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REMOTE CONTROL BY BOB YOUNG Unmanned aircraft: current models in service Over the last decade, unmanned aircraft have come into their own & this was demonstrated to great effect in the Desert Storm campaign in the recent Gulf War. Some of these craft are little more than model aeroplanes but they are extremely effec­tive nonetheless. In last month’s column, we looked at the development of unmanned aircraft (UMAs) over the past 80 years and noted the very fine line between UMAs and primitive guided missiles. This distinction is even closer when the modern glide bomb (smart bomb) is considered. With this we are virtually back to the MISTELN concept discussed last month in which a mother ship carries an unmanned fighter to the target vicinity, launches the fighter and guides it to the target. This concept was used by the Germans in WWII with limited success. But the smart bomb was used in the Iraq campaign, again guided from a mother ship, this time with great success. Hardened aircraft shelters (or HAS) proved totally ineffective against these devastating weapons and once again the shape of warfare has shifted and moved on to the next concept. With this blurring of lines of demarcation we are faced therefore with the need to define what we mean by the term RPV, the new buzzword for UMAs. Remotely Piloted Vehicles (RPVs), as the term suggests, covers any vehicle capable of being controlled The Bell Eagle Eye is a tilt-rotor UAV currently under development by the US Department of Defence. It is to be powered by a 313kW turboshaft engine. 80  Silicon Chip at a distance from the actual operator. My full-size remote­ly controlled Volkswagen 1600TLE was strictly speaking an RPV. Thus, the term UAV (Unmanned Aerial Vehicle), another modern buzzword, is probably the more correct term for use in this series of articles. There is a further general agreement on the distinction between the various types of UAVs and these fall broadly into aerial targets, the aerial component of a complex battlefield system and finally, guided weapons. As we have already noted, the days when UAVs were of value only for target practice have long since passed but these still comprise a major grouping and probably the missile target is the most sophisticated of this group. The Australian made Jindivik is one of the most successful of this class of UAVs. However, it is the middle group which forms the basis of this month’s article. It is the value of the UAV as a force multiplier that has become increasingly recognised since the Vietnam War; in other words, its value as a component in a complex battlefield system. This outlook was significantly enhanced as a result of the Israe­li experiences and further as a result of the Iraq War. These events showed a growing need for military equipment, especially in the areas of surveillance, electronic warfare and post-strike dam­age assessment, that does not require a human crew to be exposed to enemy weapons. Here we have a very sophisticated class of UAVs capable of a multitude of tasks which in many cases have great commercial potential. One idea which has intrigued STAND-OFF JAMMERS RPV ON STATION OVER TARGET AREA OUTGOING RPV TANKS SURVEILLANCE SENSOR DATA AND HIGH RATE POSITION FIX POSITION FIX RETURNING RPV FORWARD LINE OF OWN TROOPS LAUNCH AREA INITIAL ACQUISITION POSITION FIX GROUND CONTROL STATION (GCS) PUMICE GROUND DATA TERMINAL (GDT) me for many years is the concept of a very fast courier service using small UAVs for cross city delivery of small parcels. Some of the vertical take off and landing UAVs would be ideal for this serv­ice. What must be remembered with this class of UAV is that they are not independent vehicles but are merely the aerial component in a very complex system and thus comprise the middle grouping of the above classification. This system can be comprised of fixed or mobile control and mission planning stations, launch and recovery equipment or vehicles, transporters and data receiving and processing terminals (see Fig.1). The problems of launch and recovery are major in a combat situation and force a further division into sub-classes and in many instances, they influence the design of the UAV itself. A good example of this is the development of the TRUS (Tilt-Rotor study and demonstration UAV system) program. This project is intended to provide ship-based vertical take off and landing UAVs for OTH (Over The Horizon) surveillance and targeting for USN and NATO surface vessels. This program also provides an excellent example of the complexity and sophistication not only of the UAV itself but of the business network required to bring such a complex unit into being. In the second half of 1991, the Bell Helicopter division put together a design proposal for a little Tilt Twin Rotor Vehicle much along the lines of the much troubled Osprey Tilt Rotor Transport aircraft. Named the “Bell Eagle Eye”, the span over rotors is approximately 5.9 metres and the length 4.9 metres. Power comes from one Allison turbo­ shaft rated at 313kW. The Bell team includes Israeli Aircraft Industries, TRW, Allison, Honeywell, Unisys, Scaled Composites and the Stratos Group. IAI contributes the ground control system, data link, mission computer and payload. TRW contributes payload trade-offs, antenna Fig.1: this diagram shows some of the complex infrastructure involved with the