Larger British light fleet carriers?

[Hood]

From a pilot’s perspective trying to land on Unicorn was far from ideal due to her Aircraft Maintenance Ship origins. The shape of her hull and flight deck aft generated wind shear effects on aircraft crossing her stern. It has been described as like “dropping off a cliff”.

True I would envision dropping the Lighter hangar and gantry at the stern to make run down a little more aerodynamic.

I don’t know if chopping the upper hangar deck to give her a lower profile would help with the airflow or not. But the shorter flight deck length impacts on the ability to operate the USN style “deck load” strikes that became a feature of RN carrier warfare from 1944 and especially so with heavier aircraft.

Agreed, too short really and I can see the Admiralty wanting more length then finding its too heavy so chopping a hangar deck then slimming the hull, the arguing about the 4.5in guns, then how many accelerators, making it wider again, still too heavy, remove some armour, and hey presto an overweight Colossus emerges.
Or the temptation to lengthen and keep the double hangar deck and end up with something like an intermediate lesser-armoured I-series ship, probably can't be built quick enough either way.

 

[NOMISYRRUC]

151ft is 46m
177ft is 54m
199ft is 60.7m
210ft is 64m
250ft is 76.2m

Pressure figures seem off.
I thought BS.4 and BS.5 used 450psi
Though the 1952 studies include 650psi.

157ft seems a curious figure.

It is curious to me too, especially if the 52 metres/171 feet that's usually quoted is the total length.

Perhaps the peculiar length was due to it being the longest catapult that could be fitted in the available space? To be clear I don't know that it was the longest catapult that could be fitted and am speculating that it was.

 

[bobtdwarf]

Out of interest... What were the material defects that plagued Ark Royal?

built with wartime grade steel... she was a ball of rust waiting to happen at the very least and at the worst prone to early metal fatigue/cracking

There was this comment up thread about Bonaventure.

One of the reasons the RCN's midlife refit on the Bonnie went from roughly 4 million dollars to 17 million was they really opened her up.

And found an incredible amount of corrosion. Apparently the shipyards concept of corrosion management consisted of either a coat of paint over it or walling it up and hoping the Customer never noticed it.
During the fifties and sixties the phrase fine British craftsmanship in shipbuilding became an oxymoron it seems.

Do you know whether "being a ball of rust waiting to happen" was a problem faced by many British warships that were built with wartime grade steel?

As far as I know Albion, Bulwark, Centaur, Eagle and Hermes didn't have that problem, but as I know next-to-nothing about the subject it could be due to ignorance on my part. Hermes herself was an operational warship into the 2010s and some of the Colossus/Majestic class were in service for several decades.

What started this off was the statement made by Drachinifel in his Dry Dock Episode 198. That is Ark Royal's poor material condition was due to her hull not being preserved properly, when she was laid up after the war, which allowed a lot of water to get into places where it shouldn't, which in turn created a lot of issues that weren't entirely solved.

He attributed Eagle's better material condition to being launched relatively soon after laying down. (So were all but 2 of the British aircraft carriers that were laid down during the war. The exceptions were Ark Royal and Hermes). Eagle was launched 41 months after being laid down while Ark Royal was launched 84 months after being laid down which is twice as long. (Dates are according to Conway's 1922-46.)

However, Hermes was on the stocks for even longer than Ark Royal (104 months). If she did have severe corrosion problems they didn't stop her remaining in service for the thick-end of 60 years (1959-2017 according to Wikipedia). That or she didn't have them in the first place due to her hull being preserved properly and/or her hull had less wartime grade steel in it because she was laid down 14 months after Ark Royal which might have meant that her hull was less complete when she was laid up.

Ark Royal was built by Cammell-Laird, while Hermes was built by Vickers-Armstrong at Barrow-in-Furness. Could that have been a factor in the ships having better quality hulls? Was the latter have been better at preserving hulls than the former? The other Eagle was also being built by Vickers-Armstrong, albeit at their Tyne yard. If Vickers-Armstrong was better at preserving hulls than Cammell-Laird then the other Eagle might not have had the material defects that plagued Ark Royal.

