Aircraft Catapults

[PMN1]

The C14 Internal Combustion Catapult is mentioned in the Alternate Naval Procurements thread

Description on the GlobalSecurity site here

Internal Combustion Catapult

www.globalsecurity.org

What if the problems associated with the IC Catapult had been fixed?

 

[SSgtC]

Small carrier projects become more viable. The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots). With an IC cat, the ship can still deliver its full flank speed, giving you a bigger range of conditions that you can launch in.

For American carriers, that was, mostly, an annoyance. Their ships were big enough, fast enough and with powerful enough catapults that it rarely mattered. The Navy still didn't like it, but they could live with it. The big thing it changes for them, is what it means for the Essex and Midway classes. With C14s in place of their C11s, there isn't a plane in the Navy's inventory that they can't launch at their full up weights. Long term, it doesn't mean that much for those two classes though since they were more limited by their hanger height combined with their limited fuel and aviation ordinance storage than they were by their catapults. They'll make launching in hot and humid conditions safer and easier, but they won't really change how the two classes are operated. Beyond giving them some more flexibility in how the Navy views them (think things like being more willing to divert a Phantom or Tomcat or Vigilante to an Essex or Midway if needed, whereas in OTL, that was only done in extremis).

It might mean the Navy invests more in nuclear escorts though. Since now, the carrier won't be slowing down during flight operations. That means more sustained speed will be needed from the various escorts. Instead of a burst to 30+ knots, they're gonna need to keep it up for a couple hours. That's a lot of extra fuel being burned.

For navies with smaller carriers, though? The C14 is a game changer. It could launch heavier aircraft at faster speeds than any British supplied catapult could even dream of. Ships like 25 de Mayo could have reliably launched Etendards and Crusaders (if Argentina had been allowed to buy them). Melbourne could have flown Crusaders and Corsairs instead of payload limited Skyhawks. Hermes could have launched Phantoms with regularity. Foch and Clem could have operated anything the French wanted them to, and then been sold on to other navies to fly aircraft like F/A-18s off of.

Longer term, it strangles the STOVL carrier in the cradle. With no need for steam to operate the catapults, and with the cats themselves being more powerful on a foot-to-foot basis than an equivalent length steam cat, smaller navies like Italy and Canada could operate smaller CATOBAR decks instead of the OTL choice of Harrier Carrier or nothing.

 

[CV12Hornet]

The decoupling from the steam plants also means you can get rid of the steam plants themselves. You could make small CATOBAR carriers with gas turbines and not have to fiddle around with some sort of steam generator, saving weight and space and crew.

Long term, it doesn't mean that much for those two classes though since they were more limited by their hanger height combined with their limited fuel and aviation ordinance storage than they were by their catapults.

The Essexes also had pretty serious limits on landing weight thanks to their lighter flight deck structures.

 

[uk 75]

For the UK a CL4 refit for Hermes would have been able to allow small numbers of Phantoms to fly from the ship.
This probably would not have saved CVA01 as her demise was as much political as budgetary.
But it would have given the 1970 Heath government an opportunity to bring back the aircraft carrier.

 

[PMN1]

That's what I was thinking about the smaller carriers.

How does the IC Catapult compare the the EM Catapult in terms of control, crew requirements etc, one thing I did notice when I did a search for IC cartapults was the amount of criticism of EM catapults.

Got to admit, had not relaied there was this category of catapult..... all I have seen is hydraulic, steam and electromagnetic.

 

[SSgtC]

That's what I was thinking about the smaller carriers.

How does the IC Catapult compare the the EM Catapult in terms of control, crew requirements etc, one thing I did notice when I did a search for IC cartapults was the amount of criticism of EM catapults.

Got to admit, had not relaied there was this category of catapult..... all I have seen is hydraulic, steam and electromagnetic.

You won't find much on it because none ever entered service. The closest they ever got was the C14, and that was only ever installed at Lakehurst.

