In the HM.14 Pou du Ciel, Frenchman Henri Mignet attempted to design an airplane that almost anyone could build and fly safely. He sought to give everyone access to the skies at a time when flying was the exclusive province of professional pilots. Pou du Ciel ('poo-do-say,' literally "Sky Louse" but the English coined the term "Flying Flea") is an appropriate name for this small, unusual aircraft. The novelty of the HM.14, along with Mignet's effective marketing, compelled hundreds of people to build and fly the Pou du Ciel in France and Britain during the 1930s.
Henri Mignet was born in France in 1893. He had the gift of understanding machines and technology and pursued a career in electricity. He became interested in aviation as a teenager and by age eighteen, he was corresponding with Gustav Lilienthal (brother to Otto, the famous German glider pioneer) about building aircraft. After World War I, Mignet began to experiment with powered aircraft. His first designs barely flew but in 1927 he built the HM.8, his first design capable of sustained flight.
During the 1920s, the idea of constructing a homebuilt aircraft from published plans was popular in the United States but in Europe, the idea was unknown. In Britain and France, the established manufacturers dominated the production of powered aircraft. Mignet decided to publicize the HM. 8 in the French magazine "Les Ailes." Interest in this aircraft began to grow, encouraging Mignet to write another article that appeared in "Le Sport de l'Air" in 1931.
To make the airplane as simple to build and fly as possible, Mignet employed some unorthodox design elements in his next major design, the HM.14. He decided this airplane could fly without ailerons, elevator, and rudder pedals, and that he would use two main wings. He mounted one on struts above the fuselage and ahead of the pilot. To control pitch, the pilot pivoted this wing by moving a control stick fore and aft. Mignet mounted a second wing firmly fixed to the top of the fuselage behind the pilot. To turn, the pilot moved a rudder surface by swinging the control stick left or right. A generous amount of dihedral built into both wings caused the airplane to automatically bank when turning. Mignet claimed that any man who could nail shut a wooden crate could build his own HM. 14.
The French press began to refer to the new aircraft as the "Pou du Ciel," and the name stuck. After publishing a book in November 1934 that described in detail how to build this airplane, public interest skyrocketed. By March 1935, 500 HM.14s were under construction in France. In August, Mignet flew his HM.14 to Britain and soon gained widespread attention. Construction began on hundreds of HM.14 airplanes and builder/pilots received permits to fly more than 80. The Flea's performance appealed to many; the maximum speed of the average Flea was between 80 and 105 km/h (50-65 mph), depending on the engine, the flying weight, and the quality of construction. A pilot could fly from 80 to 161 km (50-100 miles) before needing to refuel and she could usually take off in less than about 180 m or 600 ft.
During the same month that Mignet introduced the "Pou du Ciel" to Great Britain, the first fatal crash of a Flying Flea happened in Algeria. In April 1936 the first British fatality occurred. The authorities saw pilot incompetence as a leading factor in the crashes until May 1936 when Royal Air Force Squadron Leader C.R. Davidson died. Government officials in both France and Britain banned flights and subjected the HM.14 to wind tunnel tests. The results showed that under certain flight conditions, the pilot could not recover from a dive. Based on their findings, Mignet soon modified the design and solved most of the problems but the bubble of public infatuation with the Flea had burst. He continued his efforts to produce new aircraft and built a factory in the United States to make parts, but Mignet never recaptured the initial public interest first shown the HM.14.
In 1935 when the Flea was near the peak of its popularity, an American entrepreneur and the president of the Crosley Radio Corporation, Powel Crosley, Junior, obtained a copy of Mignet's book "Le Sport de l'Air." The airplane immediately appealed to Crosley and he ordered his personal pilot, Edward Nirmaier, to build one. With the help of Dan Boedeker and Herb Junkin, Nirmaier began construction on October 1, 1935. Funded by Crosley, he used materials readily available near the airport at Sharonville, Ohio. He even scrounged an ABC Scorpion engine. Nirmaier made the first test flight exactly one month later on November 1. This became the first HM.14 built in the United States. Nirmaier had adhered closely to Mignet's plans in constructing the aircraft, deviating only in the methods used to weld several parts. Powel's daughter, Page, christened the plane La Cucaracha (The Cockroach) using a bottle containing water from the Atlantic Ocean near Kitty Hawk, North Carolina. This was the site of the first successful flight of a powered, heavier-than-air flying machine, the 1903 Wright Flyer (see NASM collection). The U. S. Bureau of Air Commerce licensed the airplane as the experimental Crosley Flea.
Crosley never intended to produce the HM.14, but he was happy to promote it as the aircraft for the common man. In December 1935 Nirmaier took the Crosley Flea to the 8th annual All American Air Maneuvers airshow in Miami to show the airplane off. It flew well, but on the first day, a gust of wind flipped it over while taxiing. Nirmaier quickly repaired the damage and took the aircraft aloft for a short flight two days later. This became the Crosley Flea's last flight. Meet organizers awarded the HM.14 a trophy (see NASM collection) for efficient construction and operation, but the aircraft remained grounded for good.
Crosley's Flea remained stored in a hangar until 1939 when a fire forced workers to hastily move the airplane. They saved the Flea and placed the small aircraft in a barn owned by insurance adjuster Walter Paner. It remained there until 1957 when vintage aircraft enthusiast Patrick Packard tracked it down. He purchased the Flea minus its wheels and engine but Pat located Ed Nirmaier and reclaimed the original wheels that Nirmaier had installed on his lawnmower. Pat donated the aircraft to the Smithsonian in about 1960. In 1991 the Experimental Aircraft Association Museum in Oshkosh, Wisconsin, borrowed the Flea and Pat Packard and Patti Koppa undertook a full restoration. Pat reproduced an accurate wooden replica of the missing, original ABC Scorpion engine.
Wingspan: 5.8 m (19 ft)
Length: 4.1 m (13 ft 6 in)
Height: 1.7 m (5 ft 6 in)
Weight: 158 kg (350 lb)
Engine: ABC Scorpion air-cooled, two-cylinder, 39 horsepower
Designer: Henri Mignet
Builder: Edward Nirmaier
References and Suggested Reading:
Britain's Flea Craze webpage at http://au.geocities.com/ozflea29/index.html.
Mignet HM.14 Pou du Ciel "Crosley Flea" Curatorial File, Aeronautics Division, National Air and Space Museum.
Ellis, Ken & Geoff Jones "Henri Mignet and his Flying Fleas," Haynes Publications Inc., Newbury Park, California, 1990.
Crosley Flea span and length from "Cincinnati Times Star," 30 November 1935.
Christopher Moore, Russ Lee, 9-3-04