It was probably a factor on ALL the types like Bonnie.. the colossus etc class since they were built to Lloyd's merchant standards and only expected to last not much longer than 10 years.

They probably didn't that great a job on storing Ark Royal whose modifications did not require massive engineering whereas Hermes was rather radically rebuilt so it is very possible that the most rotten bits of her were replaced during it..she cost more than final conversion costs for Victorious from what I have read.

 

[NOMISYRRUC]

...she [Hermes] cost more than final conversion costs for Victorious from what I have read.

That's what I used to think, but that's before I discovered that they weren't like-for-like costs.

Brown and Moore say Victorious cost £30 million to rebuild, but Marriott and 1960s editions of Jane's Fighting Ships say £20 million.

Marriott said that Hermes cost £37.5 million, but he didn't write that the figure included the aircraft. According to replies by Mr Ian Orr-Ewing the Civil Lord of the Admiralty to questions asked by Mr Emrys Hughes the cost of the ship was approximately £18 million and the initial capital cost of her aircraft was in the order of £10 million.

H.M.S. "Hermes" (Hansard, 25 November 1959)

H.M.S. "Hermes" (Hansard, 25 November 1959)

api.parliament.uk

If memory serves me well part of the difference in the costs of the two helicopter cruiser conversions was that Tiger's included the cost of the 4 helicopters and Blake's didn't.

 

[Archibald]

Which is pretty silly, when you think about it. Imagine if the cost of a Nimitz included cost of the maximum number of (expensive) F-14 Tomcats it could carry.
Same for a Ford carrier with all the F-35s (shudders).
A hundred Tomcats or a hundred F-35s ain't exactly cheap...

 

[NOMISYRRUC]

It was probably a factor on ALL the types like Bonnie.. the Colossus etc class since they were built to Lloyd's merchant standards and only expected to last not much longer than 10 years.

For what it's worth this is part of the opening paragraph of the chapter on the Colossus/Majestic class from Friedman (Page 218) which suggests the service life was expected to have been even shorter than that.

Remarkably, although they were designed as a war expedient (and perhaps for an operational lifetime as short as two years), three of these Colossus class carriers remain in active service, greatly modified, more than forty-five years after having been laid down.

They probably didn't that great a job on storing Ark Royal whose modifications did not require massive engineering whereas Hermes was rather radically rebuilt so it is very possible that the most rotten bits of her were replaced during it.

I'm having one of my blond moments. Does that mean that you agree with Drachinifel?

 

[NOMISYRRUC]

Which is pretty silly, when you think about it. Imagine if the cost of a Nimitz included cost of the maximum number of (expensive) F-14 Tomcats it could carry.
Same for a Ford carrier with all the F-35s (shudders).
A hundred Tomcats or a hundred F-35s ain't exactly cheap...

It has been claimed that the costs that Dennis Healey quoted for CVA.01 in February 1966 included CVA.02, 8 Type 82 escorts and I think the aircraft.

An aircraft carrier without aircraft to carry isn't of much use so including the cost of the initial air group isn't such a bad idea. I do know that the building costs of pre-World War One destroyers included the torpedoes and the ammunition so including the cost of the aircraft in the cost of the ship may have been a continuation of this practice.

 

[NOMISYRRUC]

Building costs that I collected from Jane's Fighting Ships and Leo Marriott's Royal Aircraft Carriers 1945-1990.

​

The building cost of Hermes according to the Hansard report that I quoted earlier on was £18 million for the ship and £10 million for the aircraft.

Refit costs that I collected from the same sources.

​

As noted in an earlier post one of the reasons for Tiger's refit costing more than twice as much as Blake's is that one included the cost of the helicopters and the other didn't.

 

[NOMISYRRUC]

...she [Hermes] cost more than final conversion costs for Victorious from what I have read.

As I wrote in Post 164 Brown and Moore say Victorious cost £30 million to rebuild, but Marriott and 1960s editions of Jane's Fighting Ships say £20 million.

