Unconventional Flying Objects: A Scientific Analysis

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Paul Hill was a well-respected NASA scientist when, in the early 1950s, he had a UFO sighting. Soon after, he built the first flying platform and was able to duplicate the UFO's tilt-to-control maneuvers. Official policy, however, prevented him from proclaiming his findings. "I was destined," says Hill, "to remain as unidentified as the flying objects."

For the next twenty-five years, Hill acted as an unofficial clearing house at NASA, collecting and analyzing sightings' reports for physical properties, propulsion possibilities, dynamics, etc. To refute claims that UFOs defy the laws of physics, he had to make "technological sense ... of the unconventional object."

After his retirement from NASA, Hill finally completed his remarkable analysis. In Unconventional Flying Objects, published posthumously, he presents his findings that UFOs "obey, not defy, the laws of physics." Vindicating his own sighting and thousands of others, he proves that UFO technology is not only explainable, but attainable.

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Editorial Reviews

From the Publisher

Paul Hill has done a masterful job ferreting out the basic science and technology behind the elusive UFO characteristics . . . Perhaps this book will help bring solid consideration for making all that is known about extraterrestrial craft publicly available. --Edgar Mitchell, Sc.D., Apollo 14 Astronaut

Paul Hill has done a masterful job ferreting out the basic science and technology behind the elusive UFO characteristics . . . Perhaps this book will help bring solid consideration for making all that is known about extraterrestrial craft publicly available. --Edgar Mitchell, Sc.D., Apollo 14 Astronaut

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Product Details

  • ISBN-13: 9781571740274
  • Publisher: Hampton Roads Publishing Company, Inc.
  • Publication date: 12/28/1995
  • Edition description: New Edition
  • Pages: 432
  • Product dimensions: 6.10 (w) x 8.90 (h) x 1.10 (d)

Read an Excerpt


a scientific analysis


Hampton Roads Publishing Company, Inc.

Copyright © 1995 Julie M. Hill
All rights reserved.
ISBN: 978-1-61283-181-7


Physical Properties and Effects

A. Introductory Statement

Physical evidence exists that UFOs are real, solid, massive, machine-like vehicles, as evidenced, for example, by their retractable landing gear and the deep impressions made by the landing gear in various solid-earth surfaces.

Sighting records show, however, that they often do not land, but on close approach to the earth hover a few feet above its surface. If they stay any length of time, the plant roots and soil humus below the UFO are apt to be scorched and chemically altered, as may be tree branches and trunks on the side facing the UFO. Light-weight green plants, such as grass, are more apt to be only wilted or unaffected.

People are not immune. They sometimes receive ultraviolet eye and skin burns resembling sunburn. Very close observers have received burns ranging from flesh burns to injuries with all the symptoms of radiation poisoning.

B. Evidence of Weight and Massiveness


In Flying Saucers Over Spain, UFO student Antonio Rebera gives an interesting account of the landing of a saucer on February 6, 1966, at Aluche, Spain, a suburb of Madrid with new apartment buildings interspersed with open spaces. The saucer landed in an open space, perhaps larger than a city block. From the street bordering the clear area, witness Jose Louis Jordan watched a luminous, fiery disk approach, hover momentarily, and land at about 8:00 P.M. During its approach, it lowered a tripod landing gear which it sat down on. The saucer was shaped like two big rimmed pie pans placed rim-to-rim and was estimated to be 10 to 12 meters in diameter. In a few minutes it rose, the landing gear disappearing as it did so. Sr. Jordan was overcome by the experience. Instinctively he tried to locate other witnesses, but he was too late. The vehicle had gone, but it had left impressive evidence of its visit. Pressed into the hard Spanish soil were three neat footprints of the landing gear, arranged in an equilateral triangle of 6 meters (19.7 feet), imprint to imprint. The prints were rectangular with rounded corners and each had a raised X-mark of half-round cross section on the bottom. The dimensions were given in centimeters.

The prints were therefore about 6 by 12 inches in plan and nearly 5 inches deep, although one was shallower. The raised X-print looked something like the traction markings on a tire tread. Hundreds of Madrillenos came to witness the UFO tracks. They had clearly been made by a heavy or massive vehicle in a vertical landing, as the prints were clear-cut.


