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Post by steel selachian on Jan 10, 2015 12:16:09 GMT -6
I think the ski ramps and catapults combo is something you might see under a certain design philosophy; the Russians for example tended to be hung up on redundancy. The Kirovs had a nuke plant AND oil-fired boilers, their carriers had aircraft and heavy AShMs, and they would slap multiple redundant defensive weapons systems on their ships. The logic behind a ski jump bow with waist catapults might be to ensure that if the catapults crap out (or if they just plain don't work from the get-go) the ship is still capable of launching aircraft. It's also easier for pilots to transition to ops on such a ship from the current CV-16 deck layout. The USN viewpoint on the other hand would probably argue that they should have just started with a flush deck and catapults.
Whether the PLAN has the same thought as the Russians is unknown, although the fact that they still put Russian-pattern ASW rocket launchers on their ships says they might.
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Post by oldpop2000 on Jan 11, 2015 9:06:11 GMT -6
I think the ski ramps and catapults combo is something you might see under a certain design philosophy; the Russians for example tended to be hung up on redundancy. The Kirovs had a nuke plant AND oil-fired boilers, their carriers had aircraft and heavy AShMs, and they would slap multiple redundant defensive weapons systems on their ships. The logic behind a ski jump bow with waist catapults might be to ensure that if the catapults crap out (or if they just plain don't work from the get-go) the ship is still capable of launching aircraft. It's also easier for pilots to transition to ops on such a ship from the current CV-16 deck layout. The USN viewpoint on the other hand would probably argue that they should have just started with a flush deck and catapults. Whether the PLAN has the same thought as the Russians is unknown, although the fact that they still put Russian-pattern ASW rocket launchers on their ships says they might. One of the real issues that is not offered or discussed is operational experience. The Chinese and the Russians have none with regards to carriers operations. The US has more operational experience than any other nation in the area of carriers. We know what will work and what will not work. Catapults, while more complicated, can reduce air wing launch times dramatically and in many situations, that is vital . Ski ramps can only launch under near perfect sea conditions, something you and I know doesn't exist in the ocean. Fully loaded aircraft cannot take off from the bow ramps and there are usually only two. Fully loaded birds need a ramp that takes most of the flight deck. Aircraft using ski ramps must use full AB which reduces engine life and increases fuel consumption. The Chinese will have to develop carrier borne fuel tankers to offset that extra fuel usage or develop external fuel tanks like the 450 gallon tanks we use. This also increases wing loads and hence, reduces ordnance loads. Something else to consider is that with ski jumps, you will loose deck space for helo's and you cannot launch and recover aircraft at the same time. If the Chinese are aware of these limitations and still pursue ski ramps, the only conclusion is that; they intend to use the carriers for fleet protection only and not as sea and land attack platforms or that they do not intend to confront US carriers. I don't feel a hybrid, using both is really workable. They will find that out and possibly on the next carrier class, use strictly catapults. However, they will have to move to nuclear propulsion to use them, as the catapults require either lots of steam pressure and the system to accompany it or they will have to develop electromagnetic as we have done.
All this brings us back to the idea that doctrine and geostrategy determine requirements and that generates specifications.
BTW, steam catapults generate about 1530 lbs. of steam for each launch, which is piped from the reactors. This sudden application of pressure on an airframe is life does reduce the life of the aircraft and does require frequent magna-fluxing of the whole aircraft especially the fuselage to detect microscopic cracks. The electromagnetic rail system applies pressure more gradually in an acceleration mode, thereby reducing that problem. This is very important for the length of service for aircraft. Most birds are scrapped due to airframe problems. Engines and electronics can be upgraded easily, but not airframes.
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Post by steel selachian on Jan 11, 2015 19:48:28 GMT -6
Is nuclear propulsion really necessary for steam cats? We had them on the older oil-burning carriers (even the SCB-27C Essex-class conversions). Granted aircraft weights keep going up, but the Forrestals and Kitty Hawks could fling a fully loaded F-14 (or even the abortive F-111B) off the deck. The PLAN could probably build something the size of the Liaoning with steam or EMALS cats that could launch a loaded J-15. However, the cats themselves are an issue - we're really the only ones who have built carrier steam catapults for a long while; the French even bought C-13 catapults from the US for the Charles de Gaulle. I think the last time anyone put a non-US steam catapult on a carrier was either with the French Clemenceau-class ships in the early 1960s or when HMS Eagle was refitted around the same time. They'd basically have to work something out from scratch or run some industrial espionage, the latter course of which can be hit-or-miss.
