The Dean drive was a device intended to be a reactionless thruster or "oscillation thruster," invented by Norman L. Dean. Dean claimed that it was able to generate a uni-directional force, in violation of Newton's Third Law of Motion. Such a violation is impossible according to known physics. While it is theoretically possible for a mass that moves in one direction to have its momentum balanced by something other than a reaction mass (e.g. see Nuclear photonic rocket), there is no known theoretical mechanism for a mass to be accelerated one way while nothing accelerates the other way, at least in flat spacetime.
An actual functioning "reactionless thruster" would have had enormous applications, completely changing human transport, engineering, space travel and more. While Dean made several demonstrations of his drive, no working model was ever verified by independent third parties.
According to Dean, his drive is a reactionless thruster, and his models were able to demonstrate this effect. He received two patents for related devices that are known to be unable to generate a uni-directional force, but he occasionally demonstrated devices that were different. Dean's claims of reactionless thrust generation have subsequently been shown to be in error; the thrust generated is understood to be reliant on friction with the surface on which the device is resting.
The Dean drive obtained a good deal of publicity in the 1950s and 1960s via the columns and conference presentations of John W. Campbell, the longtime editor of Astounding Science Fiction magazine. At that time, Campbell believed that his magazine had to change society by helping breakthrough research that was rejected by "mainstream" science, and he promoted a series of far-reaching ideas that had dubious scientific basis, like dianetics, dowsing, the Hieronymus machine, or the Dean Drive. Campbell believed that the device worked and claimed to have witnessed it operating on a bathroom scale. The weight reading on the scale appeared to decrease when the device was activated. He subsequently published photographs of the scale with the drive stopped and running. The June 1960 cover of Astounding magazine featured a painting of a United States submarine near Mars, supposedly propelled there by a Dean drive.
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.
One result of the initial articles in Campbell's magazine was that two other researchers, William O. Davis and G. Harry Stine, visited Dean and witnessed a demonstration. Results of this visit were published in the May 1962 and June 1976 issues of the magazine, the name of which had been changed by Campbell from Astounding to Analog. Davis witnessed a demonstration by Dean, and wrote: "It was the conclusion of both Harry Stine and myself that we had witnessed a real anomaly and that the possibility of fraud in the demonstration was slim." Sci-fi writer Pournelle pointed out that Stine was well qualified to make a judgment on the device, but that he was more gullible than other persons.
Davis' 1962 article was titled, "The Fourth Law of Motion", and described a hypothesis in which Dean's device (and others) could conserve momentum invisibly via "gravitational-inertial radiation". One detail of Davis' hypothesis involved the forces of action and reaction — physical bodies can respond to those forces nonsimultaneously, or "out of phase" with each other.
Davis' 1976 article, "Detesters, Phasers and Dean Drives", reported his tests with Stine, an engineer who built devices to test that aspect of the hypothesis. Stine said they were able to reliably create and reproduce a 3-degree phase angle in a linear system, which was not possible according to ordinary physics. But then they failed to reproduce the effect in a pendulum system, using a rocket-powered ballistic pendulum. The pendulum test would have proved beyond doubt that the Drive worked, but Dean refused to subject the original Dean Drive to a pendulum test. Campbell reported that he had seen the Drive subjected to a pendulum test, but Davis and Stine suspect that he only reported what Dean had told him and had never seen the actual test. Davis says the question can't be settled until the pendulum test is made. Their research was terminated in 1965 when the national economy took a downturn, and was never resumed. The 1976 article was an attempt to get research restarted, but apparently failed.
In 1978 physicist Russell Adams wrote an article in Analog. Searching in the US patent office he had found at least 50 patents of similar reactionless drives. After studying the mechanisms, he concluded that they all relied in friction against the floor they were placed on, and they would be useless in space, where you don't have friction against any surface.
In 1984, physicist Amit Goswami wrote that "Dean's machine made such a splash with readers of science fiction that it is now customary in SF circles to refer to a reactionless drive as a Dean drive."
