The UFO report described in this article comes from a former member of the U.S Air Force, Jimmie Lloyd, then a Lieutenant (he retired as a Lt Col). We write about this sighting because it involved a highly-trained crew of military personnel, because the UFO was allegedly spotted on radar and pictures were taken in daylight, and because this report never was recorded in the Project Blue Book records, even though it certainly should have been. It thus becomes another example of what Allen Hynek, former scientific advisor to Blue Book, often noted about the best reports being sent to some other location and bypassing the official reporting procedures. The witness contacted one of us (FC) several years ago after a radio talk-show appearance. In the fall of 1998 one of us (RH) conducted a personal interview with Lt. Col. Lloyd. 

This UFO event occurred sometime in the fall or winter of 1956. A U.S. Convair Air Force RB-36H (Peacemaker) airplane (1) of the 718th Squadron, 28th Strategic Reconnaissance Wing, based at Ellsworth AFB, Rapid City, South Dakota, had taken off before noon with a nominal crew of 22 men (17 regular flight crew and a five-man relief crew). The commander was Lt. C. Lenny Marquis. Their mission was training in the use of various air-to-ground camera and other military surveillance equipment. At the time of this sighting, America was finally getting over the aftermath of the Korean War while facing a growing Cold War with the Soviet Union. The mission of the crew was critical in this effort. 

The Air Force's Strategic Air Command operated 10 wings of B-36 bombers at this time, with about 30 aircraft in each one. Type RB-36H was the photo reconnaissance version of the B-36H. As the photos accompanying this article show, this was a huge aircraft powered by six 28- cylinder Pratt & Whitney R-4360 piston-pusher engines mounted on the trailing edge of each wing, and two pairs of J-47-GE- 19 turbojet engines mounted outboard of them. 

The huge, 10-engine heavy bomber climbed to about 40,000 feet in clear air. The time was shortly after noon. Figure 1 shows this huge bomber in flight (nicknamed "the Aluminum Cloud") as seen from below with its 230-foot wing span. 

According to the main eyewitness, Lloyd, the airplane 

was cruising in straight and level flight near its top speed of 423 mph at cruise altitude. Its six retractable and remotely controlled gun turrets (2) were in the stowed position. Details of its huge, high-resolution camera are found elsewhere. (3) Suddenly the left scanner (observer) in the aft compartment saw a metallic disc about 100 feet in diameter fly toward the airplane from the left-hand side and take up a fixed position off the left wing less than 300 feet away. (4) He reported it over the intercom system and soon the visitor's arrival was known by everyone on board. Many men rushed to the nearest porthole on the left side of the fuselage and began taking 35mrn photographs of the disc using their standard- issue cameras. (5) 

The length-to-height ratio of the UFO was about 8:1, and a low dome, about one-third the length of the object, was located at the center of the top surface, which was only 

slightly curved. The dome had three round openings or light sources approximately as shown in Figure 4. Its surface was perfectly smooth and was without seams, markings, any visible means of propulsion or other aerodynamic details. The object seemed to have an almost flat or slightly concave bottom surface. Its vertical sides were populated by many separate round sources of light, each of a different color. Their spacing was approximately as shown in Figure 4. The surface of both the main body and raised dome appeared a "light golden" hue. 

After five to eight minutes, the UFO suddenly accelerated horizontally in parallel with the B-36 and then rose at about 30 degrees above the local horizontal without pitching up or down. (The duration of the UFO's visible acceleration lasted approximately one to two seconds at the most.) All of the peripheral bluish lights became much brighter and definitely greenish as the object accelerated out of sight in several seconds. It did not appear to rotate about its vertical axis nor did it appear to wobble or undulate in flight. In addition, no buffeting or unusual noises were felt or heard by Lloyd during this sighting. Flying at nearly 423 mph, the UFO and airplane would have traveled a distance of about 55 miles during this eight-minute period. 

