Detailed description of D-18T engine

The engine modular design and highly developed monitoring and diagnosis system ensures its on-condition operation. The engine consists of 17 modules.

Modules of D-18T series 3 and 4 engines
01 – fairing nose 02 – fan wheel 03 – fan shaft with support 04 – fan casing 05 – fan stator blade 06 - IPC 07 - exhaust nozzle 08 – exhaust cone 09 – rear mount 10 – rear support 11 – fan turbine 12 - IPT rotor	13 – turbine bearing casing 14 – HPT rotor 15 – combustion chamber with HPT straightener 15.1 – HPT NGV 15.2 – combustion chamber 16 – reverser 17 – engine main module 17.1 – drive box 17.2 – intermediate drive

The D-18T three-shaft engine of a high bypass ratio has become the first in the USSR turbofan engine with a thrust of more than 20 000 kgf. 19.09.1980 - first start of a full-scale engine. 24.12.1982 - An-124 maiden flight. 19.12.85 – engine passed official bench tests. The D-18Т engine is also installed in An-225 Mriya aircraft. 188 units of engine are currently in operation. Total flight time is more than 1 million hours.

The An-124 Ruslan aircraft ensure up to 90% of market of unique, out-size, superheavy cargo air transportation. A development of Ruslan commercial operation, higher Customer’s requirements to the engine service life and fuel efficiency were resulted in a new improved engine version, D-18T series 3.

D-18T Series 3

Due to the undertaken design and technological efforts it was possible to improve the engine reliability, fuel efficiency and durability. If the first D-18T engines featured a service life to first overhaul of 500 hours, assigned service life of 1000 hours, for today’s D-18T series 3 engines an on-condition operation till serving out service life of main parts (with flight cycle of 4.5 hours and minimum service life of 5535 flight hours) is permitted by Aviation Register of Interstate Aviation Committee with its Supplement to Type Certificate No. 23-D/03 dated 19.02.1998. The works on a further improvement of the engine consumer’s characteristics are executed now.

D-18T Series 4

Structural differences of the D-18T series 4 engine compared to the D-18T series 3 engine are highlighted by color.

For improving a load-carrying capability and effectiveness of the An-124-100 aircraft a new modified engine version, designated as D-18T series 4, generating increased (~ by 10%) thrust at takeoff power rating was designed. For this the following efforts were introduced:

• fan with improved blade shaping which allowed to obtain higher takeoff thrust without increasing fan rotor rotational speed;
• updated fan turbine;
• thrust reverser with moving parts driven by two hydraulic motors, and electronic control (instead of mechanical drive and hydro-mechanical control system);
• efforts ensuring compliance of aircraft with ICAO, Part 4 requirements to noise;
• efforts concerning emissions-free exhaust for ensuring compliance with prospective ICAO norms;
• revised shaping of intermediate pressure turbine NGV;
• updated cooling system of HPT blades and NGV.

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