Naval LCA - News and Discussion

[Neshant]

These kind of carrier fixes are FAR easier and simpler to do, rather than fix the airplane and demand more off performance and make it grossly overpowered. Also, the greater t.o runway length also opens the possibility of putting stuff like Hawkeye AEW on the carrier and also supply and aerial refuelling assets and they could operate from both the VikAd and the Vikrant with full capability.

Are you sure just another 20 meters is all that's needed for the Tejas MK2 to take off with a sizeable load?

If that's all it takes, extending the runway by whatever means should be the #1 priority before they put this ship through its trials.

It surely cannot be that difficult of a task to find/create an additional 20 meters.

[JayS]

How practical would it be to modify Vikramaditiya and install a catapult take off. (EMALS or steam)

I know it will delay the program further, but by how long.

I'm talking about buying the turn-key system from the US and installing it. Not doing a 10 year R&D on how to build an indigenous catapult.



The deck would have to be ripped up. But once completed, the added benefit is VikA could launch planes with heavier payloads. e.g Hawkeye sized planes.

Unfortunately it does not have very much space to store these larger planes on board.

Russians took 10 years to modify the Gorshkov into a plane carrier.

I don't think Steam CAT is compatible with ramp. it could be installed on the flat portion before the ramp. But EMALS is said to be compatible with curved ramp as well. Also EMALS should be much more compact. A Steam CAT will have steam cylinders, huge steam boilers and all associated mechanical systems going under the deck. Plus you would need additional power given by the powerplant of the ship to run the CAT or EMALS. I think, even if possible, it would be rather difficult to retrofit VikAd with CAT now. You have to design and build the ship ground up for it. EMALS could still plausible but steam CAT is a big no IMO. VikAd is simply too small.

We better build another ship as CATOBAR from ground up. Anyhow right now we need VikAd since its the only operation AC we have. We cannot afford to have it sent for huge retrofit which may take a decade for retrofit and sea qualification trials, given we don't know a whole lot about CAT. We should start building another copy of Vikrant (may be little longer) before we go for a CAT/EMALS based AC, which is gonna take quite a while and extensive outside help.

[JayS]

These kind of carrier fixes are FAR easier and simpler to do, rather than fix the airplane and demand more off performance and make it grossly overpowered. Also, the greater t.o runway length also opens the possibility of putting stuff like Hawkeye AEW on the carrier and also supply and aerial refuelling assets and they could operate from both the VikAd and the Vikrant with full capability.

Are you sure just another 20 meters is all that's needed for the Tejas MK2 to take off with a sizeable load?

If that's all it takes, extending the runway by whatever means should be the #1 priority before they put this ship through its trials.

It surely cannot be that difficult of a task to find/create an additional 20 meters.

VikAd's ramp is also 13deg and shorter (at 45m I think) compared to the one on Vikrant with 14deg and 67m (length number might be slight off, don't remember exactly, but can be found in Navy RFI for 57 new jets).

[vina]

VikAd's ramp is also 13deg and shorter (at 45m I think) compared to the one on Vikrant with 14deg and 67m (length number might be slight off, don't remember exactly, but can be found in Navy RFI for 57 new jets).

It is easy to find out for yourself (i haven't done it .. i just took the numbers posted here). You have the top view of both the VikAd and the Vikrant. You know the lengths of the ships and from the image, you can calculate what is the max runway length for both . All it needs is scale and 2 seconds.

Also work backwards.. You need 215m for the long take off length (for full load) . So find out where will you position the chocks best given the layout we have in both the ships.

That should take care of all the "thrust" and whatever shortfalls the folks here are complaining about the NCLA MK1 and take care of any potential shortfalls in Mk2 as well

[vina]

before they put this ship through its trials.

one can 'Jumbo-ize' a ship

Facepalm! Which ship has a "problem" and why ?

[Neshant]

it would be rather difficult to retrofit VikAd with CAT now.

We better build another ship as CATOBAR from ground up.

