The First Jet:
Before Whittle, Before Heinkel, Before even Caproni, Romanian Aviator Henri
Coanda takes to the skys.... in 1910
Just seven years after the first flight by the Wright Brothers,Henri Coanda flew the first jet powered aircraft. Working for the British aviation company, Bristol, Coanda designed a series of
aircraft. The Coanda 1 was the most striking. His engine used a combustion engine to drive a compressor and injected fuel into the compressed air before igniting it, a concept later called a
"Thermojet". The engine produced thrust by ejecting the high pressure burning gasses. Coanda called his engine a "Reaction Motor". His design was years ahead of its time. In contrast, the
Caproni CC2 first flew in 1940.
The Coanda 1 was a single seat biplane with several novel design features.
force at sea level:
|| 220 kgf
||485 lb (thrust)
The wing structure was built up from metal tubular spars. This was a feature that had not been used before, all previous aircraft designers had used wood exclusively.
The airframe had several drag reducing features. The fuel was stored inside the top wing, and the rounded wingtips helped prevent a stall. The plane even had lift inducing flaps, similar in function to the "Fowler flaps"
use on modern aircraft. The wing plan was novel too. The aviation term "sesquiplan" had not been invented in 1910, but this is what the Coanda was. The two wings had different lengths, with the upper wing being longer
and broader than the lower wing. This feature helps prevent wingtip stalls and also reduces drag. The upper wing was also set ahead of the lower wing. This prevents the airflows interfering with each other and
has the added benefit of lending more forgiving responses during a flat spin. Novel at the time, the feature became standard in Nieuport, Breguet, Potez and Fokker aircraft in World War One.
This construction, applied for the first time by Henri Coanda, was later called 'Sesquiplan'; it was re-invented 10 years later, being used for Fokker's, Brequet's, Potez's airplanes.
The most interesting part of Coanda's plane was the propulsion system, a real revolution in the construction of airplanes engines, that would have to constitute the solution in the future.
The Reaction Motor" designed by Henri Coanda had at its heart a 50HP combustion engine. This drove a compressor through a gear box at 4000 revolutions per minute. Ahead of the compressor was a controllable iris, that regulated
the flow of air through the engine. Behind the iris, combustion engine and compressor lay a ring of combustion chambers. The air was ejected with a force of 220KG thrust. (In comparison, the thrust of the Heinkel HeS 3
turbojet of the Heinkel He 178, invented nearly thirty years later, developed 450KG thrust.)
On December 16, 1910, Henri Coanda transported his airplane at Issy-les-Moulineaux. His intention was to "warm up" the engine and taxi, not to fly.. So Coanda got into his machine, and after several minutes of warming up,
pushed the buttons that commanded the obturator and the rotation speed of the engine. The airplane began to move faster and faster, and flames and fume could be seen along the fuselage getting out from the engine. After a very short time,
before Coanda could realize what was going on, the airplane was in the air. Impressed by the flames and worried about the fact that he had only piloted gliders beforehand, never a powered aircraft, Coanda lost the control of his
machine which began to loose speed and height. In a short time it struck the ground and began to burn. Coanda was thrown clear and lived to tell the tale.
This first flight was described by Coanda in 1964 thus :
"The machine gained height much faster than I thought; it was not my fault,
but after a while it entered a stall, struck the ground and burned completely. I
was very lucky I was not tied on the chair, such that I was pushed out when the
airplane struck the ground; otherwise I would have burned with it."
Following this episode, the unforgiving public dismissed Coanda's creation as a folly. They had not realised that the engine and aerodynamic refinements were years ahead of their time. The prospects for aircraft
design could have been forwarded twenty years had Coanda been able to get backing. For its time the Coanda 1 was an incredibly powerful aircraft, as the table below shows:
||Thrust to weight ratio
Bereznyak-Isayev BI rocket fighter
||1 : 2.65
||F80 Shooting Star
With a the aerodynamic refinements Coanda's aircraft could have heralded a leap forward in design, but , other than underestimating the sheer
power of the engine, Coanda made one critical mistake and built in a near fatal design flaw. Remember that this aircraft flew at the time that canvass was stretched over the airframe with highly flammable dope!
During the machine's short flight, Coanda was able to observe that the burning gasses from the engine seemed to hug the sides of the aircraft very closely and this is what seemed to cause the fire. He spent many years
researching this effect, which is now known as the
Coanda Effect a term coined by Albert Metral after Romanian inventor Henri Coanda. The Coanda Effect is the tendency of a stream of fluid to stay attached to a convex surface, rather
than follow a straight line in its original direction.
The Coanda Effect has important applications in various high-lift devices on aircraft, where air moving over the wing can be "bent down" towards
the ground using flaps. Several aircraft have been built to take advantage of this effect by mounting jet engines on the top of wing to provide high-speed air even at low flying speeds, but to date only one aircraft has gone into
production using this system, the Antonov An-72 Coaler.
The kit is a available from Digital Card Models at $4.99.
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