Author Topic: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s  (Read 3558 times)

Offline Volkodav

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From the early 50s the UK worked on a number of 20,000 ton light fleet carrier concepts, including variants designed to operate 28 Scimitar size fighters.  The concepts included new build versions with very large sponsons for an almost parallel port deck and a starboard sponson, out board of the island, large enough to be used as a deck park.  Another sketch that could have been used to upgrade the 1942 CVLs relied on a minimal angled deck and a switch back from concurrent launch and recovery evolutions to separate cycles to be conducted sequentially.  While the size was similar to the 1942 CVLs (obviously for the modernised 1942s) the speed was to be higher at 28kts (re-engining for the modernised ships?).  They were also designed with the possibility of converting them to VSTOL carriers once the technology was perfected and suitable aircraft became available.

There were also larger concepts, up to 30,000 tons, that fell between the modernised Colossus and Majestic class carriers and the reconstructed Victorious that were not so attractive as they were too large to be affordable light carriers and too small to be effective fleet carriers.  This also led to other sketches for 35,000 ton ships of Victorious / Hermes size, it was these that due to scope creep, evolved into the 53,000 (maybe 54-55,000) ton CVA-01 designs.

My supposition is that when the CVA-01 was cancelled and the Escort Cruiser (intended class of five to serve as carrier escorts and independent ASW task force leaders) then the Command Cruiser (Invincible became the primary focus of government to provide the RN with the required command and ASW helicopter (even at the early stages also BEARCAP V/STOL fighter) cover, they instead revisited the 20-25,000 ton Light Fleet and 30-35,000 ton Fleet Carrier options that many design studies existed for.  This would have made sense as many of these concepts were only 10 or less years old, they had been specifically designed to operate larger and heavier aircraft (i.e. deck strength, hanger height, deck park arrangement and size, catapult and arrester gear rating).

Also at this time the RN had conducted a number of studies, such as the one comparing the effectiveness of an all Skyhawk air group on Hermes instead of Sea Vixen and Buccaneer, but also one comparing an evolved P.1127 (the Harrier) to what became the Jaguar.  The results were very interesting with it being determined that eight Jaguars could do everything twelve Harriers could (as well as things the Harrier couldn't), while being considerable cheaper, so much cheaper in fact that the a new generation CTOL Light Fleet Carrier would actually be more affordable than the same number of smaller Through Deck Cruisers with Harriers.

There is also the fact that a modern light fleet carrier could have been designed with sufficient steam to maintain over thirty knots while charging the catapult, apparently the limiting factor on Hermes operating Spey Phantoms.  Even excluding the Phantom the CTOL configuration would have permitted the operation of fixed wing AEW and possibly ASW aircraft, considerable increasing the effectiveness of the fleet.

My scenario is, faced with the data provided by the RN, who (instead of assuming that the utility, flexibility and necessity of a balanced fleet built around carriers was self evident) managed to explain the need for carriers and there cost effectiveness compared to any other options, the British government agreed to a program of smaller fleet carriers to replace the existing ships.  Further more, with the cancellation of Harrier in favour of the cheaper AFVG/UKGV and SEPECAT Jaguar, there was more money freed up for extra hulls meaning carrier number could be maintained at five, the way this was sold to the government was five 30-35,000 ton Fleet carriers (150-175,000 ton total) provided more capability than either six 18-20,000ton escort / command cruisers (108-120,000tons) or three 53-55,000ton Strike Carriers (159-165,000tons total).  The advent of this British program also provided an affordable, modern design that attracted the interest of Australia, Canada and the Netherlands to replace their existing ships.

The first ship was ordered in 1967, laid down in 1969 and commissions in 1975 with subsequent ships laid down (and completed) at three year intervals.  Their entry into service was covered by retaining Hermes in her CTOL configuration, as well as repairing and retaining Victorious, Centaur being converted into a Commando Carrier instead.  The first ship replaced Centaur as a CTOL carrier in 1975, Ark Royal retiring in 1978, Victorious in 1981, Hermes converting to a Commando Carrier in 1984, and Eagle retiring in 1987.  The air group of the first ship, HMS Queen Elizabeth, on entry into service consisted of 12 Phantoms, 12 Buccaneers, 12 Skyhawks, 5 Gannet AEW and 2 Wessex SAR, as did that of the second ship, HMS Prince of Wales.  The third ship, HMS Duke of Edinburgh, introduced Tornado FAW1 and SR1, as well as Jaguar FRS1.

