Future russian aircraft carriers. #3

hurray! we have already two specialists here better than the whole OAK!!! and VVS decision makers

Yak is the only portion of OAK that wants STOVL designs... I am sure all other bureaus would prefer to keep it simple and not need to bother with engines powerful enough to get a fighter supersonic and at the same time a nozzle that deflects its thrust 95 degrees so it can land or take off vertically.

Kamov would probably prefer the new aircraft to be a helicopter... are they wrong?

wait the WTF do you need those big big carriers for?

Because smaller carriers have limited performance and endurance.

BTW why do you always mumbling about F-35 clone?

Because that is what you keep demanding they make...

wait, wait to they are geniuses of shipbuilding but shitty, open mouth breathing morons copying F-35 design to you?

lol! lol! lol! talking bout size of the brain....

To quote a great Scottish philosopher... "Yeah cannie change the laws of physics Jim..."

but nice you agree then 24-28 fighters and 40ktons is enough to fulfill the role

I would prefer the capacity to take 60-90 fighters, but most of the time just take 40-50 and use the extra capacity for AWACS and helos and of course a range of UAVs.

Russia will soon have the opportunity to build aircraft carriers of new generation with a large displacement than that of "Admiral Kuznetsov", such a possibility is currently being worked out, according to RBC with reference to the President of the United shipbuilding Corporation (USC) Alexey Rakhmanov.

https://z5h64q92x9.net/proxy_u/ru-en.ru/https/vpk.name/news/232515_potencial_est__korablei_net_osk_ozvuchila_perspektivyi_postroiki_avianoscev.html

This is a re-arrangement of the new light-carrier deck, only somewhat wider (85m vs 78) using previous ideas, newly available data and input mainly from Garry. With the new multi-keel design the deck at the stern is so broad that angled deck is not needed anymore IMHO.


This would allow to have an excellent opportunity to increase the reliability of the carrier in case of arresting gear malfunction and operational tempo since two landing decks would be available:


Superstructure would need to be taken to the centreline of the carrier but that would be only good for stability, due to pitch motion it would probably need to be placed close to the CG but if taken backwards it could allow to have a more usable deck, with the center lane full of planes getting ready for TO (actually the whole space in front of the superstructure could be equipped with deflectors for TO as already discussed)

Short ski-jump TO runs with ca. 100 m in red, longer ones with ca. 200 m in blue. Catapult TO positions for tankers and similarly low T/W ratio planes in yellow. The grid is 10 m

LMFS wrote:This is a re-arrangement of the new light-carrier deck, only somewhat wider (85m vs 78) using previous ideas, newly available data and input mainly from Garry. With the new multi-keel design the deck at the stern is so broad that angled deck is not needed anymore IMHO.


This would allow to have an excellent opportunity to increase the reliability of the carrier in case of arresting gear malfunction and operational tempo since two landing decks would be available:


Superstructure would need to be taken to the centreline of the carrier but that would be only good for stability, due to pitch motion it would probably need to be placed close to the CG but if taken backwards it could allow to have a more usable deck, with the center lane full of planes getting ready for TO (actually the whole space in front of the superstructure could be equipped with deflectors for TO as already discussed)

Short ski-jump TO runs with ca. 100 m in red, longer ones with ca. 200 m in blue. Catapult TO positions for tankers and similarly low T/W ratio planes in yellow. The grid is 10 m

Idea of leaving angled flight-deck in favour of parallel take off and landing decks is British invention from late 50s, when they were projecting their CVA-01 class, never laid down. There was a drawing in one of Warship International issues dating from early 70s.

kumbor wrote:Idea of leaving angled flight-deck in favour of parallel take off and landing decks is British invention from late 50s, when they were projecting their CVA-01 class, never laid down. There was a drawing in one of Warship International  issues dating from early 70s.

Thanks for the info! Do you happen to know why this was not implemented? Now maybe automatic landing control can help but from what I know, classical landing on an angled deck is notoriously difficult to master for pilots. And in terms using space, forces the superstructure starboard and reduces the area for parking and TO positions.

I had not seen, previously to QE and the new Russian light carrier, such broad and straight flight decks (width does not reduce at stern). So it seems thinkable to me to get one additional landing deck (with one additional catapult position) and on top of that create additional space for TO out of interference with landings. Such big decks should allow this, and after the Kylov's proposal we know they would not even mean a big displacement increase:


Look how the deck is essentially symmetrical both sides of Y axis.

I think the proposal makes the landing significantly more difficult, reducing the lenght of the available landing trajectories and making narrower the landing space free of obstacles.

eehnie wrote:
I think the proposal makes the landing significantly more difficult, reducing the lenght of the available landing trajectories and making narrower the landing space free of obstacles.

The fundamental issue is, in case the proposal is feasible, whether the added advantages outweigh the problems. And getting one additional landing lane is a huge advantage. Imagine arresting gear fails when you have a wave of aircraft returning to the carrier, they would not be able to land and could (as it happened in Syria) crash in the sea. Tankers are of course another good option there but in times of war they could be busy or you may not have the time to fuel all returning fighters. Also in case the carrier is attacked and receives one single hit on the landing lane, it would be operationally disabled since planes could not land. And of course you have twice the landing speed, one additional catapult position or alternatively lots of place for parking. The space saved would also allow as said to get aircraft in the air way faster since you can queue them at the center of the deck.

To your arguments:

1) Difficulty of the landing
It is precisely the angled landing that is challenging, because it combines motions on three axes at a time (moving left while approaching) unlike a bi-dimensional landing on a straight deck. Such approach is very complex to time properly and can only be done with instrumentation. Straight landing on the contrary would be much easier to master and therefore would reduce the time to form naval pilots and the amount of hours to keep them fit.