As for comparisons between IC and EM cats, it's apples and oranges. The C14 was designed some 60 years before the EM cats of the Ford were. The precision, control, and manning requirements are completely different

 

[bobtdwarf]

I wonder how much automotive tech is applicable to this thing? Sounds a bit like a really LONG stroke engine piston with methyl water injection to a degree

 

[zen]

Actually might have altered the CVA-01 design and decisions.
Since it allows older steam plant designs to be used, cutting costs and risks.
Also relieves some of the need for Speys in the F4.

I'll need to examine the data on the C14. But it might change other things depending in the length needed.

However....
In theory....
Such a system could provide a smoother acceleration and realise a shorter system length.

 

[Anderman]

The decoupling from the steam plants also means you can get rid of the steam plants themselves. You could make small CATOBAR carriers with gas turbines and not have to fiddle around with some sort of steam generator, saving weight and space and crew.

Long term, it doesn't mean that much for those two classes though since they were more limited by their hanger height combined with their limited fuel and aviation ordinance storage than they were by their catapults.

The Essexes also had pretty serious limits on landing weight thanks to their lighter flight deck structures.

The exhaust gases of a gas turbine are hot enough to produce steam for a steam turbine like in a Steam and Gas power plant.

Combined cycle power plant - Wikipedia

en.wikipedia.org

For aircraft carriers you would need large turbines like the CF6 or the RB.211 which are around after 1970 but then the USN was moving to nuclear powered carriers and the RN was leaving the carrier business.

 

[EwenS]

Got to admit, had not relaied there was this category of catapult..... all I have seen is hydraulic, steam and electromagnetic.

Then we have also had, in Britain at least:-

The P (Projectile / Pyrotechnic) catapult - used a pack of 18x3” rockets to accelerate a trolley carrying the aircraft. Used in the British Auxiliary Fighter Catapult Ships and CAM ships of WW2

The Cordite Accelerator (catapult) - a prototype BC.I was trialled by the RAE and a BC.II (BC for British Cordite) was installed on the escort carrier Pretoria Castle. Cordite was burned to propel a cylinder in a “barrel” to which was attached, via wire ropes, the trolley carrying the aircraft.

The K (Inertia ) catapult - using a large flywheel to store the energy. Again trialled by the RAE during WW2.

Post-war the USN developed the C 10 catapult for use in the SCB-27C Essex class conversions. This was a powder type (similar in concept to the British cordite accelerator) with the breech end near the bow. The ship would have needed 50 tons of catapult charges (90 tons in early plans) which caused problems in an otherwise volume constrained hull.

Then Britain rode to the rescue of the USN with the invention of the steam catapult.

The Germans also used a catapult system to launch the V1 flying bombs. This used hydrogen peroxide (T Stoff) and sodium permanganate (Z Stoff) to generate steam to feed into the catapult.

 

[Archibald]

The thread title is not very clear, could you change it ?

Internal Combustion Catapult

www.globalsecurity.org

The post below completely blew my mind. Never realized all this.

Small carrier projects become more viable. The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots). With an IC cat, the ship can still deliver its full flank speed, giving you a bigger range of conditions that you can launch in.

For American carriers, that was, mostly, an annoyance. Their ships were big enough, fast enough and with powerful enough catapults that it rarely mattered. The Navy still didn't like it, but they could live with it. The big thing it changes for them, is what it means for the Essex and Midway classes. With C14s in place of their C11s, there isn't a plane in the Navy's inventory that they can't launch at their full up weights. Long term, it doesn't mean that much for those two classes though since they were more limited by their hanger height combined with their limited fuel and aviation ordinance storage than they were by their catapults. They'll make launching in hot and humid conditions safer and easier, but they won't really change how the two classes are operated. Beyond giving them some more flexibility in how the Navy views them (think things like being more willing to divert a Phantom or Tomcat or Vigilante to an Essex or Midway if needed, whereas in OTL, that was only done in extremis).

It might mean the Navy invests more in nuclear escorts though. Since now, the carrier won't be slowing down during flight operations. That means more sustained speed will be needed from the various escorts. Instead of a burst to 30+ knots, they're gonna need to keep it up for a couple hours. That's a lot of extra fuel being burned.

