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Post World War One Development of Balloon Barrages

                After the Great War, air defence became an increasingly important item on the military agenda. The concept of using balloons to form an apron or screen across vital parts of London was tried and tested by the military throughout World War One. There have been many points put forward by historians to support or decry the use of such a defensive screen.

Following the air raids on Britain 3rd to 4th September and 4th to 5th September 1917 it was realized that in good weather, with a good moon, night attacks on the South-East of England and London were quite easy to carry out. There was no regulated blackout and landmarks such as the Thames river were well defined and easy to find and follow. 

Major-General Ashmore, Commanding Air Defences, London Area, somewhat radically, proposed to borrow one of the spare Caquot Observation balloons, used as a spare by the various Corps in France, to be brought over with winch and personnel.

The idea was to be able to surround London with a floating screen of vertical thin wires, the wires being held aloft by a series of Caquot Balloons joined together by horizontal wires.

                It worked after a fashion but had flaws in that the weight of the wires was quite considerable and this meant that the lifting power, and thus altitude, of the balloons was limited. In addition the balloons were designed to be placed in units of three. If any one of the three balloons lost hydrogen gas then the other two could not support the entire aerial screen and collapse was likely. It had been worked out that, in theory at least, it would have been possible to completely encircle London with a ring of balloons and a vertical screen to deter raiders from attacking the city.

                The result was a screen that never amounted to more than 30 balloons in total, placed to the east of the city, leaving much of the city vulnerable. Below is an artist’s impression of how the final defence was likely to have looked, with hundreds of balloons surrounding London . Such an arrangement would have meant that the enemy would have had to find a way to fly at higher altitudes and fly over the barrier. The return journey would have been easier as the plane would have been lighter after dropping any bombs and thus much more likely to get over the apron to fly home.

The balloons were of the Caquot design and were placed 500 yards apart. Initially five balloons were tried by General Ashmore but later reduced to three as it was too complex flying five. Each balloon had a winch and crew of some 30 men. One problem with three was that the central balloon always flew lower and meant the apron was not so high in the middle. If any one of the three balloons lost lift then the entire structure was endangered as the remaining two balloons were unable to keep the structure flying.

      The original horizontal wires connecting the balloons were only 3.5 mm thick and the vertical ones designed to trap aircraft were 1.7 mm thick, placed 25 yards apart and hung down for 1000 feet only, such thicknesses would not be visible easily to the naked eye. The maximum flying height was from 4,000 to 8,000 feet and was designed to be used only at night. No more than ten balloon aprons of three balloons each were ever flown.                These were placed East and South-East of London and eight extending from the Thames to Edmonton and two from the Thames to East Wickham . Three different types of balloons were used:

 1. 33,000 Cubic feet Caquot, altitude 8,500 feet.

2. 40,000 cubic feet Caquot, altitude 9,600 feet.

3. 37,000 cubic feet, Italian, altitude 11,000 feet.

                On nights when a raid was possible the balloon were let up to about 2,000 feet in readiness and when an air raid was taking place they were flown at maximum height.

In 1919 more proposals were made by General Headquarters at Horse Guards in London .

                In 1924 discussion was raised over the use of multiple or single balloon systems. Multiple balloons gave multiple problems. It was thought that to have a 10% chance of downing bombers then one would need to have at least seven balloons to every mile, (assuming the bomber had an eighty foot wingspan). Ten balloons per mile gave a chance of one aircraft in seven being brought down. The winches used to fly balloons in the Great War were known as the “Sandycroft” type. These utilized a 40 H.P. engine and a winding unit governed by a crude system of gearing. At the end of the war these were all written off so a brand new winch design was needed. It was suggested that Scammell and Nephew, who were the principal Kite Balloon winch designers and manufacturers of winches in the Great War,  had put forward a design of a self-contained winch on a caterpillar tractor unit, making it mobile and able to go almost anywhere. It was this concept that gave birth to the winch lorry used in WWII. By having a mobile balloon the enemy pilots could never be sure where it might be at any one time and specific targets could be much more easily defended.

                It is interesting to note that while many plans and discussions centered around the use of a balloon as an offensive device, the British had not been slow to realize that what one man invents another man can discover and any potential enemy was likely to be considering a balloon screen of a similar design. So in 1924, it was decided to investigate how we might counter the cables attached to balloons and designs were put together to use fenders to push any cable away from the wings and propeller while in flight.

