Coanda’s Claim
The story of a jet flight in 1910, just seven years after Kitty Hawk, may be too good to be true.
- By Frank H. Winter
- AirSpaceMag.com, December 06, 2010
A replica of Coanda's 1910 Propulseur is on display at the National Military Museum in Bucharest, Romania.
Massimo Foti
The weird-looking flying machine was called “Turbo-Propulseur” by its inventor, the brilliant Romanian aeronautical engineer Henri Coanda. A hundred years ago this week, on December 10, 1910, the Propulseur accidentally flew—or so Coanda would later claim—during taxiing tests at Issy-les-Moulineaux, outside Paris. If true, it was the world’s first jet flight. But Coanda’s accounts of the alleged flight changed markedly over the years, and a close examination of his stories, as well as his patent documents, leave more than a little doubt that it happened at all.
The Propulseur caused a sensation when it was exhibited at the Second International Exposition of Aerial Locomotion, held at the Grand Palais in Paris from October 15 to November 2, 1910. Coanda’s invention was strikingly different from the usual flimsy biplanes of the day. Instead of a propeller, the revolutionary monoplane had an inverted flower pot-shaped front, with built-in rotary blades arranged in a swirl pattern. The heart of the machine was an internal turbine screw driven by a conventional four-cylinder, 50-horespower Clerget engine. The Clerget was to turn the rotary blades, thus sucking in air through the turbine while “the heat of the exhausting gases…exited...at the rear, driving the plane forward by reaction propulsion,” according to a December 1, 1910, article in the journal La Technique Aeronautique.
Coanda’s patent (French patent No. 416,54, dated October 22, 1910) gives more insight into how the engine actually worked. When air rushed in the front, it passed though different channels that contracted and expanded it. In this way, the air’s “kinetic energy [was] converted into potential energy,” according to the patent. Next, the air was “directed to the diffuser...which then discharges it.”
To improve the efficiency of his machine, Coanda suggested that the channels be heated to increase the pressure of the air passing through them. Any heating agent would work, including exhaust gases from the engine. Moreover, this propulsion system could be applied to any vehicle, said Coanda—including a ship, “motor car,” or airplane.
What is notably lacking in the patent (including identical ones taken out in England and the United States) is any mention of injecting fuel, which in a true jet engine would combust with the incoming air. Judging only by the Turbo-Propulseur’s patent, it was no more than a large ducted fan, a super vacuum cleaner with wings. And it couldn’t have flown.
Throughout the Exposition, Coanda’s airplane was well publicized. Yet none of the reports hinted that the Propulseur on display was capable of actual flight. For instance, L’Aérophile observed: “If the machine would ever materialize as the inventor hoped, it would be a ‘beautiful dream.’ ”
And the accidental flight? At a speech before the Wings Club in New York in January 1956, when Coanda was 69 years old, he said of the Propulseur: “I intended to inject fuel into the air stream, which would be ignited by the exhaust gases....Thus I hoped to obtain the jet reaction desired...” That would appear to close the case: The inventor never finished his invention.
Why then, did he make a contradictory statement in an article published just a few months later in the Royal Air Force Flying Review, titled “It Actually Flew in 1910!” In the September 1956 issue, Coanda is quoted (by writer Rene Aubrey) saying that he did inject fuel. While taxiing and “concentrating on regulating the flow of petrol [gasoline] in the jet engine,” he said, “I suddenly saw the fortifications around the airfield looming up in front of me. There was only one thing to do. I lifted the machine off the ground.” Aubrey then writes that Coanda lost control of the plane and, “Injecting more fuel into the turbine, he suddenly found himself surrounded by flames. Desperately he cut off the fuel. The aircraft stalled and Coanda was thrown clear of the machine as it gently collapsed to the ground and burst into an inferno of fire. Coanda escaped with a few bruises....It was the end of his first jet flight.”
Another article on Coanda, in the March 1967 issue of Flying magazine, gives a precise date for this supposed flight: December 10, 1910. Could the date have been chosen to add authenticity to an unsubstantiated claim? A page-by-page search through the Paris newspaper Le Figaro for the entire month of December 1910 turns up no story about a flight or accident at Issy. Nor is there any mention in leading aviation journals of the day. Nothing. The only reference even closely related, in Flight, reports (under “Doings at Issy”) that in mid-December 1910 there was no flying due to bad weather.
So the claim of a jet flight in 1910 doesn’t hold up to scrutiny, or at the very least needs corroboration. But Coanda’s story doesn’t end there. After the Propulseur was displayed in Paris, he was approached by Grand Duke Cyril, first cousin of Tsar Nicholas II, to make a sled for the Russian royal family. After all, the engine could propel an “aeroplane, ship, motor car, etc.” Coanda built it immediately, with the help of a French boat manufacturer. Instead of a Clerget, he fitted it with a six-cylinder 30-HP Grégoire engine.
The sled had the same inverted flower-pot front, but the body was teardrop-shaped, with two recessed passenger seats at the rear and large snow runners underneath. The sled was exhibited at the Twelfth Automobile Salon of France, also at the Grand Palais, from December 3 to 18, 1910, and was written up in leading car magazines. It was about 13.5 ft long, and was steered with an automobile steering wheel. The accounts say the sled was baptized for Cyril by Russian Orthodox priests using an improvised altar, in a shed usually occupied by motor boats and workmen.
