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Infact I made a comment about the chart posted, not about you. Sorry if you have taken it personally.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
I know, and personally I like the Zeta very much. Personally I believe that the most part of It's problems, as for that of the more powerful versions of the Delta, were more due to the installation on a particular aircraft (for such an engine, dimensioning and positioning of air intakes and exhausts required a more careful work than of the positioning of a NACA cowling, or a radiator, in conventional engines), that to the engine itself. But the fact remains. The Zeta still had several problems in autumn 1943. The P.XV didn't had the same problems, and was a world class engine in 1943, demonstrating that it was possible to do them, even in Italy (harder it was to prepare a mass production, the real problem in Italy was manufacturing, not of designing).About Zeta and its problems, every engine needs a development period.
I don't consider it, cause it means very little. We are not talking about a race in which there are displacement limits.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).
...
You, Dogwalker, don't consider the difference necessarily due to the displacement of the engines.
I said that cause the AS.5 and AS.6 are exclusively race engines, whose only spin-off was an underpowered engine, that has not been further developed (also the Jumo 210 was underpowered, but it was evolved). In the same years were set the projects for the Allison V-1710, DB 600 and RR Merlin. You don't see a lack of planning in Italian inlines in those years?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.
I am very sorry that you're tired, but frankly I did not understand what you're complaining to me.Excuse me. I'm tired of rumors...
Excuse me, Sibboh, but, speaking of "unsupported rumors", if the FIAT was the manufacturer of both the A.30 (projected evolution A.33) and the A.74 (projected evolution, A.76), Why choose radials means "defending private interests of the FIAT"? Indeed, in the area of in-line engines the only competitor for the FIAT was the Isotta Fraschini, in the area of radial, there were also Alfa Romeo and Piaggio, the competition was harder.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!
No, it was'nt ,even if the question is written with many marks. There was competition for both the engine and in the aircrafts. Fiat produced the G.50, and wasn't able to impose a good aircraft as the CR.25 over the terrible Ba.88. Mistakes were certainly made in the choice of Italian aircrafts first than the beginning of the war, as in the aircrafts of other nations for that matter (it's hard to say that the Defiant or the Fulmar had been the best choices available, and even the USA, in 1940, had in service some not really very successful aircraft), but is not that all arise from the fact that FIAT was protected politically. It was, but that's not an explanation for all.The FIAT was not a monopoly in Italy?!?
I know the Asso XI, and I agree it would be a better choice, in general, than the A .74, but I was talking about radials, since radials were the choice of the Air Force.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.
Remember that Reggiane was part of the Caproni group, the owner of IF. There is nothing strange for their experimental section to try to improve IF products. It's the kind of the relationship that exists between the HRC and Honda. Visually, even the Re.103 seems an inverted V IF W18 equipped with a DB-like compressor.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.
Agree on that. In theory, it would be sufficient to equip an Asso XI RC40 with a compressor able to produce, at 4000m, the 841mm hg the Asso XI RC15 had at 1500m (normal operating pressure, not overboost), and it will produce more than 1000hp at 2400rpm at 4000m only for the lower counterpressure at the exhaust.for me, it was not so difficult to reach the 31.1 CV/L necessary to the 1000 cv continuous power output at altitude
Yes, there are different errors in the chart. But other data are interesting, like the P.XIX RC.50-2V that supplied, if this is correct, 1250 cv at takeoff, when the P.XIX RC.45 supplied only 1100 cv.Dogwalker said:the P.XIX was definitely service in September 1943, and, in the "experimental" section, are listed engines already widely tested, for which the Air Force had ordered the production of thousands of copies, with engines that could have been be set just on paper
Yes, i agree. But i wanted to tell another thing. The italian errors were to discard any particular engines instead of developing them, keeping certain inefficient projects (i refer in particular to A.80), and engaging in challenging projects in a time of emergency, when it was more useful to make efficient and functional things. The italians new projects were a V16 (possible torsional vibrations with a so long and complex crankshaft), X24 Zeta and Sigma (complex solution and cooling problems in an inline aircooled engine), etc...Dogwalker said:I know, and personally I like the Zeta very much. Personally I believe that the most part of It's problems, as for that of the more powerful versions of the Delta, were more due to the installation on a particular aircraft (for such an engine, dimensioning and positioning of air intakes and exhausts required a more careful work than of the positioning of a NACA cowling, or a radiator, in conventional engines), that to the engine itself. But the fact remains. The Zeta still had several problems in autumn 1943. The P.XV didn't had the same problems, and was a world class engine in 1943, demonstrating that it was possible to do them, even in Italy (harder it was to prepare a mass production, the real problem in Italy was manufacturing, not of designing).
