North American XB-25E Mitchell

Last revised April 1, 2007

The XB-25E was a standard production B-25C-10 (serial number 42-32281) modified for anti-icing research. The carburetor air intake duct was faired internally into the top of the cowling and an anti-icing air intake was mounted at the bottom. Each row of cylinders exhausted through a separate exchanger, one ported outboard and one inboard of each nacelle. Ram air from the lower cowling duct was routed underneath the engine to a split duct, each side of which was directed to one of the heat exchangers. Air admitted to these heat exchangers was directed through a series of gates that allowed diversion of heated air either to the anti-icing system or out the exhaust. A complex system of ducting led the hot air to the outer wing leading edges and also into the fuselage and to the leading edges of the tail. It was intended that the temperature of the hot air would be sufficiently high that ice on the wing leading edge surfaces would be vaporized rather than melted, which would have prevented water from flowing aft and then freezing again on flaps and ailerons.

The airplane was completed early in 1944 and first flown on February 4 by test pilot Joe Barton. The plane carried the name "Flaming Mamie", chosen because of the tendency for an engine to catch fire when it was started. The heated wing system did do an effective job of de-icing, but it proved to be very costly and was not adopted for production. Conventional de-icing boots continued in general use.

The plane was deliberately crashed, along with a lot of other planes, in a program to develop fire extinguishing systems for aircraft.


  1. B-25 Mitchell: The Magnificent Medium, N. L. Avery, Phalanx, 1992.

  2. Medium with the Mostest--The B-25 Mitchell, Jerry Scutts, Air International, Vol. 44, Nos 2 and 3, 1993.

  3. Boston, Mitchell, and Liberator in Australian Service, Stewart Wilson, Aerospace Publications, 1992.

  4. Famous Bombers of the Second World War, William Green, Doubleday, 1959.

  5. North American's Flying Gun--The Story of the B-25 From Paper Airplane to Legendary Bomber, Jack Dean, Wings, Vol 23 No 4, 1993.

  6. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.

  7. North American B-25A-G Mitchell, Aircraft in Profile, Doubleday, 1966.

  8. Jane's American Fighting Aircraft of the 20th Century, Michael J. H. Taylor.

  9. E-mail from Bill Wynne on fate of XB-25E.