Douglas 4-engine pre-war long-range bombers

[ACResearcher]

I'm looking for drawings and information on Douglas pre-war (basically pre-XB-31) four-engine/multi-engine bomber designs other than the B-19. There was, for instance, a DS-300 design referred to in USAAC analysis and comparisons, but no drawing to date.
Assistance is appreciated.
AlanG

 

[lark]

Perhaps a bit off topic but the 'DS' denominator was always
a bit of a mystery to me.

According to some sources ,it means - Douglas Specification
while others state that it stand for - Detail Specification.

By the way ,Rene Francillon mentions a DB-4 design offered in August 1938
to the USAAF as a replacement for the XB-19.
(Airmagazine Oct-2009)

 

[circle-5]

It also means "Design Study".