For navies with smaller carriers, though? The C14 is a game changer. It could launch heavier aircraft at faster speeds than any British supplied catapult could even dream of. Ships like 25 de Mayo could have reliably launched Etendards and Crusaders (if Argentina had been allowed to buy them). Melbourne could have flown Crusaders and Corsairs instead of payload limited Skyhawks. Hermes could have launched Phantoms with regularity. Foch and Clem could have operated anything the French wanted them to, and then been sold on to other navies to fly aircraft like F/A-18s off of.

Longer term, it strangles the STOVL carrier in the cradle. With no need for steam to operate the catapults, and with the cats themselves being more powerful on a foot-to-foot basis than an equivalent length steam cat, smaller navies like Italy and Canada could operate smaller CATOBAR decks instead of the OTL choice of Harrier Carrier or nothing.

Be still my heart ! I've been toying with similar ideas since 2006, except I didn't knew about the C14. The above tells me it is the piece I was missing to make it happens. Only took the best part of two decades for me to learn about that thing. D'OOOOOH !!!

You listed all the carriers that would benefit from it - Hermes, Colossus & Majestics, Clems. Victorious and Saipans could be added.

Maybe even the surviving Independances - Dedalo for Spain, Lafayette & Bois Belleau for France.

Independence-class aircraft carrier - Wikipedia

en.wikipedia.org

So how about finishing the two WWII crippled Essex - Franklin and Bunker Hill - with C14 catapults ? now THAT would be something to behold. Sell that to the RN or RAAN.

Also Zumwalt - as you said, SCS would be nipped in the budd - the real deal would be VSS (30 000 tons) and CVV (60 000 tons + from memory).

 

[SSgtC]

Be still my heart ! I've been toying with similar ideas since 2006, except I didn't knew about the C14. The above tells me it is the piece I was missing to make it happens. Only took the best part of two decades for me to learn about that thing. D'OOOOOH !!!

You listed all the carriers that would benefit from it - Hermes, Colossus & Majestics, Clems. Victorious and Saipans could be added.

Maybe even the surviving Independances - Dedalo for Spain, Lafayette & Bois Belleau for France.

Independence-class aircraft carrier - Wikipedia

en.wikipedia.org

So how about finishing the two WWII crippled Essex - Franklin and Bunker Hill - with C14 catapults ? now THAT would be something to behold. Sell that to the RN or RAAN.

Also Zumwalt - as you said, SCS would be nipped in the budd - the real deal would be VSS (30 000 tons) and CVV (60 000 tons + from memory).

It's possible that those ships could have them installed. There's other issues that would probably preclude it (size of the ship, fuel and ammunition stowage, age, etc), but it is doable if they want. The great thing about the C14 is that it was designed to be installed in any existing steam catapult.

 

[PMN1]

The thread title is not very clear, could you change it ?

Would rather keep it the same as want to bring in other catapult types if there is information.

 

[BlackBat242]

Got to admit, had not relaied there was this category of catapult..... all I have seen is hydraulic, steam and electromagnetic.

Then we have also had, in Britain at least:-

The P (Projectile / Pyrotechnic) catapult - used a pack of 18x3” rockets to accelerate a trolley carrying the aircraft. Used in the British Auxiliary Fighter Catapult Ships and CAM ships of WW2

The Cordite Accelerator (catapult) - a prototype BC.I was trialled by the RAE and a BC.II (BC for British Cordite) was installed on the escort carrier Pretoria Castle. Cordite was burned to propel a cylinder in a “barrel” to which was attached, via wire ropes, the trolley carrying the aircraft.

The K (Inertia ) catapult - using a large flywheel to store the energy. Again trialled by the RAE during WW2.

Post-war the USN developed the C 10 catapult for use in the SCB-27C Essex class conversions. This was a powder type (similar in concept to the British cordite accelerator) with the breech end near the bow. The ship would have needed 50 tons of catapult charges (90 tons in early plans) which caused problems in an otherwise volume constrained hull.

Then Britain rode to the rescue of the USN with the invention of the steam catapult.

