AHC - Smallest carrier possible with ability to operate F/A 18

[La Rouge Beret]

I am conducting research into a TL where the F/A 18 Hornet is able to operated from a carrier operated from a medium power navy. This would including the Spanish, RAN, RCN and or the RN if they opt for a conventional replacement instead of the Invincible class.

 

[Matt Wiser]

A ship the size of Charles de Gaulle should be able to. The French Navy seriously considered leasing Hornets to fly from Foch and Clemenceau pending the arrival of Rafale, but Dassault used its pull to scuttle the notion. Both Midway and Coral Sea operated Hornets after the F-4s went away, so no problem there.

 

[DD951]

The French actually conducted carrier trials of the F-18 aboard Clemenceau, but found that although the Hornet could technically operate from the ship, it couldn't carry anything resembling a useful load when doing so (just a pair of Sidewinders, the gun ammo, & just barely enough gas to get up to altitude & fuel up from a tanker.) Trying to fly one off a Centaur would probably run into the same problems.

Not sure what led to the USN determining that the F-18 couldn't safely operate from an -27C Essex, so I believe the smallest carriers that would be capable of flying the Hornet would probably be Eagle & Ark Royal III. I suppose in theory that the F-18 could operate from the modernized Victorious following the Phantomization refit, but I don't know enough about the relevant ship & aircraft characteristics to be sure.

 

[Matt Wiser]

Probably because by the time the F/A-18 would be ready, all of the Essex-class ships (except for Lexington) would be either in mothballs or scrapped. Which begs the question: did Hornets fly off of Lady Lex during her time as a training carrier? There's pics of A-6s, A-7s, and S-3s doing carquals on Lexington in the '80s, from the Detail and Scale book about the Lexington, so it may have happened. But then again, if it's carquals, no weapons load.

 

[DD951]

Probably because by the time the F/A-18 would be ready, all of the Essex-class ships (except for Lexington) would be either in mothballs or scrapped. Which begs the question: did Hornets fly off of Lady Lex during her time as a training carrier? There's pics of A-6s, A-7s, and S-3s doing carquals on Lexington in the '80s, from the Detail and Scale book about the Lexington, so it may have happened. But then again, if it's carquals, no weapons load.

Haven't heard anything about Hornets & Lexington.

However, somewhere in Friedman's carrier book, there's a mention that during the Reagan buildup in the early 80s, the administration wanted to reactivate Oriskany & perhaps one or two others, but abandoned the idea after the Navy's feasibility study said they weren't capable of operating modern aircraft. Didn't mention whether it was a flight deck issue (weight or heat possibility), hangar height/space, incompatible take-off & landing characteristics, needing a bigger catapult than the ship could take, or something else.

 

[Matt Wiser]

That's come up before: probably noting that the Navy no longer flew the F-8 and A-4, and that only USMC squadrons at the time flew Skyhawks. I'll bet that all of those issues came up in the discussion about reactivation.

 

[La Rouge Beret]

Essentially what I am considering is a replacement to the Majestic class carriers that were popular during the Cold War.

In the early 1960’s the governments of Canada, Australia, Netherlands and possibly India look at a replacement for their existing carriers in order to operate the larger and heavier fixed wing aircraft coming into service.

I would think a carrier around 40,000 tonnes would prove sufficient, either a down sized Midway / Audacious class or an enlarged Clemenceau class. This would also have the advantage of using better steel than both of those vessels and taking advantage of the improvement in technology in the period.

Initially I imagine they would be operating the Scooter or possibly the F-4, but in the 80’s they transition to the F/A 18. At this stage I am uncertain about the number of aircraft available, but I thought something in the order of approximately 20 + Hornets would seem right.

 

[Matt Wiser]

If crew size is an issue, a CDG-sized ship would do. Air wings would vary among operators, though.....If India buys one, then it's Super Etendards, since there's no Soviet fixed-wing type available, and their ties to the U.S. were strained. Canadian, Aussie, Spain might buy Hornets for fighter/attack work, E-2C for AWACS, and Lockheed might finally get customers for the S-3 (a sale for 30 Vikings to West Germany in the mid '70s fell through for some reason).

 

[Riain]

This is a table of catapults I scrounged a while ago, I think the Clem and Foch used British BS5 catapults, the 150' stroke model. The BS5 can launch 25,000kg to 91kts, which is a touch lift for a Hornet, if the ship can't make up the remaining speed and wind over deck then the plane isn't going to fly. I think for a margin of safety the 199' BS5A that was the waist cat on the HMS Eagle and Ark Royal, or the US C11 and C13 cats. this is why the French kept the Crusader in service for so long.