2) Length of landing trajectories.
Aircraft take the arresting cables and then are stopped relatively fast, in roughly 100 m. You can look at landing videos to see that the landing deck is not used up completely. But in any case you can calculate the length lost, knowing the angle of decks in carriers is between 5 and 10º, you would lose less than 2% in length by making the landing lane completely straight

3) Landing space free of obstacles.
This would depend of course on how close you place aircraft and other obstacles on the deck. But you can look the parking positions on this and other designs and will see that aircraft land quite close to parked ones. I imagine this changes depending on sea state but cannot say what is acceptable and what is not in what conditions. In any case in the proposal clearance could be made according to situation too.

One concern I would admit is that roll motion would be stronger the more you move the landing lane starboard or backboard compared to the middle line, but I ignore how much this would affect operations under rough sea states, and specially with a new multi-keel design whose stern is probably more stable than a conventional design. Two mitigating strategies would be possible:
> Landing manoeuvre incorporated to the FCS of the plane for automatic roll compensation beyond capabilities of pilot
> Use of a smaller angle for the deck (say 2º) to get more deck space left (or right for the right landing lane) for the landing plane and reduce deck roll motion at the point of contact.

Idea of leaving angled flight-deck in favour of parallel take off and landing decks is British invention from late 50s, when they were projecting their CVA-01 class

Not quite parallel but definitely much straighter than any other post-war carrier designs until the Harrier ships.



Island is quite far inboard to allow planes brought up on the rear lift to pass outboard to the bow catapault without interfering with landing.
~50 Buccaneers, Phantoms & Gannet ASW/AEW would have given it some pretty serious capability.
Shame about the Sea-Slug SAM on the stern though lol  

I've been trying to figure out a layout allowing a smallish CV to do simultaneous takeoff/landing for ages but keep winding up with basically CVA-01 or an extension of Vikramaditya with the long takeoff run crossing the landing run but the setup happening port rear corner clear of the landing run.

I do quite like your ideas here LMFS, though somehow doesn't seem quite right.

hoom wrote:Not quite parallel but definitely much straighter than any other post-war carrier designs until the Harrier ships.

Thanks for the info hoom. In the beginning, angled deck was ca. 5°, then is was increased to 10° with further designs.

I've been trying to figure out a layout allowing a smallish CV to do simultaneous takeoff/landing for ages but keep winding up with basically CVA-01 or an extension of Vikramaditya with the long takeoff run crossing the landing run but the setup happening port rear corner clear of the landing run.

Then, why to make TO and landing runs cross each other? Not needed me thinks. On the one hand due to T/W of modern planes, on the other due to width of modern decks. As to having TO runs as long as possible, AWACS could be done probably to TO in ca. 200 m run with ski jump, but tankers are going to be crucial in the future and they will demand catapults I think.

If you follow the evolution of the CV design you see they started as regular, narrow shaped hulls with a straight deck on the top. Then the jet aircraft made angled deck necessary, with the landing lane starting at the middle of the ship coherently with the shape of the hull. In the time since then, decks grew broader and broader, but kept the same layout. And now with the multi-keel design the flight deck is so wide and straight that I think it is not necessary anymore to have landing and TO runs crossing each other, which only creates interference. Or parking on small gaps here and there, like port of the landing run. Tidier and more effective layout may be possible.

I do quite like your ideas here LMFS, though somehow doesn't seem quite right

Well, thanks! I know it CANNOT be quite right. But I think we may be onto something here, last proposal from Krylov has shed lots of light on how an innovative but realistic multi-keel CV design could look like and shown its advantages.

Wake effects of the superstructure on the landing approach could be an issue when changing the layout of course but I think today that can be measured and managed much better than in the past, and also superstructures are getting smaller every day. I also have a sense that some reasons of keeping current design despite its downsides is due to inertia, given the huge amount of operative experience built. But this is slowly changing and I think it will change further.

LMFS wrote:

hoom wrote:Not quite parallel but definitely much straighter than any other post-war carrier designs until the Harrier ships.

Thanks for the info hoom. In the beginning, angled deck was ca. 5°, then is was increased to 10° with further designs.

I've been trying to figure out a layout allowing a smallish CV to do simultaneous takeoff/landing for ages but keep winding up with basically CVA-01 or an extension of Vikramaditya with the long takeoff run crossing the landing run but the setup happening port rear corner clear of the landing run.

Then, why to make TO and landing runs cross each other? Not needed me thinks. On the one hand due to T/W of modern planes, on the other due to width of modern decks. As to having TO runs as long as possible, AWACS could be done probably to TO in ca. 200 m run with ski jump, but tankers are going to be crucial in the future and they will demand catapults I think.

If you follow the evolution of the CV design you see they started as regular, narrow shaped hulls with a straight deck on the top. Then the jet aircraft made angled deck necessary, with the landing lane starting at the middle of the ship coherently with the shape of the hull. In the time since then, decks grew broader and broader, but kept the same layout. And now with the multi-keel design the flight deck is so wide and straight that I think it is not necessary anymore to have landing and TO runs crossing each other, which only creates interference. Or parking on small gaps here and there, like port of the landing run. Tidier and more effective layout may be possible.

I do quite like your ideas here LMFS, though somehow doesn't seem quite right

Well, thanks! I know it CANNOT be quite right. But I think we may be onto something here, last proposal from Krylov has shed lots of light on how an innovative but realistic multi-keel CV design could look like and shown its advantages.

Wake effects of the superstructure on the landing approach could be an issue when changing the layout of course but I think today that can be measured and managed much better than in the past, and also superstructures are getting smaller every day. I also have a sense that some reasons of keeping current design despite its downsides is due to inertia, given the huge amount of operative experience built. But this is slowly changing and I think it will change further.

hoom wrote:
Not quite parallel but definitely much straighter than any other post-war carrier designs until the Harrier ships.

Thanks for the info hoom. In the beginning, angled deck was ca. 5°, then is was increased to 10° with further designs.

In Eagle and Ark Royal flight deck was angled at 8,5* after refit in 60s. In US CVNs angle is 8*.

Then, why to make TO and landing runs cross each other? Not needed me thinks

Basically because its hard to get a long ramp run to fit ahead of the island on starboard CVA-01 style.
So I figure extend the existing one on Vikramaditya just a bit further so the setup is clear to port/stern of the landing strip.
The crossing does generate some interference but only for a few seconds during a launch.

