Monday, February 28, 2011

Mangonel: type of catapult or siege machine used to throw projectiles at a castle's walls

A mangonel (derived from Greco-Latin word manganon, meaning "engine of war")was a type of catapult or siege machine used in the medieval period to throw projectiles at a castle's walls. The exact meaning of the term is debatable, and several possibilities have been suggested. It may have been a name for counterweight artillery (trebuchets), possibly either a men assisted fixed-counterweight type, or one with a particular type of frame. The Arabic term manajaniq comes from the same word, and applies to various kinds of trebuchet. It is also possible that it referred to more than one kind of engine, in different times or places, or was a general term. For this use see trebuchet.

In modern parlance catapult is often used as the name of a Medieval form of onager, though there is little evidence for this historically. In this sense, mangonel had poorer accuracy than a trebuchet (which was introduced later, shortly before the discovery and widespread usage of gunpowder). The mangonel threw projectiles on a lower trajectory and at a higher velocity than the trebuchet with the intention of destroying walls, rather than hurling projectiles over them. It was more suited to field battles.

A simple illustration of an ancient catapult

Mangonels shot heavy projectiles from a bowl-shaped bucket at the end of the arm. The bucket could launch more rocks than a sling; this made it different from an onager. The sling was changed to a bucket for more force when firing. In combat, mangonels hurled rocks, burning objects (fire pots, vessels filled with flammable materials that created a fireball on impact), or anything else readily available to the attacking and defending forces. The more unusual types of projectile included dead (and often partially decomposed) carcasses of animals or people (and even human heads), used to intimidate, demoralize, and spread disease among the besieged. This tactic often proved effective. The short supply of food, which was often of low quality or rotting, combined with the cramped living space of the defenders, poor hygiene, and vermin infestations provided an ideal scenario for the spread of disease. It should be noted, however, that the mangonel's principal role in battle, particularly medieval battle, was to knock down a castle or city's walls and infrastructure, not to kill troops. Its unpredictable, yet powerful strikes were best suited to hitting broad, non-moving targets such as buildings or walls.

Side view of a mangonel

The mangonel in the Middle Ages had a different connotation from the roman Onager, it was more likely a fixed counter-weight siege engine similar to a trebuchet, its only difference from a trebuchet was its fixed counter-weight which was pulled down by several men, this way, with trained workers, the leader of the craft could adjust the strength applied to the mangonel.

Medieval Mangonel

The mangonel was loaded by lowering a rope with a hook at its end, this hook was tied to another rope connected to a "pulling" system (this could be a Pulley compound, a Gear compound, or even an animal traction system) to pull the rope and lower the main rod. Once the rod was lowered a few workers were responsible for the attachment of a sling where the projectile is placed. When the mangonel was loaded the leader gave the order to release the main rod, and at the same time several men (usually around 20) pulled the ropes attached to the counter-weight.

If the crew was well trained, it was possible to control whether the projectile traveled in a low or high trajectory, but if the crew was not well trained then existed the risk of the projectile killing friendly troops or even the crew itself.

Friday, February 25, 2011

Ingram Model 6 submachine gun

Gordon Ingram designed his first prototype submachine gun during late 1940s; soon after his first prototype he produced next design, known as Model 6. This gun was manufactured by American company Police Ordnance Co between 1949 and 1952; about 15 to 20 thousands of Model 6 submachine guns were made and sold to Cuban Navy, Peruvian Army and some US Police departments. In about 1952 Ingram also designed an improved version of the Model 6, known as Model 7. This weapon was externally similar to Model 6 but fired from closed bolt, and had a separate fire mode selector. Very few Model 7 submachine guns were produced.

Ingram M6 (model 6) submachine gun in "Military" configuration, left side.

Ingram Model 6 submachine guns were produced in two basic configurations, "Military" and "Police". The "Military" version had plain wooden forearm, plain barrel and protected front sight. It also was capable to mount a proprietary spike-shaped bayonet, which was stored inside the forearm in reversed position when not required. "Police" version of Model 6 featured a front foregrip similar to that of Thompson submachine gun, and a partially finned barrel.

Ingram M6 (model 6) submachine gun in "Military" configuration, right side.

Ingram Model 6 submachine gun is blowback operated, selective fired weapon that fired from open bolt. The only safety provided was the locking notch in the cocking handle slot, which was used to lock the bolt by its handle in cocked (retracted) position. Selection of mode of fire was made by the pull of the trigger - short pull produced single shots, and long pull produced full automatic fire.

Ingram M6 (model 6) submachine gun in "Police" configuration, left side.

Ingram M7 (model 7) submachine gun in "Police" configuration, right side. Note the small fire mode selector switch visible just above the trigger guard.

