Robotics Technology
This history of robotics is intertwined with the histories of technology, science and thebasic principle of progress. Technology used in computing, electricity, even pneumatics and hydraulics can all be considered a part of the history of robotics. The timeline presented is therefore far from complete.
Robotics currently represents one of mankind’s greatest accomplishments and is the single greatest attempt of mankind to produce an artificial, sentient being. It is only in recent years that manufacturers are making robotics increasingly available and attainable to the general public.
The focus of this timeline is to provide the reader with a general overview of robotics (with a focus more on mobile robots) and to give an appreciation for the inventors and innovators in this field who have helped robotics to become what it is today.
Radio controlled boat complete
Everything started at the end of the 19th century, precisely in 1898. That year the famous inventor Nicola Tesla demonstrated one of his inventions. This invention was a
radio controlled boat intended for military use. You can see a model of it to the left.
Mr. Tesla offered his invention to US navy in order to produce
radio controlled torpedoes. When the navy refused, he offered his invention to the United Kingdom. However, it seems that his invention was just too much to handle for people of that time.
Historic Photos of early land bases robots
Early Torpid
Torpedo fish is an electric ray capable of delivering a stunning shock to its prey and in the eighteenth century an American,
David Bushnell, first applied the name to a weapon of his invention. This first torpedo was simply a mine which was attached to the hull of a ship and exploded either by remote control or by a clockwork fuze. The name was also applied to floating mines and even blazing barrels of pitch carried into harbours by the tide. Within this general application of the name the history of the torpedo up to about 1860 is synonymous with the history of the mine. In order to give a continuous account of the torpedo's development we will go back to Roman days and note the use of fireships to destroy enemy fleets. The use of drifting weapons of destruction, powered by the ocean currents, is not so very far removed from destructive weapons powered by other means as in the present understanding of the name “torpedo”. The next stage in the sophistication of sea weapons appears in 1585 when the Italian Zambelli destroyed a bridge by means of a drifting boat loaded with explosives which were detonated by a clockwork delay fuze.
The first reference to the idea of a self-propelled underwater weapon appears in a play by Ben Jonson where the following dialogue occurs:-
"Thos.-They write here one Cornelius Son hath made the Hollanders an invisible eel to swim the Haven at Dunk irk, and sink all the shipping there.
Pennyboy.-But how is't done?
Cymbal.-I'll show you, Sir, it is an automa, runs under water, with a snug nose, and has a nimble tail made like an augur, with which tail she wriggles betwixt the costs of a ship, and sinks it straight.
Penny boy-A most brave device to murder their flat bottoms."
The Staple of News, Act iii, Sc. 1.
We next find
David Bushnell on the scene again with his submarine, Fig. 1. This remarkable one manpower vessel actually once sank a ship. The operation of the boat is quite obvious from the diagram. The operator used both hands and feet to control the forward and vertical motion by means of screws as well as operating a footpump and rudder. The "torpedo" was a charge of explosive fixed to a ship's hull by means of the woodscrew illustrated and ignited by delayed action fuze. The operator then cranked himself furiously away from tile area before the "torpedo" exploded. The best documented attack by a Bushnell boat was made against the flagship of the British fleet sent to quell the unruly colonists towards the latter end of the eighteenth century. The submarine was successfully positioned under the ship but the woodscrew failed to penetrate the copper sheathing recently introduced onto the hulls of British warships.
FIG. 1. Bushnell's Boat (1775).
Robert Fulton, another American, developed Bushnell's submarine into a more workable version named
Nautilus. With this boat he sank several ships during demonstrations but was not very successful in selling his submarine to the American Navy. Working successively with the French against the British, with the British against the French and finally with the Americans against allcomers, he appears to have been a brilliant inventor and an opportunist. A very glamorised account of Fulton's machinations at the end of the eighteenth century appeared on B.B.C. television in the 1960's as a children's adventure series. Fulton must however be credited with the development of the submarine and its weapon, the mine, to a point where it could be used in wartime.
Soon after Fulton's work the name "Torpedo" became applied to a new class of weapons and the development of the mine continued on its own separate path. This new weapon was the Spar
Torpedo Boat.
Many forms of Spar Torpedo were used, particularly during the American Civil War. Nearly all types were basically the same and consisted of a steam launch having an explosive charge mounted at the end of a long pole projecting ahead of the boat. Fig. 2 shows a typical form as used by the Royal Navy around the 1880's. The launch carried a small crew one of whom viewed the external world through a steel conning tower. The launch approached an enemy ship under cover of darkness and placed the explosive charge against the ship's side and detonated it electrically.
FIG. 2. British Spar
Torpedo Boat.
The spar torpedo was quite successful and one of the most successful types was the
"David "boat operated by the Southern States in the American Civil War. These carried a 60 lb charge on the end of a 25 ft long pole and the explosion was set off 6 ft below the waterline. A crew of eight was used and the boat ran awash. Indeed, it was fitted with hydroplanes for brief dives but these were often fatal.
Although
spar torpedoes were extensively used by the Americans, French, Russians and Chinese, the British considered them "unsporting" and were late introducing them. Indeed, the spar torpedo arrived in Britain just as the automobile torpedo as we think of it today was entering service and the spar torpedo then soon went into a decline in popularity.
Because I wish primarily to cover those aspects of torpedo development not covered in the literature at present I will pass on from the spar torpedo pausing only to mention the Lay spar boat. This was controlled by a crew of one. To each leg and arm was attached a string and each string controlled a different part of the mechanism! It seems quite a knotty problem, and reminds me of the apocryphal "cat-guided bomb" supposedly devised during the recent World War. The cat, slung beneath a bomb dropped in the vicinity of a ship, had strings running from its paws to vanes on the bomb. Appalled by the sight of water beneath it the cat pedalled its way towards the "safety" of the ship and thereby guided the bomb,
via the moving vanes onto the ship. It seems unlikely that the idea could work but the Lay spar boat is recorded with one ship sinking!
The spar boat was easily hit by gunfire and therefore became unpopular. As a result the automobile or "fish" weapon was invented and I shall now begin the story of the weapon known universally as the Torpedo.
Whitehead's Flash of Genius
Robert Whitehead was born at Bolton in 1823, the son of the owner of a cotton-bleaching business. He was apprenticed at 14 to an engineer and there after travelled widely throughout Europe showing the way to improve silk-weaving machinery. In 1856 he became manager of an Austrian engineering company, Stabilimeno Technico Fiumano. The company was heavily engaged in providing engines for the Austrian Navy which was at war with Italy. It was through Whitehead's connections with the Navy that he was approached by a Captain
Giovanni Luppis who had an idea for controlling a spar torpedo boat remotely by two ropes strung out from the tiller. Whitehead built a model but decided that the idea was not viable.
He did however start to think about the problem of setting off explosive charges remotely below a ship's waterline-this being far more effective than above water bombardment. In 1866 his ideas took shape in the form of the first automobile torpedo.
The weapon was built with the help of Whitehead's 12 year-old son and an old workman. The exact form of this first weapon is not known because Whitehead never revealed drawings even many years later and refused to describe the machine to inquirers. Eyewitness accounts describe it as blunt nosed "like a dolphin" with four long fins extending almost along the whole body length. The engine was driven by
compressed air stored at 370 p.s.i. and regulated to approximately constant speed by a simple valve. The engine is generally described as a twin cylinder Vee but this probably refers to the later models of 1868. The original engine was based on two eccentric cylinders having a sliding vane to divide the volume into two parts. In this fashion the air pressure caused direct rotation of the outer cylinder which was coupled to the single propeller.
The weapon was designed to be fired from an underwater tube and a constant depth was aimed at by means of a hydrostatic valve acting directly on the elevator controls. Azimuth control was simply by means of trim tabs set by trial and error over a 400 yards range at Fiume. The weapon achieved about six and a half knots to 200 yards and a further 100 yards at lower speed. The propeller speed on this first weapon was about 100 r.p.m.
