GTRE GTX-35VS Kaveri

The GTRE GTX-35VS Kaveri is a low-bypass-ratio afterburning turbofan being developed by the Gas Turbine Research Establishment (GTRE), a lab under the DRDO in Bangalore, India. An indigenous Indian design, the Kaveri was intended to power production models of the HAL Tejas fighter, originally called the "Light Combat Aircraft" (LCA), but this plan was cancelled in September 2008. Further evolution of the Kaveri design and technologies is envisioned for armoured fighting vehicles and for ship propulsion.

Design

The Kaveri is a low-bypass-ratio (BPR) afterburning turbofan engine featuring a six-stage core high-pressure (HP) compressor with variable inlet guide vanes (IGVs), a three-stage low-pressure (LP) compressor with transonic blading, an annular combustion chamber, and cooled single-stage HP and LP turbines. The development model is fitted with an advanced convergent-divergent ("con-di") variable nozzle, but the GTRE hopes to fit production Tejas aircraft with a multi-axis thrust-vectoring version. The core Turbojet engine of the Kaveri is the Kabini, named after the Kabini River (which is a tributary of the Kaveri river).

The general arrangement of the Kaveri is very similar to other contemporary combat engines, such as the Eurojet EJ200, General Electric F414, and Snecma M88. At present, the peak turbine inlet temperature is designed to be a little lower than its peers, but this is to enable the engine to be flat-rated to very high ambient temperatures. Consequently, the bypass ratio that can be supported, even with a modest fan pressure ratio, is only about 0.16:1, which means the engine is a "'leaky' turbojet" like the F404.

The "Kaveri" engine has been specifically designed for the demanding Indian operating environment, which ranges from hot desert to the highest mountain range in the world. The GTRE's design envisions achieving a fan pressure ratio of 4:1 and an overall pressure ratio of 27:1, which it believes will permit the Tejas to "supercruise" (cruise supersonically without the use of the afterburner). The "Kaveri" is a variable-cycle, flat-rated engine and has 13% higher thrust than the General Electric F404-GE-F2J3 engines equipping the LCA prototypes.

Plans also already exist for derivatives of the "Kaveri", including a non-afterburning version for an advanced jet trainer, and a high-bypass-ratio turbofan based on the "Kabini" core. [Mama, Hormuz (November 1998). [http://www.bharat-rakshak.com/IAF/Info/Aircraft/LCA.html LCA Update] . "Flight International" via Bharat-Rakshak.com.] Another concept being considered is an enlarged version of the "Tejas" with two engines fitted with fully vectoring nozzles, which might make the vertical tail redundant (the "Tejas" has no horizontal tail).Gunston, Bill (Ed.) (June 15, 2006). "GTRE Kaveri" in "Jane’s Aero-Engines", Issue 14. Coulsdon, Surrey, UK: Jane's Information Group Limited. ISBN 0-7106-1405-5.]

An indigenous Full-Authority Digital Engine Control (FADEC) unit has been developed for the "Kaveri" (KADECU) by the Defence Avionics Research Establishment (DARE) of Bangalore. The Combat Vehicles Research and Development Establishment (CVRDE) of Avadi was responsible for the design and development of the "Tejas"' aircraft-mounted accessory gear box (AMAGB) and the power take-off (PTO) shaft.

History

Program

In 1986, the Indian Defence Ministry's Defence Research and Development Organisation (DRDO) was authorized to launch a programme to develop an indigenous powerplant for the Light Combat Aircraft. It had already been decided early in the LCA programme to equip the prototype aircraft with the General Electric F404-GE-F2J3 afterburning turbofan engine, but if this parallel program was successful, it was intended to equip the production aircraft with this indigenous engine.

The DRDO assigned the lead development responsibility to its Gas Turbine Research Establishment (GTRE), which had some experience in developing jet engines. It had developed the GTX37-14U afterburning turbojet, which first ran in 1977, and was the first jet engine to be designed entirely in India. A turbofan derivative, the GTX37-14UB, followed. The GTRE returned to turbojet technology with the greatly redesigned, but unsatisfactory, GTX-35.

For the LCA programme, the GTRE would again take up a turbofan design which it designated the GTX-35VS "Kaveri" (named after the Kaveri River). Full-scale development was authorised in April 1989 in what was then expected to be a 93-month programme projected to cost 382 crores (nearly US$82 million at the time).

Development

The original plans called for 17 prototype test engines to be built. The first test engine consisted of only the core module (named "Kabini"), while the third engine was the first example fitted with variable inlet guide vanes (IGV) on the first three compressor stages. The "Kabini" core engine first ran in March 1995. Test runs of the first complete prototype "Kaveri" began in 1996 and all five ground-test examples were in testing by 1998. The initial flight tests were planned for the end of 1999, with its first test flight in an LCA prototype to follow the next year. However, progress in the "Kaveri" development programme was slowed by both political and technical difficulties.

