I don't need to know. It's called a hypothetical debate.

Interesting.

 

 Planes already feature strong wheel brakes. But wheels are so very small, weight distribution, stability, etc can only do so much. Imagine trying to stop a 40 ton semi trailer doing 200 kmph with brakes and tyres off a Volkswagon golf. They are most effective in the last stage of slowing down under 80kmph.

 

 Some/many of these have been tried before. Buccaneer had airbrakes in its tail section and blown wings to increase lift at low speeds.  The airbrakes could be enlarged. Swing wing aircraft have been tried many times before to a great deal of success (if abit expensive).

 

 I think such a ship could achive 25-30 kts in favourable coniditions given the right motorvation.

 

 Would be a huge carrier tho. Displacement would be 2-300,000+ tons? Airwing of what? 100+ aircraft. You could proberly land/operate Spartans and maybe Hercs on its too.

 

 

It's hypothetical of cause, but judging from the largest containerships (Emma Maersk) just under 0,5kW per ton displacement, will give 25 knots sustained. Going to 300.000+ tons all things else being equal, should give more speed for the same power-to-displacement ratio, but I don't think 30 knots is realistic.......27 knots, maybe?
 

The very efficient hull shape of containerships has a larger block coefficient than the typical aircraft carrier, so displacement is more likely to be 300.000-350.000 tons with 150-175MW propulsive power (US CVNs have ~206MW). The hull would probably be less maneuvable, but that can be countered by installing azimuthing propulsion pods, which happens to be the most efficient method of pushing a hull throught water anyway (Google CRP Azipod.

 

The idea is not to have larger airwings. A US CVN with full airwing already represent a formiddable force as well as an almost unimaginable finansial commitment. Concentrating more personnel and more dollar value on one single vessel is in my oppinion not the way forward. The motivation would primarily be:

 

- building a simpler and therefore cheaper ship with at least similar capability to a CVN. Steel is cheap, especially if you can use a lower grade steel than the very expensive weightsaving quality used on today's CVNs.

- provide a warm, dry, lit-up hangar for the entire airwing, enabling first class round-the-clock maintenance. Protecting the ever more expensive aircraft from the wet, windy, salty environment on the flight deck as much of the time as possible is a priority too.

- provide for larger AvGas and weapons stocks, thereby reducing the need for frequent replenishment.

- more battle damage absorbtion capacity.

 

Finally, yes the C-27J Spartan could easily land and take-off from such a deck. Consider the possible development of a navalized Spartan, with folding tail and outer wings. It would even fit in the hangar provided the elevator was dimensioned accordingly. Spartan variants could eventually provide AEW, COD, maritime patrol, A2A refuelling, insertion and extraction of specal forces....what else?

A carrier like this would be almost completely ineffective.  Sortie rates would be dismal because of slow plane handling.  It couldn't operate in any but the most benign sea states due to the length of takeoff and landing rolls.  It maximizes the single most dangerous portion of flight -- takeoff and landing runs -- and makes them even more dangerous due to a narrow, pitching and rolling deck.  What do you do if you blow a tire on landing or takeoff, or your brakes fail on landing?  Yup: you swerve off the deck or into a row of parked aircraft.

CATOBAR carriers work really well because they get the plane into and out of the air as fast as possible, and minimize the impact of things like ice and water on the deck and motion of the boat.  STOVL carriers do this too, obviously in a completely different way.

Sortie rates largely depends on the size of the airwing and the number of people to service that airwing. Theoretically a US CVN can make 2000+ catshots and almost as many traps in a 24 hours period, but in the real world the figure is unlikely to exceed 200 due to lack of airframes and personnel. Your point about slow plane handling is therefore - besides beeing wrong - also a moot point. Plane handling will be just as fast, if not faster, than on a CATOBAR. With a lot of deckspace, no catapult to hook up and no arresting wires to get entangled in, there would be nothing slowing the stream of aircraft as they land and roll to a side one after the other. Take off would be similar, a queue would form near the stern, to one or both sides; aircraft would wait for a clear runway, roll in and acellerate away immediately. Remember, we are discussing an 8 acres flightdeck as opposed to the 4½ acres of a US CVN. Plus, you'd have a largely clear flight deck with lots of space for movement of planes, as the inactive portion of the airwing is expected to be in the enormous hangar.

The pitching and rolling deck objection you raise is another non issue; the US Navy conducted conventional landings with a Hercules ( 21 landings and take-offs) on Forrestal in 1963, deeming it safe and unproblematic . The sea was described as mildly rough with the bow piching 30ft. If  you can do it with such a huge aircraft on Forrstal, I fail to understand why it couldn't be done equally safe with much smaller planes on a much larger ship. The larger the ship, the less pitch and roll.....all things else being equal, n'est pas? Besides, active stabilization is pretty much standard these days on many ships. 

