Turbomeca Turmo Explained

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 . 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 .^[1]

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.^[1]

Variants

Data from:-Jane's all the World's Aircraft 1957–58^[1]

Turmo I: The initial version of the Turmo; max continuous gearbox output at 3,000 rpm, at 33,750 rpm gas generator speed.

Turmo II:Developed version of the Turmo I; max continuous gearbox output at 34,000 rpm gas generator speed.

Turmo III:With 2-stage free power-turbine, pressure ratio 5.7:1 ;Maximum shaft output, max continuous at 33,400 rpm

Turmo IIIB:

Turmo IIIC:A 1200abbr=onNaNabbr=on turboshaft powering the Sud-Aviation Frelon prototypes.

Turmo IIIC₂: Developed from the IIIC delivering 1300abbr=onNaNabbr=on maximum output

Turmo IIIC₃: Maximum rating 1500abbr=onNaNabbr=on at 33,500 rpm for production Super Frelon helicopters

Turmo IIIC₄: Military variant.

Turmo IIIC₅:

Turmo IIIC₆:

Turmo IIIC₇:

Turmo IIID:Turboprop for the proposed Breguet Br 942 STOL transport, maximum rating 1225abbr=onNaNabbr=on.

Turmo IIID₂:1335abbr=onNaNabbr=on at 22,460 free turbine rpm

Turmo IIID₃:1450abbr=onNaNabbr=on 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 1800abbr=onNaNabbr=on 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^[1]

Further reading

• Book: Gunston, Bill . World Encyclopedia of Aero Engines . 1986 . Patrick Stephens . Wellingborough . 163 .

External links

• Turbomeca website

Notes and References

1. Book: Jane's all the World's Aircraft 1957–58 . Bridgman . Leonard . 1957 . Sampson Low, Marston & Company, Ltd . London.