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REMOTE CONTROL BY BOB YOUNG Unmanned aircraf t – the early developments As discussed last month, the development of unmanned aircraft goes as far back as the 1890s but the first really serious attempts were made by the British in 1917 in designing aerial targets (ATs). These early attempts were monu­mentally unsuccessful. In America, the Army and Navy undertook “Aerial Torpedo” programs, both using the principle of the Sperry Gyroscope to control the UMA (unmanned aircraft) by autopilot rath­er than remote piloting by radio. This early development of the autopilot technique was to stay with UMAs and in most cases the radio control inputs are fed to the controls via the what little data is sent to the UMA does arrive safely. Such techniques as frequency hopping, high speed transmission of data, digital encoded transmissions and many more exotic techniques are employed in an effort to make the control link secure. As we have already noted, these techniques are very effective, as the sur­vival rate of these little vehicles is RAE (Royal Aircraft Establishment) achieved the launch and stability breakthrough that led to the decision to develop the Larynx (Long-Range Gun with Lynx Engine). This UMA, though its warhead trials were a failure, was way ahead of anything flown elsewhere. The modern miniature warheads developed for missiles and RPVs are a real work of art (if killing people can be considered an art form) and show the absolute genius humans can bring to bear on the development of systems of destruction. Some of these warheads are quite tiny in terms of explosive force and one to five kilograms of explosives is quite typical. The trick is to make this charge do the work of a much bigger bomb. The spring technique “The concept of the attack drone resurfaced at the outbreak of World War II. The best remembered examples were perhaps the German V1 and the Misteln, a piggy-back composite aircraft” autopilot, with the autopilot remaining the primary means of stability and con­trol. There are many reasons for this, the most important being that the UMA then becomes an autonomous vehicle and is relatively immune to jamming. If a radio link were required for stability via the pilot back at base, interference could easily bring the bird down. As it is, radio designers go to incredible lengths to make sure that 80  Silicon Chip now very high. However, when flown in 1918, the Navy-Curtiss autopilot controlled design was no more successful than the British ATs. Only one of the 12 built worked properly. The Army “BUG”, de­signed and built by Dayton-Wright, was more successful but the need for such weapons evaporated with the ending of hostilities in 1918. Development work was recommenced in the early 1920s and the One very effective technique is to place the charge inside a tightly compressed spring. When the charge explodes, this spring opens out into many broken, but quite long pieces which are capable of cutting the wing off an aircraft or doing equally serious damage to other parts of the airframe. It must be remem­bered here that modern aircraft are so fully packed that it is almost impossible to put a piece of shrapnel through them without damaging something, thus rendering the aircraft unserviceable even if it does get home. A friend of mine once saw the results of an accidental missile strike on a warship. He told me that one of these spring fragments went through the side of the steel super­structure and left a zig-zag cut as clean as a whistle. Aircraft are not made of steel plate. Obviously much progress has been made in warhead design since 1925. AUSTRALIAN MADE TV TEST EQUIPMENT Battleship vulnerability 12 Months Warranty on Parts & Labour The real impetus for UMA development came as a result of General “Billy” Mitchell’s demonstration of the vulnerability of battleships to aerial bombardment. Nav­ ies around the world sat bolt upright at the news that a single aircraft had sunk a bat­tleship. This was shape the Pacific war, with the Japanese whole­heartedly adopting the methods advocated by Mitchell and develop­ing carrier-based bombers and torpedo aircraft. As a result of the Mitchell trials and the success of the Larynx system, the RAE modified three Fairy IIIF floatplanes into Fairy Queen radio controlled targets, to test the ability of Royal Navy gunners. Off Gibralter in January 1933, one of these flew for two hours through concentrated AA fire from the Home Fleet which failed to register a single hit. Without further ado, the Air Ministry issued Specification 18/33 for a dedicated radio-controlled target, which resulted in the de Havilland Queen Bee. Thus, the UMA came of age. More than 400 of this Moth Major/Tiger Moth hybrid, the world’s first mass produced target drone, were eventually built. SHORTED TURNS TESTER “Other UMA experiments involved aircraft as large as the B-17 (Flying Fortress) and PB4Y 4-engined bombers, primarily as explosiveladen, expendable UMAs” Built-in meter to check EHT transformers including split diode type, yokes and drive transformers. $95.00 + $4.00 p&p HIGH-VOLTAGE PROBE Built-in meter reads positive or negative 0-50kV. For checking EHT & focus as well as many other high tension voltages. $120.00 + $5.00 p&p DEGAUSSING WAND Great for computer mon­­­it­ors. Strong magnetic field. Double insulated, momentary switch operation. Demagnetises colour picture tubes, colour computer monitors, poker machines video and audio tapes. 