Fiat G.55 with Isotta Fraschini Delta

[carlo961]

In an old issue of "Aerei" dated circa 1976, in an article written by C. D'Agostino and dealing with Fiat G.59, I read a quite strange (at least for me) statement.

According to Mr. D'Agostino, in the process that brought Fiat to evolve the G.55 (with Daimler-Benz under licence) to the G.59 (with Packard RR Merlin), Fiat technicians tried to install at first an Isotta Fraschini Delta in a G.55 (or in the sole G.56 prototype) airframe.
But the performances with IF Delta were quite disappointing, so the G.55 was then modified and tested with an RR Merlin taken from a Supermarine Spitfire IX, loaned by Aeronautica Militare Italiana to Fiat for this purpose.
The rest is well known.

In my opinion is quite dubious that Fiat ever installed an IF Delta engine in a "Centauro". At least I never saw a photograph of a G.55 modified in such way.

Are my assumptions uncorrect ? Please let me know.

 

[archipeppe]

In my opinion is quite dubious that Fiat ever installed an IF Delta engine in a "Centauro". At least I never saw a photograph of a G.55 modified in such way.

This is new to me.
I've never heard about coupling experiment among the G-55 and the Delta.
I doubt that Gabrielli really would do it.

The modification that lead to G-55 to G-59 started somehow casually, but rapidly evolved in a precise direction. The final result was that the G-59 looks more the P-51D rather any other Italian fighter, and had enhanced performance and ammo.

 

[Skybolt]

Surely a lot of Deltas III Series were in storage after the war, but modifying an already built fuselage of a G-55 for it wouldn't have been a trivial task. For example, a large air intake would have to be built in the nose under the spinner to allow for air colling (besides the fact that the effect of substituiting a 1250 HP engine with a 700 one would have been predictable even before actually doing it). And the engine attachment was completely different. As an aside, I can add that in 1948 SIAI Marchetti briefly studied a Delta III-powered SM-92, intended for ground attack (and still anther version with an entirely different engine). It would have been a new construction, since the the wreck of the only SM-92 built had been disposed-of in 1946. More in ISP.

 

[carlo961]

Skybolt, I agree with you that a G-55 "Delta" should be seriously underpowered, but in my humble opinion the conversion was not technically impossibile: remember the similar case of the Re.2001 “Delta”.
Neverthless, also the installation of the RR Merlin in the G.55 required a not negligible re-design of the fuselage front, because the RR Merlin was an upright V12 engine, while the Daimler-Benz was an inverted V12, like the IF Delta.
This latter engine was smaller and moreover lighter than the DB.605 (about 500 Kg against 700 Kg declared for the DB.605). Very likely, the different engine weight should have caused some troubles for the correct balancing of the aircraft, only slightly compensated by the deletion of the cooling system (coolant radiator, cooling piping and so on).

 

[Bailey]

From "Fiat G 55, Piero Vergnano & Gregory Alegi, Ali D'Italia 10"

Regards Bailey.

 

[archipeppe]

From "Fiat G 55, Piero Vergnano & Gregory Alegi, Ali D'Italia 10"

Regards Bailey.

Mmmm..... interesting the source should be attendible.

 

[Skybolt]

Absolutely, the fact is recorded also in the autobiography of Gabrielli (the projects list is at the end). What I said is that it was a technical dead-end and more easily said than done, expecially if done starting from an already built airframe.

 

[archipeppe]

Absolutely, the fact is recorded also in the autobiography of Gabrielli (the projects list is at the end). What I said is that it was a technical dead-end and more easily said than done, expecially if done starting from an already built airframe.

But, at the end, what advantage could be matching the G-55 airframe with a less powerful engine (as the Delta was)?
Usually designers always try to exploit powerful engines rather in order to have better performace....

But a Delta-powered G-55 would be less useful of a standard G-55 (and even less attractive), at least could be really used only as advanced trainer.

 

[Bailey]

But, at the end, what advantage could be matching the G-55 airframe with a less powerful engine (as the Delta was)?

My best guess is that lower cost and local supply were the keys issues. There would have been no guarantees of getting foreign engines. The potential customer base available to the Italians would also have probably been driven by cost rather than performance issues.

Regards Bailey.

 

[Skybolt]

Yep, DB-605s were in low supply, Merlins were needed for the Spitfires and Lightning used by the Italian Air Force (the Spits were expecially in a real bad shape, since they were already worn-out during wartime) and there were a lot (relatively, maybe less than a couple of hundreds) of Deltas around. And, yes, the converted G-55 were intended for training, advanced training, "allenamento caccia" as was said back then. The Argentines were interested, and keep in mind that not being part of ONU Italy could ignore the embargo on Middle Eastern powers, and put it to profit selling to either side (officially to Egypt and Syria, unofficially aiding Israel in a lot of ways, for example, the training school for Israeli combat pilots was... just outside Rome). See the last issue of Storia Militare for some amusing episodes.

 

[archipeppe]

See the last issue of Storia Militare for some amusing episodes.

Ah.... Storia Militare, Aerei nella Storia and others, here I can only read La Fana de l'Aviation (nice but not in Italian).