According to the reply by Mr Ian Orr-Ewing the Civil Lord of the Admiralty to a question asked by Mr Emrys Hughes the cost of the refit was nearly £20 million.

H.M.S. "Victorious" (Cost) (Hansard, 2 December 1959)

H.M.S. "Victorious" (Cost) (Hansard, 2 December 1959)

api.parliament.uk

When I read Emrys Hughes I keep thinking Emlyn Hughes former captain of Liverpool and England. Does anyone else?

 

[Archibald]

Liverpool - a pool of livers ? that would make Hannibal Lecter salivating. Is there a Chiantipool somewhere ?

 

[zen]

Hmmmm....1954 estimate of Medium Fleet Carrier was £18 million.
1953 estimate of the 1952 Carrier was £26 million.

1947 estimate of modernisation of Victorious was £5 million
August '50 was £5.4 million
October '50 was £7.7 million
March '52 was £11 million
December '53 was £14.16 million

 

[Archibald]

And by 1959, how much ? (shudders)

 

[bobtdwarf]

It was probably a factor on ALL the types like Bonnie.. the Colossus etc class since they were built to Lloyd's merchant standards and only expected to last not much longer than 10 years.

For what it's worth this is part of the opening paragraph of the chapter on the Colossus/Majestic class from Friedman (Page 218) which suggests the service life was expected to have been even shorter than that.

Remarkably, although they were designed as a war expedient (and perhaps for an operational lifetime as short as two years), three of these Colossus class carriers remain in active service, greatly modified, more than forty-five years after having been laid down.

They probably didn't that great a job on storing Ark Royal whose modifications did not require massive engineering whereas Hermes was rather radically rebuilt so it is very possible that the most rotten bits of her were replaced during it.

I'm having one of my blond moments. Does that mean that you agree with Drachinifel?

I don't know how I lost track of this thread but I did... I don't know, depends on what he said lol

 

[orlovsky]

Do you have any statistics on the catapults fitted to Clemenceau and Foch? I.e. total length, stroke/shuttle run, the launch weights and end speeds?

From French sources, the stroke length was 157ft (47.85m).

In 1962, launch capability was quoted as 33,000lb (15t) @ 110kts / 3.6g or 40,000lb (18.15t) @ 100kts / 3g. This appears to include a safety margin of ~3 knots and translates to a launch energy of ~25MJ.

Later launch capability was quoted as 14t @ 125kts. This translates to 4.4g and ~29MJ, ie. a 15% increase, probably from increasing the steam accumulator pressure slightly.

Porte-avions et catapulte ?

Un élément historique est rarement évoqué : limplantation insolite de catapulte(s) sur certains porte-avions américains. La nécessité des catapultes de lanceme

forummarine.forumactif.com

As posted in the Verdun thread, from the softcover version of Moulin's book on Clemenceau and Foch for Kindle:

He states a more powerful 51,5m (169 ft) bs5 with 110 kts @ 20 metric t replacing a bs4 with 95 kts @ 20t, 110 kts @ 15t and 130 kts @11t. This means the initial bs4 catapult was improved, but also extended from 157 to 169 ft (fitting the 12 ft increments).

As the bs4/bs5/c-11 all derive from the same model, we can make an educated guess at the strength at other weights. It should be about equal to the 199ft bs5a Ark waist cat. Simply subtract 32 kts engine+ship speed from the graph to get catapult end speed:



Approach from the other side: subtract 12-15 kts from the c-11-1 @550 psi:



As for the length, the bs came in 12 ft increments. Stroke length also depended upon the position at the start of the track, and this probably changed over time. The c-11 can be found with a 211 or 205 ft stroke, bs4 came in 145 ft etc (just seems to tend towards 6 ft increments).

 

[H_K]

As posted in the Verdun thread, from the softcover version of Moulin's book on Clemenceau and Foch for Kindle:

He states a more powerful 51,5m (169 ft) bs5 with 110 kts @ 20 metric t replacing a bs4 with 95 kts @ 20t, 110 kts @ 15t and 130 kts @11t. This means the initial bs4 catapult was improved, but also extended from 157 to 169 ft (fitting the 12 ft increments).