 

As for malfunctions and mishaps; yes, they will happen......as they do and repeatedly have done on CATOBAR carriers the past 50+ years. Naval aviation is a dangerous business, which is why you will have to work out procedures minimizing mishaps, accidents and fatalities. This has been done for CATOBAR carriers over a period of more than 50 years; but that cannot be used as basis for an argument against other ways of doing things. Besides, whether CATOBAR carriers work really well is a matter of oppinion. Given the size of carriers up till today the only viable alternative that have been truly tested is the STOVL carrier, which is superior for smaller ships. Given the time, operational experience and money to perfect a very large straight-deck STOL carrier there is no reason to believe it could not outperform the CATOBAR concept (for less money and manpower). 

The problem with this whole notion is that while you do have a lot of deck space, you're giving up a large proportion of it because of your landing and takeoff distance requirements.  If we assume your 480m ship has the same proportions as the Emma Maersk (397m l, 56m beam), then its width is still only 67m, less than the flight deck width of a Nimitz class carrier (76m).  The landing area will have to be about 40 meters wide.  That doesn't leave you a lot of room to park and maneuver aircraft around when landings require the entire length of the flight deck.

Plane handling will be just as fast, if not faster, than on a CATOBAR. With a lot of deckspace, no catapult to hook up and no arresting wires to get entangled in, there would be nothing slowing the stream of aircraft as they land and roll to a side one after the other.

And then they just sit there?   Where are they rearmed and serviced, and how do they get to this place? What happens to the other aircraft in the pattern while these aircraft taxi around?

Take off would be similar, a queue would form near the stern, to one or both sides; aircraft would wait for a clear runway, roll in and acellerate away immediately. Remember, we are discussing an 8 acres flightdeck as opposed to the 4½ acres of a US CVN. Plus, you'd have a largely clear flight deck with lots of space for movement of planes, as the inactive portion of the airwing is expected to be in the enormous hangar.

See the dimensions I stated above.  You're going to have a hard time marshalling all these aircraft around to the takeoff spots in 27m of deck width.  Again, where is this enormous hangar, and where is all the room required to get aircraft from it to "the runway"?  Sure, you've got more area than a Nimitz, but you're also using a lot more of it to conduct either landings or takeoffs.

The pitching and rolling deck objection you raise is another non issue; the US Navy conducted conventional landings with a Hercules ( 21 landings and take-offs) on Forrestal in 1963, deeming it safe and unproblematic . The sea was described as mildly rough with the bow piching 30ft. If  you can do it with such a huge aircraft on Forrstal, I fail to understand why it couldn't be done equally safe with much smaller planes on a much larger ship.

A test pilot flying a C-130 into a 40-knot wind to land on a completely empty carrier deck doesn't really have a lot to do with flying a tactical jet to and from a crowded ship.  IIRC he was able to come to a stop in something under 300 feet, which is going to be pretty much impossible for a fighter.

A few problems in the woodworks, what kind of navy could afford this solution? A large sized container ship can't be cheap, the modifications program certainly won't be cheap. While we're on the topic of mods, what makes you think that a container ship can take the stress of the modifications? Sure they carry alot of containers, but that weight is pretty equally and evenly distributed, and most of that container weight keeps the center of balance down low in the holds. Flight decks, elevators, and the airwing itself add a significant amount of weight above the waterline, risking making the ship rather top heavy. Not a good thing.

 

Another concern with the design, how badly will it slow down the battle group. Most of the research I did points out max ship speeds of 25 knots for the Emma Maersk, and the MSC Pamela. However, it doesn't state if thats the max speed attainable while fully loaded. Anyone know the max loaded speed? Another concern would be just how big a target such a ship would be. You mention having massive internal hangar space, that sounds like a very dangerous situation in the event of a fire. Compartmentalization is a critical part of firefighting.

 

While we're on the topic of big hangar decks, hows that going to relate to the flight deck? Will the design be an open hangar design, or closed? Considering the fact that your trying to make this sucker wide enough and long enough to land C-17s, making the flightdeck strong enough to take the punishment is going to be a challenge. Now your caught in a vicious cycle. As the flight deck gets stronger, your hangar deck gets smaller (More and bigger support structures) and your center of gravity creeps ever higher. (Making your ship roll and yaw characteristics even worse) Installing C-27 size lifts and raising them is going to make the problem worse.