 

[archipeppe]

I realized this rough photocomposition only to get an idea of the beast's appearence (Gabrielli forgive me....).

 

[carlo961]

When I have time ??? I will post the article written by Mr. D'Agostino, since I retrieved it.

In the article Mr. D'Agostino wrote that he had the informations about the G.48 (G.55 with IF Delta) from Mr. Nino Arena. In other words, Nino Arena stated that the G.48 flew.

It could be interesting to retrieve a photograph of such aircraft, whenever it really existed.

Indeed I started this topic just because only in the article of "Aerei" there was a such startling statement.

Frankly speaking, in my opinion it is too much simple to close the question saying that the G.48 never flew because someone made this statement, without supporting documents.

Thank you Archipeppe for your G.48 "artistic rendering".

A little OT: the G.59 was equipped with a Packard built Merlin, since it was cheaper than the original RR built Merlin. All production G.59 were equipped with brand-new Packard built engines.

 

[archipeppe]

Thank you Archipeppe for your G.48 "artistic rendering".

You're welcomed Carlo, anyway when I have time (or hope so) I will try to make a brand new drawing of mine instead of a photo collage.....

 

[Skybolt]

Mustangs, not P-38. Sorry, too much wine on Eastertime...

 

[Skybolt]

Nino Arene wrote that ? Ohmygod....

 

[carlo961]

Yes, I confirm. Nino Arena wrote that.
Yesterday I browsed also the (not bad) book of Mr. Nicola Malizia entitled "Fiat G.59, storia di un addestratore", first edition 1982, where is described also the transition from G.55 to G.59, but no mention to an alleged G.48 neither built nor flown is reported.

 

[Skybolt]

Carlo, my remark was ironic... Nino Arena is not known for accurateness...

 

[Silencer1]

Hi!

Sorry for interrution, although I hope, that partcipants of this topic knew history of Italian aircraft engines much better then I.
So thequestion is - why after world-know Schneider Tropy racers (which have been equipped with supeb Fiat engine) Italian civil and military aircraft in 1930-40th in total use the rmedium-class air-cooled "stars" or minor-class air-cooled in-line engines? The most powerful engines became German DB and most modern types has been equipped with it?

So, why here were no powerful Italian (water-cooolde) engines in series production during World War 2

Thanks in advance!

 

[Skybolt]

The long answer will require a couple of books, the short one just eight words: end of investments on part of the government.

 

[Silencer1]

Hi Skybolt!

The long answer will require a couple of books, the short one just eight words: end of investments on part of the government.

Well, the short answer is more then enough for me

But why government stops investment in such important area?
In USA, Germany, UK the powerful engines allows the aircraft builders to made highly advanced and capable aircraft available to air force. Why in Italy it was decided to stop the development?

Cheers

 

[Justo Miranda]

Piove!...porco governo

 

[red admiral]

You might be a little harsh on the Fiat A.38, it's development was a lot later than the DB601 or Merlin, starting in the late 30s when it seemed like it might be a good idea after all to have a powerful inline engine. The engine was barely built by the time the DB601 and 605 were available from Germany midwar. I don't think the many changes in layout helped the A.38 either. The contemporary racing engine the A.38 was based on, the AS.8 seemed pretty reliable at around 2000hp with power up to around 2500hp achieved in testing. - Aereonautica Italiana museo storico catalogo motori

 

[Artie Bob]

The late model Allisons, as in the P-82, IMHO seemed to be right up there with the late model Merlins, etc. I am predjudiced because I grew up near a base operating P-82s and my daily thrill was watching them make high speed passes at about 500-1000 feet altitude. The late versions had higher boost and in my memory had a quite different sound from P-40s that flew over. The perceived problems with the Allisons had much to do with development priorities and administrative decisions, not so much the basic design. IIRC some Allison components are used in current racing Merlins.

Best regards,

Artie Bob

 

[Skybolt]

The A.38 saga is a still unknown one. Relevant docs are almost all gone (expecially the internal FIAT ones, locked away in remote storage with no access for researchers). Main problems seems two: too little time to develop and lack of suitable alloys. The Regia itself wasn't so skeptics on the A.38 itself as much as its timing. The H-architecture A.44 was based on the cylinder banks of the A.38, and it was funded by the Regia in a lavish manner. Moreover, same problem was suffered by other contemporary Italian in-lines (the IF ones). All-in-all, lack of alloys (and skill in machining them) meant that HP-for-HP Italian in-lines were heavier. The RA-1050, meant to be a copy of the DB-605, was 12-15 per cent heavier due the alloy substitution, and FIAT had German technicians assistance and actual original engines to copy.
The AS.8 comparison isn't actually fit. First, it never flew, second, it was using very-high grade gasoline that was impossible for an operational military engine. Don't forget the immediate predecessor of the AS.8, the AS.6, was a dead end (two engine bolted together) devised for the Schneider (and there are doubts that the MC-72, when flown in a Schneider-type course, would have ever succeded, just look at the very laaaaaaaaaaaaarge turns Agello used in the record run and compare with the tight Schneider turn, and imagine the torsion forces of the very long and fragile engine and shaft). The AS.8 was a new start, FIAT could not build on previous recent developments.

 

[hesham]

Hi,


the early version to Fiat G.55.