In 1925 much research was taking place into the use of balloons, the Royal Airship Works at Cardington, Bedfordshire, had tried manufacturing a balloon for air defence. In trials it behaved badly, on filing with hydrogen, the gas filled the forward 1/3 of the balloon and the remaining 2/3 failed to inflate and hung vertically down in a sheet of rubberizes fabric. Consequently it became unstable.

                Later, C.G. Spencer & Sons Ltd, of Highbury Grove, London who were well known makers, (from 1835), of Balloons, Airships, & Gas Containers were contracted to manufacture a modern design balloon. In August 1925 a trial of the new balloon was held at Pulham. At ground level it took 119,000 cubic feet of gas and was designed to go to 30,000 feet altitude. The balloon was some 200 foot long, weighed 2 tons and 8 cwt, with a cable of 1 ton. The calculated lift was such that it should be able to reach 30,000 feet and raise all the cable as well as 750 lbs in weight. Its shape meant it could stand a 20 knot wind; it should be able to fly at 30,000 to 20,000 feet for at least a week. 50 personnel were needed to inflate the balloon in a shed    and up to 100 would be needed to walk from the shed to the winch in a 15 mile-an-hour-wind.

                The trials were carried out on the 9th September 1925 and the balloon when let up got to about a 1000 feet and then began to behave strangely. It ended up with a bend to starboard and went into a dive. The gas surged up to the stern area causing the balloon to face nose down and the bows hung down empty. Attempts to winch it in failed as the massive lift exceeded the pulling power of the winch. It was eventually brought down with a Clayton tractor and a snatch block.

                Analysis indicated that between 4 or 5 curtains should be fitted in the balloon to reduce gas surging, with consideration being given to a ballonet system, and the air scoops be modified in terms of position, number and to have non-return valves fitted.

A second trial the following day was equally unstable and the balloon was winched in deflated and Spencer’s began the fitting of curtains to prevent gas surging, although one of the RAF Flying Officers still thought a ballonet was the answer. A trial took place on the 7th October 1925 . This was a rerun of the previous except that it all went wrong at around 50 feet, with suspension cables from the final lead off breaking and the parabola on both port and starboard sides was torn away starting from the aft area. The final hole was about three panels in width. This meant that most of the gas escaped. The balloon was taken back into the shed for drying.

                In February 1925 it appears that the Royal Airship Works at Cardington were making a balloon due to be finished in March and Spencer’s were making or modifying their design due to be finished in April. Delays with a new type of cable and upgraded winches delayed the whole thing well into May 1925. By June 1925 there was an experimental balloon in existence at Pulham. It was of a 4 lobe design by the Royal Airship Works taken from a design at the Royal Aircraft Establishment. In addition Spencer’s now had a balloon almost finished that was fundamentally different from the Royal Airship Works design. At a final trial, Spencer’s balloon

failed and the Air Ministry was of the opinion that Spencer’s did not have the technical ability and qualifications to produce a working High Altitude Kite Balloon.

It was decided to find a suitably qualified Kite Balloon designer and the director of the National Physical laboratory provided a Mr Bateman on loan from February 1926. In addition a former Great War Kite Balloon officer (Flying Officer Steff) was posted to Cardington. In August 1926 it was revealed that work was proceeding urgently to design a balloon and a mobile winch at Cardington, Pulham, Farnborough and the National Physical Laboratory. The winch was being constructed at Farnborough.  Full scale experiments with the “R” type balloon at Pulham to help design the “Z” type balloon were expected to be completed shortly.

                In November 1927, it appears that there were two “Z” balloons in existence, one at Cardington and one at Spencer’s, although the latter company were noted to be making slow progress with the project.

Some costings surfaced, showing that to have a 70 mile stretch of land protected by single cable aircraft barrage at 10,000 feet, with 500 yard spacings, was likely to cost around £1.3 million pounds, a not inconsiderable sum. It was not until April 1928 that Spencer’s balloon was back at Pulham or an air inflation test. It failed due to an inspector from the Royal Airship Works had found that some 520 internal rubbers. In addition the fabric had lost 10% of its original strength. One must remember it was now some several years old and had been kept in a shed inflated with low pressure air. These perished areas needed attention and no suitable winch was available to fly the balloon. It was also stated that much of the original fabric had deteriorated in terms of gas permeability and the use of the existing fabric was not to be continued.

                Much more research and experimentation took place but it seems that Spencer’s gave up and Cardington became the center of excellence for balloon design and experimentation.

Right through the 1930’s much experimentation and design took place in Britain with most centered at Cardington.

