Since the mid-seventies, US Army engineers have used the M128 GEMMS remote mining system. This product had high performance, but was large, heavy and uncomfortable. To complement such a system, a more compact product for a similar purpose was developed - the M138 Flipper. Like its predecessor, it had to place mines of the FASCAM family on the ground.
Compact installation
The next stage of work on the development of mining systems for ammunition line FASCAM (Family of Scatterable Mines - "Family of scattered mines") started in the second half of the eighties. The existing M128 installation weighed several tons and needed a towing vehicle, although it could organize a 1000x60 m minefield in one pass. The Pentagon considered it necessary to create a new mining system suitable for installation on any military equipment.
This sample later received the index M138 and the name Flipper. The project proposed the manufacture of a light launcher of the type of a multi-barreled grenade launcher, compatible with the FASCAM mine launch cassettes. Due to its small size, the installation had to be mounted on army vehicles. To solve this problem, it was necessary to sacrifice the dimensions of the ammunition ready for use, the speed of operation and other characteristics.
Installation M138 received a metal support with a clamp for mounting on the carrier machine and mounting the launcher. It was proposed to put the clamp directly on the side of the body of the carrier vehicle. The dimensions and strength of the clamp were determined taking into account the recoil when firing. The support had a hinged base for the launcher and a firing control unit.
Actually the "Flipper" launcher is a multi-barrel system with a caliber of about 130 mm. In the working position, cassettes with mines are placed in the barrels of the device. The design of the launcher provides horizontal guidance of barrels within a sector with a width of 180 °. Shooting is carried out with a constant elevation angle, which gives the same mine throwing range. The aiming control is carried out manually: the abandonment of any drives allowed to reduce the weight.
Shooting is carried out using an electrical system and an operator panel. When installing the M138, all electrical devices are connected to the vehicle's electrical system. The console has several modes of operation. It can give impulses for firing only at the command of the operator, or fire in bursts with an interval of 10 seconds. With standard mining techniques, an interval firing mode is used.
The M138 Flipper system, both in combat and in transport position, has minimal dimensions. Its height does not exceed 1 m, its width is no more than 600-700 mm. Weight without ammunition - 110 pounds (50 kg). The fixed elevation angle allows you to send mines at a distance of 35 m. The rate of fire depends on the mode of operation.
Ammunition
The M138 remote mining system launches ammunition using special cassettes. Mines of different types, five in each, are packed into a metal cylindrical body. Between them, according to the type of so-called. Roman candle placed low-power propelling charges. The charges are ignited by an electrical impulse. The assembled cassette is a metal cup with a diameter of about 130 mm and a length of less than 450 mm with a sealed lid. On board the cassette there are contacts for the fire control system.
The Flipper product was intended for the installation of M74 anti-personnel mines and M75 anti-tank mines from the FASCAM family. Both mines had similar cylindrical hulls with a diameter of about 125 mm and a height of approx. 60 mm. The mass of the anti-personnel mine is 1.41 kg, including 410 g of the Composition B explosive. The M74 used eight nylon threads as target sensors. The mine provided destruction of targets within a radius of 4-6 m with the dispersion of fragments up to 25-30 m.
The anti-tank M75 weighed 1.7 kg and carried a 585-g shaped charge with funnels at both ends, due to which the armored object is hit regardless of the position of the mine on the ground. The detonation was carried out using a magnetic target sensor, which is triggered when a metal object approaches 1 m. Armor penetration is a few centimeters.
Both FASCAM mines for the M138 can be in place for 5-15 days with a pre-set time. After its expiration or when the batteries are discharged, the self-liquidator is triggered.
Work principles
Before going out for mining, the sappers had to prepare the M138 for work. With the help of a support with a clamp, the product is placed on the tailgate of almost any available car - HMMWV or truck. The choice of a carrier depends on the state of the engineering fleet. In the carrier's body, next to the launcher, a stock of cassettes with mines of the required types is kept. Operators were to work in the immediate vicinity of the facility.
Before mining, the marking of the future obstacle is carried out. Sections of 35 m are laid along the axis of the minefield and marks are made. Then the car with the "Flipper" should go to the first point; the crew places the cassettes in the launcher and starts firing. For mining to the required depth, sappers must fire cassettes one by one, turning the launcher at an angle of 15-20 degrees before each shot. Shooting begins with a maximum turn of the barrels in one direction and ends with a maximum angle in the other direction. Shooting several cassettes from one point allows you to lay mines in an arc or semicircle, the axis of symmetry of which is parallel to the front.
Further, the carrier vehicle passes another 35 m, reloading is performed and the second batch of mines is fired. According to this technique, an area of the required size is “seeded” with ammunition.
The firing range of an M74 or M75 mine is 35 m. Thus, by turning the M138 launcher to extreme positions, it is possible to organize an obstacle up to 70 m deep. As a result of several firing from different points, mines fall in curved lines and cover the entire front. The length of such a minefield depends on the consumption of cassettes / min and the duration of the sappers' work.
After installing mines in a given area, the calculation must disconnect the launcher from the systems of the carrier vehicle and remove it from the board. The compact foldable design allows the M138 to be transported by any available vehicle, including the carrier that performed the mining.
In service
The promising lightweight remote mining system M138 Flipper was put into service in 1991. Soon after, serial production began in the interests of the US Army. According to American regulations, an infantry division of a light type is entitled to three sets of "Flipper". One product is used in two sapper platoons, another one is assigned to the sapper company of the engineering battalion. The Airborne Division's Engineering Battalion operates one M138 product.
The M138 system was seen as an easy and convenient means of quickly setting up minefields in hazardous areas. Placing the installation on a car or armored vehicle allows sappers to quickly go to the mine-laying area and carry out mining. The installation of ammunition can be carried out both in advance and on the way of the enemy. However, the work at the front edge is difficult due to the low mining speed and the difficulties with ensuring the protection of the crew.
The M138 Flipper was originally designed to complement the heavier and less mobile trailed mining system M128 GEMMS. Subsequently, such an addition became a replacement. Due to not entirely satisfactory characteristics, the GEMMS product was withdrawn from service in the mid-nineties. Its tasks were distributed among other systems.
According to known data, the US Army is still operating a number of M138 products. Together with them, other remote mining systems are in service, incl. designed for the use of mines of the FASCAM line. The presence of several different means of mining, using standardized ammunition, provides flexibility in the use of explosive barriers and allows the use of weapons that best meet current requirements.
Together with the M138 systems, FASCAM mines install guns with special artillery shells, MOMPS modular devices, Vulcano self-propelled and aircraft installations, and Gator aircraft cassettes. How long the Flipper system will remain in service is unclear. She has limited characteristics, but gives the engineering departments the necessary capabilities and successfully solves her problems, which allows her to continue serving.
