Various Aircraft Specifications for a Video Game Mod (1 Viewer)

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Darthtabby

Airman
59
16
May 22, 2021
Hello All,

I'd recently started helping to do some aircraft research for a Hearts of Iron IV (video game) mod called Ultra. Ultra's raison d'etre is providing a more historically accurate industry model, but it also aims to replace the base game's generic air units with nationally unique, more historically accurate ones. Since I'm likely to have to seek information on a lot of different aircraft over the course of my research I thought it would be best to make a single general thread rather then one for each specific type of plane.

In a lot of cases I will probably be asking for specific pieces of information that I find difficult to find though here's an overview of the specifications I have been asked to find in general (they will be entered into a formula that has been developed to determine the aircraft's in game stats).

- air to air weapons
- different possible bomb loadouts (if possible) with a preference for multiple smaller bombs over larger bombs
- max power to weight ratio at standard take off weight
- range of the aircraft*
- empty weight, number of engines
- is it designed as a ground attacker or armored (or both)
- wingspan + (is it a float- of biplane)
- maximum speed
- service ceiling

*I'm aware that range varies significantly with payload. Thus far I've been passing along load info when it is specified in conjunction with range.

Anyway the first aircraft I am interested in getting information on is the SM.79 Sparviero. I have a pretty complete set of specifications for early production 126 powered SM.79s thanks to the manual sandokan sandokan uploaded over in the technical section (though I do wonder if the range figures in that manual may be somewhat optimistic). But I'm less certain about later versions of the aircraft. I was reading that the Piaggo powered SM.79-II was more or less a propaganda myth and that only a single prototype with that engine fit existed. I was also sent some info indicating that SM.79s were modified with ethyl injection and eventually 128 series engines optimized for low altitude, but there doesn't seem to be a model designation associated with this aside from the bis upgrade which appears to largely be an amalgamation of various modifications that had already been used on existing torpedo bomber SM.79s. Going by what Wurger Wurger told me Series I, II, and III actually refers to production batches rather then specific engine fits.

Gathering the info I've received so far together, it sounds like the SM.79 did receive various upgrades including significant upgrades to the engines and fuel capacity, but there doesn't seem to have been much in the way of particular model designations associated with those upgrades until they were brought together as a factory conversion in the bis model. Does that seem more or less correct?

(Okay, I guess in the case of the SM.79 I'm starting off by trying to determine what the major Regia Aeronautica models actually were before I get too much into the specific specifications of the upgraded versions.)
 
... I was reading that the Piaggo powered SM.79-II was more or less a propaganda myth and that only a single prototype with that engine fit existed.

According to my info the SM.79 II was powered by the Piaggio P.XI R.C.40 and as had mentioned earlier , the second series was being assembled from 1940 to 1943. The series included the bomber and torpedo-bomber planes.
Your info quoted above seems to refer to the series I. The military prototype of the SM.79-I was powered by the Piaggio P IX Stella R.C.2 while the rest of planes for the Reggia Aeronautica was powered by Alfa Romeo 126 R.C.34 engines. The first series also included 45 planes for Yougoslavia with Alfa Romeo 128 R.C.18 engines.
 
According to my info the SM.79 II was powered by the Piaggio P.XI R.C.40 and as had mentioned earlier , the second series was being assembled from 1940 to 1943. The series included the bomber and torpedo-bomber planes.
Your info quoted above seems to refer to the series I. The military prototype of the SM.79-I was powered by the Piaggio P IX Stella R.C.2 while the rest of planes for the Reggia Aeronautica was powered by Alfa Romeo 126 R.C.34 engines. The first series also included 45 planes for Yougoslavia with Alfa Romeo 128 R.C.18 engines.

Do you mind if I ask the source for your info? The claim that the Piaggo powered S.79-II was a propaganda myth that only existed in prototype form came from some info I was PMed between making my introductory thread and making this one. Source for the claim is Savoia Marchetti S.79 in Action by Robert Gentilli. Googling the publication data it appears to have been published in 1986 though so its certainly possible newer archival evidence has come to light since then.
 
The source is the "Typy Broni i Uzbrojenia" (TBiU) no.199 by Wieslaw Bączkowski, Bellona publication Warsaw 2002.
Also there is an info that the assembling of the SM.79-II started in October 1939. Most of them was adjusted to be the torpedo kites. The engines were the Piaggio P XI R.C.40 but also there were used the Fiat A.80 engines.
Certainly, the author may be wrong. Perhaps our Italian members could help if they can come..
 
