Don Dido Marchesi's "geidroplane", the first jet plane - the Harrier fifty years before the HS Harrier

[ermeio]

Don Dido Marchesi, parish priest of Montebudello, a town in the Bolognese hills, was the first in Italy to experiment with a jet-powered flying machine.
In 1917 he published a study on a strange aircraft without propeller and without wings, equipped with an acetylene burst propeller, called a “geidroplane”.
In the utopian intentions of its inventor it is a multipurpose machine, capable of flying, navigating and racing on the road.
However, the experimental tests will not be crowned with success: one of the prototypes, powered by acetylene, will even explode. This will not prevent the priest-inventor from receiving the honor of Knight of the Crown in 1924.
I have found some information about this strange apparat. The plane had to lift only with the thrust of the air generated by the engine and blown through two nozzles on the fuselage sides and had no wings.

 

[klem]

Still from the same inventor "geidrovolante" model n°2.

 

[UpForce]

Rough translation of the legend: "D. Marchesi's machine. M motor - C compressor - a suction - p pressure pipe that introduces the air into the rear tank regulator S - q t supply pipes of the nozzles u, whose supply is made with the valve R (lever h) and whose inclination is controlled with lever L."

So this is a radial internal combustion engine (it looks like, fueled by acetylene?) driving a compressor which in turn feeds a pressurized air tank in the rear of the vehicle (the tank is not obvious in the picture unless the whole of the rear doubles as a vessel, something that seems unlikely). The pressure is released by the pilot with a valve and vectored in two axes with a lever; I'm assuming that for full control there must be separate valves and levers for each nozzle but this doesn't seem to be specified. In any case, operating all the functions appears to be quite a challenge even with the most ergonomic of designs and there's no mention of how (or if) the radial engine is controlled.

Thrust is supposed to be produced by air pressure alone or, and this doesn't seem to be the case (the nozzles are small and very close to the fuselage and the pilot), the nozzle doubles as some kind of an acetylene afterburner for added thrust. An acetylene/air mix could also be burned after or within the mechanical compressor and prior to the pressurized tank in the rear but this is speculation and not evidenced by anything in the drawing. It's perhaps somewhat unlikely, though, if in 1917 someone had thought mechanically produced air pressure alone would suffice for this application. The compressor seems large, its exact function also unspecified.

An optimistic design, with shades indeed of Harrier but equally perhaps of Caproni Campini's motorjet. One could even say that C.C.2's operation is something of a simplification (but also, of course, a more rational and evolved application) of D. Marchesi's budding ideas.

Edit: Klem seems to have come up with more information, perhaps I'll come back to it later. The "geidrovolante" seems to have sprouted wings.

 

[ermeio]

No, the inventor of the small apparat "geoidrovolante n°2" is Emilio Marchesi, Don Dido's brother . He wrote some boklets and you can find a digital copy of the booklet Geidrovolante : apparecchio d'azione senza elica e senza piani : deduzioni teoriche ed esperimenti fatti con piccoli apparecchi on the website of the national library in Rome:

Libri - Biblioteca nazionale centrale di Roma

I did not have time to translate it, but it seems interesting.
erme