Juan de la cierva

It all began with Don Juan de la Cierva Codorniu. A Spanish engineer who viewed rotary wing flight as a safer alternative to fixed wing aircraft. 

Cierva initially was involved with fixed wing aircraft design. When a bomber he designed and built for the Spanish military crashed on its first flight due to loss of flying speed in a turn low to the ground he began his pursuit of an aircraft that could safely fly at very low airspeeds. That aircraft is what we know as a gyroplane.

A gyroplane flies due to a concept known as autorotation. Autorotation was not discovered by Cierva but was actually demonstrated by a Russian, Sorokovmovskii, in 1912. Basically, the blades of a rotor will continue to rotate while in a descent thus providing enough lift for a safe landing. 

Cierva submitted his first Spanish patent related to rotary wing flight on July 1, 1920. While Cierva created several versions of the gyroplane it was not until his C.4 that controlled, gyroplane flight was achieved on January 17, 1923. This flight was reminiscent of the Wright brother’s first flight in that it only flew 600 ft at an altitude of just 13 ft but like the Wright brother’s flight it was the beginning of something big. 

The C.4 and all subsequent Cierva gyroplanes incorporated a flapping hinge on the rotor blades. This was the magical solution that prevented the gyroplanes from rolling over on their sides. The C.4 consisted of a four bladed rotor system. 

Captain Joaquin Loriga Taboada made the first cross country flight in a gyroplane on December 12, 1924 in a Cierva model C.6 gyroplane. It was a short flight of 7 ½ miles at 48 mph just outside of Madrid but it demonstrated the future potential of a gyroplane to the Spanish military. Loriga suffered a complete engine failure in the C.6 shortly after takeoff in a climb while demonstrating it to a Vicker’s team from Britain. He was able to land it safely clearly establishing the safe flying characteristics of the gyroplane. Sadly, Loriga was to die in a fixed wing accident in 1927.

Cierva became the first passenger in a gyroplane on July 30, 1926 as it was being flown by his test pilot. Cierva’s C.6D was the first successful two seater gyroplane.

While Cierva was a great designer, he did not become a licensed pilot until January 20, 1927. He eventually became actively involved in the test flying of his gyroplanes as they continued to incorporate new ideas of his to improve their performance and flying characteristics.  The first gyroplane he flew was most likely the C.8R in August of 1927.

Cierva is noted for making the first cross country flight in a gyroplane in the United Kingdom on September 30, 1927 in the C.8L-1. He traveled 44 miles from Hamble to Farnborough via Worthy Down. He is also credited with making the first international flight in a gyroplane flying from London (Croydon) to Paris (Le Bourget) on September 18, 1928. They flew across the water at an altitude of 4,000 ft. 

Cierva made a number of attempts to create a pre-rotation system. While the gyroplanes could land in a relatively small space they required extensive taxiing to get the rotors up to speed thus reducing the practicality of the gyroplane. His most successful attempt at a pre-rotation system came in 1929 and was a deflector stabilizer that redirected the propeller thrust upwards through the rotor. While an improvement over other methods, it could only spin up the rotor to 85 rpm which was a bit shy of the 120 rpm needed to fly and so a degree of taxiing was still required. This unusual system was known as a scorpion tail in Spain. 

Cierva can be credited with the first seaplane gyroplane. It was a variant of the C.17 built in early 1930.  Because of the weight of the floats it was underpowered and never went into production. 

The C.18 completed in June 1929 incorporated the first rotor brake, a staple on all modern gyroplanes. It also was the first cabin gyroplane. 

Cierva is credited with the first truly public display of a gyroplane in the United States on August 20, 1929 using his C.19 MKII model. Hundreds of thousands of spectators saw the amazing capabilities of his gyroplane at the 1929 National Air Races in Cleveland, Ohio. 

In the 1930’s, Cierva worked with the Weir Company to develop small, single seat direct control and jump takeoff gyroplanes for the private aircraft market. 

The C.19 MK V was the first introduction of a direct control rotor head. Up to this point the rotor heads were primarily fixed and control was achieved through conventional control surfaces. The C.19 MK V was purely an experimental platform beginning test flights in March 1932 and never performed satisfactorily to go into production.  

It was the C.30 series that became the first production direct control gyroplanes and the most successful gyroplane ever built by Cierva. He publicly demonstrated this aircraft in April 1933. The advantage of direct control was that it allowed a pilot to exploit the full potential of a gyroplane. At slow speeds conventional control surfaces lose their effectiveness whereas the rotor remains effective while in autorotation regardless of forward speed. The one drawback to direct control was that it induced more vibration in the aircraft than did conventional control surfaces. The rotor was considered so effective that even the rudder was dispensed with in the early models.

The C.30 prototype demonstrated jump takeoff capabilities as early as August 1933 though not completely successful. The C.30 MkIII achieved up to 30 ft jump takeoffs. These were publicly demonstrated on July 23, 1936.

Cierva made the first gyroplane landings on a ship in Europe on a Spanish navy seaplane tender, Dedalo, on March 7, 1934. 

The last British Cierva gyroplanes, the C.40, were built in early 1938 for the Air Ministry.

Cierva was killed in an airplane accident in a DC-2 that took off in heavy fog on December 2, 1936 at the age of 41. Cierva’s legacy is the practical application of autorotation, flapping hinges and drag hinges for rotor blades that contributed directly to the development of the helicopter and, unfortunately, the demise of the gyroplane. 

Cierva’s last known pilot logbook entry was made in October 1935 showing a total of 735 hours of flight time. 

Cierva’s board decided to abandon Autogiro development in early spring 1939. Pitcairn continued autogiro development in the U.S. into the early 1940’s.  

Cierva Awards

1930 Medalla de Oro del Trabajo by Spanish government

1931 British Royal Aeronautical Society Silver Medal

1932 Daniel Guggenheim Gold Medal

1933 Federation Aeronautique International (FAI) Gold Medal

1933 Elliott Cresson Medal awarded by Franklin Institute of Philadelphia

1934 Wakefield Gold Medal

References: 

Wikipedia

Wings of Tomorrow by Juan de la Cierva

Legacy of Wings by Frank Kingston Smith

Cierva Autogiros by Peter W. Brooks