Something like

It has its issues like proximity to the arrestor gear & lift location but I think fixable on a cleansheet design.


Your current concept actually reminds me a bit of the early CVNX concept for what became Ford.

LMFS wrote:

eehnie wrote:
I think the proposal makes the landing significantly more difficult, reducing the lenght of the available landing trajectories and making narrower the landing space free of obstacles.

The fundamental issue is, in case the proposal is feasible, whether the added advantages outweigh the problems. And getting one additional landing lane is a huge advantage. Imagine arresting gear fails when you have a wave of aircraft returning to the carrier, they would not be able to land and could (as it happened in Syria) crash in the sea. Tankers are of course another good option there but in times of war they could be busy or you may not have the time to fuel all returning fighters. Also in case the carrier is attacked and receives one single hit on the landing lane, it would be operationally disabled since planes could not land. And of course you have twice the landing speed, one additional catapult position or alternatively lots of place for parking. The space saved would also allow as said to get aircraft in the air way faster since you can queue them at the center of the deck.

To your arguments:

1) Difficulty of the landing
It is precisely the angled landing that is challenging, because it combines motions on three axes at a time (moving left while approaching) unlike a bi-dimensional landing on a straight deck. Such approach is very complex to time properly and can only be done with instrumentation. Straight landing on the contrary would be much easier to master and therefore would reduce the time to form naval pilots and the amount of hours to keep them fit.

2) Length of landing trajectories.
Aircraft take the arresting cables and then are stopped relatively fast, in roughly 100 m. You can look at landing videos to see that the landing deck is not used up completely. But in any case you can calculate the length lost, knowing the angle of decks in carriers is between 5 and 10º, you would lose less than 2% in length by making the landing lane completely straight

3) Landing space free of obstacles.
This would depend of course on how close you place aircraft and other obstacles on the deck. But you can look the parking positions on this and other designs and will see that aircraft land quite close to parked ones. I imagine this changes depending on sea state but cannot say what is acceptable and what is not in what conditions. In any case in the proposal clearance could be made according to situation too.

One concern I would admit is that roll motion would be stronger the more you move the landing lane starboard or backboard compared to the middle line, but I ignore how much this would affect operations under rough sea states, and specially with a new multi-keel design whose stern is probably more stable than a conventional design. Two mitigating strategies would be possible:
> Landing manoeuvre incorporated to the FCS of the plane for automatic roll compensation beyond capabilities of pilot
> Use of a smaller angle for the deck (say 2º) to get more deck space left (or right for the right landing lane) for the landing plane and reduce deck roll motion at the point of contact.

In my view one of the main design issues on aircraft carriers is to reduce the risk of accident, the probability of accident in the operation of the aircrafts on board. In the operation of Syria, this was just the main flaw of the service of the Project 11435 A Kutznetsov. In war time, danger situations are forced, the estress in the operations is far bigger, and as consequence the probability of accident increases.

I tend to think that improvements on aircrafts tend to allow to reduce the dependence of the aircrafts from landing and take-off assistance in their operations based on aircraft carriers.

I have not doubt that both take-off and landing assistance systems will continue being designed and used, in order to allow aditional take-off and landing options,  but at same time, I think the new designs of aircraft carriers are trying to reduce the dependence from the use of these systems.

Nothing assures that more than one take-off assistance system and or landing assistance system fails at same time. A proposal with two short landing options that uses necessarily landing assistence, can see both landing options dissabled if both landing assistance systems fail at same time.

I think the new designs are trying to allow take-off and landing of aircrafts without assistence, and it will help to reduce the risk of accident on board and will allow to open new solutions to overrun technical failures of these systems.

In my view the trend in the design is to allow a lower dependence of the aircrafts from landing and take-off assistance systems, and for it is very important to keep the main direction of the aircraft carrier free of obstacles and is very important to go to designs of enough size. Just what Russia is doing.

LMFS wrote:This is a re-arrangement of the new light-carrier deck, only somewhat wider (85m vs 78) using previous ideas, newly available data and input mainly from Garry. With the new multi-keel design the deck at the stern is so broad that angled deck is not needed anymore IMHO.


This would allow to have an excellent opportunity to increase the reliability of the carrier in case of arresting gear malfunction and operational tempo since two landing decks would be available:


Superstructure would need to be taken to the centreline of the carrier but that would be only good for stability, due to pitch motion it would probably need to be placed close to the CG but if taken backwards it could allow to have a more usable deck, with the center lane full of planes getting ready for TO (actually the whole space in front of the superstructure could be equipped with deflectors for TO as already discussed)

Short ski-jump TO runs with ca. 100 m in red, longer ones with ca. 200 m in blue. Catapult TO positions for tankers and similarly low T/W ratio planes in yellow. The grid is 10 m

Why two landing decks ? If they plan ~40 jets plus the rest helicoptets, 1 is enough. In case of malfunction, you can only replace the arresting cables. And they have 4 or 5 of them for one runway.

kumbor wrote:In Eagle and Ark Royal flight deck was angled at 8,5* after refit  in 60s. In US CVNs angle is 8*.

Was rounding the numbers since the difference in angle has little effect in length of the landing run. But have seen anything from 5.5º to 10.5º, including 9º for Nimitz class.

Isos wrote:Why two landing decks ? If they plan ~40 jets plus the rest helicoptets, 1 is enough. In case of malfunction, you can only replace the arresting cables. And they have 4 or 5 of them for one runway.

Higher tempo of operations, more launching positions, higher reliability as explained. You know what happened in Syria with K whit arresting cables right? Apart from that, the need to account for a problem at landing forces planes to save significantly more reserve fuel which cannot be used and is detrimental to their performance without providing useful range and besides unnecessarily loads the airframes during landing.

