Leonce Bertin was quite an inventive fellow. He also designed a helicopter first in 1908, and again in 1912. The 1912 model appears to be powered with a 4 cyl version of his neat little engine.

What is more - the rotor was designed in the shape of an aerofoil, rather than a propeller shape, as in current (rotary wing) design. This shows Bertin was aware that more than a simple propeller was needed for lift.

The 1908 model utilised biplane aerofoils, but the 1912 version utilised a monoplane wing.

There is a photo on the 'net (not readily accessible) of Leonce and his son Rene in the Bertin monoplane, apparently taken on the day they crashed (14th July 1913), which resulted in the death of both father and son.

Bertin helicopter - 1908

Alamy stock photos - the 1912 Bertin Helicopter

Here's an obviously rare photo of Leonce Bertin from 1910, posing alongside what appears to be one of his earlier engines, a single cylinder version.

The hypnotic stare of Bertin into the camera lens appears to me, to indicate a man of great intensity and drive.

Leonce Bertin - 1910

I find the fact that a large number of these early flyers, tinkerers, and aircraft engine and airframe builders, seem to originate from the bicycle and motorcycle fraternity.

Bertin was a bicycle mechanic, then a motorcycle mechanic. I guess dealing with light weights and small engines, as in motorbikes, would translate pretty easily across to flying machines.

I think it also helped to be a bit of a mad bugger, a real risk-taker, as so many of the motorcycling and motorcycle racing fraternity seem to be, both then and now.