 

I don't see the design as unfeasible. However, I do believe that for a navy to implement it, it will require alot of research and development. A whole hell of a lot. If some key and critical questions aren't answered, namely the flightdeck support questions, the Center of gravity concerns, and the damage control concerns, then someone is going to risk buying a real accident prone ship that will wind up being a total embarrassment. This entails another catch-22. I seriously believe that the RandD necessary to make this idea work, and the cost necessary to do it, means that the idea is completely unavailable to all but the largest navies with the biggest purse-springs. Namely, China or the US. The US won't do it. We're way to happy with our proven and tested nuclear boats. They're fast, efficient, proven, and above all, sexy. (You'd be surprised with how much 'Sexy' has to do with budget decisions.) The Chinese on the otherhand, might consider such a ship since they're already interesting Stobar aircraft, they don't have a whole class of carriers already ( if they can be persuaded that your design has better possibilities then the current stobars that they're designing, they might be persuaded to change development tacks) and they already have a good number of container ships and container ship drydocks that could handle the fabrication or conversion of such a ship.

 

In the meantime however, I do believe that the concept of using container ships as emergency helo carriers has been touched on before. I think this idea is quite nifty, and has some promise for smaller navies who may need to rapidly build up some additional capabilities in the event of war. It would be an especially terrific idea if the navies would develop some specialized modular containers to fit such a conversion (such as special modules to provide living quarters for an embarked helo crew and ground troops. Or a field hospital module. Possibly a small ammunition module to store some reloads for the helos armament. A module that can be welded to the ships deck, carrying a VLS package, and the equipment necessary to  interlink it remotely to a nearby warships Air to air system could also prove useful.)

 

You're assuming the larger ship's flightdeck won't have an overhang? Why would such a huge ship not have a flight deck overhang at least as large as the much smaller Nimittz class?

 

Nimitz flight deck width to hull beam ratio: 76.8/40.8m = 1:1.88 = 36m overhang total

Very large CV flight deck width to hull beam ratio: 96.0/60.0m = 1:1.60 = 36m overhang total (I assume only 60.0m hull beam)

 

Available flight deck width = 96.0m. (or ~112m if overhang proportionally equal to a Nimitz class).

 

Besides, a C-27J may need a 40m wide runway; a fighter type could certainly make do with less (as they do on the Nimitz class when slammed violently into the deck by the arresting wires).

 

And then they just sit there?   Where are they rearmed and serviced, and how do they get to this place? What happens to the other aircraft in the pattern while these aircraft taxi around? 

 

No, they use the roughly 4 acres of available empty flightdeck for servicing and rearmament.....or they are taken below if not immediately needed for another sortie. Aircraft are moved around as on any other carrier. Once again I remind everyone: The idea is not to embark more aircraft than on the Nimitz class; which is some 75-80 (helicopters included) these days. There will be a lot more available deckspace than on a Nimitz carrier.

 

 

Then it's a good thing the fighter pilot has some 400m. (around 1300ft.) runway available to come to a full stop. IIRC, a SuperHornet can do it in around 450m.; no modifications to aircraft, zero headwind (wind-over-deck) and no armament. That's the starting point for finding some ways to reduce that distance further (just some 20-25knots wind-over-deck would help a lot).

 

See the dimensions I stated above.  You're going to have a hard time marshalling all these aircraft around to the takeoff spots in 27m of deck width.  

 

Your dimensions are based on wrong assumptions. There would be more like 50-60m deck width for marshalling (though it would split on both sides of the runway.

 

 Again, where is this enormous hangar, and where is all the room required to get aircraft from it to "the runway"?  Sure, you've got more area than a Nimitz, but you're also using a lot more of it to conduct either landings or takeoffs.

The enormous hangar is below the flight deck, I thought that was obvious. And due to the size of the hull will the hangar be at least twice the size of a Nimitz class hangar. Aircraft elevators positioned away from the runway will serve the hangar (just as on any other CV).

 

It will also be able to land safely because of the arresting gear.  Ice and water on the deck has minimal effect for the same reasons -- you aren't relying on the aircraft to launch and stop itself.  And the very nature of arrested landings makes missed approaches safer than flared landings -- if you come in fast or high, you're in a much better position to bolter and go around again when you are already at maximum power, than if you're busy doing everything you can to slow down.

A CATOBAR carrier isn't specifically designed to minimize effects of mishaps like blown tires. It's designed the only practical way it could be, given the space restraints. Space restraints and the emergence of larger, heavier aircraft was the design driver when the angled deck was developed. The procedures around all kind of mishaps, mechanical malfunctions and potential human errors are procedures that have been worked out gradually