Near Gault, Ontario, on July, 30, 1957, 15-year-old Ted Stevens stood and watched a round, silver-colored object hover for 40 minutes before it landed in a corn-stubble field about 300 yards distant, according UFO, The Whole Story, by Coral and Jim Lorenzen. A burned circle and two impressions in the ground remained as evidence of the landing. Investigators of the incident were hard put to explain the impressions as the ground was nearly rock-hard, and the prints were pressed into the ground, not dug. The consensus of all who studied the evidence was that something very heavy had rested there.


On a late afternoon (5:50 P.M.) of April 1964, police patrolman Lonnie Zamora of Socorro, New Mexico, drove his patrol car off the highway and followed a desert trail to investigate a roar and flash of blue flame near a dynamite shack. This story is detailed in Flying Saucers: The Startling Evidence of the Invasion From Outer Space, by Coral Lorenzen (pp. 218-21).

As Zamora approached the area where the shack was located, he caught a glimpse of a white vehicle standing on end (which he first took to be a car) with two small individuals standing by it dressed in what looked like white mechanics' uniforms. One of the figures appeared to turn and look toward him. Zamora called fellow officer Sergeant Chavez for assistance. He then drove up and across the next mesa, where he stopped and got out. Taking three steps toward the gully ahead, he could again see the vehicle, which was not a car but a cylindrical object standing on end. Suddenly there was a roar from the object as it kicked up dust. Zamora threw himself to the ground and, looking up, saw the vehicle rising on a very shallow, slanted trajectory. He got up and started to run, but hit the car, knocking off his glasses. The roar ceased, giving way to a high-pitched whine as the object cleared the dynamite shack by only about 20 feet.

Sergeant Chavez soon arrived, and the two went down to the gully to inspect the area. A mesquite bush at the center of the landing site was still burning. There were four 8×l2-inch wedge-shaped depressions, 3 to 4 inches deep. The ground was very uneven, and the arrangement of the marks "indicated self-leveling gear."

Jacques Vallee, a scientific conservative, also investigated this landing. In Challenge to Science, he says, "The investigation also revealed that the craft was not built by amateurs; it had landed on uneven terrain, firmly set on four legs of unequal length in such a way as to put the center of gravity in the best position" (p. 35).


According to Flying Saucers: Serious Business (pp. 58-59) and other sources, Marius Dewilde, who lived about a mile from Quaroble, France, went to bed at 10:15 P.M. on September 10, 1954. A few minutes later he got up and went to see why his dog was howling. Outside, his dog came crawling up to him, and he switched on his flashlight to look around. He could make out, some distance from the house, a large dark object on the railroad. Only 20 feet away, in the beam of his light, he saw two humanoid figures about 3½ feet tall and wearing shiny helmets similar to those worn by divers. Associating the figures with the object on the tracks, Dewilde ran to interpose himself between the figures and the tracks. At that time a bright beam from the object stopped him. He told police, "I could only stand there as if paralyzed. I could not move my arms or legs. I could not yell. I was helpless when that light was on me."

He saw an opening appear in the dark object, and shortly thereafter it left by rising straight up.

The incident was investigated by the French Air Force and Department of Territorial Security. Where Dewilde said the object rested, five deep indentations were pressed into the wooden crossties. Experts who examined the indentations and the crosstie material estimated the weight of the object to be 30 tons. Dewilde described the object as approximately football-shaped, roughly 6 meters long by 3 meters high.

In all of these instances, the objects were clearly very heavy to have left such impressive prints. In the last case, we have what should be a reliable minimum weight estimate of 30 tons because the crumbling strength of various woods is well known.

For the three centuries since Newton's time it has been known that each pound of weight is due to the acceleration of gravity acting on each unit of mass. Thus we must conclude that UFOs are both heavy and massive, at least when landed. While this is a simple concept, it is too important to pass over lightly. When this concept is taken at face value, it can be immediately deduced that each of the UFOs which made the prints, being heavy and massive, required a lot of thrust to lift off and even more to accelerate. The strong implication is that their invisible power plants and thrust generators are powerful ones.

Since we are fortunate enough to have estimated dimensions from the Quaroble case, let us check on the mass density to get a comparison with Earthcraft. If we make the logical assumption that the UFO shape was ellipsoidal with the 6 meters being the axial length 1 and 3 meters the cross-diameter d, the volume is given by


Assuming short tons, of 2000 lb./ton, 30 tons converts to 27,200 kilograms of mass. To get mass density, we divide mass by volume and get 965 kilograms per cubic meter. Since water has a mass density of 1000 kg per cubic meter, the Quaroble UFO was about 96 percent as dense as water, very close to the density of a submarine. It is several times more dense than a jet aircraft.

