Italian air force is indifferent on on the air-cooled engines?

[mack8]

Just a question regarding the Fiat A74 engine, i have in memory reading somewhere that the 960 HP emergecy power was otained with some kind of additional injection, methyl or ethyl or something like that. But looking through some stuff i have i can't find anything about this for now. Am i wrong and confusing this with something else? (one the reason i'm asking for this being that, if it was the case, perhaps this injection system can be added to other engines, inline or radial)

PS: I have found the following re the SM79, maybe this is what i was thinking of?
In 1942, the Alfa-Romeo 126 engines were equipped with an ethyl alcohol injection system that increased by 20 minutes. engine power from 780 to 900 hp sec., this gave a speed increase of 50 km / h. But the payment for this was a sharp decrease in the resource of motors, which were already in short supply.

 

[tomo pauk]

Just a question regarding the Fiat A74 engine, i have in memory reading somewhere that the 960 HP emergecy power was otained with some kind of additional injection, methyl or ethyl or something like that. But looking through some stuff i have i can't find anything about this for now. Am i wrong and confusing this with something else? (one the reason i'm asking for this being that, if it was the case, perhaps this injection system can be added to other engines, inline or radial)

Manual for the A.74 notes the 960 HP short term emergency power, but it does not mention any additional injection system.
The ADI systems are/were certainly viable thing to add to the existing engines, even though ADI systems were very rare in service anywhere in the world before Italian armistice.

PS: I have found the following re the SM79, maybe this is what i was thinking of?
In 1942, the Alfa-Romeo 126 engines were equipped with an ethyl alcohol injection system that increased by 20 minutes. engine power from 780 to 900 hp sec., this gave a speed increase of 50 km / h. But the payment for this was a sharp decrease in the resource of motors, which were already in short supply.

Very interesting. What is the source?

 

[mack8]

Re the SM79 boost system, it's off some site on the www, but i recall reading about this a while time back in some book dealing with the SM79, could have been an Osprey book, or maybe an italian book, but not sure yet.
PS: This is where the quote above comes from, but there are other sites, such as Warthunder etc.

Savoia-Marchetti S.M.79 Medium bomber and torpedo bomber - Italy

 

[tomo pauk]

Re the SM79 boost system, it's off some site on the www, but i recall reading about this a while time back in some book dealing with the SM79, could have been an Osprey book, or maybe an italian book, but not sure yet.
PS: This is where the quote above comes from, but there are other sites, such as Warthunder etc.

Savoia-Marchetti S.M.79 Medium bomber and torpedo bomber - Italy

Thank you again
Paging Vincenzo and D Deleted member 68059 - perhaps you people can shed some light wrt. ethyl alcohol use on Italian engines?

 

[mack8]

This may or may not be familiar to folks here, but on this page there is some very interesting italian engine info, mostly I-F, but also including production figures/orders from 1941 onwards.

Motori Isotta Fraschini

it.cultura.storia.militare.narkive.com

Note the paltry Isotta Fraschini engine production numbers 1941-44 of largely useless engines. Mostly due to the chronic inefficiency/corporate interests/Caproni's pigheadness that had them keep trying to shove useless engines such as Delta onto Regia Aeronautica. Since we are talking about inlines, if Mussolini's people would have been more forceful and got I-F to manufacture DB-601s under licence, looking at the figures for the other italian DB producing companies, even 1000 I-F manufactured RA-1000s would have been most useful. Even if Caproni would have insisted they be mounted on Caproni Gruppo planes, that could mean the order for 600 Re-2001s could have been actualy built. And if they managed to switch to the DB-605/RA-1050 in 1943 and build even a few hundred of them, then more of the gorgeous Re-2005 could be built as well. (i realize this goes against my original suggestion of building only radial Reggianes and leave inlines for Macchi and Fiat, but just exploring another scenario closer to OTL)

Also, don't take my word for it, but i might have read somewhere that when the DB-601 licence was bought in 1939, the government tried to get Fiat interested to build them, but Fiat was not interested. But again, if the goverment was more forceful, Fiat could have built RA-1000s as well, even another 1000 means Fiat could have built a few hundred of the good looking and fast G-50V (probably called G-51 or 52).

