Wendover’s Atomic Secret
How B-29 crews trained to drop the bomb.
- By Carl Posey
- Air & Space magazine, March 2011
Wendover AFB History Office
(Page 3 of 4)
Morris "Dick" Jeppson, who as an Army lieutenant would monitor Little Boy’s pulse en route to Japan in Tibbets’ B-29, had dropped out of the California Institute of Technology for lack of funds, and wound up at the communications school at Harvard and the radar engineering school at MIT.
Leon Smith, whose career in nuclear weaponry would span decades, was a classmate. "We were trained to go anywhere and run and troubleshoot any radar," Smith explained in a 2005 Los Alamos lecture. That included the radar altimeters aboard Little Boy and Fat Man, which, with barometric switches, would trigger the bombs about 1,500 feet above the ground.
Smith recalled that, upon arriving at Wendover, a civilian asked him to take a walk with him. "He said they wanted to build a fusing system for a new weapon. I asked if this were a biological or atomic weapon. For that I received a security investigation."
BEFORE 1944 WAS OUT, the Wendover squadrons had begun a rigorous training program. For the 509th, this meant frequent flights to practice dropping inert surrogates for Little Boy and Fat Man on targets limed on the desert floor. "We didn’t know what the bomb was," recalled Herman Stanley Zahn, one of the aircraft commanders. "All we were trying to do was drop it as accurately as we could." They also rehearsed an escape maneuver, which Tibbets had designed to get the airplane as far as possible from the expected blast. This was a kind of inside-out chandelle, beginning with a diving quarter roll from which the aircraft recovered 2,000 feet lower, and headed back the way it had come.
The 216th aircraft continued drop testing, led by Major Clyde Shields, who had piloted the Silverplate prototype. The flights were staged out of Wendover and Inyokern, California, near the Navy’s China Lake weapons proving ground. Drops were made on one range a few miles south of Wendover, and another at Sandy Beach, on California’s Salton Sea.
These missions were flown without a weaponeer, but with an electronics expert to monitor the dummy. Jeppson recalled occupying a small space behind the radio operator and next to the forward bomb bay. "We were just kind of there on a little platform," he said. "The monitoring box was hooked up to three coaxial cables into the bomb bay. We sat or kneeled."
It sounds simple enough, but Major Shields’ daily summaries compose a saga of frustration. Flights were thwarted by weather. Engines failed regularly, or went asthmatic in the thin air at bombing altitude. One engine fire largely consumed a B-29 on a Wendover runway. And then there was the incident over the little desert town of Calipatria, a few miles southeast of Salton Sea. "I was on that one," Jeppson recalled. "A Little Boy. I was monitoring my circuits, fusing, batteries, typical thing, flying at 30,000 feet." Suddenly the B-29 jerked upward. An engineer, who had gotten special clearance to be on the flight to observe how the Norden bombsight handled, had mistakenly released the bomb prematurely, wrote Gordon Thomas and Max Morgan Witts in Ruin from the Air: The Enola Gay’s Atomic Mission to Hiroshima. "It sailed over the town and landed in a farmer’s field," said Jeppson. The errant Little Boy buried itself so deep that security personnel simply filled in the hole. As for the mortified engineer, when the B-29 returned to Wendover, project agents escorted him to a car, drove him to Salt Lake City, and, after telling him he could no longer visit the base, put him on a train.
For training purposes, the inert dummies were filled with cement, carefully formulated to match the density of a high explosive called Composition B. Orange-painted bombs, called pumpkins, were stuffed with several tons of Composition B—making them the largest conventional bombs in the American arsenal.
In all, Wendover-based B-29s dropped about 155 Little Boy and Fat Man dummy bombs. The crews proved more resilient than the first generation airframes. Crews began shuttling to the Martin plant in Omaha and returning with brand-new bombers—the top of the Silverplate line. Pneumatically operated bomb bay doors flicked open and closed like aluminum eyelids. All were configured to carry Little Boy or Fat Man bombs in the forward bomb bay, with the option of carrying either conventional bombs or a 600-gallon auxiliary fuel tank in the aft bay. The Wright Cyclones had been replaced with fuel-injected engines and electrically operated reversible-pitch propellers, used to brake on landing and for maneuvering on the ground.