An interesting side effect of this change was the increase in the number of Commando Carriers from two to three permitting a more sustainable maintenance cycle and intern resulting in an improved material condition of the ships and a longer service life.  Also the Type 82 program was expanded to eight ships, one fore each Fleet Carrier and Commando Carrier, while the eight County Class DLGs, were progressively converted into DDHs with Sea Slug being removed and extensive helicopter facilities being installed aft, together with Sea wolf being added with one launcher in B position and a second on the roof of the much larger hanger (four Seakings).  The Type 22 Frigate and Type 42 Destroyer proceeded but with sixteen of each being ordered to provide each group with a pair of each, the major different from reality is they were configured to operate a single Seaking and a single Lynx each.  Eight additional Type 21s were built to a modified design and they provided excellent service as GP / patrol frigates, as well as being successfully exported to Australia.  Finally sixteen Type 23 Frigates were built to replace the remaining Leanders.

Following the completion of the last Fleet Carrier the first of three modified versions was ordered as a replacement for the aging Bulwark, entering service in 1990, 93 and 96.  Then came the new DDHs, these were a return to the late 60s Escort Cruiser configuration, displaced 20,000tons and resembled a more cruiser like Invincible.  Somewhat ironically, when the UK cancelled development of the Harrier the USMC funded its resurrection as they believed the capability to be critical.  The resulting aircraft was a hybrid sharing features of the Sea Harrier and the AV-8A, with all being radar equipped, though they were very much attack aircraft with only a secondary fighter role.  To shore up UK production rights the UK government ordered 100 aircraft with the intention of it entering service with the RAF, however the types suitability for operation from the Commando Carriers was without a doubt, leading to three squadrons being assigned to the fledgling Royal Marines Aviation Group.  An evolved version incorporating many systems and components of the McDonald Douglas AV-8B (more powerful engine, composite structure etc) led to the development and deployment of the Sea Harrier F/A-2, not only with the Royal marines for operation from the Commando Carriers, but also with the RN to operate of the new Escort Cruisers.

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I am actually planning to do a model of something akin to this.  It would be a CVL variant of the Invincible (will be using the 1/350 Airfix kit as the basis - the ski jump will go elsewhere on another project).  Plan will be for it to probably be in RAN service as a HMAS Melbourne replacement.  Back story would have it initially operating Skyhawks though maybe transitioning to navalised F/A-20s with this being seen as offering effective commonality with the RAAF F/A-18s.
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Offline elmayerle

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Presumably one of the larger-wing versions of the F-20 that Tony Chong's book shows; if the basic T-38/F-5/F-20 wing was inadequate earlier on for naval aircraft, I'm sure it would be even more so by this time period.  For something different, use an enlarged and stretched N-250B wing.

Offline Volkodav

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I am actually planning to do a model of something akin to this.  It would be a CVL variant of the Invincible (will be using the 1/350 Airfix kit as the basis - the ski jump will go elsewhere on another project).  Plan will be for it to probably be in RAN service as a HMAS Melbourne replacement.  Back story would have it initially operating Skyhawks though maybe transitioning to navalised F/A-20s with this being seen as offering effective commonality with the RAAF F/A-18s.

Interesting, I have been considering a Wasp / Tarawa based CVS for some time based on my Revel 1/700 Kearsarge.  The idea evolved from the aviation oriented Modified Tarawa put forward as a Melbourne replacement in the 1970s, I have absolutely no idea what the modifications would have looked like but believe they most probably have been something simple, i.e. maybe deletion of the 5" Guns, conversion of accommodation spaces forward of the hanger into hanger space and possibly deletion of the well deck and conversion of there spaces into fuel bunkerage and magazines and aviation spares. 

Looking at a cut away of a Wasp it dawned on me the with the well deck gone machinery space could easily be increased providing more steam generation, or more to the point, more propulsive power (GTs or diesels for COSAG or COSAD) freeing steam to charge a catapult or two.  The big square bow / forward flight deck would easily be able to take a pair of catapults and then it would only be a question of axle or shallow angle deck.  The axle deck was one of the proposals for a new RN CVL in the 50s, the thinking being a light carrier wouldn't be launching huge strikes so could get away with splitting launch and recovery operations, i.e. a CVS conducting ASW ops.  A CAP of a couple of fighters and an AEW would be launched, then a couple of ASW aircraft with may a couple of fighters on deck alert and helos spotted, then the next couple of fighters would launch, the next ASW patrol and AEW as required by endurance and the deck cleared for the first lot to return. 