The depth keeping on this first weapon was very erratic. Within two years two new weapons had been produced which incorporated a device to be known for decades afterwards as "The Secret." This consisted of a hydrostat-pendulum combination after the fashion of Fig. 3. The simple hydrostat controlled depth according to the law
d2D/dx2 is proportional to D0-D
where D0 is the set depth and x is the distance run. Such a control law has no inherent damping and as a result the original weapon oscillated wildly. The introduction of the pendulum by means of the lever system illustrated introduced an additional term in the above equation proportional to pitch angle which is very nearly proportional to depth rate. Thus a damping term has been introduced. The depth errors were found to reduce from +/-40 ft to as little as +/-6 in. Such was the success of Whitehead's "Secret" that it remained in use virtually unchanged until the end of World War II, a remarkable tribute to a great Victorian engineer.
FIG. 3. Pendulum-Hydrostat depth gear of early torpedoes.
In 1868 Whitehead demonstrated two new models before representatives of the Austrian Navy; a 14 in and a 16 in type. The weapons carried wet gun-cotton warheads and achieved speeds of about seven knots to about 700 yards. Fig. 4 shows the probable form of these early weapons. The propeller is shrouded to prevent damage and a large azimuth control vane is at the rear. These two features were soon to disappear however.
FIG. 4. Probable form of
Whitehead Torpedo (1868).
The Austrian Naval Officers attending the trials were impressed sufficiently to order weapons to be produced but were unable to buy the patent rights outright.
British Torpedoes Enter Service
In the autumn of 1869 Royal Navy representatives visited Fiume and reported favourably on the weapons being tested. As a result Whitehead was invited to England to demonstrate the ability of his weapons. He brought two types of torpedo with him, a 16 in. by 14 ft. carrying 67 lbs. of wet gun-cotton and a second weapon of 14 in. diameter and a little under 14 ft. in length. This latter weapon carried a warhead of dynamite weighing 18 lbs.
Table 5 summarises the main characteristics of these and later weapons.
The weapons were fired either from the surface or from a submerged tube built by Whitehead into
Oberon. Over 100 firings were made during September and October of 1870, the average weapon performance being seven knots to a range of 600 yards.
As a grand finale a wooden coal hulk was moored off Cockleshell Hard and surrounded with protective nets. A 16 in. weapon with its warhead charged by Professor F. A. Abel was fired from a range of 134 yards. The weapon, determined to demonstrate its potency, went around the net and blew a hole measuring 20 ft. by 10 ft. in the old corvette and it sank at once. Faced with such conclusive evidence of the weapon's capability the Royal Navy ordered a batch of Whitehead torpedoes which were received in 1870.
It was most appropriate therefore that one century later a new torpedo trials ship should have been launched with the name E.T.V.
Whitehead.
Two types of weapon were received from Whitehead's works at Fiume; these being 14 in. and 16 in. diameter. In 1871 the Admiralty bought the manufacturing rights for £15,000 and production was started at the Royal Laboratories, Woolwich the following year. This sum of money seems very small for such an important weapon especially when only a decade later a certain Mr. Brennan was paid nearly 10 times as much for the rights of an inferior type of torpedo.
The example of the Royal Navy was quickly followed by the French, Germans and Chinese and soon Whitehead was exporting his torpedoes around the world. Several countries started building their own pirated copies of the Whitehead but these were notably unsuccessful. The stringent specifications laid down by foreign navies caused Whitehead to give consideration to the improvement of performance. He appears to have regarded the weapon as primarily for use in harbours against moored ships. Under these circumstances a speed of only seven knots is acceptable and the main areas for improvements lie with the accuracy of steering and the reliable operation of the impact fuse. However, the Germans specified a weapon performance of 16 knots to
550 yards. Whitehead carried out various improvements including the replacement of the twin cylinder Vee engine by a three-cylinder engine built by Peter Brother-hood, Ltd., of Peterborough. Thus by 1875 a 14 in. weapon was produced having a performance of 18 knots to a range of 550 yards.
In 1872 Whitehead bought the firm and re-named it Silurifico Whitehead. A remarkable feature of this story is the instant success of the novel weapon. The very first experimental torpedo worked well and was being mass produced for export within four years. An envious record for any new product!
With the introduction of the new engine and
contrarotating propellers (this latter by a foreman mechanic at Woolwich) no significant improvements were then made until the introduction of the gyroscope for azimuthal steering in 1895. Fig. 5 shows the transitional form of the weapon in about 1875. The extended fins thereafter were not needed because of the lack of roll forces. Fig. 5 shows typical Fiume built torpedoes of the 1880s period with their pointed noses and small control fins with the control surfaces placed aft of the propellers. This latter feature distinguished Fiume weapons from the Woolwich types (Fig. 6) which carried the surfaces ahead of the screws. The latter practice persists (unfortunately) to the present time.
FIG. 5. A selection of Fiume weapons (c1874-1880).
FIG. 6. R.G.F. Weapons (c1894).
Weapons of various types were produced during the first few decades of the life of the automobile torpedo. In particular, many obscure types of unorthodox propulsion were produced in the United States, as we shall see. The Whitehead type did not however undergo significant charge although many new Mark numbers were introduced.
Table 3 summarises the main weapon types and their performances. It can be seen that the improvements in performance were steady and unspectacular.
The Germans, in addition to ordering Whitehead torpedoes in 1873, began building their own on the Whitehead principle. The firm of L. Schwartzkopf-later the Berliner Maschinenbau A.G.-began making excellent torpedoes in phosphor-bronze. The firm was soon exporting weapons to Russia, Japan and Spain. In 1885 Britain ordered 50 of these weapons because the output at home and at Fiume could not satisfy the demand. These weapons cost £450 each which was £120 more than the corresponding Fiume type (the 14 in. Mk. II).
The output at Whitehead's works was continually increasing and
Table 1 shows a sample of his products.
TABLE 1 Extract from the Whitehead Catalogue 1892
| Dia (in) | Length ft. in. | Material | Wt (lbs) | Cost |
| 15 | 18 9.5 | Steel | 904.5 | £350 |
| 15 | 18 9.5 | Bronze | 904.5 | £380 |
| 14 | 14 6 | Steel | 647 | £300 |
| 14 | 14 6 | Bronze | 647 | £325 |
| 14 | 12 3 | Steel | 498.5 | £290 |
| 14 | 12 3 | Bronze | 498.5 | £315 |
| 14 | 11 0 | Steel | 435 | £280 |
| 14 | 11 0 | Bronze | 435 | £300 |
In addition to the standard weapons many special types were produced to the specifications of foreign navies. In fact no less than 17 different types of weapon were produced at Fiume in 1884 and
Table 2 shows the countries to which weapons had been exported up to 1881.
TABLE 2 Sales of Whitehead torpedoes up to 1881
| Country | Type |
| 16 in | 15 in | 14 in |
| Argentine |
|
| 40 |
| Belgium |
| 40 |
|
| Denmark |
| 58 | 25 |
| Germany |
| 103 | 100 |
| England |
|
| 254 |
| France |
| 105 | 113 |
| Italy |
|
| 70 |
| Greece |
| 30 | 40 |
| Austria |
|
| 100 |
| Portugal |
|
| 50 |
| Russia | 25 | 215 | 10 |
| Others |
| 51 | 27 |
The 14 in. by 11 ft. weapon was built originally to the specification of the Russians who wanted a minimum speed output of 20 knots. This was achieved and all Whitehead weapons exceeded this speed from this time.
The speed improvements were made by increasing the inlet pressure to the engine (with consequent improvements to engine details) and a corresponding increase in air vessel pressure. By 1882 the vessels were being built to withstand at least 1,500 p.s.i. and Britain led the world in the construction of bronze pressure vessels.
Figures for weapon range were not reliable up to this time because range was not an important parameter. Ranging at Fiume was carried out from an underwater tube aimed at a net 400 yards distant. The maximum running distance was only measured when requested by a customer. After all, the chance of hitting a ship decreases rapidly with range because of the errors inherent in the weapon and the aiming process so that there was little point in firing a torpedo at a range greater than about 400 yards even if the weapon was capable of greater range. Thus the ranges tabulated at the end of Part 1 are nominal only but in many cases the maximum range is not very much greater than the quoted value.
At about this time the Italians built their own version of a Fiume torpedo but it ran at only 7 knots. Whitehead rebuilt it and it achieved 20 knots. As a result the Italians gave up building their own weapons and bought from Whitehead.