Thanks. Can you post a picture of where he says this? I’m curious about exactly how he phrased this change.

 

[orlovsky]

I hope posting this screenshot is ok.

P 27. He gives the length for the initial version with 169 ft, but that contradicts the original manual from 1962. He also mentions a further strengthening of catapults and arrestor gear with the late 70s refits, but no specifics.

Btw, the softcover version has 127 pages, the hardcover may be more extensive?

 

[orlovsky]

If Hobbs information about the catapult capacities is correct (and I'm not sure that it is) Victorious and Hermes could launch aircraft of the same weight at the same end speed in spite of the former having shorter stroke catapults. Therefore, if Hermes could be adapted to operate Phantoms it looks like Victorious could have been too.

Rereading Hobbs, the BS4 on Victorious may have been able to use higher pressure, that might be woth something like 5 kts. Unclear whether the catapults were overhauled, so we might also compare different versions.

What is definitely odd are the two different length bs4 on Hermes giving the same end speed. The F-4 options show two Hermes cats, and the longer one has more power - something like 6-7 kts judging from the added length and the longer CAP.

But at that point the longer catapult was just a plan. Did it really get installed in the late 60s refit?

 

[bobtdwarf]

If Hobbs information about the catapult capacities is correct (and I'm not sure that it is) Victorious and Hermes could launch aircraft of the same weight at the same end speed in spite of the former having shorter stroke catapults. Therefore, if Hermes could be adapted to operate Phantoms it looks like Victorious could have been too.

Rereading Hobbs, the BS4 on Victorious may have been able to use higher pressure, that might be woth something like 5 kts. Unclear whether the catapults were overhauled, so we might also compare different versions.

What is definitely odd are the two different length bs4 on Hermes giving the same end speed. The F-4 options show two Hermes cats, and the longer one has more power - something like 6-7 kts judging from the added length and the longer CAP.
View attachment 687017
But at that point the longer catapult was just a plan. Did it really get installed in the late 60s refit?

Also begs the question: If they could lengthen one of the cats on Hermes why not do it to Victorious and Eagle? I understand how the other cat could run afoul of the island on Hermes and probably would on Victorious but the other might not and they just didn't do it for some cost/planning reason.

 

[BlackBat242]

The main issue was that Victorious, Eagle, and Ark Royal had that inconvenient centerline aircraft lift in the middle of the forward part of the flight deck... causing issues with running the catapult tracks past it.

Hermes moved that lift to the port deck-edge, allowing unfettered installation of the bow catapults.

 

[bobtdwarf]

That would do it.. if you could move to a deck edge starboard on Eagle, as in there is not a structural limitation that precludes it (not referring to the impact it has on the lower hangar since most of that is given over to accommodation in the rebuild); that would be something to keep in mind in future Alt histories.

For Victorious you would need something about the size of the lift on the Illustrious thru deck on the hangar edge so it all remains inside the hull side and I am not at all convinced that would be worthwhile.

EDIT: The Essex/Hancock CVA-19's come to mind here but the port cat is angled and going from memory there is a bit more space between the starboard one and the forward lift.. which they did not use all that often.. so yeah difficult, not impossible but the juice might not be worth the squeeze

 

[EwenS]

The Admiralty looked at installing a side lift on Victorious but quickly concluded that, at hangar deck level, the ship had insufficient freeboard. To have fitted one would have meant it being damaged in heavy seas and/or water entering the hangar deck itself. Not good news for any carrier due to the free surface effect.

In Ark Royal, the side lift only accessed the upper hangar. Again a lack of freeboard precluded it being extended down to access the lower hangar. It had to be removed when she was Phantomised in the 1960s when the waist catapult was fitted over the space it occupied.

The Centaur design began life with a bit more freeboard at hangar deck level allowing Hermes to have aside lift fitted in her redesign.

