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Naval LCA - News and Discussion

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JayS
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Re: Naval LCA - News and Discussion

Postby JayS » 18 Apr 2017 18:37

shiv wrote:Thrust vectoring is a deliberate pre-designed add on an not an afterthought like car wedding decoration. Thrust that can move several thousand kg will blow away a thrust deflector unless there are some very powerful hydraulics to hold it steady in that exhaust airstream. All that adds weight.

A lot of Naval aircraft diverted their thrust downwards with zero weight addition by simply making the nosewheel longer so the plane looks like it is sitting on its ass, increasing the AoA while deflecting thrust down
Dassault Etendard
Image

A-7 Corsair

SeaHawk


This to increase AoA on the ground/deck, to facilitate lower TO roll.

Our own HF-24 marut also has similar stance on the ground.

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Re: Naval LCA - News and Discussion

Postby Kartik » 19 Apr 2017 02:30

LCA Navy Mk2 schematic

Image

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Re: Naval LCA - News and Discussion

Postby Kartik » 19 Apr 2017 03:11

ADA 2015-16 report. Filled with nuggets!

ADA Annual report 2015-2016

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Re: Naval LCA - News and Discussion

Postby Kartik » 19 Apr 2017 03:53

3 view of the LCA Navy Mk2 V0.06L

Image

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Re: Naval LCA - News and Discussion

Postby Indranil » 19 Apr 2017 04:13

Wow! There are so many things that I like about the Navy Mk2. The new forebody is very soothing to the eye. I had a hunch about what they were doing with the forebody, and that seems to be correct. Also, I think I see Uttam in there. I love the air intake design at the base of the fin (the current one is an eye sore).

Lots of details in the report. Please read it.

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Re: Naval LCA - News and Discussion

Postby srai » 19 Apr 2017 05:57

Kartik wrote:ADA 2015-16 report. Filled with nuggets!

ADA Annual report 2015-2016



...
9.2 LCA Navy Mk2
...
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.
...
A comparative study on performance with contemporary Naval aircraft was carried out and shared with IN.

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.
...


According to the excerpt above, NLCA Mk.2 will meet the IN's requirements (ASR/85). Since the IN is on the market for 57 foreign naval fighter, it would seem the IN's requirements have changed in the last year or so.

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Re: Naval LCA - News and Discussion

Postby Neshant » 19 Apr 2017 06:06

JayS wrote:Its more efficient to produce lift by using thrust to increase speed. Thrust vectoring is rather inefficient way of getting lift. None of the VTOL aircrafts have TV merely to assist it in STO. On contrary, STO is used to increase TOW when VTO is not a necessity. Basically Ramp is to help reduce need/extent of TV, and not the other way round.


The video shows an F-35 using thrust vectoring to do a short take off from a ramp. Would it be taking off any sooner if it had no TV?
The answer is surely a function of the load it carries, drag, angle of whatever..etc.
I am aware the redirection of some momentum from forward to downward entails a loss due to the conversion.

JayS wrote:And you cant just TV at the fag end of the jet. It will pitch up the jet violently.


We are in the age of self-attuning PID controls my man.
This isn't the case of a pilot cranking a hydraulic stick in the cockpit to vector the nozzle like he's flying a WWII plane.
What I'm thinking of is adaptive TV where the computer continuously calculates & adjusts the optimum vector angle as the aircraft moves down the runway.
The nozzle is not going to be stuck at angle theta all throughout the takeoff.
Rather the computer adapts the TV to the change - which i believe is what the F-35 does at all times.
The objective is to maximize both speed & lift by trading one for the other as needed.

JayS wrote:Plate deflectors are very inefficient. You will see high loss in thrust.


This would be just a proof of concept.
But before all this, someone needs to calculate whether this idea is even practical.

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Re: Naval LCA - News and Discussion

Postby sankum » 19 Apr 2017 07:29

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.


Come back carrier mass is 13T and will not be able to use aft lift of INS Vikramaditya?

