e2janes

TACAN is an acronym for TACtical Air Navigation. It is the military version of the VOR/DME systems used in Civil Aviation, with additional features which offer both increased accuracy as well as in-band beacon identification.

TACAN consists of beacon stations, which can operation from fixed locations on the ground as well as on board vehicles (ships, ground vehicles, or even aircraft) as well as the TACAN navigation units. Note that both the beacon and navigation units contain both transmitter and receivers.

TACAN provides slant range and bearing from the beacon to the user's navigation unit. In addition, the beacon will identify itself through coded pulse transmissions, allowing the user to determine their position relatively accurately through the use of a single TACAN station, assuming they have position information for the TACAN station they are attempting to utilize via charts or tables. For convenience and efficiency in peacetime, most TACAN stations in the U.S. and Europe are colocate with civilian VOR/DME stations - such installations are known as VORTAC stations in both civil and military aviation.

In addition to its use for navigation, TACAN is used for aerial rendezvous. This is the reason TACAN beacons can be mounted aboard vehicles; the most common use of TACAN in this manner is to support aerial refueling missions. Tanker aircraft mount a single TACAN beacon whose identification code is distributed to their 'client' aircraft before a mission; by tuning in the tanker's TACAN signal when they are ready to refuel, aircraft can 'home in' on the tanker as needed.

How it Works
TACAN beacons consist of a central emitter ("radiator") around which are placed ten unpowered parasite radiators; nine in a ring around the central, and one adjacent to it. This entire assembly is then rotated at 900 RPM. The result is that a receiver will 'hear' a signal which will vary according to a known 'pattern' determined by the shape of the emitters (which is standard and well-known) and the speed (which is standard). When the assembly is 'facing' Magnetic East, it emits a standard sequence of pulses, known as the 'North Reference Burst' or 'Main Reference Burst.' It transmits reference pulses every 40 degrees of rotation otherwise. Given that indicator, and the position on the reference signal waveform from the rotation that the nav unit is receiving when the MRB occurs, it should be able to determine what its bearing from the assembly is.

In addition to its direction-finding capabilities, the TACAN beacon listens for interrogative transmissions from navigation units. When it receives them, it responds with an 'addressed' pulse. The navigation unit is responsible for timing the return pulse to determine slant range to the beacon, assuming a propagation speed of approximately 12.359 microseconds per nautical mile for the signal in atmosphere and a fixed delay between receipt and transmit.

Finally, the beacon randomly transmits identification pulses. These can be coded for security purposes, and the whole process can (and does, in more modern units) incorporate IFF security transactions.

Sources:
http://www.radarpages.co.uk/mob/navaids/tacan/tacan1.htm
http://www.rockwellcollins.com/ecat/gs/TCN-550_Tacan_PrintFriendly.html

Used by United States Army and Marine Corps to destroy vehicles, artillery barrels, captured enemy weapon systems, fuel caches, and munitions, the AN-M14 TH3 is about the size of an aluminum soda can and weighs 2 lbs.

The main component of the grenade is 600 to 800 grams of thermate, a variation of thermite created by the addition of barium nitrate, which burns for 40 seconds at 2200°C, is capable of melting through 1/2 inch homogeneous plate steel and will also burn underwater. It does not require an outside source of oxygen as it produces its own.

The fuse of the AN-M14 is an M201A1 which is also used with the AN-M83HC white smoke grenade and the M18 colored smoke grenade. The M201A1 has a straight safety lever which rests flush against the body of the cylindrical shaped grenade. The time delay element is a powder train requiring 1.2 to 2 seconds to ignite the main charge. As the firing time for this system is extremely short and it does not explode like an M67 fragmentation grenade, the device is not intended to be thrown long distances to its target, but instead activated and dropped, or set in place before the cotter pin is pulled.

The body of the system is flat gray and the markings, AN-M14 INCEN TH, are violet, but the standard color code for an incendiary grenade is light red with black markings, making its intended purpose easily recognizable.

As thermate burns at such a high temperature, looking directly at an ignited incendiary grenade can cause severe damage to the retinas.

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http://en.wikipedia.org/wiki/Hand_grenade
http://www.fas.org/man/dod-101/sys/land/m14-th3.htm
US FM 3-320.30 Dec, 1988


Thanks to rootbeer277 for the info on barium nitrate!

M-4 Bison

Developed by Vladimir M. Myasishchev in 1952, in answer to the Soviet government's demand for a bomber capable of delivering a strike on United States territory, the M-4 Bison was the nation's first four engine turbojet to become operational and following its maiden flight in 1953, the M-4 was first displayed in a fly-over Moscow on the first day of May in 1954. It reached a speed of 947 km/h and a ceiling of 12,500 meters. Although the bomber had a range of only 8,500 km, which did not allow strikes at US territory, series production of the M-4 bomber began in 1955. In July of the same year, deployment of the first ten bombers, intended to carry thermonuclear warheads, started.

During its initial flights the Bison had been equipped with the AM-3A engines since the BD-5 that would theoretically give it the desired range was still in its experimental stage. Between 1955 and 1956, the M-4 was equipped with more powerful and low-consumption PD-3M and PD-3M-500A engines to increase the range, but still not enough. With the new engines in place tests were conducted on the M-4's weapon capabilities, equipping it with the Kh 20 air-to-surface rockets which were to be used to strike targets outside of the bomber's range. Due to the design of the landing gear, the Kh 20 could not be mounted to the underside of the fuselage and a proposition to emplace the rocket above the wing was quickly rejected due to interference with the engines.