Lloyd was serving as a substitute navigator in the nose of the aircraft during this flight. He recalled that they were somewhere in northern South Dakota and probably near the North Dakota state line during the sighting. At this time he held five specialty ratings (primary, photographic, radar, weather, and electronic countermeasures). 

The radio operator used a preassigned frequency on his single sideband radio to contact ground authorities about the UFO while the sighting was ongoing. Lloyd told us that ground radar was able to detect the UFO as well as the airplane. 

Later he wrote an account and stated, "When we got on the ground, we had to turn in all of our logs, equipment, photographs, everything, to an intelligence unit called 'Reci Tech' [Reconnaissance Technology] which was the central processing unit for the whole wing. We were debriefed by Intel officers, reminded that we all held top-secret clearances, and that we couldn't reveal any of this information for a period of 12 years. Then, several weeks later, we were debriefed again by some officers from higher headquarters who reminded us also of the same 12-year period, and in fact, when I was discharged back in 1960 from the active Air Force into the active reserves, I was also reminded again of the 12-year period to not reveal any of this information." 

It is clear that Air Force officials wanted to keep this sighting completely under wraps. And in this they were successful, since this report cannot be found in Project Blue Book files, the UFOCAT database of CUFOS, or those of Larry Hatch or Dominique Weinstein. 

DISCUSSION

This rather typical high-altitude close encounter by a military airplane involved a single, three-dimensional, symmetrical aerial object that was "witnessed and photographed by many highly qualified airmen and officers. It is instructive to apply our knowledge of terrestrial aircraft design to this object to try to better understand its most likely physical characteristics, We begin with its weight. 

Airframe weight. Terrestrial aircraft typically employ a standardized construction involving smooth sheet metal attached to ribs and longitudinal spars (generally referred to as a "monocoque" construction). This particular construction design yields an almost linear relationship between an aircraft's total "wetted" or outer surface area and its structural weight (with no engines, fuel tanks, interior fittings, or cargo included). (6) 

An approximate surface area of 15,000 sq. ft. approximates the present UFO. This results in an estimated air frame weight of about 110,000 pounds if its construction is similar to an aircraft. Without knowing its interior components, of course, it isn't possible to estimate its gross weight. If gross weight were known, one could better estimate the total horsepower required to propel the object at 423 mph. As a comparison, the gross weight of the RB-36H was 357,500 pounds. 

Wake turbulence. When aircraft, whether conventional or disc-shaped, travel through the air they typically produce invisible air turbulence behind them. Vortex zones initially spread out one to two seconds after leaving a wing's edge and tip. For the next two to three seconds the vortex effect remains together (i.e., retains its compactness), but loses 60-80% of its capacity to roll another aircraft passing through it. A downwash effect persists, however. It also maintains an almost constant volume (see the parallel lines behind the UFO in Figure 5). After about five or six seconds, the turbulent area begins to break apart into separate cross-trail pillows. At a point some three to five minutes behind the object there is almost no coherent rolling moment remaining. (7) their useful information on wake vortices is found elsewhere. (8) It can also be shown that if this UFO were moving through the local airmass with zero pitch angle, i.e., with zero angle of attack, no wake vortex should be formed behind it. This is indeed supported by the fact that no air turbulence was recalled by Lloyd onboard the aircraft. 

The white condensation trails sometimes seen behind jet aircraft flying at high altitudes are produced by rapid heating of moist air from the heated engine exhaust. These contrails provide useful insights about the highly unstable zones behind an aircraft, so it would be educational to view the photographs that were taken to see if condensation trails were present. (Of course, it would be just as important to obtain characteristics of the UFO from the photo.) 

Furthermore, the fact that the UFO was able to fly much faster than the RB-36H and climbed without changing pitch angle suggests some type of gyroscopic attitude-stabilization system. 
 
