SNCASE SE.580, the most powerful french WW2 aircraft

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caid’s suggestion #116

I would like to suggest most powerful French WW2 aircraft, the SNCASE SE.580

A few months before the Battle of France, French engineers proposed a fighter that was built around two vertically arranged engines. Despite the great technological complexity, the project was approved and handed over to the SNCA concern (Societe Nationale de Constructions Aeronautiques). Before the defeat of France, the advanced calculations and sketches did not advance the work, but the idea was developed two years later.
At the end of 1942, the design was continued by specialists from Dewoitine, which operated under the supervision of the German administration in Toulouse. The plane was now positioned as a fighter bomber and carried the designation S.E.580. Despite the full occupation of the country in November, the Germans ordered to continue work on this machine and in 1943 the airplane model was provided for purging in a wind tunnel SNCASE. By this point, the fighter has found its final appearance.

The construction of the S.E.580 was based on the produced fighter D.520, from which the wing, vertical tail, and individual elements of the fuselage were borrowed. The main “highlight” of the aircraft was the 24-cylinder engine Hispana-Suiza 24Z, which consisted of two 12-cylinder engines. The expected power of the pair was supposed to be 2500 hp, but in several other sources, the power was rather 3000 or 3600 hp. Each of the “halves” of the X-shaped engine had a separate shaft and rotated its coaxial screw (three-bladed, metallic, variable pitch). Since it was required to ensure good cooling of the power plant with the minimum allowable drag, the engine hood was extremely “crimped,” while the radiators were placed horizontally in the tunnel behind the pilot’s cabin, and the air intake was moved upward. This gave S.E.580 a characteristic and easily recognizable “hunchbacked” appearance. At the same time, according to mass-dimensional characteristics, this aircraft came very close to two-engine bombers.

The Germans’ interest in this project was very high - in the beginning of 1944, even the construction of a prototype was initiated, but the Allied landing in Normandy undermined these plans. After the change of administration to S.E.580 returned again and at the end of the year an order was issued for the construction of two prototypes. It was assumed that the aircraft would be equipped with one 30mm in the propeller four 20mm cannon Hispano-Suiza and eight 7.5mm machine guns in the wing, which together with high-speed data would make S.E.580 a very dangerous enemy. In addition, it was planned to suspend bombs weighing up to 500 kg. in 1946, the height 7.5mm in the wing was changed for six 12.7mm (3 per wing)

While prototypes were being built, the “mechanics” tried to bring the X-shaped engine to the conditioning state. Although the idea of using Hispana-Suiza 24Z was not a failure, it took a lot of time to refine it. In order not to impede the process in 1946, it was decided to install on a prototype a more powerful German engine Jumo 213 produced by arsenal in France (4000hp Arsenal 24H), with one five-bladed propeller. Estimating the amount of improvements French experts concluded that this proposal is not rational and work on S.E.580 was suspended. The last argument in favor of refusing such “artifacts” was the appearance of mass production over a jet aircraft. So without waiting for the X-shaped engines, both prototypes were dismantled. The only thing that was used from the S.E.580 project is the air intake layout, which was used on the experienced SS-2410 and S.E.2415 “Grognard” attack aircraft.

Firepower
the aircraft was capable of fighting and close air support. the armament is rather heavy and will easily deal with any enemy planes as long it can touch it. the aircraft was also having the capacity to carry bombs.

the planned armament in 1943 included 1x 30mm, 4x 20mm, 8x 7.5mm

  • 1x 30mm HS 825 auto-cannon, in the hub, 20 rounds carried
  • 4x 20mm HS 404 auto-cannon, in the wings, 150 rounds per guns
  • 8x 7.5mm MAC 39 machine-gun, in the wings, 500 rounds per guns

in 1946 the armament was revised to meet the standard of the time

  • 1x 30mm HS 825 auto-cannon, in the hub, 20 rounds carried
  • 4x 20mm HS 404 auto-cannon, in the wings, 150 rounds per guns
  • 6x 12.7mm M2 machine-gun, in the wings, 400 rounds per guns

whatever the armament Gaijin decides the give it, it would still be interesting to have.

the plane also had 2 hardpoints under the wings which were capable of carrying 500kg bomb each.

Flight performance
the aircraft never took off, so the flight performance is theoretical. the aircraft was mounting the X-shaped Hispana-Suiza 24Z providing 2500-3600 hp depending on the altitude in 1943. but a second engine was proposed in 1946. X-shaped Arsenal 24H with the power of 2800hp to 4000hp according to the altitude. the highest performance was during the take-off course. the plane weighs 8,128 kg in full load.
the speed of the plane is also interesting. it will be different depending on the altitude

  • 600 km/h at sea level
  • 749 km/h at 9000m

the climbing rate was also interesting

  • 0-6000m = 16.66 m/sec

this plane performed pretty well amounts the late WW2 aircraft. the weight being mostly in the nose will give the plane a maneuverability similar to the conventional planes. the design makes me believe the turn rate will not be that bad but maybe not as good as the Bf 109 or Spitfire. maybe closer to the P-63 which is not bad at all.

to help the performance, the plane includes a serial device that can affect the handling in the air

  • combat flap
  • landing flap
  • take-off flap
  • airbrake

Survivability
this fighter is capable of taking a beating. while not a flying tank like the IL-2 it is much more protected than the usual fighter. thanks to the many plates of armour whose thickness is not stated but we can guess it.

