In a period in American aviation history when the biplane configuration was dominate, there was a slight aberration when the parasol became popular.
From the start of the Depression until the mid-1930s, there was a strong spurt of interest that saw about 30 parasol designs certificated for production. With their wings placed above the fuselage, these planes were certainly distinctive compared to the popular biplanes of the time.
Though there had been earlier parasol aircraft, they were not much in favor until the successful Lockheed Air Express (pictured above) stimulated a revival of the configuration in 1929. A variant of the Lockheed Vega, the Air Express moved the pilot behind the passenger compartment to allow more room in the cabin. The parasol wing was needed so the pilot could have better visibility from the rear of the fuselage.
Although designed as a mail/passenger aircraft, the craft was famous for its many record-breaking flights. The popularity of the Air Express may have fostered the interest in the parasol configuration as evident in the appearance of the Doyle, Davis, Timm and others. The most popular of the parasols was the Fairchild Model 22, certified in April 1933, the end of the design’s heyday.
The actual reason for the surge of popularity of the parasol configuration over the short period of four years remains a mystery. There were some definite aerodynamic advantages to the design. With their high-wing position, parasol aircraft tended to be very stable compared to other configurations. Also, with one less wing there was considerably less drag than with a biplane, allowing higher speeds with the same engine.
One writer at the time speculated that the parasol offered the advantage of being a cheaper machine to build because only one wing had to be constructed. However an examination of the 1930-31 “Directory of Approved American Airplanes” published by Western Flyer showed that, contrary to that assumption, parasol aircraft were more expensive than biplanes with the same powerplants. For example, the Inland Sport parasol with a Warner 110-hp Warner Scarab sold for $4,580 while the Waco RNF with the same engine sold for $4,250. Equipped with a Kinner K-5 100-hp engine the Timm Collegiate parasol sold for $4,985, while an American Eagle with the same engine went for $3,385.
There was some performance advantage demonstrated with one wing on the parasol as a Kinner K-5-powered Davis listed a top speed of 127 mph, while biplanes with the same engine posted speeds of 106 to 115 mph. Though the parasol advantages were not enough to make the type popular, the parasol configuration offered great downward visibility and better stability, making for a viable flight training machine.
LOCKHEED AIR EXPRESS
The cigar-shaped Lockheed Air Express was popular from the very beginning. The name alone implied high-speed, efficient transport. Its cantilever parasol design was novel enough to garner notice. Designed by Jack Northrop, the Air Express was a departure from the familiar Vega form, which shared the same basic fuselage shape. Lockheed was able to use the same fuselage in three different locations; with the Vega being high-wing, the Sirius low-wing, and the Air Express a parasol location.
Although the Air Express was expressly designed for Western Air Express as a combination mail and passenger ship, only one was acquired by the airline. Its performance proved to be exceptional and was used for many record-breaking flights across the United States. The design first came to national fame when Frank Hawks in “Texaco No. 5” broke the transcontinental speed record held by a Lockheed Vega with a time of just over 18 hours.
FOKKER F-14 PARASOL
The biggest of the high-wing designs was the large passenger-cargo transport of Fokker. Like the Air Express it was designed from ideas presented by Western Air Express. Apparently the Western Air Express pilots still believed they had to be outside, separated from their passengers, in an open cockpit behind the cabin. The F-14 could either be used as a cargo-transport capable of hauling 1,600 lbs. of payload, or as a transport able to carry six passengers with room for a load of mail. Indeed, it was a large machine with a gross weight of 7,200 lbs., compared to that of the Air Express, which was 4,375 lbs. About a dozen were built, including some for the U.S. Army.
FAIRCHILD MODEL 22
The light-weight, sporty Fairchild Model 22 and its many variations was the most successful of the parasol designs. The Model 22 was introduced in 1931 as a sport flyer and flight training plane, maybe to fill the gap between the heavier classical biplanes (Waco and Travel Air) and the newer light monoplanes using the new 36- to 65-hp engines. With its open cockpit and the pilot in the aft cockpit, and the passenger under the wing, it served as a great transition from the standard biplanes.
The Model 22s utilized most of the standard air-cooled four-cylinder in-line engines available at the time, including the Menasco, Cirrus, Wright-Gypsy and Michigan Rover. The later models were fashioned to make use of the Warner Scarab and radial engines. The planes were in regular production from 1931 through 1935, with more than 150 produced.
The parasol had its heyday, briefly, for a few years. Even if only limited numbers were built, the number of designs was relatively plentiful.
Dennis Parks is Curator Emeritus of Seattle’s Museum of Flight. He can be reached at email@example.com.