LCA Navy Mk2
Govt. of India sanctioned development of two LCA(Navy) Mk2 single seat Fighter prototypes (NP3 & NP4) under FSED Navy Ph-2. The LCA(Navy) Mk2 is being designed primarily to provide air defence to the fleet onboard Carrier and meeting all the mission objectives set out by the Indian Navy. Significantly
improved aircraft performance largely better than AF-Mk1 and integration of full suite of weapons are capabilities inherent in the design.
The main contributors to improvement in LCA(Navy) Mk2 have been identified as higher thrust engine, an increased wing area, an area ruled and streamlined configuration, lighter landing gear and structure, and improved systems layout towards better safety and maintainability. Flight control features to reduce approach speed even with an increase of around 2.5 tons of Carrier landing mass is a critical capability over LCA(Navy) Mk1. System Requirements Review (SRR) with participation of Indian Navy (IN) was carried out in detail with requirements capture and document prepared.
Concept design of LCA(Navy) Mk2 has been completed and detail design phase initiated. A detailed Preliminary Design Document for LCA(Navy) Mk2 has been prepared and provided to IN. Carrier compatibility requirements of INS Vikramaditya and INS Vikrant have been captured and necessary features incorporated in design. Based on requirement to consider wing folding to overcome the aft lift interference on INS Vikramaditya, a Technical Note was
prepared and submitted to IN. The note details rationale behind Wing outboard shift for LCA(Navy) Mk2. Issues in not opting for a wing fold and also restrictions in carrier take of mass if the wing is retained as in Navy Mk1 was brought out.
A meeting chaired by RM on 27 April 2016 was conducted at MoD, Delhi with participation of IN to review LCA(Navy) Mk2 Programme. IN had brought out
performance comparison of LCA(Navy) Mk2 with MiG-29K with respect to ASR/85. In order to improve aircraft performance dedicated task teams have been constituted working towards mass and drag reduction.
A comparative performance study of various naval combat aircraft was carried out with Airbus DS consultants and presented to stakeholders.
9.2.2 Design & Development Activities
(a) Aerodynamics & Configuration:
Air Vehicle Configuration of LCA (Navy) Mk2 is a critical activity during the concept design phase. The major activities carried out are:
Ø NMG V0.6L has been base lined for detail design
Ø Improving performance in terms of low supersonic wave drag, acceptable CG limits for stability and control criteria for zero ballast design.
Ø Optimized LEVCON & Shelf Flaps to achieve approach speed reduction for carrier landing.
Ø LEVCON converted into an active surface permitting operations with higher instability to achieve improved agility and performance.
Ø Ventral Airbrakes for performance with low interference
Ø Air intake redesigned for bigger GEF414-INS6 engine, with lip and cowl profiles and auxiliary doors optimized for superior performance at low speeds for
improved carrier launch capability.
Ø 1:10 scale low speed wind tunnel model fabricated at NAL and was tested in the HAL wind tunnel.
Ø Wind tunnel data correlation study with CFD simulation carried out and found to match very well.
Based on the iterations carried out in configuration performance evaluation was also computed to arrive at optimum solution. The major activities undertaken are:
Ø Installed performance estimation of new GE-F414-INS6 engine in LCA (Navy) Mk2 was carried out
Ø A comparative study on performance with contemporary Naval aircraft was carried out and shared with IN.
Ø Mission performance analysis for three IN profiles viz., Air Defence, Anti ship and Ground strike were carried out and has been established to meet the IN
requirements. Maximum capabilities in various IN defined missions to bring out margins available has also been evaluated.
(b) Airframe and Mechanical systems:
Preliminary Structure Layout with zero thickness model for NMG Version V0.06L for Front, Centre and Rear Fuselage incorporating 1020 mm longitudinal plug, 700 mm lateral plug. Concept studies of alternate Structural Layout for iterations on Inboards layout based on System requirement were undertaken.
Main Landing Gear (MLG) interface with Airframe has been defined. This involved studies for MLG load path and definition of structural attachment to fuselage. Structure layout for Nose Landing Gear (NLG) to suit the modified aircraft geometry is in progress. Arrestor hook structural integration concepts for different schemes were carried out. Finite Element Model (FEM) of Airframe was prepared and detailed stress analysis for critical carrier landing load conditions evaluated. As a result of this analysis it is found that the bending moment loads for most critical 2 point landing case on the fuselage is around 30% lesser than in Navy Mk1. This was identified as a potential weight reduction opportunity and a detailed study undertaken.
Fuel tank layout to meet increased internal capacity and c.g management has been defined to carryout detail design. The Airframe team took active participation in workshops and webex discussions with Airbus DS team at ADA to converge on a feasible structural design solution. Detail design of Airframe is in progress and CAD models/drawings are being created in concurrent design environment.