The Germans also used a catapult system to launch the V1 flying bombs. This used hydrogen peroxide (T Stoff) and sodium permanganate (Z Stoff) to generate steam to feed into the catapult.

F MK II (10,000 lb to 35 mph) flywheel type aboard CV-2 & CV-3 in 1928 to ~1937

 

[BlackBat242]

So how about finishing the two WWII crippled Essex - Franklin and Bunker Hill - with C14 catapults ? now THAT would be something to behold. Sell that to the RN or RAAN.

Both had already been fully repaired.

Bunker Hill CV-17 was badly damaged on 11 May 1945, and anchored in Puget Sound Navy Yard (WA) on 3 June 1945. She was in drydock from 4 June - 22 July, then continued repair work alongside Pier #3, sailing out on 27 September 1945 - being rated "fully ready for service in all respects". She was in Alameda, CA by 30 Sept, and departed for Hawaii 3 Oct. She then proceeded to first Guam, then the Philippines to ferry home veterans of the Pacific War. She decommissioned January 1947.

Franklin CV-13 was badly damaged on 19 March 1945, and anchored in New York Nave Yard (NY) on 30 April 1945. By 13 October 1945 her repairs were complete enough to allow thousands of civilian visitors aboard for Navy Day. She finally completed all repairs on 15 June 1946, and immediately joined many of her sisters in the Reserve Fleet, formally decommissioning in February 1947.

By the end of 1947 16 Essex class carriers were decommissioned and in the reserve fleet, with only 8 (and the 3 Midway class large carriers) in the active fleet (along with a few CVLs & CVEs as ASW carriers).

By the beginning of 1950 this was down to 4 Essex & 3 Midway CVs in active service (along with 4 CVLs & 4 CVEs as ASW carriers).

https://www.history.navy.mil/research/histories/ship-histories/us-ship-force-levels.html#1945

 

[Archibald]

I know this. Mostly interested in their long term fate. They stood in reserve for 20 years or more (1945-1965), waiting for a post - SBC-125A rebuild that never came. Hence my suggestion to finish them with C14 catapults.

 

[uk 75]

I think that even if C14 is successful the USN will still puts its resources into the Forrestal and Nimitz classes.
These platforms offer a large and varied airgroup able to carry out ASW, area air defence and strike missions while being at the centre of layered defences.
Size will always matter for aircraft carriers.
The impact on smaller nations' navies, however, will be considerable if heavier aircraft can be launched ( but also recovered and operated)..
An improved gas turbine powered Hermes size carrier with one ASW hello one F4 and one Buccaneer squadron would become feasible.
But as the RN has shown with its two current carriers size is still important.
CVA01 might still be unaffordable in the 1960s as I have mentioned elsewhere because we needed Polaris and SSN more.
I for one would happily have traded CVF for a decent number of Astutes.

 

[Archibald]

In an ideal world (with C-14 catapults)
- RN put C14s on the four Centaurs and brought all of them to Hermes standard (if that's even remotely feasible)
- France gets C14s for the Clems
- Bunker Hill and Franklin found their way to the RAAN

 

[uk 75]

The problem for the RN is that at least two of the Centaurs are needed as Commando Ships. The older carriers were too old and small and a new design would take too long.
So Bulwark and Albion are off the list.
Centaur and Hermes remain.
I am assuming that with C14 fitted both ships could operate at least a mixture of Buccaneer S2 and Sea Vixen FAW2.
This leaves room for Eagle to be converted instead of Ark Royal.
Victorious seems to be dubious on age grounds and Ark will be needed for parts for Eagle.
So Phantoms enter service on Eagle in 1969 instead of 1970 on Ark.
Hermes is refitted to operate some F4s in 1968 and re-enters service in 1971.
CVA01 is still cancelled in 1966 for budgetary reasons.
In 1970 the Heath Conservative government is faced with a choice between 3 to 6 ASW Command Cruisers and two CVA to replace Eagle and Hermes from 1980.

 

[EwenS]

I can't find anywhere any details of the length of the C-14. Given that it was replaced by the C13 on the Enterprise that suggests a length around 250 feet.

