Category Archives: World War II

Operation Outward: Military Success For Very Little Outlay

In the dark days of September 1940, Britain and the Commonwealth stood alone. The Nazis occupied most of Europe, the Japanese were on the offensive and had the upper hand in the Far East and even Egypt and the Middle East weren’t safe. Fear of invasion from Italian forces in North Africa had stretched the British Army to breaking point. The fiasco that was the rout at Dunkirk had had a positive spin put on it by politicians and was made to be seen as a victory. In reality, it was a defeat — most of the modern tanks, vehicles and heavy weapons that had gone to France with the BEF had been left behind. Prime Minister Winston Churchill called for action but what action could the country take when so thoroughly on the back foot? Then on the night 17/18 September 1940, Britain conducted a stealth raid into occupied Europe. A raid so stealthy, they didn’t know they had done it!

Strong winds had broken loose a number of barrage balloons from their moorings. These balloons drifted across the North Sea and (crash) landed in Denmark and Sweden. The sturdy steel cables trailing from the balloons caused damage to power lines, careered into railway traffic and collided with the antenna of the Swedish International radio station, causing it to go offline for a while. Five balloons (but maybe more) were reported to have drifted as far as Finland.

How many balloons had ‘escaped’ was never reported but upon hearing the news of the damage and confusion they caused, Churchill was jubilant. He reasoned that if such a low cost ‘weapon’ could do this, then a further, more detailed study should be taken with a view to doing something along the same lines…but deliberately.

In fact the matter had already been investigated a few years earlier. The British Air Ministry had begun producing barrage balloons as far back as 1936. Forward thinkers had seen the war clouds gathering so in 1937 the Air Ministry conducted a study to determine how much damage a balloon could cause if it broke free from its mooring and its steel cable was dragged across the countryside. The study showed that, if the steel cable were to short out power lines, electricity supplies would be out for at least six hours. This study had been undertaken as a Civil Defence measure — to determine how long people and industry would be without power in the event of an accidental balloon drift over Britain. The use of barrage balloons as an offensive weapon had not been considered — until Churchill became involved.

Initially the Air Ministry opposed it on the grounds that the balloons would interfere with flight operations. Friendly balloons floating about in the darkened skies might become entangled with RAF aircraft. It also argued the point that these balloons were unguided and uncontrollable and any success would be more by chance than design. Retaliation in kind by the Germans from the occupied coasts of Europe could not be ruled out either.

In contrast, the Admiralty Board was more open to the idea, arguing that it was a ‘cheap and cheerful’ way to strike back at the enemy. Comparing the cost of a balloon to a front line bomber was persuasive and, as there was also an ample supply of hydrogen gas for the balloons, the program started in earnest. Meteorological studies had shown that more winds blew from Britain towards the continent than blew from the continent towards Britain. In an average year the prevailing wind was west to east 55% of the time and only east to west 38% of the time. This made the idea of German retaliation highly improbable and probably less effective if implemented. More importantly an engineering study had shown Germany’s power grid was considerably more vulnerable to damage by short-circuit than the British system. Coupling this with the fact that large pine forests (which were considered more vulnerable to incendiary attacks than British hard wood forests) covered many parts of the German heartland and continental Europe, the program was begun. However, as with all things involving two branches of the British military a long, bureaucratic struggle between the Air Ministry and the Admiralty began. The programme was held up until September 1941 when the go-ahead was finally given: Operation Outward would commence.

Standard British barrage balloon. This is the type employed to use the trailing cable in offensive operations.

The Balloon Goes Up

The first launch site was Landguard Fort south of Felixstowe situated in a remote southern part of Suffolk. Originally built as one of a string of Napoleonic Forts for home defence, it was situated at the mouth of the River Orwell. Designed and built over a century earlier, its purpose was to guard the entrance to the port of Harwich (and the surrounding area) from the perceived Napoleonic invasion threat. An old imposing structure with high, thick walls, it would be able to store the balloons and their associated equipment, whilst keeping prying eyes at bay.

Following detailed studies and tests of balloon designs, two types of balloon were to be used. The first type was a typical eight feet round weather balloon modified to carry three six pound incendiary ‘socks’. These socks were designed to set fire to pine forests and heathland. A second balloon tested was similar to, but not as large as, a standard barrage balloon. This smaller barrage balloon would trail a long steel cable which, it was hoped, would hit power lines and create a short circuit. Tests were conducted on the balloons regarding duration of flight and with a timed ‘burn fuse’ attached. This saw their ceiling height set at about 16,000 feet, give or take a few hundred feet for wind and other atmospheric conditions. Natural leakage of the hydrogen gas from the balloons, along with a timed deflation valve obviated the need for any ballast or pressure-control systems to control and maintain altitude. As the Spitfire fighter and Lancaster bomber could fly in excess of 20,000 feet, the balloons should not interfere with any normal RAF flight operations.

