The Atomic Jeep!

The Willys MA and MB jeeps, along with the Ford-built GPW, played many varied and vital roles for U.S. and Allied forces on all fronts during World War II, including many its designers never envisioned. Besides, their basic purpose as 1/4-ton trucks, they also served as scout vehicles, command cars, aircraft tugs, ambulances, and fighting vehicles when fitted with various types of weaponry.

With such a successful service record, it was certainly no wonder that after the war and during late 1940s and early 1950s the U.S. military improved and upgraded the faithful Willys MB to be incorporated into the new standardized “M-series” fleet of tactical vehicles, first with the Willys MC and lastly with the Willys MD, which became the M38 and M38A1. And while these two new jeeps were every bit as rugged as versatile as their WWII predecessors, warfare had changed drastically with advent of atomic weapons, and the end of WWII ushered in the Cold War with the Soviet Union and Communist China faced off against the former Allies or “The West.”

The development of nuclear weapons during World War II, and their deployment upon the Japanese cities of Hiroshima and Nagasaki in August of 1945, resulted in a potentially cataclysmic — even possibly apocalyptic — age of warfare which exists to the present day. Entire cities could now be destroyed in seconds by a single bomb. Some military planners believed that large-scale ground armies were now all but obsolete. Still, the early versions of these weapons of mass destruction were primarily for strategic use. The two devices dropped on Japan — “Little Boy” and “Fat Man” —- were massive, each with a weight of more than 10,000 lbs. and a length of about 10 feet. Only the B-29 Superfortress had the capability of easily carrying and dropping these huge bombs, and they had little tactical use on a conventional battlefield.

However, by the early 1950s, advances in nuclear weapons development, spurred by the Cold War and the Soviet Union’s detonation of its own atomic bomb in 1949, produced a substantial reduction in the size and weight of nuclear warheads. As a result, the U.S. Army began developing and deploying tactical nuclear weapon systems in Europe, beginning with the M65 atomic cannon capable of firing nuclear shells weighing 600-800 lbs., with yields of 15 kilotons. This was followed by nuclear-tipped Corporal and Honest John missiles.

With the size (but not the destructive power) of atomic warheads shrinking, and with the North Atlantic Treaty Organization’s (NATO’s) increasing reliance on tactical nuclear weapons to offset the Soviet Union’s huge advantage in conventional forces, the U.S. Army’s Ordnance Corps began researching new weapon systems for use on a battlefield, including weapons capable of being deployed by front-line soldiers. For Ordnance officials, the ideal system would be an easily transportable weapon carrying a simple nuclear warhead with a sub-kiloton yield, and having a range of 500 to 4,000 yards. Thus, the M28/M29 Davy Crockett Weapon System was devised as a way for the U.S. Army and NATO forces to protect West Germany and Europe from potential Soviet invasion.

In 1957, the U.S. Atomic Energy Commission (AEC) directed Major General John H. Hinrichs, the Army’s chief of ordnance, to incorporate a recently developed miniature warhead into a new weapons system under the Battle Group Atomic Delivery System (BGADS) Program, which subsequently became the first project assigned to the U.S. Army Weapon Command in Rock Island, Illinois. Upon the Davy Crockett Weapon System being approved in 1958, it was produced at Picatinny Arsenal.

In regard to the Davy Crockett name, and while it doesn’t seem to be known who coined it, it does seem likely that it was inspired by the 1955 Walt Disney movie, because prior to that Davy Crockett was a rather obscure figure in U.S. history. There may also have been an ironic intent, because the Russian counterpart to the U.S. Eagle is a bear, and one of the lines of the Disney Ballad Of Davy Crockett goes: “Killed him a bear when he was only three.”

By nuclear standards the Davy Crockett was indeed only a baby — or a small firecracker. In fact, it was almost too small to actually go off. On the other hand, from a physics perspective, this was a device that was a little less than 36 inches long and weighed about 76 lbs., yet blasted out the explosive equivalent of 10 to 20 tons of TNT. By comparison, the largest conventional bomb in the U.S. arsenal had a blast yield of “only” 11 tons. And, the Davy Crockett also featured an eye-searing flash and lethal radiation.

Designated the M388, it contained a W54 nuclear warhead, which was an implosion device using plutonium-239 as its fissile material. It was as nicknamed the “Atomic Watermelon” because of its size and shape. With a small internal battery, the M388 featured a two-position height-of-burst switch, a time delay dial and a safety switch. The time dial doubled as a second safety switch, as it had a “Safe” setting. Once configured, the projectile would be fired, after which its four fins would provide stabilization during its short 100 mph flight.

The M388 could be fired from two different-sized launchers: the 120mm M28 and the 155mm M29. The former, weighing 185 lbs., had a projected range of around 1.25 miles and was equipped with a 20mm spotting rifle, from which operators fired a depleted uranium round that told them if their trajectory was on-point. The latter, with a weight of 440 lbs., had a projected range of 2.5 miles and a 37mm spotter rifle. The cartridge used depended on the launcher. The M28 was powered by a 5-kilogram cartridge, while the M29 used either a 5- or an 8-kilogram cartridge, depending on the desired range.

The launchers could be mounted on an aluminum tripod, an M116 “Husky” Amphibious Transporter, or an M38A1 jeep, which was then designated a variant M38A1D. The launcher was also mounted on the new M151 MUTT (Military Utility Tactical Truck), which was then designated a variant M151D. The launcher could also be deployed by an M113 Armored Personnel Carrier, though was not attached to the M133, but was carried as the tripod version to be set up and fired from the ground.

