Conversion of V/STOL aircraft-carriers for CAT/STOBAR operations ?

[carvalho2008]

 

[carvalho2008]

 

[carvalho2008]

 

[carvalho2008]

 

[Scott Kenny]

On these "merchant conversions", are you putting the bridge up forward?

 

[carvalho2008]

On these "merchant conversions", are you putting the bridge up forward?

Yes. The bridge is at the bow of the ship. It seems to be the only way to combine both requirements to create a smooth, running deck. It is a hull designed for dual function and to live its entire life in merchant and civil roles. However, it has a pre-conceived design to facilitate military application in case of request. I defend this model for Brazil or other smaller budget countries. A unit could now leave the shipyard for the navy with organic facilities and thus form the doctrine. It is a step forward from what existed in the Aparaho and Scads concept.

 

[Lascaris]

One way for a small CATOBAR catapult avoiding 5he steam plant would b3 putting either an EM catapult or an IC catapult. Of course you need to develop one first...

 

[BlackBat242]

The Spanish Principe de Asturias is 15,912 tons standard, 16,700 tons loaded; 195.9 m (643 ft) long, 24.3 m (80 ft) beam wl.

The Thai Chakri Naruebet is 11,486 tons full load; 182.65 m (599.2 ft) long, 22.5 m (74 ft) beam wl.

 

[Scott Kenny]

One way for a small CATOBAR catapult avoiding 5he steam plant would b3 putting either an EM catapult or an IC catapult. Of course you need to develop one first...

The IC catapult has been done, by the US back in the 1960s or 70s. Powered by a couple of J79s.

 

[carvalho2008]

The IC catapult has been done, by the US back in the 1960s or 70s. Powered by a couple of J79s.

To convert a merchant ship into an aircraft carrier, a ski jump kit is necessary, as well as an auxiliary catapult kit similar to the CE-2 or the STAC proposal. It would be possible to assemble this as a kit and implement it on a ship in 3 weeks. The catapult only complements the ski jump in MTOW takeoffs, that is, it is only activated in a tiny number of critical missions.

 

[carvalho2008]

 

[carvalho2008]

 

[carvalho2008]

 

[F.L.]

I found this artist's view of a fictional type 076 LHD on the sinodefence forum. It's interesting to see that the straight deck configuration could be used with the J-15 while allowing bolters and crash landings without destroying aircraft parked. That makes a pretty compact ship. Probably totally unrealistic, but quite nice.

 

[Scott Kenny]

I found this artist's view of a fictional type 076 LHD on the sinodefence forum. It's interesting to see that the straight deck configuration could be used with the J-15 while allowing bolters and crash landings without destroying aircraft parked. That makes a pretty compact ship. Probably totally unrealistic, but quite nice.
View attachment 710694View attachment 710695View attachment 710696View attachment 710697

It's missing the emergency barrier net, unless they're only planning on having 2x arresting wires.

But yes that's amazingly tightly laid out. I'd still rather have an angled deck, though.

 

[helmutkohl]

I found this artist's view of a fictional type 076 LHD on the sinodefence forum. It's interesting to see that the straight deck configuration could be used with the J-15 while allowing bolters and crash landings without destroying aircraft parked. That makes a pretty compact ship. Probably totally unrealistic, but quite nice.
View attachment 710694View attachment 710695View attachment 710696View attachment 710697

Pretty interesting design.

I am wondering why dot we see any conversions do this in the past.
back then we saw a lot of straight deck ww2 ships being converted to angled decks.

At least for modern day fast jets.. while people often say angled decks allow for simultaneous take offs and landings.
That's only true for large carriers. Smaller ships, even those with angled decks.. are less likely to allow that.
The CdG, Foch, etc.. the catapults are well into the angled landing area, preventing you from doing that.



in which case, why not just use the regular straight deck since you are already limited to take offs and landings at separate times. It will at least reduce the costs of conversion work.

the only potential issue is a greater likelihood of an errant aircraft crashing into the island or parked aircraft

 

[F.L.]

Pretty interesting design.
While people often say angled decks allow for simultaneous take offs and landings.
That's only true for large carriers. Smaller ships, even those with angled decks.. are less likely to allow that

It's suite true.

