FIAT A.S.8 ENGINE. (1 Viewer)

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Forgive the thread necromancy but does anyone have any information on boost pressure for this engine? What grade of fuel was used, as it was designed for a record attempt I assume it would have burned a 'witches brew' with a higher octane rating than the 87 that was standard in 1940-41 for the Regia Aeronautica.

What are good sources for information on ww2 era Italian engine projects? Sources in English or Italian would be welcomed.
 
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Hi everyone. Ciao a tutti.
Sono anch'io seminuovo in questo forum. I am almost new in this forum too.
Questo è un ottimo argomento. This is a great topic.
My english is bad so i hope that Marcogrifo could help me in the translation.

@Nick Sumner. I don't know about boost or grade of fuel. Sorry. I'd like to know them too.
I know that AS8 was a race engine. And a sort of its evolution was Fiat A.38 RC 15/45.
This one run for the first time in 1941. This was a good alternative to DB 605. Infact the continuous power output at altitude (1500 meters and 4500 meters) was 1200 cv (1183 hp). The DB605A continuous output was 1080 PS (or CV), circa 1065 hp.
There was problems because it was projected in 1940. The crankshaft was long. And there's no time for the setup... So it was abandoned in 1942!
If you think that Merlin had a long setup (i don't know if "setup" is the best english term... Come si traduce "messa a punto"?).
I post some data about Fiat A.38 RC 15/45
FIAT A 38 RC 15-45 - 01.jpg
FIAT A 38 RC 15-45 - 02.jpg
FIAT A 38 RC 15-45 - 03.jpg

A further evolution was probably the FIAT A.44 RC 15/45, an X inline engine with 32 pistons producing 2800 cv (2760 hp) at takeoff! Its displacement was probably double to A.38: 69.4 liters.
This is a table of italian engines until 8 september 1943. It's missing some engines. And the power output refers to takeoff. But i'm not sure for every engine...
From: Giuseppe Pesce (author), Motori radiali nella Regia Aeronautica, in: Rivista aeronautica, 1989, n.1, gennaio-febbraio, page 111 (table), pages 106 to 113 (article).
Elenco motori Regia al 1943.jpg
 
A.38 was born as a V16 engine. Like A.S.8. Then during the development the V was inverted.

About A.S.8.
In the Aerofan magazine n.1, year 1980, it appeared a short article about this engine at pages 39-40.
The two pages about A.S.8
View attachment FIAT AS 8 - Aerofan n.1 1980 - pp 39-40.pdf

And the Aerofan n.1, 1980
View attachment Aerofan - 1980-01.pdf

But in the Aerofan n.4, year 1980, there were two letters at pages 140 and 141.
View attachment AeroFan 1980-4.pdf

The first from Oscar Marchi (an important aeronautics italian divulgator) and the latter from the professor (at Politecnico di Torino) and engineer Federico Filippi.
They complained that the item was entirelly copied from an older Filippi article (including commas and errors):
Federico Filippi, Appunti per una storia del motore aeronautico in Italia, in: «Atti e Rassegna Tecnica della Società degli Ingegneri e Architetti in Torino», ottobre, 1965.
I like to have this article.
Prof. Filippi in the letter told us that his old article had differe historical and techincal mistakes. He also offered himself to write a new and updated article. But never did it! I suppose probably because the many idiosyncrasies and diffidence between researchers in Italy...
Infact nobody have studied the documents about engines in the Fiat, Alfa Romeo, Isotta Fraschini and Aeronautica (italian air force) historical archieves...
And so we have many mistakes about italian engines, their evolution and why italian industry wasn't capable to produce a very modern homemade engine.
I think that the problems were due to political incompetence, to clientelism and to contrasts between different potentates (political, industrial...).
Infact too much engines were not improved during their life. For example Fiat A.74 first run in 1935 but it was never updated (apart the too late attempt with A.76, that had a bigger displacement and other improvements). There was a lack of improvements during the 1937-1940 period. When all the other most important nations in the world began to improve their engines before the beginning of the war.
When the politicians and military elite understood that it was a great problem it was too late. Nevertheless the industry was capable to produce different interesting prototypes. But too late.
It's incredible to see the differences between never improved older engines (like A.74) and the next prototypes. Doubtless this wasn't a technical lack of knowledge.
 