The RAN could easily have continued operating Skyhawks, Trackers and Sea kings on such a ship as well as acquiring either surplus Tracers or new Hawkeyes.  The ship could even have been sized to operate the F/A-18 which was available at the time such a ship would have been developed.  Using Litton's modular shipbuilding processes they would not have been that much more expensive than the Tarawas or Wasps to build in the US, though I would, as this is a whif, had them built at Cockatoo.

My sensible RAN has a modified Tarawa acquired as a Melbourne replacement commissioning in the early to mid 80s and possibly a second one, based on a Wasp being built in the early 90s, with the rest of the fleet, bar the addition of a second Success clas AOR, pretty much as reality.  My unreasonable RAN has three CVS being ordered up front in the 70s and complemented by two straight LHA or LHD, as well as five, more cruiser like, Invincible class Through Deck Cruisers (each forming the core of an escort group with up to 4 to six destroyers and frigates each).

Offline Volkodav

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I like the idea of the navalised F-20 but with the RAN I would likely go a joint Australia / New Zealand project Kahu and keep the Skyhawks going until replaced by the navalised Gripen that had been developed to operate from the RN and Koninklijke Marine Light Fleet Carriers  ;)

Offline Crbad

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Why not use Rafale? It's already navalised for smaller carriers. Or, dare I say it, F-35?
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Why not use Rafale? It's already navalised for smaller carriers. Or, dare I say it, F-35?

Too late for my scenario - I am talking early/mid '80s and the Rafale wasn't available until the early 2000's.
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Offline GTX_Admin

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Presumably one of the larger-wing versions of the F-20 that Tony Chong's book shows; if the basic T-38/F-5/F-20 wing was inadequate earlier on for naval aircraft, I'm sure it would be even more so by this time period.  For something different, use an enlarged and stretched N-250B wing.


Probably.  One might also consider some of the thrust deflecting ideas that Dornier and Northrop were playing with with the ND.102:



IIRC, one option here was using the thrust deflection/reversal to reduce landing distance and also aiding with takeoff.

Either way, the idea was simply to present a different idea - that of Naval F-20s.. ;)
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Offline GTX_Admin

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I have been considering a Wasp / Tarawa based CVS for some time


Guess where I plan to transfer the ski jump from my 1/350 Airfix Invincible to?  It is planned to go on my 1/350 Gallery Models USS Wasp LHD-1  ;).  And yes, I know that there is a bit of very careful cutting here to be done...

The idea is to create one of the Tarakan-class LHDs as described in Greater Australia.
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The RAN could easily have continued operating Skyhawks, Trackers and Sea kings on such a ship

I like the idea of the navalised F-20 but with the RAN I would likely go a joint Australia / New Zealand project Kahu and keep the Skyhawks going

Fair enough.  Actually a Upgraded Super Skyhawk that incorporated the best parts of the Kiwi Kahu birds and the the Singaporean A-4SU mod with F404 engine could have been a very interesting addition.  Maybe even do them as a 3-way joint Australia-Singapore-New Zealand project with all three adopting the resulting design.

Maybe give the Trackers etc a turboprop conversion as well.
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Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #10 on: January 22, 2017, 01:15:05 PM »

The RAN could easily have continued operating Skyhawks, Trackers and Sea kings on such a ship

I like the idea of the navalised F-20 but with the RAN I would likely go a joint Australia / New Zealand project Kahu and keep the Skyhawks going

Fair enough.  Actually a Upgraded Super Skyhawk that incorporated the best parts of the Kiwi Kahu birds and the the Singaporean A-4SU mod with F404 engine could have been a very interesting addition.  Maybe even do them as a 3-way joint Australia-Singapore-New Zealand project with all three adopting the resulting design.

Maybe give the Trackers etc a turboprop conversion as well.

Exactly, keep the costs down, including in service support costs, while delivering the required capability or more to ensure what really happened never happens.  Basically RAN carrier operations were pretty much doomed from the cancellation of Sydney's planned modernisation in 1954, after just proving how effective even a small carrier could be off Korea, with everything else that happened with Melbourne just delaying the inevitable.  Though I would like to think a UK designed 1950s or 1960s light fleet carrier would have been adopted by the RAN I think, to be honest, the level of political disinterest was such only a complete change in the upper echelons of Australia's major political parties in the 40s, 50s, and 60s could have made a difference.