 

[z42]

BTW, did the Italian license produced DB 601/605 engines also suffer from the valve problems that plagued the Germans? Or did they have sufficient access to the critical alloy metals so they didn't need to skimp on the valves?

 

[tomo pauk]

BTW, did the Italian license produced DB 601/605 engines also suffer from the valve problems that plagued the Germans? Or did they have sufficient access to the critical alloy metals so they didn't need to skimp on the valves?

Italian data sheets of 1943 (as listed here, for example)show the max power of the DB 605A as 1250 HP at 5.7 km. Looking at the power graph, that is for 2600 rpm + 1.30 ata operation, ie. de-rated engines.
Italian DB 605s still have a problem with lubricating, that DB solved (copying Jumo solution?) in late 1943.

 

[rinkol]

'Indifferent' as in they don't make a push towards these in the 1930s, instead just say to the aero engines' companies something like: We will buy the ever better engines, provided you can make them?
How much the Italians are better (worse?) if eg. Fiat and Isotta-Fraschini continue to develop the liquid-cooled engines instead of making the air cooled detour?

Not saying it is an insta-win for the Italians in the ww2, of course.

One thing that struck me was that both Issotta-Fraschini and Piaggio licensed the Gnome Rhone K-14, an engine with limited development potential, partly due to the lack of a center bearing. The former produced very few of these engines and might have done better by licensing the DB engines or even developing a monobloc version of its existing liquid cooled engines.

 

[Shortround6]

One thing that struck me was that both Issotta-Fraschini and Piaggio licensed the Gnome Rhone K-14, an engine with limited development potential, partly due to the lack of a center bearing. The former produced very few of these engines and might have done better by licensing the DB engines or even developing a monobloc version of its existing liquid cooled engines.

Partial excuse is when did they license the G-R engine?
two row radials with a center bearing were about as rare as real Griffon in the early 30s.

Mono block engines also depend on the state of the art of your casting foundries. Just because you can make a straight 8 car engine does not mean you can make V-12 aircraft engines.

 

[mack8]

Certainly the to date inline specific Isotta Fraschini would have been far better served building DB engines of whatever variety. Piaggio could still stick with radials, at least they built some useful, if unreliable engines based on the K-14 tech. But I-F didn't even built that, Asso stopped being used and the Delta was a disaster and waste of time. Even DB-600s would have been a far better investment, if the licence can be bought early enough.

 

[Shortround6]

Even DB-600s would have been a far better investment, if the licence can be bought early enough.

Again, this assumes that Italian industry is up to the job.
You can go back to carburetors if fuel injection is too difficult.
However changing the rod bearings gets a little more fundamental.

I believe the main bearings were plain bearings while the rod bearings were roller bearings, three rows of rollers in each rod assembly.
The 605 went to plain bearings?

Now the saying among engine designers of the time was you use roller bearings when you don't trust your plain bearings (they won't do the job).
Bristol of England imported roller bearings by the score of tons from Sweden during WW II for Hercules production (mostly by converted MTBs) so this is not a simple solution.
Germans found a way but if you are expecting the Italians to beat the Germans timewise in re-engineering the DB 601 engine it may not work out well.

And again, this is for engines you are hoping to make in scores per month, not race car engines of a handful per year.

