
endurance 30 hours
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The Israelis are interested in developing a long-range UAV that would be able
to overfly Iran. This machine would have self-defense systems and would
presumably be stealthy. However, if any work is actively being done on it,
it remains a secret.
* In the mid-1990s, a consortium of three Israeli companies, IAI, Rafael, and Wales, attempted to design an endurance UAV for boost-phase intercept of tactical ballistic missiles. The result was the planned "HA-10" UAV, which would have carried two or three interceptor missiles derived from the Rafael Python air-to-air missile. However, BPI turned out to be far too technically challenging, and the HA-10 project was abandoned.
The Israelis still feel that endurance UAVs can be used effectively against TBMs, but they believe that the mission of these aircraft should be to locate TBM sites for attack by air-to-surface missiles before they can launch, a task which is seen as easier than BPI. Missile intercept would be performed by "terminal defense" systems such as the Israel Arrow anti-missile.
Israeli defense officials would like to have a set of low-speed UAVs with an endurance of 60 hours, with one UAV carrying targeting sensors and the other UAV carrying missiles. The UAVs would be able to engage and destroy almost any large ground target, not just TBM launchers, from a long distance away. These endurance UAVs would have "stealth" design features to allow them to observe without being seen. The sensor UAV would operate at about 20,000 meters (65,000 feet), while the missile UAV would operate at about half that altitude, and would have the capability of inspecting a target passed on to it by the sensor UAV before launching a strike on the target. The US Missile Defense Agency is cooperating with the Israelis on the issue.
* In late 2005, BAE Systems of the UK unveiled a prototype of the "High Endurance Rapid Technology Insertion 1A (HERTI-1A)" MALE UAV, which looked like an unmanned sailplane with a piston engine driving a pusher prop mounted on the back of the main fuselage. The HERTI-1A's airframe was built by J&AS Aero Design of Poland. The UAV has a weight of 450 kilograms (990 pounds), including a payload of up to 150 kilograms (330 pounds); a span of 12.6 meters (41 feet 4 inches); a ceiling of more than 6,100 meters (20,000 feet); a range of up to 3,000 kilometers (1,865 miles), and an endurance of up to 30 hours. BAE Systems is offering the machine for both military and civilian applications; it appears that it has been used by the Royal Air Force in Afghanistan.
* In mid-2001, the French Air Force awarded a contract for an endurance UAV named "Eagle 1", being offered by a collaboration between the European Aerospace & Defense Systems (EADS) company and IAI. Eagle 1 is a straightforward derivative of the IAI Heron, with a bulbous nose like that of the US Global Hawk and a belly antenna dome, presumably for a SAR. It will be fitted with French-Israeli avionics as specified by the French Air Force.
The Eagle 1 prototype, essentially a Heron with the belly dome and no doubt some Eagle production avionics, performed its initial flight from the Ein Shemer airfield north of Tel Aviv in Israel on 2 June 2003. Full operational kit for the UAV will include an automatic takeoff and landing system, an EO/IR imaging turret, a laser target designator, an Elbit-built SAR-MTI sensor, and a satellite communications link.
An "Eagle 2" with a turboprop engine, based on the Heron-TP, is in the works as a solution to the multinational EuroMALE requirement. The Eagle 2 will be able to loiter for 24 hours at 15,240 meters (50,000 feet) with a 450 kilogram (1,000 pound) payload. EADS is investigating weapons carriage on both the Eagle 1 and Eagle 2.
EADS is also promoting an "Advanced UAV" concept powered by twin small turbofans and featuring a modular construction. In an endurance configuration, the Advanced UAV would have long wings; in a tactical, low-altitude reconnaissance configuration, it would have short wings for high speed. The idea actually is interestingly reminiscent of the variations in configuration of the Ryan Lightning Bug drones.
* The French Sagem company formed a collaboration with General Atomics to compete for the same contract with a variant of the General Atomics Predator, designated "Horus" after the Egyptian hawk god, but the proposal was rejected as too costly.
Sagem is promoting a new medium-altitude, high endurance version of their Sperwer, the "Sperwer LE (Long Endurance)", with a weight of 350 kilograms (772 pounds), a wingspan of 6.5 meters (21 feet), and a length of 3.5 meters (11 feet 6 inches). First flight was in late 2001.
The Sperwer LE is being designed to cruise at 6,000 meters (20,000 feet) for twelve hours. It is intended to compete with UAVs such as the E-Hunter and the Eagle 1. It will carry a 50 kilogram (110 pound) payload, including a day-night stabilized imaging system, plus a "Samir" missile warning system derived from an earlier system used on the Dassault Mirage 2000 fighter. It will include a high-speed RF datalink to allow it to communicate with other UAVs or its ground control station.
* Meteor of Italy is now promoting a new piston-powered tactical UAV, the "Falco", more or less in the same class as the Predator. The Falco has a traditional tactical UAV configuration, with fixed tricycle landing gear, a pusher prop, and a twin-boom tail, but it is larger, since it is intended for the medium-endurance niche; is made mostly of composites; and has sensor systems built into a "glass nose", not a turret.
The Falco has a wingspan of 7.2 meters (23 feet 7 inches) and a length of 5.25 meters (17 feet 3 inches). Maximum speed is over 233 KPH (126 knots), operating altitude is over 6,000 meters (19,700 feet), and the machine can take off from a 60 meter (200 foot) airstrip or flight deck. It can carry a full 70 kilogram (155 pound) payload for eight hours, or a smaller payload for 14 hours. It has a hardpoint under each wing, with each hardpoint having a load capacity of 25 kilograms (55 pounds).
The current Falco is powered by a 49 kW (65 HP) gasoline engine. Meteor is working on a new variant with a 60 kW (80 HP) fuel-injected engine that can burn diesel fuel.
* Kentron of South Africa is now working on long-endurance UAV in the class of the Predator, named the "Bateleur". Artwork shows it to have a strong resemblance to the Predator, except for winglets at the ends of the wings, twin tailfins, and a pod on each inner wing. It is to have a payload capacity of 200 kilograms (440 pounds) and endurance of 18 hours or more.
* The Russian Sukhoi organization has released notional drawings of three endurance UAVs currently in design, designated "Zond 1", "Zond 2", and "Zond 3". Zond 1 and 2 are similar designs, along the lines of the US Global Hawk. They both feature long-span wings, twin turbofan engines, and a vee tail. The differences are in mission payloads. The Zond 1 carries an air-surveillance phased-array radar in a radome on the top; the aircraft has a top speed of 600 KPH (370 MPH / 325 KT) and an endurance of 18 hours. The Zond 2 carries EO/IR imagers and a SAR; it has a top speed of 715 KPH (445 MPH / 385 KT) and an endurance of 24 hours.
Zond 3 is more along the lines of the US Predator, with a pusher propeller and inverted vee tail. It has a top speed of 250 KPH (155 MPH / 135 KT) and an endurance of 12 hours. It is unclear if any Zond prototypes have been flown. Sukhoi has promoted these machines for civil applications, but of course they clearly have military applications.
