Hwasong-15 - TEL Tires
A few days after the first flight test of the Hwasong-15 full-range ICBM, Supreme Leader Kim Jong-un took time to drop by the Amnokgang Tire Factory that made tires for the country’s missile-launching vehicles. Kim shook hands with each official and thanked them for their trouble, saying that the working class of the factory solved the issue desired by the Party and gave great courage to him by making collective innovations in a drive for building new tires, and that he came to thank them.
The point of this exercise was to emphasize the fact that these tires were "off-road tires", of the sort used by all terrain vehicles. The visit emphasized the DPRK's claim that the movements of the Hwasong-15 are not confined to roads, but can range across the countryside, complicating the challenge to ROK/USA attack planning.
The photographs of the 29 November 2017 flight made it clear, however, that this first launch was conducted from a pre-prepared on-road site. If the Hwasong-15 could only be launched from such unique and readily identifiable sites, it would vastly simplify the task of destroying them on the ground before they could be launched.
A pre-emptive first strike by the USA could take out the fixed launch sites at Sohae and Tonghae, but North Korea is also believed to have road-mobile launchers that could survive to retaliate. The Hwasong-15 is among the North Korean missiles that can change location throughout the planning and execution phases of a war. These strategic relocatable targets pose a new threat because of the uncertainty about their location. To combat this new threat, new procedures must be developed to improve the chance of finding and destroying an SRT.
Land-mobile strategic missiles pose substantial intelligence challenges. Mobile missiles are more difficult to defeat than fixed-site missiles because they could be moved around secretly by the North Korean regime to make it more difficult for the U.S. to locate and target preemptively during a crisis. The relocatable target set impedes US ability to find, fix and finish the threat, a problem which is compounded by the fact that the US military did not have “persistent” intelligence, surveillance and reconnaissance assets over North Korea.
North Korea has a land area of 120,408 km˛, including irrigated land of about 14,600 km˛. Terrain on the Korean peninsula pose a significant issue to military commanders. Mountains and hills account for nearly 80% of land in the DPRK and lie on the north and eastern sides of the country. The southern and western most portions of the DPRK represent most of the arable land, predominantly rice paddies and dense urban terrain (DUT) litter that region.
DPRK forces use aspects of terrain and weather to their advantage. Training focuses on utilizing elements that are typically considered impassable or otherwise not factored into planning purposes of conventional Army forces. The utilization of poor terrain and inclement weather (to include monopolizing on the rainy season and/or typhoons, severely restricted terrain and ridgelines) is routinely practiced and trained at the tactical level, and is written into DPRK doctrine.
The NATO Reference Mobility Model is a prediction of maximum vehicle mobility performance. The output of GIS & NRMM software can produce a “Mobility Map” – a standardized land area in which terrain surface composition, surface geometry and vegetation are defined. GIS & NRMM will show GO & NO-GO segments for the specific vehicle over this terrain.
A mobile missile is launched from a transporter-erector-launcher vehicle. Mobile systems need bases from which to operate, and from which they would disperse in a time of crisis to avoid destruction by a preemptive attack. A rail-mobile system [which North Korea is not believed to possess, but India has built rail-mobile launchers for its Agni] would disperse along railroad tracks, while a road-mobile system would follow roads. An offroad—mobile system might initially move along roads, but could then move cross-country across suitable terrain that was sufficiently flat and free of obstructions such as trees. Obviously, rail-mobile systems would be easiest for an adversary to track, while road mobile systems would be much harder to track, as there are more roads than railroads. An offroad-mobiel system would be the most difficult to track, as the terrain with suitable trafficability might cover a significant fraction of the entire country.
Weapon system cycle time is the total time required from detection of a change in target location to weapon system arrival. Time critical targets have a dwell time less than the weapon system cycle time. Time constrained targets have a dwell time (time remaining in one spot) greater than the weapon system cycle time.
In trying to predict where the SRT will move, several questions come to mind. How fast does the target travel from one location to another? How far does the target travel before another stop is made? Once a new location is found, how long does the target stay in the same location before another move is made?
Terrain around the SRT can affect the speed of the target as well as limit the number of possible relocation sites. Terrain features such as dense forest or mountainous terrain can make relocation efforts very difficult. Average speed and distance traveled each move in this type of terrain can be considerably lower than for terrain that allows good mobility. Some segments of the movement area can be discarded from consideration. A smaller movement area means a smaller search area. An exhaustive search may prove infeasible because required search time is too long.
