Lessons from Kitty Hawk class for CVF?

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perfectgeneral

Lessons from Kitty Hawk class for CVF?

Lead

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Posts: 446

(12-Jul-2008 06:21:30)

Launched in the Sixties the Kitty Hawk class aircraft carriers were intended for CTOL fast jet operation, but do they have any ideas that you would expect to have been included on a STVOL aircraft carrier like CVF?

Displacement:	60,933 long tons (61,911 t), 81,780 long tons (83,090 t) full load
Length:	1,069 feet (326 m) LOA
Beam:	282 feet (86 m) extreme 130 feet (40 m) waterline
Draft:	38 feet (12 m)
Propulsion:	Eight steam boilers, four propellers
Speed:	35 knots (65 km/h)
Complement:	5,624 officers and men
Armament:	RIM-7 Sea Sparrow surface-to-air missiles, 2 RIM-116 RAM, 2 Phalanx CIWS Automated Anti-Missile/Aircraft Defenses
Aircraft carried:	85

Although CVF doesn't need high speeds for launching (that may change later in service life) and is seeking a substantially smaller crew, there must be some important design points that you feel are overlooked or cut to save money.

I'm interested in the lack of a forward island in the Kitty Hawk design. Is it really necessary?

http://petitions.pm.gov.uk/Want10Destroyers/ http://petitions.pm.gov.uk/4Subs88Months/

BenRoethig

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Posts: 1811

(12-Jul-2008 15:06:36)

CdeG and CVF are really the only design to have in island that far forward. What did CVF learn from Kitty Hawk? Not much really. They're both conventional aircraft carriers that carry aircraft. Beyond that, they have have very little in common. CVF honestly learned more from smaller STOVL ships with a little retail "cut everything to the bone" accounting thrown in.

Zen9

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Posts: 3683

(12-Jul-2008 15:14:02)

Kitty Hawk was what, an improved Forestal right?

Four catapults fed by four lifts, Kitty Hawk had Forrestals lift at the end of the angled deck moved elsewhere so it could be used without interruption of recovery operations IF I reccal correctly.

Rather like the 1952 CV effort, the dictator of the design was operation of the then heaviest fast jets and a nuclear bomber. The angled deck is about the same as the desired length of the '52' in about 690ft, though the ramp leading upto the optimum hook touchdown point (25% of waterline length from stern) is less important than the wirespacing, pullout lengths and nosewheel turning circle.

A maximum airwing of 82 aircraft is likely the aim of the design of Forrestal, producing the given deck area figures.
This covers the following circa 1950s.
24 interceptors
24 fighter all weather
12 strike
12 ASW
8 AEW
2 SAR (planeguard)

Kitty Hawk has both high speed and long stroke catapults, the best of both really, since the catapults can launch quite heavy aircraft at zero WOD.

Its probably a closer comparison to asses CVF to a modernised Midway, CVV or CVA-01.

Split island has been a feature of RN thinking since the 1952 effort for certain.
Medium Fleet CV studies are said to have used it, DNC was very keep on the feature.
CVA-01 started life with it, and bridged the two together, but as the design progressed the gap between them got narrower and narrower until it was just a tunnel.
It ensures that if one island is hit and the funnel it has is destroyed or blocked the other funnel and island permits the ship to still function, both in terms of exhausting some of the propulsion machinary and a having flight control room still available. It also saves on the ammount of uptake ducting through the hull from the machinary. It is also a weight saving feature.

In the 50's the needs of a two deck AIO meant that one had to either choose a large island like on Hermes or Eagle or move the lower room into a gallery deck as in Victorious, which permits a smaller island.

Last Edited By: Zen9 12-Jul-2008 15:28:05. Edited 1 times.

Practica

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Posts: 115

(13-Jul-2008 13:20:24)

Zen9 wrote:
Split island has been a feature of RN thinking since the 1952 effort for certain.

They also were a feature of the late WWII US Fleet Carrier design to replace the Essex's.

http://www.phpbbplanet.com/forum/viewtopic.php?t=2043&start=0&mforum=warshipprojects

Last Edited By: Practica 13-Jul-2008 13:23:21. Edited 1 times.

steevy

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Posts: 137

(13-Jul-2008 17:49:25)

The post war "United States" which was the first "supercarrier" design had a retractable island.The aviators wanted a total flat top but they had to give the sailor types someplace to helm the bloody ship from!The design was interesting because it was pre angled deck(having catapults angled out to port and starboard on basically one big axial deck)the Air Force killed it politically.The Korean War and the usefulness of carriers in general war led to the Forrestal's(they were however still strategic platforms until Polaris let them concentrate on conventional ops).

