The
Mk 4 Folding-Fin Aerial Rocket (
FFAR), sometimes called the
Mighty Mouse, was a 2.75 in (70 mm) diameter unguided
rocketA rocket is a self propelled, unguided weapon system powered by a rocket motor.- Categorisation :In military parlance, powered munitions are broadly categorised as follows:* A powered, unguided munition is known as a rocket....
weapon commonly used by
U.S.The United States of America is a federal constitutional republic comprising fifty states and a federal district...
military aircraftA military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:...
. It was intended as an
air-to-air weaponAn air-to-air rocket or air interception rocket is an unguided projectile fired from aircraft to engage other flying targets. They were used briefly in World War I to engage enemy observation balloons and in and after World War II to engage enemy bombers...
to allow
interceptor aircraftAn interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
to shoot down enemy
bomberA bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on them, or – in recent years – by launching cruise missiles at them.-Classifications of bombers:...
s with greater range and effectiveness than
machine gunA machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
s or
cannonA cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
. It was later developed into a modular rocket motor for air-to-ground use.
History
The advent of
jet engineA jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s for both fighters and bombers posed new problems for interceptors. With closing speeds of 1,500 ft/s (457 m/s) or more for a head-on interception, the amount of time available for a fighter pilot to successfully target an enemy aircraft and inflict sufficient damage to bring it down was vanishingly small.
WartimeWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
experience had shown that .50 caliber (12.7 mm) machine guns were not powerful enough to reliably down a bomber, certainly not in a single volley, and heavy
cannonA cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
did not have the range or rate of fire to ensure a hit. Unguided rocket weapons had been proven effective in ground-attack work during the war, and the
LuftwaffeLuftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
had shown that volleys of their
Werfer-Granate 21 rockets, first used by elements of the
Luftwaffe's JG 1 and JG 11 fighter wings on July 29, 1943 against USAAF bombers attacking
KielKiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
and
WarnemündeWarnemünde is a sea resort and northmost district of Rostock in Mecklenburg-Vorpommern, situated on the Baltic Sea in the northeast of Germany at the estuary of the river Warnow.- History :...
, could be a potent air-to-air weapon as well. The introduction in the summer and autumn of 1944 saw the adoption of the folding-fin R4M unguided rocket for use, underneath the wings of the
Messerschmitt Me 262The Messerschmitt Me 262 Schwalbe was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems prevented the aircraft from attaining operational status with the Luftwaffe until mid-1944...
jet fighter for
bomber destroyerHistorically, several aircraft were designated bomber destroyers prior and during the Second World War. They were interceptor aircraft dedicated to destroy enemy bomber aircraft with exceptionally powerful armament...
duties against the USAAF's Eith Air Force heavy bombers.
The FFAR was developed in the late 1940s by the US Navy
Naval Ordnance Test Center- About : is part of under Commander, Navy Installation Command and is located in the Western Mojave Desert region of California, approximately north of Los Angeles. Occupying three counties – Kern, San Bernardino and Inyo – the installation’s closest neighbors are the cities of Ridgecrest,...
and
North American AviationNorth American Aviation was a major US aerospace manufacturer, responsible for a number of historic aircraft, including the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F-86 Sabre jet fighter, the X-15 rocket plane, and the XB-70, as well as Apollo Command and Service...
.
The original Mk 4 FFAR was about 4 ft (1.2 m) long and weighed 18.5 lb (8.4 kg), with a high-explosive
warheadThe term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
of about 6 lb (2.7 kg). Like the Third Reich
Luftwaffe's R4M projectile of World War II, it had folding fins that flipped out on launch to spin-stabilize the rocket, with the FFAR using half the number (four) of fins in comparison to the R4M's set of eight folding fins. Its maximum effective range was about 3,700 yards (3,400 m). Because of its low intrinsic accuracy, it was generally fired in large volleys, some aircraft carrying as many as 104 rockets.