I am just guessing but perhaps they tried starting over too often in comparison to modifying, updating existing designs?

The P W R-1830 started as a 750-800hp at 2300-2400rpm on 80-87 octane fuel. It got new main bearings, the cylinders were changed twice if not three times and a number of other modifications to get to 1100-1200hp and 2700rpm. It sure was not a case of pour 100 octane in the tank and go :)

There may have been things they would have liked to change but didn't in the 4-5 years it took to go from 800 to 1200hp. Perhaps the Italians tried to redo too many things at once?
 
YES, for the first question. And (probably, i need more data) YES for the latter question.
But there was a period (circa 1936-39) were the politicians (fascists) and the military hierarchy maybe thought to already have everything in place, in addition to the error to focus only on FIAT radial engines. FIAT was a monopolist in Italy. And the Agnelli family (owners of FIAT) had different supporter in the fascist regime...
Fiat woke up only when there was a danger of losing the job (in 1939 Alfa Romeo acquired the license for the production of DB 601Aa). There were different events like this...
 
A further evolution was probably the FIAT A.44 RC 15/45, an X inline engine with 32 pistons producing 2800 cv (2760 hp) at takeoff! Its displacement was probably double to A.38: 69.4 liters.

According to your chart, the A.44 was 100 litres.


There was problems because it was projected in 1940. The crankshaft was long. And there's no time for the setup... So it was abandoned in 1942!
If you think that Merlin had a long setup (i don't know if "setup" is the best english term... Come si traduce "messa a punto"?)

I think for "setup" you mean development period.
 
Merlin development started around 1931/32. The first V-12 ran on the bench in October 1933. First flight was in February 1935. The Merlin I started production around 1935/36, the Merlin II in 1937. The Merlin I had the "ramp head", and was problematic. The Merlin II adopted the single piece block/head design of the Kestrel. There were still issues with coolant leaks until the two piece block heads were introduced in 1941/42.

Using that as a basis, 4 to 5 years from conception to production would seem reasonable. That said, the R-4360 managed to do it in half that, possible because it used a lot of R-2800 components, at least at the start, and din't require the single cylinder development cycle.
 
Sibboh - thank you for your reply!

Wuzak, I think 'superficie frontale dm2' means 'frontal area in square decametres'.
 
I have put the Aero Fan article through machine translation (Google translate) and this is what comes out.

This engine was the direct descendant of the legendary AS6 mounted on the Macchi M C.72 who conquered the speed record for seaplanes in 1934, still undefeated.

He was put to the study in order to regain the primacy of speed conquered by a German plane, but not only was this the reason that the port RA the study of this powerful engine, the most valid reason was the urgent needs of drivers of high-power unit to be installed on fighter aircraft.

The AS8 maintained dell'AS6 some constructive features, including the use of counter-rotating propellers that were no longer independent but mechanically as derived from the motion of a single dual-output gearbox, ALMOST authentic was the compressor which provided a pressure maximum of 1350 mmHg.

To avoid the danger of torsional vibrations, easy to get excited in a crankshaft with 8 cranks, the command of the distribution and of the auxiliary was derived in the vicinity of the gearbox, and that means in correspondence of a presumable node of oscillation.

The first bench tests were performed at the beginning of 1940, demonstrating exceptional strength: for the AS6-hour test was a limit beyond which it was not prudent to go, the AS8 very brilliantly overcome a test of 100 hours.

For the development of this engine, Fiat, mindful of the experience of 1'AS6, had even built a dedicated experimental station on the banks of the river Sangone, near Mirafiori, either by setting up a Brown Boveri Turbocharger capable of creating a wind relative to 1000 HP / h.

Soon, however, given the exuberant power and unworkable, for the type of aircraft that you wanted to achieve, was abandoned in favors of the license to reproduce the engine Daimler-Benz DB 605.


characteristics

16-cylinder engine, V-45 with provision in two groups, counter-rotating propellers, fitted with a reducer and a compressor to the exhaust gas. Liquid cooling.