The only other thing that could have seen this happen would have been if the RAN had somehow acquired carriers earlier and in greater numbers, using them to great effect in WWII.  This would have seen them retain them after the war and need to upgrade or replace them in the 50s and 60s (possibly 40s if the ships in question were escort carriers), meaning the decision date for replacement could have fallen in periods where the capability was seen as indispensable rather then as a costly, non critical, "nice to have". i.e. during the Korean War, Indonesian Confrontation, later stages of Vietnam and after the British withdrawal East of Suez.

I think its a great shame the UK wasn't able to build any new conventional carriers post war as they were clearly the world leaders in innovation at the time.  For example they perceived carriers as the replacement for station cruisers, initially modified 1942 Design Light Fleet Carriers but new ships would have been required in the 60s.  It really is too bad they didn't concentrate on affordable Centaur/Hermes/Victorious sized designs and gone new build instead of reconstruction, as new build ships could have remained viable into the 90s as CTOL carriers when changing strategic conditions would have justified their replacement with a like capability.

Offline Weaver

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #11 on: January 24, 2017, 04:28:28 AM »
If you wanted to add gas turbines to a Tarawa in place of it's well deck, one option to avoid extensive reworking of the superstructure to accomodate new uptakes would be to use electric drive. Replace the steam reversing turbines in the engine rooms with electric motors, then add the GT-driven generators right at the stern with their exhausts going straight out of the transom. There's enough freeboard and well-deck height to put the GT-gennies up near the ceiling, with their intake trunking below them, so that the stern exhausts are above the intakes (thereby avoiding hot gas reingestion).

Stern GTs with straight exhaust and electic transmission were seriously considered during the design phase of the Type 82 destroyer, and some Soviet corvettes had GTs in a similar position, allbeit with mechanical drive.
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Offline Rickshaw

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #12 on: January 24, 2017, 11:09:51 AM »
Putting the exhausts out the stern would pretty much preclude the use of CTOL aircraft though...

Offline Weaver

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #13 on: January 24, 2017, 05:42:33 PM »
Putting the exhausts out the stern would pretty much preclude the use of CTOL aircraft though...

Not convinced of that: some pre-WWII carriers had rear exhausts and their planes were WAY more sensitive to turbulence than modern jets. In any case, if it was an issue, it would be simple to duct the exhausts to the sides externally. Essentially, you end up with a handy stern sponson (which you can use for an extended deck or weapons platform) with the exhausts in the side or rear and intakes underneath it.
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Offline Rickshaw

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #14 on: January 25, 2017, 09:02:54 AM »
Putting the exhausts out the stern would pretty much preclude the use of CTOL aircraft though...

Not convinced of that: some pre-WWII carriers had rear exhausts and their planes were WAY more sensitive to turbulence than modern jets. In any case, if it was an issue, it would be simple to duct the exhausts to the sides externally. Essentially, you end up with a handy stern sponson (which you can use for an extended deck or weapons platform) with the exhausts in the side or rear and intakes underneath it.

True but carrier aircraft are especially sensitive to updrafts over the rear tumbledown.   Side exist means also less chance of reingestion of hot air by the engines.   By all means but the intakes there but not the exhausts!

Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #15 on: January 26, 2017, 10:25:40 PM »
Another possibility that comes to mind is the UK decides the Colossus and Majestic class carriers are too small and that the three groups of Armoured Fleet Carriers are too limited by the age of their design to effectively operate modern aircraft, even with extensive modernisations.  They therefore dispose of them by transfer to allied navies (in particular to barter reductions in Lend Lease debt for materiel, resources and services) and continue with the construction of all eight Hermes, four Audacious and three Malta class carriers.  With the cancelation of reconstructions the RN develops an incremental improvement program to complete the new carriers incrementally in batches incorporating new technologies and features, with only minimal improvements being introduced on already commissioned ships.

The end result is by the time of Korea the RN has cascaded all Armoured Fleet Carriers to allies and sold most of the 1942 Type Light Fleet Carriers class to other nations (including disastrously three Majestics to the Soviet Union), while completing the first four Hermes and two Audacious Class as slightly improved Axle deck carriers.  The remaining Hermes and Audacious were completed through to the mid 50s with interim angled decks, steam catapults and mirror landing systems.  The Maltas were completed to a new design that basically resembled a larger version of the real world reconstructed Victorious incorporating a sponsoned full angled deck and the massive Type 984 Dustbin radar, in addition to the other improvements.