Type....Shuttle Run..overall Length.........Capacity...........Classes
USN:
C11-2.....150ft...........203ft.........39,000lb@136kt ....Essex, Midway & FDR waist cat 1960s
.................................................7 0,000lb@108kt

C11-1.....215ft ..........240ft.........45,000lb@132kt...Kitty Hawk 1960s, Oriskany, Coral Sea (all),
.................................................7 0,000lb@108kt...Midway & FDR bow cats

C13........250ft ..........285ft.........78,000lb@139kt ..Enterprise, America 3, Kitty Hawk 1970s

C13-1.....310ft...........345ft.........?@?........... ..........Nimitz, America 1


RN:
BS5........151ft...........220ft.........35,000lb@ 126kt...Eagle 1964 (bow), Ark Royal (bow) 1970
.................................................5 0,000lb@91kt

BS5A......199ft...........268ft.........35,000lb@1 45kt...Eagle 1964 (waist), Ark Royal (waist) 1970
.................................................6 0,000lb@95kt

BS6........250ft...........320ft.........70,000lb@ 100kt...CVA01

BS4.....103ft...160ft...40,000lb@78kt...Mod Majestic, Hermes 1959
................................30,000lb@110kt

BS4M...112ft...169ft...?........................Melbourne 1971+

BS4C ...139ft...175ft...35,000lb@99kt...Centaur 1958

 

[La Rouge Beret]

Yeah in essence I think a ship around the displacement of Charles De Gaulle would be about right.

My ultimate thoughts would be with a run of 5 aircraft carriers being constructed, the RN may add an additional two units, possibly with nuclear propulsion, to replace the Audacious class. Which I imagine would be in lieu of the Invincible class, this of course may butterfly away the Falklands.

 

[La Rouge Beret]

This is a table of catapults I scrounged a while ago, I think the Clem and Foch used British BS5 catapults, the 150' stroke model. The BS5 can launch 25,000kg to 91kts, which is a touch lift for a Hornet, if the ship can't make up the remaining speed and wind over deck then the plane isn't going to fly. I think for a margin of safety the 199' BS5A that was the waist cat on the HMS Eagle and Ark Royal, or the US C11 and C13 cats. this is why the French kept the Crusader in service for so long.

Type....Shuttle Run..overall Length.........Capacity...........Classes
USN:
C11-2.....150ft...........203ft.........39,000lb@136kt ....Essex, Midway & FDR waist cat 1960s
.................................................7 0,000lb@108kt

C11-1.....215ft ..........240ft.........45,000lb@132kt...Kitty Hawk 1960s, Oriskany, Coral Sea (all),
.................................................7 0,000lb@108kt...Midway & FDR bow cats

C13........250ft ..........285ft.........78,000lb@139kt ..Enterprise, America 3, Kitty Hawk 1970s

C13-1.....310ft...........345ft.........?@?........... ..........Nimitz, America 1


RN:
BS5........151ft...........220ft.........35,000lb@ 126kt...Eagle 1964 (bow), Ark Royal (bow) 1970
.................................................5 0,000lb@91kt

BS5A......199ft...........268ft.........35,000lb@1 45kt...Eagle 1964 (waist), Ark Royal (waist) 1970
.................................................6 0,000lb@95kt

BS6........250ft...........320ft.........70,000lb@ 100kt...CVA01

BS4.....103ft...160ft...40,000lb@78kt...Mod Majestic, Hermes 1959
................................30,000lb@110kt

BS4M...112ft...169ft...?........................Melbourne 1971+

BS4C ...139ft...175ft...35,000lb@99kt...Centaur 1958

So possibly an upgrade of the catapault system in the 1980's during a refit to operate the Hornet or would the deck size be the largest constraint?

 

[DD951]

Yeah in essence I think a ship around the displacement of Charles De Gaulle would be about right.

My ultimate thoughts would be with a run of 5 aircraft carriers being constructed, the RN may add an additional two units, possibly with nuclear propulsion, to replace the Audacious class. Which I imagine would be in lieu of the Invincible class, this of course may butterfly away the Falklands.

CdG would be a bit on the small side, but sounds about right, especially considering the budgetary & manpower constraints the likely customers would be facing.

