Arsenal VB-10

The Arsenal VB-10 was a French Tandem engines  fighter prototypes developed during and shortly after World War II. It was a monoplane with largely orthodox configuration and retractable tailwheel  the VB 10 added a second engine behind the cockpit which drove a second propeller, coaxial with and counter-rotating to the propeller driven by the engine in the nose. Although the aircraft was first designed (and indeed ordered) in 1940, but because of French occupation, the aircrafts could not flown until  Europe was freed .But then, the Amee de air changed their favor on the jet technology and age of piston engine was over so the project was cancelled  in 1948 and all 6 prototypes were scrapped.
Specification
General characteristics

• Crew: one, pilot
• Length: 12.98 m (42 ft 7 in)
• Wingspan: 15.49 m (50 ft 10 in)
• Height: 5.2 m (17 ft 1 in)
• Wing area: 35.5 m² (382 ft²)
• Powerplant: 2 × Hispano-Suiza 12Zars-15/16, 860 kW (1,150 hp) each

Performance

• Maximum speed: 700 km/h (435 mph)
• Range: 7,700 km (1,056 miles)
• Service ceiling: 11,010 m (36,120 ft)
• Rate of climb: 10.2 m/s (2,008 ft/min)

Armament

• 4 × 20 mm Hispano Suiza  HS-404 cannons 

References 

• http://en.wikipedia.org/wiki/Arsenal_VB_10
• http://www.aviastar.org/air/france/arsenal_vb-10.php

Dewoitine /Sud Est SE 580

In 1944, when France been freed , the Aeronautic Manufacturing National Societies or SNCA try to built a new type of fighter based on the project of the SNCA du Midi M 580-an early design of SE 580 in 1940, the SE 580 wing planform-with its near mid-chord single spar and its empennage surfaces planforms-was similar to the D520, albeit the horizontal planes had slightly greater aspect ratio. Initially designed to be powered by the 24-cylinder Hispano Suiza 24Z (H type) of 2,000hp, its postwar redesign accommodated the 24-cylinder arsenal 24 H of 3,400hp. This latter engine used the cylinder blocks of the German Junkers IV12 213 engine.

Two 12.1-foot-diameter coaxial, counter-rotating propellers were to be utilized for propulsion.

It was to be armed with a 30mm cannon firing through the propeller axis, plus four 20mm cannon and either eight 7.Smm or six 12.7mm machine guns mounted in the wings outboard of the propeller arc. A 500kg (1,100 lb.) bomb could be carried beneath the fuselage. It is obvious that the after-cockpit buried radiator with top-mounted radiator intake was for protection from ground fire.

One thing was sure is 2 prototypes were ordered but they were not complete because the project was cancelled when the Amee de Air( French airforce) focus more on jet fighters along with it competitor-the Arsenal VB-10 shortly thereafter.

Specification

• Powerplants:Hispano Suiza 24Z(2x Hispano Suiza 12Z)
• Armaments:30mm cannon in the props axis, 2x HS 404 cannons in each wing
• Propellers:6 blades contra rotating props or 5 blades counter rotating prop
• Span 15.862m
• Length 13.000m
• Weight 5093kg 
• Maximum speed 749km/h

 References: http://www.aviationbanter.com/showthread.php?t=76826http://findarticles.com/p/articles/mi_qa3897/is_200102/ai_n8931139/