Apart from that you get a better usage of the deck because you don't have a run crossing transversally, leaving irregular and small patches of deck left and right that are difficult to use. Look below how chaotic a modern deck is:


Operational possibilities for the proposal:

> Normal operation: TO from the ski jump, with planes being prepared further backwards. Aircraft parking on one landing run. The other landing run ready for receiving aircraft
> High tempo TO: Planes ready for TO at ski jump and two catapults
> High tempo landing: two landing runs cleared and receiving planes in parallel
> Alternatively, landing on one lane while the ski jump sends fighters in the air and the catapult on the other landing run allows to operate AWACS or tankers without interference.

This allows to create higher intensity and hence compensate for smaller number of aircraft on board and less catapults than a US CVN

So this is in the end a lot of improvements for safety, reliability and performance. I don't say current formula is not valid, only that it can be improved!  

eehnie wrote:In my view one of the main design issues on aircraft carriers is to reduce the risk of accident, the probability of accident in the operation of the aircrafts on board. In the operation of Syria, this was just the main flaw of the service of the Project 11435 A Kutznetsov. In war time, danger situations are forced, the estress in the operations is far bigger, and as consequence the probability of accident increases.

Agree. Don't see why this system would be more dangerous, as explained the straight deck is notably easier to land into. And the redundant landing runs address the problem you mention above.

I tend to think that improvements on aircrafts tend to allow to reduce the dependence of the aircrafts from landing and take-off assistance in their operations based on aircraft carriers.
I think the new designs are trying to allow take-off and landing of aircrafts without assistence, and it will help to reduce the risk of accident on board and will allow to open new solutions to overrun technical failures of these systems.
I have not doubt that both take-off and landing assistance systems will continue being designed and used, in order to allow aditional take-off and landing options,  but at same time, I think the new designs of aircraft carriers are trying to reduce the dependence from the use of these systems.
I think the new designs are trying to allow take-off and landing of aircrafts without assistence, and it will help to reduce the risk of accident on board and will allow to open new solutions to overrun technical failures of these systems.

It depends:
If you make a LHD then you use STOVL precisely to make TO and landing relatively independent on assistance, because your ship is not equipped. But this drags the plane instead of the carrier, which is the piece of equipment specifically intended for that role of supporting naval aviation. Today this means the LHDs have a supporting role with focus on amphibious operations while CVNs carry the big stick and have upgraded steam catapults to EMALS and also modernized the arresting gear, the assistance to operations is not going anywhere but in fact getting more sophisticated and capable. This is state of things today I would say.

Nothing assures that more than one take-off assistance system and or landing assistance system fails at same time. A proposal with two short landing options that uses necessarily landing assistence, can see both landing options dissabled if both landing assistance systems fail at same time.

Well, that is actually the opposite of how you think in terms if risk mitigation. If your arresting gear "A" has a 1% probability of being disabled and it operates equally and independently of system "B", then the probability of both being out of operation at the same time is 0.01%, which is two orders of magnitude less in this particular case. Obviously this makes quite a lot in terms of ensuring your planes will be able to land instead of crashing in the sea.

BTW, don't know where you are taking from the notion that the landing options are shorter. This is the shape and dimensions of the new light carrier proposed by Krylov, only a little wider, which should be perfectly doable with little more displacement, multi-keel design and maybe nuclear propulsion. Landing runs are roughly 200m as in most other carriers, have not measured them exactly in the Krylov model (no good view available) but they could be as long as in the original without a problem...

In my view the trend in the design is to allow a lower dependence of the aircrafts from landing and take-off assistance systems, and for it is very important to keep the main direction of the aircraft carrier free of obstacles and is very important to go to designs of enough size. Just what Russia is doing.

IIRC you suggested CTOL planes operating at the carriers. This (may) be partially possible for TO with ski jump and powerful engines, but for landing it wont work, there is no CTOL jet plane that can be stopped in less than 300 m without arresting gear. Maybe some engine reverser together with parachute could help? I don't know it honestly...
So, while I agree form a general point of view that it would be good to reduce assistance, there is a limit in current technical conditions. The best option for me is the Russian one, with ski jump for the fighters and catapults for other planes unlike the USN carriers without ski jump.

hoom wrote:Basically because its hard to get a long ramp run to fit ahead of the island on starboard CVA-01 style.
So I figure extend the existing one on Vikramaditya just a bit further so the setup is clear to port/stern of the landing strip.
The crossing does generate some interference but only for a few seconds during a launch.

But why do you think it is necessary to have such long TO runs? Modern T/W ratio makes no problem for a fighter to TO from 100 runs. In case of tankers I guess the relevance of increasing payload can make more interesting to put catapults in he end.
Taking a plane to the TO position is another moment where you interfere with landing.

Your current concept actually reminds me a bit of the early CVNX concept for what became Ford.

Wow that design changed a bit in the path to actual implementation    

Higher tempo of operations, more launching positions, higher reliability as explained. You know what happened in Syria with K whit arresting cables right? Apart from that, the need to account for a problem at landing forces planes to save significantly more reserve fuel which cannot be used and is detrimental to their performance without providing useful range and besides unnecessarily loads the airframes during landing.

K isn't a reliable exemple. It was the fault of old equipment. Which is also weired since it has many wires, so all of them became unusable when the mig 29k landed ?

Apart from that you get a better usage of the deck because you don't have a run crossing transversally, leaving irregular and small patches of deck left and right that are difficult to use. Look below how chaotic a modern deck is:

You can make it with one runway and not be transversally. And use the other part for parking and helicopters/VSTOL take off.

LMFS wrote:

Nothing assures that more than one take-off assistance system and or landing assistance system fails at same time. A proposal with two short landing options that uses necessarily landing assistence, can see both landing options dissabled if both landing assistance systems fail at same time.

Well, that is actually the opposite of how you think in terms if risk mitigation. If your arresting gear "A" has a 1% probability of being disabled and it operates equally and independently of system "B", then the probability of both being out of operation at the same time is 0.01%, which is two orders of magnitude less in this particular case. Obviously this makes quite a lot in terms of ensuring your planes will be able to land instead of crashing in the sea.