In external appearance the various weapons were very similar. The torpedoes were often built up with standard tail and nose sections but with different middle sections. These composite torpedoes each carried different mark numbers but were in fact very similar in performance. In 1883 a committee, set up to examine various aspects of torpedo design, carried out trials to test whether the nose shape had any effect on weapon speed. The pointed nose was assumed to cleave the water best but the great hydrodynamicist Dr. Froude advised that blunt head should show no disadvantage in speed performance and would allow much larger warheads to be carried.
Comparative trials were carried out using the Mk W Fiume and R.L. Mk XI torpedoes each fitted with blunt and pointed noses. The tests showed that the blunt-nosed torpedoes had a full knot advantage over the pointed nosed version. This meant that heavier warheads could be carried without loss of propulsive performance and the ultimate in blunt nose designs during this period appeared in 1909 with the American hemispherical heads. Fig. 7 shows the development of the torpedo shape to the form (in 1912) from which few departures took place in the following four decades.
FIG. 7. Evolution of the Blunt Nose Torpedo.
During the period covered above the United States had not taken advantage of the offers in 1869 and 1874 to manufacture Whitehead torpedoes under licence and followed an independent and generally unsuccessful development programme of her own. This, together with the extensive efforts in many countries to develop rivals to the supremacy of the
Whitehead torpedo will be described later.
Last Cold Compressed Air Whitehead Weapons
Whitehead torpedoes were being manufactured at a considerable rate during the last 15 years of the 19th century. From Fiume the Silurifico Whitehead was sending hundreds of weapons around the world and many more were being manufactured under licence in foreign countries or being simply pirated. A typical year's intake to the Royal Navy is listed on page 41 as an example of the activity around this period.
The German Schwartzkopf firm were manufacturing about 400 weapons annually which were sent to Spain, Italy, China and Britain (see
Table 4).
It was soon after the mid-1880s that torpedo performance began to improve. This was largely as a result of competition from improved gunnery. Indeed, in 1904 the battle of Tsushima was settled by gunfire at a range of 6,000 yards and no torpedo could at that time compete with such performance. The torpedo's saving grace was its ability to deliver with stealth an explosive charge to the most vulnerable part of a ship. Torpedo range was increased by the introduction of the l8in. Whitehead weapon in 1888 but not by a very great amount; the advantage being taken rather to increase the size of warhead.
Meanwhile at Woolwich torpedo performance improvements made the specially constructed canal too short and a new range was set up at
Horsea Island in 1888 and 10 years later the Bincleaves range was set up near Weymouth. In 1890 Whitehead opened his factory at Weymouth which survived until recently under the ownership of Vickers, Armstrong Ltd. In .1893 the Royal Navy decided to transfer the torpedo works at the Royal Laboratories to the
Royal Gun Factory (thus weapons became known as R.G.F. types) and as a result the Weymouth works did not get the British orders that were expected. Henceforth the Whitehead torpedoes produced at Weymouth were mostly sent for export to countries not able to manufacture their own. Similarly, Whitehead had opened a factory at St. Tropez at the same time as the Weymouth venture and this also exported to countries such as Brazil, Holland, Turkey and Greece. Some torpedoes from the Weymouth works did enter service with the Royal Navy especially during the 1914-18 war period. The last association of the works with the Royal Navy appears to have been in the early stages of the Mark 23 torpedo in the mid-1950s.
Whitehead always regarded his torpedoes as primarily for launching from underwater tubes. The Royal Navy however 'seems to have favoured above-water firing devices. Under water tubes can be placed either in the bow where the ramming effectiveness of the ship is weakened (ramming was a most popular means of naval warfare in the 1 870s) or they can be placed across the ship for broadside shots. In the latter position the torpedo experiences a strong twisting force as it emerges due to the water flow along the ship. A device for overcoming this effect was invented by Capt. A. K. Wilson, V.C. and consisted of a guide bar projecting from the ship along which the emerging weapon slid until free of the disturbing effect of the ship's motion. Another device ejected a tube with the torpedo for a distance of several feet such that the water flow forces were taken by the tube and not the weapon.
These devices were adopted by the British but were not generally popular. The first above water launching was made by sliding a l4in. weapon off a mess table out through a porthole and, having thus proved the feasibility of the scheme, several methods were evolved for launching weapons from a ship's deck. Most of the early methods consisted of a simple frame for holding the torpedo over the water and releasing it in approximately the right direction. Light torpedo boats used a frame which was lowered about 2ft. into the water for launching.
The tube working on the pea shooter principle was invented in about 1880. The weapons were ejected by compressed air but within a few years the propelling gas was generated by slowburning gunpowder in granular form. This remained the method of tube launch for many decades; indeed the present deck-mounted tubes work on exactly the same scheme but with different propelling cartridges.
The British method of discharging torpedoes from above the waterline was viewed with some concern by Whitehead. His son-in-law and partner, Count George Hoyo's, reported after a visit to Britain that "such delicate weapons are not meant to be fired like shot from a gun" but the weapons 'seemed to tolerate their rough treatment for in 1879 there were already 33 British warships fitted with launching equipment.
Introduction of the Gyroscope
In 1895 came the first significant improvement to the torpedo since its invention. Whitehead introduced the gyroscope for azimuth control using the type invented by an Austrian, Ludwig Obry. In this device a 1.75 lb. wheel some 3in. in diameter was held in gimbals with its axis along that of the torpedo. The wheel was spun up to maximum speed 2,400 r.p.m. by means of a pretensioned spring. The wheel reached this speed before the weapon left the tube so that the torpedo followed the aimed-for track in the water irrespective of the impulsive forces acting on hitting the water. This greatly improved the overall accuracy of firing and with the new device fitted it was possible to fire to an accuracy of ~ thus enabling a beam-on target to be hit at a range of about 7,000 yards-except that torpedoes at that time had ranges not exceeding 1,000 yards.
This clearly provided a considerable impetus for torpedo designers to increase performance. The original Obry gyroscope wheel only contained a maximum of 20ft. - lbs. of energy. This had the effect of allowing the gyro to topple after an inconveniently short time of running. The toppling was induced by the fact that the gyroscope gimbals were required to directly operate a rudder servo control. Whitehead soon introduced an intermediate servo however which greatly reduced the forces acting on the gimbals and the way was then opened up for long range weapons.
The version of the Obry gyroscope supplied to the United States was provided with an angling gear which enabled the weapon to change course after firing, thus giving greater flexibility in the firing procedure. This refinement was introduced into the Royal Navy in 1900.
The turn of the century saw a radical change in torpedo design with the introduction of the heated, or steam torpedo. This is therefore an opportune time to study the torpedo development of nations, such as the United States, who did not adopt the Whitehead compressed air method of propulsion.
Departures from Whitehead Principles
The Torpedo Test Station was set up in 1870 at Rhode Island, U.S.A. to work on
spar torpedoes but in 1871 an automobile torpedo was built, Fig. g this was built on the supposed lines of the Whitehead weapons and indeed the propulsive performance was similar,
i.e. 7 knots to a range of 300 yards. The warhead was 70 to 90 lbs. of dynamite or guncotton. Here the similarity to the White-head torpedo ends for the American version refused to run a straight course. This is not surprising in view of the minimal control surface area provided. Another weapon was built in 1874 but this was no more successful. The air vessel was made of bronze in the latter case because no American firm would undertake to make a steel vessel of sufficient strength. The British were masters of the forging and rolling art for pressure vessels at this time. The Japanese had many failures in this respect and eventually bought their pressure vessels from England.
FIG. 8. First United States Automobile Torpedo.
Having failed to produce a working automobile torpedo and having turned down two offers of the Whitehead plans (one offer being quite unofficial from an ex-foreman from Woolwich-industrial sabotage at an early age !) the Torpedo Test Station set about building under the inventive eye of J. L. Lay, an officer in the U.S. Navy, a series of strange and generally unsuccessful weapons.