 

[z42]

I've been trying to understand the sorry state of Italian air force equipment in WWII and what were the factors behind it during the interwar years, and I came upon this interesting blog post that seems to answer it to a large extent: The Regia Aeronautica: Another Victim of Mussolini's Regime

This blog post places the blame largely on the poor industrial policy of the Mussolini regime, par for the course for fascist dictatorships one might even say. Mussolini was deathly afraid of labor unrest; indeed it was during fighting with communists during a previous period of labor unrest that he was able to gain power, so he was obviously afraid the same might happen to him. This resulted in very expensive and poor equipment, as there was no real competition, as the goal was more to keep the factory workers employed rather than selecting the best possible aircraft for the air force. The industry was organized in large vertically integrated conglomerates, with a strong incentive to use their own engines in their aircraft, rather than selecting the best available engine between multiple offers. And due to a policy of autarchy, there was essentially no competition from foreign suppliers either. Due to these factors, there was also little incentive for the industry to spend money on R&D; why bother when you had a guaranteed market anyway?

Considering this, my previous statement in this thread maybe needs some added nuance:

Considering the size of the Italian aero engine R&D and production it might have made sense to concentrate on one kind of engine. But it seems they made the wrong choice, in that Italy was making ok-ish inlines when development was stopped, and was behind in radials?

The above blog post makes the case that by the time this decision was made (1933) Italy was also behind in inline engines. So something drastic needed to be done anyway, and while I still think concentrating on one type of engine was the correct thing to do given the size of the Italian engine R&D ecosystem, perhaps which way the choice ultimately went wasn't fatal by itself.

So what should Italy have done, assuming we can ignore Il Duce's fear of labor unrest? Maybe opposite of what this thread ostensibly is about, that is, be even more prescriptive. Say,

1. The coin flip says to choose radials, as historically.
2. The state gives a "royal warrant" to two companies, saying all state aircraft must be powered by engines from these two companies. Two to ensure some competition between them. Shower them with R&D money to develop a couple of good engines each rather than a plethora of mediocre ones.
3. Split up the vertically integrated conglomerates, so that aircraft designers have an incentive to choose the best engine (from the above two companies) rather than being forced to use the in-house one.
4. State does aircraft tendering where the best offering is chosen.

 

[Shortround6]

Part of the problem was that the Italian industrial base was so small.
Even if you put all the small pieces of a small pie together you still have a small pie.

The export of aircraft during the 30s actually doesn't amount to a whole lot in the terms of WW II production.

"Excluding the aircraft sold or given to Franco's Nationalists, modern fighter and bomber exports from 1937 to 1940 included 79× Savoia-Marchetti SM.79s, 82× Fiat BR.20s, 171× Fiat CR.42s, 35× Fiat G.50s, and 130× Reggiane Re.2000s."
161 multi engine aircraft and 335 single engine fighters in 3-4 years.
In 1940 the US built 1685 single engine fighters of all types. Curtiss was building 114 to 168 fighters per month in last 7 months of 1940.

Even if the Italians had kept all of those aircraft at home (and given up the cash/raw materials) that only equaled 2 months of 1940 production to either the US or Britain.
And 1937 aircraft were death traps in 1940, let alone 1941.

"Even as Mussolini looked for a way to bring Italy into the war in spring 1940, the desperate need for hard currency and strategic goods made him initially approve export orders of 12 Macchi C.200 fighters to Denmark and, shockingly, 300× Caproni Ca. 313 reconnaissance bombers, 100× Ca. 311 trainers, and 300× Re.2000 fighters to Britain"
Ca.311 "trainer"

Box art. Basically as super Avro Anson. 470-500hp engines, wooden wings and steel tube and mostly fabric fuselage, not much light alloy being exported to the future enemy
CA 313

Basically the same plane with over 700hp air cooled V-12s.
Basically a non-strategic Blenheim a lot less alloy and engines of lower power than a Bristol Mercury.
Re.2000 fighter

A lot of P-35 influence. Might have been better than MC 200?
Most of the early ones went to Sweden and Hungary.