The embargo imposed by the U.S. following India's May 1998 nuclear weapons tests forced General Electric to suspend delivery of the F404 engines that were to power the prototypes after only 11 F404's had been supplied.Iype, George (March 2000). [http://www.rediff.com/news/2000/mar/14drdo.htm 'The LCA won't take off in the near future'] . "Rediff.com".] Alternative engines were considered — including the "Rafale's" SNECMA M88-2, the Eurofighter's Eurojet EJ200, and the RD-93 variant of the MiG-29's Klimov RD-33 — but no decision had been made by the time sanctions were lifted in September 2001. [Reddy, C. Manmohan (August 9, 2001). [http://www.hinduonnet.com/2001/08/09/stories/08090006.htm Saving the light combat aircraft] . "The Hindu".] In February 2002, the U.S. government agreed to supply an additional 40 F404-F2J3 engines to permit flight testing of several previously engineless LCA prototypes to begin. [Bedi, Rahul (December 17-30, 2005). [http://www.hinduonnet.com/fline/fl2010/stories/20030523001405100.htm Weighed down by history] . "Frontline".]

Problems

Little information has been publicly released to date concerning the nature of the "Kaveri"'s technical challenges, but it is known that the "Kaveri" has had a tendency to "throw" turbine blades, which required securing blades from SNECMA (as well as digital engine control systems). [Anon. (May 30, 2002). [http://webmag.safran-group.com/article.php3?id_article=100&lang=en Snecma Aerospace India: a new stage in cross-border collaboration] . SAFRAN Group website "Le Webmag". Retrieved from "Military Aviation and Defense" section September 14, 2006.]

Continuing development snags with the "Kaveri" resulted in the 2003 decision to procure the uprated F404-GE-IN20 engine for the eight pre-production Limited Series Production (LSP) aircraft and two naval prototypes. The ADA awarded General Electric a US$105 million contract in February 2004 for development engineering and production of 17 F404-IN20 engines, delivery of which is to begin in 2006.

In mid-2004, the "Kaveri" failed its high-altitude tests in Russia, ending the last hopes of introducing it with the first production "Tejas" aircraft. [Since India does not possess suitable aircraft, the high-altitude testing of the "Kaveri" is contracted to Russia, which uses a Tu-16 bomber for the purpose. Another "Kaveri" engine was delivered to Russia for further flight testing from June to September 2006, but on an Il-76 testbed instead of a Tu-16.] This unfortunate development led the Indian Ministry of Defence (MoD) to order 40 more IN20 engines in 2005 for the first 20 production aircraft, and to openly appeal for international participation in completing development of the "Kaveri". In February 2006, the ADA awarded a contract to SNECMA for technical assistance in working out the "Kaveri's" problems.Jackson, Paul; Munson, Kenneth; & Peacock, Lindsay (Eds.) (2005). "ADA Tejas" in "Jane's All The World's Aircraft 2005-06". Coulsdon, Surrey, UK: Jane's Information Group Limited. p. 195. ISBN 0-7106-2684-3.] At that time, the DRDO had hoped to have the "Kaveri" engine ready for use on the "Tejas" by 2009-10.

Current status

The Kaveri is still in development, and reports indicate that it will be ready to fly by 2009. Testing and certification for use on the Tejas is expected to take some more time after that. Till then, the first two squadrons of Tejas will be powered by the GE404 engine.

Scientific Advisor to Defence Minister M Natarajan said nearly 90 to 93 per cent of the expected performance had been realised and the government had recently floated an expression of interest to seek partners to move the programme further [ Anon. (February 5, 2007). [http://www.rediff.com/news/2007/feb/05iaf.htm] . Rediff news website. Retrieved from "Rediff.com" on May 15, 2007.]

DRDO has reportedly been able to develop single crystal blades, which represent a major technological achievement for engine development. Production and integrating this technology into the engine is expected to take some more time.

Kaveri has already undergone 1,700 hours of tests and has been sent twice to Russia to undergo high-altitude tests for which India has no facility. The engine is also being tested to power the next generation of Unmanned Aerial Vehicles. [ [http://www.outlookindia.com/pti_news.asp?id=544197 outlookindia.com | wired ] ]

In September 2008, it was announced that the Kaveri would not be ready in time for the Tejas, and that an in-production powerplant would have to selected. [cite news|url=http://www.hindu.com/2008/09/27/stories/2008092755480700.htm|title=Kaveri engine programme delinked from the Tejas|last=Sharma|first=Ravi|date=2008-09-27|work=The Hindu|accessdate=2008-09-28] Development of the Kaveri by the GRTE would continue for other future applications.

