Aircraft Carriers

[GTX]

Here's a thought - what if Germany also developed a Carrier or two equivalent to the HMS Furious in WWI - maybe we could see something like Naval versions of the various Albatross and Fokker designs.

Regards,

Greg

[dy031101]

I have a quick question here.

I was fascinated by Merchant Aircraft Carriers of WWII, oilers and grain ships that were fitted with minimal aviation support facilities to provide top cover for civilian convoys until jeep carriers could be available in useful numbers.

But there seem to be conflicting statements on how they were actually used- some said they operated only Swordfish ASW patrols against Kriegsmarine U-boats while others said that they use Sea Hurricanes to chase away Luftwaffe bombers.

Which one is it exactly?

Thanks in advance.

[GTX]

Both - it really depends on the exact class of ship involved.  Grumman Martlets were also used.

Regards,

Greg

[dy031101]

Both - it really depends on the exact class of ship involved.  Grumman Martlets were also used.

Did MACs have catapults?

(Once again, some said they did, others said they didn't.)

[GTX]

My understanding is that the MACs did not have catapults, though some (those based upon Grain carriers) did have a small hangar facility.

The Catapult Armed Merchantmen(CAM-Ships) did (as if the name doesn't give it away) have catapults for their 'one-way' Hurricanes.

Regards,

Greg

[Joe C-P]

There were plans to try to add angled decks to the CVEs, but with the shift to larger, jet-powered aircraft, they just wouldn't have been practical.

The CVLs would have been capable of operating prop aircraft, but I don't know how long they could have supported larger and larger jets.

They would been well suited as ASW or LPH, the angled deck allowing the operation of prop fixed wing ASW or close-support/COIN aircraft. And, of course, the V/STOLs later on, as Spain did with Cabot/Dedalo, would have restored some organic air defense.

[Joe C-P]

Australian (Wasp class assault carrier with F-35B)

Where the hell did that come from?!!!

Regards,

Greg

The Canberras, LHDs being built by Tenix. Not quite the size of the USN's Wasp class, but still pretty substantial, and deemed capable of operating the V/STOL variant of the F-35.

Joe

[Joe C-P]

Here's a thought - what if Germany also developed a Carrier or two equivalent to the HMS Furious in WWI - maybe we could see something like Naval versions of the various Albatross and Fokker designs.

Regards,

Greg

I've thought about this, for the USN. However, their lack of combat-ready aircraft before entering WW1 would have limited the air group.

Germany is a much more likely candidate. Perhaps they would rebuild a battlecruiser damaged at Jutland - the Von Der Tann would be a good possibility. She lost use of all her main guns.

Say they got wind of Furious' rebuild, and decided to do the same. They might repair only the amidships turrets, building a take-off platform forward and a landing platform aft.

Too bad no one makes WW1 ships in plastic in 1/700, or I'd have another project!

JoeP

[GTX]

QUOTE (GTX @ Dec 18 2007, 09:07 AM)
QUOTE
Australian (Wasp class assault carrier with F-35B)


Where the hell did that come from?!!!

Regards,

Greg

The Canberras, LHDs being built by Tenix. Not quite the size of the USN's Wasp class, but still pretty substantial, and deemed capable of operating the V/STOL variant of the F-35.

Joe

I know about the Canberra class - in fact they will mostly be built by Navantia - what I was referring to was the statement of Australia getting Wasps which isn't the case.  As for RAN FAA F-35Bs, keep watching, there is a chance.

Regards,

Greg

[Zen]

Just a few deckplans I've been mucking about with.

[Madoc]

Zen,

Ditch the mid-flight deck elevators.  All the navies which operated carriers found such things to take up far to much hangar deck space than they were worth.  That's why carrier elevators are now always found off to the edges.  Also, if you've got a mid-flight deck elevator and it gets stuck in the down position then you've got a massive hole right in the middle of your already too small operating area.  That ain't good.  Best then to keep them at the edges and give yourself more usable flight and hangar decks.

Madoc

[Zen]

Madoc.

Deck edge elevators are fine if their weatherproof, my work is based on RN preferences of the late 50's and 60's which is where these designs are aimed and they use technology from that era. 
Deck edge at the rear is fine as its well shielded, and fits with the deckplan, but a fore deck edge lift is rather tricky to postion without creating more problems for the deck park.
Elevators have to mate with how aircraft are moved around the deck and hanger.

This is why the 1952 effort had a preference for sketch D, one lift at the edge aft and one inboard fore, same used on CVA-01.

A deck edge lift at the fore on the top design, takes up parking space, interferes with aircraft lined up on the forward catapult, and being the one used for immediate striking down of a recovered aircraft (should that be needed and one must plan for it) must not be obscured by parked aircraft.

