# Turbomeca Turmo

The Turbomeca Turmo is a family of French turboshaft engines manufactured for helicopter use. Developed from the earlier Turbomeca Artouste, later versions delivered up to 1,300 kW (1,700 shp). A turboprop version was developed for use with the Bréguet 941 transport aircraft.
Current versions are built in partnership with Rolls-Royce, and the engine is produced under licence by the Chinese Changzhou Lan Xiang Machinery Works as the WZ-6 and Romanian Turbomecanica, Bucharest, as the Turmo IV-CA.

## Design and development

The Turmo was initially developed with a single-stage centrifugal compressor, annular combustion chamber and single stage turbine. Power output was from a single-stage free power turbine and was initially 200 kW (270 hp).
During early post-war helicopter development, the use of cold and hot rotor tip-jets was widely investigated. To provide large mass-flow air for efficient operation of the tip-jets, Turbomeca developed a gas turbine driven gas producer, powered by the free power-turbine of the Turmo to deliver the required gas flow.

## Variants

Data from:-Jane's all the World's Aircraft 1957–58

### Turmo I

    The initial version of the Turmo; max continuous gearbox output 200 kW (270 shp) at 3,000 rpm, at 33,750 rpm gas generator speed.

### Turmo II

    Developed version of the Turmo I; max continuous gearbox output 240 kW (320 shp) at 34,000 rpm gas generator speed.

### Turmo III

    With 2-stage free power-turbine, pressure ratio 5.7:1 ;Maximum shaft output 560 kW (750 shp), max continuous 450 kW (600 shp) at 33,400 rpm

### Turmo IIIC

    A 890 kW (1,200 hp) turboshaft powering the Sud-Aviation Frelon prototypes.

### Turmo IIIC$_2$

    Developed from the IIIC delivering 970 kW (1,300 hp) maximum output

### Turmo IIIC$_3$

    Maximum rating 1,100 kW (1,500 hp) at 33,500 rpm for production Super Frelon helicopters

### Turmo IIIC$_4$

    Military variant.

### Turmo IIID

    Turboprop for the proposed Breguet Br 942 STOL transport, maximum rating 913 kW (1,225 hp).

### Turmo IIID$_2$

    996 kW (1,335 hp) at 22,460 free turbine rpm

### Turmo IIID$_3$

    1,080 kW (1,450 hp) at 33,500 rpm

### Turmo IVB

    Military Variant

### Turmo IVC

    Civil Variant

### Turmo IV-CA

    Licence production in Romania

### Turmo VI

    Turboprop engine with two axial stages, one centrifugal compressor stage and two free power turbine stages, rated at 1,300 kW (1,800 hp) at 32,000 rpm.

### WZ-6

    Licence production at the Changzhou Lan Xiang Machinery Works in the People's Republic of China.

## Applications
### Turboshaft

* Sud-Est SE.3140 Alouette II
* Aérospatiale SA 321 Super Frelon
* Aérospatiale SA 330 Puma
* Bölkow Bo 46
* IAR 330
* SNCASE SE.3200 Frelon
* Turbotrain
* SNCF Class T 2000
* N.300 Naviplane

### Turboprop

* Breguet Br 940 Integral
* Bréguet 941
* Breguet 941S

### Automobile

* Renault Étoile Filante

## Specifications (Turmo IIIC$_7$)

Data from Flight International.

#### General characteristics

* Type: Two-shaft turboshaft
* Length: 182 cm (71.65 in)
* Diameter: 71.6 cm (28.19 in)
* Dry weight: 325 kg (717 lb)

#### Components

* Compressor: Single-stage axial, single-stage centrifugal
* Combustors: Annular, reverse-flow
* Turbine: Two-stage compressor turbine, two-stage power turbine

#### Performance

* Maximum power output: 1,217 kW (1,632 hp)
* Overall pressure ratio: 5.9:1
* Air mass flow: 6.2 kg/s (820 lb/min)
* Power-to-weight ratio: 3.74 kW/kg (2.27 hp/lb)