Caliber: 9x19mm, .38 Super and .45 ACP
Weight: ~3,3 kg empty
Length: 762 mm
Barrel length: 228 mm
Rate of fire: 600 rounds per minute
Magazine capacity: 30 rounds
Effective range: 100 meters

Thursday, February 24, 2011

Trebuchet: a siege engine employed in the Middle Ages

A trebuchet (from the French trébuchet) is a siege engine that was employed in the Middle Ages. It is sometimes called a "counterweight trebuchet" or "counterpoise trebuchet" in order to distinguish it from an earlier weapon that has come to be called the "traction trebuchet", the original version with pulling men instead of a counterweight. Man-powered trebuchets appeared in the Greek world and China in about the 4th century BC.

Counterweight trebuchet constructed on the design of the "Warwolf".

The counterweight trebuchet appeared in both Christian and Muslim lands around the Mediterranean in the twelfth century. It could fling projectiles of up to three hundred and fifty pounds (140 kg) at high speeds into enemy fortifications. Occasionally, disease-infected corpses were flung into cities in an attempt to infect and terrorize the people under siege, a medieval form of biological warfare.

The trebuchet did not become obsolete until the 13th century, well after the introduction of gunpowder. Trebuchets were far more accurate than other medieval catapults.

11th century chronicle depicting a Byzantine siege.

A trebuchet is a type of catapult that works by using the energy of a raised counterweight to throw the projectile. Initially, the sling, which has a pouch containing the projectile, is placed in a trough below the axle, which supports the beam. Upon releasing the trigger, the sling and the beam swing around toward the vertical position, where one end of the sling releases, opening the pouch and propelling the projectile towards the target. The efficiency of the transfer of the stored energy of the counterweight to the projectile can be quite high, even without, for example, restraining the path of the counterweight.

Modern day enthusiasts have varied the original design, especially to control the path of the counterweight.

The trebuchet is often confused with the earlier torsion siege engines. The main difference is that a torsion siege engine (examples of which include the onager and ballista) uses a twisted rope or twine to provide power, whereas a trebuchet uses a counterweight, usually much closer to the fulcrum than the payload for mechanical advantage, though this is not necessary. A trebuchet also has a sling holding the projectile (although the Roman onager often had a sling as well), and a means for releasing it at the right moment for maximum range. Both trebuchets and torsion siege engines are classified under the generic term "catapult", which includes any non-handheld mechanical device designed to hurl an object.

Counterweight trebuchet by the German engineer Konrad Kyeser (ca. 1405).

The trebuchet derives from the ancient sling. A variation of the sling, called staff sling (Latin: fustibalus), contained a short piece of wood to extend the arm and provide greater leverage. This evolved into the traction trebuchet in which a number of people pull on ropes attached to the short arm of a lever that has a sling on the long arm. This type of trebuchet is smaller and has a shorter range, but is a more portable machine and has a faster rate of fire than larger, counterweight-powered types. The smallest traction trebuchets could be powered by the weight and pulling strength of one person using a single rope, but most were designed and sized for between 15 and 45 men, generally two per rope. These teams would sometimes be local citizens helping in the siege or in the defense of their town. Traction trebuchets had a range of 100 to 200 feet (30 to 61 m) when casting weights up to 250 pounds. It is believed that the first traction trebuchets were used by the Mohists in China as early as in the 5th century BC descriptions of which can be found in the Mojing (compiled in the 4th century BC). The Chinese named the later counterweight trebuchet Huihui Pao (Muslim Weapons, "huihui" means Muslim) or Xiangyang Pao (襄陽砲), where Pao means bombard.

The traction trebuchet next appeared in Byzantium. The Strategikon of Emperor Maurice, composed in the late 6th century, calls for "ballistae revolving in both directions," (Βαλλίστρας έκατηρωθεν στρεφόμενας), probably traction trebuchets (Dennis 1998, p. 99). The Miracles of St. Demetrius, composed by John I, archbishop of Thessalonike, clearly describe traction trebuchets in the Avaro-Slav artillery: "Hanging from the back sides of these pieces of timber were slings and from the front strong ropes, by which, pulling down and releasing the sling, they propel the stones up high and with a loud noise." (John I 597 1:154, ed. Lemerle 1979).

A strobe picture of a simulated trebuchet in action.

They were also used with great effect by the Islamic armies during the Muslim conquests. A surviving Arab technical treatise on these machines is Kitab Aniq fi al-Manajaniq ( كتاب أنيق في المنجنيق, An Elegant Book on Trebuchets), written in 1462 by Yusuf ibn Urunbugha al-Zaradkash. It provides detailed construction and operating information.

There is some doubt as to the exact period in which traction trebuchets, or knowledge of them, reached Scandinavia. The Vikings may have known of them at a very early stage, as the monk Abbo de St. Germain reports on the siege of Paris in his epic De bello Parisiaco dated about 890 that engines of war were used. Another source mentions that Nordic people or "the Norsemen" used engines of war at the siege of Angers as early as 873.

Counterweight trebuchet at Château des Baux, France.