With the balloons simple and easy to operate, no expert crew had to be employed in their usage. Fighting men could be freed up and used elsewhere so the role of balloon handlers fell mainly onto the shoulders of the WRNS (Women’s Royal Navy Service) or WRENS (as they were commonly called). These personnel were supervised by a few (male) NCOs and technicians! A detailed plan for launching the balloons was introduced so as not to conflict with either incoming or outgoing RAF flight operations. Times were set for balloon launch operations but these could be changed if RAF aircraft were grounded due to bad weather. The balloons could fly even if the aircraft could not.

The first launches took place on 20 March 1942 and, within a few days, encouraging reports of forest fires near Berlin and in East Prussia were received. Radio intercepts showed that the Luftwaffe was sending up fighters to try to destroy the balloons. This was very encouraging news to both Churchill and the combined RAF and Admiralty operation. It would appear that the Germans were spending far more resources trying to destroy the balloons than the British were by launching them. Sending up fighters to try to destroy the balloons meant they were using extra fuel, putting more strain onto airframes, increasing aircrew fatigue etc. Whilst the Germans did their best to intercept as many balloons a possible, they soon realised they were fighting a losing battle.

Reports from French Resistance cells and other, neutral sources claimed that the balloons were causing a lot of disruption to rail, road and agriculture operations and services. These encouraging reports reached the ears of the French Government in exile in London, and they wanted more released to help tie down enemy forces.

The balloon operation had proven successful — for very little outlay a lot of disruption had been caused. These initial successes led to two other launch sites being set up in April and May 1942. One site chosen was on the coast at Oldstairs Bay between Dover and Deal in Kent, the other being Waxham in Norfolk. The latter site was an isolated coastal village north of Great Yarmouth. These sites brought anywhere from Northern France to Scandinavia within a balloon’s sphere of operation with a good wind blowing to the continent.

Success for the Balloons

Whilst the balloons proved to be an economical way to strike back at the enemy in the short term, they were never intended to be a realistic military weapon to cause mass damage or destruction. Their launch was seen as being of a nuisance value. Although they did tie up a lot of enemy manpower resources, in reality they caused very little military damage. People in the higher chain of command began to doubt that the effort put into this operation was worth it. However, the night 12 July 1942 began to change a some minds. A cable-trailing balloon struck a 110,000 volt power line near Leipzig. The overload switch in the nearby Bohlen power station did not trip quickly enough and this resulted in a fire which spread and destroyed the entire complex. The damage was estimated at £1,000,000 compared to the £220,000 spent on Operation Outward.

By August 1942 up to a thousand balloons per day were being released, weather permitting. The Germans were now tied up fighting in the east and the balloons seemed to have free rein over the skies of occupied Europe. Some reports even state they reached as far as Hungary. The German military were engaged in fighting in the Soviet Union leaving it to the German civilian services to try to fight the ‘balloon war’ on their own.

Own Goals

The balloon offensive had proven a success but this success did come at a price. On the night of 19/20 February 1944 a cable-trailing balloon shorted out a Swedish overhead rail lighting system. This short circuit of the system resulted in a collision between two trains. The number of people injured or fatally wounded was never revealed but a diplomatic protest was issued by the Swedish government. Other than to say sorry and perhaps compensate a neutral country for any material loss, there was little the British government could do. This unfortunate incident did prove without doubt the potential of the balloon campaign, raising the question of how much damage wasn’t being reported by the German authorities.

End of Operations

With the tide of the war turning in the Allies’ favour and having achieved virtual air superiority over occupied Europe, it was decided that the number of balloons being released should be cut back. From May 1944 a change of tactics was also implemented. Mass balloon launches were stopped and replaced with a trickle of balloons launched from the three sites at ten-minute intervals throughout daylight hours. Only 2% of these balloons were to be of the trailing wire type — a type which could have caused major damage to allied aircraft. The remaining 98% carried of incendiary bombs. Cutting back on balloon launches increased the availability of hydrogen gas for use elsewhere and freed up much-needed transport vehicles and compressed gas cylinders ready for the planned Normandy landings. With the success of the D-Day landings on 6 June 1944 and with the Allies making gains into Occupied Europe the last offensive balloons were launched on 4 September 1944.