At this point the axle decked Hermes were sold to the allied nations (after modernisation to the interim standard of their sisters) to replace their aging war built carriers, while the RN started to introduce new build light fleet carriers allowing the sale and transfer of the interim Hermes batch.  At this point all four Audacious class were converted into Commando Carriers, their double hangers being ideal for this as one was retained for helicopters (and later Harriers) and the other converted to troop accommodation, equipment stowage and training spaces. 

The RN then settled on a fleet structure of three large strike carriers (with heavy strike aircraft), four large Commando Carriers and eight new build Light Fleet Carriers (with alternate GP and ASW air groups with a mix of air defence fighters, AEW, fixed wing ASW and light strike aircraft).  The new light fleets formed the core of six multi role Escort Groups, that also each included a gun/missile cruiser, an escort cruiser, a DLG, a pair of DDGs and a pair of fast frigates.  The idea being that at any time any one of these groups would form a battle group with each of the deployed Strike Carriers, an Amphibious Assault Group with each of the deployed  Commando Carriers, while the remaining groups would be available for independent operations, including showing the flag, limited interdiction, minor amphibious operations and of course ASW.  This flexibility allowed the Strike Carriers and Commando Carriers to be used sparingly and mostly in local waters or for major exercises, saving money and preserving them for major conflicts, at any time only one or two of each would actually be in operational service with the other(s) in refit or reserve. 

The massive increase in the number and size of flight decks in the RN permitted the retention of fixed wing ASW (either as a limited number with the CVA(L) light attack wings, or a larger number with the CVS ASW Groups on the CVLs), while the provision of hangers and flight decks on the DLGs, DDGs and FF's, as well as the provision of Escort Cruisers, saw a massive increase in the number of ASW helicopters in the fleet.  This in turn permitted a significant reduction in the number of specialist ASW frigates required.  A further flow on from this was the replacement of these expensive ASW hulls with general purpose Sloops to maintain hull numbers as the required levels to meet the RNs significant overseas obligations.  It was also possible to retain a small but significant Coastal Force that was equipped with fast attack craft and missile corvettes.

Finally, the new build Light Fleet carriers were also exported to a number of nations wanting to stay in the carrier game.  Due to their design in the mid 50s and their evolution through the 60s with a specific secondary role of being a spare deck for the Strike Carriers, they had sufficient sustained speed and aviation facilities to effectively operate moderate numbers of large multi role fighter such as the Phantom and were even able to recover and launch any aircraft operated from USN super carriers.  As such they became very effective multirole carriers in their own right in small navies, able to operate a full squadron of large strike fighters, another of large fix wing ASW aircraft (initially Gannet, Alize or Tracker but eventually in the case of the RAN and RCN, Vikings), a flight of AEW (Gannet, Tracer or Hawkeye) and a squadron of ASW and SAR helicopters, in the CVS role.  They could also land some of their ASW aircraft and transfer their ASW helicopters to one of the reserve / commando carriers some of these navies retained to permit a second fighter squadron, or even a larger number of light strike aircraft to be embarked as required, to serve as light attack carriers.  In fact both Australia  (5 CLVs, down from 6 older carriers) and Canada (3 CVLs) chose to operate their Light Fleets in a similar fashion to the RN, placing them in the centre of escort groups with cruisers, destroyers and frigates; while New Zealand (2) and the Netherlands (3) operated theirs in smaller groups, each with a single guided missile frigate and a number of frigates (NZ even buying a couple Tromp Class FFGs specifically for this role.  The biggest coup was probably the sale of four CVS configured Light Fleets to Japan, who operated them with Grumman Super Tigers, Trackers, Tracers and Sea Kings, the Super Tigers being configured solely for air defence.

Offline Kelmola

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #16 on: January 26, 2017, 10:39:18 PM »
The bottleneck in carrier design seems to often be the length and power of the catapult; cf. the extended noseleg required for RN Phantoms despite their more powerful engines compared to US counterparts, or why the French Navy was limited to light planes until CDG became operational.

I trust that even these lighter strike carriers would have at least one catapult able to launch even a fully-laden F-111B ;) It would be rather embarassing to build a "modern" carrier and then realize you couldn't even operate existing aircraft due to weight limits...

Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #17 on: January 26, 2017, 11:38:41 PM »
As I understand it the major limiting factor on British carriers operating standard Phantoms and similar was actually their sustained speed (to deliver the required wind over deck), while generating sufficient steam to regenerate / operate the catapults.  Basically, they could apparently either produce enough steam to operate the cats, or to cruise at sufficient speed to launch large aircraft, not both. 

Interestingly this suggests that Victorious, with her new machinery and higher speed would have been better able to operate large aircraft than Hermes (she was actually referred to as a "Fast Hermes Type Carrier"), also that, if rebuilt, the four shaft Implacables would have been even better.

Extrapolating this assumption on speed and steam generation it is conceivable that a suitable ship could have been designed incorporating additional installed power and more powerful /longer cats.  Deck and lift arrangements (plus of course extra length) could have provided for longer cats, while more modern machinery could have been specified.  Higher temperature and higher pressure steam plants could be a solution, or simply a larger plant, then maybe something more exotic, perhaps COSAG or CONAS.  Another possibility could be a separate steam generation plant solely for the cats and decoupled from the propulsion plant, meaning the carriers propulsion could be sized to provide the required sustained speed for operations without any need to regenerate the cats.

Offline Weaver

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #18 on: January 27, 2017, 12:13:16 AM »
Putting the exhausts out the stern would pretty much preclude the use of CTOL aircraft though...

Not convinced of that: some pre-WWII carriers had rear exhausts and their planes were WAY more sensitive to turbulence than modern jets. In any case, if it was an issue, it would be simple to duct the exhausts to the sides externally. Essentially, you end up with a handy stern sponson (which you can use for an extended deck or weapons platform) with the exhausts in the side or rear and intakes underneath it.

True but carrier aircraft are especially sensitive to updrafts over the rear tumbledown.   Side exist means also less chance of reingestion of hot air by the engines.   By all means but the intakes there but not the exhausts!

Okay, well I can think of four different schemes to take the exhausts out of the back and then round to the side.
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Offline Weaver

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #19 on: January 27, 2017, 12:25:05 AM »
As I understand it, the length of more powerful catapults was the major factor that drove up the size of USN carriers' decks post-war, the huge hangar underneath them being a secondary bonus rather than the design-driver. Once you've got four cats that can launch 60,000lb aircraft plus an angled deck that can land said aircraft, all without subjecting them to unbearable accelerations/decelerations, then you're pretty much up to the size of a Forrestal.
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Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #20 on: January 27, 2017, 01:41:35 AM »
As I understand it, the length of more powerful catapults was the major factor that drove up the size of USN carriers' decks post-war, the huge hangar underneath them being a secondary bonus rather than the design-driver. Once you've got four cats that can launch 60,000lb aircraft plus an angled deck that can land said aircraft, all without subjecting them to unbearable accelerations/decelerations, then you're pretty much up to the size of a Forrestal.

Yes but wind over deck is also critical hence the high sustained operational speeds of even the oil fired super carriers.  Recall also that the US almost ordered a smaller carrier design in the 70s (GTX Whiffed one into the RAN in his alt history) that would have worked but was cancelled, in part because it sacrificed too much in overall capability for what it cost.  With the UK however, as there is no way they could afford a single, let alone the two or three Nimitz sized carriers and the number of aircraft that would be needed for a sustainable capability, the smaller carriers would have to do. 

Once you have settled on two lifts, two cats of sufficient length and a design with sufficient sustained speed to launch a laden F-4, A-3, A-5 etc. the deciding factor on size will be how many aircraft and how many sorties.  Interestingly the Brit carriers were all shorter than the French ones but easily operated larger aircraft, so displacement / volume must factor as well.

Offline Weaver

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #21 on: January 27, 2017, 06:41:14 AM »
Well the Ark Royal was lengthened to almost the length of Clemenceau to take Phantoms: 845ft oa, compared to Clemenceau's 869ft. Both lengths include bridle catchers, so the actual flight deck length is unclear. Also, Ark Royal didn't 'easily' operate heavier aircraft, she barely operated them at much reduced take-off weights, and didn't carry any more than Clemenceau either: final air groups of both types were 38 and 40 respectively. The Ark Royal's extra displacement was mainly caused by her armoured double hangar, which is why she could carry the same number of aircraft but of larger types. This may also have been one reason why the French never bought bigger aircraft, like the Phantom, for the Clemenceau: they probably could have been refitted to launch and recover them, but they couldn't have carried a useful numbers of them.
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Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #22 on: January 29, 2017, 08:11:46 PM »
Just thinking I should have proposed this differently.

