#strange technology

• RP-3 (Tulip Rockets)

The RP-3 (from Rocket Projectile 3 inch) was a British rocket projectile used during and after the Second World War. Though primarily an air-to-ground weapon, it saw limited use in other roles.

The first use of rockets fired from aircraft was during World War I. The "unrotated projectiles" (UPs) were Le Prieur rockets which were mounted on the interplane struts of Nieuport fighters. These were used to attack observation balloons and were reasonably successful. With the war ended the Royal Air Force, intent on retrenching, forgot about firing rockets from aircraft. The British Army, however, did see a use for rockets against low-flying aircraft; from late 1940 parts of Britain were defended by increasing numbers of "Z-Batteries" 2-inch (51 mm) rockets supplementing the conventional anti-aircraft guns. When German forces under the command of Rommel intervened in the Western Desert from early 1941, it became clear that the Desert Air Force lacked weapons capable of damaging or destroying the large numbers of armoured fighting vehicles, particularly the heavier Panzer III and Panzer IV tanks possessed by the Germans. Consequently, in April 1941 Henry Tizard, the Chief Scientist, called together a panel to study "Methods of Attacking Armoured Vehicles."

The types of weapons investigated included the 40 mm Vickers S gun and related weapons manufactured by the Coventry Ordnance Works, as well as the Bofors 40 mm and the US 37 mm T9 cannon fitted to the Bell P-39 Airacobra: however, it was already recognised that these weapons were only capable of dealing with light tanks and motor transport, and using larger weapons on fighter-bombers was ruled out because of weight and difficulties handling recoil. Information was sought from the Soviets, who had just started using unguided RS-82 rockets against German ground forces in the opening phases of Operation Barbarossa. By September 1941 it was decided that two models of UP would be developed.

After consideration it was decided to concentrate on development of the 3-inch version, which could be developed from the 2-inch rocket used in the Z-Batteries. The rocket body was a steel tube 3 inches (76 mm) in diameter filled with 11 pounds (5.0 kg) of cordite propellant, fired electrically. The warhead was screwed into the forward end, and was initially a solid 25-pound (11 kg), 3.44-inch (87 mm) armor-piercing shell which was quickly supplemented by a 6-inch-diameter (150 mm), 60 pounds (27 kg) high-explosive head. Another type of head was a 25-pound (11 kg) mild steel (later concrete) practice head. Once the rocket had been mounted on the rails, an electrical lead was plugged into the exhaust of the rocket. Four large tailfins induced enough spin to stabilize the rocket, but as it was unguided, aiming was a matter of judgment and experience. Approach to the target needed to be precise, with no sideslip or yaw, which could throw the RP off line. Aircraft speed had to be precise at the moment of launch, and the angle of attack required precision. Trajectory drop was also a problem, especially at longer ranges. On the plus side the rocket was less complicated and more reliable than a gun firing a shell, and there was no recoil on firing. It was found to be a demoralising form of attack against ground troops, and the 60-pound warhead could be devastating. The rocket installations were light enough to be carried by single-seat fighters, giving them the punch of a cruiser.

Before the new weapon was released for service extensive tests were carried out by the Instrument, Armament and Defence Flight (IADF) at Royal Aircraft Establishment, Farnborough. Hurricanes were fitted with rockets and rails and flown during June and July 1942. Further tests were undertaken from September 28th to November 30th to develop rocket firing tactics. Other aircraft used were a Hudson, a Swordfish, and a Sea Hurricane. Aiming was through a standard GM.II reflector gunsight. A later modification enabled the reflector to be tilted with the aid of a graduated scale, depressing the line of sight, the GM.IIL. The first operational use of the RP was in the Western Desert as a "tank-busting" weapon on Hawker Hurricane Mk. IIEs and IVs. The 25-pound armour-piercing heads were found to be ineffective against the Tiger I tanks coming into German service. With the example of the success of Royal Artillery gunners using high-explosive shells from the 25 pdr gun-howitzer, it was decided to design a new 60-pound semi-armour-piercing (SAP) head. These were capable of knocking turrets off tanks. A typical RP-3 installation was 4 projectiles on launching rails under each wing. A selector switch was fitted to allow the pilot to fire them singly (later omitted), in pairs, or as a full salvo. Towards the end of the war some RAF Second Tactical Air Force Hawker Typhoons had their installation adapted to carry an additional four rockets.