Now if it needs to be shortened for the British carriers, what does that do its launch power (weight and end speed?) without damaging the aircraft?

 

[bobtdwarf]

I think that even if C14 is successful the USN will still puts its resources into the Forrestal and Nimitz classes.
These platforms offer a large and varied airgroup able to carry out ASW, area air defence and strike missions while being at the centre of layered defences.
Size will always matter for aircraft carriers.
The impact on smaller nations' navies, however, will be considerable if heavier aircraft can be launched ( but also recovered and operated)..
An improved gas turbine powered Hermes size carrier with one ASW hello one F4 and one Buccaneer squadron would become feasible.
But as the RN has shown with its two current carriers size is still important.
CVA01 might still be unaffordable in the 1960s as I have mentioned elsewhere because we needed Polaris and SSN more.
I for one would happily have traded CVF for a decent number of Astutes.

Generally concur, but will point out that every now and again the USN does a small batch experiment build to fully understand or workout the details of a new technology etc. If they were going to do one of those these would be the best candidates since at the very worst you could use them as a replacement training carrier.

 

[uk 75]

A CVS for the 1970s would certainly have used C14 for the S3 Viking and could then have carried a flight of F14 for sellf protection pethaps detached from the CVAN.

 

[bobtdwarf]

A CVS for the 1970s would certainly have used C14 for the S3 Viking and could then have carried a flight of F14 for sellf protection pethaps detached from the CVAN.

Doable, and just a wild thought, put one on the East coast and one on the West and use them for naval reserve training

 

[Lascaris]

Ok I can see the advantages of having a working IC catapult... like everyone else I suppose. For the obvious question what it takes to get C14 working though? Is it just a matter of development time/improving reliability?

As someone who's been doing systems integration, among other things, for a living the complaints in the link here http://www.bobholland.com/me/reaction3.htm sound to be classic developer refusing to accept the end users are idiots and you need to idiot proof your system, the navy testers needless to say were doing the right thing throwing every possible wrench in the machine. But if these are the ONLY problems there were then they were probably fixable. The mention on an uneven end speed seems more problematic if it was not directly connected to these.

Second obvious question, if the IC catapult is offering obvious advantages for smaller carriers how practical it would be for the British to develop a design independently in the late 1950s /as part of CVA development?

 

[Hood]

Lascaris has for me hit on the $64 million question. Would the IC catapult ever work reliably enough and what would it take to make it work? Statements like "no Vietnam = loadsa dosh = working catapult" seem a bit simplistic to me.

It obviously did work to an extent but not reliably - and interestingly nobody else who was in the carrier game seems to come up with one (you might think the Soviets would have attempted).

 

[Archibald]

More on the C-14: Naval Aviation News, 1958.

Naval Aviation News

www.google.fr

I learned a detail about it that blew my mind. Guess which company got the contract ? Reaction Motors Inc.

Reaction Motors - Wikipedia

en.wikipedia.org

In a few words: the rocket company that build the X-1 and X-15 engines, among others. The XLR-11 & XLR-99.

So it was more akin to a rocket catapult than an IC one.

RMI was one very interesting company, a bit like Marquardt for ramjets.

https://www.hydrogen-peroxide.us/history-US-Reaction-Motors/AIAA-2001-3838_History_of_RMI_Super_Performance_90_Percent_H2O2-Kerosene_LR-40_RE-pitch.pdf

 

[Archibald]

A CVS for the 1970s

What do you mean by "CVS" ? one of the older, unmodified Essex carriers ?

Might be fun if a reborn C-14 allowed a few Essex (the ones in best shape: the two crippled in reserve plus Oriskany, Hancock, Lexington) to last longer in service by handling heavier aircraft more easily - thinking about Hornets to replace their rebuild Crusaders. As said upthread however others limits would remain (ammunition and fuel storage).

 

[bobtdwarf]

Lascaris has for me hit on the $64 million question. Would the IC catapult ever work reliably enough and what would it take to make it work? Statements like "no Vietnam = loadsa dosh = working catapult" seem a bit simplistic to me.