But like the airplane, the sled appears to have been propelled by air alone—not hot exhaust gases produced by combustion, as in a true jet. Motor World called it “more of a ‘wind waggon’ than a tractive vehicle.” No wonder a drawing of it shows two people sitting directly on top of what would have been the turbine’s exhaust exit! Indeed, the passengers would have been cooked instantly if the Propulseur was a real jet.
After spending time and money on his Turbo Propulseur, Coanda may well have discovered that the vehicle’s thrust was embarrassingly feeble for an airplane, and better suited to pushing a sled over ice. Even then, it’s not clear that Cyril’s sled ever worked. The Motor (London) said the inventor claimed it “will be capable of 60 mph.” But no record has been found of an actual run. The Motor only concluded that the sled was to be sent to Russia.
As for Coanda, he was no doubt a skilled aeronautical designer, and became a Romanian national hero (the airport in Bucharest is named after him). But it appears his Turbo-Propulseur may not have quite worked out the way he envisioned. We may never know for sure.
Frank H. Winter is a freelance writer. He was on the staff of the National Air and Space Museum from 1970 to 2007, serving as the Curator of Rocketry.
Comments (7)
If I had money to burn (literally), I'd build a replica of Coanda's airplane and test -once and for all- if it could fly or not. Personally I think it did not fly and if built, can not fly based on the propulsion provided by the contraption at the front.
Posted by Mikhail Kurchatov on December 7,2010 | 02:56 PM
If you ever saw an Airesearch 731 the exhaust is routed just behind the fan--In the front. Just because the common idea is the jet exhaust is out the back, won't discount the Coanda machines. But the low horsepower to the compressor--that would be the limiting factor.
Posted by Don Hillberg on December 10,2010 | 09:11 PM
For the second time in history Mr. Winter makes the same mistake. Please find the debates on going in http://en.wikipedia.org/wiki/Coand%C4%83-1910 Wikipedia for the last 3 months.
What is the "true jet"? Coanda never stated that he invented the turbojet! The engine patented by Coanda works on the main principles of a today's air-breathing jet engine: air intake, centrifugal compressor in a duct, increasing the pressure of the fluid by applying any heating agent before ejection. It is true that the term jet engine is overloaded in English language as described by the language specialists ( check for instance "A history of English words" by Geoffrey Hughes ) but in Latin language families the term, which is plainly described in several French technical publication at the time ( check for instance Bases et Methodes d'etudes aerotechniques - Léon Ventou-Duclaux ) has not changes its meaning over the time, which produces a clash of French and Romanian aviation historians with Mr. Winter's speculations. As well the author of this article missed some other facts as that Gabriel Voisin has witnessed the test at Issy and a book written by Major Victor Houart's "L'Histoire de l'aviation recontee a mon fils" describing in a fashion appropriate to kids the 16th of December test, was endorsed by Voisin. Regarding the sled "Le Figaro" of December 6th 1910 describes that the "This sled was tested at St. Moritz, where it caused a stir". (part 1/2)
Posted by Sorin Lingureanu on December 15,2010 | 11:47 AM
The very expensive project, burning in flames in one its first tests on 16th of December 1910, at the start of his aviation career and in the very middle of the aviation history pioneering, would have been a huge disaster for his future career. This is why he did not wanted to make public such a disaster, especially financial wise ( would have been laughed be the follow aviation pioneers ). In the project, he used as well money borrowed from the Aero Club de France through Ernest Archdeacon, money which were gone a few seconds. Coanda's interest in jet propulsion is shown by his future work, but he lacked the financial support to get his ideas made, especially in France! This is why he moved to England, immediately when it was offered to him.
If you'll check the history of the turbojet you will notice the same facts, the first tests where quite unsuccessful at they were very expensive and Von Ohain stated by himself that he considered to have been was very lucky, to get his idea's put in practice to the end. Coanda and Whittle, sadly, were not so fortunate. (part 2/2)
Posted by Sorin Lingureanu on December 15,2010 | 11:47 AM
Perhaps the Mythbusters have another project?
Posted by heteromeles on December 17,2010 | 09:30 PM
The value of this article is not related to whether this was a true jet or even a failure. All first attempts are failures and even many later attempts. The value is that much of the world believes the Wrights were so far out in front of everyone in terms of sustainable flight that nothing else happened until long after them. In fact, there were people working on real, practical issues with flight dynamics, more efficient propulsion, and experimental shapes and designs, and even advances as "recent" as jet propulsion were considered and attempted at the same time the Flyer flew. Technology often identifies to the "inventor" but there are few core inventions that don't rest on the failures of many past inventors.
Posted by C Bowles on December 29,2010 | 04:27 PM
you know, even now it's hard to find brilliant engineers that are also brilliant pilots. Too bad he wasn't a pilot... If he were, aviation now would probably be extremely different...
If you look on how the planes look like in 1910 it's enough to see how remarkable Coanda's plane was.
Posted by atco on January 4,2011 | 01:19 PM