750 lb M117 cone 45 bomb

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This page is about the American M117 cone 45 (750 lb) bomb. For other versions, see M117 (Family).

Description

Side view of M117 with it's fins mounted 45° in relation to the mounting lugs.

The M117 is a 750-lb demolition bomb designed and built to have a higher blast effect than a standard general-purpose bomb of comparable weight.[1]

Ordnance crews bolted the conical-type fin assembly to the tapered aft-end of the bomb body before usage. The fin assembly mounting occurred in one of two ways: at 90 degrees (cone 90) or 45 degrees (cone 45) in relation to the mounting lugs. Having multiple mounting options allowed mounting the bombs in bomb bays or on pylons without the fins interfering or knocking into adjacent bombs.[1]

The United States began using the M117 in the 1950s during the Korean War and continued through the early 2000s. Several nations, including China, Germany, Israel, Sweden, and Japan, also utilized this bomb. The United States Air Force had issues with early bombs, specifically with the fuses designed to work with older general-purpose bombs from World War II. The faulty fuses led to multiple mishaps where a bomb would detonate within several feet of the aircraft after being jettisoned, destroying the entire aircraft and crew. After the correction of the fuse issue, airborne mishaps virtually stopped.[2]


Vehicles equipped with this weapon

Vehicles equipped with this weapon
Jet fighters 
F-1  T-2 Early · T-2 · F-1
F-4  F-4C Phantom II · F-4E Phantom II · F-4EJ Phantom II · F-4EJ ADTW · F-4EJ Kai Phantom II · ◄F-4F Early · ◄F-4F · F-4J Phantom II · F-4S Phantom II · Kurnass · Kurnass 2000
F-5  F-5A · ␗F-5A · F-5C · F-5E · ␗F-5E · ▄F-5E FCU · F-20A
F-16  F-16D Barak II
F-100  ␗F-100A · F-100D · ▄F-100D · ␗F-100F
F-104  F-104C · ◄F-104G · ␗F-104G · ▄F-104G · F-104S · F-104S.ASA · ▄F-104S TAF
Kfir  Kfir C.2 · Kfir C.7
Nesher  Nesher
Strike aircraft 
A-1H  A-1H
A-4  A-4E Early · A-4E · Ayit
A-5  A-5C
A-7  A-7D · A-7E · A-7K
F-105  F-105D
F-111  F-111A
SAAB 105  SAAB-105G
Jet bombers  S.O.4050 Vautour IIA · S.O.4050 Vautour IIB · S.O.4050 Vautour IIN

General info

Bomb characteristics
Mass 362.42 kg (799 lb)
Explosive mass 175.1 kg
Explosive type Tritonal
TNT equivalent 206.62 kg
HE max penetration 89 mm
Armour destruction radius 9 m
Fragment dispersion radius 134 m

Effective damage

The M117 is a demolition bomb designed to have a higher blast effect than comparable sized general purpose bombs. This allows aircraft to deal more damage per bomb than with conventional general purpose bombs.

Comparison with analogues

Give a comparative description of bombs that have firepower equal to this weapon.

Usage in battles

This bomb is very good at destroying bases and can be used against lightly-armoured targets in ground battles due to its large amount of explosive. However, it may not be so easy to destroy top-tier Russian MBTs because of their ERA.

Pros and cons

Pros:

  • More powerful blast than standard general purpose bombs

Cons:

  • Dumb bomb, once released, cannot be guided to target

History

Early in aviation history, applications for aircraft to serve in a military capacity surfaced, not only with the intent to scout a battlefield from an aerial vantage point but for the possibility to drop explosive bombs too. Due to the frail nature of the early wood-frame and cloth covered aircraft, lifting capacity resulted in the ability to only carry small bombs. Effectively these early bombers were hailed as aerial artillery fire which could reach targets hundreds of miles further than the most powerful land-based cannons of the time. Prior to the war, contests abounded where pilots would drop oranges or flour sacks upon predesignated targets to see who could hit closes to the centre.

Italian aviators were the first to use bombs in a warfare capacity in 1912 during their campaign of Tripoli. These first bombs were conversions of existing cannon ammunition and were effective only against personnel as they did not provide a strong enough provision to damage hardened equipment or structures. As lifting capacity of aircraft increased, so did the ability for them to carry more and larger explosives.

