Dean drive
Claimed reactionless drive that violated Newton's third law.
Wikipedia / Wikimedia Commons
Norman Lorimer Dean (1902–1972) was an inventor who created and promoted a device he called the Dean drive, which he claimed was a reactionless drive. According to Dean, it could produce a force in one direction while in free space, directly contradicting Newton's third law of motion. If his claims had been true, the device would have had massive implications, revolutionizing transportation, engineering, and space travel. The Dean drive gained significant attention in the 1950s and 1960s largely due to John W. Campbell, the longtime editor of *Astounding Science Fiction* magazine, who wrote about it in his columns and discussed it at conferences. Campbell believed the device worked and said he saw it operate on a bathroom scale, where the weight reading appeared to drop when the device was turned on; he published photos of the scale with the drive running and stopped. The June 1960 cover of *Astounding* even showed a submarine near Mars, supposedly powered there by a Dean drive.
Dean, who was looking for buyers for his technology, kept the details of how it worked secret, but it was said to involve asymmetrical rotating weights and produced a lot of vibration. He and Campbell argued that Newton's laws were only approximations and that Dean had discovered a fourth law of motion—a nonlinear correction that, if correct, would make a reactionless drive possible. After Campbell's initial articles, two other researchers, William O. Davis and G. Harry Stine, visited Dean and saw a demonstration. Davis wrote in the May 1962 issue of *Analog* (the renamed *Astounding*) that both he and Stine concluded they had witnessed a real anomaly and that fraud seemed unlikely. However, aerospace researcher and science fiction writer Jerry Pournelle noted that while Stine was qualified to judge the device, he was also more gullible than most.
Davis's 1962 article, "The Fourth Law of Motion," proposed a hypothesis where Dean's device could conserve momentum invisibly through "gravitational-inertial radiation," with action and reaction forces occurring out of phase with each other. A later 1976 article by Davis, "Detesters, Phasers and Dean Drives," reported that Stine built devices to test this idea and claimed they could reliably create a 3-degree phase angle in a linear system—something ordinary physics says is impossible. But they failed to reproduce the effect in a pendulum
- born
- 1902
- died
- 1972
- field
- Inventor
- nationality
- American
- known_for
- Claimed reactionless drive (Dean drive)
Lore & Background
Norman Lorimer Dean made several controlled private demonstrations of a number of different devices; however, no working models were ever demonstrated publicly or subjected to independent analysis and Dean never presented any rigorous theoretical basis for their operation. Analysts conclude that the motion seen in Dean's device demonstrations was likely reliant on asymmetrical frictional resistance between the device and the surface on which the device was set ("stick and slip"), resulting in the device moving in one direction when in operation, driven by the vibrations of the apparatus.
Dean, who was trying to find potential buyers for his technology, was secretive about the details of how it was supposed to work, but it was said to contain asymmetrical rotating weights and to generate a great deal of vibration. Dean and Campbell claimed that Newton's laws of motion were only an approximation, and that Dean had discovered a fourth law of motion. This has been described as a nonlinear correction to one of Newton's laws, which, if correct, would allegedly have rendered a reactionless drive feasible after all.
Dean was granted two U.S. patents on mechanical devices presumably related to his Dean drive claims. His first patent for a "System for converting rotary motion into unidirectional motion" was granted on May 9, 1959. Another patent for a "Variable oscillator system" was granted on May 11, 1965. These two patent designs were the only ones where Dean revealed the design details with an explanation for operation. However, the details were incomplete, and it is not possible to build a Dean drive just from the explanations in the patent.
Reader's Guide
The Dean drive is significant as a prominent example of a claimed reactionless drive that generated widespread publicity and debate, particularly within science fiction circles, but was never proven to work. Its legacy is that of an unverified device that, despite attracting interest from researchers like William O. Davis and G. Harry Stine, failed to withstand independent testing. Davis and Stine witnessed a demonstration and concluded they had witnessed a real anomaly, but later attempts to reproduce the effect in a pendulum system failed, and Dean refused to subject the original drive to a pendulum test. Later analysis has revealed that the interactions of vibration, friction, and resonance with the springs of a scale are likely the root cause of the apparent weight loss reported by Campbell and others. After Dean's death, neither the demonstration devices nor any working devices were found among his experiments. The device is now often cited in discussions of pseudoscience and unproven propulsion concepts. In 2006 a NASA technical memorandum presented the Dean drive as the most famous example of an "oscillation thruster" and examined its theoretical basis and feasibility.
Did You Know?
- The June 1960 cover of Astounding magazine featured a painting of a United States submarine near Mars, supposedly propelled there by a Dean drive.
- In 1984, physicist Amit Goswami wrote that it is now customary in science fiction circles to refer to a reactionless drive as a Dean drive.
- Dean's patented devices were later shown to develop no net weight loss over time and do not violate Newton's third law of motion.
- After Dean's death, neither the demonstration devices nor any working devices were found among his experiments.
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