Most of the weapons floated and thus did not have the ability to vary the striking depth at the enemy ship. The Lay torpedoes floated with only a few inches of hull showing and were controlled by an operator by means of electrical impulses sent down a wire. The power unit was a gas engine driven by compressed carbon dioxide and the steering impulses transmitted down the wire operated electromagnetic relays on the rudder. The position of the weapon was indicated by two flags or discs. Fig. 9 shows an early form of the Lay Torpedo as built in the 1870s. A later form used liquefied C02 as the power source with the liquid warmed in pipes external to the weapon. Still later we find the Lay-Haight weapon driven by gas generated by the action of sulphuric acid on lime. The later weapons had their propeller near the forward end of the hull partially recessed to avoid damage. It also avoided efficient propulsion!
FIG. 9. Lay Dirigible Weapon.
These weapons were never really successful on account of their unreliability and vulnerability to gunfire. In a trial carried out off the British coast for the Royal Navy the Lay weapon heeled over badly so that the propeller was only half under the surface.
Two Lay torpedoes were sold to the Peruvian Government for use in the war against Chile. In 1879 a Lay weapon was fired from the Peruvian ironclad
Huascar at a Chilean ship. Half-way to the target the weapon turned around and "hurtled" at 15 knots back at the mother ship despite the frantic knob twiddling of the operator. The ship was saved by the heroic action of a ship's officer who swam out to intercept the weapon and deflect it. The relieved captain promptly took the two weapons to a local graveyard where they were buried only to be later exhumed by the Chilean rebels!
The performances of the Lay torpedo together with several other weapons of this period are tabulated at
Table 5.
The vulnerability of these weapons was overcome in the 'Patrick ' and 'Wood-Haight' 'torpedoes by suspending them beneath unsinkable floats. These floats were either wood or thin copper sheet cylinders containing water-proofed cotton waste. The floats could be shot again and again without sufficient buoyancy being lost to sink the weapon. The propulsion was by compressed carbon dioxide gas expanded through a gas engine-usually a three-cylinder Brotherhood type, similar to the version used extensively by Whitehead.
The electric torpedo made its appearance in about 1873 with the Ericsson which was propelled by sending power down a cable unreeled from the weapon (Ericsson was the builder of 'Novelty', one of the locomotives tested at the Rainhill competition in 1829 at which Stephenson's 'Rocket' was the winner.) A direct development of the Ericsson torpedo was the Sims-Edison which was similarly powered down a trailing wire. A speed of 10 knots was attained using a Siemens motor drawing 30 amps at 600 volts. Several versions of this weapon appeared, all carried under a large float and very similar in external appearance to the weapon of Fig. 10, and the last version built in 1889 carried a 4001b. warhead to a range of over two miles.
FIG. 10.
Nordenfelt Wire-Guided Electric Torpedo.
The
Nordenfelt torpedo, illustrated in Fig. 10, was invented by the great Swedish engineer who also produced the first really successful submarine. Motive power was from a vast stack of batteries, the early version having 108 storage cells which produced 18 S.H.P. Guidance was by means of electrical impulses transmitted down a wire paid out from the weapon. A British intelligence report of the period described the early weapon as being supported by a wooden float and carrying one mile of guidance wire. The weapon described by Sleeman and illustrated in Fig. 10 was said to have been buoyant and held down by the heavy fins. It is difficult to see how this weapon could have remained upright. The sloping edge to the fin was supposed to assist the weapon to pass under
torpedo nets. This weapon, the forerunner of the present generation of wire-guided electric torpedoes, achieved 16 knots to a range (for the later version) of two and a half miles.
Superheated steam was a popular means of propulsion in the 1 880s and the American 'Hall' torpedo was typical. Water at 5500F and under high pressure was fed directly from the boiler of the
torpedoboat. Evaporation of the water under reduced pressure provided a propulsive performance comparable with con-temporary Whitehead models. None of these steam torpedoes reached the production stage. largely because of the lengthy preparation time required. Hall's weapon had a strange roll control system based on a transverse mercury-filled U-tube. Any rolling action of the weapon caused wings to be pushed in and out under the action of the mercury. The wings were angled to provide lift in such a fashion that the weapon maintained, in theory at least, an even keel. Another superheated water weapon, the Paulson, was kept on a straight heading by a mariner's compass in the nose. Electrical contacts on the compass could be set just before launch and the weapon followed that setting after launch.
FIG 11 Cunningham's Rocket Torpedo.
Rocket propulsion has been often considered even up to the present time One of the first automobile torpedoes built after the Whitehead model made its appearance was rocket propelled Both the Weeks and the Ericsson rocket achieved about 40 to 60 knots to a range of 100 yards. Lt. F. M. Barber of the Naval Torpedo Station, Rhode Island, produced an underwater rocket in 1873. This was 7 ft. long by 1 ft. diameter and weighed 287 lbs. The warhead was 48 lbs. of gunpowder and the 51 lbs. of rocket fuel were stored inside a cast iron tube wrapped in asbestos and having an outer casing of oak!
Mr. Cunningham, an American shoemaker, built rocket torpedoes and once celebrated the 4th July by setting off one of his torpedoes up the town's main street. It shot off at high speed scaring old ladies and horses and finally came to rest in the butcher's shop where it set fire to the icebox.
The
Berdan (sometimes called the Borden) was a rocket propelled floating torpedo which towed another small weapon. Fig. 12 shows how the rocket ower was converted to rotary power by means of a turbine acting on a set of propellers. When the
Berdan struck the
torpedo nets surrounding a ship the slackening of the towline caused the small weapon to go into a programmed dive under the nets and strike the ship under the keel in theory that is ! British intelligence reports of trials carried out before the Turkish Navy indicate that this weapon was not a success.
FIG. 12. Berdan Torpedo.
Rockets were not the only alternative propulsion systems to challenge the conventional propeller drive. One torpedo invented during this period was propelled by an umbrella4ike contraption at the rear. This was operated by an oscillating shaft which opened and shut the "umbrella" and so propelled the vehicle rather in the fashion of a frog's foot! We must not be too scornful of such outrageous devices because nature has settled on that system for frogs after many millions of years R & D work. During the last war the Germans devised a torpedo propelled by a flapping wing. This was claimed to be at least as efficient as a conventional propeller and much quieter. Once again we can note that nature has used this method for some time without complaint. The advantages of blunt noses on torpedoes might also have been realised earlier if the first torpedoists had studied the salmon.
Only two torpedoes, apart from the White-head patterns, went into successful quantity production before the turn of the century. (The Lay weapon was exported to Russia for harbour defence work but only in small quantities). The
Brennan torpedo was invented by an Australian watchmaker and was driven by pulling two 18 gauge piano wires out of the weapon. This was achieved by a steam winch mounted on the shore. The use of this torpedo from ships was ruled out by the need for a stable winch platform. The wires were unreeled from two drums inside the weapon and these directly drove the
contrarotating propellers. Steering was achieved by varying the relative tension of the wires. This caused the weapon to heel over and a compensating pendulum applied steering control. Fig. 13 shows a later version of this weapon where the drums were on a common longitudinal axis. A depth control similar to that used by Whitehead was installed. The performance of the Brennan was 20 knots to a range of 3,000 yards-this being considerably better than the contemporary Whitehead weapon-and the range was only limited by the length of wire carried. The weapon was used exclusively for coastal defence by the Royal Engineers over a 20 years period around the turn of the century. The huge Brotherhood winches were installed in concrete blockhouses and the 'torpedoes were run down to the water on rails. The derelict remains of a
Brennan torpedo station have been discovered on the Thames estuary.
FIG. 13. The Brennan Torpedo.
A scandal blew up over the adoption of this torpedo when the Government paid Brennan no less than £110,000 for his invention and paid him a vast salary to act as production chief. Compare this sum with the miserable £15,000 paid for the manufacturing rights of the much more worthy Whitehead weapon only 15 years previous.
Maxim, brother of the famous gun manufacturer, produced in the United States a wire-powered torpedo suspiciously similar to the Brennan except in the detail of depth keeping. The Maxim torpedo actually pumped water into or out of a ballast tank. Such fanciful devices are not confined to the last century. In 1944 a torpedo was built in Britain that varied its depth by pushing the main battery to and fro to alter the position of the centre of gravity.
Finally we will consider the
Howell torpedo which was the mainstay of the United States Navy for 20 years up to about 1895 and was a serious contender to the supremacy of the Whitehead torpedo outside the United States. Fig. 14 shows the appearance of the weapon and Fig. 15 shows the internal construction. The propulsive power was derived from a heavy flywheel and transmitted to twin propellers. The weapon was ship-launched from a tube and the flywheel was spun just prior to launching by a steam winch external to the launching tube.