Trying to move the forward lift on these ships either port or starboard causes all sorts of headaches. There are solid steel walls either side that incorporate the raising/lowering chain gear and compartments outside those just under the flight deck that contain the motors to power them.

And these are “closed hangar” ships with compartments between the hangar wall and the ship’s side. The lifts themselves are more or less on the hangar centreline. So on Victorious, as reconstructed, you have a forward lift 40ft wide sitting in a hangar that is 62ft wide. That lift can only be accessed from forward and aft. So you are limited as to how far sideways you can move it without moving the hangar wall further out for a sufficient distance to take in the lift, and the space you need to manoeuvre an aircraft onto it. And remember, unlike an Essex or a Midway class, this is all structural steel work adding to the overall strength of the ship’s hull.

In Ark & Eagle the forward lift was 44ft wide in a 67ft wide hangar.

Hermes’ hangar was 62ft wide.

The Essex class were far easier to modify postwar because the main strength deck was the hangar deck, not the flight deck as in British carriers. Their hangar was superstructure, and much easier to modify. The biggest problem in them was relocating, where necessary, the various expansion joints in the hangar structure as longer catapults were fitted and lifts moved from the centreline. An Essex was an “open hanger” ship where the hangar itself, except around the island, extended the full width of the ship.

 

[zen]

If memory serves Victorious hanger was 65.5ft wide.

Minimum Freeboard at hanger deck was ideally 24ft or above for a deck edge lift. Victorious had 14ft.
Eagle and Ark had 30ft for the upper hanger.

 

[NOMISYRRUC]

If Hobbs information about the catapult capacities is correct (and I'm not sure that it is) Victorious and Hermes could launch aircraft of the same weight at the same end speed in spite of the former having shorter stroke catapults. Therefore, if Hermes could be adapted to operate Phantoms it looks like Victorious could have been too.

Rereading Hobbs, the BS4 on Victorious may have been able to use higher pressure, that might be woth something like 5 kts. Unclear whether the catapults were overhauled, so we might also compare different versions.

What is definitely odd are the two different length bs4 on Hermes giving the same end speed. The F-4 options show two Hermes cats, and the longer one has more power - something like 6-7 kts judging from the added length and the longer CAP.
View attachment 687017

By end speed do you mean 25 kt? If you do, it might be the speed the ship was steaming at, rather than the end speed.

That's a very interesting table. Do you have a link to the document that it came from?

One thing that I found curious was that that the first column is the CAP time in hours with a RB-168-25R with reheat and the second column is also the CAP time in hours with a RB-168-25R with reheat. Is the heading of the first column a typo and it's really the CAP time in hours without reheat?

But at that point the longer catapult was just a plan. Did it really get installed in the late 60s refit?

Yes it was. Photographs of Hermes that were taken after her 1964-66 refit show that the port catapult was longer than the starboard catapult,

E.g. I have my copies of Jane's 1968-69 and 1969-70 in front of me. Both editions have an aerial photograph taken in 1967 that shows this and they also have a line drawing that shows this.

 

[zen]

Is the heading of the first column a typo and it's really the CAP time in hours without reheat?

Almost certainly

 

[EwenS]

If memory serves Victorious hanger was 65.5ft wide.

Minimum Freeboard at hanger deck was ideally 24ft or above for a deck edge lift. Victorious had 14ft.
Eagle and Ark had 30ft for the upper hanger.

As originally built the Illustrious class hangars were 62ft wide (Friedman, Hobbs and Watton). Hobbs gives hangar width of the modernised Victorious as 62ft.

The drawings in Watton’s Anatomy of the ship book on Victorious have the same hangar width before and after modernisation. Having said that the table of dimensions in that book post modernisation gives 62ft 6in.

 

[bobtdwarf]

The Admiralty looked at installing a side lift on Victorious but quickly concluded that, at hangar deck level, the ship had insufficient freeboard. To have fitted one would have meant it being damaged in heavy seas and/or water entering the hangar deck itself. Not good news for any carrier due to the free surface effect.