From this we know that the supercharger delivered 1350 mm of mercury which corresponds to 26 psi (using UK boost pressure measurement). To put that in context it was only with post war Merlin 100 series engines that 25 psi boost was cleared for use.

Perhaps our italian speakers could help with the translation of the second to last paragraph

Per la messa a punto di questo motore la Fiat, memore dell'esperienza fatta con 1'A.S.6, aveva addrittura co¬struito un'apposita stazione sperimentale sulle rive del torrente Sangone, vicino a Mirafiori, installandovi una turbosoffiante Brown Boveri capace di creare un vento
relativo di 1000 CV/h.


I'm not convinced Google translate has it correct and what is CV/h - HP/?
 
CV/H could it be related to constant (safe/reliable) power per hour?
And Google translate is sort of ok, but it is known not to be good at alternate meanings and some technical words.

I think 'hour' in Italian is 'ore' (?) so I assume the 'h' here means something else.
 
Yes, "ora" means "hour". But anyway we use "h" for ora/hour.
@Nick Sumner. Good translater! 'superficie frontale dm2' means 'frontal area in square decametres' (correct!)
In the article the author wanted to demonstrate that radial engines greater frontal area reduces fighter performances more than the inline engines.
Infact US technicians resolve the problem with a very powerful engine like R-2800. In Italy at the time there is the Fiat A.74...

"Per la messa a punto di questo motore la Fiat, memore dell'esperienza fatta con 1'A.S.6 (there's an error: not "1" but l'A.S.6. This means simply "the"), aveva addrittura costruito un'apposita stazione sperimentale sulle rive del torrente Sangone, vicino a Mirafiori, installandovi una turbosoffiante Brown Boveri capace di creare un vento
relativo di 1000 CV/h."

"For the development of this engine, Fiat, mindful of the experience of the AS6, had even built a dedicated experimental station on the banks of the river Sangone, near Mirafiori, by setting up a Brown Boveri Turbocharger (i don't know if turbocharger is the perfect translation, but yes, a sort of it) capable of creating a wind relative to 1000 CV/h (i want to remember that CV and HP aren't coinciding)."

The translation is good. But i'm not a good english writer... :p

@wuzak. What you say is just what I wanted to express!
"Merlin development started around 1931/32. The first V-12 ran on the bench in October 1933. First flight was in February 1935. The Merlin I started production around 1935/36, the Merlin II in 1937. The Merlin I had the "ramp head", and was problematic. The Merlin II adopted the single piece block/head design of the Kestrel. There were still issues with coolant leaks until the two piece block heads were introduced in 1941/42.
Using that as a basis, 4 to 5 years from conception to production would seem reasonable. That said, the R-4360 managed to do it in half that, possible because it used a lot of R-2800 components, at least at the start, and din't require the single cylinder development cycle.
"

A.S.8 was only a racer engine (like Rolls-Royce R). The boost pressure is high only because it's exceptional. A production engine like possibly A.38 would have a lower maximum boost (i'll post some data about another project: the Reggiane Re.103).
Italian engineers used to increase the continuous power output. Instead the English and US engineers increased the continuous output only at the beginning. Then they focused mainly on combat, military and emergency output. We have few data about combat and emergency output in italian engines. But these few data tell us that the ratio between maximum power and continuous power was lower than in the allied engines. Like for the german engines. I think it was a different development strategy. Maybe losing... :-S
 
@Shortround6 You tell: "The P W R-1830 started as a 750-800hp at 2300-2400rpm on 80-87 octane fuel. It got new main bearings, the cylinders were changed twice if not three times and a number of other modifications to get to 1100-1200hp and 2700rpm". I like to have more information like this about the evolution of US engines. Where could i find them?
 