FIG. 14. The Howell Flywheel Torpedo (1892).
FIG. 15.
Howell Torpedo.
A wheel speed of 12,000 r.p.m. was obtained in the later versions of the weapon and with a wheel weighing 130 lbs. this gave a weapon performance of 30 knots to 800 yards with a decreasing speed for a further 400 yards. This was comparable with the Whitehead weapons of the same period (see
Table 5). This relatively good performance combined with simplicity of construction and operation resulted in the Whitehead torpedo not making its appearance in the United States until 1892.
The Howell torpedo had three advantages over the Whitehead apart from simplicity. The weapon left no track, it did not vary its trim and. more important, it kept to a straight course. This latter was achieved by using the gyroscopic action of flywheel. Because the wheel axis was transverse any departure of the weapon from a straight line caused the weapon to heel over. This was detected by a transverse mounted pendulum which was directly connected to rudders which produced a correction to the course and hence a righting torque. This was in fact the first application of the gyroscope to torpedoes. When the Obry gyroscope was used in Whitehead torpedoes in 1895 Howell started a legal battle over patent rights.
The above weapons were departures from the Whitehead compressed air principle but one weapon, again the brainchild of Ericsson, eliminated the heavy air vessel by supplying compressed air through an 800 ft. hose. The drag on the hose greatly slowed down the weapon however.
TABLE 3 Selection of cold air torpedoes
| Type | Year | Weight lbs | Warhead Weight lbs | Speed Kts | Range yards | Remarks |
| 14 in Fiume | 1866 | 265 | 18 | 7 | 200 | Original model |
| 14 in Fiume | 1868 | 346 | 40 | 7 | 200 | Model demonstrated to Austrians |
| 16 in Fiume | 1868 | 650 | 67 | 7? | 600 | Model demonstrated to Austrians |
| 14 in RL Mk1 | 1875 | 530 | 26 | 18 | 600 | First British make |
| 15 in Fiume | 1882 | 904 | 94 | 21 | 800 |
|
| 14 in Fiume | 1882 | 498 | ? | 24 | 400 | Built for Russians |
| 14 in Fiume | 1883 | ? | 117 | 20 | 800 | Largest 14in warhead |
| 14 in German | 1883 | 581 | 44 | 21 | 650 | `Schwartzkopf' |
| 12 in Fiume | 1883 | 272 | 33 | 21 | 200 |
|
| 14 in RL MkV | 1886 | 660 | 58 | 24 | 600 |
|
| 18 in Fiume | 1890 | 1236 | 198 | 30 | 800 | First 18in in Royal Navy |
| 18 in Fiume | 1906 | 1609 | 220 | 35 | 1000 | Last `Cold compressed air' in Royal Navy |
TABLE 4 Royal Navy Intake 1886
| 14 in RL MkV | 200 |
|
| 14 in Fiume Mk IV | 200 |
|
| 14in x 11ft Fiume | 2 | Experimental |
| 12in Fiume | 10 | Experimental |
| 14in German | 50 |
|
| 14in RL MKV | 2 | Built privately |
TABLE 5 Torpedo Performance
| Type | Year | Weight lbs | Warhead Weight lbs | Speed Kts | Range yards | Remarks |
| 14in Fiume | 1882 | 498 | ? | 24 | 400 | Typical Whitehead |
| 18in Fiume | 1890 | 1236 | 198 | 30 | 800 | Royal Navy's First 18 in |
| 18in Fiume | 1906 | 1609 | 220 | 35 | 1000 | Last cold air weapon |
Types other than compressed air |
| 18in Lay | 1880 | 2500 | 200 | 16 | 4000 | Compressed CO2 |
| 22in Patrick | 1886 | 6000 | 200 | 21 | 2000 | Similar to Lay |
| 16in Ericsson | 1880 | 1500 | 300 | 61 | 100 | Rocket |
| 29in Nordenfelt | 1888 | 5000 | 300 | 16 | 4000 | Wire-guided battery driven |
| 14in Howell | 1894 | 520 | 100 | 26 | 400 | Flywheel drive |
| 18in Howell | 1895 | 700 | 180 | 30 | 1200 | Flywheel drive |
| 21in Brennan | 1885 | ? | 200 | 20 | 3000 | Wire powered |
Having taken the technical development of the torpedo up to the turn of the century we will finish this section with a look at the aggressive use of the weapon. The first sinking by a torpedo was during the Chilean revolutionary war. Two Birkenhead-built torpedo boats attacked the
Blanco Encalada on the night of April 23rd, 1891. The first boat,
Almirante Conte fired three Whiteheads at the ironclad but these all missed. The second torpedo boat, the
Almirante Lynch fired another salvo of three weapons and one hit. The effect of the 58 lb. of guncotton in the 14 in. weapon was to blow a hole 15 ft. by 7 ft. below the waterline. The ship sank immediately with the loss of 180 officers and men. The ship had left her torpedo nets at port and the water-tight doors were not closed. One consequence of the explosion was the ejection of the Captain, Don Luis Goni, up a ventilation shaft and into the sea where he was later seen swimming ashore with one arm around the ship's mascot, a tame llama. The animal was then taken as mascot onboard H.M.S.
Warspite until it was sent to the London Zoo in disgrace for eating the epaulettes off an Admiral's dress uniform!
The Chinese had little success with their Schwartzkopf weapons in the war of 1894 largely because theirs were fired at very long ranges. Local fishermen recovered them from the beaches and sold them back to the Chinese for 100 dollars each. Such inefficiency is only to be expected from officers who pawned their ship's guns in the ports!
The Heated Torpedo
With increasing air pressures it was found that freezing could occur on the expansion phase of the standard
compressed air engine and as a cure heating was introduced. This produced spectacular results apparently to the surprise of the designers. It is not clear whether the first effective
heating system was introduced by Britain or United States. The earliest form was the "Elswick” heater as patented by Sir W. G. Armstrong, Whitworth and Company in 1904. Fuel was sprayed into the air vessel of a conventional weapon and ignited. The device was demonstrated in an 18 in. Fiume Mk. III at Bincleaves in 1905 before a distinguished audience of British and Japanese experts. The weapon speed was nine knots more than for the unheated version. The system had the disadvantage of badly sooting the air vessel however and large temperature excursions could sometimes occur.
The Whitehead heater system, introduced two years after Robert Whitehead's death in 1905, mixed the fuel and air after the pressure reducer so that only a small volume was exposed to the heat of combustion. Even so the combustion chamber had to be cooled and for this reason water was swirled around to the walls. The vaporisation of the water greatly added to the energy available for propulsion. These systems became known as the "dry heater" and "wet heater" respectively. Although also known as "steam" torpedoes it can be seen that these wet heater weapons were still primarily hot air driven with the steam providing extra energy.
The engines then in use had to be modified to cope with inlet temperatures of the order of I ,0000F by changing the valve arrangement and adding a cylinder to give a four-cylinder radial engine capable of 180 H.P. as shown in Fig. 16.
FIG. 16. Four-Cylinder Brotherhood Radial Engine as used by Whitehead.
Fig. 17 shows the layout of the R.G.F. wet heater system and it can be seen that the water supply pressure is used to force the fuel into the combustion pot. Thus, if the water feed should fail for any reason, the fuel would be automatically cut off, thus preventing the combustion pot from burning out. In fact, a rather simpler system was invented in 1908 by Engineer Lieut. Hardcastle and became known as the R.G.F. heater.
FIG. 17. R.G.F. Heater System.
The United States had taken up the manufacturing rights for the Whitehead cold compressed air weapons in 1892 and Fig. 18 shows the Mark I weapon produced in that year. The Mark II and III weapons embodied slight improvements but the Mark V was the first to carry a heater. Although the British had experimented with a Parsons turbine as early as 1899 and later with a Curtis type the results were not encouraging and the four-cylinder engine remained in vogue with British torpedoists for many years. Mr. F. Leavitt, who worked for the E. W. Bliss concern where the Whitehead weapons were made under licence, regarded the Brotherhood engines as "corny" and set about building a Curtis-driven weapon which became known as the Bliss-Leavitt Mark I. This was accepted into the U.S. Navy in November
1905. The propulsion was by dry heater using
alcohol as fuel without water diluent. This latter was acceptable on account of the relatively low calorific content of alcohol. From this point in time until the introduction of the electric torpedo during the last war the U.S. Navy have stood by the turbine and the British by the
reciprocating engine.