Dogwalker said:I don't consider it, cause it means very little. We are not talking about a race in which there are displacement limits.
It's natural for the smaller displacement engines to have an higher specific output, but, on air, what count more is the hp output, then the hp/weight ratio, then the hp/dm2 (a lot less than the previous ones, since the drag of the engine is only part of that of the entire aircraft, and, for the inlines, the drag of the radiator is rarely taken into account). For example, if (simplifying) a Piaggio P.XII has the same power, the same weight and the same diameter of a Bristol Hercules, what does it matter if the first is a 53l engine that obtain the same power of the second (a 39l one) functioning at lower rpm? They are engines of the same class. The efficiency of an aircraft engine is measured in this, and in the consumption, not in the specific power. The specific power is useless.
The Fiat A.30 prototype ran for the first time in 1930 (or 1929 ?).Dogwalker said:I said that cause the AS.5 and AS.6 are exclusively race engines, whose only spin-off was an underpowered engine, that has not been further developed (also the Jumo 210 was underpowered, but it was evolved). In the same years were set the projects for the Allison V-1710, DB 600 and RR Merlin. You don't see a lack of planning in Italian inlines in those years?
There are no doubts that the A.74 was an overall better engine than the A.30, and, again, the power/displacement ratio has little to do with it.
Excuse me, Sibboh, but, speaking of "unsupported rumors", if the FIAT was the manufacturer of both the A.30 (projected evolution A.33) and the A.74 (projected evolution, A.76), Why choose radials means "defending private interests of the FIAT"? Indeed, in the area of in-line engines the only competitor for the FIAT was the Isotta Fraschini, in the area of radial, there were also Alfa Romeo and Piaggio, the competition was harder.
Fiat produced 778 G.50 (one of the most produced italian fighter), circa 1800 CR.42 (the most produced italian fighter). FIAT was the most important italian industry.Dogwalker said:No, it was'nt ,even if the question is written with many marks. There was competition for both the engine and in the aircrafts. Fiat produced the G.50, and wasn't able to impose a good aircraft as the CR.25 over the terrible Ba.88. Mistakes were certainly made in the choice of Italian aircrafts first than the beginning of the war, as in the aircrafts of other nations for that matter (it's hard to say that the Defiant or the Fulmar had been the best choices available, and even the USA, in 1940, had in service some not really very successful aircraft), but is not that all arise from the fact that FIAT was protected politically. It was, but that's not an explanation for all.
And infact it was a bad choice. One of many bad choices!Dogwalker said:I know the Asso XI, and I agree it would be a better choice, in general, than the A .74, but I was talking about radials, since radials were the choice of the Air Force.
Dogwalker said:Remember that Reggiane was part of the Caproni group, the owner of IF. There is nothing strange for their experimental section to try to improve IF products. It's the kind of the relationship that exists between the HRC and Honda. Visually, even the Re.103 seems an inverted V IF W18 equipped with a DB-like compressor.
Dogwalker said:Agree on that. In theory, it would be sufficient to equip an Asso XI RC40 with a compressor able to produce, at 4000m, the 841mm hg the Asso XI RC15 had at 1500m (normal operating pressure, not overboost), and it will produce more than 1000hp at 2400rpm at 4000m only for the lower counterpressure at the exhaust.
But IF developed more advanced compressors for the Delta and the Zeta, not for the Asso.
Cause, after the production licence of the DB601 was aquired (by the Alfa Romeo in this case, not the Fiat), for the Asso XI / L121 there was no more possibilities on the market (remember that, even at the same power output level, the Regia Aeronautica preferred inverted V engines for fighters, Infact they forced FIAT to invert the V of the A.38 ) the developement would have had to be made before. Also an IF L.122 that would produce, say, 1200 hp, in 1941, would have been useless with the DB601 already available.
Not only the P.XV would have been good for a fighter, but even It's predecessor, the P:XII would have.P.XV was good for bombers. But a fighter was projected at the end of 1942 (the interesting Piaggio P.32). Too late. This engine had the same P.XII dimensions. The diameter was 1410 mm. A big encumbrance! P.XI diameter was 1328 mm, P.XIX diameter 1274 mm, Fiat A.74 diameter 1195 mm. Obviously a high frontal surface was a serious aerodynamical obstacle. Particularly with a reduced power. Also the ratio between power and the front surface must be at least good.
And how much the fuselage of a Tunderbolt or an Hellcat was wider than the engine? Those aircrafts could easily accommodate a wider engine than the R-2800. Only the Corsair took real advantage of the limited frontal surface of the R-2800.The R-2800 diameter was 1341 mm
Really?RR Merlin had the lowest displacement, but was very powerful. Infact his ratio between the power and the displacement is the best. Yes, it didn't matter if there was a powerful engine. But bigger engine is heavier engine.