Not sure if there are any historical 'never-were' designs from the time period in that ballpark- from some stuff I saw on the Warship Projects Board a few years ago, the French were originally planning on building a third, notably larger carrier in the early 60s, that was 45,000 tons, & I believe was sort of an enlarged & improved Clemenceau, Verdun although the Canadians & the Dutch might be a little leery of that, as when the RN evaluated Clemenceau and enlarged versions thereof as a possibility in the process that resulted in CVA01, they were rejected pretty quickly on the grounds that by RN standards, it had dangerously poor stability & seakeeping.

Although CVA01 would be bigger than what you're looking for, the Genocide's article on the design notes that the design the RN went with was on the medium of the spectrum studied, with the smallest at 42,000 tons. However, the smallest design had a very tiny airgroup, 27 aircraft, but capacity rose quickly as size grew, with the historical CVA01 carrying 50.

Kind of suspect that the French, in order to get what they did out of their designs, they sacrificed survivability, endurance, aviation magazine capacity, and/or seakeeping qualities as a trade-off against a bigger airgroup.

Should also note that the historical Midway was built to WW2 instead of Cold War design standards, and although reconstructions kept them capable of operating modern aircraft, they were grossly overweight as a result, and according to several people who served on them over at the Navweaps board, were terrible seaboats as a result of that weight gain, rolling heavily & shipping water over the flight deck in any sort of heavy weather.

 

[Riain]

So possibly an upgrade of the catapault system in the 1980's during a refit to operate the Hornet or would the deck size be the largest constraint?

I think just sheer bulk to both mount such a powerful catapult and provide both the steam to drive it and high weights as well as drive the ship fast enough. The Ark Royal struggled to do both in the 70s although I suspect the Eagle would have had an easier time of it.

Interestingly the RAN lengthened the Melbourne's cat by 9' in 1971, it didn't provide any extra oomph but gave another 8% of time/space to impart the existing oomph (that's the scientific term by the way) which reduced stress on everything; ship, plane and pilot. However I think the big changes in length, about 50' in BS4-BS4A and BS5-BS5A meant that more steam was needed.

 

[NothingNow]

The French actually conducted carrier trials of the F-18 aboard Clemenceau, but found that although the Hornet could technically operate from the ship, it couldn't carry anything resembling a useful load when doing so (just a pair of Sidewinders, the gun ammo, & just barely enough gas to get up to altitude & fuel up from a tanker.) Trying to fly one off a Centaur would probably run into the same problems.

It sounds like that's an issue with the catapults and ship's machinery more than anything else (although you'd definitely want a higher T:W ratio than the standard F404s could provide as a safety precaution, RM12s or F414s would be the best fit.)
So you could possibly fly Hornets off a ~24,000 ton carrier, but it'd need a serious refit, and specially modified aircraft to be remotely practical.

Anything with a decent sized catapult and powerplant north of 30,000 tons displacement seems like better minimum criteria though.

Not sure what led to the USN determining that the F-18 couldn't safely operate from an -27C Essex, so I believe the smallest carriers that would be capable of flying the Hornet would probably be Eagle & Ark Royal III. I suppose in theory that the F-18 could operate from the modernized Victorious following the Phantomization refit, but I don't know enough about the relevant ship & aircraft characteristics to be sure.

I'd say as a general rule, if you could safely fly Phantoms off a carrier, you can easily fly Hornets off of it. They are that much lighter, with less wing-loading and a much better thrust to weight ratio after all.

But that would point to the Audacious-class being the smallest really suitable carriers IOTL. They'd be a perfect fit too, and could definitely do without the Spey Phantom's trick nosewheel.

 

[Riain]

It sounds like that's an issue with the catapults and ship's machinery more than anything else (although you'd definitely want a higher T:W ratio than the standard F404s could provide as a safety precaution, RM12s or F414s would be the best fit.)
So you could possibly fly Hornets off a ~24,000 ton carrier, but it'd need a serious refit, and specially modified aircraft to be remotely practical.

Anything with a decent sized catapult and powerplant north of 30,000 tons displacement seems like better minimum criteria though.


I'd say as a general rule, if you could safely fly Phantoms off a carrier, you can easily fly Hornets off of it. They are that much lighter, with less wing-loading and a much better thrust to weight ratio after all.

But that would point to the Audacious-class being the smallest really suitable carriers IOTL. They'd be a perfect fit too, and could definitely do without the Spey Phantom's trick nosewheel.

Not just the trick nosewheel, also the extra 6000lb or so of extra thrust from the Speys was needed to operate from the 150' and 199' catapults on the Ark Royal with any weaponload. Another trick the F4K did that USN did not was have a heavy bring back capability, it could land with considerably more unused ordnance than USN Phantoms because the magazines on the Ark were considerably smaller as was the fleet train.