The M28/M29 Davy Crockett Weapon System underwent a series of tests at Forts Greely and Wainwright in Alaska, as well as at the Yuma Proving Ground in Arizona. It was also tested at the Pōhakuloa Training Area in Hawaii. Rounds containing depleted uranium were used to decrease the risk of radiation poisoning for the personnel. Oddly, there were only two officially documented tests of the actual M388 atomic projectiles: In Little Feller II in Nevada on July 7, 1962, a warhead was suspended on cables about three feet above the ground, and explosive yield was 22 tons. In Little Feller I on July 17, 1962 an M388 was fired from a stationary launcher and detonated about 20 feet above the ground at a distance of 1.7 miles from the launch point with a yield of 18 tons. Whether this distance was intentional, or a disturbing disappointment seems unclear: the M29 launcher was supposed to be able to fire the projectile over two miles, and a distance of only 1.7 miles would seem to have put the firing crew in danger, though the firing may have been remotely done.

This test was conducted in conjunction with Operation Ivy Flats, a series of maneuvers to train soldiers in nuclear battlefield conditions. Among the VIPs in attendance were Attorney General Robert F. Kennedy and presidential military advisor General Maxwell D. Taylor, who made the development of the Davy Crockett a priority when he served as Army Chief of Staff. The Little Feller tests also marked the last above-ground nuclear test at the Nevada Test Range.

After testing was completed, the Davy Crockett Weapon System was deployed around the world. The first to receive it were the U.S. Seventh Army’s infantry and armored battalions stationed in West Germany to defend the Fulda Gap, which was the expected invasion route of Warsaw Pact forces advancing west. The Davy Crockett was also issued to personnel stationed in South Korea, Guam, Hawaii and Okinawa — basically, anywhere that was threatened, or perceived as threatened — by the Soviet Union and/or Communist China.

The Davy Crockett was deployed with U.S. Army forces from 1961 to 1971. Between 1958 and 1963, 2,100 were produced at an estimated cost (excluding the warhead) of $540 million. The weapon’s non-nuclear components were manufactured at the Rock Island Arsenal in Rock Island, Illinois. The W54 warhead was designed at the Los Alamos Scientific Laboratory (now the Los Alamos National Laboratory) and built by the Atomic Energy Commission.

The Davy Crockett was operated by a three-man crew when mounted on an M38A1D jeep or M151D MUTT. After firing a spotting round from either a 20mm (M28) or a 37mm (M29) gun attached to the Davy Crockett launch tube to determine the proper distance and angle to the target, the crew inserted a propellant charge down the muzzle, followed by a metal piston, then loaded the sub-caliber spigot on the rear of the M388 projectile into the barrel of the launcher like a rifle grenade. A switch on the warhead allowed the crew to select the height of detonation.

Upon firing, the M388 left the launcher with a big bang and billow of smoke, reaching a speed of 100 mph. Since the launch tube was smooth-bore, accuracy was less than optimum. Nevertheless, what the Davy Crockett lacked in accuracy it made up for in explosive power, though the initial radiation created by the detonation of the warhead would be as lethal to the enemy as the blast and thermal shock. Since the warhead also posed a threat to the crew firing it -— in seconds a nuclear bomb would be detonating a little over a mile away — the Army directives advised firing from entrenched positions so the personnel were shielded, or from a jeep or MUTT so they could make a fast escape, “Don’t look directly at the atomic fireball” wasn’t much survival advice, nor was advising soldiers “to keep their heads down to protect themselves from the warhead’s detonation.

While the firing procedure seems fairly simple as written, in practice there were complications besides protecting yourself after firing. Before the warhead was loaded into the launcher, the timer dial had to be set, and it could only be set it to a maximum of 50 seconds. The warhead had to go off above the target and at the right height. The M388 had no computer brain or sensors, so it didn’t know when to go off, and the operator had to figure that out to a fairly high degree of accuracy.

Suppose the operator made a mistake and the warhead hit the ground? According to the manual (FM 23-30, December, 1961) it might break and wouldn’t necessarily explode. Assuming it was now in enemy territory and the enemy knew what it was, one would think they would vacate ASAP. According to the manual, SOP was to wait 30 minutes and then (presumably very carefully) recover the warhead to be serviced.

Ooooo-kay.

Because the Davy Crockett was an infantry weapon, the Army had to be careful about the level of radiation emitted by the M388. While personnel firing the weapon were given precautions to follow, the enemy, of course wasn’t; and those within 150 meters of the detonation site — besides those already vaporized by the explosion — would be exposed to enough radiation to kill them in a matter of minutes, while those at greater distances could expect to die unpleasantly anywhere from a few hours to less than two weeks after exposure.

Fortunately, the weapon was never used in any actual conflict. The U.S. Army began to wind down deployment of the Davy Crockett in 1967 with its removal from service in Europe. This left the 82nd Airborne Division’s 55th and 56th Infantry Platoons as the only remaining units with the weapon, until they were deactivated in 1968.

The Davy Crockett was officially retired from service in 1971, with Brigadier General. Alvin Cowan, assistant division commander of the 3rd Armored Division, stating that the decision was twofold. Along with the high costs and risks associated with deploying the Davy Crockett, there was always “a great fear that some sergeant would start a nuclear war.”