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Re: Naval LCA - News and Discussion

Postby Indranil » 19 Apr 2017 09:53

Neshant,

Ever wondered why the Navy asked for a F-35C if thrust vectoring is the best way to take off using a short runway?

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Re: Naval LCA - News and Discussion

Postby shiv » 19 Apr 2017 11:06

Indranil wrote:Neshant,

Ever wondered why the Navy asked for a F-35C if thrust vectoring is the best way to take off using a short runway?

Maybe they did not do out of box thinking hain?

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Re: Naval LCA - News and Discussion

Postby JayS » 19 Apr 2017 12:23

Neshant wrote:
JayS wrote:Its more efficient to produce lift by using thrust to increase speed. Thrust vectoring is rather inefficient way of getting lift. None of the VTOL aircrafts have TV merely to assist it in STO. On contrary, STO is used to increase TOW when VTO is not a necessity. Basically Ramp is to help reduce need/extent of TV, and not the other way round.


The video shows an F-35 using thrust vectoring to do a short take off from a ramp. Would it be taking off any sooner if it had no TV?
The answer is surely a function of the load it carries, drag, angle of whatever..etc.
I am aware the redirection of some momentum from forward to downward entails a loss due to the conversion.

JayS wrote:And you cant just TV at the fag end of the jet. It will pitch up the jet violently.


We are in the age of self-attuning PID controls my man.
This isn't the case of a pilot cranking a hydraulic stick in the cockpit to vector the nozzle like he's flying a WWII plane.
What I'm thinking of is adaptive TV where the computer continuously calculates & adjusts the optimum vector angle as the aircraft moves down the runway.
The nozzle is not going to be stuck at angle theta all throughout the takeoff.
Rather the computer adapts the TV to the change - which i believe is what the F-35 does at all times.
The objective is to maximize both speed & lift by trading one for the other as needed.

JayS wrote:Plate deflectors are very inefficient. You will see high loss in thrust.


This would be just a proof of concept.
But before all this, someone needs to calculate whether this idea is even practical.


I said what I had to say. If you think its possible, then elaborate on idea, put up hard data/experimental results, anything. You are welcome to do that. Take it to "Design your own Aircraft" thread, perhaps. Because it ain't happening on NLCA. An idea in itself carries ZERO value in Engineering. It "how to execute" it that's what matters. You have an Idea, now try the second part. Who knows you might be able to get a patent for that and sell it to some OEM for good mullah. May be you can help IN put Su-30MKI on their AC since it already has TV and we are getting very powerful engines in Super-30 upgrade. Don't consider it as trolling. I am dead serious.

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Re: Naval LCA - News and Discussion

Postby JayS » 19 Apr 2017 12:25

Kartik wrote:ADA 2015-16 report. Filled with nuggets!

ADA Annual report 2015-2016


Many thanks for this link. I was trying to find it after someone put up 2014 and 2015 Reports in LCA thread, but couldn't.

It contains images of Ghatak. :D

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Re: Naval LCA - News and Discussion

Postby Marten » 19 Apr 2017 12:46

shiv wrote:
Indranil wrote:Neshant,

Ever wondered why the Navy asked for a F-35C if thrust vectoring is the best way to take off using a short runway?

Maybe they did not do out of box thinking hain?

Shiv saar, you apparently have much to learn about this whole business. To explain: If they had built a fully functional autonomous UFO UAV in their backyards, they would also have serious inputs based on out of the box thinking.
/OT

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Re: Naval LCA - News and Discussion

Postby sankum » 19 Apr 2017 13:44

Additional LCA Navy Fighter (NP6 & Np7): The cost element for the 3 additional aircraft (NP5, NP6 & NP7) has been provided by HAL and the cost committee duly constituted has had several discussions. This is expected to be finalised by end 2016. HAL has intimated that NP6 will be built in To +30 m and NP7 will be built in To +39 m, with To being CCS approval, followed by signing an MoU between ADA and HAL.


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.


2 more prototypes of NLCAmk1 and 5 knots approach speed reduction in NLCA mk2.