Whoever designed the VikA did a half-ass job of it.

Sadly this will remain a dream for a while.

[tsarkar]

With regards to Polynesian vs Roman, the sail material from Pandanus also enabled flexibility in exploiting various points of sail unlike flax/cotton used by Romans / early Europeans that also rotted in heat, humidity & salinity very quickly. Improvements in materials enabled later sailing innovation.

https://en.wikipedia.org/wiki/Pandanus

Steam Catapults are maintenance intensive with bulky and heavy under deck equipment not suitable for small/medium ships with larger aircraft sizes and associated fuel, ordnance and spares competing for space. Biggest problem is transients - uncontrolled power surges - that reduce airframe life and increase ship maintenance.

Steam for catapults can be produced in boilers irrespective of whether the prime mover is ST, Diesel, GT or Nuclear. Electricity for catapults too can be generated irrespective of whether the prime mover is ST, Diesel, GT or Nuclear.

Vikramaditya is a cruiser hull from Day 1, so cannot be miraculously transformed - and hence IN disinterest right from the start.

The Vikramaditya re-build and Vikrant build started much before NLCA Mk1 performance parameters were arrived at via testing at SBTF.

Vikrant modifications will take testing and time - about the same duration it took to re-design Vikramaditya.

If one has a proven ship design - aircraft are designed/purchased around it. If one has a proven aircraft design, then ships are designed around it.

Depends on what you have first. In our case, the aircraft carriers came first.

https://www.gemarinesolutions.com/conte ... th-frigate

https://www.indiannavy.nic.in/content/c ... 0%98-kochi

The assessments based on SBTF testing would've been carried out before taking a decision.

[tsarkar]

The naval LCA has to be made to work.

While I wholeheartedly support the principle of indigenous naval fighter and validating the control laws, physics and engineering have their limits too.

https://en.wikipedia.org/wiki/General_D ... man_F-111B

The weight goals for both F-111 versions proved to be overly optimistic. Excessive weight plagued the F-111B throughout its development. The prototypes were far over the requirement weight. Design efforts reduced airframe weight but were offset by the addition of the escape capsule. The additional weight made the aircraft underpowered. Lift was improved by changes to the wing control surfaces. A higher thrust version of the engine was planned. During the congressional hearings for the aircraft, Vice Admiral Thomas F. Connolly, then Deputy Chief of Naval Operations for Air Warfare, responded to a question from Senator John C. Stennis as to whether a more powerful engine would cure the aircraft's woes, saying, "There isn't enough power in all Christendom to make that airplane what we want!"

http://www.nytimes.com/1996/06/09/us/th ... -dies.html

With his answer . . . Admiral Connolly's dream of promotion to full admiral died along with it.

Read the bio in the obituary, he was from MIT.

[JayS]

it would be rather difficult to retrofit VikAd with CAT now.

We better build another ship as CATOBAR from ground up.

Whoever designed the VikA did a half-ass job of it.

Sadly this will remain a dream for a while.

It was not designed as an AC from scratch. It was always gonna have limitations.

In that video at 4-5sec one can notice sudden pitch up that the AI seminar was pointing to.

PS: Just saw that tsarkar already explained that part about VikAd.

[JayS]

Wild thought - Can't the NLCA take a slightly curved path in the initial TO roll so that it starts from the point where there is a circle on landing strip, (but as outward as possible towards portside edge) in following pic..???

If it completes the turning in the initial phase where the speed is still below a threshold where it will not roll and topple, that could give additional few meters for TO perhaps..?? Since it will be autonomous TO, FCS can take care of the turning.

Why could this not be done..?? any thoughts?

Or why can't they just extend the line that is shown for shorter TO roll all the way back as far as possible..?? That's also will give more distance.

VikAd Schematic

.

[sankum]

Data from Defexpo 2001 mig 29 prototype could fly from 110m runway on carrier with 18.55T with 650Kg payload and from 190m with 22.4T with payload of 4.5T with 16.6 T thrust engines.

