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Wednesday, September 28, 2011

Small Size Supplies Stunning Stealth

Small Size Supplies Stunning Stealth

September 27, 2011: South Korean officials are alarmed after discovering that the navy has only been able to detect 30 percent of the North Korean subs they come across. Moreover, North Korea is using its submarines more frequently in training (for sneaking people into South Korea) exercises. North Korea has a fleet of over 80 mini-subs, plus about 24 older Russian type conventional boats (based on late-World War II German designs, as adapted for Russian service as the Whiskey and Romeo class). China helped North Korea set up its own submarine building operation, which included building some of the large Romeo class subs. North Korea got the idea for minisubs from Russia, which has had them for decades. North Korea has developed several mini-sub designs, most of them available to anyone with the cash to pay. The North Korean minisubs range in size from 76 to 300 tons displacement. Over a dozen of these small subs are equipped to fire torpedoes.

The use of a North Korea midget sub to sink a South Korean corvette in March, 2010, forced the United States, and South Korea, to seriously confront the problems involved in finding these small subs in coastal waters. This was a difficult task, because the target is small, silent (moving using battery power) and in a complex underwater landscape, that makes sonar less effective.

There are some potential solutions. After the Cold War ended in 1991, the U.S. recognized that these coastal operations would become more common. So, in the 1990s, the U.S. developed the Advanced Deployable System (ADS) for detecting non-nuclear submarines in coastal waters. The ADS is portable, and can quickly be flown to where it is needed. ADS is believed to be in South Korea. ADS basically adapts the popular Cold War SOSUS system (many powerful listening devices surrounding the major oceans, and analyzing the noises to locate submarines) developed by the United States.

ADS consists of battery powered passive (they just listen) sensors that are deployed by ship along the sea bottom in coastal waters. A fiber optic cable goes from the sensors (which look like a thick cable) back to shore, where a trailer containing computers and other electronics, and the ADS operators, runs the system. ADS has done well in tests, but it has only recently faced the North Korean mini-subs. There, it was discovered how little capability South Korea warships had to detect the North Korean submarines. Moreover, there is not enough ADS gear to cover all the coastal areas where North Korean subs operate. South Korea is hustling to improve its anti-submarine capabilities. But decades of neglect will take years to recover from.

Thursday, September 22, 2011

AMRAAM For Allies

AMRAAM For Allies

September 18, 2011: The U.S. has ordered 437 AMRAAM radar guided air-to-air missiles, to be produced in the next year. Most (234) are the latest version, the AIM-120D. The rest are the older, AIM-120C7, version. Most of these are for foreign customers. Since it entered service two decades ago, over 40 air forces have bought AMRAAM.

AMRAAM entered service in 1992, more than 30 years after the first radar guided air-to-air missile (the AIM-7 Sparrow). AMRAAM was meant to succeed where the AIM-7 didn't. Vietnam, in the 1960s, provided ample evidence that AIM-7 wasn't really ready for prime time. Too many things could go wrong. Several versions later, the AIM-7 got another combat test during the 1991 Gulf War. In combat, 88 AIM 7s were launched, with 28 percent scoring a hit. The AIM 9 Sidewinder did worse, with 97 fired and only 12.6 percent making contact. That said, most of these hits could not have been obtained with cannon, especially when the AIM 7 was used against a target that was trying to get away.

AMRAAM was designed to fix all the reliability and ease-of-use problems that cursed the AIM-7. But AMRAAM has only had a few opportunities to be used in combat, and over half of those launched have hit something. The 120D version entered service four years ago and has longer range and greater accuracy and resistance to countermeasures. So far, AMRAAMs have spent over 1.7 million hours hanging from the wings of jet fighters in flight. Some 2,400 AMRAAMs have been fired, mostly in training or testing operations. That's about a quarter of those produced.