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Re: Naval LCA - News and Discussion

Postby JayS » 19 Apr 2017 14:43

sankum wrote:
Additional LCA Navy Fighter (NP6 & Np7): The cost element for the 3 additional aircraft (NP5, NP6 & NP7) has been provided by HAL and the cost committee duly constituted has had several discussions. This is expected to be finalised by end 2016. HAL has intimated that NP6 will be built in To +30 m and NP7 will be built in To +39 m, with To being CCS approval, followed by signing an MoU between ADA and HAL.


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.


2 more prototypes of NLCAmk1 and 5 knots approach speed reduction in NLCA mk2.


Actually 3 more prototypes for MK1. 2 for MK2. Initial plan was for 2 for MK1. But MP suggested one more trainer to expedite testing. So NP5. They have already funding for NP3/4. So this new proposal for NP5/6/7.

According to the AR, NP3 was due in Q1 2017. Its late already.

Also this shelf flap. Is it where I think it is..?? Trailing Edge Extension, the portion extending after wing TE till engine exhaust in the midline of rear fuselage...? AR does says so. Do we know any other aircraft having such "Shelf Flap"..? I had tried to find on google, but couldn't. It was mentioned in AR-2014 as well

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Re: Naval LCA - News and Discussion

Postby brar_w » 19 Apr 2017 18:29

JayS wrote:
Neshant wrote:
The video shows an F-35 using thrust vectoring to do a short take off from a ramp. Would it be taking off any sooner if it had no TV?
The answer is surely a function of the load it carries, drag, angle of whatever..etc.
I am aware the redirection of some momentum from forward to downward entails a loss due to the conversion.



We are in the age of self-attuning PID controls my man.
This isn't the case of a pilot cranking a hydraulic stick in the cockpit to vector the nozzle like he's flying a WWII plane.
What I'm thinking of is adaptive TV where the computer continuously calculates & adjusts the optimum vector angle as the aircraft moves down the runway.
The nozzle is not going to be stuck at angle theta all throughout the takeoff.
Rather the computer adapts the TV to the change - which i believe is what the F-35 does at all times.
The objective is to maximize both speed & lift by trading one for the other as needed.



This would be just a proof of concept.
But before all this, someone needs to calculate whether this idea is even practical.


I said what I had to say. If you think its possible, then elaborate on idea, put up hard data/experimental results, anything. You are welcome to do that. Take it to "Design your own Aircraft" thread, perhaps. Because it ain't happening on NLCA. An idea in itself carries ZERO value in Engineering. It "how to execute" it that's what matters. You have an Idea, now try the second part. Who knows you might be able to get a patent for that and sell it to some OEM for good mullah. May be you can help IN put Su-30MKI on their AC since it already has TV and we are getting very powerful engines in Super-30 upgrade. Don't consider it as trolling. I am dead serious.


Just to simplify - Sure as long as you have excess thrust you can redirect it and gain better short runway performance. This can be and has been explored and demonstrated on projects like the F-15 S/MTD and ESTOL. This obviously would add weight, complexity and require additional thrust to compensate which would increase design weight further on account of additional fuel - and on and on ..therefore making it a sub-optimal solution for a single engine light aircraft like the Tejas where they would be better off to seek ovreall T2W increase and thrust enhancements where performance is gained at minimum fuel consumption penalty as possible. That option is the F-414 Enhanced or a similar program for an alternative engine.

https://docs.google.com/viewer?url=pate ... 984229.pdf

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Re: Naval LCA - News and Discussion

Postby shiv » 19 Apr 2017 19:19

The value of a ski jump is basically to "throw the plane up" a bit. This is not as stupid as it sounds. Motorcycle and car stuntmen who use their vehicles to "jump" over rows of obstacles are also using this principle. If they drove straight into the obstacle they would flatten themselves against it. By going up the ramp they lose speed (at least they lose KE) but gain height and the momentum carries them through.

The plane on a ski jump has an added advantage. It has thrust that ensures that the loss of speed (or loss of KE) while climbing the ramp is compensated in part by the engine thrust, and the height gained is useful because any tendency for the plane to lose height after it goes off the edge is compensated by the increased speed, and therefore lift provided by descent. I don't know who discovered this but I think it was a serendipitous discovery.