And we are back to the engines.
The Piaggio P.XI R.C.40 was developed from the Gnome Rhone 14K which used a two bearing crankshaft, but you got a Hercules sized engine for hundreds of pounds less. Where the cross-over point to go to a 3 bearing version is somewhat debatable. If you have 87 octane fuel and can't use much boost the 3 bearing crank is useful but less so than if you have better fuel. You also have to figure out how to make deeper, thinner, more closely spaced fins if you want to make more power (higher rpm means higher heat rejection) The Soviet M-88 came from the same 14K base.
But the Piaggio P.XI was several hundred pounds heavier than the Fiat A.74 and about 80mm bigger in diameter. Please note that the Piaggio was about the same weight as P&W R-1830 with a single speed supercharger used in the P-36.
The Italian engines may not have had the reliability but that may be due to a number of things, like poor materials.

Basically Italy had less industrial capacity than Canada and was trying to play world power.
Il Duce's mouth was writing checks his body (industry) couldn't cash.

 

[z42]

Basically Italy had less industrial capacity than Canada and was trying to play world power.
Il Duce's mouth was writing checks his body (industry) couldn't cash.

I don't think there's any realistic path to them achieving victory in the war, whatever they do. I'm just arguing they could have done considerably better than they did with the resources they had.

Looking at GDP, WWII: annual GDP of largest economies 1938-1945 | Statista , Italy during the war was about half the size of the UK, and about 70% the size of Japan. So yes, the smallest of the three major axis powers, but it wasn't a midget either. They just punched below their weight.

 

[z42]

Part of the problem was that the Italian industrial base was so small.
Even if you put all the small pieces of a small pie together you still have a small pie.

The export of aircraft during the 30s actually doesn't amount to a whole lot in the terms of WW II production.

"Excluding the aircraft sold or given to Franco's Nationalists, modern fighter and bomber exports from 1937 to 1940 included 79× Savoia-Marchetti SM.79s, 82× Fiat BR.20s, 171× Fiat CR.42s, 35× Fiat G.50s, and 130× Reggiane Re.2000s."
161 multi engine aircraft and 335 single engine fighters in 3-4 years.
In 1940 the US built 1685 single engine fighters of all types. Curtiss was building 114 to 168 fighters per month in last 7 months of 1940.

Even if the Italians had kept all of those aircraft at home (and given up the cash/raw materials) that only equaled 2 months of 1940 production to either the US or Britain.
And 1937 aircraft were death traps in 1940, let alone 1941.

If we look at the table of aircraft the Italians used during the conflict List of Regia Aeronautica aircraft used in World War II - Wikipedia , the highest numbers go to the Fiat CR 42 at 1551. And that's a frickin biplane. That's quite, err, pitiful.

 

[Shortround6]

I don't think there's any realistic path to them achieving victory in the war, whatever they do. I'm just arguing they could have done considerably better than they did with the resources they had.

Looking at GDP, WWII: annual GDP of largest economies 1938-1945 | Statista , Italy during the war was about half the size of the UK, and about 70% the size of Japan. So yes, the smallest of the three major axis powers, but it wasn't a midget either. They just punched below their weight.

GDP is useful but it can be misleading. For instance GDP includes agricultural output, important and useful but not very important to modern warfare. You can feed the troops. You can't give them guns, shells, ships. airplanes etc. Some Italian companies could make good steel, but they needed to import both iron and coal. Germany had to agree to ship large quantites of coal to Italy to get them to actually join the war. Italy had been getting a lot of their coal from Britain up until early or mid 1940.

India in the late 30s and during a lot of WW II had sizable GDP. What they didn't have was much surplus industry, steel or vehicle manufacturing.

Better planning could have increased Italian production. But the change in the overall scheme of things was not going to change much.
The Navy had starved the Army of resources. The Italian army was running on WW I leftovers. They had some good designs (and some poor ones) but building around 200 75mm field guns in the late 30s and using just about all WW I leftovers?