Development costs

Development of the "Kaveri" engine was projected in 1989 to cost Rs. 382.81 crores (nearly US$82 million). In Dec. 2004, it was revealed that the GTRE had spent over Rs. 1,300 crores (around US$295 million) on developing the "Kaveri". Furthermore, the Cabinet Committee on Security judged that the "Kaveri" would not be installed on the LCA before 2012, and revised its estimate for the projected total development cost to Rs. 2,839 crores (more than US$640 million). [Pandit, Rajat (July 16, 2006). [http://timesofindia.indiatimes.com/articleshow/1762012.cms IAF may not get to fly LCA before 2010] . "The Times of India".] The DRDO, however, currently hopes to have the "Kaveri" engine ready for use on the "Tejas" by 2009-10.

Criticism

The "Kaveri" program has attracted much criticism due to its ambitious objective, protracted development time, cost and time overruns, and the DRDO's lack of clarity and openness in admitting problems. Much of the criticism of the LCA program has been aimed at the "Kaveri" and Multi-Mode Radar programs.

There has been much criticism of the degree of realism in the DRDO's planning schedules for various elements of the LCA programme, most particularly for the "Kaveri" development effort. France's SNECMA, with over half a century of successful jet engine development experience, took nearly 13 years to bring the "Rafale" fighter's M88 engine to low-volume production after bench testing had begun; a similar timespan for the less-experienced GTRE would see "Kaveri" production beginning no earlier than 2009. [Reddy, C. Manmohan (September 16, 2002). [http://www.hinduonnet.com/thehindu/biz/2002/09/16/stories/2002091600190300.htm LCA economics] . "The Hindu".]

Another criticism has been DRDO's reluctance to admit problems in the engine and its resistance to involve foreign engine manufacturers until the problems became too large to handle.

= Kaveri Marine Gas Turbine (KMGT)=

GTRE has successfully developed the KMGT, a derivative of Kaveri engine for ships. [ [http://pib.nic.in/release/release.asp?relid=40470 Modified Kaveri Engine to Propel Indian Navy Ships] ] [ [http://www.domain-b.com/defence/def_prod/20080717_kaveri_engine.html Breakthrough for GTRE scientists – develop marine version of the Kaveri engine news] ]

Applications

* GTX-35VS "Kaveri":
** HAL Tejas (planned for production models)
** HAL Medium Combat Aircraft (conceptual)
** Unmanned Aerial Vehicles
* Derivatives:
** The Indian government plans to adapt and further develop the "Kaveri" engine design and technology to create a gas-turbine powerplants for armoured fighting vehicles such as the Arjun tank”

pecification (GTX-35VS "Kaveri")

jetspecs

type=Afterburning turbofan
length=137.4 in (3490 mm)
diameter=35.8 in (910 mm)
weight=2,427 lb (1,100 kg) [Production model goal: 2,100 lb (950 kg)]
compressor=two-spool, with low-pressure (LP) and high-pressure (HP) axial compressors:
*LP compressor with 3 fan stages and transonic blading
*HP compressor with 6 stages, including variable inlet guide vanes and first two stators
combustion=annular, with dump diffuser and air-blast fuel atomisers
turbine=1 LP stage and 1 HP stage
fueltype=
oilsystem=
power=
thrust=
*"Military thrust (throttled)":11,687 lbf (52.0 kN)
*"Full afterburner":18,210 lbf (81.0 kN) [Goal: 20,200 lbf (90.0 kN)]
aircon=
fuelcon=
specfuelcon=

*"Military thrust": 0.78 lb/(lbf•h) (79.52 kg/(kN·h))
*"Full afterburner": 2.03 lb/(lbf•h) (207.00 kg/(kN·h))
power/weight=
thrust/weight=7.8 (76.0 N/kg)

Engine cycle

*Airflow: 172 lb/s (78.0 kg/s)
*Bypass ratio: 0.16:1 (i.e., "leaky" turbojet)
*Overall pressure ratio: 21.5:1 [Goal: 27:1]
*LP compressor pressure ratio: 3.4:1 [Goal: 4:1]
*HP compressor pressure ratio: 6.4:1
*Turbine entry temperature: 2,218-2,601 °F (1,214-1,427 °C; 1,487-1,700 K) [Goal: 3,357 °F (1,847 °C; 2,120 K)]

ee also

* Gas Turbine Research Establishment(GTRE)
* List of aircraft engines
* List of aircraft engine manufacturers

References

External links

* [http://www.drdo.org/products/kaveri.htm "Kaveri" product detail on DRDO website]
* [http://frontierindia.net/kaveri-engine-gathers-momentum/ Kaveri engine gathers momentum]