Further Research and Reading

Thanks to something Alan Hamilton said on the SOTCW Forum I set off to research this unusual operation. Using Google as my first port of call most of what I have written here is gleaned from various sources online. There is still a lot of technical, detailed information about Operation Outward that I haven’t included. I haven’t set out to write a complete history of the Operation but just to give the reader a taste of something unusual that happened in the darkest days of WWII. It would be advisable to read this article in conjunction with online maps and images of the locations mentioned. That way (hopefully) you’ll be able to see how remote and secretive the chosen balloon release sites were. I hope you enjoy it.

Featured image: The National Archives UK [OGL v1.0]

Article by Grant Parkin.

War flag of the Imperial Japanese Army

An unusual Japanese AA Weapon

The Quarterly Newsletter of ‘The Ordnance Society‘ has been carrying a series of short four or five page illustrated articles on Imperial Japanese weapons of WWII, at least the more unusual ones. In Numbers 116 and 117 the suicide ‘lunge-mine’ and the incredible 70mm anti-aircraft barrage mortar are featured (I made one of the latter following C.O. Ellis’ brilliant, instructive articles in Airfix Magazine over fifty years ago). The most recent issue deals with a weapon I had never heard of — Japanese cyanide grenades. The series, written by Peter McAllister, is excellent and is set to continue in future issues. As a wargamer I find the content intriguing and valuable – something to be aware of if you field an Imperial army of the period.

The 70mm Anti-Aircraft Barrage Mortar (7cm Uchlaqe Sosoku-Dan)

During the history of warfare many combatants, from all periods, came up with ideas that worked far better in theory than they did in actual reality. The Imperial Japanese Army (IJA) during WWII was no exception. One of the many ideas the weapon designers of Japan came up with was a rather clever type of anti-aircraft mortar. A surprising amount of thought went into this weapon, available in two calibres, 70mm and 8lmm. I will take a look at the far more common example, the 70mm design.

Drawing of the 70mm Anti-Aircraft Barrage Mortar
70mm Anti-Aircraft Barrage Mortar

The IJA had a fairly sophisticated array of anti-aircraft weapons, aiming systems and detection devices. Why they thought, then, that they needed something as strange as an anti-aircraft mortar is, at first glance, a bit of a mystery. However, at closer inspection it can be seen that there was a strange current running through at least some of the IJA’s weapon design process. One only has to look at the hopper fed Type 11 light machine gun or the mass of (mostly unused) accessories that came along with some manufacturing runs of the Type 99 rifle. And let’s not even discuss the unneeded design of the Type 2 paratrooper rifle. Each of the above examples has something in common with the 70mm anti-aircraft mortar. In theory, they were good ideas but in practice were at least an irritant to the user – if not worse. In short, the IJA infantry’s having a light anti-aircraft weapon on hand in all terrain was a good idea but making that weapon a mortar? Not so much.

The 70mm version of the anti-aircraft barrage mortar was made (starting in 1942) at the Number 1 Army arsenal in Tokyo. As this arsenal already made 70mm mortar barrels for more conventional mortars, presumably the same facilities were used for the barrage mortar. The idea was that the mortar would discharge its projectile which, at its maximum ceiling would eject seven smaller projectiles. Connected to small parachutes these would detonate on enemy aircraft flying at low altitude. To be effective mass barrages would be needed but, despite the fairly widespread issue of the weapon, its use in its intended role was rather ad hoc. It seems that improvised platoons were its most common form of deployment. One such platoon in the Philippines had 31 men operating a mere five devices. What such an under-strength unit was supposed to achieve is anyone’s guess.

The mortar had a smoothbore barrel that was 48 inches long. The barrel was connected to a wooden block described in an American intelligence document of December 1943.

‘The base of the 70mm barrage mortar is a wooden block approximately 10 by 12 by 8 inches. Two bolts fasten a small base plate to the block. The wooden block absorbs the shock of firing and prevents the mortar from embedding itself in the ground’

A later American intelligence document, from March 1945 confirms much of what was written in the 1943 document,

‘The Japanese 70mm barrage mortar was first encountered on Attu. It consists of a smoothbore tube, 4 feet long, the steel plate of which is fastened by two bolts to a wooden block…’

The overall length is 75 inches. At the bottom of the wooden block is a long iron spike. The weapon is prepared and pointed toward the enemy aircraft by embedding this iron spike into the earth. Thus it can be seen that aiming was rather crudely done. The previously quoted document from 1943 simply says,

‘the 70mm or 81mm tube had no settings, controls or adjustments.’

