FIRING ON THE GROUND TARGETS USING AIR UNGUIDED MISSILES Miroslav JANOŠEK Abstract: In this article I will discuss air supporting ground forces in combat activity. The main topic is firing with air-to-ground unguided missiles with attached calculations of effectiveness of firing on the ground targets. Possible assaults for air unguided missiles are shown and calculated at the end of the article. Keyword: Firing, Targets, Air Unguided Missiles 1. Introduction Important part of air combat activity is supporting ground forces. In this context we have to consider problematics of effectiveness of air-to-ground unguided missiles. The effectiveness of firing is mostly affected by technical parameters of the used missiles, for example their caliber, dispersion of individual missiles and their number, etc., though we have to consider also the human factor. Other important factor is distance of the target related to dispersion of fire. Because of different behavior of the missile in variable conditions, such as distance of the target, wind, pressure, etc., we have to compare the missiles under the same conditions. 2. Analysis of possible Assault of the Air Forces when firing at Ground Targets Fighters, fighter-bombers and battle-planes carry immobile rocket blocks, which cannot change their direction during the flight. Because of rocket being unguided, the pilot has to aim his aircraft directly on the target; also we cannot forget that missile is affected by movement of the aircraft. If we want to analyze fire conditions of the aircraft, its required to consider maneuver capabilities as well. Fig. 1 Course of aircraft at assault of land target 33
Porobability of Destroying Figure 1 shows the movement of aircraft during air-to-surface assault. Aircraft is guided into the area marked as point B, wherein initiated aiming at a ground target. In between points F and E performs fire on ground target usually with one rocket salvo. At point E aircraft crew begins to level the aircraft. Crew has to finish leveling of aircraft in minimal safe height above the ground and don t get into the area where the fragments from explosion can cause damage on aircraft. There are some differences between air-to-surface and air-to-air firing. There are a lot of types of land targets, which differs mainly in their vulnerability. Air targets are generally more vulnerable, but there are a lot of types of land targets with different levels of vulnerability. Equipment used on land targets is much more effective in the results of fire calculation than the calculations of the aircraft maneuvers. Air targets are much easier to detect, than the land targets, which can be hidden or camouflaged. For approaching land target is typical high velocity of the aircraft, therefore the pilot has a short period of time for executing targeting maneuver and firing. A pilot has to be aware also of wind effect, which can heavily affect missile trajectory. From the tactical aspect, is important to mention the necessity to reach the minimum altitude for assault and to determine the minimum distance for beginning of targeting. Beginning dive of flight is determined both parameters. 1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 n=38 n=18 n=10 n=6 10 15 20 25 30 35 40 45 50 Dive Angle Fig. 2 Probability of destroying ground target using various number of unguided missiles As to learn the probability of destroying a land target for different dive angles, there are effectiveness characteristics for different numbers of air unguided missiles used at the velocity of the dive flight beginning Sa = 750 kph. Figure 2 shows the dependence probability of destroying ground target using various numbers of unguided missiles numbers 6, 10, 18 and 38. To assess the battle characteristics of the aircraft, it is probability of destroying on the dive angle. 34
Figure 3 shows the dependence of the distance of beginning of targeting on the dive angle when, considering the velocity Sa = 750 kph and the dive angle λ = 30, the distance of the beginning of targeting is D = 1 250 m, but at Sa = 400 kph, the distance is also reduced to the value of D = 670 m. Distance [m] 3000 2500 Sa = 900 kph 2000 Sa = 750 kph 1500 Sa = 550 kph 1000 Sa = 400 kph 500 0 5 10 15 20 25 30 35 40 45 50 55 Angle of Dive [ ] Fig. 3 Dependence of the distance of the beginnig of aiming on the dive angle From the fig. 3 results that the low speed is very advantageous, especially concerning the necessity to climb higher altitude and to begin the assault in a shorter distance from the target, considering possible fire of the antiaircraft equipment of the enemy. 3. Calculations of the possible Aircraft Assaults Area of the assaults useful of airplane to determine "area of possible assaults" for a particular land target. It is an area around the target in which the aircraft can deliver effective aimed fire. Figure 4 shows a particular area of possible assaults for the L159 aircraft at the velocity of the dive flight beginning Sa = 400 kph and at the multiple of the G-force of the aircraft when leaving the assault n = 4. In this case the altitude of the cloud base is 1 000 m which reduces the maximum dive angle in assault to the value of λ = 43. The distance to finish the fire is limited by safe leaving altitude and by the range of the air unguided missiles fragments. The resulted area of possible assaults of the aircraft and the calculations of the probability of destroying a particular target serve as an important basis for the aircraft crews as well as for the air control posts to set the actual way of assault near the target and the number of aircraft necessary for accomplishing the mission. When using the air unguided missiles, the maximum effectiveness in destroying targets is conditioned by the minimum fire distance. Consequently, from the point of view of the fire distance, the "area of possible assaults" is moved to the nearest possible distance away from the target, i.e. the internal limit of the area of possible assaults is determined by the cease fire distance. This distance, according to the calculations as 35
well as practical experience in launching air unguided missiles, ranges from 200 to 500 m and it affects, together with the aircraft velocity, to a great extent the fire effectiveness. It is well-known that the open and cease fire distances, but also the distance of beginning of targeting work as functions of the dive angle. Fig. 4 Area of possible assaults for aircraft using unguided missiles That implies the requirement for accurate choice of applicable range of dive angles. This range results, first of all, from the type of the aircraft, but its choice is determined by other circumstances such as the aircraft armament characteristics, target characteristics, i.e. its vulnerability, its dimensions, its location in the terrain and last but not least, the anti-aircraft defence of the target. The chosen range of dive angle is not always feasible. The feasibility of this range depends also on the altitude of the cloud base and on the maximum targeting distance which results from the target identification and from the used aiming device characteristics. 4. Conclusions It is possible to conclude with the statement that the fire effectiveness depends, except to the tactical and technical characteristics of the air unguided missiles, on the target characteristics, on enemy's aircraft defence, on the level of the crew technical and psychological training, and on the particular conditions under which the missiles will be used. Further, the calculations proved a considerable effect of the aircraft velocity in dive flight on the related distance and the dispersion of fire. The disadvantage of using the air unguided missiles in dive flight is the necessity to climb certain altitude before beginning the assault. This fact makes it difficult or even impossible to use this type of action under low cloudiness, but the main point is that the aircraft is exposed to the fire of the enemy's anti-aircraft defence for quite a long time. 36
References [1] JANOŠEK, M. Possibilities of using guided military equipment on the aircraft L- 159. International 7 th Symposium on Weapon Systems: University of Defence Brno, May 4 th 6 th, 2005, Czech Republic. ISBN 80-7231-007-0. [2] JANOŠEK, M. Effectiveness of the Air Unguided Missiles When Firing at Land Targets. In: International Conference ICATE, Romania, October 17 th -19 th, 2002. 37