 

[Dilandu]

Must admit, that recently I came to view "Kiev"-class carriers as nearly optimal idea of heavy multi-purpose warships:



While still being of reasonable size (32.000 tons of standard displacement) they carried:

* Air wing of up to 36 aircraft - both Yak-38 VTOL and Ka-25 helicopters (anit-submarine, maritime reconnaisance, ect.)
* Eight P-500 "Bazalt" long-range (up to 500+ km) supersonic anti-ship missiles, capable of doing low terminal approach, AA fire evasion and implementing ECM. One reload for all launchers was carried onboard (i.e. total number of missiles was 16)
* Two M-11 "Shtorm-M" medium-range SAM with two fire control channels
* Two M-4 "Osa-M" self-defense SAM
* "Viyhr" anti-submarine rocket system (nuclear depth charges), with targeting provided by both towed and bow sonars and helicopters.
* Two five-tube anti-submarine torpedo launchers (21 inch)
* Two RBU-6000 anti-submarine/anti-torpedo depth charge throwers
* Two dual 3-inch AK-762 guns
* Four dual AK-630 CIWS

Basically, those massive cruisers could do everything. Carry out air and missile strikes, hunt submarines, provide fleet air defense, ect. While it isn't always practical to have multi-purpose units, it obviously have several advantages also. With some improvement - like better VTOL and ski-jump for takeoff - they could be truly formidable units.

 

[F.L.]

Equipped with Yak-41s, the Kievs would have been formidable ships.
Or, with a catapult and arresting gears, to embark MiG-29Ks, while retaining only the angled deck.

 

[lancer21]

Agree with F.L., since this is a what-if, if somehow the designers came up with the ski-jump idea during the design phase, they could have built the Kiev as the later 1143.42 project, with a ski-jump and flying MiG-23K instead of the useless Yak-38, while still retaining all the weapons listed by Dilandu. THAT would have been a truly formidable ship.

Was there the remotest possibility that Yakovlev could have finished developing the Yak-41 eartlier so it would have entered service before 1990? It seems not only they were looking at all kinds of configurations for Yak-41 for quite a long time, but also wasting time on projects such as Yak-39. By necessity, this earlier Yak-41 would have the N-019 radar from the MiG-29. And i think i read that in planning the D-30 (F6 from MiG-31?)engine was considered, presumably with a swiveling nozzle like R-79?

So not unlike soviet practice, the early Yak-41 could be built with an existing engine and existing radar. Not quite as capable as the OTL Yak-41 was intended to be, but still lightyears away from the Yak-38.

 

[Scott Kenny]

Pretty interesting design.

I am wondering why dot we see any conversions do this in the past.
back then we saw a lot of straight deck ww2 ships being converted to angled decks.

At least for modern day fast jets.. while people often say angled decks allow for simultaneous take offs and landings.
That's only true for large carriers. Smaller ships, even those with angled decks.. are less likely to allow that.
The CdG, Foch, etc.. the catapults are well into the angled landing area, preventing you from doing that.

View attachment 710930

in which case, why not just use the regular straight deck since you are already limited to take offs and landings at separate times. It will at least reduce the costs of conversion work.

the only potential issue is a greater likelihood of an errant aircraft crashing into the island or parked aircraft

That example picture (CdG?), the bow cat is awfully far to port. Move it ~20ft to starboard and you've cleared the landing area.

Waist cats are always in the way of the angled deck, but allow you to launch 4x aircraft at a time to get alpha strikes up faster.

 

[Yellow Palace]

That example picture (CdG?), the bow cat is awfully far to port. Move it ~20ft to starboard and you've cleared the landing area.

For reasons I don't fully understand, virtually all designs with one bow and one waist cat have the bow cat on the port side, blocking the landing area. That this is consistent across carrier operating nations makes me think there's a good reason, I just don't know what it is....

 

[EwenS]

Look at the Melbourne. Position of forward lift would push the cat right over to starboard meaning:-
1. It is not easy to position aircraft due to the relative location of the island. What is the wingspan of the aircraft relative to available deck width? Think about the wingspan of an S-2 Tracker.




2. It eliminates the parking area at Fly 1. So you actually lose from the layout.





CdeG, while not having the lift has the island much further forward than many carriers. Most likely there are a bunch of Command and control facilities on the decks beneath and inboard of the island. It also looks like you would potentially have problems with aircraft wingspan relative to the island if you move the cat to starboard.

 

[Scott Kenny]

CdeG, while not having the lift has the island much further forward than many carriers. Most likely there are a bunch of Command and control facilities on the decks beneath and inboard of the island. It also looks like you would potentially have problems with aircraft wingspan relative to the island if you move the cat to starboard.


View attachment 711027

Line the cat up on whatever line that is that the helo is centered on.

 

[Manuducati]

Moving the forward catapult towards the centerline would prevent parking any aircraft on the forward deck and bring E-2 wingtip dangerously close to the island.

