Thursday, December 24, 2020

Update On INS Arighat S-74 SSGN

Following the successful completion of the all-critical SCRAM systems tests and performance validations of the the third-generation OK-700A/VM-4SG pressurised water reactor (generating 89.2mW thermal/29.73mW electric and producing 18,000hp when using 44% enriched uranium) on board the Arighat S-74 SSGN, the stage is now set for the SSGN’s commissioning by next February.

SCRAM, also known as AZ-5 (referred to as A3-5 by Russia) is the process of the PWR’s emergency shutdown by immediately terminating the fission reaction through the insertion of control rods. For the INS Arihant S-73 and Arighat S-74, the Reactor Control & Protection System (RCPS) and the Control Rod Drive System (CRDS) were engineered back in the previous decade by the Control Instrumentation Division of BARC under the leadership of P.P. Marathe, while the applications software was developed by Dr. Usha Pal.

Built by ECIL, both the RCPS and CRDS, just like the Larsen & Toubro-developed integrated platform management system and battle damage control system, plus the TATA Power SED-developed ‘Saaraansh’ combat management system, all  make use of triple-redundant MIL-STD-1553B databus channels for functioning.

Wednesday, December 16, 2020

HAL's HTFE-25 Turbofan: Unclear & Unexplained R & D Objectives

It was in 2007 that US-based Honeywell successfully demonstrated to the Indian Air Force (IAF) the ‘drop-in installation’ of its F125IN turbofan on a Jaguar IS interdictor/strike aircraft. The F125IN delivers 30% higher thrust (27.7kN of dry thrust and 43.8kN with afterburning) than the Jaguar IS’ existing Rolls-Royce-Turbomeca Adour Mk.811 turbofan (rated at 25kN dry thrust and 37.5kN with afterburning), apart from offering improved pilot safety, lower maintenance costs and outstanding reliability. The turbofan’s modular construction and its integral dual full-authority digital engine control (FADEC) system can provide substantial savings (Rs.7,000 crore or US$1.5 billion) to the operator’s in life-cycle costs. Its time-between-overhauls (TBO) is 2,000 hours and its total technical service life (TTSL) of 4,000 hours, compared to the Adour Mk.811’s 1,200 hours and 2,400 hours.

In June 2009 Rolls-Royce successfully installed and tested the Adour Mk.821 turbofan (an uprated and upgraded derivative of the Mk.811) in a Jaguar IS to prove its capability and suitability to the IAF. However, the Mk.821 with a TBO of 2,000 hours and TTSL of 4,000 hours was being offered as a ‘low-cost’ upgrade and was thus bereft of some of the more advanced features found on the F125N.

An RFP for new turbofans with higher thrust was issued by India’s Ministry of Defence ( MoD) on November 26, 2010, to two turbofan manufacturers—Rolls-Royce and Honeywell. The RFP had specified a requirement for 200 turbofans estimated to cost around Rs.3,000 crore ($670 million)  Rolls-Royce later opted to withdraw from the competitive evaluations rather than be eliminated, resulting in a “single vendor situation”.

It was at this time that the MoD-owned Hindustan Aeronautics Ltd (HAL) decided to use its internal resources with the aim of producing an indigenously designed and developed non-afterburning turbofan within a timeframe of six years beginning from 2013. Designated as the HTFE-25 and rated at 25kN dry thrust, its engine core’s inaugural run was successfully completed in the presence of the then Defence Minister Manohar Parrikar at HAL’s Engine Division on December 14, 2015. Only two such engine cores had been built by then and even at that time no mention was made of this turbofan being developed for the Jaguar IS.

It was only in March 2019 that HAL decided to develop an afterburner for the HTFE-25 for giving it a maximum thrust of 40.39kN. However, HAL has not yet officially stated whether or not it will offer this variant of the HTFE-25 for the IAF’s Jaguar IS, about 80 of which are due to be re-engined. Nor has HAL provided any data on what will be the TBO and TTSL of an HTFE-25 turbofan fitted with an afterburner. It also remains unclear whether HAL will eventually be forced to seek technical consultancy expertise from the likes of Rolls-Royce for coming up with an optimally engineered production-series HTFE-25 turbofan meant for the Jaguar IS.