http://www.aerofiles.com/_h.htmlHelicopter Aeroplane 1920 = OB; v: 150. Had ordinary tractor prop, plus a horizontal prop in a cut-out of the upper wing, which would allow near-vertical descent. Claimed climb to 18,000' in 10 minutes.
Helicopter Aeroplane c.1932 = OhwM. A realization of the 1920 design, possibly a rebuilt Crawford A-1 Parasol, since its registration [X12205] earlier belonged to such a machine. The horizontal prop was driven by a separate engine, mounted in the wing. The added weight of this engine made the airplane too heavy, and cooling was blocked by the fuselage—it probably never flew.
And Chris Matthews of San Pedro, California. See http://www.google.ca/patents/US1307826 for a slightly earlier variation on the Hall-Matthews theme.hesham said:I get a full name to the designers,Charles S. Hall from Hall Aeroplane Company,and C.
Matthews,it was mentioned in Aerofiles in two projects,one of 1920 and 1932; ...