The hand-trebuchet (Greek: cheiromangana) was a staff sling mounted on a pole using a lever mechanism to propel projectiles. Basically a portable trebuchet which could be operated by a single man, it was used by emperor Nikephoros II Phokas around 965 to disrupt enemy formations in the open field. It was also mentioned in the Taktika of general Nikephoros Ouranos (ca. 1000), and listed in the Anonymus De obsidione toleranda as a form of artillery.

19th century French three-quarter drawing of a medieval counterweight trebuchet.

The earliest written record of the counterweight trebuchet, much more powerful than the traction version, appears in the work of the 12th century Byzantine historian Niketas Choniates. Niketas describes a trebuchet used by Andronikos I Komnenos, future Byzantine emperor, at the siege of Zevgminon in 1165 which was equipped with a windlass, an apparatus which was required neither for traction nor hybrid trebuchets to launch missiles. Chevedden dates the invention of the new artillery type back to the Siege of Nicaea in 1097 when the Byzantine emperor Alexios I Komnenos, an ally of the besieging crusaders, was reported to have invented new pieces of heavy artillery which deviated from the conventional design and made a deep impression on everyone.

The dramatic increase in military performance is for the first time reflected in historical records on the occasion of the second siege of Tyre in 1124, when the crusaders reportedly made use of "great trebuchets". By the 1120–30s, the counterweight trebuchet had diffused not only to the crusaders states, but probably also westwards to the Normans of Sicily and eastwards to the Great Seljuqs. The military use of the new gravity-powered artillery culminated in the 12th century during the Siege of Acre (1189–91) which saw the kings Richard I of England and Philip II of France wrestle for control of the city with Saladin's forces.

Trebuchets at Château de Castelnaud.

The only pictorial evidence of a counterweight trebuchet in the 12th century comes from an Islamic scholar, Mardi bin Ali al-Tarsusi, who wrote a military manual for Saladin circa 1187 based on information collected from an Armenian weapon expert in Muslim service. He describes a hybrid trebuchet that he said had the same hurling power as a traction machine pulled by fifty men due to "the constant force [of gravity], whereas men differ in their pulling force." (Showing his mechanical proficiency, Tarsusi designed his trebuchet so that as it was fired it cocked a supplementary crossbow, probably to protect the engineers from attack.) He allegedly wrote "Trebuchets are machines invented by unbelieving devils." (Al-Tarsusi, Bodleian MS 264). This suggests that by the time of Saladin, Muslims were acquainted with counterweight engines, but did not believe that they had invented these machines.

During the Crusades, Philip II of France named two of the trebuchets he used in the Siege of Acre in 1191 "God's Stone-Thrower" and "Bad Neighbor." During a siege of Stirling Castle in 1304, Edward Longshanks ordered his engineers to make a giant trebuchet for the English army, named "Warwolf". Range and size of the weapons varied. In 1421 the future Charles VII of France commissioned a trebuchet (coyllar) that could shoot a stone of 800 kg, while in 1188 at Ashyun, rocks up to 1,500 kg were used. Average weight of the projectiles was probably around 50–100 kg, with a range of ca. 300 meters. Rate of fire could be noteworthy: at the siege of Lisbon (1147), two engines were capable of launching a stone every 15 seconds. Also human corpses could be used in special occasion: in 1422 Prince Korybut, for example, in the siege of Karlštejn Castle shot men and manure within the enemy walls, apparently managing to spread infection among the defenders. The largest trebuchets needed exceptional quantities of timber: at the Siege of Damietta, in 1249, Louis IX of France was able to build a stockade for the whole Crusade camp with the wood from 24 captured Egyptian trebuchets.

Counterweight trebuchets do not appear with certainty in Chinese historical records until about 1268, when the Mongols laid siege to Fancheng and Xiangyang. At the Siege of Fancheng and Xiangyang, the Mongol army, unable to capture the cities despite besieging the Song defenders for years, brought in two Persian engineers who built hinged counterweight trebuchets and soon reduced the cities to rubble, forcing the surrender of the garrison. These engines were called by the Chinese historians the Huihui Pao (回回砲)("huihui" means Muslim) or Xiangyang Pao (襄陽砲), because they were first encountered in that battle. Recent research by Paul E. Chevedden indicates that the hui-hui pao was actually a European design, a double-counterweight engine that had been introduced to the Levant by Holy Roman Emperor Frederick II (1210–1250) only shortly before. The Muslim historian Rashid-al-Din Hamadani (1247?–1318) refers in his universal history to the Mongol trebuchets used at the Song cities as "Frankish" or "European trebuchets" ("manjaniq ifranji" or "manjaniq firanji"):

Side view of counterweight trebuchet.

Before that there had not been any large Frankish catapult in Cathay [i.e. China], but Talib, a catapult-maker from this land, had gone to Baalbek and Damascus, and his sons Abubakr, Ibrahim, and Muhammad, and his employees made seven large catapults and set out to conquer the city [Sayan Fu or Hsiang-yang fu = modern Xiangfan].