It obviously did work to an extent but not reliably - and interestingly nobody else who was in the carrier game seems to come up with one (you might think the Soviets would have attempted).

one would think that if they could even get to a consistent drop off level at a given length they could add a little "booster" chamber at a point to goose it along and tighten up the end speed.

A consistent drop off could be worked with I would think: Plan your launches for the lowest velocity and if you get the higher one it is a nice bonus.

 

[isayyo2]

What do you mean by "CVS" ? one of the older, unmodified Essex carriers ?

Maybe SCB 101.68 or 101.71?

https://www.secretprojects.co.uk/threads/the-fy53-fy68-asw-carriers.31070/#post-339898

 

[H_K]

The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots).

Coming back to this… any source for these numbers? They seem an order of magnitude too high… the rare numbers I’ve heard of mention a speed reduction of maybe 1-2 knots, significantly less than the 8-12 knots above.

 

[red admiral]

Aren't they basically liquid propellant guns that are really long? I'm pretty sure that consistency will be the main issue. Any ideas on peak load to average load ratio to compare to the likes of EMALS or steam cats?

 

[SSgtC]

The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots).

Coming back to this… any source for these numbers? They seem an order of magnitude too high… the rare numbers I’ve heard of mention a speed reduction of maybe 1-2 knots, significantly less than the 8-12 knots above.

I'll have to look it up. The major drop off for the Essex and Midway classes is due to steam cats being a refit item, not something they were originally planned to have, so they just didn't have the excess steam capacity to operate them without suffering a fairly significant drop in speed. The nuclear carriers, that was based on word of mouth, since the actual number is classified.

Ok I can see the advantages of having a working IC catapult... like everyone else I suppose. For the obvious question what it takes to get C14 working though? Is it just a matter of development time/improving reliability?

As someone who's been doing systems integration, among other things, for a living the complaints in the link here http://www.bobholland.com/me/reaction3.htm sound to be classic developer refusing to accept the end users are idiots and you need to idiot proof your system, the navy testers needless to say were doing the right thing throwing every possible wrench in the machine. But if these are the ONLY problems there were then they were probably fixable. The mention on an uneven end speed seems more problematic if it was not directly connected to these.

Second obvious question, if the IC catapult is offering obvious advantages for smaller carriers how practical it would be for the British to develop a design independently in the late 1950s /as part of CVA development?

AIUI, the Navy was using a servo-mechanical system to open and close valves in the pipe to regulate the pressure in the launch tube. But the system couldn't react fast enough. So you'd have times where valves were open when they should have been closed and closed when they should have been open. This ended up giving you shuttle end run speeds all over the map with identical loads on them. I think it's fixable. Instead of using sensors in the pipe to control it, use a computer (even late 50s/early 60s ones were good enough for this) to put in launch weight, temperature and humidity and use it to give you a set time and order to open and close the valves. It's a little more cumbersome, but I think it's reliability would shoot up doing that

 

[bobtdwarf]

The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots).

Coming back to this… any source for these numbers? They seem an order of magnitude too high… the rare numbers I’ve heard of mention a speed reduction of maybe 1-2 knots, significantly less than the 8-12 knots above.

I'll have to look it up. The major drop off for the Essex and Midway classes is due to steam cats being a refit item, not something they were originally planned to have, so they just didn't have the excess steam capacity to operate them without suffering a fairly significant drop in speed. The nuclear carriers, that was based on word of mouth, since the actual number is classified.

Ok I can see the advantages of having a working IC catapult... like everyone else I suppose. For the obvious question what it takes to get C14 working though? Is it just a matter of development time/improving reliability?

As someone who's been doing systems integration, among other things, for a living the complaints in the link here http://www.bobholland.com/me/reaction3.htm sound to be classic developer refusing to accept the end users are idiots and you need to idiot proof your system, the navy testers needless to say were doing the right thing throwing every possible wrench in the machine. But if these are the ONLY problems there were then they were probably fixable. The mention on an uneven end speed seems more problematic if it was not directly connected to these.