By 1930 the Barrage Balloon as it was to appear had now arrived. Auxiliary Squadrons were formed to operate the balloons and when a balloon was flown as an exercise in pre-war days vast crowds would attend the scene.

                On the outbreak of war they were numerous enough and widely distributed to put up a credible, reassuring presence to both the public at home and the Luftwaffe.

A number of individuals tried Post-War to lay a claim for the invention of the Balloon Aprons and tried to obtain payment for their idea. As one reads through the various inventors ideas in the patent documents it is clear that some of them were well thought out, particularly those from a defence background, but many of the ideas were rather impractical to say the least. Others were patents for balloon related defences that had already been tried out in secret and abandoned. Many of the patents that were put forward during WWII were considered to be of possible use to an enemy and were not publicly attributed until after the war.

                It was very obvious to many military minds that the use of aircraft was a major asset in any future conflict. Today it is a well accepted fact that in any conflict air superiority is the one thing that can make a victory more likely.

The possibility of inventing a better aerial defence clearly stimulated a number of inventors who looked at the problem and designed ingenious ways to defend the skies. In World War One a Balloon Observer unit had put up an old worn out balloon with a straw dummy pilot and loaded the observer basket with explosives. This was because they had been attacked repeatedly by Rudolph von Eschwege, a German Air Ace who was on a Balloon busting mission. He attacked the lethal balloon and was blown up when the charge detonated. This was the first time that a balloon had been used to hoist explosives aloft to bring down an enemy plane.

                In December 1936, Phillip Gorst and Geofrey Clapham submitted a Patent application to the British Patent Office: “Improvements in or relating to Air Defence Aprons.” They proposed that an air defence could be made by using “parachute units”, to trap aircraft at altitude. They suggested that there could be two variations. The first could be a parachute attached to a cable of two to three thousand feet in length. The second was a similar unit but with a cable of some 300 feet. The general concept was that the units could be deployed at various altitudes in varying numbers. They would be designed to descend at around five to six feet per second. At the lower end was attached a weight made up of a small bomblet and a parachute at the upper end. As the device unfurled the bomblet would straighten out the wire and begin to descend. It was envisaged that the bomblet would be fired by percussion or by use of a timer. The timer system was designed to destroy any bomblet that had not been involved in the damage to an aircraft before it reached the ground.

                The units were to be capable of launching from aircraft, or maroons, and to be encapsulated in artillery shells to reach varying altitudes. They proposed that if released by aircraft they would be released every 180 feet at several differing altitudes. The units would be sent up to altitudes of say 16,000 to 19,000 feet once alerted by ground stations of the approach of enemy aircraft.

                They would be sent in a line at right angles to the course of the aircraft with a second line of launching devices some miles behind the first. The concept was problematic in that the method of crating these aerial bombs to the right density at the right time was never going to be easy. What was well thought out was the concept of the aircraft striking a balloon cable and as it moved forward the cable would form a “v” shape over the leading edge of the wing. The parachute would be dragged behind the plane and this would cause the bomblet to rise until it struck the aircraft, thus destroying it. Other versions used a parachute and bomblet at the upper end of the cable and a retarding device on the lower end of the cable. Either way the concept of the cable being drawn across the wing and dragging a bomb into contact with it was sound. As far as is known the concept of scattering parachute units to the sky to form a defence was never utilized, although operation Albino was carried out and consisted of ground releases of large spherical balloons with a bomb attached.

                The final specification for the patent was modified several times and finally accepted in June 1938.

                In February 1937 Gianni Caproni, an Italian patented an Aerial Barrage idea. He had taken the idea of Gorst and Clapham and added a balloon to it. This meant that on releasing the balloon it would float up and on reaching a certain pre-determined height it would burst or use a pre-set deflation valve. On deflation the parachute would open and the bomblet would now float down attached to the cable and the parachute. He proposed variation in terms of single balloon, a vertical chain of balloons or a large bunch of balloons. The final patent was accepted January 3rd 1939 .

                In March 1937 Alfred Graham of there Royal Aircraft Establishment submitted a patent for Improvements in Aerial barrages. His idea was that in order to get maximum affect on an aircraft wing it was important to ensure that however the cable broke, the lower and upper portions of the cable had attached to them parachutes that caused the cable to drag over the wing and stall the aircraft if not cut off the wing. The parachutes were made of adjustable areas to get maximum drag. One other variation was to have just one parachute and a free cable at the other end. This simple design was used very successfully with the unarmed cable designs throughout WWII.

It was published in May 1946.