Mig29k has larger wing and take off mass of 24.5T with 5.5T ( with 18T thrust )payload from full length runway on INS Vikramaditya and it can be safely inferred that from 125m runway it can take off with more than 20.5T i.e more than 1.5T payload and full internal fuel of 4.8T.

INS Vikramaditya ramp length is of 55m.

[vina]

Hmm. I was wondering how it would work if the VikAd is "modified" this way. Extend the flare /overhang in the stern to the area marked in yellow and had the "long " take off position as shown, with a plane there.

For the "short" take off, move that close to the arrester wires (I have shown a plane in the approx position) , or even behind (like they did in the Vikrant) . This way, you get an increase in take off run by approximately 30 metres or so ..for 230/240 for the "long run" and roughly 215 m for the "Short" run. That will give ample margin to take off in any maximal corner condition and can easily host an E2D Hawkeye.



I mean , unlike a catapult, you can install jet blast deflectors and chocks pretty much anywhere on the deck as suits an aircraft. You are not constrained by the catapult installation etc. If the current take off runs are optimised for Mig29K in partial load and full load conditions (are they ?), and if the LCA and E2D needs additional length, just add more take off points as shown. After all the blast deflectors and the chocks retract flush into the deck and are no hindrance to aircraft movement.

[NRao]

Vina ji,

The IN had declined, in 2007, to accept the offer for E2D, for the Vicky, because the US could not guarantee a single engine take off if one engine failed. So, unless a run can give it the same speed as a Cat, do not think it is viable. So, does your design offer the same params as a Cat? It has to overcome the one engine take off issue for it to accepted.

The E2D, IIRC, had managed a low angle ski jump - cannot recall any details - in the 80s.

[vina]

Vina ji,

The IN had declined, in 2007, to accept the offer for E2D, for the Vicky, because the US could not guarantee a single engine take off if one engine failed. So, unless a run can give it the same speed as a Cat, do not think it is viable. So, does your design offer the same params as a Cat? It has to overcome the one engine take off issue for it to accepted.

The E2D, IIRC, had managed a low angle ski jump - cannot recall any details - in the 80s.

With a ski jump, if one engine fails, you eject. Whether it is E2d or mig29 or whatever is immaterial. You sacrificed that when you went with ski jump.

[NRao]

i do not know - did not google before posting - but, doubt one can eject from a e2d.

Anyways, i think e2d on a ski jump is not part of the IN thought process.

ALL that (E2D, V-22 (actualy, perhaps the Future Vertical Lift (VFL) (offered to India via the DTTI as JV)), etc, etc, etc.) should come into play in the Vishal+.

Sorry for the diversion. Please continue.

[Cain Marko]

Ok. NLCA MK2 - Off Vikrant & VikAd
Assumptions - 8.0 tons empty wt. Internal fuel 3.5 tons, Installed thrust @ IS+20 - 95KN , take off run 213 m

MTOW under the above conditions is 16.2 Tons (the Gripen NG has an MTOW of 16.5 tons for comparison) .
Payload - 4.68 tons.

The NLCA Mk2 is a clear replacement for the Mig 29K .[/b].

That there is a mighty big assumption - the IAF LCA Mk2 will probably make that weight or a bit less, one look at the 8 ton Gripen NG is a good reminder. The NLCA will be closer to 9 tons is my guess. So keeping this in mind, your numbers will change significantly. Max payload will be around 3.5 tons. The MiG-29k is about 5.5 tons.

[Neshant]

Hmm. I was wondering how it would work if the VikAd is "modified" this way. Extend the flare /overhang in the stern to the area marked in yellow and had the "long " take off position as shown, with a plane there.

The structure would have to take the weight of 25 tons minimum.

It does not sound like a good idea to add on a structure with no real support underneath except for pillars attached to the sides of the ship holding it up.

