Small Aircraft Carriers

[Shortround6]

Exhaust is coming out of the blade assembley in the picture, I have no idea of the velocity of the gases but unless you can get them to flow rearward you don't have thrust, at least useful thrust. Trying to push the airplane downwards doesn't count.
At cruise with the waste gate open you don't get much and even here, the angle of the gasses relative to the line of flight of the aircraft is not good.

 

[Admiral Beez]

Wouldn't it be wiser to treat carriers as consumables, make them as small as possible, and make as many as possible? Any thoughts?

They don't get much smaller than this…

 

[Shortround6]

It does help if you can carry a more effective warload than a few slices of last nights meat loaf.
Dropping your lunch on an enemy submarine is not very effective no matter how inedible it was.

 

[Admiral Beez]

https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F2gds8ag2k0s21.jpg&rdt=33249

 

[Howard Gibson]

Exhaust is coming out of the blade assembley in the picture, I have no idea of the velocity of the gases but unless you can get them to flow rearward you don't have thrust, at least useful thrust. Trying to push the airplane downwards doesn't count.
At cruise with the waste gate open you don't get much and even here, the angle of the gasses relative to the line of flight of the aircraft is not good.

The volume flow is 1710/2 in^3/min. All you need is the diameter of the exhaust pipe to the turbocharger.

 

[Shortround6]

The volume flow is 1710/2 in^3/min. All you need is the diameter of the exhaust pipe to the turbocharger.

Exhaust thrust is the mass (fuel and air) times the velocity of the gas squared.

It is the last part that gets tricky. Velocity of the exiting gas stream depends on the restrictions in the exhaust system (internal friction, bends, changes in system cross section) and the pressure of the atmosphere the exhaust stream is pushing against.

Now in order to actually use the thrust the exhaust stream does have to be aligned with the direction of flight of the aircraft. Exhaust pipe end and airflow should be 180 degrees from the direction of flight or as close as in practical.

That exhaust airflow is going straight down, angling the ends of pipes does not make the airflow change direction. It does keep the air from the forward speed of the aircraft from screwup the exhaust trying to get out.
Exhaust thrust applied at 90 degrees to the intended flight path does nothing for speed. Maybe this plane was trying for lift?
Not breathing your engine exhaust is also good.

 

[SaparotRob]

https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F2gds8ag2k0s21.jpg&rdt=33249

I was hoping it was a Grasshopper dropping sandwiches.

 

[EwenS]

LST "carriers"
Only a handful of LSTs were fitted with these temporary flying off platforms (take off only; no landings as back in the WW1 days) for use in the Mediterranean:-

LST 16 received a flying off platform sometime after the Sicily landings in July 1943 and is the LST in the second photo posted by AB in post #62. Side view here. Platform was 220ft x 16ft. It had been removed by June 1944 when she participated in the Normandy landings.

LST 337 was fitted with a flying off platform prior to the Salerno landings. Her deck appears a bit shorter. Again it had been removed by the time she participated in the Normandy landings in June 1944.

LST 386 was another with a platform similar to LST 337 It seems to have been fitted before the landings in Sicily in July 1943, but it had been removed by the time of the Op Dragoon landings in Aug 1944. 337 & 386 were both transferred to the RN in Dec 1944.

LST 906 (which is the LST in the first photo in AB's post #62) was completed on 27 April 1944 and served only in the Med. She was damaged in a collision and while being repaired (sometime between the end of May and the start of Operation Dragoon in early Aug) had the take off platform added, at the cost of the single 40mm mounted above the bow doors. It appears to be a slightly more sophisticated setup with a larger platform at the aft end and canted storage of the L-4s carried to each side. Again reported to be 220ft x 16ft.

Brodie System
Developed in 1943 for use on both land and sea. Used by RAF in Burma in 1944. First sea trial was on a merchantman in late 1943.

The first fitting on an LST was in late 1944. LST 776 (completed 20 July 1944) was converted by Oct 1944. It saw service first at Iwo Jima in Feb 1945 and then at Okinawa in April.

Apparently 25 conversions were planned at one point, but other than LST 776, the only two that I have been able to identify are LST 325 & 393. Both saw service in the Med and NWE and returned home to be refitted, including the addition of the Brodie gear. They were then scheduled for redeployment to the Pacific in 1945. I don't think either of them got there before the war ended.

Note LST 776 was given a ramp for launching the aircraft angled over the starboard deck edge. This must have been removable in whole or part because she had a number of liferafts installed down that side when she was in the Pacific. LST 325 was photographed with the Brodie gear but carrying an LCT(6) on her deck later in 1945.

 

[GreenKnight121]

More Brodie photos:

LST 776 - note that the catapult was for trials only, and was removed before LST-776 departed for Iwo Jima:

LST-325:

 

[SaparotRob]

I can just picture the catapult vigorously launching the Grasshopper's landing gear while the rest of the plane remains on board.