Kim Jong Un visited the factory that made tires for the country’s missile-launching vehicles and called for it to raise production, the Korean Central News Agency (KCNA) reported on 03 December 2017. The North’s state-run television KRT showed still photographs of Kim looking around the factory and said Kim ordered to make a large size tire for the 9-axis self-propelled launching vehicle of its own style for a ‘great event in November’. KRT didn’t elaborate the event but earlier this week the state media said a new Intercontinental Ballistic Missile (ICBM) was launched from a newly developed vehicle. Supreme Leader Kim Jong Un gave field guidance to the Amnokgang Tire Factory which successfully carried out the task for producing tires prioritized by the Workers’ Party of Korea (WPK).
He shook hands with each official and thanked them for their trouble, saying that the working class of the factory solved the issue desired by the Party and gave great courage to him by making collective innovations in a drive for building new tires, and that he came to thank them. He looked round the room for the education in the revolutionary history.
He underscored the need for the officials and workers of the factory to bear in mind the pride and honor of living and working at the glorious factory which was associated with warm love of President Kim Il Sung and leader Kim Jong Il and to bring about fresh miracles and innovations in production, so as to add eternal luster to the undying leadership exploits performed by the great leaders for making the industry of tire Juche-based. He went round all kinds of tires made at the factory and the newly developed large-size tires ready for the ballistic rocket self-propelled launching vehicle.
Accompanying him were Choe Ryong Hae, member of the Presidium of the Political Bureau of the Central Committee of the Workers’ Party of Korea, vice-chairman of the State Affairs Commission of the DPRK and vice-chairman of the C.C., WPK, and Hong Yong Chil, Jo Yong Won and Yu Jin, leading officials of the C.C., WPK.
Pneumatic tires designed primarily for offroad vehicles are well known and normally incorporate a tread designed to provide high traction in soft ground such as normally encountered by farm tractors, graders and other heavy equipment. The tread designs which have been preferred for OTR tires provide high traction in soft ground and expulsion of the earth from the transverse recesses between the deep lugs of the tread. Over the years many different lugged tires have been employed which meet these requirements.
Conventional OTR tires with deep widely spaced lugs cause severe pounding and vibration in contact with a hard highway surface. At higher speeds the vibration caused by conventional OTR tires can become intolerable. When using widely spaced lugs, large radial forces are transferred to the wheel axle because of concentration of tire load at the tip of each lug as it moves into contact with the road. It is difficult to provide a tire suitable for highway use which meets the requirements of effective OTR use, particularly the requirements as to traction and earth removal.
These tires have a very open tread pattern that employs elongated members called "lugs" which provide effective straight-line or "drawbar" traction to enable the vehicle to climb hilly and rough terrain. The tire employs a repeating pattern of long, intermediate length and short lugs arranged to provide improved traction. The arrangement of these lugs is such that each lug wraps completely over the tread shoulder region. The lugs are also circumferentially relatively closely spaced such that numerous lugs are in the footprint of the tire at any one time. The tire made according to this prior art invention is considered one of the best mud tires in its class according to its manufacturer.
Such tread designs conventionally employ a system of elongated lugs emanating from each lateral edge of the tread and extending to a position near the vertical centerplane of the tire, with the lugs emanating from opposite sides of the tire cooperating to form a generally herringbone pattern. To provide the necessary traction for operating heavy equipment and pulling heavy loads, the lugs are relatively deep and designed to bite into the ground surface. The generally herringbone arrangement of the lugs tends to expel the earth laterally of the tire to facilitate the biting action and prevent the lugs from filling with earth and losing traction.
It is well known in the tire designing technology that design features aimed primarily at providing the high draw-bar traction characteristics needed with a tractor tire is operated in a field may result in less than desirable ride comfort characteristics when the same tractor tire is operated on a hard surface roadway, and vice versa.
The space between circumferentially adjacent lugs of an off-road tire is commonly referred to as a "soil discharge channel." The soil discharge channels extend generally from the equatorial plane of the tread axially outwardly over the edge of the tread, called the "tread shoulder." The channels are designed to shed mud which accumulates in the channels, aided by gravity and centrifugal force generated by the rotating tire. In wet soils with heavy clay content there is a tendency for the tread of an off-road tire to pack with mud between the elongated lugs. If the soil discharge channels are packed with mud, the tread effectively loses its ability to provide any traction. This is because the lugs are buried in the packed mud, giving the tire the appearance of a slick or racing tread devoid of grooves.
The term "off-road" tires means pneumatic tires that have a primary use or working surface condition that is not on a paved road. Such tires include construction equipment tires, agricultural tires, lawn and garden tires, and all-terrain vehicle tires, including, but not limited to off-road dirt bike tires and ATV tires. Of particular interest are tires that have low operating pressures and minimal belt reinforcements. For example, ATV tires generally operate at less than 10 pounds per square inch ("psi") of pressure and often have no belt reinforcing structure. Unlike farm tires which travel at speeds of less than 25 miles per hour, ATV tires must be capable of speeds close to 50 mph. At such speeds the lugs must work in concert to prevent harsh vibrations from being created which could cause ride problems.
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