Purported weight loss
While Dean was still alive, he made a demonstration to magazine Popular Mechanics where a version of the Dean Drive, while suspended above the ground, was able to pull a load to itself without itself being pulled toward the load. Another version of the machine was able to apply a force to a hand, without moving—yet when the machine was turned off an equivalent force applied by the hand easily moved the machine. Dr. William O. Davis, who witnessed the latter demonstration, wrote in his notebook about Dean's explanation of how the device worked, "... does not strike me as valid ... For this reason I have decided to undertake a theoretical study of dynamic systems to see if a concept can be evolved which will describe a world in which Dean's Drive can exist and yet where other known facts are not contradicted." He succeeded at devising such a concept, and it was published in Analog in 1962.
Nowadays, the interactions of vibration, friction, resonance with the springs of the scale are considered to be the root cause of the apparent weight loss reported by Campbell and other effects. Dean's patented devices, and his explanation of how his Drive was supposed to work, were later shown to develop no net weight loss over time and do not violate Newton's Third Law of Motion. Many other inventors claim to have invented similar devices, and they all still remain unproven, and lacking a solid theoretic basis.
As early as 1961 Dean was featured in Popular Mechanics Magazine. The article was titled "Engine with built in wings". In the article it describes the systems and how they might be used in every day instances and not so every day, like space travel.
According to Dean's writings and records now in possession by his son Norman Robert Dean, several groups, including Westinghouse Electric Corporation, the U.S. military, Robert L. Vesco, and the AC Spark Plug (Aeronautics Division) became interested in licensing the device. AC Spark Plug researched the technology for two years, but AC's board decided it was too much of an unknown technology to invest in.
A combination of Dean's experience of forced appropriation of his non-precessing gyroscopic inertial guidance system by the US military (for use in intercontinental ballistic missiles and submarines) and his cautious nature led him to terminate relations with his most recent interested party investment banker Robert L. Vesco who coincidently fled to Cuba in 1973.
In the 1950s Jerry Pournelle, working for an aerospace company, contacted Dean to investigate purchasing the device. Dean refused to demonstrate the device without pre-payment and promise of a Nobel prize. Pournelle's company were unwilling to pay for the right to examine the device and never saw the purported model. 3M sent representatives about the same time, and obtained similar results. Pournelle is now convinced that Dean's device never worked.
After Dean's death, neither the demonstration devices nor any working devices were found among his experiments. The demonstration devices were clearly different from the devices patented by Dean, and no diagrams were ever found for them. Consequently, it is impossible to test Dean's reported designs or devices to see if they worked as he claimed.
In 1997 physicist John G. Cramer mentioned the Dean Drive in Analog in his column "Alternate View". He said that the demonstration made to Campbell was faulty, and the drive had turned out to be bogus, like many other claims of antigravity devices.
In 1999, Dean’s son, Norman Robert “Bob” Dean, appeared at an anti-gravity conference by invitation of a group of patent holders who had created differing versions of the reactionless drives that referred to N.L. Dean in their patents. He gave a presentation about his father’s device.
In 2006 a NASA technical memorandum presented the Dean Drive as the most famous example of an "oscillation thruster" and examined its theorical basis and feasibility as a space drive. It said that "Regrettably, such devices are not breakthroughs, since they still require a connection to the ground to create net motion. The ground is the reaction mass and the frictional connection to the ground is a necessary component to its operation." NASA regularly receives proposals of similar devices, and the memo recommend that future reviews of said proposals "should require that submitters meet minimal thresholds of proof before engaging in further correspondence."
In 2009, mechanical engineer professor Provatidis published his first paper on the mechanics involved in Dean drive. He claims to have proven that the device practically works like a catapult while a variable angular velocity can only control the smoothness of the object velocity to which the drive is attached. Moreover, as the net impulse produced by rotating mass particles along a circle is zero (in Dean drive), he proposed the transformation of the aforementioned circle to a figure-eight-shaped curve (symbol of infinity) in which only the upper (or lower) 180 degrees are drawn thus causing anti-gravity effects.