 

[ThomasP]

With Wile E. Coyote at the stick and ACME on the side of the catapult.

 

[Admiral Beez]

So, what's the smallest CATOBAR or STOBAR carrier we can make in WW2 to operate, store, fly off and recover monoplane, piston engined fighter and strike aircraft?

The USN's 495ft Bogue Class CVEs, shown below had a flight deck that was 475ft long.

Even shorter was HMS Audacity's flight deck at 450 feet.

 

[z42]

CVE's were nice little ships, but once you have the hull form and machinery to keep up with the fleet you might get a substantially longer flight deck as a 'bonus' (assuming same complement of aircraft and stores as a CVE)?

 

[EwenS]

AVG-1/ACV-1/CVE-1 Long Island was completed with a 362ft long flight deck, 70ft wide, that proved too short in trials following her completion in June 1941. Here she is as completed.

On 15 Sept 1941 BuShips authorised a forward extension to take it to 418ft. (or 438ft sources vary) x 80ft.Here she is in Oct 1941.

When it comes to the other C-3 based CVE the length of the flight decks varied a bit.
HMS Archer & Avenger class - 410ft or 438ft (sources vary)×70ft
Bogue class - 436ft - 442ft (depending on source) x 80ft. Many of the ships supplied to the RN were given an 8-10ft extension aft to take It to 450ft. Work to achieve that can be seen here.

Modified by Burrards

And for completeness:-
Audacity - 453x60ft
Activity - 498x66ft
Pretoria Castle - 550x76ft
Nairana & Vindex - 502x66ft
Campania - 515x66ft
MAC ship (grain carrier) - 410x62ft (with hangar for 3-4 aircraft)
MAC ship (tanker) - 462x62ft (no hangar, deck parking only so bigger flight deck required)

Sangamon class - 502ft x 85ft
Casablanca class - 474 x 80ft
Commencement Bay - 501 x 80ft

A USN 1952 design for a CVE showed a flight deck 600x85ft on a ship able to do 26.5 knots.

By late war the USN was having to catapult launch heavily loaded aircraft from their CVE much more often, as deck runs were not proving possible so often.

The Independence class CVL (flight deck 552x73ft) and the Bogue class CVE make an interesting comparison, being designed around the same time (late 1941- early 1942). Full load displacement very similar. Similar sized air groups. The difference is the hulls they were based on.

Independence - 600ft cruiser hull designed for 32-33 knots on 4 shafts
Bogue - 492ft merchant hull designed for 17-18 knots on a single shaft.

 

[Admiral Beez]

CVE's were nice little ships, but once you have the hull form and machinery to keep up with the fleet you might get a substantially longer flight deck as a 'bonus' (assuming same complement of aircraft and stores as a CVE)?

Agreed. I think what we want is the smallest possible carrier that has the speed and endurance to keep up with the cruisers and destroyers it will serve alongside. For example, the USN's Independence-class were 11,000 tons, 622ft long (552 ft flight deck) with a top speed of 31.5 knots. I can't find any examples of carriers below 600ft long that could exceed 25 knots.

EDIT - I forgot about IJNS Ryujo and her being 590ft long (513 ft flight deck) and 29 knots. So, this is our target for small and fast carriers.

 

[z42]

EDIT - I forgot about IJNS Ryujo and her being 590ft long (513 ft flight deck) and 29 knots. So, this is our target for small and fast carriers.

I don't think anyone sane wants to look at Ryujo for inspiration on how to design a carrier..

 

[Shortround6]

I don't think anyone sane wants to look at Ryujo for inspiration on how to design a carrier..

A lot depends on expected sea state.

HMS Nairana

 

[Warspite63]

I don't think anyone sane wants to look at Ryujo for inspiration on how to design a carrier..

Though she does make for an excellent cautionary tale.... 'whatever they decided to so, do the opposite!'

 

[EwenS]

The problem with Ryujo was that she was designed as a single hangar level carrier to exploit a loophole in the 1922 WNT which meant she wouldn't count towards total carrier tonnage for Japan as she was under 10,000 tons. (Definition was in Chapter II Part 4). She was laid down in 1929.

The 1930 LNT changed the definition of a carrier.(Article III). So with the ship now counting towards the limit, the IJN decided they needed the maximum out of it. So she was redesigned with a second hangar on top of the original. Shortly after her completion the IJN was experiencing stability problems with other ships, leading to more design changes. They never really cured her stability issues.

 

[Admiral Beez]

I don't think anyone sane wants to look at Ryujo for inspiration on how to design a carrier..

True. The Independence class may be the best of the smallest. But Ryujo cut down to one hangar deck and add an island bridge and we have something useful.