Italian Carrier Aircraft

[ThomasP]

Possibly, the best engine for an Italian carrier capable TSR/TB/Strike aircraft would be a variant of the Isotta-Fraschini W18-cylinder Asso series. By the late-1930s the engine was developing upto 1200 BHP. From what I have read it was a reliable and maintainable engine. In the early-1930s the 750 BHP variant was used in the S.55 flying boat and in the Ca.111 reconnaissance plane, while the 1000 BHP variant was used to power the Ca.90 bomber.

 

[nuuumannn]

It was the fall of France that poked the unforeseen hole in the perfectly reasonable logic. France was to be the principal counter to Italian activity and who would have expected the Germans to be able to operate out of airfields in western and southern France? Let alone Italy with no French support, but rather French bases in Syria being used by the Luftwaffe and French bombers bombIng Gibraltar.

That's exactly my point, no one foresaw that, heck not even the Germans expected France to fall as quickly as it did. Their hubris over it and subsequent invasions of Norway led them to belive their own hype and launch a failed attempt at subduing Britain. Without all this, perhaps British military planners might not have discovered the weakness we can so obviously see with the lens of hindsight.

 

[nuuumannn]

On a wee side note, in a book about the Fiat G.55 I have it states that the firm was asked to investigate a carrier based version of it, how far it got is not mentioned, nor are there any pictures. I'm away from home right now so can't provide anymore info.

 

[don4331]

Continuing my vendetta against drop tanks:

In early 30s, refineries were producing about 25% of what they would call gasoline via 1st run distillation. and that "gasoline" would have had an "octane" rating between 55 and 70. This "natural" gasoline would have been about 30% isopentane aka methylbutane. Isopentane is actually a pretty good fuel - octane rating of about 92 and thanks to the one triple carbon bond good energy density.

So, in WWI when we pour this natural gasoline into the upper wing tank and let gravity feed the carburetor, the engine runs fine up to the ~14k' level that humans without pressurization/oxygen can function at. Even during inter war period, when we move to fuselage fuel tanks feeding via gravity to an engine mounted pump, everything works pretty good. (Technically, it worked so well that automobiles into the 70s used this method).

But isopentane has one drawback - it boils at approximately 30°C at sea level. And that temperature decreases as you increase altitude (air pressure).

So, when you put a drop tank at end of a long pipe on the wing, and attempting to suck (lower pressure to initiate flow) petrol from the tank to the engine, the isopentane in the fuel vaporizes and you get nothing but a few vapours/ Worse, your fuel pump wasn't designed to be self priming so even when you switch back to the main tank the engine doesn't get fuel and restart. The idea is shelved as impractical.

Fast forward to very late 30s and refineries are no longer able to meet demands for gasoline with just 1st run distillation. And consumers are much fussier about the product they are receiving - they want 87 octane or better, they want their airplanes to be able to fly to 25k' or more without fuel boiling off and have fancy measuring equipment to ensure they are getting what they pay for. So, the refineries are using catalyst cracking process to make octane - specifically the 2,2,4 - trimethylpentane molecule which has a boiling point of 100°C for 90% of the product and very little of anything else for the remainder of the fuel.

Our engines are also now supercharged, so we can bleed a little compressed air off (or just add an air pump or steal some pressurized exhaust gas) and run a second line to our fuel tank(s) and keep the gasoline from boiling. (Pressurized air is also used to keep magnetos from shorting out).

Someone revisits the technology of drop tank and what 5 years before didn't work at all, now works like a charm. And there is stampede to equip planes, especially fighter with this new feature (despite it not being the perfect solution - but very little in engineer doesn't have some trade off).

So, it isn't an expensive bathtub toy versus expensive tanks, it's a viable technology to science fiction one in early/mid 30s when RM should have been building a CV.

 

[Shortround6]

Possibly, the best engine for an Italian carrier capable TSR/TB/Strike aircraft would be a variant of the Isotta-Fraschini W18-cylinder Asso series. By the late-1930s the engine was developing upto 1200 BHP. From what I have read it was a reliable and maintainable engine. In the early-1930s the 750 BHP variant was used in the S.55 flying boat and in the Ca.111 reconnaissance plane, while the 1000 BHP variant was used to power the Ca.90 bomber.

Problem with an 18 cylinder W engine is that they are somewhat on the heavy side.
The Asso gained quite a bit of weight as the years went on the the engine was modified to give more power.

By the time they got it to give 1200hp it weighed 2100lbs. That doesn't include water or radiator/s.

 

[Shortround6]

Continuing my vendetta against drop tanks:

In early 30s, refineries were producing about 25% of what they would call gasoline via 1st run distillation. and that "gasoline" would have had an "octane" rating between 55 and 70. This "natural" gasoline would have been about 30% isopentane aka methylbutane. Isopentane is actually a pretty good fuel - octane rating of about 92 and thanks to the one triple carbon bond good energy density.