A couple of planes, weapons, towing vehicle, and other stores might be stationed on top of it at any given time.

They did a poor job of requirements engineering when building this carrier having not captured requirements of all stake holders properly.

[Neshant]

Wild thought - Can't the NLCA take a slightly curved path in the initial TO roll so that it starts from the point where there is a circle on landing strip, (but as outward as possible towards portside edge) in following pic..???

Original requirements were such that :

1) a helicopter has to be able to land/take off at the same time as
2) one plane is taking off
3) and one plane is landing

All 3 activities have to be possible at the same time.

Maybe they can dispense with that requirement.

[JayS]

Wild thought - Can't the NLCA take a slightly curved path in the initial TO roll so that it starts from the point where there is a circle on landing strip, (but as outward as possible towards portside edge) in following pic..???

Original requirements were such that :

1) a helicopter has to be able to land/take off at the same time as
2) one plane is taking off
3) and one plane is landing

All 3 activities have to be possible at the same time.

Maybe they can dispense with that requirement.

How is that possible...? At max you can have one heli landing/taking off while there is fighter taking off from shorter run. While fighter landing all other activities has to be on hold since there is overlap of other things with landing strip.

[shiv]

Original requirements were such that :

1) a helicopter has to be able to land/take off at the same time as
2) one plane is taking off
3) and one plane is landing

All 3 activities have to be possible at the same time.

Any source other than yourself for this information?

[chola]

it would be rather difficult to retrofit VikAd with CAT now.

We better build another ship as CATOBAR from ground up.

Whoever designed the VikA did a half-ass job of it.

Sadly this will remain a dream for a while.

VikA is a rework of a goddam Minsk class which are STOVL cruisers. There is only so much you can do while refitting it. Adding length to an existing hull is impossible.

[Cybaru]

Any source other than yourself for this information?

Since january of this year, its a perfectly legal to circularly reference yourself! Even presidents are doing it!

[Marten]

Any source other than yourself for this information?

Since january of this year, its a perfectly legal to circularly reference yourself! Even presidents are doing it!

No different from building backyard drones and integrating Alexa to claim upper hand in technology strategee.
We have had only two such experts -- would expect both of you amateurs to yield to such expertise.

I don't think any carrier world wide would support concurrent (not just simultaneous) take off and landing. It has been tried at INS Kodihalli docked off Karela in Bengaloor. The heli takeoff was dicey to say the least. /ot

[Neshant]

It was mentioned in an article just prior to or during the early construction of the carrier. It was about various design options that were examined for the carrier.

I don't have reference to the article since this was a few years ago.

It mentioned several options from synchronized to simultaneous takeoffs and landings.

It is certainly possible to take off and land with STOL if the carrier planes are Harriers. They don't need as long a runway as the Mig-29K and don't have to be as far back.

[NRao]

All take off and landing spots have to be marked, for fixed and rotory crafts - anywhere, but especially on a boat.

Vicky. The circles are for helos or Harriers, by type.



So, I suspect, a -29 can take off and a helo (or two?) Could potentially operate at the tail end.

But landing is exclusive. On the Vicky.

[Neshant]

I don't think any carrier world wide would support concurrent (not just simultaneous) take off and landing.

Planes can easily land and take off on carriers at the same time.

Take a look at China's newest carrier.

Their helicopter deck at the back is long and has enough clearance for 2 planes taking off, 1 plane landing and 1 helicopter readying for takeoff all at the same time.

VikA's runway is short and it can only do 1 take off and 1 landing.

Goshkov was a good deal for what it offered until it was realized the Russians low balled the price and began extorting a whole lot more.

Take any Russian quote and double it for the final amount to be charged as contracts mean nothing to them.

[shiv]

Planes can easily land and take off on carriers at the same time.

Trolling bluff. Simply not done for safety reasons. The oblique landing path is not for simultaneous landing and take off but so that the ship will not sail over the plane if it ditches on landing.

[Neshant]

If only 1 plane can land or take off at a time, all that would be needed is one runway not two.