In Ark Royal, the side lift only accessed the upper hangar. Again a lack of freeboard precluded it being extended down to access the lower hangar. It had to be removed when she was Phantomised in the 1960s when the waist catapult was fitted over the space it occupied.

The Centaur design began life with a bit more freeboard at hangar deck level allowing Hermes to have aside lift fitted in her redesign.

Trying to move the forward lift on these ships either port or starboard causes all sorts of headaches. There are solid steel walls either side that incorporate the raising/lowering chain gear and compartments outside those just under the flight deck that contain the motors to power them.

And these are “closed hangar” ships with compartments between the hangar wall and the ship’s side. The lifts themselves are more or less on the hangar centreline. So on Victorious, as reconstructed, you have a forward lift 40ft wide sitting in a hangar that is 62ft wide. That lift can only be accessed from forward and aft. So you are limited as to how far sideways you can move it without moving the hangar wall further out for a sufficient distance to take in the lift, and the space you need to manoeuvre an aircraft onto it. And remember, unlike an Essex or a Midway class, this is all structural steel work adding to the overall strength of the ship’s hull.

In Ark & Eagle the forward lift was 44ft wide in a 67ft wide hangar.

Hermes’ hangar was 62ft wide.

The Essex class were far easier to modify postwar because the main strength deck was the hangar deck, not the flight deck as in British carriers. Their hangar was superstructure, and much easier to modify. The biggest problem in them was relocating, where necessary, the various expansion joints in the hangar structure as longer catapults were fitted and lifts moved from the centreline. An Essex was an “open hanger” ship where the hangar itself, except around the island, extended the full width of the ship.

The fitting of a side of hangar lift, not deck edge is what I am referring to regarding Victorious. There is a spot you could do it but as I said I am entirely Unconvinced that it would be at all worthwhile as it would entail all the pains in the ass fitting a side lift to this design(it can be done like on the Forrestal but with more pain), while for a bonus getting you a really narrow lift because it would all remain within the hull. So it would be not so much an aircraft lift as a glorified ordinance lift with delusions of grandeur.

One of the things I remember reading about the side lift on Ark was the mechanicals for it also intruded on the lower hangar.. yeah it would be a massive PITA to do though

 

[Topi]

With all the talk of moving the forward lift of HMS Victorious to the starboard side of the hangar, I do wonder if it would have been possible to add a 199' length BS5 on the angled deck of her (and also a hypothetical modernised HMS Centaur) à la HMS Eagle and HM Ark Royal and remove one of the bow catapults altogether.

 

[orlovsky]

By end speed do you mean 25 kt? If you do, it might be the speed the ship was steaming at, rather than the end speed.

That's a very interesting table. Do you have a link to the document that it came from?

One thing that I found curious was that that the first column is the CAP time in hours with a RB-168-25R with reheat and the second column is also the CAP time in hours with a RB-168-25R with reheat. Is the heading of the first column a typo and it's really the CAP time in hours without reheat?

Hobbs gives a cat end speed of 94 kts @ 50k lbs for both. Odd, as the standard 151 ft bs5 would have 91, and the longer one should be about 97. Maybe he just took the average.

The table was posted by someone who copied it with additional info from the UK archives, just forgot where it was. I think it was about Hermes/F-4.

First column should definitely be without reheat.

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

But at that point the longer catapult was just a plan. Did it really get installed in the late 60s refit?

Yes it was. Photographs of Hermes that were taken after her 1964-66 refit show that the port catapult was longer than the starboard catapult,

E.g. I have my copies of Jane's 1968-69 and 1969-70 in front of me. Both editions have an aerial photograph taken in 1967 that shows this and they also have a line drawing that shows this.

It's another puzzle as Hobbs says nothing about the catapults in the 1964/66 refit. I have also seen a 146 ft + 103 ft combo mentioned as the initial (? edit: refit!) setup. So different lengths yes - just which ones?

Edit: Has been discussed here, the supporter of 146/103 should also be around this forum....

NavWeaps Forums-British Catapult questions.