Many of you may have seen my timepass video when I first read about this. I repost the link admitting that I have bad teeth, need dental attention; I am no engineer and have depended on videos all my life for education unlike brainy good teeth folks who read engineering books. One part of the video shows the model plane losing height but gaining speed to rise again after going off the edge of the "ski ramp"

https://www.youtube.com/watch?v=Nn_Yb1mySvo

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Re: Naval LCA - News and Discussion

Postby Indranil » 19 Apr 2017 21:11

I have always loved your videos Hakeem. I love one where you added a paper clip to a paper plane to explain how the movement of CG helps in the longitudinal stability of an airplaine. Brilliant.

But your explanation of this video is not quite right. It is not about energy conservation. Energy is conserved whether the projectile is straight or parabolic. What you are doing is giving the velocity a vertical component which allows you to fly just like a stone does till it returns to the same horizontal level. The distance covered during this flight is the increase in the runway length. The skijump is nothing but a mechanism to provide the vertical component at the end of the ramp.

The next logical question that anybody should ask is: We know that the longest range of a projectile is when the velocity vector is at 45 degrees to the horizontal. Why are ski jumps at 14 degrees then? That will bring us to the aerodynamics. Perhaps, a reason for a follow on video with a hot wheels car, your aircraft powered and unpowered at various degrees of the ramp ?

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Re: Naval LCA - News and Discussion

Postby Mihir » 19 Apr 2017 22:29

Indranil wrote:The next logical question that anybody should ask is: We know that the longest range of a projectile is when the velocity vector is at 45 degrees to the horizontal. Why are ski jumps at 14 degrees then?


The "45-degrees" reasoning is true only if the speed at which the projectile exits the ramp is the same for all angles. That assumption does not hold for a fighter taking off from a ski-jump.

Remember that changing the direction of an object in motion requires energy. The greater the change in direction, the more energy you expend in forcing that change (because the centripetal acceleration is greater). The energy loss is expressed as a drop in the magnitude component of the velocity vector, i.e. speed. So when the aircraft producing constant thrust leaves the 45-degree ramp, it would do so at a lower speed than one leaving a 14-degree ramp would. So perhaps 14 degrees is the angle that maximises the distance the aircraft is thrown.

Also, I wager there in't enough space for a 45-degree ramp that's gentle enough to not damage the aircraft.
Last edited by Mihir on 19 Apr 2017 23:41, edited 1 time in total.

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Re: Naval LCA - News and Discussion

Postby Indranil » 19 Apr 2017 23:02

That is a very good point and an oversight on my part.

There are aerodynamic reasons too. If the plane departed a 45 degree ramp while still not creating enough lift to support its weight, it will be flying at extremely high AoA. Lift generation, controlability and acceleration are all questionable.

In practice, they try to maintain an AoA lock after departure wherein Cl is very high and Cd is such that steady acceleration is possible to climb out airspeed.

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Re: Naval LCA - News and Discussion

Postby JTull » 20 Apr 2017 01:38

From what I can see:
NP3/4 are Mk2
NP5 is Mk1 trainer
NP6/7 are single seat Mk1

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Re: Naval LCA - News and Discussion

Postby Kartik » 20 Apr 2017 01:54

LCA Navy Mk2 program details. In-depth, posting it here so as to be able to refer back to it easily, as opposed to it being there in the report.

LCA Navy Mk2
9.2.1 Programme

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:
Airframe:
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.

Engine:
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.

Fuel Systems:
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

Neshant
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Re: Naval LCA - News and Discussion

Postby Neshant » 20 Apr 2017 07:03

Indranil wrote:Neshant,

Ever wondered why the Navy asked for a F-35C if thrust vectoring is the best way to take off using a short runway?



USN uses catapult launch which is the "best" way to take off from a short runway with a substantial load.

At least until the catapult malfunctions.

