Experiments with Canovetti
Mario Calderara writes as follows in a memorandum written in Paris in 1935 entitled “I miei ricordi di aviazione” (My recollections of aviation):
“In 1902, I decided to cooperate with an Italian engineer (Mr Canovetti), for the development of an experiment which attempted to establish the value of the coefficient “K” of resistance of the air, which at the time was evaluated quite wrongly. Our experiments took place on the funicular between Como and Brunate which was not operating during the winter. The carts had been loaded with surfaces having different shapes and dimensions; they were allowed to fall freely along the rails, and their velocity was recorded at regular intervals. Thus we succeeded in evaluating the coefficient of resistance of the air and its influence in function of the surfaces with an approximation which had never been attained before. In fact, these values are very close to those obtained today in the expensive wind tunnels utilized to this effect”.
In a later edition of his memories, Calderara mentions the experiments as having been carried out “in February 1903” but as their preparation must have started at the end of 1902, the conflict of dates does not appear to be very important (at that time Calderara was 23 years old).
Mr Canovetti was born in Florence in 1853; he graduated as an engineer in Paris. He made valuable technical studies, and published some papers which received prizes from scientific institutes, including the French Academy. In 1898 he was authorized by the Brescia municipality to install a cable stretched between a tower in a city castle and the bottom of a moat, with a level differential of 81 meters and a cable length of 170 meters. Some carts running along the cable were loaded with surfaces and volumes of different shapes. Between 1902 and 1904 he improved his experiments using a cable between Brunate and Como, with a length of 800 meters… (omissis) …
Gliding Experiments
Following is a transcription of the first part of the report entitled “Experiments with airplanes” presented by Calderara to the Ministry of the Italian Navy on July 26, 1907:
“I would like to inform briefly this authority about the present state of the well known experiments with airplanes for which I am ready to submit a complete and detailed report. The tests which have been carried out so far are of two types:
1. GLIDING EXPERIENCES: (these words are both in Italian and in English in the text). These are a reproduction (I trust it is a faithful one) of the well known experiments of the American Chanute and they have allowed me repeatedly to cover a distance of 15 to 50 meters in a straight line while being lifted to a height of 50 cm to 3 meters. These preliminary experiments had the double aim of verifying the data which I had received (in which I could not find any artificial exaggeration) and of acquiring a certain mastery of the machine which will prove very useful in case of breakage or hooking of the towing cable during final tests. As I operated the machine repeatedly and continuously I acquired the reflexed movements (as opposed to the instinctive ones) required to balance and control the flight, and acquired also a certain amount of self assurance which will allow me to repeat these glidings whenever I will be requested to do so, as long as weather and site conditions will allow them.. These conditions consist in the availability of a sloped meadow (inclined 20 to 30 degrees) with a wind blowing uphill at a minimum speed of 7 meters per second. The length of the flight depends almost exclusively from the extension of the slope.
2. TOWING EXPERIMENTS.
2.1. TOWING ON SOLID GROUND: When there was a strong wind I succeeded in being towed on a flying machine used like a kite, pulled by two persons who ran against the wind. The combined speed of the runners and the wind allowed me to be lifted to a height of 4 meters in a stable and continuous way , and I could have increased that height if I had not chosen to avoid useless risks. This type of test does not require like the preceding one a methodical preparation, and can be repeated at any time. A possible ground for these tests is the “Piazza d’Armi” in La Spezia.
2.2. TOWING EXPERIMENTS AT SEA:. In the report which I had the honor of submitting when I proposed the present experiments” … (omissis) … (Calderara discusses the well known tests of gliders towed by motor boats and war ships, which ended with the “Lanciere” accident).
When did these early experiments take place
Establishing the dates of the early flying experiments described by Mario Calderara seems rather difficult, because Calderara himself does not mention any dates in his report to the Ministry… Before 1904 he could presumably rely only on vague reproductions of the Chanute gliders, and he must have also utilized his own capacity for design. This explains also why he neglected to show details of his early gliders, as he must have thought that their design was obsolete with respect to the more advanced technical information obtained from the Wright brothers.
Therefore we can only surmise that these flights took place in 1904 –or early 1905, i.e. before Calderara started his correspondence with Dayton, and before he presented (end of 1905) his first proposal to the Ministry for using large kites of the “Hargrave” type to lift observers high above war ships. Calderara mentions in his memories that in 1905 he did not dare (not yet) to propose towing real “gliding-airplane, because he feared that the conservative senior officers who analyzed his proposal would find it unfeasible and even ridiculous”.