FIG. 18. 18 in Fiume type built in USA (1892).
The gearing was to be a source of much concern in later years when the noise of torpedoes became an important feature of torpedo detection and it was found that the tail gearing was the primary source of high frequency noise. The need for a relatively low inlet temperature to the turbine also reduced efficiency due to the use of either a low performance fuel or water injection. The requirement to carry a diluent (and hence reduce the payload of the weapon, was overcome during the last war when the Japanese injected seawater directly into their turbines. This policy was not universally popular however. The French in fact were experimenting with a seawater diluent turbine engine in 1913 with which it was claimed a 50 knot torpedo would be powered. This does not appear to have materialised and the French continued to rely on piston engines at least for another decade.
In the period from the introduction of the heated torpedo until the Great War many attempts were made to improve weapon performance but few of these experiments reached service in time for the war. A contrarotating direct drive turbine was developed in Britain by two midshipmen named Montagu and Larcom but the Board of Enquiry rejected the idea and this marked the end of turbine drive in British weapons. Further experiments were carried out at R.A.E. Famborough after the First World War but with no better success.
FIG. 19. US Bliss-Leavitt, Mark 3 (1911).
The
reciprocating engine was, by the outbreak of war, well established and although the Whitehead concern had produced a huge two-cylinder engine just prior to the war it never entered service during that period. The problems of improving performance were setting designers thinking of ways to eliminate the very heavy air pressure vessel which often accounted for one third of the weapon weight.
The use of enriched air and even pure oxygen had been considered at an early date but rejected on account of the capricious nature of these gases. The British 'tried adding Ammonium Nitrate to the torpedo's "drinking water". This chemical broke down into water and Nitrous Oxide (N20), this latter being an oxidant. Although some propulsive improvements were found these were not sufficient to warrant building service weapons.
As part of this search for greater
propulsive efficiency, the three-bladed propeller was introduced in 1893 and the four-bladed by 1897. Further increases did not occur until recent times. Propeller design was empirical at the turn of the century because the necessary theory had not then been developed but even so quite good designs were found. Indeed, a speed difference of only ~ knot was considered significant. Fig. 20 shows the curiously curved blades adopted around the period of the First World War. Good examples of German l9.7 in. weapons with these blades can be seen at the Armoury Museum, Valletta. The purpose of the blades was to assist the torpedo to slip through holes in anti-torpedo netting used extensively for ship protection.
FIG. 20. Tail of 19.7 German Torpedo (1917). Note curved Propellers.
These nets were arranged to be swung out on booms at short notice and were popular for several decades. Fig. 21 shows two torpedoes caught in nets around H.M.S.
Diamond during practice shots in the pre-First War period. Several counters to the nets were devised, many of them by the Whitehead firm. Fig. 22 shows one device fitted to weapon noses designed to force the net apart. Other devices included explosive charges in the nose which fired a circular cutter into the net. The torpedo then slipped through the hole so produced.
FIG. 21. Net Protection of HMS Diamond Two Torpedoes caught at 8.5 knots.
FIG. 22. Experimental net piercing nose cap (1914).
Nets became unpopular for battle engagements because of the slow speed enforced on the ship by their use. Eventually they were restricted to the protection of ships in harbour; a use which survived through the last war.
The first 21 in. torpedo, the forerunner of the present submarine weapon, appeared in 1908 as the R.G.F. Mk. I having a range of 3,500 yards and a speed of 45 knots. The corresponding United States weapon was the Bliss-Leavitt Mk. VIII which appeared in 1913. The 21 in. weapons were by no means the largest diameter "conventional" torpedoes. A 26 in. diameter weapon had been produced in 1900 and Whitehead built a 27.5 in. weapon for the Japanese Navy. These were experimental weapons however and were not successful on account of dynamic instabilities resulting from their relative shortness.
Around the turn of the century the American firm of Bliss-Leavitt introduced the air-blast gyroscope whereby the wheel was run up to a speed of 10,000 r.p.m. in only 0~35 seconds from firing. This gyro provided adequate control over the weapon from firing to impact despite the long ranges now being obtained (see
Table 6).
TABLE 6 Comparison of weapons in use at the start of World War 1
| Type | Year | Weight lbs | Warhead Weight lbs | Speed Kts | Range yards | Remarks |
| 18 in Fiume | 1908 | 1609 | 253 | 42 34 28 | 1090 2190 4370 | Dry heater |
| 18 in RGF Mk VII | 1908 | 1553 | 200 | 30 41 | 5500 3000 | Warhead increased to 320lb in 1917 |
| 18 in RGF Mk VI | 1909 | 1490 | 200 | 29 | 6000 | Cold type converted |
| 18 in Fiume | 1911 | 1620 | 253 | 42 27 | 1090 6560 | Wet heater |
| 18 in Fiume | 1911 | 1743 | 220 | 44 31 | 2190 6560 | New 2-cylinder engine |
| 21 in Weymouth Mk II | 1914 | 2794 | 225 | 29 | 10000 |
|
This type of gyroscope remained virtually unchanged until the introduction of the air-blast maintained wheels of the last war.
British torpedoes in the first two decades of this century were produced at the Royal Naval Torpedo Factory (opened at Greenock in 1910), the
Royal Gun Factory at Woolwich and external purchases from the Weymouth and Fiume factories of Robert Whitehead. The main production prior to the war was the R.G.F. Mk. VII and the Whitehead Weymouth Mk. I, both 18 in. weapons as was the R.N.T.F. Mk. VIII which was a submarine4aunched weapon and the first type to be produced at Greenock.
The Weymouth works produced their first 21 in. torpedo in 1909 but only two experimental models were built and after unsuccessful trials they were scrapped in favour of the much more successful Weymouth Mk. II which was sold extensively abroad and to the Royal Navy. Just before the war Whitehead's empire came under the strong influence of Vickers, Armstrong Ltd. This influence was to dominate the British Whitehead Factory until after the Second World War when the independent torpedo production ceased after a series of abortive ventures.
By the outbreak of war in 1914 most of the old "cold air" torpedoes had been converted and a new type of torpedo known as a pattern runner was invented by Lieut. F. H. Sand-ford. This weapon could be sent to run a preset distance and then zig-zag back and forth along a given track. This made the chance of hitting a ship much greater when the speed of the target was not accurately known.
Practice with torpedoes in the Royal Navy was carried out at the rate of 8,000 test shots per year with a hitting rate of 98%. It must be admitted that the test was not nearly as severe as one would expect to experience in wartime. The firing of torpedoes was by 1914 the main means of attack by submarines. A highly embellished account of a trip in a submarine is given in Jane's book
Torpedoes and Torpedo Warfare published just before the turn of the century. The reader is left in a claustrophobic state of mind after only a few pages but it is interesting to note the rapid and parallel development of the submarine and torpedo and the way they eventually became essential to each other's effectiveness as a fighting system.
Before finishing it is perhaps worth recalling the incident at Simonstown Naval Base when a mechanic stripped down a torpedo believing it to have been run and exhausted. In fact the air vessel was fully charged to over 2,000 p.s.i. As the man unscrewed the air vessel drain plug the screw stripped the last three threads and the complete torpedo shot off, literally, like a rocket. It hit the far wall of the workshop at roof level and bounced 30 feet back to land as a crumpled mess of metal at the mechanic's feet. The man suffered only shock and presumably a desire to be more careful in future! In the same year an 18 in. weapon broke the then world high jump record for torpedoes by leaping 40 feet into the air as a result of an elevator malfunction at over 45 knots! This record has been broken several times in more recent times.
Early Military Areal robot & Drones
Early US Target Drones
The first important use of robot aircraft was as targets for anti-aircraft gunnery training. Target "drones" were introduced into wide-scale service for this application during World War II, forming a basis for their widespread use after the war. This chapter provides a survey of American target drones of World War II and the postwar period.