So, in WWI when we pour this natural gasoline into the upper wing tank and let gravity feed the carburetor, the engine runs fine up to the ~14k' level that humans without pressurization/oxygen can function at. Even during inter war period, when we move to fuselage fuel tanks feeding via gravity to an engine mounted pump, everything works pretty good. (Technically, it worked so well that automobiles into the 70s used this method).

But isopentane has one drawback - it boils at approximately 30°C at sea level. And that temperature decreases as you increase altitude (air pressure).

So, when you put a drop tank at end of a long pipe on the wing, and attempting to suck (lower pressure to initiate flow) petrol from the tank to the engine, the isopentane in the fuel vaporizes and you get nothing but a few vapours/ Worse, your fuel pump wasn't designed to be self priming so even when you switch back to the main tank the engine doesn't get fuel and restart. The idea is shelved as impractical.

Fast forward to very late 30s and refineries are no longer able to meet demands for gasoline with just 1st run distillation. And consumers are much fussier about the product they are receiving - they want 87 octane or better, they want their airplanes to be able to fly to 25k' or more without fuel boiling off and have fancy measuring equipment to ensure they are getting what they pay for. So, the refineries are using catalyst cracking process to make octane - specifically the 2,2,4 - trimethylpentane molecule which has a boiling point of 100°C for 90% of the product and very little of anything else for the remainder of the fuel.

Our engines are also now supercharged, so we can bleed a little compressed air off (or just add an air pump or steal some pressurized exhaust gas) and run a second line to our fuel tank(s) and keep the gasoline from boiling. (Pressurized air is also used to keep magnetos from shorting out).

Someone revisits the technology of drop tank and what 5 years before didn't work at all, now works like a charm. And there is stampede to equip planes, especially fighter with this new feature (despite it not being the perfect solution - but very little in engineer doesn't have some trade off).

So, it isn't an expensive bathtub toy versus expensive tanks, it's a viable technology to science fiction one in early/mid 30s when RM should have been building a CV.

Curtiss fighters 1934.
Export Hawk 1937

To fly at 25,000 ft you needed better oxygen systems, enclosed heated cockpits and and few other other things besides pressurized drop tanks.

And if the goal is to either attack enemy ships or keep enemy aircraft from attacking yours ships the need to fly at over 20,000ft is reduced a fair amount.

Curtiss could hang a 52 gallon drop tank under the early 1930s single engine attack aircraft. They could be dropped in flight.

 

[Ascent]

That's exactly my point, no one foresaw that, heck not even the Germans expected France to fall as quickly as it did. Their hubris over it and subsequent invasions of Norway led them to belive their own hype and launch a failed attempt at subduing Britain. Without all this, perhaps British military planners might not have discovered the weakness we can so obviously see with the lens of hindsight.

The invasion of Norway was 9th April, the invasion of France didn't start for another month on 10th May.

 

[Darthtabby]

S Shortround6 I have to admit, the whole "aircraft carrier Italy" concept is so routinely disparged in discourse about naval combat in the Med that I hadn't really thought to question whether it might have been workable with a few changes. However I also agree with some of the other posters that relying on the territory the Axis captured is leaning heavily on hindsight.

I do agree that engines appear to have been one of the major limitations of Italian combat aircraft though it wasn't the only area they were behind. My impression is that the Italians had some outstanding airframe designs, but were behind in terms of engines, armament, radios, etc. (IIRC the SM.79 lacked an intercom for the crew to communicate.) Also that their aircraft industry wasn't really geared towards mass production.

I have admit I have trouble seeing the Breda Ba.64/65 as a carrier type. Given the limitations of the available engines perhaps something more Swordfish like?

nuuumannn Thanks for the info. It at least confirms the idea was studied.

 

[nuuumannn]

The invasion of Norway was 9th April, the invasion of France didn't start for another month on 10th May.

Righto, got the two mixed up.

 

[nuuumannn]

A bit of text regarding the plans to build a carrier-capable Fiat G.55, designated the G.55N,

"The Rome Organisation, as the plan to build an Italian aircraft carrier was codenamed, led to the evaluation and testing of various aircraft types. On 28 October 1942 engineer Giovanni Pegna, who was put in charge of the ship's aeronautical installations on account of his double experience in naval and aviation design, asked Gabrielli (who had worked under him at Piaggio) to build 'a few batches' of G.55s 'suitable for carrier use'. Gabrielli replied that it would be possible to equip them with folding wings and adapt them to carry torpedoes or other launchable weapons. On 2nd November the answer was forwarded to Gen. Alberto Briganti, head of the naval aviation office, adding that a prototype would become available after the 101st production G.55. In January 1943 Pegna informed Gabrielli that after overcoming the initial opposition of Gen. Eraldo Ilari and the Air Armament Staff - the air force had selected the Re.2005 and the G.55 as a second-generation carrier aircraft. Upon receiving the necessary torpedo data, in March Gabrielli set to studying the naval G.55. The project did not go very far and whatever work was carried out was probably used for the subsequent G.55S."

