China Clipper (NC14716) was the first of three Martin M-130 four-engine flying boats built for Pan American Airways and was used to inaugurate the first commercial transpacific airmail service from San Francisco to Manila in November 1935. (Wikipedia)
China Clipper over the construction of the Golden Gate bridge 
China Clipper in Hawaii
A Pan Am “China Clipper” soars over an old Chinese junk near Hong Kong Harbor, 1937.
A cutaway diagram of the China Clipper
The China Clipper could cruise 3200 miles at 130 mph, and carried up to 32 passengers