# Mathis Vega 42

The Mathis Vega 42 was a 42-cylinder 6-bank in-line radial piston engine, designed and built in France, by Société Mathis Aviation in the late 1930s, with development continuing during and after WWII.

## Design and development

Émile E. C. Mathis had begun designing and producing motor-cars from 1910. Société Mathis Aviation, formed in 1937, began designing aircraft engines, initially with the large and complex Vega.
The Vega (and the similar Vesta) had a 2-piece Aluminium-alloy crankcase, 7 Aluminium-alloy cylinder blocks, with one-piece Aluminium-alloy heads and steel cylinder liners. A 6-throw crankshaft ran in 7 plain bearings.
Development continued after the war, culminating in the 119.4 L (7,290 cu in) 3,700 kW (5,000 hp) Vesta 42, which did not reach the hardware stage before Mathis closed its doors.

## Operational history

The Vega engines were run on test-beds, and some sources indicate the engine was flown 100 hours in a test bed aircraft during 1939, but no details of flight testing survive.

## Variants
### Vega 42A

    Initial version of the engine first run in 1938, rated 1,700 kW (2,300 hp) at 3,000 rpm. Two examples and a full-scale mock-up are reported to have been built.

### Vega 42B

    An improved variant, under development in 1940. Completed and unfinished engines were hidden from invading German forces, in the Pyrenees.

### Vega 42D

    An enlarged capacity version which became the Vesta 42.

### Vega 42E

    Post WWII development rated at 2,100 kW (2,800 hp) for take-off.

### Vesta 42

    An enlarged Vega, developed from 1942, with similar configuration, but 158 mm (6.22 in) bore, 145 mm (5.71 in) stroke and 119.4 L (7,290 cu in) displacement, rated at 3,700 kW (5,000 hp).

## Specifications (42E-00)

Data from Old Machine Press: Mathis Vega 42-Cylinder Aircraft Engine, Aircraft engines of the World 1946

### General characteristics

* Type: 42 cylinder in-line radial engine (6 7-cylinder banks)
* Bore: 125 mm (4.92 in)
* Stroke: 115 mm (4.53 in)
* Displacement: 59.3 L (3,620 cu in)
* Length: 1,520 mm (59.84 in)
* Diameter: 1,070 mm (42.13 in)
* Dry weight: 1,180 kg (2,600 lb)
** Maximum Brake Mean Effective Power (b.m.e.p.) 13.4 kg/cm$^2$ (191 psi)

### Components

* Valvetrain: 1 exhaust and 1 inlet valve per cylinder driven by 7x single overhead camshafts (SOHC)
* Supercharger: Gear-driven single-stage driven at 5.53:1, with automatic boost control.
* Fuel system: 1x Zenith 160 2-barrel downdraught carburetor
* Fuel type: 100/130 Octane aviation gasolene
* Oil system: Pressure feed at 690 kPa (100 psi), dry sump using 25.1 cs (0.00418 min) viscosity oil
* Cooling system: liquid-cooled
* Reduction gear: Epicyclic bevel reduction gear at 0.42:1

### Performance

* Power output: Take-off:2,100 kW (2,800 hp) at 3,200 rpm at 1.2 m (3 ft 11 in) +8.6lb boost
                Normal:1,700 kW (2,300 hp) at 3,000 rpm at 2,000 m (6,600 ft)
                Cruising:1,300 kW (1,700 hp) at 2,500 rpm at 2,000 m (6,600 ft)
* Specific power: 35 kW/L (0.77 hp/cu in)
* Compression ratio: 6.5
* Specific fuel consumption: 0.292 kg/kW (0.48 lb/hp) per hour, cruising
* Oil consumption: 0.011 kg/kW (0.018 lb/hp) per hour, cruising
* Power-to-weight ratio: 0.57 kg/kW (0.93 lb/hp)