FFARs were the primary armament of many
NATO interceptor aircraftAn interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
in the early 1950s, including the
F-86DThe North American F-86 Sabre was a transonic jet fighter aircraft. Produced by North American Aviation, the Sabre is best known as America's first swept wing fighter which could counter the similarly-winged Soviet MiG-15 in high speed dogfights over the skies of the Korean War...
,
F-89The Northrop F-89 Scorpion was an early American jet-powered fighter designed from the outset as an all-weather interceptor. Though its straight wings limited its performance, it was among the first USAF jet fighters with guided missiles, and notably the first combat aircraft armed with air-to-air...
,
F-94CThe Lockheed F-94 Starfire was the United States Air Force's first operational jet-powered all-weather interceptor aircraft. It was a development by Lockheed of the twin-seat T-33 Shooting Star trainer aircraft.-Design and development:...
, and the CF-100. They were also carried by the
F-102 Delta DaggerThe Convair F-102 Delta Dagger was a US interceptor aircraft built as part of the backbone of the United States Air Force's air defenses in the late 1950s. Entering service in 1956, its main purpose was to intercept invading Soviet bomber fleets...
to supplement its guided missile armament.
The Mk 4 was dubbed "
Mighty MouseMighty Mouse is an animated superhero mouse character created by the Terrytoons studio for 20th Century Fox.-History:The character was created by story man Izzy Klein as a super-powered housefly named Superfly. Studio head Paul Terry changed the character into a cartoon mouse instead...
" in service, after the popular cartoon character.
The Mighty Mouse was to prove a poor aerial weapon. Although it was powerful enough to destroy a bomber with a single hit, its accuracy was abysmal. Its spin rate was not high enough to compensate for the effects of wind and gravity drop, and the rockets dispersed widely on launch: a volley of 24 rockets would cover an area the size of a football field.
As a result, by the late 1950s it had been largely abandoned as an aircraft weapon in favor of the guided
air-to-air missileAn air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...
s then becoming available. The Mk 4 found other uses, however, as an air-to-ground weapon, particularly for the new breed of armed
helicopterA helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
. A volley of FFARs was as devastating as a heavy
cannonA cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
with far less weight and recoil, and in the ground-attack role its marginal long-range accuracy was less important. It was fitted with a more powerful motor to become the
Mk 40. The Mk 40 was a universal motor developed from the Mk 4 2.75 FFAR, and could be fitted with different warheads depending on the mission. Pods (typically carrying seven or 19 rockets) were created for various applications, and a wide variety of specialized warheads were developed for anti-personnel, anti-tank, and target-marking use.
The FFAR has been developed into the modern
Hydra 70The Hydra 70 rocket is a weapon derived from the 70 mm Mk 4/Mk 40 Folding-Fin Aerial Rocket developed by the United States Navy for use as a free-flight aerial rocket in the late 1940s.-Overview:...
series, which is still in service.
