GENERAL PURPOSE BOMBS.
General purpose (GP) bombs are designed to provide both blast and fragmentation effects. The most extensively used GP bombs are the 500, 750, and 1,000 pound munitions. For special missions, 2,000 lb GP and 3,000 lb demolition bombs may be available also. GP bombs of 500 and 750 pounds can be delivered in a low or high drag configuration.
Examples of effectiveness for various fuze options are shown below as crater widths and depths for several fuze/bomb combinations (earth detonated). In general, if blast and fragmentation effects are desired (personnel and materiel targets), proximity fuzes, fuze extenders, or instantaneous fuzing should be requested. If cratering or destruction is desired (roads, low bridges, or bunkers), appropriate short fuze delays should be requested. These crater dimensions apply only to the low drag configuration discussed in the subparagraph below; cratering efficiency will be significantly reduced for high drag bombs, because of less penetration.
Note that three figures for crater diameter and crater width are given for each type of ordnance and these correspond to soil types soft/medium/hard.
c. Low Drag Bombs.
(1) General. Low drag bombs (slicks) are cylindrical and are equipped with conical fins for external carriage on fighter aircraft. They have nose and tail fuzing to increase functioning reliability and to obtain the desired terminal effects (ie. blast, fragmentation or cratering.)
(2) Delivery. Low drag bombs will normally be delivered from a 20°- 60° dive angle. Level deliveries between 500' and 2000' AGL are possible for 750# and smaller bombs but optical sighting system limitations degrade the accuracy of such deliveries. Twenty degree dive deliveries require a ceiling of about 4000’ and a visibility of about three miles. However, deliveries can be made with a ceiling of 2000 feet. The following table provides estimates of combat delivery accuracies for low drag bombs.
Methods of measuring delivery accuracy are Range Error Probable (REP), Deflection Error Probable (DEP) and Circular Error Probable (CEP). REP is half the range distance between two points, equidistant from the target, that contains 50% of the impact points. BEP is half the lateral distance between two points, equidistant from the target, that contains 50% of the impact points. CEP is equal to the radius of a circle around the target which contains half the impact points.
(3) Fuzing. The terminal effects obtained from a high explosive bomb are determined by its fuzing. Low drag bombs can be fuzed for instantaneous or delayed detonations after impact. Low drag bombs are usually configured with both a nose and tail fuze and the pilot has the capability of selecting either one or both fuzes. Therefore, if a bomb has one fuze with an instantaneous element and the other with a delay element, the pilot can select either instantaneous or delay fuzing as desired.
Fuzes compatible with the bombs and other munitions listed here include impact, proximity, and airburst time fuzes. Where a munition is limited to use with only one of these specific fuze classifications, it will be so noted in the weapon data. Reliability, safety features, weapon effects, and delivery considerations vary with the type of fuze used; consequently, selection of the proper fuzing is as vital as selection of the bombs themselves.
d. High Drag Bombs.
(1) General. High drag bombs are MK 82 (500#) and M117 (750#) bombs with the conical tail fin removed and folding retarding fins installed. These fins open after the bomb is released to provide the aircraft safe separation from the blast and fragmentation effects of the bomb. This provides the fighter aircraft with the capability to deliver ordnance under low weather conditions. Also, because of reduced slant ranges at release, the high drag bomb can usually be more accurately delivered than the low drag bomb.
(2) Delivery. High drag bombs will normally be delivered from 10° - 20° dive angles with releases 500-1,000 feet, AGL. This will require a ceiling of 2,000-4,000 feet and a visibility of 2-3 miles. Aircraft are vulnerable to small arms and light AAA fire during the delivery of high drag bombs. Therefore, low drag bombs should be used wherever possible and high drag bombs used only when weather or other situations dictate. The following table provides an estimate of the combat delivery accuracy for high drag bombs.
(3) Fuzing. The high drag bombs are double fuzed, nose and tail. The nose fuze for a high drag bomb is the same as that of a low drag bomb and can provide the same delays. The tail fuze provides only an instantaneous detonation. If a delay is desired, the tail fuze will not be used.
Napalm or "fire bombs" are cylindrical, thin skinned aluminum tanks filled with various types of incedigel mixes. It is one of the most versatile tactical fighter weapons since pilots have considerable leeway in delivery accuracy and need only insure that ordnance impacts are short of the target by about one-half the effective pattern length. Even with a near miss, napalm can be highly destructive to personnel, and to equipment that is vulnerable to its effects. Fuzing consists of an impact fuze which ejects white phosphorus (WP) into the splash pattern. Napalm cannisters have fuze igniters installed in both nose and tail. Napalm is available as 500# and 750# munitions and can be delivered in the unfinned or finned configuration. The napalm flame pattern may be as large as 40x180 meters when delivered from low altitude at high speed. Best delivery is parallel to friendly troop positions.
a. Unfinned Napalm.