Last Edited By: steevy 13-Jul-2008 19:20:45. Edited 1 times.

Zen9

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Posts: 3688

(13-Jul-2008 17:52:04)

Curiuous question, what happens to their CV designs if the USN was'nt tasked with strategic nuclear bombing in this era?

Would they still produce Forrestal or a new Essex type?

CVA02

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Posts: 435

(13-Jul-2008 18:54:14)

Zen9 wrote:

Curiuous question, what happens to their CV designs if the USN was'nt tasked with strategic nuclear bombing in this era?

Would they still produce Forrestal or a new Essex type?

The USN didn't need more Essex sized platforms in the post-war era. It is clear that the Midways class carrier were precursors for all post-war carrier construction. If the Forrestal had been canceled much like the earlier United States, it is clear that carrier construction would have ceased in the United States, much as it did in Great Britain. With a pool of 24 Essex class hulls, there would have been no need for further small deck carrier construction, only extensive rebuilds of existing ships - placing the USN in the same position the RN was in during the mid 1960s.

Zen9

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Posts: 3689

(13-Jul-2008 20:12:44)

Yes of course, but it does pose the question would the Essex modernisations be like in our world or more substantial.

bager1968

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Posts: 3048

(14-Jul-2008 01:43:16)

SCB-27: The only proposed reconstruction that Friedman mentions that includes the words flush decked is SCB-27. This proposal preceeded SCB-27A/SCB-27C/SCB-125 or -125A. It was intended to test the features of the United States before she entered service. There were two schemes for SCB-27. The austere scheme A (leaving the superstructure) and the more expensive scheme B (flush decked). Both would have allowed the carriers to operate large nuclear bombers, such as the AJ Savage (45,000 lbs for scheme A) or the Skywarrior (60,000 lbs for scheme B). SCB-27 was dropped because it was too expensive.

SCB-27 was reworked into a less expensive rebuild program that was aimed at allowing the ships to operate jet fighters and attack aircraft. It has almost all of the features of SCB-27. We know of this program as SCB-27A. The irony here is that -27A was twice as expensive as scheme A and half again as expensive as scheme B.

Zen9

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Posts: 3691

(14-Jul-2008 11:36:26)

So presumably if the USN looses its new large carriers, then SC27B becomes more attractive, just in case the bomber mission is regained?

Certainly looking the angled deck of Oriskany it seems too short to recover a heavy bomber like the Skywarrior, let along the comming future of FAW the F4.

bager1968

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Posts: 3052

(14-Jul-2008 21:05:44)

Ahhh, but they did operate the A-3 Skywarrior... but not the F-4 (although more money to completely replace all of the wood deck and install the most powerful C-11-1 catapults would have allowed it).

An A-3 ready to launch from CVA-31 Bon Homme Richard (note the wooden deck).

Zen9

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Posts: 3692

(15-Jul-2008 01:26:14)

I forgot that, but then it comes down to speed and weight at TO and Landing. Especialy landing as it relates to pullout length.

I still think that angled deck is too short for the F4, especialy USN F4's, though Spey powered F4K's might stand a chance, but still not much of one.

CVA02

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Posts: 437

(15-Jul-2008 05:41:58)

Zen9 wrote:

I forgot that, but then it comes down to speed and weight at TO and Landing. Especialy landing as it relates to pullout length.

I still think that angled deck is too short for the F4, especialy USN F4's, though Spey powered F4K's might stand a chance, but still not much of one.

Later models of the Phantom had more reasonable approach speeds, but at that point the last of the Essex class CVAs were being retired. As it turned out, the Crusader remained reasonably credible for the time period and there was no real need to deploy the Phantom from the Essex class. Similarly, the Hawkeye could very well have operated from the Essex class, but the Tracer fleet had more than enough hours left. In the end, it would seem that with modified jet blast deflectors and other minor changes, the F-4 could have operated from the Essex class, had the need actually arisen.

CVA02

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Posts: 438

(15-Jul-2008 05:45:09)

bager1968 wrote:
Ahhh, but they did operate the A-3 Skywarrior... but not the F-4 (although more money to completely replace all of the wood deck and install the most powerful C-11-1 catapults would have allowed it).

An A-3 ready to launch from CVA-31 Bon Homme Richard (note the wooden deck).

Ahhh, but the Vigilante, with its frightening 150 knot approach speed, didn't operate from the Essex class. Early model F-4s also had approach speeds of about 150 knots!