US Mk 40 FFAR Launchers
The United States was the primary user of this type of weapon and developed a number of different launching pods for it. Initially pods were intended to be disposed of by launching aircraft, either in flight or on the ground following a mission. With the advent of the armed helicopter, the need for launching pods that were reusable became apparent. Though the rocket was initially developed by the US Navy, the US Air Force and later US Army were most responsible for the development of rocket pods for all services. These pods are described as follows:
- Launchers designated under the US Air Force system:
| Designation |
Description |
| LAU-3/A |
19-Tube 70 mm (2.75”) rocket launcher |
| LAU-3A/A |
LAU-3/A variant; differences unknown |
| LAU-3B/A |
LAU-3A/A variant; differences unknown; US Army XM159 |
| LAU-3C/A |
LAU-3B/A variant; supports single or ripple fire |
| LAU-3D/A |
LAU-3C/A variant; differences unknown |
| LAU-32/A |
7-Tube 70 mm (2.75”) rocket launcher |
| LAU-32A/A |
LAU-32/A variant; differences unknown; US Army XM157A |
| LAU-32B/A |
LAU-32A/A variant; differences unknown |
| LAU-49/A |
7-Tube 70 mm (2.75”) rocket launcher |
| LAU-51/A |
19-Tube 70 mm (2.75”) rocket launcher |
| LAU-59/A |
7-Tube 70 mm (2.75”) rocket launcher |
| LAU-60/A |
19-Tube 70 mm (2.75”) rocket launcher; similar to LAU-3/A series except in the position of the grounding safety device |
| LAU-61/A |
19-Tube 70 mm (2.75”) rocket launcher; US Army M159A1 |
| LAU-61A/A |
LAU-61/A variant; differences unknown |
| LAU-61B/A |
LAU-61A/A variant; differences unknown |
| LAU-68/A |
7-Tube 70 mm (2.75”) rocket launcher; US Army M158A1 |
| LAU-68A/A |
LAU-68/A variant; differences unknown |
| LAU-68B/A |
LAU-68A/A variant; differences unknown |
| LAU-68C/A |
LAU-68/A variant; differences unknown |
| LAU-69/A |
19-Tube 70 mm (2.75”) rocket launcher; US Army M200A1 |
- Launchers designated under the US Army system:
| Designation |
Description |
| XM141 |
Launcher, 2.75-inch Rocket, Seven-Tube, Reloadable, Reusable; 7-Tube 70 mm (2.75”) rocket launcher |
| XM157A |
7-Tube 70 mm (2.75”) rocket launcher; not compatible w/ Mk 66 rocket motor; USAF LAU-32A/A |
| XM157B |
XM157A variant; longer launch tubes, capable of further mounting an XM118 dispenser |
| XM158/M158 |
Launcher, 2.75-inch Rocket, Seven-Tube, Reloadable, Reusable, Repairable; 7-Tube 70 mm (2.75”) rocket launcher |
| M158A1 |
M158 variant; modified hardback mount; USAF LAU-68/A |
| XM159 |
Launcher, 2.75-inch FFAR, 19-Tube, Reloadable, Reusable, Not Repairable; 19-Tube 70 mm (2.75”) rocket launcher; USAF LAU-3B/A |
| XM159B/C |
XM159 variants; differences unknown |
| M159 |
19-Tube 70 mm (2.75”) rocket launcher; type standardization of what XM159 unknown |
| M159A1 |
M159 variant; differences unknown; USAF LAU-61/A |
| XM200/M200 |
19-Tube 70 mm (2.75”) rocket launcher |
| M200A1 |
M200 variant; differences unknown; USAF LAU-69/A |
| MA-2A |
2-Tube rocket launcher |
Early
UH-1B/UH-1CThe Bell UH-1 Iroquois is a military helicopter powered by a single, turboshaft engine, with a two-bladed main rotor and tail rotor. The helicopter was developed by Bell Helicopter to meet the United States Army's requirement for a medical evacuation and utility helicopter in 1952, and first flew...
Gunships had the XM-3 Subsystem using paired 24 round rectangular launchers mounted near the back edge of the sliding side doors. These pods were ground reloadable and were semi-permanent aircraft parts. The mounting point had been used to mount booms for 3
SS-11SS.11 is the designation of the Nord Aviation MCLOS wire-guided anti-tank missile. In American service the missile was designated the AGM-22. The missile entered service with the French Army in 1956. Production of the SS.11 ceased some time in the 1980s but in 1978 168,450 missiles had been produced...
Launchers on each side for anti-tank missions. The co-pilot had a roof mounted sight and control box to fire these. Later UH-1C and D aircraft had a mount on each side to carry a 7 round pod coupled with paired
M-60D machine gunsThe M60 is a family of American general-purpose machine guns firing 7.62×51mm NATO cartridges from a disintegrating belt of M13 links...
