Skinner, convinced that his idea had merit, contacted members of the National Inventors Council, who were startled by the proposal and rejected the idea with the comment that it was unrelated to national defense. Undeterred, Skinner made his proposal to the NDRC on June 9, 1941, but again he received a polite ‘No.’

Subscribe Today

• Did you enjoy our article?
• Read more in Aviation History magazine
• Subscribe online and save nearly 40%!!!
 

News of the Pearl Harbor attack sparked Skinner to resume his work. He filmed his pigeons in action and again contacted the NDRC, and this time government scientists showed mild interest but felt it was a long shot. When A.D. Hyde, then head of the mechanical division of General Mills Inc., heard about the revolutionary idea, he was at first skeptical that pigeons could be trained as flying suicide bombs. However, he thought Skinner’s reasoning was sound and persuaded the company’s top management to back the project with technical help until it could be turned over to a government agency.

With this support, Skinner’s system was refined. The previous harness was discarded in favor of a more practical lens and screen grid with a special servo-control mechanism. The force of the pigeon’s pecking motion was increased by running a bomb’s gyro and controls in a vacuum and by placing valves behind the top, bottom and sides of the flexible screen. When the pigeon tapped one of these valves, it opened, permitting air pressure to build up in the system and operate the fins on the bomb. When the target image was at dead center and the pigeon pecked at dead center, all the valves opened an equal amount and the setting was unchanged.

At this stage, the project showed enough promise that the newly formed Office of Scientific Research and Development (OSRD) awarded Skinner a contract in June 1943 under the name of Project Pigeon for ‘a homing device.’ The inventor ‘recruited’ a squadron of 64 pigeons (40 homers and 24 ordinary pigeons) from local sources and began their training. The birds were left without food for 36 hours, then placed in a cage with some grain about 30 minutes a day.

The target for the actual bombing experiments, to be located in Florida, was a white pyramid on a green field, so Skinner used a screen of white triangles cut into green paper. Once a bird learned that pecking the white pyramids would produce a few kernels of grain, it was conditioned to expect to be fed when he saw them. As soon as the bird had learned to break through light paper, heavier sheets were substituted. Eventually the pigeon was pecking with the force of a miniature air hammer.

Once a bird had completed this ‘primary’ training, it was graduated to an advanced trainer. This was a lightproof box mounted over a projection screen. A moving picture of a ground target appeared on this screen, and whenever the pigeon pecked it on the screen it caused an electrical contact to close and a small drawer to pop out containing kernels of grain.

This training worked well for a time, but the pigeons quickly learned they could get the grain no matter where they pecked the screen and began to disregard the target itself. Skinner outsmarted them by crossing two beams of light at right angles in front of the image. From then on, a pigeon had to peck the target image at dead center in order to break both beams of light and actuate a photoelectric relay to release the food.

Skinner then added a new tactic. He found he could feed the birds at regular time intervals or after a certain number of pecks. After a while, the pigeons learned to rap out as many as four pecks a second for more than two minutes without a break, and would work feverishly to prevent the target image from moving off dead center.

In one final test, Skinner put each bird into a hand-operated trainer. A person sat behind each pigeon and moved a color photo projected on the screen, at the same time operating the food magazine. The pigeon had to peck correctly or he got no food at all. According to the report on these experiments: ‘There wasn’t a single washout in the entire class of 64. Every bird earned his wings with an A grade.’

Help HistoryNet by bookmarking to