Zen9

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Posts: 3695

(15-Jul-2008 12:01:19)

Oriskany's angled deck on a plan of it I have, though rather small scale, is roughly 523.5ft long, theres about 302.5ft of deck from the last wire to the end.

So I would say this ship needs some substantial rebuild to handle F4s.

Comparison, HMS Ark Royal. 620ft, and from last wire about 368ft.

Looks like theres a difference of roughly 97ft overall, and 67ft from the last wire.

So was Oriskany fitted with DX type arrestors like in Ark Royal?

bager1968

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Posts: 3055

(16-Jul-2008 01:42:49)

No, USN carriers had different, US-designed arresting gear.

Note that if you add an extension of the angle forward of the port elevator, you get more pull-out length.

Here is a view of the forward port side of Oriskany with the elevator removed. You would add a sponson under the flight deck extension similar to that just aft of the elevator.

From: http://home.att.net/~jbaugher1/f4_21.html
"A total of 522 F-4Js were built for the Navy and Marine Corps between December of 1966 and January of 1972. "

"As a result of all these aerodynamic innovations, the approach speed was reduced from 157 mph to 144 mph."

(The conversion of F-4Bs to F-4Ns had some, but not all of the improvements of the F-4J, and thus did not experience the drop in landing speed.)

From the book 'Phantom from the Cockpit - Flying the Legend':
"The RN's F-4K (FG.mk 1) approaches were determined at around 19 degrees AoA, speed being 137Kts IAS at a weight of 36,000lbs."

This info is puzzling, as the F-4K was designed to lower approach speeds even more than the F-4J, upon which it was based, and the above figure is 155.7 mph.

From http://home.att.net/~jbaugher1/f4_22.html
"In addition, the Spey was able to provide more bleed air for the boundary layer control system, which would permit slower approach speeds."

"In the interest of achieving slower carrier landing approach speeds, larger wing leading edge flaps were fitted and boundary layer control was applied. The amount of anhedral on the stabilator was reduced, and slats were provided on the stabilator leading edge. 16 1/2 degree drooped ailerons were fitted, which is a fancy way of saying that with gear and flaps down, the neutral position of the ailerons automatically changes to 16 1/2 degrees downward deflection."

I think perhaps the speed cited in 'Phantom from the Cockpit - Flying the Legend' is actually an unconverted "mph" speed, which makes sense considering the take-off figures from the same book:
"Weight - Cat end speed - Wind over deck - Total 'speed' - Calculated Min Launch speed
44300lbs 121Kts 18Kts 139Kts 127Kts
44800lbs 109Kts 22Kts 131Kts 130Kts
44900lbs 107Kts 26Kts 133Kts 130Kts
45100lbs 119Kts 17Kts 136Kts 131Kts"

With 25% more weight, min launch speed is 7 knots lower than approach speed?

137 mph = 120.6 kts

Last Edited By: bager1968 16-Jul-2008 02:04:13. Edited 2 times.

Zen9

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Posts: 3698

(16-Jul-2008 02:03:41)

Yes Oriskany could take a longer angled deck assuming its angle might be reduced somewhat to ensure the sponson is too great and you want more usable width on the angled deck.

Idealy we'd shunt that whole island outwards too.

With 25% more weight, min launch speed is 7 knots lower than approach speed?

Hmmmm....at launch you have the engines in reheat adding to acceleration, for the F4K thats going from a SSL thrust combined of 24,500lb to 42,500lb in reheat. While on approach reheat is only lit to ensure acceleration to keep flying speed if the wires are missed.

jlyons97

CVA air groups in the '50s

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Posts: 1589

(16-Jul-2008 05:46:56)

Zen9 wrote:
Kitty Hawk was what, an improved Forestal right?

Four catapults fed by four lifts, Kitty Hawk had Forrestals lift at the end of the angled deck moved elsewhere so it could be used without interruption of recovery operations IF I reccal correctly.

Rather like the 1952 CV effort, the dictator of the design was operation of the then heaviest fast jets and a nuclear bomber. The angled deck is about the same as the desired length of the '52' in about 690ft, though the ramp leading upto the optimum hook touchdown point (25% of waterline length from stern) is less important than the wirespacing, pullout lengths and nosewheel turning circle.

A maximum airwing of 82 aircraft is likely the aim of the design of Forrestal, producing the given deck area figures.
This covers the following circa 1950s.
24 interceptors
24 fighter all weather
12 strike
12 ASW
8 AEW
2 SAR (planeguard)

Kitty Hawk has both high speed and long stroke catapults, the best of both really, since the catapults can launch quite heavy aircraft at zero WOD.