 

[helmutkohl]

Moving the forward catapult towards the centerline would prevent parking any aircraft on the forward deck and bring E-2 wingtip dangerously close to the island.

I just realized the yellow line indicates the edge of the E-2 wingtips, so everything should behind that.
the white line is the centerline
so if we moved the catapult starboard.. indeed the E-2's wings would clip into the parked aircraft and are dangerously close to the island
so it goes back to my original point.
for small carriers, why not just keep the deck straight, because simultaneous operations wouldn't be possible either way

 

[F.L.]

so it goes back to my original point.
for small carriers, why not just keep the deck straight, because simultaneous operations wouldn't be possible either way

This would be all the more possible as it is not necessary, as on converted straight-deck aircraft carriers, (Essex, Colossus, Centaur...) which were quite narrow. A wider vessel could have one part of the deck dedicated to parking and another to catapulting/landing.

 

[EwenS]

Which brings you back to the “parallel” deck layout of CVA-01. It only had a very shallow 3 degree angled deck. On a ship with a 231ft max beam it becomes possible. The angled deck was designed to get around the narrow axial flight decks of carriers to that point where aircraft had to be parked immediately forward of the crash barrier and the landing area.




And that is a feature that has been expanded on the QE class with its “three lane” deck layout with parking inboard & outboard of the STOVL take off lane. It becomes possible only because the F-35B lands vertically.

 

[H_K]

Parallel deck only works on large 50,000+ ton carriers (CVA-01, CVF).

The priority for a carrier is *NOT* simultaneous landing & recovery but smooth aircraft flow around the flight deck. Most missions are planned in advance with a predictable schedule of launch and recovery events. The only time the 2 come into conflict is when there is an unforeseen need to launch an alert fighter or tanker. That doesn’t take long and in the meantime it really isn’t hard to pause recoveries for a few minutes.

What is more important is to have a large deck park to starboard with pitstop facilities, ie. easy access for ground crew to refuel and rearm aircraft without having to move them for the next launch event and without blocking access to lifts and catapults. Plus space for alert fighters, tankers and mission spares to get to the catapults quickly if needed etc.

If you look at CdG’s flight deck layout for example, it is optimized to quickly recover, rearm and relaunch an alpha strike of ~20 aircraft, with minimum respotting. Anytime during recovery it would be possible to pause landings to quickly launch the alert fighters and alert tanker (parked at the rear of the flight deck) with barely any interruption.

Note: Simultaneous launch & recovery does become more important as your air wing gets bigger, as the potential for concurrent operations increases if you are operating large 40 aircraft alpha strikes that take 45 minutes to recover. Obviously that is a concern for a USN CVN with 80 aircraft but not so much for most smaller/medium sized carriers.

 

[Scott Kenny]

Moving the forward catapult towards the centerline would prevent parking any aircraft on the forward deck and bring E-2 wingtip dangerously close to the island.

Bugger, hadn't realized the E2s were that wide a wingspan (or that CdG was so narrow, whichever). Why didn't France buy Turbo Stoofs?

For general arrangement of new construction, though, I'd make sure that my COD/AEW could clear the island while also still clear of the landing path.

Because there are two separate concerns for air operations:

1. the basic self protection rotation: CAP and AEW off the cats, plane guard helo, ASW helo, tanker?, maybe fixed wing ASW if you have Stoofs or Vikings. This runs pretty much 24/7 unless the weather gets so bad they have to shut down flight ops.
2. the strike package: whether a single big alpha strike like the Nimitz were built around or a more continuous waves of smaller flights like the Fords were built to do (note that Fords can probably also still do an alpha strike). This you only do when needed.

 

[Arjen]

Why didn't France buy Turbo Stoofs?

Because the stoof isn't an AEW&C aircraft.
Turbo E-1 Tracer? The E-1 was a dead end, Grumman had its work cut out to make the E-2 a workable AEW&C aircraft.

 

[Scott Kenny]

Because the stoof isn't an AEW&C aircraft.
Turbo E-1 Tracer? The E-1 was a dead end, Grumman had its work cut out to make the E-2 a workable AEW&C aircraft.

Tracker, Trader, Tracer, all the same airframe. And apparently the Turbo Stoofs have a negative wind over deck requirement on short catapults...

 

[helmutkohl]

I still hope one day that an AEW Osprey gets developed at some point.
the Osprey is already starting to replace the C-2 for cargo

 

[BlackBat242]

Bugger, hadn't realized the E2s were that wide a wingspan (or that CdG was so narrow, whichever). Why didn't France buy Turbo Stoofs?