This density, if representative, could explain the observed underwater operation and the apparent multiphibious nature of the UFO. It's particularly important that we take note that an object of this density, equipped with a retractable landing gear, is a very substantial "flying" machine made to land on land and having properties consistent with operation from water surfaces or even underwater.

In some cases, saucer UFOs land in swampy areas by simply making a belly landing. Such a landing distributes the load and leaves a shallow, saucer-like depression, sometimes with swirled-down reeds or grass, that is called a saucer-nest. Flying Saucers: Here and Now presents a photo of such a nest (Edwards 3235).

According to the July/August 1974 APRO Bulletin, APRO has adopted as one of its goals the analysis of ground traces left by UFOs to determine their weight. The technique will involve the taking of core samples and penetrometer readings at the site, together with laboratory analysis in Tucson. The soil bearing strength will be carefully measured and the UFO weight computed from this data and the dimensions of the impressions. This realistic program should furnish needed data.

The landed data shows that UFOs are massive while landed. In Section VII we shall encounter impressive evidence that UFOs use high thrust while in flight, which is highly inconsistent with the assumption made by some UFO investigators that UFOs reduce mass to zero. With no mass they would not need and could not use high thrust. In Section II, where we will address performance, we shall see that observed accelerations are high, but not so high as to require an escalation of hypothesis to zero mass, or even to mass control for their explanation. In other words, all can be explained by ordinary mass densities and excellent thrusting capability. In this view, UFOs are very good machines, without miracles.

For those interested in the theory on which some have based their mass-control ideas, let me add that it is an interpretation of Einstein's general theory of relativity, and other "metric" theories of gravitation. Einstein related the property of local inertial mass to the mass of the universe, as Mach did before him and others since. The property of local inertial mass depends on the action of all the mass and gravity of the universe. The interpreters reason logically that if there were a perfect gravity shield surrounding local matter its inertial mass would be zero.

Physicists have hunted for a gravity shield for over half a century and have determined in the laboratory to high precision that no matter forms a gravity shield to the slightest measurable degree. Astronomers have been in agreement with this result because they know that during a solar eclipse, if the interposition of the mass of the moon between the sun and the earth had any shielding effect, the earth's orbit would be perturbed. It is not.

The acceptance of twentieth-century science at face value is at experimental odds with basing mass control on the shielding possibility. I sometimes wonder about the possibility of an alternate idea. Possibly inertial mass could be reduced, if not by shielding, by the superposition of a negative gravity field of antigravitons on the normal gravity field of gravitons to cancel the effect of the two fields, one against the other. I do not, however, seriously propose this, particularly for the UFO scout ships such as saucers, spheres, ellipsoids, etc., for which available data provides strong evidence of massiveness.

For the big dirigible and cigar UFOs, which are presumably the interstellar starships, I know of no landing data or other strong direct evidence of great massiveness and the possibility remains open that these large vehicles may have an artificially reduced mass. This possible distinction between the scouts and the starships was suggested to me by Dr. James Harder. He also suggested a theoretical means for the reduction of the mass of interstellar vehicles based on the quark theory of matter. This theory is discussed in Section XIX.

C. Evidence of Solidity and Hardness

We have just provided evidence of solidity, for who ever heard of a massive object, weighing in the range of several tons, that didn't have solid surfaces? Also, it is certain that the landing gear of the UFOs in the examples cited were of harder material than the earth or crossties on which they rested. The principle that "the indenter is harder than the indent" underlies hardness testing, although it is not usually the direct basis for the laboratory testing of material hardness. The direct basis is simply the depth of the dent made by a small hard object under a prescribed loading.

Other evidence of solidity and hardness is given by the sound of bullets striking UFOs. UFOs have been shot at hundreds of times. On many occasions, the bullets have been heard to impact. On other occasions, the distinctive whine of ricochets has been heard. For brevity, only one example is given here. Another example is given in Section VII.


On May 13, 1967, at 1:45 A.M., Michael Campeadore was driving nearing St. George, Utah, when he heard a loud humming sound (Lorenzen, UFOs Over the Americas, 46). It was so unusual that he put on his brakes and jumped out of his car. It was then that he noticed a huge object, about 40 to 50 feet in diameter, hovering 25 to 35 feet above his car. Thoroughly frightened, he loaded an ammunition clip into his 0.25 caliber pistol and squeezed off point-blank shots. He heard the bullets hit and ricochet as if they had struck metal.

