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  • IN FOCUS: Israel embraces micro and mini unmanned systems

IN FOCUS: Israel embraces micro and mini unmanned systems

Israeli Defence Force (IDF) doctrine holds that to attain full command of a given area, a ground force must be continuously present while the air force is on call to support from above.

But the manufacturer Israel Aerospace Industries (IAI) offers a different take - and the tools to perform it. A company source explains that by using unmanned air systems (UAS), hovering intelligence platforms and stand-off sensors on aircraft, the air force can achieve sustained dominance, saying: "Some of these aerial systems should be operated by the infantry [but] the ground force can stay in safe areas and move in only when the targets are well defined and precisely located."

BuleBird Boomerang UAV, BuleBird

  © BlueBird

BlueBird's calapult launched Boomerang UAV has a range of 35km

IAI's Panther tiltrotor UAS uses an innovative automatic flight control system to manage the transition between phases of flight. The Panther can be made to take off or land with simple clicks of the operator console.

The Panther is powered by three ultra-quiet electrical motors, explains IAI. It has a take-off weight of 65kg (143lb) and an endurance of 6h. A smaller Mini Panther design, meanwhile, has a weight of just 12kg when taking off and its endurance is 2h.

The second such tool is the IAI hovering aerial vehicle (HAV), a purely electrically powered, tethered, airborne platform which can be used for observation, surveillance and other applications. The HAV can carry a payload of up to 20kg and operate up to a maximum altitude of 30ft (100m). It combines an electrically powered aerial platform and a ground system which includes the means for automatic deployment, cables, and a mission management unit. The third tool developed by IAI is the Ghost vertical take-off UAS.

And the manufacturer is also developing the Harlim, a solar-powered system that takes off when the fighting starts and is in the air for its duration; the Butterfly, a micro UAS with flapping wings; and the Mosquito super-mini UAS.

With mini and micro UAS designs becoming more popular, IAI seeks advanced propulsion systems for these small platforms, with a focus on batteries and hybrid systems as alternatives to the fuel cells that have entered the market in recent years.

A senior IAI source says the introduction of fuel cell power packs for UAS is proceeding at "a slower pace than we thought", with some lithium-ion batteries are the near-term preferred solution for small vehicles. "These batteries have been improved in recent years, and they are giving good results," says the source.

Hybrid power packs, meanwhile, are in development in the USA, Europe and Asia. The US Air Force has asked industry to develop a hybrid power pack that will weigh less than 9kg and be capable of powering a UAS for mission durations of 4h.

A hybrid power pack is based on an internal combustion engine that drives a small auxiliary power unit (APU). This APU recharges the batteries that power the propeller.

IAI's Ghost has a maximum take-off weight of 4kg, an endurance of 25min, a speed of 35kt (65km/h), and an operational range of 4km (2.1nm). The mini UAS is powered by electric motors and will be capable of automatic take-off and landing.

While all these development efforts continue, IAI is upgrading its mini UAS designs. It is, for example, marketing a new variant of the Bird Eye 650, with a new propulsion system powered by fuel cells allowing 6h endurance, compared with 3h for its existing version. The variant also weighs less and includes an advanced folding launcher.

"The improvements of the Bird Eye 650 make it an even more cost-effective system," says Tommy Silberring, general manager of IAI's Malat division. "The Bird Eye 650 was developed using experience we gained from the Bird Eye 400, which in turn was developed based on our knowledge of other UASs, such as the Heron."

The Bird Eye 650 provides real-time day/night imagery data for urban operation and "over-the-hill" intelligence. It consists of three UAV platforms, electro-optic and infrared (IR) payloads, a portable ground control system, a data link, and a power source and repair kit. The entire system is man-portable and can be deployed in the field by two people.

The portable ground control system is lightweight and allows for automatic operation of the UAS and its payloads, and the data link allows for digital ground communication. The system uses a man-portable remote video terminal and a ground control element.

While companies develop more mini and micro UASs, some are entering service in the Israel's infantry units. The IDF has completed a series of operational tests with the Elbit Systems Skylark II UAS, which was selected as the infantry's brigade-level system.

The Skylark II was selected after the other bidder, IAI, was not ready with the tiltrotor Panther UAS. The defence ministry rejected IAI's request to postpone the decision.

The Skylark II is designed for data collection and target-marking at mission ranges exceeding 60km. Elbit says it uses a highly deployable single vehicle equipped with an integral launcher for point launch and recovery and an advanced, dual ground control station.

The company has demonstrated that the Skylark II full-cycle operation is possible with a two-person crew. The aircraft's gimballed, triple-sensor payload includes a colour charge-coupled device (CCD) day camera, a third-generation thermal-imaging night camera and a laser illuminator. Mission range is 60km, with a 4h endurance. The maximum ceiling of the UAV is 15,000ft (4,570m), with a maximum take-off weight of 65kg and a 6.5m wingspan.