Landing gear & Arrestor Hook:
The MLG configuration of LCA (Navy) Mk2 with optimized structural interface made feasible by means of 350 mm additional space in the Y-direction of the aircraft has been finalized.
Following actions have been carried out:
Ø General Arrangement of Landing Gear System.
Ø Estimation of Landing Impact & Ground Manoeuvring Loads.
Ø Kinematics of Main Landing Gear & LG Doors
Ø Sizing of tyre and wheel size
Ø Kinematics of Nose Landing Gear & Doors has been updated to suit the new geometry V0.06L
Ø Arrestor Hook design as a conformal concept with Y-hook arrangement is being progressed by ARDC.
Ø Forcing function loads & Estimation of AHS Jack Loads has been carried out.
Higher thrust Engine GE-F414-INS6 is to be installed in LCA(Navy) Mk2. Updated Performance Cycle Deck(PCD) and CAD model of the Engine made available for design studies. ASMET and other qualification tests have been successfully completed by GE, USA and delivery of engines scheduled.
Top level requirements of fuel system was finalized with the involvement of Indian Navy. LCA(Navy) Mk2 is conceptualised with active fuel flow proportioner transfer system. The concept was finalized based on interface definition with interdisciplinary design teams. Fuel system design of LCA(Navy) Mk2 is supported by Airbus DS as part of engineering support in the Design Consultancy. Based on the above, Interface control documents for Fuel system with other systems that include Propulsion system, Avionics, Secondary Power System, Hydraulic system, structures, Environment Control System and Control law were prepared and provided to Airbus DS team for their comments and feedback. As an inherent feature of active fuel transfer system, pumps are installed in all fuel tanks. Electrical Power requirements in normal and emergency modes for this system was estimated.
Development activities initiated for procurement of smart fuel system components such as digital fuel gauging probe, optical level sensor, transfer pumps
with inbuilt pressure transducer and Nonreturn valves, intelligent line replaceable units(LRUs) for pressurization and venting system, etc., with original equipment manufacturer (OEM).
(c) Flight Control System and Control Law:
Preliminary Design Document for IFCS including IFCS Architecture released. Study of alternate configurations for Active LEVCON including Single / Multiple
Linear Actuators was carried out. TEX flap introduced for reducing approach speed which would provide ~5 knots speed reduction. Usage of available Electromechanical / Electro hydraulic actuators for Shelf flap is under finalization.
Control Law (CLAW):
Based on the configuration changes carried out in LCA(Navy) Mk2 and the Aero data provided by Aerodynamics group, simulations were carried out and based on results obtained, detailed interactions with Airbus DS consultants have been effective towards finalizing LCA(Navy) Mk2 configuration.
(d) Avionics & Weapon systems:
The Avionics architecture of LCA(Navy) Mk2 is to be adapted from the LCA-AF Mk2. Navy specific features are to be implemented based on interactions
currently in progress with Indian Navy. Feedback on AESA Radar and Communication interface has been received from IN. Network communications requirements has been sought from IN. Preliminary cockpit layout study for 19.8 Degree HUD has been carried out and feedback provided to CSIO, Chandigarh who are developing this LRU. Studies for integrating Automatic Carrier Landing System (ACLS) have been initiated with participation of IN.
Interaction with NEC, Mumbai, to capture EMI/EMC interface requirements on Carrier carried out.
(e) Test Facilities / Rigs:
Shore Based Test Facility (SBTF): The existing SBTF at Goa would be utilised for shore based testing of LCA(Navy) Mk2. Landing gear test rig: Development of test rigs to undertake full qualification of MLG & NLG and Nose wheel steering is planned.
Fuel System Rig: A fuel system test rig to evaluate the fuel system performance with emphasis on transfer sequence and its reliability is planned.
Iron Bird: Iron Bird-3 is planned to be set up at ARDC for qualification of FCS.
9.2.3 Airbus DS Design Consultancy
Quarterly workshops involving Aircraft design experts in major disciplines is in effect as part of Design Consultancy with M/s Airbus DS, Germany. The experts visit ADA for interactions with respective design teams. Based on the Design suggestions, design teams involving Aerodynamics, Structures and various groups have evolved Concept design of LCA (Navy) Mk2. ARDC, HAL as principal partner is involved in these design activities. The last 3 quarterly workshops (Total 11) planned as part of detail design phase has to be rescheduled and hence a requirement for PDC extension of this design consultancy
up to Dec 2017 is needed.
9.2.4 Follow Up Activities planned
a) Detail design of LCA(Navy) Mk2
b) High speed wind tunnel model fabrication and tests for force & moment and air intake
c) Development of Assembly Jigs
d) Raw material procurement
e) Fuel test rig