BTW, don't know where you are taking from the notion that the landing options are shorter. This is the shape and dimensions of the new light carrier proposed by Krylov, only a little wider, which should be perfectly doable with little more displacement, multi-keel design and maybe nuclear propulsion. Landing runs are roughly 200m as in most other carriers, have not measured them exactly in the Krylov model (no good view available) but they could be as long as in the original without a problem...

I said nothing about probability. Your "opposite of how you think" mention is fairly audatious and baseless. Why do you expect the people reading do not know that you are using the definition of independent events and the definition of conditional probability to do the calculus of the probability of the intersection? In fact your calculus is quite basic, of secondery education level in my native country (and likely in most), previous to a engineering degree in the university.

About the second part, this is also very basical knowledge, not something where an engineer can even doubt. For a given dimmenssion of the deck, with the poop perpendicular to the main axis of the aircraft carrier like seems to be in your figure, a landing trajectory paralel to the main axis of the aircraft carrier will be always shorter than a landing trajectory with some angle. As example, if the lenght of the landing trajectories of your model (paralel to the main axis of the aircraft carrier) are of 160m, a landing trajectory with an angle of 10º from the main axis of the aircraft carrier will have a lenght of 160m/cos(π/18)=162.47m. Even minimal angles add some lenght to the landing trajectory.

LMFS wrote:

In my view the trend in the design is to allow a lower dependence of the aircrafts from landing and take-off assistance systems, and for it is very important to keep the main direction of the aircraft carrier free of obstacles and is very important to go to designs of enough size. Just what Russia is doing.

IIRC you suggested CTOL planes operating at the carriers. This (may) be partially possible for TO with ski jump and powerful engines, but for landing it wont work, there is no CTOL jet plane that can be stopped in less than 300 m without arresting gear. Maybe some engine reverser together with parachute could help? I don't know it honestly...
So, while I agree form a general point of view that it would be good to reduce assistance, there is a limit in current technical conditions. The best option for me is the Russian one, with ski jump for the fighters and catapults for other planes unlike the USN carriers without ski jump.

The time will say.

In order to complete my point I can say that:

- I do not support STOVL or VTOL technologies applied to manned fighters, because they affect to the performance of the figther. I instead strongly support the use of VTOL technologies for unmanned platforms, specially shipborne.

- I consider that curve landing trajectories add risks and danger. In my view the main axis of the aircraft carrier need to be respected without obstables in all its lenght.

eehnie wrote:I said nothing about probability. Your "opposite of how you think" mention is fairly audatious and baseless. Why do you expect the people reading do not know that you are using the definition of independent events and the definition of conditional probability to do the calculus of the probability of the intersection? In fact your calculus is quite basic, of secondery education level in my native country (and likely in most), previous to a engineering degree in the university.

Bravo. That is where you (after having done the same with n forum members before) get personal and start saying BS before I cut this for good. The underlying error, improper not of an engineer but of any person with common sense, is you essentially denying the principle of redundancy by saying it does not help having two systems since they could both fail at the same time... I engaged in basic reasoning not because I am an idiot but out of good will and frankly patience, because you were not understanding such a trivial issue. But you behaving like a dick changes things a bit so there you have the cold truth served, I don't care if you are hypersensitive and don't like being shown or corrected, if you got hurt by my basic calculations man up.

About the second part, this is also very basical knowledge, not something where an engineer can even doubt. For a given dimmenssion of the deck, with the poop perpendicular to the main axis of the aircraft carrier like seems to be in your figure, a landing trajectory paralel to the main axis of the aircraft carrier will be always shorter than a landing trajectory with some angle. As example, if the lenght of the landing trajectories of your model (paralel to the main axis of the aircraft carrier) are of 160m, a landing trajectory with an angle of 10º from the main axis of the aircraft carrier will have a lenght of 160m/cos(π/18)=162.47m. Even minimal angles add some lenght to the landing trajectory.

Look, that trivial calculation was the reason I told you there was less than a 2% reduction of the length of the lane by making it straight in the first place. So spare us your lessons on basic trigonometry and especially personal attacks for 2.5 meters difference over 160, it is so ridiculous I am not even going to lose time over it. You show no clue about numbers, about their significance and what is worse, about basic civility. Have fun

But why do you think it is necessary to have such long TO runs? Modern T/W ratio makes no problem for a fighter to TO from 100 runs. In case of tankers I guess the relevance of increasing payload can make more interesting to put catapults in he end.
Taking a plane to the TO position is another moment where you interfere with landing.

Longer in the V example to get the launch position clear of the landing strip, only needs a few more meters.
On a cleansheet design you might have a (relatively) shorter bow with the normal length run but I don't think there is really such thing as 'too long'.

Cleansheet design would have a port rear lift behind the launch spot (& associated hangar location/setup) so planes can be brought up without crossing the landing strip.

LMFS, just to remember:

LMFS wrote:

Nothing assures that more than one take-off assistance system and or landing assistance system fails at same time. A proposal with two short landing options that uses necessarily landing assistence, can see both landing options dissabled if both landing assistance systems fail at same time.

Well, that is actually the opposite of how you think in terms if risk mitigation. If your arresting gear "A" has a 1% probability of being disabled and it operates equally and independently of system "B", then the probability of both being out of operation at the same time is 0.01%, which is two orders of magnitude less in this particular case. Obviously this makes quite a lot in terms of ensuring your planes will be able to land instead of crashing in the sea.

The first and alone personal reference was from you. To assume that I do not know the definitions of independent event and of conditional probability, and that I think the opposite, was quite audatious and unfriendly.

Unlike you, I did not personal attacks.

And no, in my previous words there is not a denial of the principle of redundance.

If you want to traslate properly my words to probabilities, I was saying that the probability of both landing trajectories being disabled at same time is not 0. The landing assistence systems of both can fail at same time, and sooner or later this problem will appear under a proposal that forces dependence of landing assistance. Instead, in a design with enough size, that allows landing and take-off without assistance, keeping free of obstacles the main axis of the aircraft carrier, there is not this problem.

LMFS wrote:BTW, don't know where you are taking from the notion that the landing options are shorter.

Basically, you asked.

With the new multi-keel design the deck at the stern is so broad that angled deck is not needed anymore IMHO.