(1) General. Unfinned napalm bombs are unstable after release with random tumbling until impact. Impact ruptures the napalm can and spreads the napalm mix over an area forward of the impact point.
(2) Delivery. Unfinned napalm is usually delivered from low (0° - 20°) dive angles, low (50’ - 800' AGL) altitudes and high (up to 500 knots, depending on aircraft) speed. Delivery can be conducted under ceilings as low as 800’ – 1000’ AGL with visibilities of 2 to 4 miles (The lower visibility is for slower aircraft). A-1 aircraft may deliver unfinned napalm in dives up to 45°.
b. Finned Napalm.
(1) General. Finned napalm has predictable ballistics which allow accurate delivery from high dive angles and altitudes. As dive angle or release altitude increases, however, the pattern size decreases and effectiveness is reduced.
(2) Delivery. Finned napalm is better suited for penetration of jungle canopies than unfinned napalm when delivered from dive angles of 20° or greater.
c. Delivery Accuracy.
The following table provides an estimate of combat delivery accuracy for napalm:
d. Napalm Mixtures:
(1) Napalm. Napalm is a mixture of gasoline and M-4 thickener which tends to adhere to a target. Napalm burns for approximately 15 to 30 seconds at temperatures up to 1400° F and is effective against combustible or partially combustible targets and those targets which can be damaged by intense heat. This category of targets includes: parked aircraft, vehicles, ammunition and supply depots in the open, POL dumps, stationary armored vehicles and tanks, unhardened radar and communication facilities, exposed personnel, and warehouses of combustible construction.
(2) Napalm B. Napalm B, the newest incendigel mix, provides increased burning times and improved terminal effects. It is a mixture of polystyrene, benzene, and low octane gasoline. Napalm B is more viscous than other incedigel mixes which improves its adherence to target surfaces and reduces the "fire ball" effect. It burns for up to 10 minutes.
a. General. The 2.75" folding fin aerial rocket (FFAR) was originally designed for air-to-air use, but is now used as an air-to-ground antipersonnel and materiel munition. Several different warheads can be installed. The rockets can be carried in two different launchers. The LAU-59 is a reusable launcher that carries 7 rockets. The LAU-3 carries 19 rockets and is jettisoned after firing.
(1) MK 1 (HE). The high explosive head produces blast and fragmentation. Detonation of the MK 1 head ejects 750 fragments with an average velocity of 3780 feet per second. These fragments are capable of penetrating 1/8" of mild steel at a distance of 30 feet from the point of detonation. When firing against targets on soft ground, most of the rocket fragmentation will probably be absorbed since warhead fuzing will allow the head to penetrate the ground prior to detonation. Lethal radius for a single rocket against men standing is 20’ and for men prone is 12’.
(2) MK 5 (HEAT). The high-explosive antitank warhead, with its specially designed shaped charge, is capable of penetrating up to six inches of armor with an impact normal (90°) to the surface. The weapon will have a negligible effect unless a direct hit is obtained.
(3) M151 (HEAP). This high-explosive antipersonnel warhead has a "super-quick" fuze which causes detonation prior to penetration of the head into soil or sand. Lethal radius for a single rocket against men standing is 39 feet and for men prone is 26 feet.
(4) WDU-4A/A (Flechette). This antipersonnel warhead contains 2400 twenty grain flechettes which are expelled from the warhead at motor burn out. The flechettes resemble small darts and inflict casualties by virtue of their high energy level at impact. Foliage degrades the effectiveness of flechettes and they should not be used under jungle canopy. Flechettes have very limited capabilities against materiel or shielded personnel. The following table shows pattern sizes for various delivery parameters:
(5) M156WP. The warhead contains 2.0 lbs of white phosphorous (WP) and 2.0 ounces of B-4 high explosive. Upon detonation, the high explosive ruptures the warhead and dispenses the WP to generate a white cloud of smoke.
c. Delivery Accuracy. All fighter aircraft deliver rockets from a dive, with angles varying from 10° to 45°. The following table provides an estimate of combat delivery accuracies for rockets:
a. General. There is a large group of munitions designated as cluster bomb units (CBU) which consist of a dispenser (SUU-XX) matched with a bomblet (BLU-XX). The complete round is designated a CBU. For example, CBU-24B/B = SUU-30B/B + BLU-26/A. These munitions produce a wide variety of effects, to include antimateriel, antipersonnel, area denial, and chemical riot control. The dispenser has the capability to distribute its payload widely, thereby spreading the effectiveness of the munition over a large area instead of concentrating the destructive energy in one small area which can result in near misses or over-kills.