Hello folks, some trawling of the internet on the subject of British carrier catapults has led me here with a couple of questions. Firstly, catapult s

www.tapatalk.com

 

[bobtdwarf]

With all the talk of moving the forward lift of HMS Victorious to the starboard side of the hangar, I do wonder if it would have been possible to add a 199' length BS5 on the angled deck of her (and also a hypothetical modernised HMS Centaur) à la HMS Eagle and HM Ark Royal and remove one of the bow catapults altogether.

yeah that has been discussed, totally possible just a factor of time and money. As I understand it the reason the side lift was on the port side of the Hermes was it would be the place that put the least strain on the hull

 

[zen]

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

From only the 199ft stroke catapults it would be with a useful load. From the bow 151ft stroke it's just 0.6 hours CAP with reheat on.
With Spey it's 1.3 hours.....about twice the endurance.

 

[orlovsky]

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

From only the 199ft stroke catapults it would be with a useful load. From the bow 151ft stroke it's just 0.6 hours CAP with reheat on.
With Spey it's 1.3 hours.....about twice the endurance.

That's why poor Hermes is out.

 

[datafuser]

By end speed do you mean 25 kt? If you do, it might be the speed the ship was steaming at, rather than the end speed.

That's a very interesting table. Do you have a link to the document that it came from?

One thing that I found curious was that that the first column is the CAP time in hours with a RB-168-25R with reheat and the second column is also the CAP time in hours with a RB-168-25R with reheat. Is the heading of the first column a typo and it's really the CAP time in hours without reheat?

Hobbs gives a cat end speed of 94 kts @ 50k lbs for both. Odd, as the standard 151 ft bs5 would have 91, and the longer one should be about 97. Maybe he just took the average.

The table was posted by someone who copied it with additional info from the UK archives, just forgot where it was. I think it was about Hermes/F-4.

First column should definitely be without reheat.

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

But at that point the longer catapult was just a plan. Did it really get installed in the late 60s refit?

Yes it was. Photographs of Hermes that were taken after her 1964-66 refit show that the port catapult was longer than the starboard catapult,

E.g. I have my copies of Jane's 1968-69 and 1969-70 in front of me. Both editions have an aerial photograph taken in 1967 that shows this and they also have a line drawing that shows this.

It's another puzzle as Hobbs says nothing about the catapults in the 1964/66 refit. I have also seen a 146 ft + 103 ft combo mentioned as the initial (? edit: refit!) setup. So different lengths yes - just which ones?

Edit: Has been discussed here, the supporter of 146/103 should also be around this forum....

NavWeaps Forums-British Catapult questions.

Hello folks, some trawling of the internet on the subject of British carrier catapults has led me here with a couple of questions. Firstly, catapult s

www.tapatalk.com

They must be from here.

https://www.tapatalk.com/groups/war...d-to-operate-f-4-phan-t18325-s30.html#p728199

https://www.tapatalk.com/groups/war...d-to-operate-f-4-phan-t18325-s50.html#p728588

 

[bobtdwarf]

That is some incredible information!!!! As I recall from reading the quote was "could not operate in sufficient numbers" when referring to Hermes... not sure if it was from a quote from a parliament discussion or an MoD doc..

Implies heavily that Victorious would be viable if they could swap 1-1 or near enough with Sea- Vixen; holy crap! Victorious had space for 8 SR's so there is some pad room

 

[Archibald]

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

From only the 199ft stroke catapults it would be with a useful load. From the bow 151ft stroke it's just 0.6 hours CAP with reheat on.
With Spey it's 1.3 hours.....about twice the endurance.

- Wait wait... don't forget the Clems had BS-5, sure, but cut to 171 ft. Not possible to do the "199 ft magic" you are talking about related to Victorious & Hermes, on a Clem' . My understanding is that on Clem basic hull (maxed out for Verdun and later for CdG) the catapult vs lift vs parking area is all wrong. CdG has an issue of that kind that prevents launching Rafales while landing other Rafales, can't remember exactly.