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Re: Naval LCA - News and Discussion

Postby Neshant » 20 Apr 2017 07:21

JayS wrote:I said what I had to say. If you think its possible, then elaborate on idea, put up hard data/experimental results, anything.


How can anyone provide hard experimental data when the experiment has not been conducted.
But before being conducted, it needs to be examined (by someone qualified) to see if it would in theory be practical.

May be you can help IN put Su-30MKI on their AC since it already has TV and we are getting very powerful engines in Super-30 upgrade. Don't consider it as trolling. I am dead serious.


I think it would an idea worth pursuing if we weren't just buyers of the plane with little knowledge of its intellectual content.
We can't even fiddle around with its settings during tests because its flight controls are a black box.
Russians would void all warranties on the plane since its not meant to be used off a carrier (i.e landing gear, salt corrosion, sea spray.. etc).

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Re: Naval LCA - News and Discussion

Postby Neshant » 20 Apr 2017 07:45

Mihir wrote: So perhaps 14 degrees is the angle that maximises the distance the aircraft is thrown.



I'm pretty sure the angle itself depends on the load of the aircraft, its approach speed, wind direction & strength..etc.
i.e. a one angle answer does not fit all scenarios for optimum lift during take off.

So here's another Earth shattering idea.

How about a carrier ski jump that varies its ramp angle to optimize conditions for the plane taking off?

Hydraulics move the ramp to a certain angle depending on the aircraft type & weight..etc and it gets mechanically latched into place.
So no, the hydraulic ramps need not be that powerful to hold up the weight of a plane. The latch mechanism does the holding up.

Its a case of moving the solution from the client side (aircraft TV or more powerful engine) to the server side (carrier with variable ramp angle). 8)

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Re: Naval LCA - News and Discussion

Postby shiv » 20 Apr 2017 08:48

Neshant wrote:
How about a carrier ski jump that varies its ramp angle to optimize conditions for the plane taking off?

Hydraulics move the ramp to a certain angle depending on the aircraft type & weight..etc and it gets mechanically latched into place.
So no, the hydraulic ramps need not be that powerful to hold up the weight of a plane. The latch mechanism does the holding up.

Its a case of moving the solution from the client side (aircraft TV or more powerful engine) to the server side (carrier with variable ramp angle). 8)

The moving ramp could have self attuning PID controls with adaptive mechanisms depending on environment and sensed weight of plane and its velocity.

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Re: Naval LCA - News and Discussion

Postby Gyan » 20 Apr 2017 09:07

I hope you can imagine the weight & complexity of such a system.

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Re: Naval LCA - News and Discussion

Postby shiv » 20 Apr 2017 09:30

Gyan wrote:I hope you can imagine the weight & complexity of such a system.

Me? Not at all. Someone else will have to do all that.. just sayin
Neshant wrote:But before being conducted, it needs to be examined (by someone qualified) to see if it would in theory be practical.

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Re: Naval LCA - News and Discussion

Postby Marten » 20 Apr 2017 09:31

shiv wrote:
Neshant wrote:
How about a carrier ski jump that varies its ramp angle to optimize conditions for the plane taking off?

Hydraulics move the ramp to a certain angle depending on the aircraft type & weight..etc and it gets mechanically latched into place.
So no, the hydraulic ramps need not be that powerful to hold up the weight of a plane. The latch mechanism does the holding up.

Its a case of moving the solution from the client side (aircraft TV or more powerful engine) to the server side (carrier with variable ramp angle). 8)

The moving ramp could have self attuning PID controls with adaptive mechanisms depending on environment and sensed weight of plane and its velocity.

Not to forget, parallel synchronized sensor fusion from outboard conformal synaptic networks with dynamic holo haptic input for the operators.

We need a more contemporary reimagining of our four-dimensional transitional hardware. We need to rethink the aerial horizontal paradigm to integrate administrative time-phases, ambient asset hardware to enable holistic mobility management.

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Re: Naval LCA - News and Discussion

Postby shiv » 20 Apr 2017 09:32

Marten wrote:
shiv wrote:The moving ramp could have self attuning PID controls with adaptive mechanisms depending on environment and sensed weight of plane and its velocity.

