Boeing Monomail

Henry R.Palmer This was Air Travel Bonanza Books 1967

Two prototypes were built, an all-cargo version and a combination passenger and cargo version, with a total load capacity of about 1500 lbs. The plane was hampered by technology, it really needed a more powerful engine and variable pitch propeller to achieve its full potential (remember, this was only 27 years after the Wright brothers first powered flight).
None remain, both were lost in crashes in 1935, one in Wyoming, one in Colorado.

Aviation Yearbook February 1942, McGraw-Hill