Only that the Kestrel run for the first time in 1927, and the Fiat A.33 run in 1935. In 1935 RR was preparing the Merlin and the Griffon. I'm still seeing a lack in planning on italians inlines in the years from 1929 to 1937 more than after.Marchi wrote (page 88): "Il nuovo motore è dotato di un poderoso originale e complicato carburatore con regolazione automatica in funzione della temperatura e della pressione variabili con la quota. ... Ne riuscì un motore eccellente; certamente uno dei migliori e tecnicamente avanzati tra i motori realizzati dalla Fiat e che fu l'ultimo 12V. L'A.33 era confrontabile per caratteristiche, prestazioni ed affidabilità con il Kestrel della R-R."
Sure? The A.74 supercharger was still able to give 890mm hg at 3000m. The Asso XI RC.40 supercharger can give more than 822mm hg only up to 2000m. Is not than the supercharger isn't able to give the boost, is that the engine is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes.Isotta Fraschini Asso XI was born in 1934. It had a better supercharger than A.74 and A.80 (And it took a little ... ).
And so?Fiat produced 778 G.50 (one of the most produced italian fighter) ... Breda produced only 149 Ba.88.
Could be, but, since the Alfa Romeo acquired the production licence of the DB601 at the end of 1939, the choice of using it was pretty obvious.At the beginning of 1940 there were rumors of a possible installation of the L.121 on one of the prototypes Macchi C.201
The L.121 surely run. It was the engine of the Ca.165 and of the Caproni-Campini N.1 for example. It was hologated for aircraft use, only that the Regia didn' want it on fighters.Yes, but if Asso L.121 (and projected L.122) didn't run...
Surely they had the knowledge, but they didn't apply it on their most powerful products, as, at the time the DB601 licence was acquired, the Delta didn't produced more than 770hp. Surely not bad for a 27l, two valves, air cooled engine, but still only 770 hp.IF had an engine of this time before DB601Aa ran for the first time: the Delta (first ran in 1936-37). So they had the knowledge, if necessary.
A) Only that the Kestrel run for the first time in 1927, and the Fiat A.33 run in 1935. In 1935 RR was preparing the Merlin and the Griffon. I'm still seeing a lack in planning on italians inlines in the years from 1929 to 1937 more than after.
B) Sure? The A.74 supercharger was still able to give 890mm hg at 3000m. The Asso XI RC.40 supercharger can give more than 822mm hg only up to 2000m. Is not than the supercharger isn't able to give the boost, is that the engine is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes.
Another not developed prototype. One of many. Talking about "lack of planning".But you forget the A.30RC (this had supercharger). It ran for the first time in the 1933. And we don't know its performances. Unfortunately it was only a prototype.
So they were happy to have, as the epitome of Fiat inline products, an engine competitive whit one for which the RR was already preparing the two next stage of evolution. I'm still seeing a lack in planning on italians inlines in the years from 1929 to 1937 more than after.And hierarchies were happy to have a good engine.
Who doubt? I wrote "lack of planning", not "lack of knowledge". But not having planned the developements in the years 1929-1937, led to the lack of knowledge after, when the A.38 had to be built, since is difficult to double the power of your main inline engine without intermediate steps.But the fact remains that the technicians had the appropriate knowledge.
Yes. Did you read the manual? Asso XI RC.40's supercharger was able to give more than 822 mm hg (overboost) only up to 2000m, while the A.74 supercharger was able to give 890mm hg at least up to 3000m.Do you see the small circles in the Asso XI RC40 engine chart?
The A.74 is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes. We were talking about an an alleged inferiority of the supercharger of the A.74, remember? But: "Is not than the supercharger isn't able to give the boost, is that the engine is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes", but if the engine demanded more pressure, the compressor of the A.74 was perfectly capable of supercharge it.But really do you think that IF Asso XI was practically unsupercharged?
Cause is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes.A.74RC38 used 890 mmHg only in takeoff and emergency conditions (per pochi minuti/for a few minutes).
Yes, there was a lack of planning in all italian union history. I told that there were problems, during 1930s, due to political incompetence, to clientelism and to contrasts between different potentates (political, industrial...), that were part and cause of the "lack of planning".Dogwalker said:Another not developed prototype. One of many. Talking about "lack of planning".