Not to forget, parallel synchronized sensor fusion from outboard conformal synaptic networks with dynamic holo haptic input for the operators.

We need a more contemporary reimagining of our four-dimensional transitional hardware. We need to rethink the aerial horizontal paradigm to integrate administrative time-phases, ambient asset hardware to enable holistic mobility management.

This would just be proof of concept

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Re: Naval LCA - News and Discussion

Postby Neshant » 20 Apr 2017 10:09

Draw bridges are not new.

The technology is hundreds of years old.

Never mind planes, trains literally go over them.

Image

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Re: Naval LCA - News and Discussion

Postby shiv » 20 Apr 2017 10:20

Neshant wrote:Image

OT but there is something wrong with this image or it is outdated tech. The bridge should go up just enough for what is underneath to pass rather than wasting energy going sky high when piddly boats pass underneath.. Imagine a bridge that goes up just enough to let a small ship pass and as it comes down the energy from gravity descent can be converted to charge batteries to raise the bridge next time. Of course for a big ship the bridge has to go all the way up - but then batteries get charged more as the bridge comes down.

The marvels of smart systems need smart people to come up with solutions to problems that might not even exist today

But this is the LCA Navy thread..

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Re: Naval LCA - News and Discussion

Postby jamwal » 20 Apr 2017 10:40

Marten wrote:
shiv wrote:The moving ramp could have self attuning PID controls with adaptive mechanisms depending on environment and sensed weight of plane and its velocity.

Not to forget, parallel synchronized sensor fusion from outboard conformal synaptic networks with dynamic holo haptic input for the operators.

We need a more contemporary reimagining of our four-dimensional transitional hardware. We need to rethink the aerial horizontal paradigm to integrate administrative time-phases, ambient asset hardware to enable holistic mobility management.


Are you MBA fatcat ?

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Re: Naval LCA - News and Discussion

Postby JayS » 20 Apr 2017 10:43

Indranil wrote:That is a very good point and an oversight on my part.

There are aerodynamic reasons too. If the plane departed a 45 degree ramp while still not creating enough lift to support its weight, it will be flying at extremely high AoA. Lift generation, controlability and acceleration are all questionable.

In practice, they try to maintain an AoA lock after departure wherein Cl is very high and Cd is such that steady acceleration is possible to climb out airspeed.
Mihir wrote:
Indranil wrote:The next logical question that anybody should ask is: We know that the longest range of a projectile is when the velocity vector is at 45 degrees to the horizontal. Why are ski jumps at 14 degrees then?


The "45-degrees" reasoning is true only if the speed at which the projectile exits the ramp is the same for all angles. That assumption does not hold for a fighter taking off from a ski-jump.

Remember that changing the direction of an object in motion requires energy. The greater the change in direction, the more energy you expend in forcing that change (because the centripetal acceleration is greater). The energy loss is expressed as a drop in the magnitude component of the velocity vector, i.e. speed. So when the aircraft producing constant thrust leaves the 45-degree ramp, it would do so at a lower speed than one leaving a 14-degree ramp would. So perhaps 14 degrees is the angle that maximises the distance the aircraft is thrown.

Also, I wager there in't enough space for a 45-degree ramp that's gentle enough to not damage the aircraft.


Both of you are correct. Its impractical to build ramp with 45deg exit, particularly when the ramp is parabolic in practice. imagine the distance it would take to reach 45deg. And when the plane departs the ramp, at 45deg AoA its basically a flying brick and it will drop dead unless the forward velocity component is very high and the plane attitude is brought rapidly (which is very unlikely given the control surfaces would be unresponsive at that AoA).

Fun-fact - F/A-18's HT is somewhat ineffective during CAT launch due to high angle flap deployment which completely blocks the HT. So they use Rudders to give Pitch-up. Both rudders turned inwards. This is used in flight as well at High AoA low speeds. Good that they have two canted tails. :wink:
Last edited by JayS on 20 Apr 2017 12:33, edited 1 time in total.