SM.84 had the Piaggio engines. I have seen claims that the SM.79 II had Alfa 126 or 128 engines tuned for low-alt performance.
The S.79bis AKA SM.79 III still had Alfa 126 RC34 engines according to a 1943 manual
the book Ali d'italia number 11 with the second part of their S.79 coverage may be of help if someone has access to it
 
Ah right the other manual Sandokan posted was for a torpedo bomber model designated -bis. The cover specifies Per Motori Alfa 126 R.C. 34 so it doesn't entirely rule out that there could have been -bis versions with other power plants as well. I wasn't able to find any mention of the ethyl injection upgrade for the 126 mentioned elsewhere though the later aircraft does seem to have a few differences from the older 1938 manual such as an extra machine gun and protection for the auxiliary tanks. Oddly despite the manual having Aerosilurante in the title the aircraft overview at the start of the manual makes no mention whatsoever of a torpedo bombing role, not even in the section covering armament. Instead the aircraft is referred to as something to the effect of "fast daylight bomber and long range reconnaissance aeroplane."

(On a related note, does anyone know what S.E.M.A.P.E./semape is? Both Sm.79 manuals make reference to the main tanks being coated with it -the context makes me wonder if its some sort of material to make them self sealing.)
 
The SEMAPE was a specialized manufacturer that developed materials for self-sealing fuel tanks. In the case it was a rubber sponge pressed/ wrapped with a fabric tape.
 
Thanks Wurger Wurger !

While I welcome further information on the SM.79, I'd also like to get started on a second question: when did the Hellcat and Corsair start being outfitted to carry heavy weapons for ground and surface attack? I was reading an online resource on USAAF fighters that noted that many of them received the capability to carry bombs and rockets midway through production -in some cases within a single letter code (for instance depending on the sub model a P-47D might be delivered with no ability to carry bombs, the ability to carry bombs under the fusealge, or the ability to carry bombs under the fuselage and wings). Did something similar occur with the Navy fighters?
 
I welcome further information on the SM.79

Here's a little more on the fictitious 'III' designation. From Air International August 1984...

Scan0519.jpg
 
Here's a little more on the fictitious 'III' designation. From Air International August 1984...

View attachment 624612

That's in line with the info another member PMed me earlier, but the SM-79bis manual Sandokan posted in the Technical subforum seems to contradict it: that manual suggests the -bis had the exact same engines as earlier SM.79s and maintained the ability to carry bombs. Though at noted earlier that manual is a bit strange with having Aerosilurante (torpedo bomber) on the cover but no mention whatsoever of a torpedo bombing role in the aircraft overview or armament sections (which are rather short as it was primarily a parts manual).

Maybe I should take a look at the forum fubar mentioned.
 
it seems the sm.79bis was further modified after the armistice to be used as pure torpedo bomber.
So internal bomb bay sealed and used for fuel tanks + engine changed to Alfa 128 with more power down low
 
it seems the sm.79bis was further modified after the armistice to be used as pure torpedo bomber.
So internal bomb bay sealed and used for fuel tanks + engine changed to Alfa 128 with more power down low

These aircraft were definitely still referred to as -bis models? They didn't get their own designation?

Are you aware of any model designations for upgraded S.79s in RM service aside from the -bis designation?
 
The term "bis" is French and roughly translates to "second", so in the aircraft world, "bis" means "second or improved".

So if you have a particular aircraft type that has had an improvement or modification but not enough to warrant a new designation, it would simply be improved or "bis".
 
Bis is Latin, as in bis, ter, quater...

All S.79's in Italian service mounted Alfa 126 engines, apart from the Bis series with Alfa 128.

I do not recall any use of water injection for the engines in any of the versions.
 
Bis is Latin, as in bis, ter, quater...
The Romans weren't part of the foundation of flight, however, the French were.
This is why "bis" was commonly used in early aircraft manufacturing terms, such as the Nieuport 17bis, Nieuport 24bis.
During the days of the Imperial Russian court, French was a common language in certain circles, including their aircraft pioneers - which is why the term "bis" was (and is) used in their aircraft terminology.
 
I was wondering why the bis designation showed up in both Italian and Soviet aircraft designations...

Speaking of which, what sources would people recommend for Soviet WWII aircraft? Not only for specifications, but just getting an overview of what models/variants existed and when they entered service.
 

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