240V AC 2.2 amps, 7700AT. $85.00 + $10.00 p&p TUNER REPAIRS From $22. Repair or exchange plus p&p. Cheque, Money Order, Visa, Bankcard or Mastercard TUNERS 216 Canterbury Rd, Revesby, NSW 2212, Australia. Phone for free product list Phone (02) 774 1154 Fax (02) 774 1154 The USN tested its own version of an aerial target with similar dismal results (for the gunners). However the first US targets were not ordered in quantity by the Army Air Force until 1940 and by the Navy in 1942. Interestingly enough, these were provided by Radioplane, a small company founded in 1939 by the Hollywood actor, Reginald Denny. Denny began experimenting with radio-controlled model aircraft in 1935 and Radioplane was estab­lished to commercially develop R/C models. Radioplane ultimately became the Ventura division of North­rop, the world’s largest producer of target aircraft. The concept of the attack drone resurfaced at the outbreak of World War II. The best remembered examples were perhaps the German V1 and the Misteln, a piggy-back composite aircraft. Misteln was comprised of a bomber carrying a radio-controlled fighter to the target. The fighter was launched and guided to the target from the bomber. Less well known was the American Interstate TDR-1, an ex­pendable UMA with a 2,000lb (907kg) warhead which was used with some success, albeit briefly, in the Russell Islands campaign in Autumn 1944. It was guided by a Grumman Avenger mothership and of the 46 launched, 29 reached the target and 21 scored direct hits or near misses. Other UMA experiments involved aircraft as large as June 1993  81 REMOTE CONTROL – CTD the B-17 (Flying Fortress) and PB4Y 4-engined bombers, primarily as explosive-laden, expendable UMAs. The above aircraft, whilst strictly defined as unmanned aircraft, fall more towards the definition of primitive guided weapons or missiles and serve to illustrate the fine distinction between what constitutes a guided missile and an expendable UMA. Post-war, the acquisition of German control and guidance technology was channelled with enthusiasm into the development of guided missiles. A residual of this enthusiasm trickled down into the UMA area, mainly in Wagner’s “Lightning Bugs and other Reconnaissance Drones”. As pointed out in last month’s story, the recovery rate of these vehicles was remarkable and from the 3,435 sorties undertaken in Vietnam during the years 1964-1975, the bird re­turned home in more than 83% of cases. This was to improve with the development of more sophisticated technology to a final figure of well over 90% in the last four years of that war. Nor was this recovery rate the result of ineffective AA fire or missile firings by the North Vietnamese. From the early 1960s to 1971, the Ryan “The real hub of activity in the RPV field has proven to be the Middle East, with the Israelis being the leading exponents in the design & development of such vehicles” the belief in the UMA as a target with perhaps a grudging acknowledgement of their potential as reconnaissance aircraft. Thus we saw a very limited use of radio controlled F6F Hellcats during the Korean War and a reversion to the belief that the only real role for the UMA was in the target field. Then suddenly, the Cuban Missile crisis changed all of that. In 1962, a Cuban SAM (Surface to Air Missile) brought down an American U-2 reconnaissance aircraft with the loss of its pilot and interest was suddenly focused on the UMA as a reconnaissance vehicle. The result was the development of the Teledyne Ryan 147 (alias AQM-34). Vietnam The story of how this “Son of Firebee” eventually grew from the original BQM-34 target drone into a huge family of multi-capable un-manned aircraft is a part of UMA folk-lore. They were used for high, low and medium-altitude photographic and video reconnaissance, ECM (electronic countermeasures), decoy, leaflet-dropping and damage assessment missions during the Vietnam War. This was brilliantly told in William 82  Silicon Chip 147s were also used for reconnaissance flights over mainland China and it was unofficially reported that up to 20 MIG fighters made between 30 to 50 passes at the first of these before bringing it down. China’s own Chang Hong 1 began life as a reverse engineered Ryan 147 and is still in service today. With the ending of the Vietnamese War, the Ryan 147 had demonstrated conclusively that RPVs (the new “in” term for UMAs) could deliver the goods, were eminently survivable, put no human crew at risk and were an order of magnitude cheaper than manned vehicles. Despite that, the interest in RPVs dropped back to an almost non-existent level in the USA, despite a plethora of hopeful new designs from a defence industry which believed it had a discovered a new bandwagon on which to climb. The one notorious exception was the US Army’s Aquila project which developed into a textbook example of how not to procure a cheap and effective operational system. Thus, the Aquila grew from a small 54.4kg vehicle capable of carrying a 13.6kg payload for 1.5 hours into a vehicle capable of tasks which includ- ed communications relay, weath­ er reconnais­ sance and electronic warfare, as well as a myriad of other func­ tions. Weight grew to 120kg (gross) with a 25kg payload and an endurance of well over 3 hours. Added to this was a stealth exterior. The final cost of this project blew out from an original estimate of US$250,000 per unit to over US$1,000,000 per unit, hardly a low cost, throw away item. Still, it is considerably cheaper than a $40,000,000 manned aircraft and the life of the pilot is not at risk. Sadly, the project was cancelled in 1989 as being too expensive after some 15 years of development and test­ing. In fairness to the above project, much of the confusion which was to result in the high final cost was brought about by a constant moving of the goal posts. This problem of constantly changing the final aims of any project is the bane of the engineer’s life and goes on in all fields of technological endeavour. Once the top brass issue the latest decree, they tend to forget all that has gone on before and the engineering department carries the can when the cost and time overruns come in. Middle East activity The real hub of activity in the PRV field has proven to be the Middle East, with the Israelis being far and away the leading exponents in the deployment of such vehicles. The first RPVs to appear there were about a dozen Ryan 124-Is acquired by Israel in 1972-73 as decoy drones and high altitude photographic reconnaissance vehicles. A number of Northrop BQM-74 Chukar targets were also converted by Israel for decoy use, both types proving their worth during the Yom Kippur War. From that point on, Israel was sold on the value of RPVs, to the point where that country is now demonstrably this leader in the field. Yet the beginnings of the home-grown Israeli RPV industry could hardly have been more modest. It is said that the most expensive single item in the first domestic RPV prototype was a $600 Sony TV camera, whilst the launching platform was the roof rack on the designer’s car. Next month, we’ll look at the role of the RPV in the Middle Eastern wars of SC the past 20 years.