Location as sited, frees the lineup for the catapult, or deck park, is accessable to recovered aircraft, and is weatherproof. Yet aircraft can be moved up for immediate launch from it.

The lower design however could move both lifts aft of the 'island' accepting the problems that causes for recoverd aircraft.

[Zen]

Key questions to answer before starting.

1. Take off energy (speed and weight), determine this and you have a calculatable figure for the catapult.
Remember stroke is not track length, a 151ft long track produces only a 130ft stroke.
Acceleration limits for short catapults where 3.5g, and longer ones 6g.

2. Landing energy (speed and weight), this determines pull out distance and in turn is a major factor in angled deck length.
In turn from pull out distance we get stopping zone, and we must factor in nosewheel turning circle.

Your Hook Touch Down Point is idealy 25% of waterline length from the stern, and from this you can calculate on the assumption that you know wire spacing, and that the catapult forward is clear of the stopping zone.

For a distance from HTDP to angled deck end of 340ft (220ft pullout, and 24ft wire spacing, wire1 being across HTDP), assuming a 8.5 degree angled deck and a catapult length from blast deflector to bow of 270ft.
This 270ft figure includes:-
10 from bow to track start
220ft of track = 151ft stroke length (the rest is slack and stopping distance)
40ft to end of blast deflector, this length also incudes the CALE positioning system in it, which starts at track stop.

We remove bow overhang of the waterline, say 25ft to get 585 which is 75% of waterline length. Ergo waterline is 780ft, and assume a 30ft overhang at the stern which means overall length (excluding bridal catcher) is 835ft. This seems a minimum, where the forward catapult begins on the centerline (blast deflector) tightly close to the angled deck and is angled out to port at about 5 degrees.

3. to Gallery deck or not to Gallery deck?
A gallery deck adds a lot of room for stuff in a carrier, sitting as it does above the hanger deck, inlcuding the catapult troughs and arrestor machine rooms.
BUT it adds a lot of topweight on a hull. The Clemenceau class don't have a gallery deck, nor did the modernised Essex's as far as I can tell.
Weight pushes a hull down in the water, and for deck edge lifts the minimim freeboard to the hanger deck floor seems about 23ft with a preference for 24ft.

The reason HMS Victorious did'nt get a deck edge lift is due to the 14ft freeboard to the hanger deck floor, but she did have a gallery deck.

In the projected Implacable modernisation, the 23.5ft freeboard to the upper hanger permitted deck edge lifts but to cope with this and a gallery deck demanded beam at the waterline be raised to 110ft for stability reasons. Even then the gallery deck would be cramped with a low ceiling!

Thus we can see why modernised Essex's and Clemenceau could get away with such narrow beam in the waterline and still have deck edge lifts, they did'nt have so much topweight pulling the center of gravity up in the hull. Topweight in the form of a gallery deck. So they had less volume in the form of less decks and thus less space to store or place resources, people and equipment.

This also explains why HMS Hermes has a deck edge lift and why she has a large island, no gallery deck, because it could'nt be fitted to a hull of 90ft beam in the waterline.

Its of note that Clemenceaus had to be bulged for stability and increased torpedo protection.

The further benefit of a gallery deck is that in HMS Victorious they housed half the AIO (operations rooms) down there beneath the island, and this permitted a smaller island taking up less of the flightdeck.

[dy031101]

In the "Southern Sea Eagles - The Alternative RAN FAA" thread, Lawman suggested an enlarged Invincible carrying around 20 Sea Harriers, around eight Sea Kings, and perhaps even a few fixed wing AEW STOL aircraft in place of some of the Sea Kings.

Candidates in his suggestions included the Shorts Skyvan/330/360 or GAF Nomad, and I was reminded of Do-128.  There are some figures available about the land-based runway requirements (610 metres for Skyvan and Do-128, 700 for Nomad) for the aircraft mentioned- could those figures be improved by adding devices such as reverse pitch propellers to those machines, or do they already come equipped with such items?

Then I was also reminded by elmayerle about MU-2 being a pressurized aircraft option- I remembered some people (not on this forum) criticising an AEW version of V-22 for taking an unpressurized airframe as a basis.

Assuming an AEW equipment fit at least equal to the Sea King AEW, a 12-degree skijump on the carrier, and devices that can reduce landing distance (if the aircraft don't already have them), how long does the flightdeck have to be for safe operation?

[jcf]

As soon as I can lay my hands on a Revell Ark Royal, I'll make a start on my Olympic class liner based carrier.

I'm working up a similar notion using a 1/350th Titanic kit.
Haven't yet decided on era or aircraft complement.

Jon