Infact i didn't tell "lack of plannings" when i first spoke about italian problems (4-28-2013 02:28), but i told: "There was a lack of improvements during the 1937-1940 period.". Improvements. During the 1929 to 1937 period at least there were a bit of improvements. Not plannings. Plannings is a political problem. And on this, I think, we fully agree.Dogwalker said:So they were happy to have, as the epitome of Fiat inline products, an engine competitive whit one for which the RR was already preparing the two next stage of evolution. I'm still seeing a lack in planning on italians inlines in the years from 1929 to 1937 more than after.
In this we are not quite agree. Certainly the lack of planning has created problems. You believe that there has been no development between 1929 and 1937. So that the characteristics have remained steadfast and therefore the same. I do not see this. I see an improvement of between 1929 and 1937. (I've created a table with data to prove it. Data are put into chronological order. Features checked and I entered a small bibliography.) Instead I see the lack of improvement of engine performance at least for the period 1937-1940, when really the characteristics were the same (the example of A.74 for me may suffice: 1935-1942!). Certainly not doing proper research in previous years and had not improved by degrees existing engines has created many problems. And that's why I said from the beginning. But I do not think there were large gaps of knowledge when the A.38 was designed and built. This is the difference between what I think and what you think.Dogwalker said:Who doubt? I wrote "lack of planning", not "lack of knowledge". But not having planned the developements in the years 1929-1937, led to the lack of knowledge after, when the A.38 had to be built, since is difficult to double the power of your main inline engine without intermediate steps.
Yes, i read manual. So you have to give me the page, because i don't see it. I see only a problem about takeoff in plateaus up to 2000 m. But takeoff, not overboost at altitude. The power chart tell me other.Dogwalker said:Yes. Did you read the manual? Asso XI RC.40's supercharger was able to give more than 822 mm hg (overboost) only up to 2000m, while the A.74 supercharger was able to give 890mm hg at least up to 3000m.
Atmospheric pressure is 760 mmHg. 790 mmHg or 822 mmHg aren't atmospheric pressure. DB 601 and DB 605 give a normal continuous power output at 1,15 ata, 846 mmHg: is it more or less at atmospheric pressure? Kestrel IS/IIS/IIIS only 734 mmHg, really less than atmospheric pressure.Dogwalker said:The A.74 is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes. We were talking about an an alleged inferiority of the supercharger of the A.74, remember? But: "Is not than the supercharger isn't able to give the boost, is that the engine is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes", but if the engine demanded more pressure, the compressor of the A.74 was perfectly capable of supercharge it.
Grazie, non l'avevo capito. Scusa il sarcasmo.Dogwalker said:Cause is designed to function more or less at atmosferic pressure, and can be supercharged only for few minutes.
During the 1937-1940 period the power output of the Italian radials grew up of more than 50%, and were set the path for further developements.Infact i didn't tell "lack of plannings" when i first spoke about italian problems (4-28-2013 02:28), but i told: "There was a lack of improvements during the 1937-1940 period.". Improvements. During the 1929 to 1937 period at least there were a bit of improvements.
They had to do things in a hurry, at the last moment, cause they didn't do it before, while Allison, DB and RR were doing it. And the developement process of their main products (V-1710, DB600 and Merlin) were set from the late '20s to the early '30s.Instead, I believe that the problems were not solved because they tried to do things in a hurry and at the last moment!
On that page is clearly stated that the lever that manually open the intake valve of the supercharger, over 2000m is useless, since the automatic pressure control had already opened the valve more than the lever can do. If you can find other overboost commands in the manual, you have to tell me were they are. The only one listed, isn't able to give an overboost over 2000m.Yes, i read manual. So you have to give me the page, because i don't see it. I see only a problem about takeoff in plateaus up to 2000 m. But takeoff, not overboost at altitude. The power chart tell me other.
Are you that complained of the low working pressure of the A .74, blaming the supercharger, not me. I said that the supercharger was able to give more pressure, if required, and the manual shows it, but the engine isn't designed to require it.What is the boundary to overcome the "more or less at atmospheric pressure"?
Thank you very much, these are really great news. So the supercharger was able to give an overboost to the A.74, if required, or not? So, if the normal operating pressure was lover, is the fault of the supercharger, or is due to the features of the engine?If you see the engine power charts about different engines from all the countries, all had time limitations in takeoff and emergency.
During the 1937-1940 period the power output of the Italian radials grew up of more than 50%, and were set the path for further developements.
Italian inlines produced more than 1000hp already in the '20s, but the path, from 1929 to 1937, was to continue to refine a 600hp engine without plans to go beyond it. Yes, i see a lack of improvements too.
On that page is clearly stated that the lever that manually open the intake valve of the supercharger, over 2000m is useless, since the automatic pressure control had already opened the valve more than the lever can do. If you can find other overboost commands in the manual, you have to tell me were they are. The only one listed, isn't able to give an overboost over 2000m.