Again wishing to increase the bomber's strike range, the Bison was equipped with the VD-7 which improved its flight characteristics and bumped the range up tp 11,850 km and a revolutionary in-air-refueling system was designed as well, giving the M-4 the ability to deliver a maximum payload deep into enemy territory and return to the Motherland. The first flight of this design, designated the M4-3M, took place in March 1956, and at the end of the year production started although it would not be deployed until 1958.

A number of 'Bison-A' bombers were equipped to serve as in-flight refuelling tankers, with a hose-reel unit mounted in the bomb bay. This same type of refueling device was later adopted by the United States, United Kingdom, France, Italy and China.

Another version of the Bison was designed to be a high-altitude bomber, using a test-bed aircraft powered by four D-15 turbojet engines each of 13,000 Kg thrust and designated 201-M. This was used in September 1959 to establish a number of payload-to-height records.

Basic M-4 bodies were used to ferry the Buran orbiting space shuttle and Energiya rocket vehicles to and from launch stations in the Soviet Union and were designated VM-T. The VM-T used the fuselage and wings of the M-4, but the standard tail surfaces were replaced by large twin fins to allow the extremely heavy payload to sit above the fuselage.

All in all, seven basic variations on Myasishchev's design were created and tanker/transport versions the Bison remained in service until 1994.

Specifications:

Length: 47.20 M

Height: 14.10 M

Wingspan: 50.48 M

Wing Area: 309 M²

Ceiling: 12,500 M

Fuel Capacity: 262,710 L

Weight Empty: 79,700 Kg

Maximum Take Off Weight: 165,900 Kg

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http://www.fas.org/nuke/guide/russia/bomber/m-4.htm
http://www.aeronautics.ru/archive/vvs/m4-01.htm

nodeshell rescue

Special Forces Unit Patch

Worn by Special Forces soldiers of the United States Army, and also members of their support companies around the world, the Special Forces unit patch is comprised of a dagger with three lightning bolts crossing the blade, set within an upwards pointing arrowhead. As all Special Forces units are designated Airborne, the unit patch is accompanied by an arch-shaped Airborne tab, regardless of whether or not the soldier has been through Airborne School. For soldiers who have completed Special Forces training, the arrowhead patch and Airborne tab are placed below a longer tab embroidered with the words Special Forces.

On all Class A, or dress uniforms, of soldiers belonging to Special Forces units the patch is teal in color, representing the Special Forces' encompassing of all branch assignments. The dagger and lightning bolts are gold, representing constancy and inspiration. On a woodland camo BDU, or Battle Dress Uniform, the patch is olive drab and the dagger and lightning bolts are black to match the primarily green color of the garment. On a desert camo BDU the tab is light tan and the dagger and lightning bolts are dark brown.

The three combined designs that make up the patch all have historical origins and symbolic meaning, and as is custom with most Army units, Special Forces soldiers are expected to understand what their unit patch signifies.

Arrowhead: The arrowhead makes up the body of the patch and is symbolic of the craft and stealth of the American Indian, from which the basic principles and techniques of unconventional warfare were adopted during the Indian Wars of the 18th and 19th centuries.

Dagger: Set in the center of the patch, the dagger, a silent and deadly weapon, when pointing upwards is symbolic of unconventional warfare, fought up close on the enemy's territory. The blade itself represents the character of a Special Forces soldier, straight and true.

Lightning bolts: The three lightning bolts that strike diagonally across the blade of the dagger, from left to right, symbolize blinding speed, strength and stealth as well as the three methods of infiltration, by land, sea, and air.

As with all units of the Army, the Special Forces unit patch and Airborne tab is worn on the left shoulder of a soldier's uniform and if the soldier has seen combat with a Special Forces unit, the soldier is authorized to wear the patch and Airborne tab on his right shoulder (the Special Forces tab is only worn on the left side).

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http://members.cox.net/ric1551/insignia.htm
CSM M, SOCOM
MSG L, HHD 1/19th SFG(A)

The BLU-114 (and the updated version, the BLU-114/B) falls under the category of non-lethal bombs, and are also known as "Graphite bombs". Its old designation is CBU-94, and was known as the "Blackout bomb". It is developed for - and used by - the US Air Force.

The bombs are basically a lot of steel wool packed into plastic cover and a small parachute, which is precision-dropped above electrical transfer-stations and high-power lines. When above the target, a small explosive charge makes the canister come apart, and disperses the strands of carbon-fibre wires. The wires are so fine that they "float" downwards in a web-shaped pattern, to maximise the chance of hitting the target.

The purpose of the bomb is to shut down electrical installations by short-circuiting them: When used in Serbia in May 1999, a set of BLU-114 bombs took out 70% of the country's power grid.

Sources:
http://cryptome.org/blu114-yu.htm (also has pictures and a graph)
http://www.fas.org/man/dod-101/sys/dumb/blu-114.htm
Guinness book of World records 2000 ("Most destructive non-lethal weapon")