For general arrangement of new construction, though, I'd make sure that my COD/AEW could clear the island while also still clear of the landing path.

Because there are two separate concerns for air operations:

1. the basic self protection rotation: CAP and AEW off the cats, plane guard helo, ASW helo, tanker?, maybe fixed wing ASW if you have Stoofs or Vikings. This runs pretty much 24/7 unless the weather gets so bad they have to shut down flight ops.
2. the strike package: whether a single big alpha strike like the Nimitz were built around or a more continuous waves of smaller flights like the Fords were built to do (note that Fords can probably also still do an alpha strike). This you only do when needed.

There never were any E-1 Tracers that had been modernized with turboprop engines or a new radar (the E-1 used a modified version of the radar in the Skyraider and Gannet AEW versions).

Besides - the newest E-1 airframe was built in 1961, the type being replaced in Grumman's factory by the E-2.

While S-2s were made until 1968, they would take a lot of modification to convert to AEW aircraft, and would cost much more than just buying E-2s off the assembly line.

CdG began design work in 1986 - was laid down in 1989, and began sea trials in 1999.

 

[Arjen]

Tracker, Trader, Tracer, all the same airframe. And apparently the Turbo Stoofs have a negative wind over deck requirement on short catapults...

Different fuselage, different tail, differrent wing because of the different wing-folding mechanism necessitated by that big radome on top.

In short, a different airframe. I will grant it is related to the Tracker.

A Trader was converted to the Tracer aerodynamic prototype, all of the production Tracers were new builds.

 

[Arjen]

Size comparison of E-1 and E-2 here:

https://www.secretprojects.co.uk/threads/a-technical-speculative-question-if-i-may.26545/#post-271571

 

[H_K]

Size comparison of E-1 and E-2 here:

The difference in wingspan is 8ft (2.5m), but since only the right wing matters from a clearance perspective, the Hawkeye’s impact on the foul deck line is only 4ft (1.25m)… really not that significant.

That’s not the real issue preventing simultaneous launch & recovery, which has more to do with positioning the bow catapult in a way that maximizes flight deck parking. And also as aircraft get heavier this requires longer catapults and longer landing areas (75m cats and 200m angle deck on CdG for example), making it almost impossible to keep the 2 from overlapping on a small/medium carrier with a max flight deck length of ~250m.

 

[Archibald]

E-1 "Stoof with a roof" ? I call it TurboTracer. It's an old idea stuck in my mind since 2006 and my first forays on Internet Aerospace forums. See here ! https://www.alternatehistory.com/forum/threads/red-storm-rising-–-wwiii-in-1986-vignettes.400928/

1- Could have launched from Foch & Clem' - unlike E-2.

2- French flying firemen are still flying Turbo Trackers (La Sécurité Civile loves its Trackers, since 40 years at least)

3- ARA Argentina did landed its own TurboTrackers on good old Foch, rebranded Sao Paulo, in the mid-2000's

4- After a looooong search I've found tantalizing bits that France actually considered AEW Tracers in the 1960's and 1980's (before CdG)
(must have posted my result on this very forum, I'd to search)

First three entries, right here. Two are from the 1989-92 era. Another is a book called "French Fifth Republic & Armement" (so it starts in 1958, with De Gaulle return to power in May - a "legal" and bloodless coup d'état, but a coup d'état nonetheless...)

"tracker""AEW""la marine" - Google Search

France thought of buying E-1B Tracer at both ends of the Clemenceau carriers lives: 1963 and 1988. Interestingly enough the book mentions "they would have needed turboprops ". And the 1989-92 magazines says "Just like the Sécurité Civile TurboTrackers."

So - it could have happened.

My dream Foch & Clem air group
- Mirage G (or a naval F1) interceptor (both were seriously considered from 1968 to 1973)
- A-7E for strike (In 1972 Aerospatiale thought of buying a licence from Vought just to piss off Dassault S.E)
- E-1C TurboTracer, for AEW (almost happened, see above)
- Breguet 941 for Carrier Onboard Delivery (COD - it almost happened: the Breguet landed in 110 meters, not even half a Clemenceau length)

 

[carvalho2008]

Fuselagem diferente, cauda diferente, asa diferente por causa do mecanismo de dobramento de asa diferente exigido por aquele grande radome no topo.

Em suma, uma fuselagem diferente. Admito que está relacionado ao Rastreador.

Um Trader foi convertido no protótipo aerodinâmico Tracer, todos os Tracers de produção eram novos.

 

[Arjen]

When was that proposed? Did it reach production? How would that stack up against an E-2C as it entered French service in 2000?