For the United States, bomb design did not become a priority until the middle of 1917 when a French official came to the U.S. with several samples of the Gros-Andreau bombs which the French were using in large quantities at that time. Immediately these bombs were accepted by the U.S. and used as a standard in developing the first three sizes to be implemented in the military. These three bombs were known as the early "Mark" series, 25 lb Mk.I demolition bomb, 50 lb Mk.I demolition bomb and the 100 lb Mk.I demolition bomb. By December 1917, only six months later, the military put forth requirements for the development of bombs larger than the existing 100 lb bomb. After two more months of development, production of demolition bombs up to 1,000 lb was started. Rejected 3-inch artillery rounds were the basis for early 25 lb bombs which were modified into a streamlined shape, very similar to the British Cooper bombs of the time. Larger bombs were manufactured and filled with explosive filler, all of which were placed into a streamlined body, of which a cylindrical shape was the most advantageous.

Early on, the Mark series of bombs proved to be largely unsatisfactory in a number of different areas. The bomb body itself was weak due to the sheet metal it was made from and the number of welds needed to join the pieces together. The stabilizing fins were made of flimsy metal which tended to distort during both the handling and flight of the bomb, adversely affecting accuracy. For the field technicians, inserting the fuse was a complicated process which required removing the stabilizing fin structure potentially damaging the fins. The fuses tended to have a high fail rate and due to their design, they would instantly arm after release from the aircraft posing a direct to the delivery aircraft. Later modifications would eliminate many of the negative factors to include adding a nose fuse, time delaying arming of the fuse, strengthening of the stabilizing fins and adding primer detonators to ensure proper explosive train sequences. Other changes including streamlining all bomb bodies and utilising 100% T.N.T. as an explosive filler resulted in the newer "Modified Mark" series of Army bombs.

Prior to World War II, the military determined that the Modified Mark series of bombs were obsolete requiring newer and up-to-date bombs to be developed. Both the U.S. Army and Navy began development of their own series of bombs, the Army with the "M" series and the Navy with their "Mk" series. Both similar, these bombs were designed with parallel sides, an ogival nose and a boat tail which is a box type-tail reinforced to prevent warping and aid with accurate drops. Due to the shortage of T.N.T., the Army filled their bombs with 50/50 Amatol with T.N.T. ends to seal in the Amatol and protect it from moisture. The Navy, on the other hand, continued to manufacture their bombs with 100% T.N.T.

With the approach of World War II, the U.S. Army (including the Army Air Corps) and the Navy standardized their series of bombs allowing for interchanging between services, consolidating manufacturing capabilities and allowing for modifications which enabled British service aircraft to mount these bombs too. Even after the standardization of bombs in 1941, the standardization process went through a few phases of further refinement, the first of which changed all high-explosive bombs to be termed general purpose (G.P.) or general purpose high-explosive (G.P.H.E). Later the designation of demolition bomb would come back for a few specific bombs.

When bombs are dropped, there is always a chance that something in the explosive train of the bomb will fail and it will not explode. Early AN style bombs were defusable in the event they did not explode on contact, meaning that any unexploded AN bomb could have the fuses and boosters removed without the bomb exploding, rendering it inert. To counter this and allow for the potential "dud" bomb to explode when tampered with, the AN G.P.H.E. series bombs with the modification "A1" annotated that these bombs now had special pins mounted in the bomb's baseplate which fused with the explosive filler making it impossible to remove the booster without causing the bomb to detonate. Other modifications later added would include minor changes to the bomb body or the type of explosive filling used. During this time a second option for bomb tails was added, the box-type tail was already the mainstay of the bombs, however, to create a more aerodynamic bomb a conical tail assembly was added. This stretched out low profile tail improved the aerodynamics of the carrying aircraft, allowing it to carry more ordnance.

Progressing towards the Korean and Vietnam wars, piston-driven aircraft were giving way to jet fighters, bombers and attackers, many of which carried their ordnance on external pylons hung under the wing or underbelly. The new Mk 80 series bombs (Mk 81, 82, 83 and 84) were developed to keep external hung ordnance from creating too much drag on the delivery aircraft. Initially, the Mk 81 250 lb bombs were considered ineffective for their size or required a large amount to be effective and were removed from the munitions inventory. All-weather fighters and attackers were now being outfitted with the Mk series bombs and a new problem developed when it came to low-altitude attacks (typically coming in under low cloud cover) where the aircraft would deploy its ordnance which would hit the ground and explode catching the delivery aircraft in either the explosive blast or the shock-wave from the blast.