                In March 1937, Alfred Graham of the Royal Aircraft Establishment submitted two patents of a rather elegant idea. This was to improve on previous patents for an Aerial barrage. He proposed that a device using long cables that was suspended from a fixed structure (e.g. balloon) moored to the ground or even a moving aircraft should have incorporated in it at intervals along its length bomblets, each bomblet being associated with a  one-way inertia link along the length of the cable. When a hostile aircraft struck the cable the resulting tension wave in the cable caused the link to cut the cable. This released a length of cable and a bomblet to swing around the wing of the aircraft and destroy it. The final patent was accepted May 1946. Little did he know what would become of his idea for the inertia link.

                In June 1937, Herbert Robins, of Royal Engineers Mess at Brompton Barracks submitted a further patient to improve aerial barrages for use against aircraft. This was specific to the bomblet and it’s mounting to the lower part of a cable.

It was a spring loaded percussion fuze bomb that slid on the cable and on impacting the cable two things took place: An electrical  detonator cut the cable below the bomb and the cable and bomb were drawn up to strike the wing, this caused the fuze and striker to be hit together causing an explosion and destroying the aircraft.

                While much thought had gone into Aerial barrages, other people grappled with the problem of combating an Aerial Barrage. In 1937 James Martin of Uxbridge submitted a patent for protecting an aircraft by having a device fitted to an aircraft that would cut a cable that might be attached to an Aerial barrage. His device was used on many aircraft throughout WWII. It was finally published in November 1945.

                In May 1938, George Whitehead of Cardiff submitted a patent for wind operated devices in elevated positions to obstruct or destroy hostile aircraft. These devices were an improvement on the existing barrage balloon system. They were to be deployed into the path of enemy aircraft by using rockets or a large catapult or by towing with other aircraft and were designed to foul the propellers. It had a helicopter type propeller device that was rotated by an air turbine that was operated by the prevailing air current found at altitude. The design was lighter than air as it had gasbags fitted to give it lift, it would be floated to position and then the propeller device would begin to rotate and stabilize the device. It was intimated that it could be made from celluloid for lightness. It was unarmed and relied on the cable being wound around the hostile aircraft propeller. As far as is known it was never tried out. It was published in February 1940.

                In July 1931 Alfred Bawtree of Sutton, Surrey , submitted a patent for improvements in bombs for use in Aerial Entanglements. He claimed that his bombs were designed to be attached to threads on parachutes. He envisaged a screen of 500 lines, twenty feet apart and each 2000 feet long would give a bomb density to cover two miles long and two thousand feet high. He realized that most of the bombs would not have any contact with the enemy and proposed a system to render them harmless as soon as they hit the ground. This system would separate the charge and the detonator. As far as is known it was never used and was published February 1941.

                In August 1939, James Martin submitted yet another patent designed to improve the means for use on aircraft for severing cables. It was specific for aircraft wings that had been fitted with de-icing bags which may have got in the way of a cable that needed to be cut. It was published in August 1946.

In August 1939 Arthur Ryner of London submitted a patent for “Improvement in Kites”.

These were described as dirigible weather resisting kites made of various light materials that could be flown say from the stern of a ship and like modern stunt kites be made to move in various directions and thus be placed into the path of a hostile aircraft. He shows a design in which a ship has two sets of fourteen kites aloft at the stern. It was published in January 1941.

                In October 1939 Joseph McCann of Liverpool , submitted a patent for countering raiding aircraft. He envisaged a device called a trap that would become attached to a enemy aircraft and then deploy as a result of wind resistance. On deploying a parachute would open and cause considerable drag on a aircraft and possibly cause it to stall. The traps were held aloft by use of balloons in a similar manner to the original balloon apron of London used in the First World War, a collection of traps forming a “mat” in the sky. They could be flown from kites from the stern of ships and even dangled from suitable aircraft. He shows several diagrams of a trap made up of four parachutes on one cable wrapping around an aircraft and disabling it. It was published in 1941. As far as is known it was never used.

                In November 1939 Josef Dorremysl, from Czecho-slovakia, living in Redditch submitted a patent for Aerial Bombs. He stated that this was designed to be used on bombs that were to be suspended from cables and parachutes to destroy enemy aircraft. The crux of his design was to have a bomb that was harmless at all time except when in suspension. He used a percussion fuze that responded to tension in the cord or cable so that the percussion mechanism was controlled. The fuze only became into use when the bomb or the cable had been impacted. Once the tension in the cable ceased the bomb was automatically made safe, and even if circumstances restored the tension the bomb was still rendered inactive. It was published in May 1946. As far as is known the idea was not experimented with as once a balloon cable bearing a bomb had been recovered and hauled in it was the responsibility of someone to make safe and remove the bomb.