 

[La Rouge Beret]

Not just the trick nosewheel, also the extra 6000lb or so of extra thrust from the Speys was needed to operate from the 150' and 199' catapults on the Ark Royal with any weaponload. Another trick the F4K did that USN did not was have a heavy bring back capability, it could land with considerably more unused ordnance than USN Phantoms because the magazines on the Ark were considerably smaller as was the fleet train.

How about the RAN purchases HMS Eagle for the cost of the proposed refit in 1968, rather than upgrading HMAS Melbourne?

I am going to work under the assumption the RAN would still use the Scooter, although a big part of me would love to see RAN Phantoms.

 

[Riain]

In 1968 the RAN rejected the Hermes on the grounds that it was too expensive to run, regardless of what capability improvements she would undoubtedly bring with her size, speed and 2 catapults, one being the 145' BS4A. Here's a pic of one of our Skyhawks on Hermes.



If the Hermes was too expensive to run then the Eagle, with twice the power plant for starters not to mention 1/3 more crew than Hermes (more than double Melbourne) would be way out of reach. Perhaps more importantly it would be vast overkill for a fleet of 20 Skyhawks and 16 Trackers, but to put Spey Phantoms in the RAN (still the only type capable of operating from the Eagle) drastically distorts the Australian force posture.
http://www.flickr.com/photos/41311545@N05/4671366036/

 

[CalBear]

Haven't heard anything about Hornets & Lexington.

However, somewhere in Friedman's carrier book, there's a mention that during the Reagan buildup in the early 80s, the administration wanted to reactivate Oriskany & perhaps one or two others, but abandoned the idea after the Navy's feasibility study said they weren't capable of operating modern aircraft. Didn't mention whether it was a flight deck issue (weight or heat possibility), hangar height/space, incompatible take-off & landing characteristics, needing a bigger catapult than the ship could take, or something else.

Sort of a combination of all of the above. You needed a more powerful catapult, stronger elevators, improved arresting gear, and a host of other improvements.

The Bug at full load is somewhat lighter than the A-3B, and the Skywarrior operated from the Oriskany, but it also was a much slower aircraft, not just at the top end of the envelope, but at the bottom as well. The A-3B stalled at 130mph, the Bug stalls at 195. The difference in energy transfer to the arrestor gear is enormous, and the same goes for the extra energy needed to get the beast into the air with enough speed to keep the pilot from having to take a swim.

Probably the biggest issue was the simple fact that the older ships were conventionally powered. The Navy dislikes conventionally powered carriers for a number of reasons, but one of the biggest is flight operation performance. Even the JFK, which was the last conventional powered CV the USN built, used to lose 6-8 knots of speed while conducting flight operations due to steam diversion to the catapult system. The boilers couldn't generate enough steam for both flight ops AND full speed screw revolutions at the same time (obviously nuclear reactors don't have the same sort of limitations). The problem was even worse with the older Essex and Midway hulls.

 

[DD951]

How about the RAN purchases HMS Eagle for the cost of the proposed refit in 1968, rather than upgrading HMAS Melbourne?

I am going to work under the assumption the RAN would still use the Scooter, although a big part of me would love to see RAN Phantoms.

I don't know about that- unless your TL finds a way to give the RAN a lot more in the way of money & manpower to play with, they're going to have an awfully hard time running the thing & still be able to do everything else they need to do, for the same reason the RAN turned down the US's offer of an Essex or two in the mid-60s, & Eagle would have similar operating costs & manpower demands.

Plus, she would be overkill if you're only going to be flying a couple dozen A-4s, plus an assortment of ASW & AEW fixed-wing birds & helos- if that's all you have to fly from the ship, just upgrading to Hermes would make more sense. Going for the extra size & cost just doesn't make a lot of sense, unless alternate procurement policies result having something extra that would make it worthwhile to do so, such as a joint RAN/RAAF F-4 purchase ILO the historical F-111 buy, perhaps piggybacking on the RN's F-4K order to save some money, or perhaps the US offering a really good deal on some slightly used Crusaders....

 

[Riain]

I've read that the whale used to hit the deck at an actual speed of 87 knots, the rest of the airspeed coming from ship movement and wind over deck.

The more I learn about carriers the more I realise the there are big devils in what appear to be small details; things like top speed, catapult length and power, lift and hangar size. Personally I'd love to see books and website put in catapult lengths, lift size, hangar area before telling me how big it was.