With the introduction of gunpowder, the trebuchet lost its place as the siege engine of choice to the cannon. Trebuchets were used both at the siege of Burgos (1475–1476) and siege of Rhodes (1480). One of the last recorded military uses was by Hernán Cortés, at the 1521 siege of the Aztec capital Tenochtitlán. Accounts of the attack note that its use was motivated by the limited supply of gunpowder. The attempt was reportedly unsuccessful: the first projectile landed on the trebuchet itself, destroying it.

In 1779, British forces defending Gibraltar, finding that their cannons were unable to fire far enough for some purposes, constructed a trebuchet. It is unknown how successful this was: the Spanish attackers were eventually defeated, but this was largely due to a sortie.

Medieval traction trebuchet next to a staff slinger.

Tuesday, February 22, 2011

Submachine gun: Reising M-50 and M-55

The Reising submachine gun was designed by American Eugene Reising and patented in 1940. Production of the new submachine gun commenced in 1941 at Harrington & Richardson (H&R) arms factory. In 1942, US Marine Corps signed first contract for delivery of Reising M50 submachine guns, and several tents of thousands of Reising M50 SMG's were delivered to USMC during the war. It must be noted that USMC weapons were slightly different in appearance from original version, having different trigger guard, larger takedown screw head, and other minor changes. Similar weapons were sold to various US agencies to guard military facilities and other important locations in USA. For USMC paratroopers and tankers H&R produced a folding-stock version, known as Reising M55. H&R also produced a semi-automatic only version of the M50, known as M60, which was used for training and guard purposes. The least known version is the Reising M65, a training semi-automatic weapon chambered for .22LR ammunition. It must be noted that US Marines generally disliked the Reising gun for its poor reliability, especially when gun was fouled or dirty. However, it was quite accurate and sufficiently reliable in "urban" conditions, so many Reising submachine guns were used by various US Police departments through several post-war decades.

Early production ReisingM50 submachine gun, so called "commercial" or "police" model, with20-round magazine.
Late production ReisingM50 submachine gun, "military" model.

Reising M50 submachine gun is delayed blowback operated, selective fired weapon. It fired from closed bolt and has a separate striker (non-pivoting, sliding hammer) which hit the firing pin when gun was discharged. The delay for opening movement of the bolt was provided by displacing its rear upper edge from the recesses, made on the inside of the receiver. The fire mode selector was located at the right side of the receiver, in front of the rear sight. Charging handle was unusually located in the slot, formed on the underside of the stock, in front of the magazine. To cock the gun, shooter must insert his finger into the slot and pull the cocking handle back, and then release it. Feed was from box magazines; standard magazine capacity was 20 rounds, with cartridges held in double stack and with single position feed. For training purposes, H&R also produced 12-round single stack magazines. Currently, aftermarket 30-round magazines are available for all .45 caliber Reising weapons. Sights included front post and a diopter rear, adjustable from 50 to 300 yards range. Original M50 submachine guns featured an one-piece wooden stock and a muzzle flip compensator. "Paratrooper" Reising M55 guns had wooden stocks with pistol grip and side-folding stocks made from steel wire, and no muzzle compensators. Both types of submachine gun featured partially finned barrels. Semi-automatic only Reising M60 carbines featured longer barrels with no fins.

ReisingM55 submachine gun, with shoulder stock folded.

Reising M60semiautomatic carbine.

Reising M50 Reising M55
Caliber .45 ACP
Weight 3,06 kg empty 2,81 kg empty
Length (stock closed/open) 857 mm 556 / 781 mm
Barrel length 279 mm 263 mm
Rate offire 550 roundsper minute 500rounds per minute
Magazinecapacity 12 or 20 rounds 12 or 20 rounds
Effective range 100 meters 100 meters

Ingram MAC Model 10 / M10 & Model 11 / M11 submachine guns

Gordon B. Ingram, an American arms designer who previously developed several submachine guns under his own name (such as Ingram Model 6), began work on a more compact submachine gun, suitable for clandestine operations, in around 1964. Several prototypes were made by Ingram by 1965, and in 1966 at least one prototype gun was purchased by US Army for test and evaluation. In around 1969 Ingram joined the Sionics Co, which previously manufactured silencers for small arms, and company started tooling up to produce Ingram submachine guns. In 1970 the Sionics was incorporated into larger company Military Armament Corporation (or MAC in short), located in Powder Springs, GA, USA. The same year MAC company commenced production of two versions of Ingram submachine guns - the larger Model 10 (M10), chambered for 9x19 or .45ACP ammunition, and smaller Model 11 (M11), chambered for 9x17 (9mm Short or .380ACP). Either version was available with silencers, developed by Sionics / MAC. The MAC ceased its functioning in 1976, and manufacturing rights for Ingram M10 and M11 submachine guns were transferred to RPB Industries Inc, located in Atlanta, CA. later on, submachine guns and semi-automatic only "pistols" and carbines, based on Ingram design, were manufactured by several more companies, such as SWD Inc, Cobray, and others. Copies of M10 were manufactured in Taiwan and Japan. Original weapons were sold to Chile and Yugoslavia during early 1970s; later on, sales were made to some Asian and South American countries.