Second obvious question, if the IC catapult is offering obvious advantages for smaller carriers how practical it would be for the British to develop a design independently in the late 1950s /as part of CVA development?

AIUI, the Navy was using a servo-mechanical system to open and close valves in the pipe to regulate the pressure in the launch tube. But the system couldn't react fast enough. So you'd have times where valves were open when they should have been closed and closed when they should have been open. This ended up giving you shuttle end run speeds all over the map with identical loads on them. I think it's fixable. Instead of using sensors in the pipe to control it, use a computer (even late 50s/early 60s ones were good enough for this) to put in launch weight, temperature and humidity and use it to give you a set time and order to open and close the valves. It's a little more cumbersome, but I think it's reliability would shoot up doing that

This may sound odd but... This sounds like a variable valve timing/electronic fuel injection issue.. to use automotive analog. If so then this is TOTALLY solvable by at least 1974 using a Bosch K-jetronic electronic fuel injection computer and sensors as a guide: It would adjust fuel load (could be tweak to adjust valve open/close instead) based on temp/humidity on my brothers Euro spec Opel.. or the Saab Lambda system.

So yeah totally solvable issue to my mind.

 

[zen]

The Germans managed staged acceleration in their 'supergun' and I dimly reccal the UK took that.

And oddly I'd expect the RN to be willing to fund a computer controlled version. Possibly using solenoids.

That could lead to sharing/collaboration with the USN.

 

[Lascaris]

The issue with steam cats has always been the need to divert steam from propulsion to the cats to launch aircraft. This slows the ship down. In the Essex class, they would drop from 31 knots all the way down to 19 knots during flight operations. The Midway class would drop from 31-32 knots down to 23. Even the Nimitz class loses speed during flight operations (the exact amount is classified, but it's believed to be down into the neighborhood of 25 knots).

Coming back to this… any source for these numbers? They seem an order of magnitude too high… the rare numbers I’ve heard of mention a speed reduction of maybe 1-2 knots, significantly less than the 8-12 knots above.

I'll have to look it up. The major drop off for the Essex and Midway classes is due to steam cats being a refit item, not something they were originally planned to have, so they just didn't have the excess steam capacity to operate them without suffering a fairly significant drop in speed. The nuclear carriers, that was based on word of mouth, since the actual number is classified.

Ok I can see the advantages of having a working IC catapult... like everyone else I suppose. For the obvious question what it takes to get C14 working though? Is it just a matter of development time/improving reliability?

As someone who's been doing systems integration, among other things, for a living the complaints in the link here http://www.bobholland.com/me/reaction3.htm sound to be classic developer refusing to accept the end users are idiots and you need to idiot proof your system, the navy testers needless to say were doing the right thing throwing every possible wrench in the machine. But if these are the ONLY problems there were then they were probably fixable. The mention on an uneven end speed seems more problematic if it was not directly connected to these.

Second obvious question, if the IC catapult is offering obvious advantages for smaller carriers how practical it would be for the British to develop a design independently in the late 1950s /as part of CVA development?

AIUI, the Navy was using a servo-mechanical system to open and close valves in the pipe to regulate the pressure in the launch tube. But the system couldn't react fast enough. So you'd have times where valves were open when they should have been closed and closed when they should have been open. This ended up giving you shuttle end run speeds all over the map with identical loads on them. I think it's fixable. Instead of using sensors in the pipe to control it, use a computer (even late 50s/early 60s ones were good enough for this) to put in launch weight, temperature and humidity and use it to give you a set time and order to open and close the valves. It's a little more cumbersome, but I think it's reliability would shoot up doing that

This may sound odd but... This sounds like a variable valve timing/electronic fuel injection issue.. to use automotive analog. If so then this is TOTALLY solvable by at least 1974 using a Bosch K-jetronic electronic fuel injection computer and sensors as a guide: It would adjust fuel load (could be tweak to adjust valve open/close instead) based on temp/humidity on my brothers Euro spec Opel.. or the Saab Lambda system.

So yeah totally solvable issue to my mind.

