Rooivalk Attack Helicopter
An interesting question with many answers. Case history tells us that a big drawback in the early design phases was the power to weight ratio of the engines at the time. Leonardo da Vinci drew the plans for a device which used the Archimedes screw, in this case, an ‘aerial screw’ for lifting the prime mover. His models do not show a counter rotor which is needed to prevent the helicopter or flying machine from rotating counter to the screw rotational direction. To cut to the chase there were many ‘inventions’ but none that could really be flown or at least in the modern sense be practical e.g. to be used to lift a considerable weight and fly (or at least be piloted).
1900 – 1920
Jacques and Louis Breguet are credited for being the first to remain in the air in a primitive contraption called the Gyroplane No.1 – however as it was tethered the record remains dubious. This took place sometime around 1907/1908.
Paul Cornu did remain in the air without tether and may be known for being the first to actually pilot a helicopter, however primitive the airframe.
1920-1930
The first vehicle used with cyclic pitch control is credited to an Argentinian Raúl Pateras-Pescara de Castelluccio.
Spaniard Juan de la Cierva – contra-rotating rotors.
Dutchman Albert Gillis von Baumhauer – inventor of the cyclic and collective controls also promoted the further research into helicopter design.
A personal favourite to many however would be Igor Sikorsky’s design, a simple two bladed rear rotor – the first practical and commercial design was the R-4. It’s based on this achievement that Sikorsky is often known as the father of the helicopter although obviously credit must be given to the other pioneers mentioned previously. Sikorsky also had military backing which inevitably expedites any design process. The Germans and Russians had their own program and in many ways this was far advanced to that of the British and Americans in the 1940s. For commercial aircraft however Bell Aircraft were pioneers in their own right and to this day are the benchmark in helicopter design.