 Ingram M10 in 9x19mm caliber, as made by MAC, with stock retracted.

Ingram Model 10 and Model 11 submachine guns were intended for close encounters and for concealed carry. Several versions of M10 were made with longer barrels, including rare "carbine" version with barrel being about 450mm (18") long, and partially enclosed into perforated barrel jacket. The "civilian" clones of Ingram models were made in a great variety of modifications, with minor differences in almost every detail. Cobray 9mm M11 "pistols", for example, were based on experimental submachine guns developed at RPB Indusries in around 1979; these guns had longer receivers necessary to increase the bolt travel and thus decrease the rate of fire; in semi-automatic versions this feature is, obviously, irrelevant.

Ingram M10 in .45ACP caliber, as made by MAC, with stock extended.

Ingram Model 10 is blowback-operated, selective-fire submachine gun, that fires from open bolt. The bolt has firing pin milled in its body (or pinned to it). Bolt is of telescoped design, with most of its weight located in front of the breech face, around the barrel. Cocking handle is located at the top of the gun, and can be used to lock the bolt in forward position, when handle is turned sideways by 90 degrees. The receiver is made from formed sheet steel and consist of two parts - upper and lower. Receiver parts are connected by steel pin at the front of the weapon. Charging handle is located at the top of the receiver and doesn't move with the bolt when firing. The muzzle of the barrel is threaded to accept silencer. Controls include a manual safety, made in the form of a slider located inside the trigger guard, and a separate fire mode selector, made in form of a rotary lever located on left side of weapon, above the front of trigger guard. The shoulder stock was of telescoped design with folding shoulder rest made of steel wire. To provide additional stability, a leather loop attached to the front of the receiver, which is used to hold the gun by non-firing hand.

Ingram M11 in 9mm Short (9x17, .380ACP) caliber, as made by RPB Industries, with 16-round magazine.

Sights are mostly simple types, and include non-adjustable diopter type rear and protected front blade.

 Ingram M11 in 9mm Short, with installed silencer.

 Ingram M10 in "carbine version" with extended barrel and modified shoulder stock.

 Cobray M11 "pistol" in 9x19mm - one of semi-automatic clones made to Ingram M10 pattern; note longer receiver and lack of fire mode selector switch.

  Ingram M10 Ingram M11
Caliber  .45ACP and 9x19 Luger 9x17 Browning Short (.380ACP)
Weight  2,84 kg empty 1,59 kg empty
Length 269 / 548 mm 222 / 460 mm
Barrel length 146 mm  129 mm
Rate of fire 1145 (.45) / 1090 (9mm) rounds per minute 1200 rounds per minute
Magazine capacity  30 (.45) or 32 (9mm) rounds 16 or 32 rounds
Effective range  50-70 meters 30-50 meters

Saturday, February 19, 2011

The First Zeppelins of Count Ferdinand von Zeppelin

The construction of Count Ferdinand von Zeppelin’s first airship, LZ-1, began in June, 1898 in a floating wooden hangar on the Bodensee (Lake Constance) at Manzell (Friedrichshafen) in Southern Germany, not far from the Swiss border. The movable, floating shed allowed the ship to be positioned into the wind to enter or leave its hangar.

LZ-1 in its floating shed on the Bodensee.

The ship was completed in the winter of 1899, but Count von Zeppelin decided to wait until the summer of 1900 before attempting to fly his invention. The ship was inflated with hydrogen gas in June, and made its maiden flight on July 2, 1900. The first flight lasted about 18 minutes and covered about 3-1/2 miles over the lake.

LZ-1 (Luftschiff Zeppelin 1) was 420 feet long, 38-1/2 feet in diameter, and contained approximately 399,000 cubic feet of hydrogen in 17 gas cells made of rubberized cotton fabric. Two metal gondolas were suspended below the ship (one forward and one aft) and each gondola housed a 4-cylinder water-cooled Daimler gasoline engine producing about 14 horsepower. Each engine was connected by long shafts to two outrigger propellers mounted on either side of the hull. Pitch was controlled by a sliding weight suspended under the hull which could be shifted fore and aft; there were no elevators for pitch control, or fins for stability.

Luftschiff Zeppelin 1.

The first flight of LZ-1 was the culmination of years of planning by Count Zeppelin, but as a first attempt the ship had understandable weaknesses: LZ-1 was overweight, and a severe lack of engine power and speed made it difficult to control in even slight winds; the engines themselves were unreliable, and one failed during the short maiden flight; the ship suffered from poor controllability due to its lack of horizontal or vertical stabilizing fins and control surfaces, and the sliding weight system jammed, eliminating pitch control; and most importantly, the structure itself lacked rigidity due to its weak tubular frame, which hogged during flight, with its center portion rising high above its drooping bow and stern.