In 2012 a researcher attempting to characterize the Woodward effect, another proposed reactionless drive effect, has stated that she has designed her experiments to specifically exclude any "Dean drive" effects which she considers "spurious noise".
- Eric Laithwaite was a UK inventor who made similar claims.
- Reactionless drive
- Stochastic Electrodynamics
- George Arfken (1 January 1984). University Physics. Academic Press. pp. 181–182. ISBN 978-0-323-14202-1. Retrieved 28 May 2013.
- "Engine With Built-in Wings". Popular Mechanics. Sept 1961.
- "Detesters, Phasers and Dean Drives". Analog. June 1976.
- Mills, Marc G.; Thomas, Nicholas E. (July 2006). "Responding to Mechanical Antigravity". 42nd Joint Propulsion Conference and Exhibit. NASA. Archived from the original on 2011-10-30.
- Goswami, Amit (2000). The Physicists' View of Nature. Springer. p. 60. ISBN 0-306-46450-0.
- Gary Westfahl (1998). The Mechanics of Wonder: The Creation of the Idea of Science Fiction. Liverpool University Press. pp. 278–279. ISBN 978-0-85323-563-7. Retrieved 28 May 2013.
- L. Sprague de Camp (29 September 2011). Time and Chance: An Autobiography. Orion. pp. 109–110. ISBN 978-0-575-10366-5. Retrieved 28 May 2013.
- Arthur C. Clarke (29 September 2011). Astounding Days. Orion. p. 118. ISBN 978-0-575-12187-4. Retrieved 28 May 2013.
- Cramer, John G. (1997). "Antigravity Sightings". Analog Science Fiction & Fact Magazine. Retrieved 2010-07-15.
- "Astounding/Analog Science Fact & Fiction, June 1960". Internet Speculative Fiction Database (ISFDB). Retrieved 2010-07-15. Cover picture by John Schoenherr; the submarine is designated "USSS-1" and 578, so presumably modeled on USS Skate (SSN-578).
- Pournelle, Jerry (May 23, 2008). "The Dean Drive and other Reactionless Drives".
- Russell E. Adams, Jr, "The Bootstrap Effect", Analog, April 1978
- Amit Goswami; Maggie Goswami (July 1985). The cosmic dancers: exploring the science of science fiction. McGraw-Hill. p. 23. ISBN 978-0-07-023867-1. Retrieved 28 May 2013.
- "The Fourth Law of Motion". Analog. May 1962.
- Provatidis, Christopher, G. (2009). "Some issues on mechanical antigravity (inertial propulsion) mechanisms using two contra-rotating masses", 3rd International Conference on Experiments/Process/System Modeling/Simulation & Optimization (3rd IC-EpsMsO), Athens, 8–11 July; also Theory of Mechanisms and Machines, 8(1), April 2010: pp. 34–41: http://tmm.spbstu.ru/15/Provatidis_15.pdf; also: Provatidis, Christopher, G. (2011). "A Study of the Mechanics of an Oscillating Mechanism", International Journal of Mechanics, 5(4), October 2011: pp. 263-274: http://www.naun.org/journals/mechanics/17-093.pdf
- Provatidis, Christopher, G. (2009), "A novel mechanism to produce figure-eight-shaped closed curves in the three-dimensional space", (ibid.)
- Fearn, Heidi; Woodward, James F. (2013). "Experimental Null test of a Mach Effect Thruster". arXiv:1301.6178 [physics.ins-det].
- Dean Space Drive - A website (apparently maintained by the Dean family) detailing additional materials and background information on Norman Dean and his device.
- Dean Drive and Other Reactionless Drives, a narrative by Jerry Pournelle describing his brief investigation of the Dean Drive.
- Nicholas Thomas. "'Breakthroughs' commonly submitted to NASA". Archived from the original on 2006-02-11. Explains an Oscillation Thruster.
- Patent 02886976
- Patent 03182517