01641oam 2200481 450 991071286070332120200403104302.0(CKB)5470000002497575(OCoLC)1105632488(EXLCZ)99547000000249757520190625d1920 ua 0engurbn|||||||||txtrdacontentcrdamediacrrdacarrierThe problem of the helicopter /by E.P. WarnerWashington, D.C. :National Advisory Committee for Aeronautics,1920.1 online resource (18 pages, 2 unnumbered pages) illustrationsTechnical notes / National Advisory Committee for Aeronautics ;No. 4"May, 1920."No Federal Depository Library Program (FDLP) item number.Includes bibliographical reference (page 4).HelicoptersDesign and constructionHelicoptersHistoryHelicoptersDesign and constructionfastHelicoptersfastHistory.fastHelicoptersDesign and construction.HelicoptersHistory.HelicoptersDesign and construction.Helicopters.Warner Edward Pearson1894-1958,1393953United States.National Advisory Committee for Aeronautics,TRAALTRAALTRAALOCLCOGPOBOOK9910712860703321The problem of the helicopter3450643UNINA