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Re: Naval LCA - News and Discussion

Postby Indranil » 20 Apr 2017 10:50

Neshant,

I actually like your questions. I am in a bit of a hurry today and will answer them tomorrow. Trust me there are very valid reasons for why things are done a certain way.

By the way, the harbour at mouth of the Chicago river just beyond these bridges is where they they trained thousands of airmen on makeshift flat tops during 1943. More than a 100 aircraft lie on the lakebed off the Chicago harbour. These bridges were present then. They would have considered it.

Jay,

I had read that about the F-18s below. Had forgotten. Thanks for refreshing my memory.

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Re: Naval LCA - News and Discussion

Postby Manish_P » 20 Apr 2017 12:35

jamwal wrote:
Marten wrote:Not to forget, parallel synchronized sensor fusion from outboard conformal synaptic networks with dynamic holo haptic input for the operators.

We need a more contemporary reimagining of our four-dimensional transitional hardware. We need to rethink the aerial horizontal paradigm to integrate administrative time-phases, ambient asset hardware to enable holistic mobility management.


Are you MBA fatcat ?


Or related to...

Image

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Re: Naval LCA - News and Discussion

Postby Neshant » 20 Apr 2017 13:17

Not that I am a fan of the 45 degree angled ramp but in theory you could have such a ramp.

The way to do it is an angled runway. Perhaps a 20 degree runway leading into a 45 degree ramp.

The plane would literally be travelling uphill for a takeoff however with huge loss of speed.

How about the reverse. The plane rolls down a 15 deg runway followed by a slight ski jump.

Speed is built up real fast going on a decline just like a truck rolling down a gentle hill.

The landing however has to occur in the opposite direction (i.e in the direction the carrier sails) which might be tricky for the pilot if he brings it down too hard.

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Re: Naval LCA - News and Discussion

Postby NRao » 20 Apr 2017 15:58

shiv wrote:
Neshant wrote:Image

OT but there is something wrong with this image or it is outdated tech. The bridge should go up just enough for what is underneath to pass rather than wasting energy going sky high when piddly boats pass underneath.. Imagine a bridge that goes up just enough to let a small ship pass and as it comes down the energy from gravity descent can be converted to charge batteries to raise the bridge next time. Of course for a big ship the bridge has to go all the way up - but then batteries get charged more as the bridge comes down.

The marvels of smart systems need smart people to come up with solutions to problems that might not even exist today

But this is the LCA Navy thread..


OT.

As a FYI.

Those bridges (in downtown Chicago) are counter balanced and therefore use very, very small amount of energy to move them. Also, by law, they have to move all the way up (for insurance purposes). Till then no river traffic can move under them.

How about a carrier ski jump that varies its ramp angle to optimize conditions for the plane taking off?


Not sure if you have checked. Russia's paper carrier uses their EMALS (TBD) and what appears to be a small ski jump. Actually on all fours cats, to the extent a bolster would encounter the ski jump too.

Next, an EMALS is an optimized cat. As optimized as you can get.
Last edited by NRao on 20 Apr 2017 16:07, edited 2 times in total.

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Re: Naval LCA - News and Discussion

Postby shiv » 20 Apr 2017 16:03

^^Does no one in this world get credit for coming up with solutions where the problem does not exist? I'm outta here.

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Re: Naval LCA - News and Discussion

Postby sankum » 20 Apr 2017 16:33

The aircraft is thrown up with the minimum required velocity so as to allow it to use thrust of engine and partial aerodynamic lift to accelerate to required velocity. If it is served by 14 degree ramp why 45 degree ramp is required. The vertical velocity imparted is= exit velocity sin14.

Take the case of NLCA at exit from ramp the MAX AoA of 19.5 degree is achieved in 2 sec after leaving ramp and maintained for 5 sec and then over next 5 sec reduced to optimum 12 degree. Just see the graph in the video linked earlier in the thread. The pitch angle is at max 24 degree just when the max AoA is reached.

Optimum solution for maximum performance.


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