Possibly the best known action involving RP-3s was that of the Falaise pocket of mid-August 1944. During the battle German forces, retreating to avoid being trapped in a pincer movement by Allied ground forces, came under air attack. Amongst the waves of light, medium and fighter bombers attacking the German columns the Typhoons of 2 TAF attacked with their rockets, claiming hundreds of tanks and "mechanised enemy transport". After the battle Army and 2nd TAF Operational Research Sections studying the battleground came to the conclusion that far fewer vehicles (17 in total) had been destroyed by rocket strike alone. What was clear was that in the heat of battle it was far harder for pilots to launch the weapons while meeting the conditions needed for accuracy.

In 1945, some British Shermans were fitted with two or four rails – one or two either side of the turret – to carry 60-pound headed rockets. These were used at the Rhine Crossing by tanks of the 1st Coldstream Guards. The tanks were called "Sherman Tulips". The tanks fitted included both conventional Shermans and the more heavily armed Sherman Fireflies. The modifications were first tried out by two officers of the 1st Armoured Battalion, Coldstream Guards, 5th Guards Armoured Brigade, who obtained rockets and launching rails from an RAF base and carried out the first test firings on March 17th, 1945. They were inspired after hearing the idea had been earlier tried, but abandoned, by a Canadian unit, the 18th Armoured Car Regiment (12th Manitoba Dragoons), who had fitted RP-3 rails to a Staghound Armoured Car. The rockets were highly inaccurate when fired from a tank as they were being fired from a stationary point and had little slipstream over the fins. Despite this, the RP-3 was valued by tank crews for the destructive effect of its 60-pound warhead. In combat, they were also used for short-range, saturation bombardment of an area and were effective as an immediate counter to German ambushes.

• Fu-Go Balloon Bomb

A Fu-Go, or fire balloon (風船爆弾, fūsen bakudan, lit. "balloon bomb"), was a weapon launched by Japan during World War II.

The fūsen bakudan campaign was the most earnest of the attacks. The concept was the brainchild of the Imperial Japanese Army's Ninth Army's Number Nine Research Laboratory, under Major General Sueyoshi Kusaba, with work performed by Technical Major Teiji Takada and his colleagues. The balloons were intended to make use of a strong current of winter air that the Japanese had discovered flowing at high altitude and speed over their country, which later became known as the jet stream. The jet stream reported by Wasaburo Oishi blew at altitudes above 30,000 ft (9.1 km) and could carry a large balloon across the Pacific in three days, over a distance of more than 5,000 miles (8,000 km). Such balloons could carry incendiary and high-explosive bombs to the United States and drop them there to kill people, destroy buildings, and start forest fires. The preparations were lengthy because the technological problems were acute. A hydrogen balloon expands when warmed by the sunlight, and rises; then it contracts when cooled at night, and descends. The engineers devised a control system driven by an altimeter to discard ballast. When the balloon descended below 30,000 ft (9.1 km), it electrically fired a charge to cut loose sandbags. The sandbags were carried on a cast-aluminium four-spoked wheel and discarded two at a time to keep the wheel balanced. Similarly, when the balloon rose above about 38,000 feet (12 km), the altimeter activated a valve to vent hydrogen. The hydrogen was also vented if the balloon's pressure reached a critical level.

The control system ran the balloon through three days of flight. By that time, it was likely over the U.S., and its ballast was expended. The final flash of gunpowder released the bombs, also carried on the wheel, and lit a 64 feet (20 meters) long fuse that hung from the balloon's equator. After 84 minutes, the fuse fired a flash bomb that destroyed the balloon. The balloon had to carry about 1,001 pounds (454 kg) of gear. At first the balloons were made of conventional rubberized silk, but improved envelopes had less leakage. An order went out for ten thousand balloons made of "washi", a paper derived from mulberry bushes that was impermeable and very tough. It was only available in squares about the size of a road map, so it was glued together in three or four laminations using edible konnyaku (devil's tongue) paste – though hungry workers stealing the paste for food created some problems. Many workers were nimble-fingered teenaged school girls.