It still uses an angled deck, but with less angle so the angled deck is much longer.

The purpose of the angled deck is to allow aircraft to land continuously even while aircraft are set up on the launch positions and are prepared for take off.

If you look at the model on your post (number 560) you can clearly see that the gray and blue plane right up the front ready in the front two takeoff positions (yellow lines showing their take off paths).

Just behind them on the deck is a gray aircraft with wings folded but it is surrounded by a yellow oval which indicates an aircraft lift, of which there are three including one right at the rear of the carrier deck.

Behind the front aircraft lift and to the left is the third takeoff position... you can identify them because they have gray rectangles on the deck where there is a blast deflector which can be raised to allow the aircraft in that position to run at full AB without damaging any aircraft or personnel behind them.

Note the left aircraft in the front takeoff position you can see the blast reflectors are up and you can see the red painted underside of that deflector.



You can also see a blue aircraft in the process of landing on the angled deck and various aircraft parked around the place, including one on each of the aircraft lifts.

You can clearly see that the rear launch position is partially on the landing strip but narrowly avoids the deck lift slightly in front of it.

The funny small rectangular shapes that look like a large rectangle with a small rectangle added on between the aircraft lifts and the main structure in line and behind the right front aircraft take off position are probably ammunition lifts.

This would allow to have an excellent opportunity to increase the reliability of the carrier in case of arresting gear malfunction and operational tempo since two landing decks would be available:

Arrester gear malfunction is unusual and not worth redesigning a whole carrier for.

Superstructure would need to be taken to the centreline of the carrier but that would be only good for stability, due to pitch motion it would probably need to be placed close to the CG but if taken backwards it could allow to have a more usable deck, with the center lane full of planes getting ready for TO (actually the whole space in front of the superstructure could be equipped with deflectors for TO as already discussed)

You never see a land based aircraft tower in the middle of landing air strips and you wont see a carrier tower in the same place.

The only modern change for towers is the split of the ships tower and the aircraft control tower...

OK then why only US is building large CVNs? because money dont matter!

Their income depends on their empire, so they need the tools of empire to keep the little ones in line... when they lose the herd they lose the farm.

No, thy dotn you do.

You are the one wanting a supersonic 5th gen STOVL fighter...

you might prefer eve 12 of them. Ru Navy too. But in reality realm money is in tight supply. Navy already is cured form 90ktson Storm, now they are mumbling about 70ktons. Likely will be happy with 40ktons too.

The Ru Navy never expressed any interest in a 90 K ton Storm class carrier.... that was an offering from a design bureau that has never made a CVN.

The Ru Navy has said the Kuznetsov is slightly too small and they want something a little bigger in the 70K tons range Max weight.

Thanks for the info! Do you happen to know why this was not implemented? Now maybe automatic landing control can help but from what I know, classical landing on an angled deck is notoriously difficult to master for pilots. And in terms using space, forces the superstructure starboard and reduces the area for parking and TO positions.

Landing on a carrier in the middle of an ocean with the deck heaving up and down has and is and will always be difficult... they used to land straight and it wasn't any easier and if you screwed it up you risked running into other aircraft on the deck and making a real mess of things.

An angled deck design means you have your little corner of the deck to yourself so if you miss the cable you can fly through and come around and have another go.

I don't understand why you find fault with such a clever design.

Look how the deck is essentially symmetrical both sides of Y axis.

The extra space on deck is better used for parking of aircraft than adding the enormous complication of two landing runs... they already have three take off runs...

Imagine arresting gear fails when you have a wave of aircraft returning to the carrier, they would not be able to land and could (as it happened in Syria) crash in the sea.

Yeah... imagining the arresting gear fails is like imagining the carrier hits a mine and sinks... so make it a hovercraft...

1) Difficulty of the landing
It is precisely the angled landing that is challenging, because it combines motions on three axes at a time (moving left while approaching) unlike a bi-dimensional landing on a straight deck. Such approach is very complex to time properly and can only be done with instrumentation. Straight landing on the contrary would be much easier to master and therefore would reduce the time to form naval pilots and the amount of hours to keep them fit.

What are you talking about?

You line up with the runway for landing... you don't land in a circle... you land in a straight line.... whether that is parallel to the deck of the ship or angled to the deck of the ship... the tried and trusted mirror system makes landing fairly straight forward... and the angled deck is no harder than a straight deck landing.

2) Length of landing trajectories.
Aircraft take the arresting cables and then are stopped relatively fast, in roughly 100 m. You can look at landing videos to see that the landing deck is not used up completely. But in any case you can calculate the length lost, knowing the angle of decks in carriers is between 5 and 10º, you would lose less than 2% in length by making the landing lane completely straight

The length used for a cable landing depends on whether the aircraft caught the first, second, third, or fourth cable... if you get the fourth cable the aircraft uses almost all of the angled deck length to stop. Having extra length in this case means nothing at all, unless you want to use longer cables.

3) Landing space free of obstacles.
This would depend of course on how close you place aircraft and other obstacles on the deck. But you can look the parking positions on this and other designs and will see that aircraft land quite close to parked ones. I imagine this changes depending on sea state but cannot say what is acceptable and what is not in what conditions. In any case in the proposal clearance could be made according to situation too.

The purpose of an angled deck is to allow for missing the cables... or indeed crashing in a big fireball, but not having parked aircraft or people traffic in the way...

Push the burning wreck off the deck and hose it down and next aircraft...

Not quite parallel but definitely much straighter than any other post-war carrier designs until the Harrier ships.

One landing strip with a slight angle, and a bow to allow rolling takeoffs... that is just normal.

AWACS could be done probably to TO in ca. 200 m run with ski jump, but tankers are going to be crucial in the future and they will demand catapults I think.

AWACS and tanker aircraft are practically transports and transports wont like ski jumps... too much weight.... too much g force at too much weight will just break them.

If you are going to have cats for a tanker when why not use them for AWACS too?

Tidier and more effective layout may be possible.