* The first pilotless aircraft, intended for use as "aerial torpedoes" or what we would now call "cruise missiles", were built during and shortly after World War I, and led to the development of radio-controlled (RC) pilotless target aircraft in Britain and the US in the 1930s. In 1931, the British developed the Fairey "Queen" radio-controlled target from the
Fairey IIIF floatplane, building a batch of three, and in 1935 followed up this experiment by producing larger numbers of another RC target, the "DH.82B Queen Bee", derived from the de Havilland Tiger Moth biplane trainer. Through some convoluted path, the name of "Queen Bee" is said to have led to the use of the term "drone" for remote-controlled aircraft.
The US Navy began experimenting with
radio-controlled aircraft during the 1930s as well, resulting in the Curtiss "N2C-2" drone in 1937. By the outbreak of World War II, obsolescent aircraft were being put into service as target drones as the "A-series" targets. Since the "A" code would be also assigned to "Attack" aircraft, later "full-sized" targets would be given the "PQ" designation. During the war the US Army Air Forces (USAAF) would acquire hundreds of Culver "PQ-8" target drones, which were radio-controlled versions of the tidy little
Culver Cadet two-seat civil sportplane, and thousands of the improved Culver "PQ-14" derivative of the PQ-8, with such refinements such as retractable landing gear. The US also used RC aircraft, including modified B-17 and B-24 bombers, in combat on a small scale during World War II as aerial torpedoes, though with no great success.
The first large-scale production, purpose-built drone was the product of an interesting fellow named Reginald Denny, born Reginald Leigh Deymore in Britain. He served with the British Royal Flying Corps during World War I, and after the war emigrated to the United States to seek his fortunes in Hollywood as an actor. Denny played a lead role in a number of his earlier films, generally as a comedic Englishman, and later had reasonably steady work as a supporting actor in dozens of movies, including a screen version of ANNA KARENINA with Greta Garbo and the Frank Sinatra "caper" movie ASSAULT ON A QUEEN. Between acting jobs, he pursued his interest in RC
model aircraft, opening a model-airplane shop on Hollywood Boulevard in the early 1930s. The shop evolved into the "Radioplane" company.
Denny believed that low-cost RC aircraft would be very useful for training anti-aircraft gunners, and in 1935 he demonstrated a prototype
target drone, the "RP-1", to the US Army. This led to demonstration of an "RP-2" in 1938, with flights of the "RP-3" and "RP-4" in 1939. The Army placed an order for 53 RP-4s, designating them the "OQ-1", the "OQ" meaning a "subscale target". This small order led to a much bigger 1941 order from the US Army for the company's similar "RP-5", which became the US Army "OQ-2". The US Navy also bought the drone, designating it "
Target Drone Denny 1 (TDD-1)". Thousands were built, manufactured in a plant at the Van Nuys Airport in the Los Angeles metropolitan area.
The OQ-2 was a simple aircraft, powered by a two-cylinder two-cycle engine, providing 4.5 kW (6 HP) and driving contra-rotating propellers. It really looked like nothing more than a plain and simple, if big, hobbyist RC flying model aircraft. The RC control system was built by Bendix.
RADIOPLANE OQ-2:
_____________________ _________________ _______________________
spec metric english
_____________________ _________________ _______________________
wingspan 3.73 meters 12 feet 3 inches
length 2.65 meters 8 feet 8 inches
takeoff weight 47.2 kilograms 104 pounds
maximum speed 137 KPH 85 MPH / 74 KT
service ceiling 2,440 meters 8,000 feet
endurance 70 minutes
launch scheme Conventional runway takeoff.
recovery scheme Parachute or runway landing.
guidance system Radio control.
_____________________ _________________ _______________________
The OQ-2 led to a series of similar but improved variants, with the "OQ-3 / TDD-2" and "OQ-14 / TDD-3" produced in quantity. It should be emphasized that many other targets were built by Radioplane and a number of other companies during the war, most of which never got beyond prototype stage, which might be suspected by the gaps in the designation sequence between "OQ-3" and "OQ-14". * Although small piston engines were the normal powerplant for targets in this era, there was something of a fad for pulsejet propulsion as well, though it doesn't appear that the US military ever acquired any pulsejet-powered targets in more than modest numbers. McDonnell built a pulsejet-powered target, the "T2D2-1 Katydid", later the "KDD-1" and then "KDH-1". It was an air-launched cigar-shaped machine with a straight mid-mounted wing, and a vee tail straddling the pulsejet engine. The Katydid was developed in mid-war and a small number were put into service with the US Navy.
After the war, the Navy obtained small numbers of another pulsejet-powered target, the "KD2C Skeet" series, built by Curtiss. It was another cigar-shaped machine, with the pulsejet in the fuselage and intake in the nose. It featured straight, low-mounted wings with tip tanks, and a triple-fin tail.
BACK_TO_TOP
* In the postwar period, Radioplane followed up the success of the OQ-2 series with another very successful series of much improved piston-powered target drones, what would eventually be called the "Basic Training Target (BTT)" family. The BTTs remained in service for the rest of the century.
The BTT family began life in the late 1940s, evolving through a series of refinements with the US Army designations of "OQ-19A" through "OQ-19D", and the US Navy name of "Quail" with designations of "KD2R-1" through "KD2R-5". Early models had a metal fuselage and wooden wings, but production standardized on an all-metal aircraft. Radioplane developed an experimental "XQ-10" variant that was mostly made of plastic, but though evaluation went well, it wasn't any major improvement over existing technology and it did not go into production.
In 1963, when the US military adopted a standardized designation system, the surviving US Army BTT variants became "MQM-33s" and the Navy KD2R-1, the only member of the family still in Navy service, became the "MQM-36 Shelduck". The "BTT" designation wasn't created until the 1980s, but is used here as a convenient way to resolve the tangle of designations.
The MQM-36 was the most highly evolved of the BTT family, but retained the same general configuration as the other members. It was larger and more businesslike than the first-generation OQ-2A series, and was powered by a more powerful flat-four four-stroke McCulloch piston engine with 71.2 kW (95 HP). The MQM-36 could carry radar enhancement devices on its wingtips.
RADIOPLANE MQM-36 SHELDUCK:
_____________________ _________________ _______________________
spec metric english
_____________________ _________________ _______________________
wingspan 3.5 meters 11 feet 6 inches
length 3.85 meters 12 feet 8 inches
height 0.76 meters 2 feet 6 inches
empty weight 123 kilograms 271 pounds
launch weight 163 kilograms 360 pounds
maximum speed 370 KPH 230 MPH / 200 KT
service ceiling 7,000 meters 23,000 feet
endurance 1 hour
launch scheme RATO booster or bungee catapult.
recovery scheme Parachute.
guidance system Radio control.
_____________________ _________________ _______________________
Over 73,000 BTT targets were built in all, and the type was used by at least 18 nations. Some may still be lingering in service. * A variant of the BTT named the "MQM-57 Falconer" was built for battlefield reconnaissance, with first flight in 1955. The Falconer was similar in appearance to the Shelduck, but had a slightly longer and definitely stockier fuselage. It had an autopilot system with radio-control backup, and could carry cameras, as well as illumination flares for night reconnaissance. Equipment was loaded through a hump in the back between the wings.
Although it only had an endurance of a little more than a half-hour, making it of limited use, about 1,500 Falconers were built and the type apparently was used internationally with several different military forces, remaining in service into the 1970s. There were other BTT derivatives that didn't have much impact, one of the most interesting being the "NV-101" of the early 1960s, which was effectively an autogyro variant. Exactly why it was built remains unclear, it may have possibly been intended to simulate helicopter targets, but it is certainly clear that nothing came of it.
Radioplane was bought out by Northrop in 1952 to become the Northrop Ventura Division, though it appears that the "Radioplane" name lingered on for a while. Reginald Denny died in 1967 at age 75, after what sounds like an interesting and profitable dual career in the movie and aviation industries.
* Just to confuse matters, the US military acquired a number of other drones similar in many ways to the Radioplane drones. The Globe company built a series of targets, beginning with the piston-powered "KDG Snipe" of 1946, which evolved through the "KD2G" and "KD5G" pulsejet-powered targets and the "KD3G" and "KD4G" piston-powered targets, to the "KD6G" series of piston powered targets. The KD6G series appears to have been the only one of the Globe targets to be built in substantial numbers. It was similar in size and configuration to the BTT series, but had a twin-fin tail. It was redesignated "MQM-40" in the early 1960s, by which time it was generally out of service.