This is a simple and, no doubt, cheaply made weapon. To fire the weapon the projectile was simply dropped down the barrel. If the round failed to fire the whole weapon would be slowly lifted up and gently tilted forwards to allow the round to slowly slide out. As for the projectile, it was as inventive as anything else devised during the war. It’s just a pity (at least for the IJA) that this inventiveness failed to find a better outlet. The same American intelligence document from December 1943 has a good description of the ammunition, presumably examples taken at Attu.

‘Ammunition for the 70mm barrage mortar is packed 10 to a box. The shell contains 7 parachute bombs 3 inches long by 11/16ths of an inch in diameter. A steel cylinder encases the whole assembly. The shell is painted black and is 11 9/16ths inches long and 2.34 inches in diameter. The nose is capped with a wooden disk. After the shell is projected from the mortar by the propelling charge in the base, a time train and fixed powder charge cause the projection of the seven smaller bombs borne by rice paper parachutes. At the same time a larger parachute is opened – tilting the main container and thus ensuring the scattering of the seven bombs.

These small bombs are loaded with three pellets of nitrostarch and are detonated in the air by a sensitive pull-igniter fuze with a phosphorus-coated string and delay element. They may also be used as an effective booby trap for any curious or unwary soldier.’

Again, the later American intelligence document from 1945 confirms much of the earlier intelligence document’s observations with one bonus – the 1945 document includes actual American test information.

‘Five rounds have been fired in a test, with the mortar malfunction of the delay train ignition (ed. – sadly, this is not elaborated on). The shells were quite noisy in flight and tumbled considerably, with the smoke of the black powder delay train clearly visible.

The releasing burst occurred in 7 to 8 seconds at altitudes of 1,520 to 1,660 feet and the shell cases hit the ground close to the firing position. All inert components of the round drifted to the ground within 30 seconds and the bombs drifted nearly half a mile, landing at intervals of about 30 yards.’

An example of a projectile for the barrage mortar that came up for sale some years ago (2007) was painted black with two white bands at the forward end and a red band at the other. The inside of the casing bottom still had some coiled fuse in place. The black painted projectile had a number of markings. On one side was a roughly applied area of white paint, almost a smudge, on which, in black, was the Kanji for ‘east’. The other side had a seven stage, top to bottom, series of Kanji symbols. While this is not an exact they, from top to bottom, translate as ‘seven, military measurement, together, launch, to block(?), to protect the fortress and bullet.’ As noted this may not be an exact translation. Other technical data differs from that already given. At least one modern claim says that the explosive component was RDX and the booster was lead azide. Of course, it’s very possible different types of explosive were used at different times.

It seems that the projectiles could also be fired more conventionally from the standard IJA model 11 70mm mortar. Though it is obscure as to what effect that tactic had on the battle field. Very oddly there is at least one eyewitness case of the barrage mortar being mounted in a Japanese bomber for defence against allied fighters.

The rice paper parachutes were around a foot in diameter, perhaps in some cases a bit larger. It is also clear that black powder could be used instead of the more usual ignition sources. As for maximum range, one American report gives the fairly unlikely number of 4,000 feet. Between 1,000 and 2,000 feet was far more realistic.

The blast radius, despite the small charge of the individual bomblets was around a 10 to 20 yards radius.

Stripping the 70mm barrage mortar was easy. First the barrel was unscrewed from the metal base plates, thus separating it from the wooden base block. The firing pin might then be removed from the fitting that holds it to the base plate. Finally the iron spike is removed from the wooden block.

On a last note, a May 1944 American intelligence report is fairly blunt about the weapon’s prospects in battle,

‘Although no instance has ever been reported of our aircraft being damaged with this weapon, it would appear that this weapon might be very effective against low flying aircraft if used in sufficient quantity.’

As previously noted however, these weapons tended to be used in penny packets. The fact that those issued with them sought to find other uses for the projectiles speaks for itself. In short the 70mm (and 81 mm) anti-aircraft barrage mortars must be considered interesting failures. Before those of British heritage become too smug however, a similar British project did catch the eye of Winston Churchill. Thankfully, cooler heads made sure it came to nothing.

Article by Rob Morgan.