  • 38mm bulletproof glass in front of the pilot
  • 8mm steel plate behind the pilot
  • 8mm steel plate behind the engine & in front the pilot
  • 5mm steel plate behind the radiator tunnel

the plane is made of all metal construction which makes it rather well resistant to damage. the part will also have a good resistance to overspeed breaking point. this is seldom shown in the details of the planes but we can assume the breaking point will be similar to the VB-10 which is a plane of the same kind.

  • Landing gear = 450 km/h
  • Wings = 820 km/h
  • combat flap = 498 km/h
  • take off flap = 469 km/h
  • landing flap = 320 km/h

Sources

Engine

Hispano-Suiza 24Z engine

Arsenal 24H

Armament

8 Likes
2

It’s a wild design and I’m not totally against adding planes that never flew. It would add a real super prop flavor to the French tree.

1 Like
3

+1 looks mental

4

This is one hell of a fighter, and perhaps both armament versions could be added? +1

1 Like
5

It look marvelous, and having a French design at Rank 4 would be great, since the VB.10 is now down to rank 3.

1 Like
6

Yes.

I love everything about it, and that armament sounds monsterously good.

+1

7

I really doubt those higher power numbers, the Hispano Suiza engine was a pretty outdated design and struggled to reach 1500hp on the VB.10s.

So the 3600hp might just have been a “what if”, because AFAIK they never got individual 12cyl engines to 1800hp. 2500 and even 3000hp are likely, though.

8

Hispano Suiza was building very good engine and the VB-10 was a plane built in a hurry to restart the french air industry. it was full of flaws due to the rush of development and production. the engine was from 1939 and untested for services.
but this do not mean Hispano Suiza was without development for their engine. they had a bunch of other engine in production for other planes.
the Arsenal 24H was tendem Jumo 213. the power was verified

the HS 24Z was indeed having a high power but also had a lot of issues, some important enough to had destroy the engine during test. it was the reason why the Arsnald engine replaced the Hispano-Suiza

9

I was talking about the 24Z and the 12cyl engines that lead to it specifically. The 24H and the Jumo 213 are just different beasts altogether, was it ever mounted in the SE.580?

10

apparently yes, but the plane was never finished. the picture shows the 24Z. i have no picture of the 24H

2 Likes
11

This vehicle is absolute must. I dont really understand why it is not in the game already.

12

Probably because, for the most part, it’s an unrealistic pipe dream. Such an overly ambitious project may well have turned out to be a total flop.

13

Like Maus or M6A2E1 for example? Such vehicles wouldnt be good vehicles in real combat yet in game they work very well.

14

The Maus yes. Although even that was actually built and tested (I think) it just turned out to be a proven flop.
The SE.580 may have had huge problems in the design that made them abandon it after they started test flight attempts, or may have fallen well short of the projected performance. For such lofty expectations, either is likely.
But again, I’m all for it being added as it was expected to be, with that armament and speed it’d be a fun plane for sure.

15

Sidam 25 mistral, E-100, R3 T-106 FA, R2Y2, Ho-Ri (even the prototype was never build)

there is a bunch of vehicles in-game who was barely built and others that are simple paper concepts.
compared to the the SE.580 was quit advanced in his development

16

Correct. Some concepts are more believable than others, like the R3 T-106 is more likely to have worked than an E-100. The R3 takes a proven vehicle and mounts a proven gun on top. Nothing too out of the ordinary.
Out of curiosity, were either of the SE.580’s projected engines ever used on a functional aircraft?

17

It was passed to the developers for consideration back in 2021:

18

Devs have already said many times that the R2Y2 and Ho-Ri are not to be used as examples since they’re very old.

19

rgw R3 T106 never worked, it was just listed in the brochure as a potential turret they could eventually put on the vehicles if asked. there were a dozen of those turrets proposed, and this is the same for almost every tank’s development, they always have a bunch of turrets, engines and armament proposed during the development.

the Sidam 25 Mistral was photoshopped to have the mistral as Italy was negotiating with France to get the missiles which never ended up being possible

the Ho-Ri was only on paper. there was a production plan for 5 vehicles in 1945 which skipped the prototype stage but Japan never could do it as they surrendered a few weeks later. Gaijin even added 2 versions of this tank knowing it was never built at all.

The E-100 was far from being ready but at least a lot of his part was built and in the game, this tank is a very rare vehicle and hard to get.

the R2Y2 is completely an early paper design. japan never built any and was known to be unable to build a single one with its industrial capacity.

20

they were aware the vehicle was never built before adding it, and in the case of the Ho-Ri, they were already knowing it was never built and already had started their current policy. it might be old, but keep in mind the policy is also old and they already had removed the Tiger II (10.5 com) Panther II & coliant from the game when they added it. and they added both model 3 months apart about a year after Japan got their ground forces.

basically, that is a case of the Snail doing what the Snail wants
here is some lettuce to offer as tribute to lord snail