Italy was short of Aluminum, which is why they used wood in so many of their aircraft designs.
Using one or two different radials would be more efficient than building 6 or more different radials but if you don't have the steel for crankshafts and cylinder barrels?
Or good bearings?

The US and Britain made some major changes in bearing technology and lubrication. Other countries may not have been able to follow due to material shortages. If Italy didn't have it they were relying on Germany to give it to them. Or Germany to allow Austria, Rumania, Finland or whoever to ship it to Italy after Germany got what they wanted.

 

[Dogwalker]

Note the paltry Isotta Fraschini engine production numbers 1941-44 of largely useless engines. Mostly due to the chronic inefficiency/corporate interests/Caproni's pigheadness that had them keep trying to shove useless engines such as Delta onto Regia Aeronautica.

Mostly due to the fact that, on March 20 1940, Gen. Francesco Pricolo, freshly nominated Chief of staff of the Regia Aeronautica, cancelled the orders for the Isotta Fraschini Asso L.121 RC.40 engine (960hp at 4000m) and didn't commission the construction of Asso L.122 RC.50 (1055 hp at 5000m) that Isotta Fraschini proposed (then for the biplane Ca.175, evolution of the Ca.165) since 1938.
That way killing the only line of world-class liquid cooled inlines Italy had at the start of WWII.
Likely because the licence to manufacture the DB601 was obtained by Alfa Romeo in Nov. 1939, so Pricolo thought a better engine (that also had the inverted V configuration, that the Regia preferred), was already on the way.
Unfortunately, serial manufacturing of Alfa Romeo DB601, started only in late 1941. More than 1 and half years after that decision.
At the same time, Pricolo confirmed the orders for the Delta engines. Because, despite the power gap with the Asso, those were inverted V, and seemed apt for other uses (reconnaissance aircrafts, light bombers...).
That's why, when the insufficient production of DB601 became evident, in summer 1942 Reggiane Technicians had to try shoving a 840hp Delta IV into the fuselage of a Re.2001, when a better engine was available 4 years before (and one better than the DB601Aa would have probably been well available in 1942, had the L.122 been ordered).

 

[Dogwalker]

Italy was short of Aluminum, which is why they used wood in so many of their aircraft designs.

No.
Italy had never been short of aluminium. In the '30s, thanks to the mines in Istria, Italy was one of the main world producer of aluminium (it produced more than the Soviet Union, IE), and aluminium was infact considered an "autarchic" material. The MG151-20 and Stuka that Italy acquired from Germany, had been paid in aluminium alloys.
What Italy was short of were alloy elements for steel (chrome, molibdenum, etc.).
Italy used wood in many aircrafts because that was a transition period, and wood was the material the designers and the workforce were used to work with.

 

[Dogwalker]

Using one or two different radials would be more efficient than building 6 or more different radials but if you don't have the steel for crankshafts and cylinder barrels?
Or good bearings?

It's a question of scale. It's true that Italy was lacking alloy materials for steel, but, during the war, it built hundreds of thousands tons of ships. In the grand scheme of things, the steel required to build some thousands engines is scarcely relevant.

 

[Dogwalker]

Italian data sheets of 1943 (as listed here, for example)show the max power of the DB 605A as 1250 HP at 5.7 km. Looking at the power graph, that is for 2600 rpm + 1.30 ata operation, ie. de-rated engines.
Italian DB 605s still have a problem with lubricating, that DB solved (copying Jumo solution?) in late 1943.

Italian data sheets are simply identical to the German ones for the DB601A, that was the engine they acquired the licence of. Kurfürst - DB 601, 603, 605 datasheets - DB 605 A
The Germans cleared the 2800 rpm 1.42 ata operation only in august/september 1943, so when Italy exits the war, so it's unlikely FIAT ever did before the armistice. However, in the same publication, the FIAT A74 is rated at 840 hp at 3800m, that we know is not the max power. Simply the publication uses the "normal" power, and not power ratings that could be kept only for few minutes.