They used to use straight decks because the old propeller driven aircraft could get airborne in that distance... though sometimes only with a good head of steam into the wind.

Jet aircraft simply didn't have any chance of getting airborne or more importantly landing in such a small area so cable arresting gear and steam cats were developed.

With cable arresting gear you only needed a fraction of the length of the deck to land or follow through and come around again, so an angled deck was used because it isolated the area of the deck used up for landing and freed up the rest of the space for parking and preparing aircraft for take off or weapon loading.

The only exception is VTOL aircraft like Harrier types and helicopters... where rolling landings and rolling takeoffs allow operating at heavier weights easier, which improves aircraft performance.

It has its issues like proximity to the arrestor gear & lift location but I think fixable on a cleansheet design.

With cats the longer takeoff runs become redundant... it would be better to use the extra space for parking aircraft...

In my view one of the main design issues on aircraft carriers is to reduce the risk of accident, the probability of accident in the operation of the aircrafts on board. In the operation of Syria, this was just the main flaw of the service of the Project 11435 A Kutznetsov. In war time, danger situations are forced, the estress in the operations is far bigger, and as consequence the probability of accident increases.

The situation in Syria was unusual and was a result of them never operating at such a tempo before. The problem will have been dealt with by now so trying to redesign the whole carrier to reduce the problems is a waste of time.

Changing the landing run to the full length of the deck is not enough to allow landing without cable arrester gear, so why bother?

Why two landing decks ? If they plan ~40 jets plus the rest helicoptets, 1 is enough. In case of malfunction, you can only replace the arresting cables. And they have 4 or 5 of them for one runway.

Cables break in normal operation... but of course not all the time. If they break all the time then that is a problem with the arrester gear itself... without arrester gear all cables will break first time every time... arrester gear is like the gears in a car that allow it to operate at different speeds... without it you would either have serious problems starting off or going up hill because of the high fixed gear ratio that allows you go travel on high ways efficiently, or you can start off easy, but can't drive much faster than 50km/h without the engine roaring at 12 thousand revs.

K isn't a reliable exemple. It was the fault of old equipment. Which is also weired since it has many wires, so all of them became unusable when the mig 29k landed ?

If the arrester gear is not working then all of the cables will snap when caught because there is no gearing to give them give... they are not elastic bands.

GarryB wrote:Changing the landing run to the full length of the deck is not enough to allow landing without cable arrester gear, so why bother?

This begins to be in doubt.

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The domestic aviation industry is undergoing big changes. In a year and a half, Russia will supply the market with the brand-new MC-21 medium-haul airliner — this is the main hope of our civil aviation. Meanwhile, the Russian Air Force has high hopes for the main military breakthrough — the Su-57 fifth-generation jet fighter. When will it go into service? What other kinds of aircraft should we expect?

Yuri Slyusar, the head of the United Aircraft Corporation, spoke about this with our reporter Nailya Askerzade.

The Su-57 jet fighter is in the sky over Zhukovsky. Fast, maneuverable, and completely invisible to foreign radar systems. A 300-meter-long runway is enough for it in order to take off.

Nailya Askerzade, reporter: "Of course, many people dream of at least approaching the top-secret Su-57 fifth-generation jet fighter. We have a unique opportunity to look at it in detail. This "king of dogfighting" is so unique that we aren't allowed to film everything. The state-of-the-art target acquisition system allows target tracking at a considerable distance, the engine features greater thrust and fuel efficiency, and the smart cockpit advises the pilot how to operate.

Taras Artsebarsky, test pilot: "In fact, having flown this plane, when I happen to fly the previous generation jet, I can't help noticing the imperfections, the things that are missing compared to the new one. The new jet features a powerful AI support system for the pilot; it performs a lot automatically and, overall, it allows the pilot to concentrate on the main combat tasks without any distractions".

Taras Artsebarsky is a first-class test pilot. He is the son of cosmonaut Anatoly Artsebarsky, so he's been close to the sky since his childhood. He has already mastered more than 20 types of aircraft, so he has a big sample size for comparison.

- Do you remember your first flight on this fighter?

- Of course, I do. Pilots always remember such things; any sortie on a new type of aircraft is unforgettable and even more so if it is such a fighter jet.

- What nickname did you and your colleagues give this aircraft?

- We nicknamed it affectionately, kindly, by his index name — "Poltinnik" (fifty). And we're still calling it that because we're used to now.

The West got intrigued by these aircraft after two such jets were transported to Syria in February.

- When will the Ministry of Defense take charge of these planes?

Yuri Slyusar, President of the United Aircraft Corporation: By the end of this summer. I think, at Patriot Park, we'll sign a contract with the Defense Ministry regarding the delivery of the first production batch. This is such a significant event for us. In total, we have planned to purchase around 12 jets so, next year, they will be supplied directly to the unit.

hoom wrote:Longer in the V example to get the launch position clear of the landing strip, only needs a few more meters.
On a cleansheet design you might have a (relatively) shorter bow with the normal length run but I don't think there is really such thing as 'too long'.

Cleansheet design would have a port rear lift behind the launch spot (& associated hangar location/setup) so planes can be brought up without crossing the landing strip.

Ok understood. What I mean is that the short runs should be ok for new carriers with new fighters in 100% of the cases and are already ok for 90% of missions. The longer runs through the ski jump, I am not sure they would add that much. Maybe with UCAVs could be of help, with tankers I guess not and with AWACS I have my doubts.

I would always prefer strips that do not cross each other, that is why I propose to make them straight. But if this is not possible and the use is restricted to some planes then your idea could work. What I don't see quite ok is if you plan to launch many fighters from that position, since you cannot park and prepare many planes in the same area (or maybe I am wrong, how many are you calculating to be parked in that area?), I think this would make the TO tempo slow (if only one plane can be lifted and then armed and prepared for launch each time) or would add interference to the landings (if the planes are armed somewhere else and then cross the landing strip). The space left port of the landing strip is narrow and angled, so it cannot be used very well. If you make a big space for parking and preparing the planes port of the landing strip, wouldn't it be better to move the landing strip altogether and avoid crossings?

eehnie wrote:The first and alone personal reference was from you. To assume that I do not know the definitions of independent event and of conditional probability, and that I think the opposite, was quite audatious and unfriendly.