You can see for yourself where the planes take off from

[shiv]

If only 1 plane can land or take off at a time, all that would be needed is one runway not two.

You can see for yourself where the planes take off from
]

The only thing missing from the equation is your own ignorance sir. I tried to give you a hint - but you are intent upon making wild, and I repeat, ignorant guesses based on images. I normally do not read your posts but I will punish myself for reading them by replying

There is a reason for having planes take off in the forward direction and planes land obliquely. You will see this on every aircraft carrier and it has nothing to do with "simultaneous take off and landing" Oblique path is never used for take off with good reason

Planes taking off without a full runway need as much headwind as possible so ships sail into the wind at full speed for takeoff and the planes take off into the wind - which is blowing from the direction the ship is going. A ship sailing at 25 knots into a 10 knot wind gives and extrat 60 kmph wind to help the plane take off

When planes are landing they must catch the arrestor wires. if by chance they do not catch the wire the pilot needs to be ready to take off and fly around. In rare instance the plane is in trouble and cannot take off. it will then ditch into the ocean right in front of the carrier. If the plane ditches under the bow the ship will crush the plane. Ditching on the side saves the plane and the pilot can be rescued.

Speaking of rescue - there is one more important reason. There is ALWAYS a helicopter hovering for rescue and all resources on board - including deck crew and control are are concentrated on one aircraft at a time in case there is an emergency. Having one plane approaching for landing and the other trying to take off divides the resources and this is not done.

Yes there may be situations in which planes have taken off and landed almost simultaneously but the is not a planned routine and is most likely on US ships. And yes planes taking off have, on occasion fallen right in front of the carrier. There are stories but you will probably not bother reading - so I am "simply posting"

[NRao]

USN carriers perform simultaneous take-off landings - YT has vids. One needs a larger carrier and *experience* to do this on a regular basis - not a trivial operation.

The angled deck was to accommodate (fast) jet plane - so that they could "bolt" if need be.

BTW, a simultaneous takeoff:

[Neshant]

Simultaneous does not mean they take off at the exact same time.

The video I posted shows 2 aircraft on the ready for take off at the forward deck. They can take off in under 30 seconds of each other.

They are no where near the runway at the rear which is available for for landing and takeoff.

[shiv]

USN carriers perform simultaneous take-off landings - YT has vids. ]

Please post link

[NRao]

Depends on which cat they use to take-off. IF they line up on a cat that is next to each other, then they cannot take-off together and they need sufficient time for the first craft's wash to clear.

The picture I posted in my previous post, shows two planes taking off together, which they could afford to do so because they are at 9 deg offset AND they bank (which is what that picture actually is meant for).

USN planes using the starboard cats allows planes to land at pretty much teh same time - they have ot have offsets because of regulations.

[shiv]

Do you have any videos of simultaneous take_off_AND_landing? That is what I am referring to. A carrier with two catapults is designed for simultaneous takeoffs. But we are talking about takeoff AND landing simultaneously which is what started me off.

[JayS]

Do you have any videos of simultaneous take_off_AND_landing? That is what I am referring to. A carrier with two catapults is designed for simultaneous takeoffs. But we are talking about takeoff AND landing simultaneously which is what started me off.

At least I never seen anything like that. Even if its physically possible its too dangerous to do it in practice. I see no damn reason why it needs to be done. An aircraft can easily be hold on for landing for few minutes until all aircrafts are launched and the deck is clear. They have a lot of fuel. And if its emergency landing then TO can be held for few min. If aircraft is already on CAT it take less than a min to launch it. So deck can be easily cleared on short notice. No big deal.

Also Remeber its not just the aircrafts on the TO roll there are follow on loaded jets waiting for their turn which are occupying landing strip too perhaps. And personnel working on the deck.

There is no good reason for having an SOP for simultaneous landing and TO of fighters. Maybe if KK Menon from Ghazi Attack was AC commander he might have ordered such thing on his Ship.