launch, guiding and recovery of typical UAVs. Getting them into the air is easy but recovering them under battle conditions can be very difficult. simulation and interoperability, Honeywell the AHRS and other avionics. Unisys integrates shipboard command/control with the airborne data link, while Stratos provides the operational interface. Burt Rutan (Scaled Composites Inc), the famous designer of the around the world lightweight aircraft, is building two Alli­ son-powered airframes and the test flights were scheduled for the second half of 1992. To date, I have seen nothing of the results of this project but the above outline gives some idea of the complexity and sophistication of the modern UAV. Take off & landing Vertical take off and landing is only one approach to the launch and recovery of UAVs. Launch is also quite commonly by conventional take off (ROG, rise off ground), hand launch, air­ craft launch, catapult launch or any of several other methods. In other words, getting the thing into the air is easy. Recovery, however, is another July 1993  81 Little more than a model aeroplane, the electrically powered Pointer UAV is in service with the US Army and was used extensively for surveillance during Operation Desert Storm, Desert Sabe and Desert Shield. It uses a CCD video camera. matter. Battles are rarely fought in ideal terrain and landing conventionally is usually out of the ques­tion. The situation for the over-the-horizon UAV is not so bad and any suitable smooth field within operational range will suffice as a miniature airfield. The smaller, shorter range UAVs and, in particular, ship-launched units have real problems with recovery and thus recourse to parachute and net recovery is most common. The problems of shipboard recovery have forced the development of the vertical take off strangest shaped vehicles yet seen on planet Earth. There are flying saucers (or more correctly, flying dough­ nuts), flying balls, flying venturis, flying torpedoes, flying peanuts, deltas, canards, tandem wings, tractors, pushers, heli­copters, tilt rotors and on and on; an endless stream of creative designs intended to solve awkward problems. If the aerodynamics of these vehicles ever finds their way into manned flight (and I believe they will), we will see some very interesting developments “Because the vehicles are actually unmanned, the airframe design­ers have been given virtually carte blanche in regard to airframe & aerodynamic considerations”. and landing UAV more than any other factor. Try landing a speeding UAV into a small net rigged on the heaving deck of a ship at sea. In fact, the recovery problem and re­ duced safety requirements have brought about a revolution in UAV design. Because the vehicles are actually un­ m anned, the airframe design­ers have been given virtually carte blanche in regard to airframe and aerodynamic considerations. This has spawn­ed a wild profusion of the 82  Silicon Chip in airport design in the near future. From the modeller’s point of view and in fact the military point of view, possibly the most interesting modern UAV is the Aerovironment FQM-151A semi-expendable hand-launched mini UAV. Here is a sailplane straight from the pages of Airborne or any other modern model magazine. Its wingspan is 2.74m, length 1.83m, launch weight 3.6kg, payload 910g and it is powered by a 300W samarium cobalt electric motor. (I wonder if they need a good speed controller?) The electrons for this motor are supplied by two lithium batteries which will keep this handy little vehi­cle moving for 1.25 hours at a maximum speed of 80km/h. Cruising speed is around 35km/h and maximum rate of climb 3.1m/s. The usual operational altitude is in the range of 50 to 300 metres. Every aspect of this UAV is novel and militarily salient. The unit was designed to be operated by one man with a second assisting. The complete system breaks down into two back packs. The first contains the aircraft and the second the shoulder-mounted control/monitor system. The UAV dismantles into six parts and can be reassembled in just 2.5 minutes. It carries a fixed focus TV camera in the nose, angled downwards at 20 degrees from the aircraft’s centreline and giving a 22 x 30 degree field of view. It is radio-controlled over an 8km radius and is gyro stabilised. The Pointer is steer­ able by the monitor and is landed from the deep stall after engine shut down. The monitor/control system is very interesting and appears very much like a shoulder mounted peep show. The monitor is mounted on shoulder braces which place it at face height in front of the pilot. It is completely sealed from light and the pilot looks into the peep window at the monitor screen. The flight controls are mounted on the side of the monitor housing. The transmitter is ground based or portable. This simplicity and flexibility of operation allows some novel uses for the Pointer. The UAV can move to the target under power, which being electric is very quiet, then glide with the motor off to within close range of the target. The motor is then restarted and the UAV climbs away back to base. Being semi-expendable it does not matter if it is brought down by enemy fire at this point. The data it sniffed out is already back home, as the system is a real-time surveillance unit. The camera is a CCD type with resolution of 350 x 380 lines. There are two monitor screens, one showing UAV heading and the other