Martin B-10B bombers.<ref>[https://books.google.com/books?id=OsIBdVV_YOAC&pg=PA43&lpg=PA43&dq=Goodyear+blimp+%22tangier+island%22+1936&source=bl&ots=0JGEvff5Ch&sig=9PIYsKEnhr0p-PCGWitjvKicBAU&hl=en&sa=X&ved=0ahUKEwjnq6-q3s_WAhVrw1QKHWxMCbIQ6AEIQjAJ#v=onepage&q=Goodyear%20blimp%20%22tangier%20island%22%201936&f=false Bentley, Stewart W., Jr., PhD., "The Touch of Greatness: Colonel William C. Bentley, Jr., USAAC/USAF; Aviation Pioneer], Bloomington, Indiana: AuthorHouse, 2010, , pp. 41–42.</ref> Variants LB-13 Seven aircraft ordered but delivered as the Y1B-4 and Y1B-6 with different engine installations. Y1B-6 Two pre-production aircraft and three converted B-3As, as the LB-10 but with two Wright R-1820-1 engines. B-6A Production version of the Y1B-6, 39 built. Operators United States Army Air Corps Specifications (B-6A) See also References Notes Bibliography Wagner, Ray. American Combat Planes''. New York: Doubleday, 1982. . External links USAF Museum article on B-6 USAF Museum article on LB-13 Keystone B-06 B-6 Biplanes Twin piston-engined tractor aircraft