Elbit says that the propulsion system of this UAS enables medium-altitude as well as low-altitude covert flights for high-quality imagery and operational reconnaissance under cloud cover with no risk of exposure.

Also in development is the Skylark I-LE (long endurance), a derivative of the Skylark I operational with several armed forces worldwide, including Israel and Afghanistan. This mini-UAS is tailored for lower echelons self-support reconnaissance, performing close-range beyond-the-next-hill missions, and is equipped with a secure digital data link.

Skylark I-LE is equipped with an Elbit thermal night sensor weighing just 700g. The payload's capabilities include very wide area coverage, continuous tracking of moving targets and a higher resolution rate than any of its predecessors.

Ghost UAV, IAI

 © IAI

Israel Aerospace Industries has developed the Ghost - a vertical take off UAS

The Skylark I system set a world record for its class in high-altitude flight, climbing to an altitude exceeding 16,000ft, and has demonstrated outstanding performance in weather conditions ranging from arctic to equatorial, Elbit says.

In 2009 the company was awarded an initial $40 million contract by the Israeli defence ministry to supply the Skylark I-LE mini-UAS to all IDF ground force battalions. The contract includes training and logistics support and has options for more systems, bringing the potential total value to $100 million.

Deliveries will be over the next few years, subject to the IDF's requirements and procurement process. During its operation "Cast Lead" in Gaza, the IDF used its already operational Skylark UAS for intelligence-gathering and real-time coordination between ground, air and sea forces.

The Skylark I-LE has a 2.9m wingspan, 3h endurance and a 15km mission radius equipped with a Controp gyro-stabilised payload. The maximum take-off weight is 6.1kg by day and 6.3kg by night, launched by hand, bungee or rail. Operational altitude is 9,840ft, with deep-stall and airbag recovery possible. The LE's electric propulsion emits very low noise levels.

Aeronautics Defense Systems, a fast-growing Israeli UAS manufacturer, is producing two types of a mini air vehicle: the Orbiter 1 and its larger version the Orbiter 2. The former has a wingspan of 2.2m, a maximum take-off weight of 7kg and an endurance of 3h, compared to the latter's respective figures of 3m, 9kg and 4h.

Innocon is a latecomer to the Israeli UAS industry. It has sold its Micro Falcon UAS to the Peruvian army in a deal that includes its Naviator flight computer, which manages all flight parameters including take-off and landing. A ground station will also be supplied.

Micro Falcon is Innocon's lightest UAS, weighing only 6kg. Designed for soldier-level missions of over-the-hill observation, it operates at an altitude of 1,000ft and can stay airborne for 2h by day or night. Rugged, with box-type wings, the Micro Falcon can land upside down using a parachute, thereby increasing survivability and cutting down on redeployment time cycle.

The Peruvian army is to equip the Micro Falcon with the Controp stabilised mini payload (STAMP). This payload has two versions: the D-STAMP, with a CCD camera for daylight applications; and U-STAMP, with an uncooled IR camera for night applications. Each gyro-stabilised payload weighs less than 1kg.

Another Israeli UAS manufacturer, BlueBird, offers the SpyLite, a mini system with a maximum take-off weight of 8kg, an endurance of over 3h and an operational range of 50km. The SpyLite has a wingspan of 2.4m and is recovered by a combination of parachute and airbag.

BlueBird also manufactures the 1h-endurance MicroB, with a wingspan of 99cm and a launch weight of 1kg.

Slightly different lines of products are manned helicopters converted to fly with a black box instead of a pilot, and a new breed of vertical short take-off and landing (VSTOL) unmanned platforms.

IAI is developing unmanned helicopters for resupply and medical evacuation missions in the combat zone. After evaluating different proposals, it concluded that converting a heavy helicopter was the best option.

Avi Bleser, marketing director of IAI's Malat UAS division, says that tests have been performed with a Bell 212. To prove the accuracy of the flight control system, a basketball was attached to the helicopter with a rope, and the flight control system manoeuvred it again and again so that it entered a basket placed on the ground. "The idea is to control such an unmanned helicopter using the same ground station used for UAS," says Bleser. "This will ensure commonality and ease of operations."

The IDF's ground forces have initiated a research and development programme aimed at producing "hovering platforms" capable of lifting heavy weights, after Elbit won a contract to develop a cargo UAS for the military.

The project has been dubbed the Flying Elephant and is intended for resupply missions to the frontline. Elbit's proposal is based on a wheeled cargo pallet that can be loaded with 1 tonne of ammunition, food or water. The pallet is attached to a special parafoil with servo systems that ensure its aerodynamic shape. The Flying Elephant will be able to fly for a "number of kilometres" and will have a GPS system for navigation to the desired supply point.

Sources say the Elbit proposal was selected for its simplicity and the projected time needed to deploy such a system, although it will be limited in its flight altitude and carrying capability.