Attempts were made to increase the rigidity of the framework and address the other problems, and two additional flights were made, but the flights did not impress the military representatives in attendance that Zeppelin’s project deserved public funds, and Count Zeppelin was out of money. Zeppelin was forced to dismantle LZ-1.

But while LZ-1 itself was not a success, Count von Zeppelin’s basic concept — of a long rigid metal frame containing individual gas cells and covered by fabric — was sound, and formed the basis for all future zeppelin airships.

Count Zeppelin’s second ship, LZ-2, was not built until five years later, with funds raised partly from a lottery approved as a favor by the King of Württemberg, and partly by the mortgage of Countess Zeppelin’s family estates.

LZ-2 made its only flight on January 17, 1906. Zeppelin had replaced the 14 hp engines used on LZ-1 with 80 hp Daimler engines, which gave LZ-2 sufficient speed to maneuver in light winds, but engine failure forced an emergency landing during the ship’s very first flight, and it was destroyed on the ground by a storm that evening.

Destruction of LZ-2.

While an improvement over LZ-1, Count Zeppelin’s second ship still did not incorporate basic design elements which would later be recognized as essential to flight stability and control, such as vertical and horizontal stabilizers and control surfaces. But LZ-2 did represent a significant technical advance due largely to engineer Ludwig Dürr; the weak tubular girders of LZ-1 were replaced by triangular girders (visible in photo above), which provided dramatically improved rigidity and strength. Triangular girders similar to those used on LZ-2 would be used on every subsequent zeppelin airship, and Ludwig Dürr would remain as chief engineer, designing every ship built by the Zeppelin Company after LZ-2.

LZ-2. The stronger, more rigid frame provided by Ludwig Dürr's triangular girders can be seen, but the ship still lacked fins for stability or control.

The next two ships, LZ-3 and LZ-4, were even greater advances in technology, with huge increases in controllability, power, speed, range, and payload. Large horizontal fins and elevators finally provided greater pitch control and stability, and the ships were capable of producing aerodynamic lift. Longer and more reliable flights became possible; in 1907, LZ-3 made a flight of 8 hours, and on July 1, 1908, LZ-4 made a flight of 12 hours over Switzerland.

LZ-3 in flight.

The record-breaking Switzerland flight of LZ-4 brought national attention to the success of Count Zeppelin and his machine, and the public began to look on the airship as a practical innovation. On July 3, 1908, King Wilhelm II of Württemberg and his wife, Queen Charlotte, were passengers on the fifth flight of LZ-4.

Tail of LZ-3, showing horizontal stabilizers which were lacking on LZ-1 and LZ-2.

The German government promised financial support for Count Zeppelin’s efforts if his ship could make an endurance flight of 24 hours, and confidant in his ship’s ability, Zeppelin agreed to the challenge. LZ-4 departed the Bodensee on August 4, 1908, for a 24-hour trial.

LZ-4 leaving its hangar on the Bodensee for the 24 hour test flight that ended at Echterdingen.

Just as it seemed that Count Zeppelin and his team had mastered the basics of airship design and operation, LZ-4 was forced to make an emergency landing in a field at the town of Echterdingen on August 5, 1908, during the 24-hour endurance flight. Pulled by a sudden storm from its temporary mooring, the ship crashed and was soon destroyed by a fiery explosion of hydrogen.

Wreckage of LZ-4 at Echterdingen.

In response to the crash, rather than lose faith in Count Zeppelin’s work, the German public rallied behind Zeppelin’s efforts; in what became known as the “Miracle at Echterdingen,” Germans contributed 6 million marks for the construction of a new airship and gave new life to the zeppelin enterprise.

Wreckage of LZ-4 at Echterdingen.

The fervent financial and political support of the German public and government following the crash at Echterdingen allowed the Count to establish the Luftschiffbau Zeppelin (Zeppelin Construction Company) in September, 1908. Alfred Colsman was the Zeppelin Company’s business manager, and in 1909, journalist Hugo Eckener joined as the company’s director of public relations; within 2 years, Eckener would be an airship commander.

Early zeppelin under construction at floating hangar on the Bodensee.

Colsman would shortly establish DELAG, the Deutsche Luftschiffahrts-Aktiengesellschaft (German Airship Transportation Corporation Ltd) as a affiliate of the Zeppelin Company, to commercialize zeppelin travel by providing passenger service.

Early zeppelin at floating hangar on Bodensee.

Friday, February 18, 2011

Thompson M1921 M1928 M1/M1A1 submachine gun

John T. Thompson founded the Auto Ordnance Corp. in 1916, and began his developments in submachine guns with purchase of John Blish patent (1915), that described a delayed blowback automatic firearm. This patent described delayed blowback breech system in which a sloping metal wedge interlocked the breech block with the gun body. Under high pressure, as when the cartridge fired, the angle of the slope was such that the mating faces jammed solid. As the pressure dropped, the faces were able to slip across each other, the wedge moved up due to the slope, and the breech unlocked. This idea was used in all Thompson submachine guns except for M1 and M1A1 (those were simply blowback operated).