Its probably a closer comparison to asses CVF to a modernised Midway, CVV or CVA-01.

Split island has been a feature of RN thinking since the 1952 effort for certain.
Medium Fleet CV studies are said to have used it, DNC was very keep on the feature.
CVA-01 started life with it, and bridged the two together, but as the design progressed the gap between them got narrower and narrower until it was just a tunnel.
It ensures that if one island is hit and the funnel it has is destroyed or blocked the other funnel and island permits the ship to still function, both in terms of exhausting some of the propulsion machinary and a having flight control room still available. It also saves on the ammount of uptake ducting through the hull from the machinary. It is also a weight saving feature.

In the 50's the needs of a two deck AIO meant that one had to either choose a large island like on Hermes or Eagle or move the lower room into a gallery deck as in Victorious, which permits a smaller island.

You need to revisit your sources re a '50s Forrestal air group.

Recall Forrestal and her sisters (plus the Midways, plus some Essexs) were CVAs. As such they did not have organic ASW aircraft. Their AEW component was a four plane detachment, as it had been since these airplanes went to sea and remains so today.

Fighters: One VF, one VF(AW). In the '50s this might be one of several combinations depending on the year.(FJs, F8U, F9F-8, F11F, F4D, F2H, F3H) - total: 24
Strike: One light attack, one medium attack, one heavy attack (A3D, AD, A4D, FJ-4, F9F-8B, F7U). Any nominal fighter in a "VA" squadron was a dead giveaway for a nuclear delivery mission. Total: 36 on a big deck, same on an Essex but no A3Ds (12 AD, 24 A4D instead)
Recce: four plane det (F9F-8P, F8U-1P)
SAR: two helos
EW: four AD-5Q
Night attack: four AD-5N
AEW: four AD-5W

StevoJH

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Registered Member

Posts: 291

(16-Jul-2008 10:09:04)

If the design was based on the experience of other carriers, wouldn't it have been the Two french (foch+degaule) classes, HMS Victorious and the Audacious class?

Zen9

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Posts: 3702

(17-Jul-2008 01:12:55)

jlyons

That information was DNC understanding of the Forrestal at the time of the process of the 1952 CV effort. Remember this is a UK and RN effort to develope the requirements for their own large CV.

AEW requirement was 8, for continous operation in a Tactial Air Unit. The number 24 likely reflects the endurance of FAW aircraft based on four being in the air, similarly with the interceptors. That number 8 AEW would reoccure in later TAU revisions in the 1960s with the end of the DLI mission and the refocus on CAP.
Strike was limited in number due to the understanding they would be primarily nuclear bombers.

StevoJH
The design of the 1952 CV was driven by the need to operate nuclear bombers in strike, this being based around a notional 'navalised Canberra', and this along with the then latest fighter the Scimitar drove the design.

It seems to hit the buffers due to the problems of military drydocks.
Davenport No1 was prefered, but this limited the ship to a maximum of 870ft at the flight deck and even this was pushing things a bit.
Gladstone however was long enough at I understand 1,000ft or so, but not wide enough with a easy entrance to fit a wide beam of ship. They managed with HMS Hood, but she was 104ft in beam, not 116ft.

Because it hits the buffers in being limited to Davenport too many compromises are made for the cost or so it would seem. By cancelation in 1953, its down to just two catapults (one 150ft the other 200ft stroke) and six twin 3" turrets.

Obi Wan Russell

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Posts: 312

(26-Jul-2008 12:11:42)

In the 60s the development of the F-4K for the RN did inspire McDonnell Douglas to offer a similar version to the USN for the Essex class. Known as the F-4L, this aircraft would have been a minimum change version of the F-4K with extra extensible nose leg for greater angle of attack and Spey engines for extra thrust on takeoff. I theory it would have no difficulty in launching from an Essex sized carrier, but the drawback was the wooden flightdeck. Safe operations would have meant almost complete replacement of the flightdeck with a steel structure and water cooled JBDs for the catapults. As has been mentioned previously, the requirement just wasn't great enough, as the Crusader was more than adequate for the task and was available in plentiful numbers. The remaining life of the Essexes was a factor too, though if the six SCB-27C/125 ships and the Oriskany had been put forward for such a modernisation they could have remained viable into the early 80s. For this to hapeen there would have to have been a clear threat to justify a larger carrier force, such as if the USSR had fielded a carrier force of their own form the late 50s onwards. If the Soviets had done this the British Government in the nid 60s would have found it much harder to justify abandoning the RN's Carrier force too.

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Lessons from Kitty Hawk class for CVF?

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