. Some carried
M-134 MinigunsThe Minigun is a 7.62 mm, multi-barrel heavy machine gun with a high rate of fire , employing Gatling-style rotating barrels with an external power source...
with 3000 rounds per gun instead, though these aircraft were normally used by Air Cavalry units, not the
Aerial Rocket ArtilleryAlthough sometimes used as a generic term for any armed helicopters, the term Aerial Rocket Artillery refers specifically to the armed helicopter units which were organic to the division artillery of the United States Army’s two airmobile divisions during the Vietnam War...
(ARA) units.
Also various ground launchers using discarded aircraft pods were used for
fire baseA fire support base is a military encampment designed to provide indirect fire artillery fire support to infantry operating in areas beyond the normal range of direct fire support from their own base camps....
defence. A towed 6 x 19 round pod configuration called a Slammer was tested for airborne infantry support. The range was approximately 7000 meters using Hydra 70 family rockets.
Warheads for the Mk 40 Motor
With the development of the Mk 40 Mod 0 universal motor came the development of a considerable number of different warheads, as well as, a number of different fuzing options. A list of those warheads believed to be developed before the replacement of the Mk 40 motor with the Mk 66 motor is as follows:
Fuzing Options
| # |
Designation |
Description |
| 1 |
M423 |
Point Detonating |
| 2 |
XM438/M438 |
Point Detonating |
| 3 |
Mk 352 Mod 0/1/2 |
Point Detonating |
| 4 |
M429 |
Proximity Airburst |
| 5 |
M442 |
Airburst, Motor-Burnout Delay |
| 6 |
Model 113A |
Airburst, Motor-Burnout Delay |
US military Warheads
| Designation |
Description |
Fuzing Options |
| XM80 |
Submunition warhead w/ 32 XM100 CS canisters |
Unknown, believed to have an integral fuze |
| XM99 |
Submunition warhead w/ 32 XM100 CS canisters; simplified XM80 |
Unknown, believed to have an integral fuze |
| M151 |
High Explosive (HE) |
1,3,4,5 |
| M152 |
High Explosive (HE) w/ red smoke marker |
1,3,4,5 |
| M153 |
High Explosive (HE) w/ yellow smoke marker |
1,3,4,5 |
| M156 |
White Phosphorus (WP) |
1,3,4,5 |
| XM157 |
Red smoke; unknown compound |
1,3,4,5 |
| XM158 |
Yellow smoke; unknown compound |
1,3,4,5 |
| M247 |
High-Explosive Anti-Tank (HEAT)/High-Explosive Dual Purpose (HEDP) |
2 (Integral to Warhead) |
| M257 |
Parachute Illumination |
5 (Integral to Warhead) |
| Mk 67 Mod 0 |
White Phosphorus (WP) |
1,3,4,5 |
| Mk 67 Mod 1 |
Red Phosphorus (RP) |
1,3,4,5 |
| WDU-4/A |
APERS warhead w/ unknown number of flechettes of unknown weight |
11 (Integral to Warhead) |
See also
- List of rockets
- SNEB
The SNEB rocket is an unguided air-to-ground rocket projectile manufactured by the French company TDA Armements, designed for launch by combat aircraft and helicopters. Two other rockets were developed in the and caliber...
- Hydra 70
The Hydra 70 rocket is a weapon derived from the 70 mm Mk 4/Mk 40 Folding-Fin Aerial Rocket developed by the United States Navy for use as a free-flight aerial rocket in the late 1940s.-Overview:...
- CRV-7
- Aerial Rocket Artillery
Although sometimes used as a generic term for any armed helicopters, the term Aerial Rocket Artillery refers specifically to the armed helicopter units which were organic to the division artillery of the United States Army’s two airmobile divisions during the Vietnam War...
- List of U.S. Army Rocket Launchers By Model Number
- LOCAT
The Low-Cost Aerial Target, or LOCAT, was designed as an inexpensive target rocket for use by the United States Army during the late 1960s. The missile was tested by the U.S...
- used three FFAR rockets
External Links