the target information. The monitor is backed up by a Sony 8mm cassette recorder with stereo audio channels, replay with freeze framing, fast slow motion and aircraft heading. The number of uses for this system seems inexhaustible and has continually expanded since being adopted by the USMC in 1988. Designed prim­arily for reconnaissance, surveillance and target spotting, the list has grown to include evaluation of the effec­tiveness of the concealment techniques of US ground troops. Thus, any unit digging in will launch a Pointer to check its own camou­flage from the air and to maintain perimeter security. In the Iraq war, it was operated by the US Army 82nd Airborne Division, 4th M Expeditionary Brigade and the 1st and 4th M expeditionary Force as part of Operations Desert Shield and Desert Storm. Used in the above manner for the first time, it was also used for real-time battle damage assessment, reconnaissance, surveillance and advance warning of enemy movements. Another novel use for Pointer is from a ground vehicle. In this manner, the UAV and pilot can extend the range, depending on the terrain, to around 50-65km, whilst maintaining an opera­tional field of view of up to eight kilometres ahead of and around the ground vehicle; very handy for convoys and armoured columns. However, the Pointer is not without its drawbacks and there were reports of launch difficulties due to high winds. This problem of high winds and low cruise speeds is a serious one for all aircraft, as effective ground speeds can very quickly drop to zero. Thus, a Pointer cruising at 35km/h into a 35km/h head­ wind has a ground speed of 0km/h, whereas a UAV with a 70km/h cruise speed will still have a ground speed of 35km/h and there­ fore will be able to accomplish its mission, albeit with a re­duced range or loiter time. When cruise speed reaches hundreds of km/h, headwinds become less of a problem. Improvements These problems aside, the Pointer appears to have a good future and improvements are already in the system. These include automatic heading and altitude hold, spread spectrum transmission to minimise threat from ECM, increased range (16km), endurance (2 hours) and flight speed. Reduction of airframe and payload weights are also in the pipeline, as is a twin-engined version. All in all, this is a very handy little unit for what is essen­tially a toy aeroplane. Pointer also has a big brother, the HILINE, which is a high altitude long endurance (HALE) UAV for acquisition and tracking of hot airborne targets (launched ballistic missiles, etc). At first glance, the figures on this UAV appear fantastic, with a typical mission profile as follows: carry 45kg payload for 800km, loiter for more than 24 hours and return; range more than 4830km with an endurance of approximately 20-30 hours; range 100km from launch at 25,000 feet; or fly for 15-20 hours at 40,000 feet. The wingspan of this UAV is quoted as 15.24 metres and maximum take off weight as 341kg. It is powered by one 31kW Ackerman OMC-200 tur­ bo­charged 2-cylinder engine. Whilst on the subject of high altitude UAVs, I have seen mission profiles calling for altitudes in excess of 100,000 feet from piston engined UAVs. How they get a piston engine to breathe at that altitude is beyond me. However here we are again at the end of the allocated space. Next month we will continue with a discussion on SC the really exotic UAVs. Product Showcase – ctd from page 67 The end result is that the L-A1 boasts one of the quietest phono stages found in an integrated amplifier irrespective of price. Another outstanding feature is a newly developed master volume control with an unusually low impedance of only 1kΩ. Such a low impedance design reduces thermal and other types of noise to the order of one tenth of traditional designs. Power output is rated at 100 watts RMS from a push pull parallel Darl­ ington design that employs a group of driver tran­sistors for each power section. All stages prior to the output sections are class A. The power output sections are powered by a specially designed toroidal transformer with extremely low mag­ n etic leakage and massive 18,000µF reservoir capacitors that have been specially selected for their outstanding electrical and musical properties. The main amplifier board and phono section boards are glass epoxy, Kenwood claiming that this new material offers excellent electrical characteristics and better rigidity than phenolic resin board. Specifications include 100 watts RMS per channel, with both channels driven into 8Ω from 20Hz to 20kHz with no more than 0.005% THD. Dynamic power is up to 420 watts into 2Ω. The frequency response is 3Hz to 100kHz at the -3dB points, while phono RIAA response is from 20Hz to 20kHz within ±0.5dB. The Kenwood L-A1 stereo amplifier is covered by a 12-month warranty on parts and labour and has a recommended retail price of $3999. For further information, contact Ken­wood Elec­tronics Australia Pty Ltd by phoning (008) 251 697. Nifty little magnifier This combined m a g­n i f i e r a n d tweez­­er set is very handy when you have to examine PC boards for cold solder joints and also to examine the lettering on those teensy-weensy components. And even if you never touch a PC board, it is ideal for getting splinters out of fingers. It sells for just $5.50 from All Electronic Components, 118122 Lons­­ dale St, Mel­ bourne, 3000. Phone (03) 662 3506. July 1993  83