America’s first combat rockets came from a secret hangar three miles from this Delaware beach

The 4146th Unit’s Revolutionary Air-Launched Rockets at Dover

In 1944, a top-secret war project took shape at Dover Army Airfield in Delaware.

The 4146th Base Unit set up shop in Hangar 1301, just miles from Kitts Hummock, with one goal: make rockets work on planes. By March, their first rockets hit a Japanese airfield on Hainan Island.

Soon after, engineer Roy Healy flew to Burma to arm P-51s with these new weapons. Back in Europe, P-47 Thunderbolts used Dover’s 5-inch rockets to blow up German tanks and trains.

These weapons changed air combat forever. The hangar still stands today, holding the story of how a small Delaware team helped win the war.

American Rocket Experts Needed a Home Base

Early in World War II, the Army tested rockets at various locations, mainly at Aberdeen in Maryland. Test pilots flew P-40 fighters with rockets from Ohio to Maryland just to fire them.

By 1943, military leaders saw rockets could be game-changers but needed work.

After meetings in late 1943, the Ordnance Department asked the Army Air Force on January 25, 1944, to create a special unit at Dover Army Air Field to fix these problems.

Uncle Sam Created a Rocket Squad in Spring 1944

The Army Air Force started a fast-track rocket program on April 1, 1944.

They made it official on April 24 by forming the 732nd Army Air Force Base Unit under Army Material Command. Their job was to figure out how to put rockets on planes and make them work right.

The team studied the existing 4. 5-inch launcher and worked on making launchers for bigger rockets up to 16 inches across.

They also tried to create adjustable launchers that could fire in different directions.

They Built a Massive Secret Workshop Near the Beach

Dover’s rocket team worked in Hangar 1301, a huge building that had everything they needed. The hangar was 155 feet wide, 160 feet deep, with a 42-foot-high steel roof on concrete supports.

The area included offices, barracks, a mess hall, and ammo storage.

About ten miles away by the Delaware River, they built a firing range with two areas – one for testing accuracy and another for testing explosives at night. The range sat in open swampland with a tower and mess hall.

Rockets Hit Enemy Targets Before Dover Was Ready

The first combat rockets went to China in October 1943 while workers were still setting up the Dover site. The military sent 2,900 rockets and launchers for P-40 fighters to the China-Burma-India area.

After months of training, on March 4, 1944, eight planes from the 74th Fighter Squadron attacked an airfield on Hainan Island. Four planes had problems, but the other four fired six rockets each.

They tore up the airfield, blowing up vehicles and planes on the ground.

The Team Got a New Name and Bigger Goals

Military leaders changed the unit from the 732nd to the 4146th Army Air Force Base Unit on August 31, 1944. Their job grew to include studying, testing, and improving all kinds of rocket weapons for American planes.

The team worked on rocket launchers for bombers and systems that could fire from different positions. They studied captured German and Russian rocket bombs to learn from enemy designs.

They also worked on controlled rocket bombs that could be steered toward targets.

A Civilian Engineer Brought Rockets to the Jungle

Roy Healy, a civilian engineer from Dover, flew to Burma in July 1944 for a four-month job. He put rocket launchers on fighter planes and taught pilots and ground crews how to use them against Japanese forces.

Healy helped change P-51A fighters so they could carry both bombs and rocket launchers at once. He also worked on a fast-firing rocket launcher for B-25 bombers.

This launcher was designed at Dover but had problems with parts getting damaged by rocket exhaust and poor-quality plastic tubes.

Plans Changed When German Targets Got Mobile

The 4146th team put 5.0-inch rockets on planes headed to Britain on June 28, 1944.

These rockets were meant to destroy German V-weapon sites threatening London. But reports showed the Germans switched to mobile launch ramps instead of concrete bunkers.

These mobile sites were hard to find and could be hit with regular bombs when spotted.

The mission changed to give P-47 Thunderbolt fighters rockets for hitting battlefield targets like tanks and gun positions that bombers struggled to destroy.

Fighter Pilots Blew Up Trains With New Weapons

The 513th Squadron of the 408th Group got picked to use the rocket-equipped P-47 Thunderbolts. The Dover team added 5.0-inch rockets to their planes and trained the crews how to attack ground targets.

During July 1944, the squadron flew three rocket missions over Germany and occupied Europe.

On their first mission, they destroyed many locomotives vital to German supply lines. This made them the first unit in the Ninth Air Force to use air-to-ground unguided rockets during World War II.

California Joined the Secret Rocket Program

As Dover’s program grew, they needed more testing space and to be closer to manufacturers. In September 1944, they set up a rocket range at the Material Command Fighter Test Base in Muroc, California.

The California operation stayed under the control of the 4146th at Dover. Scientists at the California Institute of Technology created a successful 5.0-inch rocket with the speed and power the Air Force needed.

This rocket was first planned for German V-weapon sites but soon found many more uses on the battlefield.

Combat Experience Made Better Rocket Designs

The 4146th staff fixed problems with their launchers based on what they learned from the Burma missions. They solved issues with rocket exhaust damaging parts and replaced the weak plastic launching tubes.

Dover’s rockets could destroy heavily armored targets like German Tiger tanks, locomotives, and armored vehicles. Pilots called the High Velocity Aircraft Rockets “Holy Moses” because of how they blew things up.

The technology let small fighter planes attack targets that previously needed heavy bombers to destroy.

Dover’s Rocket Lab Changed Modern Warfare

The 4146th Base Unit created a whole new way of fighting from the air. Their cheap, effective rockets turned ordinary fighter planes into tank-killers and bunker-busters.

The air-launched rockets let planes attack targets from farther away, keeping pilots safer from ground fire. This technology led to the electronic targeting systems used in later wars.

The lessons learned at Dover shaped how rockets were used in the Korean War and beyond.

This small team working in a hangar near the Delaware coast built the foundation for modern air-to-ground weapons that are still used today.

Visiting Kitts Hummock, Delaware

You can explore the history of Dover Army Airfield’s secret rocket program at the Air Mobility Command Museum on 1301 Heritage Rd.

The museum is free with free parking and open Wednesday through Sunday, 9 a.m. to 4 p.m. Enter through the museum gate off Route 9 at Exit 91.

On Open Cockpit Day every third Saturday from April through October, retired crew members give tours inside the aircraft from 10 a.m. to 3 p. m.

This article was created with AI assistance and human editing.

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