The bombs most commonly carried by the balloons were, Type 92 33-pound (15 kg) high-explosive bomb consisting of 9.5 pounds (4.3 kg) picric acid or TNT surrounded by 26 steel rings within a steel casing 4 inches (10 cm) in diameter and 14.5 inches (37 cm) long and welded to a 11-inch (28 cm) tail fin assembly. Type 97 26-pound (12 kg) thermite incendiary bomb using the Type 92 bomb casing and fin assembly containing 11 ounces (310 g) of gunpowder and three 3.3-pound (1.5 kg) magnesium containers of thermite. 11-pound (5.0 kg) thermite incendiary bomb consisting of a 3.75-inch (9.5 cm) steel tube 15.75 inches (40.0 cm) long containing thermite with an ignition charge of magnesium, potassium nitrate and barium peroxide.

A balloon launch organization of three battalions was formed. The first battalion included headquarters and three squadrons totaling 1,500 men in Ibaraki Prefecture with nine launch stations at Ōtsu. The second battalion of 700 men in three squadrons operated six launch stations at Ichinomiya, Chiba; and the third battalion of 600 men in two squadrons operated six launch stations at Nakoso in Fukushima Prefecture. The Ōtsu site included hydrogen gas generating facilities, but the 2nd and 3rd battalion launch sites used hydrogen manufactured elsewhere. The best time to launch was just after the passing of a high-pressure front, and wind conditions were most suitable for several hours prior to the onshore breezes at sunrise. The combined launch capacity of all three battalions was about 200 balloons per day. Initial tests took place in September 1944 and proved satisfactory; however, before preparations were complete, United States Army Air Forces B-29 Superfortress planes began bombing the Japanese home islands. The attacks were somewhat ineffectual at first but still fueled the desire for revenge sparked by the Doolittle Raid. The first balloon was released on November 3rd, 1944. The Japanese chose to launch the campaign in November; because the period of maximum jet stream velocity is November through March. This limited the chance of the incendiary bombs causing forest fires, as that time of year produces the maximum North American Pacific coastal precipitation, and forests were generally snow-covered or too damp to catch fire easily. On November 4th, 1944, a United States Navy patrol craft discovered one of the first radiosonde balloons floating off San Pedro, Los Angeles. National and state agencies were placed on heightened alert status when balloons were found in Wyoming and Montana before the end of November.

The balloons continued to arrive in Alaska, Hawaii, Oregon, Kansas, Iowa, Washington, Idaho, South Dakota, and Nevada (including one that landed near Yerington that was discovered by cowboys who cut it up and used it as a hay tarp. Balloons were discovered as well in Canada in British Columbia, Saskatchewan, Manitoba, Alberta, the Yukon, and Northwest Territories. Army Air Forces or Navy fighters scrambled to intercept the balloons, but they had little success; the balloons flew very high and surprisingly fast, and fighters destroyed fewer than 20. American authorities concluded the greatest danger from these balloons would be wildfires in the Pacific coastal forests. The Fourth Air Force, Western Defense Command, and Ninth Service Command organized the Firefly Project of 2,700 troops, including 200 paratroopers of the 555th Parachute Infantry Battalion with Stinson L-5 Sentinel and Douglas C-47 Skytrain aircraft. These men were stationed at critical points for use in fire-fighting missions. The 555th suffered one fatality and 22 injuries fighting fires. Through Firefly, the military used the United States Forest Service as a proxy agency to combat FuGo. Due to limited wartime fire suppression personnel, Firefly relied upon the 555th as well as conscientious objectors.

By early 1945, Americans were becoming aware that something strange was going on. Balloons had been sighted and explosions heard, from California to Alaska. Something that appeared to witnesses to be like a parachute descended over Thermopolis, Wyoming. A fragmentation bomb exploded, and shrapnel was found around the crater. On March 10th, 1945, one of the last paper balloons descended in the vicinity of the Manhattan Project's production facility at the Hanford Site. This balloon caused a short circuit in the power lines supplying electricity for the nuclear reactor cooling pumps, but backup safety devices restored power almost immediately. Japanese propaganda broadcasts announced great fires and an American public in panic, declaring casualties in the thousands. With no evidence of any effect, General Kusaba was ordered to cease operations in April 1945, believing that the mission had been a total fiasco. The expense was large, and in the meantime the B-29s had destroyed two of the three hydrogen plants needed by the project. On May 5th, 1945, a pregnant woman and five children were killed when they discovered a balloon bomb that had landed in the forest of Gearhart Mountain in Southern Oregon. Military personnel arrived on the scene within hours, and saw that the balloon still had snow underneath it, while the surrounding area did not. They concluded that the balloon bomb had drifted to the ground several weeks earlier, and had lain there undisturbed until found by the group.

