Winnie Mae

Definition: The name of the record-setting Lockheed Vega airplane that was flown by Wiley Post from 1930 to 1935.
Significance: Piloted by Post, the Winnie Mae, the most aerodynamically advanced aircraft of its time, made two record breaking around-the-world flights and pioneered stratospheric flight. The Winnie Mae now resides in the National Air and Space Museum in Washington, D.C.
In 1928, Oklahoma oilman F. C. Hall bought a Vega airplane from Lockheed Aircraft Company so that his company pilot, one-eyed Wiley Post, could fly him to important business meetings. Hall named the plane after his daughter, Winnie Mae. When the stock market crashed in 1929, Hall sold the plane back to Lockheed and had them remove the name from the aircraft, but just the next year, in June, 1930, he decided he needed another Vega, which he also named Winnie Mae. It was this Winnie Mae that Wiley Post used to make all his famous flights, thereby making it one of the best known of all aircraft.
The Lockheed Vega was a beautifully streamlined high-wing aircraft, with an internally supported wing and tail, in an era when other aircraft were enormously draggy biplanes or at least had exposed wing struts and wires and draggy landing gear. The Vega fuselage was built by first gluing together very smooth shell halves of laminated plywood that had been shaped in a concrete mold; the fuselage thereby gained most of its structural strength from its outer skin, known as a semi-monocoque construction. The efficient, fabric-covered wood wing used an 18 percent thick Clark Y airfoil at its root, tapering to 9.5 percent thickness at the wingtip. Both Winnie Mae Vegas were delivered with 9-cylinder, 420-horsepower Pratt & Whitney Wasp radial engines.
As delivered, the first seven-place Vegas had wing-spans of 41 feet, an empty weight of 2,361 pounds and a useful load of 1,672 pounds. The early Vegas cruised at about 140 miles per hour and, under sea level conditions,climbed at 1,300 feet per minute and landed at 54 miles per hour. Their 96 gallons of fuel and 10 gallons of oil gave a range of 725 miles.
The Hall’s second Lockheed Vega 5B cost him $22,000. Already interested in flights that furthered aviation developments, he agreed to let Post prepare the new Winnie Mae for the Los Angeles-to-Chicago race in August that was part of the 1930 National Air Races. Additional fuel tanks were added in the passenger compartment, bringing capacity to 500 gallons, the oil capacity was increased to 25 gallons, and a high-ratio supercharger was fitted that brought the horsepower up to 500 for takeoff. The incidence angle of the wing was decreased to lower fuselage drag and increase the cruising speed by about 10 miles per hour, but this modification also increased the landing speed to about 80 miles per hour. Despite the loss of his magnetic compass, which cost him an extra 40 minutes, Post still won the first place prize of $7,500 by averaging 192 miles per hour over the 1,760-mile course. (Art Goebel, flying the first Winnie Mae,was second.)
By early 1931, Post had decided that he wished to demonstrate the advances in aviation by flying around the world, and Hall was willing to provide the necessary financial backing. Realizing that navigation would be critical, Post enlisted as a second crew member the navigation expert Harold Gatty, who had helped him prepare for the Los Angeles to Chicago race. Post, profiting from Jimmy Doolittle’s pioneering flights with “blind flying” instruments, installed rate-of-climb and gyroscopic instruments, a turn-and-bank indicator and an artificial horizon, in a cluster that made it easy to scan them while flying in clouds, realizing that the ability to fly solely by reference to instruments would be critical to their survival as well as their success.
A favorable “weather window” finally came on June 23, 1931, and Post and Gatty took off from New York for the nearly seven-hour flight to Harbour Grace, Newfoundland, then the sixteen-hour transatlantic flight to England, followed by stops in Germany, Russia, Siberia, Alaska, Canada, and Cleveland. Finally they were back at Roosevelt Field in New York, to be met by a crowd ten thousand strong. A ticker-tape parade, a visit with President Herbert Hoover in Washington, D.C., gala celebrations in Oklahoma, and a tour of the country followed.
Post and Gatty’s official flight time was 8 days, 15 hours, and 51 minutes. They had eclipsed the flight times of the previous three around-the-world flights (two U.S. Army Douglas World Cruisers in 1924 and the Graf Zeppelin in 1929). The Winnie Mae had performed faultlessly,proving the thoroughness of Post’s preparation, the aerodynamic efficiency of the Vega, the necessity for blind flying instruments, and the reliability of the Pratt & Whitney Wasp engine.
Wiley Post and the Winnie Mae were not through yet. Post decided that he could take advantage of emerging technological advances—an air-driven autopilot, a radio compass that would point toward any transmitting radio station, and an adjustable-pitch propeller that he could optimize for takeoff or cruise—to make a solo flight around the world. A little over a year later, on July 15, 1933, Post and the Winnie Mae lifted off from Floyd Bennett Field in New York (now JFK International Airport). Berlin, Germany, was his first stop, establishing yet another transatlantic record. Fuel stops were made in Russia, Siberia, Alaska, Canada, and then it was nonstop to New York. Post and the Winnie Mae had broken the previous year’s record by more than 21 hours, becoming the first person and the first airplane to fly around the world twice, and the first to do it solo.
Another ticker-tape parade down Broadway, another presidential visit, major aviation awards, and joint appearances with the Winnie Mae in Rockefeller Center in New York and in other cities followed. Post realized, however, that further advances in around-the-world flight required the ability to fly above the weather and he began to plan for Winnie Mae’s last great adventure: stratospheric flight (about 36,000 feet above Earth’s surface, where the air temperature becomes constant).
Winnie Mae received an external supercharger that compressed the air before it reached the carburetor, augmenting the internal supercharger (boosted to a 13:1 compression ratio) which compressed the fuel-air mixture after the carburetor, allowing Winnie Mae’s Wasp engine to develop its rated power of 450 horsepower at 35,000 feet and have the ability to climb as high as 50,000 feet. The airplane’s ignition magnetos had to be pressurized to prevent sparking between high voltage sections in the thin air. The landing gear was replaced with droppable gear and the airplane was designed to be landed on a belly skid. Post also expended a great deal of effort developing a completely enclosed pressure suit for himself, finally achieving a suit that included pure oxygen from a liquid oxygen container while still allowing him to fly the airplane. By late 1934, Post had reached an unofficial 50,000-foot altitude and had confirmed the existence of the jet stream by measuring 200-mile-per-hour winds there. In March, 1935, his quest for a nonstop, high-altitude, transcontinental flight brought him and the Winnie Mae one hundred miles past Cleveland before his oxygen supply was exhausted; he had experienced 100-mile-per-hour tail winds. An engine failure on the fourth attempt, in June, convinced Post that the Winnie Mae and her original engine were getting tired, and he agreed to sell her to the Smithsonian Institution for $25,000.