- As for Phantoms... very interesting. "Standard F-4J" did not existed back in '62 when the MN examined the Phantom option vs the Crusader one, back then must have been F-4B. Which had no flaps so much trickier at landing, on smallish Clems... yikes. No surprise they went for the Crouze.

- France had no Spey equivalent to roll into the engine bays, except if SNECMA screws Pratt for RR and JTF10 / TF306 for RB.168 Spey, probably in 1962 for the VSTOL Mirage III-V (and all that followed: F2, F3, G in that order).

- Note that Liébert & Buyck stupendous Mirage F1 books says Spey was reapetedly considered in naval-Mirages-tradeoffs in the late 1960's: it was compared to J79 and M53-2; seems all three could be swapped into the rear end of a F1.

- Unlike the larger TF306 which needed the larger F2 / F3 / G "rump" with the larger intakes, but in turn that bigger fuselage needed at least 9 tons of thrust: too heavy for an early M53-2 or a late J79, so Spey was an "in-between".

 

[bobtdwarf]

I wish I knew if the BS-5 on the Clems took advantage of the higher temp and pressure of their steam plant! If so they are probably closer to C-11s' in OOOMPH

 

[orlovsky]

Also confirms that a standard F-4J with extended nosegear would have worked from Eagle, Ark and the Clems catapult wise.

From only the 199ft stroke catapults it would be with a useful load. From the bow 151ft stroke it's just 0.6 hours CAP with reheat on.
With Spey it's 1.3 hours.....about twice the endurance.

- Wait wait... don't forget the Clems had BS-5, sure, but cut to 171 ft. Not possible to do the "199 ft magic" you are talking about related to Victorious & Hermes, on a Clem' . My understanding is that on Clem basic hull (maxed out for Verdun and later for CdG) the catapult vs lift vs parking area is all wrong. CdG has an issue of that kind that prevents launching Rafales while landing other Rafales, can't remember exactly.

- As for Phantoms... very interesting. "Standard F-4J" did not existed back in '62 when the MN examined the Phantom option vs the Crusader one, back then must have been F-4B. Which had no flaps so much trickier at landing, on smallish Clems... yikes. No surprise they went for the Crouze.

If we believe Mr Moulin, the bs5 on the clems made up for the shorter length with higher steam pressure. It would deliver eg 110 kts @ 44k lbs, just like the 199ft bs5 on Ark. As the F-4 could be launched with 56k lbs on the c-11, there should be no problem with g limits.
The F-8J required 8 kts wod on the c-11, the F-4B with the longer nose gear as basic fighter about 0.
The problem has been about arresting the beast.

 

[orlovsky]

I wish I knew if the BS-5 on the Clems took advantage of the higher temp and pressure of their steam plant! If so they are probably closer to C-11s' in OOOMPH

The nr we have, 110 kts @ 44k lbs, is a perfect fit for a shortened c-11 (169 ft instead of 205 or 211 ft).

 

[bobtdwarf]

I wish I knew if the BS-5 on the Clems took advantage of the higher temp and pressure of their steam plant! If so they are probably closer to C-11s' in OOOMPH

The nr we have, 110 kts @ 44k lbs, is a perfect fit for a shortened c-11 (169 ft instead of 205 or 211 ft).

Thanks! That is some really useful info especially for some of my AH on the super tiger

 

[orlovsky]

I wish I knew if the BS-5 on the Clems took advantage of the higher temp and pressure of their steam plant! If so they are probably closer to C-11s' in OOOMPH

The nr we have, 110 kts @ 44k lbs, is a perfect fit for a shortened c-11 (169 ft instead of 205 or 211 ft).

Thanks! That is some really useful info especially for some of my AH on the super tiger

As a rule of thumb, about 12 kts less than the c-11. Only problem may be airframe limits.

 

[Archibald]

Higher steam pressure... didn't knew about that parameter (another one, just to complicate the matter even further !).

Very interesting. In that regard the Clems may have an edge over the older British carriers with older steamplants and older technology... WWII era versus 1955, could make a difference.