There have been persistent rumors that B-58D and E Hustler versions
were planned, but there is no evidence that such designations were
ever officially allocated by the USAF. In addition, even if there
were such designations issued, it is not at all clear what kind of
aircraft to which these designations refer.
Drawings of a Hustler
variant powered by a pair of Pratt & Whitney J58 turbojets have been
seen, but it is not certain if these represent either the B-58D
or E. There was also some thought of a Hustler version powered by four
Pratt & Whitney J75 turbojets and equipped with downward-folding
wingtips. The B-58 proposal with four Pratt & Whitney J75 engines and
downward-folding is actually the B-58MI (Model Improvement) project.
Again, it is uncertain if this aircraft is the B-58D or E,
or perhaps some other paper project. Anyone out there have more
American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday,
Post World War II Bombers, Marcelle Size Knaack, Office of Air Force
United States Military Aircraft Since 1909, Gordon Swanborough and
Peter M. Bowers, Smithsonian, 1989.
Convair B-58 Hustler: The World's First Supersonic Bomber,
Jay Miller, Aerofax, 1997.
E-mail from Vahe Demirjian on B-58MI