The latter was a (land-based) torpedo-carrying G.55, which did not bear fruit until early 1945, but the single prototype was converted back to standard configuration after the war's end, although handling trials were carried out.

From Fiat G.55 by Piero Vergnano and Gregory Alegi (1998, Ali D'Italia)

 

[Admiral Beez]

The best way for Italy to get carriers is to stay out of the fray, Franco-style. Had Italy remained neutral she could have begun constructing carriers after the battleships Roma and Impero are launched in 1940. By early 1942 it will be clear to all that Germany is screwed in the USSR, especially as the lack of a North African campaign means added supplies going to Archangel and Murmansk. If FDR and Churchill can somehow encourage Mussolini (or his successor after a well-timed regime change) to join the Wallies the Italian carriers would be useful in the Indian Ocean. A declaration of war against Germany isn't necessary, but one against Japan and Vichy France might be useful.

January 1942, Italy comes to terms with FDR and Churchill. February 1942, an Italian force led Admiral Carlo Bergamini and fueled by British oil sails via Suez to the Italian naval base at Massawa with the carriers Aquila and Sparviero the battleships Veneto and Littorio, two CAs, four CLs, six Marconi-class submarines and four bulk oil/supply ships. Two carriers and battleships and some of the other ships sail for Ceylon to meet with Sommerville's Far East Fleet of Illustrious, Formidable, Indomitable and Hermes, keeping in mind that none of these RN carriers have suffered damage in the MTO.

So, how do we see the Italian carriers and their aircrew operating alongside the RN? Nagumo's still coming in late March.

A bit of text regarding the plans to build a carrier-capable Fiat G.55, designated the G.55N,

The Fiat G.55N will be the best allied carrier fighter in the Indian Ocean up to that point. Can it tackle the Zero?

 

[Shortround6]

Time line has some wishful thinking.

First flight of G. 55 was in April of 1942.

More to the point, no alliance with Germany means no (or few) DB 601s let alone DB 605s.
Back to the Italian radials for power plants.

R. 2002 doesn't even show up in time although it might be speeded up?

 

[Darthtabby]

A bit of text regarding the plans to build a carrier-capable Fiat G.55, designated the G.55N,

"The Rome Organisation, as the plan to build an Italian aircraft carrier was codenamed, led to the evaluation and testing of various aircraft types. On 28 October 1942 engineer Giovanni Pegna, who was put in charge of the ship's aeronautical installations on account of his double experience in naval and aviation design, asked Gabrielli (who had worked under him at Piaggio) to build 'a few batches' of G.55s 'suitable for carrier use'. Gabrielli replied that it would be possible to equip them with folding wings and adapt them to carry torpedoes or other launchable weapons. On 2nd November the answer was forwarded to Gen. Alberto Briganti, head of the naval aviation office, adding that a prototype would become available after the 101st production G.55. In January 1943 Pegna informed Gabrielli that after overcoming the initial opposition of Gen. Eraldo Ilari and the Air Armament Staff - the air force had selected the Re.2005 and the G.55 as a second-generation carrier aircraft. Upon receiving the necessary torpedo data, in March Gabrielli set to studying the naval G.55. The project did not go very far and whatever work was carried out was probably used for the subsequent G.55S."

The latter was a (land-based) torpedo-carrying G.55, which did not bear fruit until early 1945, but the single prototype was converted back to standard configuration after the war's end, although handling trials were carried out.

From Fiat G.55 by Piero Vergnano and Gregory Alegi (1998, Ali D'Italia)

Interesting! I find the bit about adapting the G.55 to carry torpedoes particularly interesting. As mentioned previously I've been suspicious of claims that the carrier based Re.2001s would have had torpedo capability as there was only a single land based Re.2001 torpedo fighter, but if the G.55S grew out of a carrier fighter proposal then perhaps the same is true of the torpedo carrying Re.2001.

On a somewhat off topic but still related to Italian aircraft and torpedoes note, can anyone verify that the CANT Z.1007 actually flew combat missions in the torpedo bomber role? It seems to have been capable of carrying at least one torpedo (while many sources state it could carry two torpedoes externally, the Italian language manual in the Technical section lists a single 840kg torpedo as an internal load* and I'm inclined to view an actual Italian language manual as more credible) but sources are mixed as to whether the type was actually used as a torpedo bomber. Is anyone aware of any specific torpedo bombing missions flown by the type?

*There's also an Italian language Aircraft characteristics document over on wwiiaircraftperformance.net that does oddly does not list any regular aerial torpedoes among the armament options, but even more oddly lists underwing carriage of four of the small Motobomba FF circling torpedoes as an option (or one internally).

 

[ThomasP]

As far as I am aware, the Z.1007 was never used for conventional torpedo attacks. Everything I have read says it was used only for level bombing (against ground or ship targets) and reconnaissance.