 Thompson M1 submachine gun with 20-round magazine.

The first Thompson experimental submachine gun appeared in 1919, and first production model appeared in 1921; it was manufactured under contract by Colt Firearms Manufacturing Co, as well as later M1928 models. Production of M1928A1 and M1 submachine guns was carried out by Auto-Ordnance and Savage, and some licensed copies were manufactured by B.S.A. in Great Britain.

Thompson M1A1 submachine gun with 30-round magazine.

There also were some submachine guns that never reached full-scale production, such as "Military model" M1923, which was developed with intent to extend the effective range out to 600 yards (approx 550 meters). To achieve this goal, M1923 was chambered for a special .45 Remington-Thompson ammunition, which fired heavier 250-grain (16,2 gram) bullet (as opposed to standard 230-grain .45ACP bullet) at higher muzzle velocities of about 1450 fps (440m/s). This weapon also had longer barrel, and optional bipod and bayonet mount. It was tested but never produced in any significant numbers. The other rare version was the original Model 1927, which was a semi-automatic only version of Model 1921.

Thompson Model 1921 submachine gun with 20-round box ("stick")magazine.

The first Thompson gun to see some military use was Model 1928, used by US navy during its expedition in Nicaragua. The so-called "Navy" model 1928 was distinguished by a horizontal forearm that replaced the front grip, and by added sling swivels. With the start of World war 2, US Army procured a large number of Model 1928 submachine guns in "Navy" configuration, marked as US Model 1928A1. These weapons were rather expensive to make, and in 1942 Army adopted a simplified version of M1928A1, known as M1. A little later, an M1A1 version was adopted, which further simplified the design by adoption of a fixed firing pi; otherwise M1A1 were similar to M1 submachine guns. Thomson submachine guns served in US Army well into the Vietnam era, although in limited numbers. American police used Thompson guns until 1970s or 1980s, and few still could be found in some police armories in USA and several other countries of the world.

 Thompson experimental Model 1923 "Military model" submachine gun, for special .45 Remington-Thompson ammunition.

Thompson submachine guns were widely exported commercially prior to and after WW2; Many guns were supplied to Britain and USSR through Lend-lease program during WW2. It must be noted that Soviet troops generally not liked Tommy guns, because of excessive weight and lack of bullet penetration, compared to 7,62mm submachine guns such as PPSh-41 or PPS-43.

 Thompson Model 1928 submachine gun with 50-round drum magazine and Cutts compensator.

Thompson M1921 and M1928 submachine guns were delayed blowback operated, selective fired weapons, based on Blish principle. Blish patent described a delayed blowback breech system in which a sloping metal wedge interlocked the breech block with the gun body. Under high pressure, as when the cartridge fired, the angle of the slope was such that the mating faces jammed solid. As the pressure dropped, the faces were able to slip across each other, the wedge moved up due to the slope, and the breech unlocked. The wartime M1 and M1A1 submachine guns used simple blowback action. All Thompson submachine guns fired from open bolt. The cocking handle was located on the top of receiver on Models of 1921 and 1928, ad on the right side of the receiver on models M1 and M1A1. Separate manual safety and fire mode selector levers were located on the left side of receiver, above the trigger. Barrel was usually partially finned, and on model 1928, fitted with so-called Cutts compensator (not present on M1 and M1A1). Feed was from double-row box magazines containing 20 or 30 rounds, or drum magazines holding 50 or 100 rounds. Box magazines were inserted into the magazine slot from below; drum magazines were inserted into the same slot from the side. Drum magazines were not available for M1 and M1A1 submachine guns.

Side-by-side comparison between M1928A1 (left) and M1 (right) Thompson submachine guns.

Furniture included pistol grip, detachable wooden shoulder stock and either a detachable forward grip or a horizontal forearm. Sights on pre-war models included front blade and protected rear, which combined a fixed open-notch blade and raising diopter, which was adjustable for both windage and range (up to 500 yards). Wartime models (M1928A1, M1 and M1A1) used a simple fixed aperture (diopter) rear sight, with or without protecting side "ears".

 Thompson Model 1928A1 submachine gun with 20-round box magazine and Cutts compensator.

At the present time, Kahr Arms makes a variety of "Tommy-guns" under Auto Ordnance trade mark. These weapons are limited to semi-automatic fire only and usually have longer barrel to conform to US laws.

Thompson Model 1928A1 submachine gun, wartime production (simple, non-adjustable and non-protected rear sight and plain barrel).

Controls of M1928A1 submachine gun; M1 controls were in same positions but with levers of simplified shape.