Hmm. Looks a relatively straightforward automated control systems problem. So for what's worth I'm sold on the technical feasibility, if someone was to make one today, it was apparently proposed as an alternative/backup to EMALS, Clint Stallard from which most of the presentations online for IC catapults seem to come was apparently program director on that one and vehemently supporting the feasibility including this interesting tidbit here for the original design, which you can take with as much a grain of salt as you care to:




So if technically feasible which the thing seems to be, the question becomes how early can you reliably do it. The comparison with electronic fuel injection computers is not a bad one I think. Thus no later than 1974 seems a logical assumption. How much earlier than 1974? 5 to 10 years from the original 1958 testing seems... not unreasonable? Which means in time either for USS America or JFK.

 

[bobtdwarf]

it would be worth doing just for the retrofit capability on the older Nimitiz class ships and CdG.
I give a lot of credence to a senior program engineer and the tidbit of constructing four sets says to me at least that the USN considered them as reliable as a steam cat... remember the first 3 CVA-19 steam cats were built by the Brits.. so 4 sets implies going for them at least as hard as for steam initially.

 

[Lascaris]

Is there a point in putting an ICCALS on a Wasp removing the need to operate only STOVL aircraft in the sea control role? Or it would affect too much the ship in the amphibious role/increase cost too much? The USN may not care but say Australia would certainly do if she could have HMAS Canberra as a light carrier with CATOBAR capability...

 

[SSgtC]

Is there a point in putting an ICCALS on a Wasp removing the need to operate only STOVL aircraft in the sea control role? Or it would affect too much the ship in the amphibious role/increase cost too much? The USN may not care but say Australia would certainly do if she could have HMAS Canberra as a light carrier with CATOBAR capability...

It would be doable, but then you run into the whole issue of why angled decks were invented in the first place. Plus the Wasp class are really badly designed to serve as full time carriers. They have very small hangers and extremely restrictive fuel and aviation ordinance storage. Bringing them up to full carrier capability (for their size) would entail such a massive redesign that you might as well design a purpose built carrier from the keel up.

Installing one just to let you launch other aircraft types doesn't really work either. Even a C14 needs dedicated maintainers and operators for what would be a very, very small percentage of operations. And unless you're adding an angled deck and arresting gear, your essentially building a CAM ship: able to launch aircraft, but can't recover them. It's a one shot trick. Once the planes are airborne, you've shot your bolt

 

[Lascaris]

Is there a point in putting an ICCALS on a Wasp removing the need to operate only STOVL aircraft in the sea control role? Or it would affect too much the ship in the amphibious role/increase cost too much? The USN may not care but say Australia would certainly do if she could have HMAS Canberra as a light carrier with CATOBAR capability...

It would be doable, but then you run into the whole issue of why angled decks were invented in the first place. Plus the Wasp class are really badly designed to serve as full time carriers. They have very small hangers and extremely restrictive fuel and aviation ordinance storage. Bringing them up to full carrier capability (for their size) would entail such a massive redesign that you might as well design a purpose built carrier from the keel up.

Installing one just to let you launch other aircraft types doesn't really work either. Even a C14 needs dedicated maintainers and operators for what would be a very, very small percentage of operations. And unless you're adding an angled deck and arresting gear, your essentially building a CAM ship: able to launch aircraft, but can't recover them. It's a one shot trick. Once the planes are airborne, you've shot your bolt

This makes sense of course. In that case though you still have around the primary customer for STOVL aircraft namely the US Marine Corps.

 

[zen]

So if technically feasible which the thing seems to be, the question becomes how early can you reliably do it. The comparison with electronic fuel injection computers is not a bad one I think. Thus no later than 1974 seems a logical assumption. How much earlier than 1974? 5 to 10 years from the original 1958 testing seems... not unreasonable? Which means in time either for USS America or JFK.

I would say earlier.
As this is more a staggered linear system, similar to the supergun technology.
Potentially doable with a repurposed Elliot's MRS5 computer. Albeit that's 5 tons of valve based programmable computer developed for gunnery. So 1958-65.
An analogue system could be achieved, more compact and faster but would use swappable components for each plane's characteristics....
The latter is more likely a UK effort from the 50's.