Was not being unfriendly, at all. The construction you point out as hostile could be also written "this is not how things are done in risk mitigation", has nothing to do with "you" personally and is quite frequent in English. I was not thinking for a second you would ignore basic probability or trying to give a master class to anyone for God's sake, but if you discuss obvious things I will have to go to obvious reasoning.

Unlike you, I did not personal attacks.

Yes you did, FYI. Rather rude ones.

And no, in my previous words there is not a denial of the principle of redundance.

If you want to traslate properly my words to probabilities, I was saying that the probability of both landing trajectories being disabled at same time is not 0. The landing assistence systems of both can fail at same time, and sooner or later this problem will appear under a proposal that forces dependence of landing assistance. Instead, in a design with enough size, that allows landing and take-off without assistance, keeping free of obstacles the main axis of the aircraft carrier, there is not this problem.

Yes, any system destined to stop the plane can fail, be it on board of the carrier or on board of the plane. And you cannot land in 300 m without assistance, sorry. Take a look at actual data.

GarryB wrote:It still uses an angled deck, but with less angle so the angled deck is much longer.

Maybe I am missing something:
> The angle at the new Krylov proposal is quite conventional (between 5 and 10º)
> The smaller the angle, the shorter the strip, even if by an insignificant amount

The purpose of the angled deck is to allow aircraft to land continuously even while aircraft are set up on the launch positions and are prepared for take off.

Yes by now even I know this. The issue is, with decks being so wide, landing strip can be parallel to the carrier's axis instead of angled, without it losing its function, namely allow simultaneous landings and TOs

If you look at the model on your post (number 560) you can clearly see...

Ahaaa... yes I can see all that Garry... what do you  exactly mean?  

Arrester gear malfunction is unusual and not worth redesigning a whole carrier for.

The issue is infrequent but its impact is very serious, because it essentially leaves the planes in the air with nowhere else to go. And it is of course not the only risk factor during landing
> New arresting gear is also relying heavily on power electronics, due to the need of easing the loads of the landing for different planes at different weights. So it is getting complicated too.
> Naval fighters need to carry big amounts of extra fuel and keep it as reserve (30% according to Yakovlev article I posted some days ago). This is a huge amount, needed only as prevention of a eventuality that prevents from landing as scheduled, as a crash, damaged arrestors, malfunction of plane after landing, delays etc. Redundancy would ease enormously these issues.

You never see a land based aircraft tower in the middle of landing air strips and you wont see a carrier tower in the same place.

Maybe, but why?

Landing on a carrier in the middle of an ocean with the deck heaving up and down has and is and will always be difficult...

Well, I don't exactly know if modern planes cannot take care of this automatically but I guess pilots need to be capable of doing it regardless.

they used to land straight and it wasn't any easier and if you screwed it up you risked running into other aircraft on the deck and making a real mess of things

An angled deck design means you have your little corner of the deck to yourself so if you miss the cable you can fly through and come around and have another go.

Just in case, I am not proposing to land straight in collision course with the planes in the TO queue... simply eliminating the bad consequences of the angled layout. Angled decks appeared together with jet fighters, that could not land as the propeller models. It is clear to me their function is needed!

I don't understand why you find fault with such a clever design.

No, no fault. I just think they evolved the way they did out of need, due to the narrow stern of old carriers, and remained that way even when the carriers themselves changed notably. Nowadays this restriction of a narrow stern is gone and I think the space can be used better, allowing more landing strips and increased independence between the different areas and operations on the deck.

The extra space on deck is better used for parking of aircraft than adding the enormous complication of two landing runs... they already have three take off runs...

I am pretty sure this is a big advantage as explained above and in previous posts, but well, I am no naval expert!

Yeah... imagining the arresting gear fails is like imagining the carrier hits a mine and sinks... so make it a hovercraft...

One single landing strip is a bottleneck... if you can remove it you are better without it.

What are you talking about?

You line up with the runway for landing... you don't land in a circle... you land in a straight line.... whether that is parallel to the deck of the ship or angled to the deck of the ship... the tried and trusted mirror system makes landing fairly straight forward... and the angled deck is no harder than a straight deck landing.

The ship moves forward while you move at an angle with it, this is not the simplest motion to coordinate. As you say, an instrument is needed so the pilot can do it. Further, there is a misalignment between the axis of the plane and that of the deck during the touchdown, due to their relative movement. Do not know how hard this is on the landing gear and structure but doesn't seem ideal to me. References I have read indicate the angled landing is indeed more complicated and pilots need special training for it.

The length used for a cable landing depends on whether the aircraft caught the first, second, third, or fourth cable... if you get the fourth cable the aircraft uses almost all of the angled deck length to stop. Having extra length in this case means nothing at all, unless you want to use longer cables.

I know, also don't see this as a critical issue, was just answering eehnie. But in any case, the bigger the strip, the bigger the allowance for failures and maybe as you point out you can manage less aggressive landings if you set up your arresting gear accordingly. New intelligent gear should be capable of doing this, saving airframe hours.

The purpose of an angled deck is to allow for missing the cables... or indeed crashing in a big fireball, but not having parked aircraft or people traffic in the way...

Push the burning wreck off the deck and hose it down and next aircraft...

   You say it as if removing a crashed fighter was like sweeping the floor with a broom! In reality it means lengthy operations and the planes waiting on the air need to have significant amount of extra fuel in prevision of such things.

AWACS and tanker aircraft are practically transports and transports wont like ski jumps... too much weight.... too much g force at too much weight will just break them.

If you are going to have cats for a tanker when why not use them for AWACS too?

Not sure about the first part but you may have a point.
Regarding the second, there are some options now for AWACS or AEW that may solve this function with a different type of platform, some of them even V/STO capable. That is why I focus on tankers, which are heavily dependant in payload and hence will need catapults to be competitive. But of course, if you have them you can launch your AWACS too!