IAI Mosquito UAV, IAI

 © IAI

IAI's Mosquito is a super-mini unmanned air system that is launched by hand

The need for such a platform reflects lessons learned from the second Lebanon war, where combat units had difficulties receiving supplies from helicopters. The same difficulties were experienced by the medical crews when urgent evacuation was required.

A prototype of Urban Aeronautics' AirMule ducted-fan unmanned platform has completed another series of test flights in which its automatic take-off and landing system was tested, along with its precision hovering feature.

The 6.2m long and 2.2m wide AirMule has an empty weight of 771kg and a maximum gross take-off weight of 1,400kg. It is powered by a Turbomeca Arriel 2 940shp engine, driving a rotor with a diameter of 1.8m. It has a maximum speed of 97kt and can reach a maximum altitude of 12,000ft. Flight endurance is up to 5h, according to Urban, which plans to move the next series of test flights to southern Israel, where there are areas that facilitate the opening of the AirMule's flight envelope.

IAI and Elbit have developed larger UASs in service in Israel and many other countries. IAI's Heron 1 is very active with the Israeli air force in a variety of missions, some highly classified. Elbit's Hermes 450 is also deployed by the Israeli service and has been exported, for example providing the basis for the British Army's new Watchkeeper system.

While at one end of the spectrum UAS have become small and very "personal", at the other end there are very large designs such as IAI's Heron TP, which has a wingspan similar to a Boeing 737.

Taking into account that Israel is revealing only a small part of its UAS portfolio, it can be assumed with great confidence that in the various companies' "Skunk Works"-type departments new designs are under development, with some already performing test flights.

What is certain is that last year the Israeli air force's UASs performed more flight hours than its manned aircraft, and in operational missions.



Among the strangest and most innovative aircraft in the world is the AirMule, built by small Israeli company Urban Aeronautics.

A single-engined vertical take-off and landing aircraft powered by internal rotors, AirMule does not, admittedly, represent a new concept. The US Army tested a similar vehicle in the 1950s - but it was heavy, slow, gas-guzzling and unstable, and was quickly shelved in favour of the clearly superior helicopter.

Yet helicopters are limited by the large open rotor, making them an inelegant solution for roles such as medical evacuation and flight in confined spaces.

Urban Aeronautics president Rafi Yoeli deems the internal rotor concept worth another look: "Materials are much lighter, analysis methods enable saving some more weight, and the most dominant component is really the engine," Yoeli says. "Today, compared to turboshaft technology in the 1960s, they weighed half what they did, and put out twice the power."

Urban Aeronautics Air Mule, Urban Aeronautics

 © Urban Aeronautics

The AirMule's interior fuselage is shaped with an aggressive camber for significant lift

Another major innovation is the network of vanes used to vector thrust from the fans. Controlled by computer, the vanes allow directional control without the AirMule needing to move. It can change position without the need to roll, or stay stable in gusty conditions.

"When you hook up this whole thing into full-authority FBW flight control system, you have the first vehicle in the world that can move in six degrees of freedom independently of each other," Yoeli adds. With endurance and stability issues solved, Urban tackled the problem of speed. Attaching rear-facing fans to the aircraft went a long way to making the aircraft faster, opening vents in the forward fuselage did the rest. The interior fuselage is shaped with an aggressive camber, allowing it to generate significant lift at 100kt-plus (185km/h).

Only one prototype AirMule has been built − a second one is under construction. The aircraft has made 60 tethered flights, Urban says, and accumulated "several hours" of airborne time.

"We've frozen the configuration now, no changes, no more development, everything works very well, and all that we have to do is open up the flight envelope of the test vehicle and get some more airtime on it," Yoeli says. "This is where all the effort will go in the next two years. More flying, more testing, more data, and more field experience with the prototypes."

Funding remains elusive, despite support from the Israel Defence Force and a number of private investors. No orders have materialised, although Yoeli is confident of success once both demonstrators start untethered flight, scheduled for the end of 2012. AirMule is mainly aimed towards the military market, where there are obvious benefits for landing in confined spaces. Yoeli says AirMule has low "detectables" - heat, noise and radar cross-section - in comparison with similar-sized helicopters, and the aircraft can easily fit inside a Lockheed Martin C-130 or Sikorsky CH-53 without disassembly.

Civilian applications such as medical evacuation are another potential market, although Yoeli says unmanned and single-engined aircraft have an uncertain future in that realm. Urban hopes to attach robotic arms to the aircraft and sell it to disaster response agencies and for power-line maintenance.

Sales discussions are under way with a number of major aircraft manufacturers, Yoeli says: "We are advancing with them, we are advancing with others. I am very, very confident. We also know the hurdle that we had to pass. We know where we are technically. I see no show stoppers on the way to making this revolution."





Arie Egozi's blog Ariel View provides running commentary on developments in the Israeli aerospace industry.

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