Many doubts about that. In september 1943 the P.XIX was already in service, with the Re.2002, and, in the "experimentals" is listed almost everithing. The P.XV was not mass produced, but was well tested on several aircrafts without showing problems. The Zeta was tested, but had several problems. As far as I know, not a single prototype of the IF Sigma was assembled, while the Fiat "X" engines were probably not ready even on the drawing board.
I begin my replies to the third critics.
Yes, there are different errors. But you tell something not supported by data or bibliography...: "As far as i know..."
I told that i found the scheme in the following article (but obviously you do not read all the text): Giuseppe Pesce (author), Motori radiali nella Regia Aeronautica, in: Rivista aeronautica, 1989, n.1, gennaio-febbraio, page 111 (table), pages 106 to 113 (article).
So this isn't my work! It's the Giuseppe Pesce work. Do you know Giuseppe Pesce? A General of the Aeronautica Militare Italiana (Italian Air Force), and founder of the Vigna di Valle Museum. You could turn your criticism to him but unfortunately he died in 2009.
About Zeta and its problems, every engine needs a development period. As the example of wuzak has well explained. But the attempt to solve the problems of the lack of an engine during the course of a war when it was not done in time of peace, it was obviously useless and pathetic! Especially because the Italian engineers had the technical knowledge. But not the adequate support of the ruling class. And infact the engeneer Federico Filippi wrote "Troppi erano gli "handicap" contro cui battersi: la indisponibilità di carburante con N.O. superiore a 83-87, la indisponibilità di materiali di alte caratteristiche (che dovevano essere sostituiti con materiali "autarchici"), la mancanza di centri di ricerca governativi per le ricerche fondamentali (per esempio: lo sviluppo di compressori efficienti) o di finanziamenti per prototipi che non fossero destinati a battere qualche record, un'errata impostazione tecnico-militare, la dispersione degli sforzi tra una molteplicità di costruttori."
Translation: "Too many were the "handicap" against which to fight: the unavailability of fuel with a higher octane number 83-87, the unavailability of materials of high characteristics (materials that had to be replaced with "self-sufficient"), the lack of government research for fundamental research (for example: the development of efficient supercharger) or funding for prototypes that were not destined to beat some records, a military-technical incorrect setting, the dispersion of effort between a variety of manufacturers." (Federico Filippi, 1983, "Dall'elica al getto. Breve storia dei propulsori aeronautici", Associazione Industriale Metallurgici Meccanici Affini, Edizioni EDA [publisher], page 44 ).
Although I agree with much of the speech, i'm not entirely agree with all arguments. Especially on the issue of materials and autarchy. In fact, the lack of raw materials was not just about Italy. It was also a problem for Germany. But the Germans were still a bad deal for the Allies. And how it was possible to build some prototypes in time of war, hampered by strategic and materials constraints, when they were not built in time of peace? Why were not certain research conducted in peacetime? How can such a sudden increase in the ratio CV/L between 1938 and 1942 without improvements to existing engines and research? Because there were no engines with intermediate power ratio?
The numerous mistakes testify of the lack in Italy of a detailed historical research about engines.
It seems to me that the lack of improvements was in the period 1928-1937, during which tha Isotta Fraschini Asso W18 products became naval engines, and all the experience gained with the AS5-AS6, led to the anemic A.30. Just think of the long operating life (for the time) of the Isotta Fraschini Asso 750. And his replacement, the Asso XI was not more powerful, than the Asso 750 was in early '30s, but just a little smaller.
At the Aviation Exibition of Milan in 1937, some very interesting engine was presented, as the Alfa Romeo A.135, or several IF products, but they were only at first stage of developement, and, in the subsequent two years, the goal was to solve their problems, and put them in production using autarchic materials. They have been two years of hard work compared to the previous ones.
In the end, when the Piaggio P.XII was homologated, at the end of 1939, there were not many engines who could confront him using 87 octane gasoline. Then, during the war, the gasoline made the difference.
Why did you tell that the lack of improvements was in the period 1928-1937? AS5 ran in 1929. AS6 ran between 1931 and 1934. The A.30 (why anemic?) was a AS5 evolution. It was the CR30 and CR32 engine. Both excellent aircraft. And the final (unfortunately!) A.30 evolution was the A.33. Better than the contemporary A.74 or A.80. If you don't believe, you colud see the ratio between the power and the displacement (CV/L = Metric horsepower/liter). I use continuous power output because italian engine data show the continuous power at altitude and the maximum take-off.
So i've created two pdf documents.
In the first there is a timeline chart of the italian engines followed by data about the engines. It isn't a perfect work. I know it. Probably there are still several errors. But I consider it a work useful enough to make me understand.
View attachment 232611
In the second document there is a list of the most important engines of World War II, with some useful information for comparison.
View attachment 232612
You, Dogwalker, don't consider the difference necessarily due to the displacement of the engines. For example, the Asso XI wasn't "just a little smaller" than the Asso 750 (32.144 liters against 47.105 liters). And the Piaggio P.XII is bigger, but it had a lower CV/L. It was not very efficient.
And the Asso XI had a similar displacement to the A.74.
Excuse me. I'm tired of rumors that are not supported by actual data on Italian aircraft engines. Legends born do not know when. But that became TRUTH.
Give me real informations, true, specific, and I believe these rumors.
