Permalink: http://www.boeingimages.com/archive/Vintage-United-Air-Lines-Model-221-Monomail-2F3XC5FVQ7Z.htmlCopyright © Boeing. All Rights Reserved.View Photo/Video onlyConceptually similarBoeing Monomail on ApronModel 221A MonomailModel 221A Monomail Loading PassengersModel 221A Monomail Passenger Cabin, Looking AftModel 221 MonomailMonomail on Tarmac221A Monomail at Boeing Field HangarBoeing Monomail CockpitModel 200 Monomail in FlightView AllView more with similar tones Vintage United Air Lines Model 221 MonomailBuy A Print or License This PhotoWhat Type of Order?Usage:The Boeing Monomail, designed initially to carry cargo and mail, was one of the most revolutionary airplanes in commercial aviation history. Two were built: the Model 200 mail plane and the Model 221 six-passenger transport. Both subsequently were revised for transcontinental passenger service and became Model 221As. The Monomail achieved major performance increases not by the addition of brute horsepower, but by structural and aerodynamic refinements. Air resistance was reduced by the Monomail's smooth, all-metal construction; cantilevered (that is, without struts), low-wing design; and the anti-drag cowling over the air-cooled Hornet engine. Retracting the wheels into the wing during flight further improved the mail plane's aerodynamics.BI210532 (5006b)Maximum size:6000px × 4800px (~82 MB)20.0in × 16.0in (300dpi)License type:Rights ManagedKeywords:1930s-airplanes-Boeing livery-commercial-commercial airline livery-commercial passenger planes-day-exteriors-full body views-glare-ground shots-historic production status-mail planes-Monomail-Monomail Model 221A-monoplanes-photos-propeller planes-right side views-shadows-sunshine-tarmac-text-unpainted-vintage / retroRelated Photo/Videos:View AllRelated Virtual folders:Monomail 221