Instead of reconstructing wartime construction the UK sold and transferred as much of it as possible, spending their money instead on a rolling new construction program of not only Fleet and Light Fleet Carriers but Cruisers, destroyers, sloops and coastal forces (MTB, MGB, SGB), as well as the submarines and frigates they actually did build.  And not the big block of homogenous designs they planned but failed to build (such as the old one eight ship destroyer flotilla a year) but a constant stream of related but evolving designs build in small batches.  They would have enough commonality that training and support wouldn't be a nightmare, plus could be upgraded to a common standard to a degree if required, perhaps importantly there would be sufficient capacity to build additional examples for export as required.

The whole idea would be to both prevent block obsolescence and to ensure that up to date designs existed to serve as mobilisation designs in the event of a hot war.  It would have worked marginally more expensive in the short term but cheaper in the long run as they could have avoided boom and bust cycles in shipbuilding plus also stayed ahead of the curve with new designs, many of which would be suitable for export.  It would also have permetted the UK to retain their lead in some areas where they fell behind as they found themselves unable to capitalise on their own innovation to the same degree that the US was for example.

Just imagine Centaur and Hermes serving in Korea in axel deck configuration with Sea Vampires then Albion and Bulwark following with interim angled decks, steam catapults and a production version of either the Seahawk or better the P.1052 or P.1081.  The RAN also sends carriers but they are the transferred and renamed Implacable and Indefatigable, equipped initially with Hellcats and Avengers but later with Bearcats supplementing the older types, or even navalised CAC CA15s and Fireflies in NF, FB and ASW versions.  As the war wound down the perfected new build Light Fleets would be entering service with a very Hermes like configuration but more modern machinery and designed from scratch to operate evolved DH110 and or Hawker P.1083, Wyvern, as well as Gannet.  These in production Light Fleets would ideally have been adopted by Argentina, Australia, Brazil, Canada, France, India and the Netherlands instead of buying modernised, or modernising war built Colossus and Majestic types, meaning they could also buy new build carrier aircraft from the UK as well.  They could either have been tailored new builds or surplus RN ships, the later option not dissimilar to what the RN has been doing with frigates and destroyers for decades, selling still useful used ships overseas instead of giving them MLUs.

The larger Fleet carriers could have been built at an even slower rate of one a decade, incorporating all the advances proven on the Light Fleets and due to their size and cost would have been the only ones upgraded to any degree.  Cruisers would have ideally been turned over after about twenty years as well and been supplemented by Cruiser/Destroyers then DLGs to keep costs down.  This would have permitted an earlier and cheaper move into the guided missile age and ship board helicopters with Sea Slug going to sea initially on gun/missile cruisers, then the first couple of Escort Cruisers, while the Cruiser/Destroyers would have evolved into Tartar or Terrier armed, helicopter equipped DLGs. The DLGs would have evolved into Seadart ships while the Escort Cruisers would have either also adopted Seadart, or possibly Tartar (then Standard), while the Gun/Cruisers would have suppressed Sea Slug in favour of helicopter facilities and perhaps Ikara and then relied on replacing their 3" battery with either Tartar (Standard) or possibly Seadart with a pair of waist launchers or a single launcher in B position.  With missile equipped Cruisers, Escort Cruisers and DLGs, and above all Fleet and Light Fleet Carriers with fighters and AEW aircraft there would have been little need for a mass produced DDG like the Type 42 so instead evolved Type 21 fast GP Sloops could have been built with a stranger structure and Seawolf (or Standard for a sexier faster beter armed UK equivalent to the OHP FFG07 class), as well as additional Type 22s.

Offline Kelmola

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #23 on: January 30, 2017, 02:58:28 AM »
As I understand it, the length of more powerful catapults was the major factor that drove up the size of USN carriers' decks post-war, the huge hangar underneath them being a secondary bonus rather than the design-driver. Once you've got four cats that can launch 60,000lb aircraft plus an angled deck that can land said aircraft, all without subjecting them to unbearable accelerations/decelerations, then you're pretty much up to the size of a Forrestal.
Charles de Gaulle has two C13 catapults which are enough to launch 80,000 lb aircraft @ 140kts (conceivably even heavier at lower speeds), and the carrier is only 265m overall length and 42,5 thousand tonnes of displacement verus Forrestal's 325m overall length and 60 thousand tonnes of displacement (admittedly, CDG is nuclear-powered and Forrestal is not).