                In April 1940 The Standard Telephone and Cables Company along with Leonard Powell submitted a patent for determining the tension in a barrage Balloon wire. The novel idea was to use a telephone system to provide an alarm if the tension in the cable went above or below pre-set limits. The idea was to combine a telephone subscribers line with the barrage balloon cable, and using a magneto system, cause a normal telephone calling signal to occur when the tension was outside of the limits expected. This gave remote supervision of the balloon cable.

It was published in October 1941.

                 In October 1940 Serge Viazemsky, a Russian living in London , submitted a patent for improvements in or relating to the manufacture of Balloon Barrage apparatus. One idea he claimed was to find a way to extend the height at which they flew. The other ideas were to make the balloons behave more naturally when raising or lowering them. This was a design that created a tandem design system so that one balloon flew above the other. To facilitate this, the lower balloon had a tubular channel made through it to allow the cable for the upper balloon to pass through unhindered. As far as is known it was never used in wartime. It was published in July 1942. However tandem balloons were used in the atomic tests of the 1950’s.

                In October 1940 Bertrand Martin of London submitted a patent for “Improvements in and relating to Kite balloons and the like”.

He had the idea of flying several balloons at the same time in a vertical or substantially vertical series. His idea required each balloon to be attached to the one below it. It was published in April 1942. Again this system was used experimentally only but was used in the atomic tests of the 1950’s.

                In December 1940 Edwin Meeson of Coventry submitted a patent for Improvements in Devices for Intercepting Aircraft”. His idea was that barrage balloons could only fly at a limited height and their effective range could be enhanced by adding a system to fly streamers out above the balloons. He felt that streamers could be flown at heights of up to 30,000 feet. The streamers were novel in that they were composed of two sheets of cellulose that were formed together to from a series of pockets, not unlike the bubble wrap so often seen today. He suggested that these could be filled with hydrogen and even have a thin wire embedded in them. The concept was that the streamers were lighter than air and would float above the balloon and when an enemy aircraft came along it might wrap the streamer around the propeller and be destroyed. As far as is known the idea was never experimented with. It was published in August 1942.

                In December 1940 John Pinder from Enfield submitted a patent for Improvement in and relating to Balloon-supported Net and like obstructions against hostile aircraft. His idea was to have a rapid and simple method of releasing in conjunction with existing barrage balloons a series of couple balloons at an altitude of several thousand feet that would form a net. These would be a pilot balloon and two auxiliary balloons. Once the barrage balloon was aloft the net balloon structure was slipped onto the cable and rose up until it hit an inverted cone on the balloon cable on hitting the cone it was released from the cable and allowed to drift around in the sky. As far as is known this was never experimented with but Operation Albino did use free floating balloons with explosive charges.

                In January 1941 Alfred Watson of Beccles submitted a patent for Improvements in or relating to Aerial explosive Mines”. His idea was that a single large balloon could be sent aloft into areas of the sky where raiders might be flying and by seeding the sky with lots of these devices an enemy aircraft might be destroyed. Each device was a magnetically detonated by an aircraft approaching it. Each mine was fitted with devices that would ensure it was destroyed after a certain time preventing them returning to earth and becoming a danger to the public. The patent was published in July 1942. Operation Albino used this idea but it was suspended after it was realized that many of the balloons drifted to other countries and exploded there while many descended back to earth in a dangerous and live condition

                In March 1941 Arthur Fermor of Surbiton submitted a patent for an Air Mine. This was designed for use on night raids by enemy aircraft. The idea was to use a single balloon black or light yellow in colour with sufficient lift to take an air mine to an altitude where it may drift around and collide with enemy aircraft. The mine will have a system that will prevent from falling to earth as a live charge and will be detonated after a certain time period has passed. It will also have a system that if the balloon bursts the bomb will detonate on an increase in air pressure as it descends or by a small propeller spinning as the bomb falls. Each balloon will have a adjustable pressure operated valve to ensure that it floats at a steady altitude with a variation on each batch so that at a curtain of mines is to be seen floating at several altitudes over an area where night flying by the enemy takes place. As the enemy approaches the balloon and bomb combination could be detonated on contact or by electrical, mechanical or magnetic devices if only the cable were struck. The devices could be released in pre-prepared batches. The patent was published in October 1942.