Modifications were developed to slow down or retard the flight of bombs, allowing for the delivery aircraft to depart out of the blast zone before they hit and detonated. Several options became available which allowed these bombs to remain aerodynamic low-drag while en-route to the target, but when deployed converted to high-drag, slower falling bombs. One option was to attach four bladed plates to the rear of the bomb so that when the bomb deployed, these plates would pop out and create high-drag to slow the fall. Another option was to use a ballute which was basically an airbag which deployed from the rear of the bomb that acted like a drogue chute, effectively causing high-drag. Later during the fighting in Iraq, the US military brought back the 250 lb Mk 81 bombs due to their ability to be used when deploying against a specific target and to help minimize collateral damage.

Media

Excellent additions to the article would be video guides, screenshots from the game, and photos.

See also

External links

Paste links to sources and external resources, such as:

  • topic on the official game forum;
  • other literature.

References

Citations
  1. 1.0 1.1 NAVWEPS OP 2216 - Volume 1 (1960)
  2. Lowery, J. (2019, February 26)
Bibliography


High-explosive and general-purpose bombs
USA 
100 lb  AN-M30A1
250 lb  AN-M57 · LDGP Mk 81
300 lb  H.E. M31
500 lb  AN-M64A1 · LDGP Mk 82
600 lb  H.E. M32
750 lb  M117 cone 45
1,000 lb  AN-M65A1 · AN-M65A1 Fin M129 · LDGP Mk 83
2,000 lb  AN-M66A2 · LDGP Mk 84
3,000 lb  M118
4,000 lb  AN-M56
Germany 
50 kg  SC50JA
200 kg  Sprengbombe
250 kg  SC250JA
400 kg  Sprengbombe
450 kg  Sprengbombe 68/70
500 kg  SC500K
1,000 kg  SC1000L2
1,800 kg  SC1800B
2,500 kg  SC2500
USSR 
25 kg  AO-25M-1
50 kg  FAB-50sv
100 kg  FAB-100sv · FAB-100M-43 · OFAB-100
250 kg  FAB-250sv · FAB-250M-43 · FAB-250M-44 · FAB-250M-46 · FAB-250M-54 · FAB-250M-62 · OFAB-250sv · OFAB-250-270
500 kg  FAB-500sv · FAB-500M-43 · FAB-500M-44 · FAB-500M-46 · FAB-500M-54 · FAB-500M-62
1,000 kg  FAB-1000 · FAB-1000M-43 · FAB-1000M-44
1,500 kg  FAB-1500M-46
3,000 kg  FAB-3000M-46
5,000 kg  FAB-5000
Britain 
250 lb  G.P. Mk.IV · M.C. Mk.I
500 lb  G.P. Mk.IV · H.E. M.C. Mk.II · M.C. Mk.I
540 lb  Mk.M2
1,000 lb  G.P. Mk.I · M.C. Mk.I · L.D H.E. M.C. Mk.1 · H.E. M.C. Mk.13
4,000 lb  H.C. Mk.II · H.C. Mk.IV
8,000 lb  H.C. Mk.II
12,000 lb  H.C Mk.I
Japan 
Army 
50 kg  Type 94 GPHE
100 kg  Type 94 GPHE
250 kg  Type 92 GPHE
500 kg  Type 92 GPHE
Navy 
60 kg  Type 97 Number 6
250 kg  Type 98 Number 25 · Type Number 25 Model 2
500 kg  Type Number 50 Model 2
800 kg  Number 80 Mod. 1
China 
250 kg  Type 250-2 · 250-3
500 kg  500-3
Italy 
50 kg  GP 50
100 kg  GP 100T · SAP 100M
250 kg  GP 250
500 kg  GP 500
800 kg  GP 800
France 
50 kg  D.T. No.2 · G.A. MMN. 50 · Type 61C
75 kg  G2 Navale
100 kg  No.1
250 lb  SAMP Mk 81
150 kg  I2 Navale
200 kg  No.1
500 lb  SAMP Mk 82
250 kg  Matra 25E · SAMP Type 25
400 kg  SAMP Type 21
1,000 lb  SAMP Mk 83
500 kg  No.2
2,000 lb  SAMP Mk 84
Sweden 
50 kg  mb m/37AT · sb m/42 · sb m/47 · Model 1938
100 kg  Model 1938
120 kg  sb m/61 · m/71
250 kg  mb m/40 · mb m/50
500 kg  mb m/41 · mb m/56
600 kg  mb m/50
Israel 
100 kg  100/50 kg G.P.
250 kg  250/50 kg G.P.
360 kg  360/50 kg G.P.
500 kg  500/50 kg G.P.
See also  List of armour-piercing bombs · List of guided bombs · List of retarded bombs