• Messerschmitt Me 323 Gigant

The Messerschmitt Me 323 Gigant ("Giant") was a German military transport aircraft of World War II. It was a powered variant of the Me 321 military glider and was the largest land-based transport aircraft of the war. A total of 213 are recorded as having been made, a few being converted from the Me 321.

The Me 323 was the result of a 1940 German requirement for a large assault glider in preparation for Operation Sea Lion, the projected invasion of Great Britain. The DFS 230 light glider had already proven its worth in the Battle of Fort Eben-Emael in Belgium (the first ever assault by gliderborne troops), and would later be used successfully in the invasion of Crete in 1941. However, in order to mount an invasion across the English Channel, the Germans would need to be able to airlift vehicles and other heavy equipment as part of an initial assault wave. Although Operation Sea Lion was cancelled, the requirement for a heavy air transport capability still existed, with the focus now on the forthcoming Operation Barbarossa, the invasion of the Soviet Union.

On October 18th, 1940, Junkers and Messerschmitt were given just 14 days to submit a proposal for a large transport glider. The emphasis was still very much on the assault role: the ambitious requirement was to be able to carry either an 88 mm gun and its half-track tractor, or a Panzer IV medium tank. The proposed Messerschmitt aircraft was originally designated Me 261w, then changed to Me 263 and eventually became the Me 321. Although the Me 321 saw considerable service in Russia as a transport, it was never used for its intended role as an assault glider.

Early in 1941, as a result of feedback from Transport Command pilots in Russia, the decision was taken to produce a motorized variant of the Me 321, to be designated Me 323. It was decided to use French Gnome et Rhône GR14N radial engines for take-off as used in the Bloch MB.175 aircraft; using French engines was thought to place no burden on Germany's overstrained industry. The four-engined Me 323C was considered merely a stepping stone to the six-engined D series; it still required the five-engined Heinkel He 111Z Zwilling or the highly dangerous, "vic-style" Troika-Schlepp formation of three Messerschmitt Bf 110 heavy fighters and underwing-mounted Walter HWK 109-500 Starthilfe rocket assisted takeoff units to get airborne when fully loaded, but it could return to base under its own power when empty.

Some Me 321s were converted to Me 323s, but the majority were built as six-engine aircraft from the beginning; early models were fitted with wooden two-blade propellers, which were later replaced by metal, three-blade variable-pitch versions. The Me 323 had a maximum speed of only 219 km/h (136 mph) at sea level and speed dropped with altitude. For defensive armament, it was armed with five 13 mm (.51 in) MG 131 machine guns firing from a dorsal position behind the wings and from the fuselage. An inherent advantage to the Me 323 was its ability to withstand a great deal of punishment from machine gun fire thanks to its large wooden structure - only the engines, cockpit and fuel stores were large critical areas that could render the aircraft uncontrollable. However, the lack of agility for the Me 323 meant that the pilot could not enact some sort of helpful defensive maneuver to avoid enemy attack.

• Barrage Balloon

A barrage balloon is a large tethered kite balloon used to defend ground targets against aircraft attack, by raising aloft steel cables which pose a severe collision risk to aircraft, making the attacker's approach more difficult. The design of the kite balloon, having a shape and cable bridling which stabilise the balloon and reduce drag, meant that it could be operated in higher wind conditions than a spherical balloon. Some examples carried small explosive charges that would be pulled up against the aircraft to ensure its destruction. Barrage balloons are not practical against very high altitude flying aircraft, due to the weight of the long cable required.

In 1938 the British Balloon Command was established to protect cities and key targets such as industrial areas, ports and harbours. Balloons were intended to defend against dive bombers flying at heights up to 5,000 feet (1,500 m), forcing them to fly higher and into the range of concentrated anti-aircraft fire—anti-aircraft guns could not traverse fast enough to attack aircraft flying at low altitude and high speed. By the middle of 1940 there were 1,400 balloons, a third of them over the London area.

Balloons proved to be of little use against the German high-level bombers with which the dive-bombers were replaced, but continued to be manufactured nonetheless, until there were almost 3,000 in 1944. They proved to be mildly effective against the V-1 flying bomb, which usually flew at 2,000 feet (600 m) or lower but had wire-cutters on its wings to counter balloons. 231 V-1s are officially claimed to have been destroyed by balloons.