 

Strouhal shedding number. This dimensionless number (S) represents "aperiodic" air flowing alternately over the top and then the bottom surface of a symmetrical solid while it travels through the air. In essence, S represents an unsteady shedding of a Von Karman vortex street (a stream of air). (9) For aircraft with a high Reynolds (10) number, S is approximately 0.21 (used here). The present UFO was approximated by a 12.5-foot diameter cylinder with its longitudinal dimension moving perpendicular to the direction of travel. Thus: 

According to this calculation, one would expect a vortex street flowing, alternately, first over the upper surface and then the lower surface of the UFO approximately 10 times a second. Whether this effect could result in some kind of visible phenomenon or an audible noise remains to be seen. However, UFO investigators are urged to seek such data in other such cases. 

Aerodynamic drag and structural considerations.
The total frontal area relative to the local air mass of a 100- foot diameter disk having the cross-sectional shape shown in Figure 5 would be about 1,250 square feet at zero pitch angle (i.e., minimal silhouette). Of course, drag would increase, relative to the air mass, if its angle of attack increased. 

If the UFO was constructed using a terrestrial-based monocoque construction it would undergo various bending moments as a function of g loading (constant earth gravitation effect plus accelerative forces) during turning. On the other hand, if the means of propulsion of the UFO incorporated a mechanism where each micro-element (perhaps at the molecular level) is integrally involved in propulsion and properly coordinated in the same vector and acceleration level, then the UFO's entire body would act as a single point mass. The implications of moving a point mass simplify some of the consequences while making others more complex. 

The paucity of data in this case prevents us from saying much more about the possible physical characteristics of this UFO. Interested readers are urged to write to us in care of CUFOS. 

REFERENCES

1. "Convair B-36" description in air-recon.com Encyclopedia, Aerospace Publishing, Ltd., 1997-2000 (194.205.16. 17/ency/B/B-36.asp); and "Convair RB-36H 'Peacemaker,"' in USAF Museum, Wright-Patterson AFB, Archives Gallery; Leonard Bridgman, ed., Jane's All the World's Aircraft (London: Jane's Publishing, 1957- 1958); Wayne Wachsmuth, B-36 Peacemaker in Detail and Scale (Carrollton, Tex.: Squadron/Signal, 1997). 

2. Each turret had twin 20-mm cannons. Two more 20-mm cannons were mounted in the nose and two more in the radar-controlled tail turret This reconnaissance version of the B-36 with guns was referred to as 'Tetherweight II." 

3. "RB-36 Reconnaissance Camera;" in USAF Museum, Wright-Patterson AFB, Cold War History Gallery. 

4. The witness said later (October 5, 1998, to author RH) that "the entire object would have been covered by my closed fist held and viewed at arm's length." This would make the UFO subtend an angle from the nose of the airplane of almost 10 degrees of arc. A 100-foot-long object subtending 10 degrees of arc would lie 567 feet from the observer, close enough to the witness's estimate. 

5. Haine 35mm format cameras were used. Everyone also had a pair of binoculars and a standard UFO reporting form developed for Project Blue Book. 

6. Brian E. Smith, NASA Ames Research Center, personal communication, April 12, 2000. 

7. Vernon J. Rossow, NASA Ames Research Center, personal communication, October 10, 1998. 

8. John H. Olsen, Amold Goldberg, and Milton Rogers, eds., Aircraft Wake Turbulence and Its Detection (New York: Plenum, 1971). 

9. James W. Daily, and Donald R. F. Harlman, Fluid Dynamics (Reading, Mass.: Addison-Wesley, 1966), p. 381. 

10. The dimensionless Reynolds number is important in analyzing any type of flow where there is shear. It is defined for a vehicle moving through a fluid medium as scale velocity times scale length divided by kinematic viscosity. A critical velocity range above which a fluid flow becomes turbulent, below which it remains viscous, and in which it may be either, depends on several factors, including temperature. 

Source: CUFOS IUR (International UFO Reporter), Spring 2000, Volume 25, Number 1.