AMRAAM weighs 172 kg (335 pounds), is 3.7 meters (12 feet) long and 178mm (7 inches) in diameter. AMRAAM has a max range of 70 kilometers. These missiles cost about a million dollars each. The missiles are complex mechanical, electronic and chemical systems, and each of them, on average, suffers a component failure every 1,500 hours.

Wednesday, September 7, 2011

French UAVs Over Libya

French UAVs Over Libya

September 4, 2011: France revealed that it had sent some of its Harfang ("Eagle") UAVs to operate over Libya. The first mission took place on August 24th. The Harfang is a variant of the Israeli Heron TP UAVs. Harfang was meant to serve as a Predator substitute, until a new design can be developed in France. Equipped with a powerful (1,200 horsepower) turbo prop engine, the 4.6 ton Heron TP can operate at 15.5 kilometers (45,000 feet) altitude. That is, above commercial air traffic, and all the air-traffic-control regulations that discourage, and often forbid, UAV use at the same altitude as commercial aircraft. The Heron TP has a one ton payload, enabling it to carry sensors that can give a detailed view of what's on the ground, even from that high up. The endurance of 36 hours makes the Heron TP a competitor for the U.S. MQ-9 Reaper, which is the same size as Heron. The big difference between the two is that Reaper is designed to be a combat aircraft, operating at a lower altitude, with less endurance, and able to carry a ton of smart bombs or missiles.

Three Harfangs were purchased two years ago, and sent to Afghanistan last year. Initially, Harfangs in Afghanistan only flew about one sortie a week per aircraft. There were technical problems, and much of the time, only one of the three was available for service. The Harfang usually flies missions of less than 24 hours.

Despite the technical problems with the Harfangs in Afghanistan, France ordered a fourth one. France has tried to buy Predators, but the waiting list is long, and French troops need UAV support now. European aircraft manufacturers have yet to come up with a world class UAV design (like the American Predator and Reaper, or the Israeli Heron, etc.)

Chinese AWACS Mutate and Proliferate

Chinese AWACS Mutate and Proliferate

September 1, 2011: China is apparently using its new KJ-200 AWACS in the navy, as well as with the air force. The KJ-200 entered service in the Chinese Air Force four years ago, and export versions sell for about $145 million each. China has had to develop its own phased array radar for it. In addition to the 54 ton propeller driven Y-8 (which is based on the Russian An-12 and U.S. C-130) AWACS, there are versions using the, 21 ton Y-7, and 157 ton Il-76 jet. But all these AWACS versions are apparently considered less reliable, and more expensive to maintain, than the twin engine, 79 ton, Boeing 737-800. Chinese airlines (some of them controlled by the Chinese Air Force) have been using the 737-800 since 1999 (a year after this model entered service).

Six years ago, the Chinese Air Force realized it was not happy with its first four IL-76 AWACS (A-50s from Russia, converted to use Chinese KJ-2000 radar systems). This led to a smaller system carried in the Chinese made Y-8 aircraft (as the KJ-200). Eventually, as an experiment, the Chinese began outfitting a Boeing 737-800 airliner as an AWACS aircraft. There was apparently never more than one of the 737 AWACS. Even though these work much better than other versions, the U.S. bans the militarization of civil aircraft in Chinese service. Rather than risk more American embargos, the Chinese have held off proceeding with the 737 version.

China has also equipped its 21 ton, twin engine, Y-7 transport with a phased array radar similar to that used on the larger KJ-200 AWACS. The Y-7 is a Chinese copy of the Russian An-24. The Y-7 AWACS would be similar to the U.S. 23 ton E-2 that operates off carriers. The Y-7 was thought to be a version that could operate off China's coming fleet of aircraft carriers. But the Y-7 is also cheaper, and better suited for equipping more air force units with AWACS capability.

The Y-8 turboprop transport based KJ-200 carries a flight crew of five and a mission (AWACS) crew of about a dozen. The aircraft can stay airborne for about seven hours per sortie. The KJ-200 radar has a range of about 300 kilometers, and the computer systems are supposed to be able to handle 5-10 fighters at a time, and keep track of several dozen enemy targets.