How The CBU-105 Works: The World's Most Advanced Cluster Munition

The CBU-105 Sensor Fuzed Weapon is a precision-guided cluster bomb. It consists of an SUU-66 dispenser loaded with 10 submunitions (the BLU-108), which together release 40 target-seeking warheads designed to destroy armored vehicles and tanks.

The CBU-105 is not a single bomb, but a smart weapon system. It is essentially a standard CBU-97 cluster bomb fitted with a special guidance tail kit called the Wind Corrected Munitions Dispenser (WCMD).

This combination turns a dumb, free-falling cluster bomb into a precision-guided weapon.

Here is the step-by-step process of how it functions:

1. Launch and Guidance (The WCMD Tail Kit): The CBU-105 is dropped from an aircraft (like a B-1, B-52, or F-15E) at medium to high altitude.

Once released, the WCMD tail kit activates. It uses an inertial navigation system (INS) and GPS to know its exact position and the target’s coordinates.

The tail kit has small fins that move to correct for wind drift and other atmospheric conditions.

This ensures the weapon flies a precise trajectory to the designated aim point, rather than being blown off course like a standard unguided bomb.

2. Dispensing the Submunitions (The CBU-97 Body): As the CBU-105 reaches the calculated point above the target area, the WCMD triggers the CBU-97’s dispenser mechanism.

The outer casing of the bomb splits open along its length (a “clamshell” opening).

Inside are 40 individual submunitions, each about the size of a soda can. A small explosive charge in the dispenser pushes these 40 submunitions out the back of the opening casing.

3. The Submunitions (BLU-108B Sensor Fuzed Weapons): Each of the 40 submunitions is a BLU-108B. This is the “smart” part of the weapon. Each BLU-108B contains four smaller “skeet” warheads, for a total of 160 warheads in the entire CBU-105.

Here Are What Each BLU-108/B Does After Being Ejected:

The BLU-108B deploys a small parachute to slow its descent and stabilize it. As it descends, an onboard sensor (a laser altimeter or radar) measures its height above the ground.

At the correct altitude, a small rocket motor fires, spinning the BLU-108/B rapidly like a top.

The spinning motion flings the four “skeet” warheads outward in a circular pattern, spreading them over a wide area roughly the size of a football field.

4. The Skeet Warheads (The Kill Mechanism): Each of the four skeets is a self-contained, fire-and-forget weapon. It has its own Infrared sensor to detect the heat signature of a target (like a tank engine or exhaust).

Each of the four skeets also has an Explosive warhead. This is a shaped charge, a copper slug designed to penetrate armor and

a Parachute to slow its descent and give the sensor time to work.

The Attack Sequence

1. The skeet descends under its small parachute, spinning slowly.

2. Its Infrared sensor scans the ground in a spiral pattern, looking for a heat source that matches the signature of a vehicle (e.g., a tank, armored personnel carrier, or truck).

3. If it detects a target, the skeet fires its explosive warhead downward. The shaped charge creates a high-velocity, molten copper slug that punches through the top armor of the vehicle (the “top attack” profile), which is typically the weakest part.

4. If it does NOT detect a target, the skeet will self-destruct after a short period which is usually in a few seconds to minimize the risk of unexploded ordnance on the battlefield.

The Wind Corrected Munitions Dispenser tail kit makes it accurate in bad weather and from high altitude.

The skeets in the smart subminitions only attack vehicles, not the ground. This makes it highly effective against armored columns and strikes the weakest armor on a vehicle (the roof).

The skeets are designed to self-destruct if they don’t find a target, which is a significant improvement over older, “dumb” cluster munitions that left behind many unexploded bomblets that could kill civilians for years after a conflict.

In summary, the CBU-105 is a guided bomb that releases 40 smart submunitions, each of which deploys 4 self-guided, armor-piercing “skeets” that autonomously hunt and destroy vehicles from above.

The CBU-105 stands apart from most other cluster munitions in a few key ways. The main difference is that it is a smart or sensor-fuzed weapon, while the vast majority of cluster munitions are dumb or area-denial weapons.

Here’s a Breakdown of How It Compares:

1. The Smart vs Dumb Difference (The Biggest Factor): Most Cluster Munitions such as the CBU-87, CBU-58 and Rockeye are dumb bombs. They are dropped, open in the air, and release dozens or hundreds of small submunitions known as bomblets that fall ballistically over a wide area.

They have no guidance and no individual target detection. They simply hit whatever is below them be it a tank, a truck, or a school. This leads to high dud rates of unexploded bomblets that act like landmines for decades.

The CBU-105 is a smart weapon. It uses the WCMD tail kit for precision delivery, and its submunitions, the BLU-108B are sensor-fuzed.

Each BLU-108 canister descends by parachute, uses an infrared or laser sensor to scan the ground, and fires a self-forging fragment an explosively formed penetrator only at a valid target like a hot engine or a specific metallic shape.

If it doesn’t detect a target, it is designed to self-destruct in mid-air.

2. Target Type: Armor vs Area: Most Cluster Munitions are designed for area targets. They are excellent for saturating a large zone with explosives to kill infantry, destroy soft-skinned vehicles, or suppress an airfield. They are not very efficient against heavy armor.

The CBU-105 on the other hand is designed specifically for armored vehicles. Its sole purpose is to kill tanks and other heavy armored fighting vehicles.

It is a top-attack weapon, meaning the penetrator strikes the thin top armor of a tank, which is its most vulnerable point. It is less effective against infantry in the open or buildings.

3. Duds and Long-Term Danger: Most Cluster Munitions have notoriously high dud rates, sometimes 5 to 20% or more. This leaves hundreds of live bomblets scattered across a battlefield, killing and maiming civilians and soldiers for years after a conflict ends.

This is the primary reason over 120 countries have banned them under the Convention on Cluster Munitions.

The CBU-105 has a much lower dud rate. The BLU-108 submunitions are designed with a self-destruct mechanism.

If a skeet doesn’t find a target, it will explode in the air after a short time. While not perfect, this drastically reduces the number of unexploded submunitions left on the ground, making it significantly safer for post-conflict areas.

4. Cost and Complexity: Most Cluster Munitions are relatively cheap and simple to manufacture. A CBU-87 is a metal canister filled with bomblets and a simple fuze.

The CBU-105 is extremely expensive and complex. Each BLU-108 submunition contains a parachute, a sophisticated sensor package, a computer, and a shaped-charge warhead.

The WCMD tail kit adds even more cost. A single CBU-105 can cost hundreds of thousands of dollars, while a dumb cluster bomb might cost a fraction of that.

The CBU-105 is a high-tech, precision anti-armor weapon designed to minimize collateral damage and long-term hazards. Most other cluster munitions are cheap, dumb area-denial weapons that create severe and lasting humanitarian problems.

The CBU-105 is the exception to the rule, which is why it is still used by the US despite the general international ban on cluster munitions.

The CBU-105 is launched as a free-fall bomb from an aircraft. It is not a missile or a rocket-powered weapon. Here is the specific process involved:

It is dropped from the bomb bay or wing pylons of compatible aircraft. Common launch platforms include the B-1B Lancer, B-52 Stratofortress, and F-15E Strike Eagle.

Once released, the weapon has no engine. It relies entirely on gravity and its aerodynamic design to travel to the target.

Immediately after release, the WCMD (Wind Corrected Munitions Dispenser) tail kit activates. It uses GPS and inertial navigation to steer the bomb by moving small fins, correcting for wind drift to ensure it reaches the precise target coordinates.

At the calculated altitude and position above the target, the tail kit commands the dispenser to open, releasing the BLU-108B submunitions inside.