The du Temple Monoplane “Canot planeur” of 1874 might have been realized by Félix du Temple de la Croix (1823-1890) from his 1857 patent. The du Temple Monoplane was a steam-powered aircraft made of aluminium, built in Brest, France, by naval officer Félix du Temple.

The aircraft used a very compact, high-speed circulation steam engine for which Félix du Temple applied for a patent on 28 April 1876. The engine used very small pipes packed together to obtain the highest possible contact surface for the smallest possible volume.

When he began with the aid of his brother, M. Louis du Temple, to experiment on a large scale, the inadequacy of all motors then known became apparent. They first tried steam at very high pressures, then a hot-air engine, and finally built and patented, in 1876 a very light steam boiler weighing from 39 to 44 lb. to the horse power, which appears to have been the prototype of some of the light boilers which have since been constructed. It consisted in a series of very thin tubes less than 1/8 in. in internal diameter, through which water circulated very rapidly, and was flashed into steam by the surrounding flame.

This type of boiler, which boils the water instantly, has come to be known as a flash boiler. The engine design was later adopted by the French Navy for the propulsion of the first French torpedo boats.

Variously reported as steam powered or powered by a hot-air engine; fitted with a propeller of 12 blades or 6 blades or even 8 blades; and the undercarriage sometimes claimed as “retracting”.

A flight of the full-scale machine was attempted in 1874 in Brest, where it was launched from a ramp. Several trials were made with the aircraft, and it is generally recognized that it achieved lift-off – described by Dollfus as “short hop or leap” and in Flight International as “staggered briefly into the air” – (from a combination of its own power and running down an inclined ramp), glided for a short time and returned safely to the ground, making it the first successful powered flight in history though not the first self-powered one. Flight was not attained as the machine swiftly hit the ground and rolled over. Reports on who was in the pilot’s seat is given that du Temple at the controls – or, in other reports – a “young sailor” was the pilot.

Félix du Temple had been the first to build a heavier-than-air model (weight 700 g), which flew and landed safely in 1857.

It had a wingspan of 13 m (43 ft) and weighed 80 kg (180 lb) without the pilot.

Ader’s progress attracted the interest of the minister of war, Charles de Freycinet. With the backing of the French War Office, Ader developed and constructed the Avion III (with the help of Ing. Morel). It resembled an enormous bat made of linen and wood, equipped with two four bladed tractor propellers, each powered by a steam engine of 30 hp (22 kW). Using a circular track at Satory, Ader carried out taxiing trials at the Satory army base near Versailles on 12 October 1897 with the aircraft taxiing along a circular track, and two days later attempted a flight. After a short run the machine was caught by a gust of wind, slewed off the track, and came to a stop. After this the French army withdrew its funding, but kept the results secret. After the Wright brothers made their flight, the commission released in November 1910 the official reports on Ader’s attempted flights, stating that they were unsuccessful.

The Avion III had a 52 ft 6 in (16.0 m) wing span, gross weight of about 882 lb (400 kg).

Ader Avion
First flight: 1897
Wing span: 17m / 56 ft
Weight: 400 kg / 882 lb

Clément Ader turned to the problem of mechanical flight and until the end of his life gave much time and money to this. Using the studies of Louis Pierre Mouillard (1834–1897) on the flight of birds, he constructed his first flying machine in 1886, the Éole. It was a bat-like design run by a lightweight steam engine of his own invention, with 4 cylinders developing 20 horsepower (15 kW), driving a four-blade propeller. The engine weighed no more than 4 kg/kW (7 pounds per horsepower). The wings had a span of 14 m (46 ft). All-up weight was 300 kg (650 lb). On 9 October 1890, Ader attempted a flight of the Éole, in the grounds of the Chateau Pereire at Armainvilliers. It is accepted that the aircraft took off, reaching a height of 20 cm, (8 in) and flew uncontrolled for approximately 50 m (160 ft), 13 years before the Wright Brothers.

Engine: One 20 hp Ader four-cylinder steam engine
Prop: 4 blade tractor propeller, approx 11 ft 6 in (3.50 m) dia.
Wing span: 45 ft 11 in (14.00 m)
Wing area: 301.4 sq ft (28.0 sq.m)
Length: 21 ft 4 in (6.50 m)
Weight empty: 498 lb (226 kg)
Gross weight: 652 lb (296 kg)
Accommodation: Crew of 1