'Donuts-on-a-Rope' Contrail Suggests Flight of Classified
Aircraft
Aviation Week & Space Technology
04/26/2004, page 29
William B. Scott
Colorado Springs
'Donuts-on-a rope' contrail suggests flight of classified
aircraft
'Pulser' Back?
After a long absence, what may be a classified aircraft powered by
an impulse-type engine appears to be back in the air again. Its
distinctive "donuts-on-a-rope" contrail was spotted recently above
Utah's Wasatch Mountains.
More than a decade ago, cotton-ball-like contrails were spotted and
photographed periodically by observers throughout the U.S., but
reports had dropped off sharply in recent years (AW&ST May 11,
1992, p. 62). The latest sighting over Utah on Mar. 21 was of
particular interest, though, because the unknown "pulser"
apparently was shadowed by another, conventionally powered chase
aircraft that left a smooth, unbroken contrail. The two
contrails--one smooth, the other a string of puffs--remained
parallel across at least 120 deg. of sky, indicative of distinctly
different powerplants.
The two contrails were spotted just before 3 p.m. MST by Phidias
Cinaglia, a mechanical engineer who lives in the mountains east of
Salt Lake City. He did not see or hear the two aircraft fly
overhead. However, he noticed the contrails very soon thereafter,
because they were still well defined. Initially, he saw distinct
side-by-side puffs, suggesting a twin-engine aircraft with
powerplants firing simultaneously. Cinaglia remarked that each of
the impulse contrails was "an unbroken string of pearls" across a
large arc of the sky.
In the 2-3 min. required to run into his house and grab a camera,
the side-by-side puffs had merged, and the contrails were rapidly
dissipating (see photos). Nonetheless, his photos show clear
differences between contrails of the two aircraft.
Cinaglia's home is at 8,000-ft. elevation, and the clear mountain
air and afternoon Sun angle enabled an exceptionally clear view of
the pulser's contrail structure. He said distinct, horizontally
separated puffs were clearly visible initially, and each puff
displayed well-defined "residual vortex" patterns. He suggested
that "whoever designed the engine control system did an excellent
job," because both powerplants were firing at exactly the same
time.