In the late 1950s, along with the Falconer, the US Army acquired another reconnaissance drone, the Aerojet-General "MQM-58 Overseer". It had a similar configuration to the Falconer, but featured a vee tail and was about twice as heavy. It does not appear to have been built in large quantities, and may have never been much more than an experimental platform to evaluate more sophisticated reconnaissance sensors than could be carried by the Falconer.
* The Northrop Ventura division went on to build improved jet and rocket propelled targets. In the late 1940s, the company developed a set of prototypes of the "Q-1" target series, which used pulsejet or small turbojet engines. Although the Q-1 series was not put into production as a target, it did evolve into the USAF "RP-54D / XB-67 / XGAM-67 Crossbow"
anti-radar missile, which was first flown in 1956. It was also considered as a platform for reconnaissance, electronic countermeasures, and decoy roles.
The Crossbow had a cigar-shaped fuselage, straight wings, a straight twin-fin tail, and an engine inlet under the belly. It was powered by a Continental
J69 turbojet, which was a French Turbomeca Marbore II engine built in the US under license, with 4.41 kN (450 kgp / 1,000 lbf) thrust. Two Crossbows could be carried by a
Boeing B-50 Superfortress bomber, while four Crossbows could be carried by a Boeing B-47 Stratojet bomber.
NORTHROP GAM-67 CROSSBOW:
_____________________ _________________ _______________________
spec metric english
_____________________ _________________ _______________________
wingspan 3.81 meters 12 feet 6 inches
length 5.82 meters 19 feet 1 inch
height 1.37 meters 4 feet 6 inches
loaded weight 1,270 kilograms 2,800 pounds
maximum speed 1,090 KPH 675 MPH / 587 KT
service ceiling 12,200 meters 40,000 feet
range 480 kilometers 300 MI / 260 NMI
launch scheme RATO booster or air launch.
recovery scheme Parachute.
guidance system Autopilot with radio control backup.
_____________________ _________________ _______________________
Only 14 Crossbows were built before the program was cancelled in 1957, in favor of more sophisticated technology that ended up being cancelled in turn. However, it did point the way to the range of missions that would be performed by UAVs in later decades. * The Northrop Ventura "AQM-38" was a rocket-propelled target that was used for training Army Nike anti-aircraft missile crews and Navy fighter pilots. It started life in 1957 under a US Navy contract as the "RP-70 / XKD4R-1", with initial flight in January 1958. After a bit of redesign that changed its lines somewhat, it went into service with the Army and the Navy from 1959.
The Army version was originally designated the "RP-76", with this designation changed in 1963 to "AQM-38A"; while the Navy version was originally designated the "RP-78", with this later changed to the "AQM-38B". The Army AQM-38A had slightly subsonic performance, while the Navy AQM-38B had a more powerful engine, giving it a top speed of Mach 1.25.
Like the Crossbow, the AQM-38 had a cigar-shaped fuselage and guidance provided by an autopilot with RC backup, but it was much smaller and was powered by a solid rocket engine, with an exhaust nozzle just behind each wing. It had shoulder mounted delta wings, three fins around the nose, and a peculiar downward-mounted "tee" tail along with a smaller dorsal fin. It was air-launched and recovered by parachute.
NORTHROP AQM-38B:
_____________________ _________________ _______________________
spec metric english
_____________________ _________________ _______________________
wingspan 1.52 meters 5 feet
length 2.95 meters 9 feet 8 inches
height 0.46 meters 1 foot 6 inch
empty weight 90 kilograms 200 pounds
launch weight 135 kilograms 300 pounds
maximum speed 1,530 KPH 950 MPH / 826 KT
service ceiling 22,000 meters 72,000 feet
endurance 23 minutes
launch scheme Air launch.
recovery scheme Parachute.
guidance system Autopilot with radio control.
_____________________ _________________ _______________________
The AQM-38 appears to have been largely made of plastics, and carried radar enhancement devices to simulate larger aircraft. It went into service in 1959 and over 2,000 were built. It appears to have been replaced by the Beech
AQM-37, discussed later, and was phased out in the early 1970s.
* By the late 1950s combat aircraft were capable of Mach 2, and so faster targets had to be developed to keep pace. Northrop designed a turbojet-powered Mach 2 target in the late 1950s, originally designated the "Q-4" but later given the designation of "
AQM-35". In production form, it was a slender dart with wedge-shaped stubby wings, swept conventional tail assembly, and a GE J85 turbojet engine, like that used on the
Northrop F-5 fighter, with 17.1 kN (1,745 kg / 3,850 lb) thrust mounted under the tail. It was 10.7 meters (35 feet) long and weighed 1,500 kilograms (3,300 pounds).
The
AQM-35 was air-launched by a
Lockheed DC-130 Hercules drone controller aircraft, or other carrier aircraft. The AQM-35 was only built in limited quantities and never reached full operational service.
* In the late 1940s, Lockheed developed an air-launched high-speed
ramjet research vehicle designated the "X-7" for the USAF. It was a long dart with trapezoidal wings, and used two solid-fuel booster rockets to get it up to ramjet speeds. The X-7 was used for engine and flight research through the 1950s. The Air Force ordered a minimally-modified target variant of the X-7 in the late 1950s as the "XQ-5 Kingfisher", later redesignated "AQM-60". The program was transferred to the US Army and then killed in the mid-1960s after the construction of about 61 vehicles. Some sources claim that it was cancelled simply because it was too fast to be caught by existing surface to air missiles (SAMs), but that sounds a bit glib.
It was more likely that it redundant. During the same timeframe, North American also built a Mach 2 target drone for the US Army, designated the "MQM-42A Redhead / Roadrunner". It was another sleek dart, with mid-mounted small delta wings, an inverted vee tail, and a Marquardt
ramjet engine on the back. It was launched by RATO booster, derived from the solid fuel motor for the Honest John battlefield rocket, and was recovered by parachute. The MQM-42A had a length of 7.57 meters (24 feet 10 inches), a weight of 400 kilograms (900 pounds), speed of up to Mach 2, and ceiling of up to 18,000 meters (60,000 feet). First flight was in 1961. The MQM-42A was apparently built in modest numbers, and used for training
Hawk SAM crews. It remained in service into the 1970s.
* While the
Radioplane BTT was a popular piston-powered target, such a simple target was relatively easy to build and it had competition, particularly in the form of the Beech "Cardinal" target.
In 1955 Beechcraft, now part of Raytheon, designed the "Model 1001", as the initial version of this target drone was designated, in response to a US Navy requirement for gunnery and air-to-air combat training. Production of the type began in 1959, with the drone being given the Navy designation of "KDB-1", later "MQM-39A". The Model 1001 led to the similar "Model 1025" for the US Army, which gave it the MQM-61A designation. Beech also designed a variant powered by a turbojet engine and designated "Model 1025-TJ", but nobody bought it.
The MQM-61A was a simple monoplane with a vee tail. It was substantially larger than the Shelduck, and powered by a 94 kW (125 HP) McCulloch TC6150-J-2
flat-six, air-cooled, two-stroke piston engine driving a two-blade propeller. It could tow banners or targets of its own, with two targets under each wing, and also carried scoring devices.
BEECHCRAFT MQM-61A CARDINAL:
_____________________ _________________ _______________________
spec metric english
_____________________ _________________ _______________________
wingspan 3.95 meters 13 feet
length 4.60 meters 15 feet 1 inches
height 1.02 meters 3 foot 4 inches
launch weight 301 kilograms 664 pounds
maximum speed 560 KPH 350 MPH
service ceiling 13,100 meters 43,000 feet
endurance > 1 hour
launch scheme RATO booster.
recovery scheme Parachute.
guidance system Autopilot with radio control.
_____________________ _________________ _______________________
A total of 2,200 Cardinals of all variants was built, the majority for the US Army, with the rest operated by the US Navy, the US Marine Corps, and by Spain. Some may have also been operated by Germany and Switzerland. It is now out of production, though a few may linger in service.
LEMUR Rovers: LEMUR IIa