There was a lack of improvements during the 1937-1940 period.
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.

in addition to the error to focus only on FIAT radial engines.
The decision was to relay on radials, and, in the early '30s, it seemed not a wrong one. When the single alluminium cylinder cast tecnology was introduced for the radials, the power/weight ratio of radials, jumped beyond what could be achieved with in-line engines, and without having their side problems. In the early '30 the radials seemed the last frontier in Aero Engines developement, and only slowly the inlines regain the lost ground. Is revealing that several of the inlines that were used at the beginning of the war (and sometimes until it's end) derived from projects set in late 20's and early 30's. Fiat was not a monopolist (Alfa Romeo, Isotta Fraschini e Piaggio produced radials), but the A.74 was the best avaliable (not a monster of power, but small, lightweight and completely reliable under every condition) when the first generation of italian monoplane fighters was developed. The real mistake was to stop even the development of in-line engines that have already been set in 1933, with the only partial exception of Isotta Fraschini (who paid for the development of in-line engines, by almost disappearing from the market).

This is a table of italian engines until 8 september 1943. It's missing some engines. And the power output refers to takeoff. But i'm not sure for every engine...
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.
 
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.
 
The decision was to relay on radials, and, in the early '30s, it seemed not a wrong one. When the single alluminium cylinder cast tecnology was introduced for the radials, the power/weight ratio of radials, jumped beyond what could be achieved with in-line engines, and without having their side problems. In the early '30 the radials seemed the last frontier in Aero Engines developement, and only slowly the inlines regain the lost ground. Is revealing that several of the inlines that were used at the beginning of the war (and sometimes until it's end) derived from projects set in late 20's and early 30's. Fiat was not a monopolist (Alfa Romeo, Isotta Fraschini e Piaggio produced radials), but the A.74 was the best avaliable (not a monster of power, but small, lightweight and completely reliable under every condition) when the first generation of italian monoplane fighters was developed. The real mistake was to stop even the development of in-line engines that have already been set in 1933, with the only partial exception of Isotta Fraschini (who paid for the development of in-line engines, by almost disappearing from the market).
Did I mention that the same FIAT had a better engine (with a good compressor) to use as a base for further developments: the A.33. But they preferred to satisfy hierarchies and continue safe production. The hierarchies were wrong? It was better indulge them, to defend private interests of the FIAT!
The FIAT was not a monopoly in Italy?!? They produced without problems G.50! That was not the best of the possibilities. But not even the second or third choice! I remeber Reggiane Re.2000 and Caproni Vizzola F.5 (that the designer named Fabrizi, before he died, wanted to power it with the Asso XI). Then FIAT produced a biplane: the CR.42! And there was still a better biplane: the Caproni Ca.165!
The A.80 engine was one of the worst in existence, but it continued to be produced.
Some things happened in other areas. As in the production of tanks. The Ansaldo was owned by FIAT. The tank "Carro Celere Sahariano" (which was based on technology transferred from a BT-5 captured during the Spanish Civil War, as the M.11 tank is practically a Russian T.26) was only released to prevent a licensed production of a Czech tank!
Finally, the FIAT refused the production of an aircraft, in time of war, because it was not their project! And that was that!! Unfortunately I have to track down the source of this latest news. But I'm 100% sure!
And the A.74 wasn't the best best engine available. And infact nobody tell anything about Asso XI and its derivative, the L.121. This was the Caproni Ca.165 engine. It was proposed an improvement named Asso L.122. And, for me, it was not so difficult to reach the 31.1 CV/L necessary to the 1000 cv continuous power output at altitude. A number far below of all subsequent projects.
I read on a recent italian aircraft magazine that L.122 did not work. But I've never seen mentioned sources. And I believe that the sources simply do not exist. It is a rumor. And if anyone knows the sources you show me. In my opinion, the construction of the prototype never began.
In fact, in 1940-41 the Reggiane who had never invented engines, but only licensed products, it began a research on new engines. Among the various projects (of which it was made only the Re.103 RC50 I) there was a modernization of the Asso L.121. But then, although the project was complete, it was not realized.
The Piaggio P.XI had problems but continued its development into the P.XIX. The FIAT A.80 had many problems. And so other engines. But the IF L.121 Asso is a taboo! Perhaps because it is the crux of the matter.
 

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