The ricochet of bullets in this and similar cases indicate that the UFO shell is composed of a hard material, or at least presents a hard surface, for if it did not the bullets would penetrate rather than glance off in a ricochet.


Two eleven-year-old San Diego, California, boys sneaked up on a UFO in a darkened vacant lot and rapped on it with a flashlight. They too performed a useful experiment, demonstrating solidity. Their case was one of those seriously studied by The National Enquirer UFO panel in their "best evidence short of conclusive proof" contest (UFO Investigator, February 1974). When struck with the flashlight, the UFO flared up red, began to whine, and took off—as, meanwhile, so did the boys.

D. Conclusion

We have examined, briefly, the available types of data pertaining primarily to the structural properties of the UFO. This data includes the properties of weight, mass, solidity, hardness, and density. The UFO properties in each case are not unlike the corresponding properties of Earth vehicles. The lone point on mass density placed that particular vehicle more or less in the range of a loaded rocket system, or a submarine, and heavier than a jet aircraft.

These down-to-earth physical properties—that is, the similarity of the physical properties of unconventional machines to those of Earth machines—tend to confirm that the investigation and study of the UFO by means of the physical sciences is the correct approach. The variable-geometry property of their retractable and adjustable landing gear also confirms that, structurally, here are ordinary machines as we know them. On the one hand, as machines, they seem to very much belong to our universe. On the other hand, they are unexplainable in terms of natural phenomena such as ball lightning, air plasmas, and the like, even though they show all the characteristics of being surrounded with a plasma. The latter point will be discussed in great detail in Section III.

In the following section, we briefly discuss the unconventional machine's fabulous performance.


Excerpted from UNCONVENTIONAL FLYING OBJECTS by PAUL R. HILL. Copyright © 1995 Julie M. Hill. Excerpted by permission of Hampton Roads Publishing Company, Inc..
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

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Table of Contents


Foreword by Robert M. Wood,


I. Physical Properties and Effects,

II. Performance,

III. Illumination,

IV. How Hot is UFO Radiation?,

V. Energetic Particle Ejection as Propulsion Possibility,

VI. Transmission of Forces,

VII. Direct Evidence of Force Field Propulsion,

VIII. Force Field Evaluation: Which Type?,

IX. The Saucer Hum and the Cyclic Field,

X. Propulsion Oddities,

XI. Saucer Dynamics,

XII. Silent Subsonic Operation,

XIII. Silent Supersonic Operation,

XIV. The Aerodynamic Heating of UFOs,

XV. High-Acceleration Loading On Occupants,

XVI. UFO Artifacts,

XVII. The Humanoid Occupants,

XVIII. Time Requirements for Interstellar Travel,

XIX. UFO Operational Capabilities,

XX. Summary and Conclusions,

Appendix 1. Analysis of the Sound (Hum) and Vibrations,

Appendix 2. A Comparison of Level and Ballistic Trajectories,

Appendix 3. UFO Aerodynamics: Incompressible Potential Flow Theory,

Appendix 4. Compressible Gas Dynamics With Force Field,

Appendix 5. Interstellar Travel Theory,

Appendix 6. Propulsion Equations,

Appendix 7. Analyses of UFO Fields,

Author's Technical Biography and Credentials,

Works Cited,

Index of Names and Places,

General Index,

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Sort by: Showing all of 2 Customer Reviews
  • Anonymous

    Posted August 26, 2012

    Not much here : (

    I “hope” this book is simply an intellectual exercise in trying to figure out how a hypothetical spacecraft could operate in the UFO performance envelope. However, it uses the 1974 National Enquirer UFO panel results as a reference, makes a LOT of suppositions based on second-hand evidence, and the author claims 3+ personal sightings. Sigh. At least it’s somewhat interesting although I felt a little ashamed to be reading it…generally a good indication of poor information!

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  • Anonymous

    Posted April 11, 2001

    One of UFOBC's Top 10 books of all time

    A respected NASA scientist refutes claims that UFOs are not possible by using the Scientific method to collect and analyze data from sightings. His conclusion? UFOs obey, not defy, the laws of Physics.

    Was this review helpful? Yes  No   Report this review
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