[Neshant]

The downside of EMALS.

1. It can ruin airframes.
2. It cost a LOT.
3. At least 2 are needed.

The US Department of Operational Test and Evaluation (DOTE) revealed yesterday, in its end-of-year report [PDF] for financial year 2016, that the EMALS fitted to the new nuclear-powered carrier USS Gerald R. Ford put "excessive airframe stress" on aircraft being launched.

Lewis Page, late of this parish, summed up what happened when the government tried to exercise that option: "... it later got rescinded, on the grounds that putting catapults into the ships was not going to cost £900m – as the 2010 [Strategic Defence and Security Review] had estimated – but actually £2bn for [HMS] Prince of Wales and maybe £3bn for Queen Elizabeth. This would double the projected price of the two ships."

https://www.theregister.co.uk/2017/01/1 ... ld_r_ford/


Before the design of naval MK2 is frozen, they should decide if they want to install EMALS on Vishal.
That decision will influence the design of naval MK2 itself.

Conventional carriers can launch up to 3 aircraft in quick succession (within seconds of one another) to intercept incoming threats.
To match that, at least 2 EMALS are needed as seen in the Queen Elizabeth EMALS concept design.

[JayS]

The downside of EMALS.

1. It can ruin airframes.
2. It cost a LOT.
3. At least 2 are needed.

The US Department of Operational Test and Evaluation (DOTE) revealed yesterday, in its end-of-year report [PDF] for financial year 2016, that the EMALS fitted to the new nuclear-powered carrier USS Gerald R. Ford put "excessive airframe stress" on aircraft being launched.

That

Lewis Page, late of this parish, summed up what happened when the government tried to exercise that option: "... it later got rescinded, on the grounds that putting catapults into the ships was not going to cost £900m – as the 2010 [Strategic Defence and Security Review] had estimated – but actually £2bn for [HMS] Prince of Wales and maybe £3bn for Queen Elizabeth. This would double the projected price of the two ships."

https://www.theregister.co.uk/2017/01/1 ... ld_r_ford/


Before the design of naval MK2 is frozen, they should decide if they want to install EMALS on Vishal.
That decision will influence the design of naval MK2 itself.

Conventional carriers can launch up to 3 aircraft in quick succession (within seconds of one another) to intercept incoming threats.
To match that, at least 2 EMALS are needed as seen in the Queen Elizabeth EMALS concept design.

What is conventional carrier..?? Why only three aircrafts..?? how 2 EMALS will match quick launch of 3 jets exactly..??

Is USS Nimitz class a conventional AC..??

[brar_w]

The argument is not really valid. Of course CAT's will have a cost but using the QE design changes as an example isn't accurate since it is factored in a design modification since they were in advanced stages of development already. I've provided the exact Firm Fixed Priced contract cost for the EMALS on the first 3 USN CVN's. Same with DOTE reports which are always by their very nature transitionary and only go to show the state as it existed at the time the report was written (months before it was actually published). It usually does a poor job of documenting fixes in the work to most problems nor do they devote extensive space in their future report to corrective measures undertaken to fix deficiencies cited in earlier reports.

That was the classic MO of the previous DOTE..But regardless all CAT's including steam ones will create stresses on an airframe not seen during ski ramp launches. On this is one way to launch heavy payloads and large manned and unmanned aircraft. EMALS and AAG glitches will be fixed on the first in class vessel..That is what the extended air wing test period is for even though they have triple digit launches of aircraft (literally all types) on land using the carrier configuration EMALS. If the IN exercises the EMALS option, by the time it gets its first carrier there should be 4-5 EMALS fitted operational CVN's.

[Prasad]

CAT specific design is being worked upon in parallel. Soooo not really a problem there.

[shiv]

Don't know how much relevance it has to the LCA Navy takeoff speed and rotation but I thought this was a generally informative video
https://www.youtube.com/watch?v=7p8Pqna4t7c