Of course, in the whiffverse, it might be that the limitations of a steam catapult were realized much earlier and Westinghouse's Electropult system - which was already in advanced testing in 1946 in the OTL - would be adopted instead on the smaller carriers (and why not the supercarriers too). >:D Could be that steam won over electric just because carriers of the time already had excess steam power so it was cheaper, simpler, and did not require much in the way of R&D costs.

Offline M.A.D

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #24 on: February 03, 2017, 06:26:36 PM »
I have been considering a Wasp / Tarawa based CVS for some time


Guess where I plan to transfer the ski jump from my 1/350 Airfix Invincible to?  It is planned to go on my 1/350 Gallery Models USS Wasp LHD-1  ;).  And yes, I know that there is a bit of very careful cutting here to be done...

The idea is to create one of the Tarakan-class LHDs as described in Greater Australia.

Interesting!

M.A.D

Offline Volkodav

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Re: The UK builds a new generation of CTOL Light Fleet Carrier in the 1970s
« Reply #25 on: February 03, 2017, 09:07:17 PM »
I have been considering a Wasp / Tarawa based CVS for some time


Guess where I plan to transfer the ski jump from my 1/350 Airfix Invincible to?  It is planned to go on my 1/350 Gallery Models USS Wasp LHD-1  ;).  And yes, I know that there is a bit of very careful cutting here to be done...

The idea is to create one of the Tarakan-class LHDs as described in Greater Australia.


There's a Gallery Wasp at the LHS, been there for over two years but hasn't dropped in price yet.  Would love to get it but unless I finish some builds first it aint gunna happen.  Maybe the 1/350 New Jersey I started back in the 80s would be a good one to finish to justify another stupidly large kit in the stash.

Offline M.A.D

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The RAN could easily have continued operating Skyhawks, Trackers and Sea kings on such a ship

I like the idea of the navalised F-20 but with the RAN I would likely go a joint Australia / New Zealand project Kahu and keep the Skyhawks going

Fair enough.  Actually a Upgraded Super Skyhawk that incorporated the best parts of the Kiwi Kahu birds and the the Singaporean A-4SU mod with F404 engine could have been a very interesting addition.  Maybe even do them as a 3-way joint Australia-Singapore-New Zealand project with all three adopting the resulting design.

Maybe give the Trackers etc a turboprop conversion as well.

Exactly, keep the costs down, including in service support costs, while delivering the required capability or more to ensure what really happened never happens.  Basically RAN carrier operations were pretty much doomed from the cancellation of Sydney's planned modernisation in 1954, after just proving how effective even a small carrier could be off Korea, with everything else that happened with Melbourne just delaying the inevitable.  Though I would like to think a UK designed 1950s or 1960s light fleet carrier would have been adopted by the RAN I think, to be honest, the level of political disinterest was such only a complete change in the upper echelons of Australia's major political parties in the 40s, 50s, and 60s could have made a difference.


Do we know what this
Quote
planned modernisation in 1954
of HMAS Sydney entailed?

M.A.D

Offline Volkodav

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She was to have been rebuilt to the same basic standard as Melbourne, angled, strengthened deck, steam catapults and upgraded lifts etc. were the guts of it.  Similar to Venerable, Vengeance and Colossus rebuilds.

Offline Volkodav

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I am actually planning to do a model of something akin to this.  It would be a CVL variant of the Invincible (will be using the 1/350 Airfix kit as the basis - the ski jump will go elsewhere on another project).  Plan will be for it to probably be in RAN service as a HMAS Melbourne replacement.  Back story would have it initially operating Skyhawks though maybe transitioning to navalised F/A-20s with this being seen as offering effective commonality with the RAAF F/A-18s.

Something interesting I found on the Atlantic models Facebook page

https://www.facebook.com/AtlanticKits/photos/ms.c.eJxFzFEKACEMA9EbLTaxaXP~;iwmu4u9jmKDsyoZmmMAXB6YroeQFaUPFAY3eAN~;C~;yPwCo5OiwspfRTf.bps.a.1369975346419370.1073741854.213185735431676/1369975926419312/?type=3&theatre


Offline GTX_Admin

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Yes, something like that.  Not quite sure what aircraft to place on it though.
All hail the God of Frustration!!!

Offline Volkodav

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Looking forward it