(1) CBU-24/49. The CBU-24/49 consists of a clam shell dispenser which opens into two hemispherical halves, allowing the bombs to fall free and disperse in a somewhat elliptical pattern. CBU-24/49's are normally delivered from a dive (25° - 45°; 5000' - 8000') at high speeds (up to 550k depending on aircraft) but may be delivered from level flight or dive toss. A CBU-24/49 pattern size is about 530x530 meters for a single dispenser but may be considerably larger if premature opening occurs. The pattern for a single dispenser normally has an area within the pattern itself that is not covered by bomblets. This is known as the "donut" effect and the size of the hole is dependent upon dispenser opening altitude. This munition is not intended for use near friendly forces.
(2) Rearward and Downward Dispensing CBU's. These CBU's comprise a major portion of our CBU inventory (i.e., CBU14, 25, 33, 42, 46). They are normally delivered from level flight at relatively low (50'-500') altitudes and high (up to 600 knots depending on aircraft) speeds because of dispenser and optical sighting system limitations, and because this mode of delivery produces the best dispersion patterns. A-1’s however, may deliver these CBU's from a dive. The resulting patterns are normally long and narrow. The length of the patterns will depend on the type of dispenser used, number of bomb button depressions during the attack, number of tubes released per depression and release airspeed. A normal CBU pattern is about 30x400 meters. Delivery can be conducted under 800’-1000’ ceilings and with visibilities of 2-4 miles. The delivery should be parallel to friendly formations, with positions well marked. Delivery of CBU-25's and CBU-46's should be with the friendly forces on the right side of the aircraft to compensate for the left drift of the bomblets. Caution must be exercised in the vicinity of friendly troops near the ends of the CBU pattern, since delayed releases may extend patterns beyond desired areas. Additionally, aircraft should never fly over friendly positions once they have initiated CBU passes because some bomblets may dribble from the dispensers. The following table provides an estimate of combat delivery accuracies for CBU munitions.
a. General. 20mm ammunition may consist of high explosive incendiary (HEI) or armor-Piercing incendiary (API). The HEI projectile causes damage by blast, fragmentation and incendiary effects. At short range, HEI is effective against targets, such as vehicles, which can be penetrated due to the high striking velocity, and then destroyed by internal functioning of the explosive round. Against light vehicles, HEI is about twice as effective as API. HEI fragmentation makes it very effective against personnel. The API projectile Is designed for use against armored targets, and functions with a combined penetration and incendiary effect. Against hard targets such as locomotives and armored vehicles, HEI blast is absorbed by the target surface and the deeper penetrating API round is preferred. API produces no lethal fragments and is not effective against personnel for other than a direct hit.
b. Delivery. The following table provides estimated delivery accuracies for 20mm.
7.62mm ammunition may consist of ball or tracer rounds. The ball round is intended for use against personnel or materiel targets.
WEAPONS MINIMUM SAFE DISTANCES.
Minimum safe distances from various. weapons should be provided to both the FAC directing the airstrike and the ground commander requesting an airstrike close to his forces. It is not intended here to present all the factors affecting weapons delivery accuracy; however, consideration of expected delivery accuracy, weapon lethal radius, and target identification error should provide a minimum safe distance for initial munition delivery. These distances can be reduced. but the ground commander must make that decision based upon his estimate of the immediate situation. The following table shows the minimum safe distances from unprotected troops for delivery of ordnance. The distances listed represent the range at which a fragment from the particular munition will not penetrate the skin of an individual standing in an open field. The figures are based on a probability of kill of zero (Pk=0). They do not take into account aiming errors, pattern length, or pattern dispersions. The distances are from the actual point of impact. For the BLU-3/B and the BLU-26/59/B, the figure represents the actual point of impact of a single bomblet from the CBU dispenser. The safe distance for rockets is measured from the actual point of impact for a single 2.75" FFAR. The table also shows the minimum safe distances from protected troops that various types of ordnance may be delivered. The distances offer reasonable casualty-free risk for troops in armored vehicles, bunkers, trenches, or fox holes who are shielded from the point of detonation. They are based on 150% expected delivery accuracy, 200% lethal radius, 60 meters target identification error for high angle delivery, and 30 meters for low angle delivery.
Minimum Safe Distances (Meters)