  M1921 M1928 M1
Caliber .45ACP .45ACP .45ACP
Weight, empty 4.69 kg 4.9 kg 4.78 kg
Length 830 mm 852 mm 811 mm
Barrel length 267 mm 267 mm 267 mm
Rate of fire ~ 1000 rpm ~ 700 rpm ~ 700 rpm
Magazine capacity 20 or 30 rounds box
("stick") magazines and
50 or 100 rounds drums
same as M1921 20 or 30 rounds box
Effective range 100-150 meters 100-150 meters 100-150 meters

Wednesday, February 16, 2011

Calico M960 submachine gun

The Calico submachine guns are somewhat mysterious and quite notorious in both design, concept and appearance. The key properties of Calico firearms were extremely large magazine capacity combined with slim profile and ambidextrous handling. First designs, introduced by the US based company Calico Light Weapon Systems (LWS) circa 1990, were intended for both Law Enforcement and Military markets (in either semi-auto or selective fired form, in 9mm) and for civilian market (semi-auto only, in pistol or carbine form, in 9mm and .22LR versions). Sales of these guns were not so bright, and the US Assault Weapons Ban of 1994, which limited magazine capacity for civilian guns to 10 rounds, further impacted the future of this weapon. Apparently, military and police sales during late1990s were insufficient, and it seems that the Calico LWS company went out of business.

Calico M100 .22LR (5.6mm rimfire) pistol with 100 rounds magazine. Note ejection port on the right side, characteristic round handguards, front sight and flash hider.

Original design of the helical, large capacity magazine was invented by the Michael Miller and Warren Stockton by the 1985, and refined by the 1988. Calico company produced 2 basic designs, one in .22LR (models 100, 105 and 110), and another in 9mm Luger (models 900, 950, 960, Liberty). 9mm models could be easily distinguished by the ejection chute, located just ahead of the trigger guard, and opened to the bottom. .22LR models, on the other hand, have trigger guards with slim front edge, and ejection ports on the side of receivers.

Calico M950 9mm "pistol" with 50 rounds magazine.

The 9mm Calico submachine guns were delayed blowback operated, selective fire weapons. The action is based on the two part, roller delayed blowback boltsystem, initially designed by Ludwig Vorgrimler at the Mauser Werke by the end of WW2, and latter refined and promoted by the Heckler & Koch company in itsG3 series rifles and MP5 series submachine guns. One interesting feature of Calico submachine guns is that the spent cases are ejected straight down,through the ejection chute at the front of the trigger guard. This, along with the ambidextrous safety / selector switch, located at the front of the trigger guard, make the gun ambidextrous, but bottom ejection caused danger to the shooter in the case of improper two-hands grip - if the supporting hand will come too close to the trigger guard, ejected cases can cause burns and damage to the holding palm. The charging handle is located at the left side of the gun,just ahead and above the trigger, and does not move when gun is fired. It also must be pointed out, that the .22LR versions of the Calico guns had the ejection port at the right side of the receiver, above the pistol grip.

Calico 9mm semiautomatic "carbine" with 100 rounds magazine.

The most interesting feature of the Calico firearms is the top-mounted, cylindrical magazine of impressive capacity. Made mostly of plastics, this magazine contains a helical guide grooves at its "inner" cylindrical wall, with the rotating central "follower", that causes the cartridges to follow the helical track inside the cylinder. The follower is operated by the spiral spring, located at the rear of the cylinder. Magazine is equipped with winding handle, so it can be stored loaded and with unwound spring, to avoid loss of spring tension during the storage time. When required, magazine spring could be quickly wound up by rotating the handle to prepare magazine for fire. Magazines for Calico guns can store 50 or 100 rounds in relatively compact packages.

Calico M960 9mm submachine gun with 50 rounds magazine, collapsed butt and front grip.

Another interesting feature of all 9mm and some .22LR Calico guns is that while the adjustable front sight is mounted on the trapezoid block on the weapon itself,the rear sight is formed as the part of the plastic magazine shell. Calico firearms in submachine or carbine form could be fitted with retractable butt and/ or forward pistol grip. Calico "pistols" had no butts, but still had short forearms and were fitted with shorter barrels. .22LR semiautomatic versions also can be found in either pistol or carbine versions (latter with longer barrels, detachable or under-folding butts and ribbed forends of round cross-section). Many .22LR guns also were fitted with conical"blaster-like" flash hiders at the muzzle, which also carried the front sight base (rear sight was at the front of the magazine holding block).

Сut-out drawing of the Calico M950 pistol, showing its general layout and feed system.

Drawing from original patent, protecting the large-capacity magazine for 9mmCalico firearms (.22LR magazines were of slightly different design and thus were protected by another patent).

Caliber: 9x19mm Luger/Para
Weight: 2.17 kg empty
Length (stock closed/open): 647 / 835 mm
Barrel length: 330 mm
Rate of fire: 750 rounds per minute
Magazine capacity: 50 or 100 rounds


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