As far as carrying external tanks or using buddy tankers, you hit the same problem - you have to light-load the aircraft in order for it to use the ski-jump. I seem to recall hearing somewhere that while the Su-33 could be configured as a buddy tanker, in that configuration it would be too heavy to get off the deck. The reports I've heard of the J-15's maximum loadout for ski-jump takeoffs leave me thinking that external tanks or buddy pods are strictly out of the question.
In regards to doctrine and geostrategy defining requirements, that was one supposition I read recently regarding the PLAN's new Type 052C/D DDGs - they may be employed more as a sort of outer air defense perimeter for the Chinese mainland than as power-projection escorts.
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Post by oldpop2000 on Jan 11, 2015 20:21:53 GMT -6
Is nuclear propulsion really necessary for steam cats? We had them on the older oil-burning carriers (even the SCB-27C Essex-class conversions). Granted aircraft weights keep going up, but the Forrestals and Kitty Hawks could fling a fully loaded F-14 (or even the abortive F-111B) off the deck. The PLAN could probably build something the size of the Liaoning with steam or EMALS cats that could launch a loaded J-15. However, the cats themselves are an issue - we're really the only ones who have built carrier steam catapults for a long while; the French even bought C-13 catapults from the US for the Charles de Gaulle. I think the last time anyone put a non-US steam catapult on a carrier was either with the French Clemenceau-class ships in the early 1960s or when HMS Eagle was refitted around the same time. They'd basically have to work something out from scratch or run some industrial espionage, the latter course of which can be hit-or-miss. As far as carrying external tanks or using buddy tankers, you hit the same problem - you have to light-load the aircraft in order for it to use the ski-jump. I seem to recall hearing somewhere that while the Su-33 could be configured as a buddy tanker, in that configuration it would be too heavy to get off the deck. The reports I've heard of the J-15's maximum loadout for ski-jump takeoffs leave me thinking that external tanks or buddy pods are strictly out of the question. In regards to doctrine and geostrategy defining requirements, that was one supposition I read recently regarding the PLAN's new Type 052C/D DDGs - they may be employed more as a sort of outer air defense perimeter for the Chinese mainland than as power-projection escorts. Well, an F-14A had a weight of about 42,000 lbs. The F-18E/F has a weight of 66,000 lbs. Catapults had to be stronger and faster, and that means more steam. Easiest method was to pipe steam from a nuclear power plant, which is already making plenty of steam.
The buddy tanker system probably won't work with a ski jump system, just my opinion. I think the facts probably show that.
As to the PLAN doctrine etc. I don't think it is power projection as much as it is command of the seas for commercial purposes.
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Post by steel selachian on Jan 11, 2015 23:31:23 GMT -6
You're referring to the empty weight for the F-14A versus fully loaded for the F/A-18E/F. Empty weight on the Super Hornet is only 32,000 lbs. The max takeoff weight for the Tomcat was over 74,000 lbs; for the F-111B 88,000 lbs. The F-111B did carrier trials on the Coral Sea; even if it was only carrying minimal fuel the empty weight of that airframe was 49,000 pounds (79,000 lbs "loaded"). The F-14 operated off of the Forrestals and Kitty Hawks without issue throughout its career; it was not cleared to operate from the Midway-class ships.
Assuming the J-15 is close to spec with the Su-33, its empty weight is around 40,000 lbs and max takeoff weight is about 66,000 lbs. If the PLAN goes the steam catapult route, they will not need a nuclear plant.
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Post by oldpop2000 on Jan 12, 2015 11:06:43 GMT -6
You're referring to the empty weight for the F-14A versus fully loaded for the F/A-18E/F. Empty weight on the Super Hornet is only 32,000 lbs. The max takeoff weight for the Tomcat was over 74,000 lbs; for the F-111B 88,000 lbs. The F-111B did carrier trials on the Coral Sea; even if it was only carrying minimal fuel the empty weight of that airframe was 49,000 pounds (79,000 lbs "loaded"). The F-14 operated off of the Forrestals and Kitty Hawks without issue throughout its career; it was not cleared to operate from the Midway-class ships. Assuming the J-15 is close to spec with the Su-33, its empty weight is around 40,000 lbs and max takeoff weight is about 66,000 lbs. If the PLAN goes the steam catapult route, they will not need a nuclear plant. I wasn't being totally specific, the F14A normally didn't carry AIM-54C Phoenix missiles which way over 1000 lbs. plus two 267 gal drop tanks inboard. The AIM-9s weighed about 195 lbs. depending on the version. The AIM-7s weighed about 510 lbs. The AIM-120s weigh about 335 lbs. In the normal air to air mode she would carry four AIM-9s and four AIM-7s, but she could carry one or two AIM-54s. She would carry two fuel tanks on the fuselage. Those tanks were normally 267 gallons. Her jet fuel weighed 6.8 lbs per gallon, so her total external fuel weighed 3,631.2 lbs., AIM-9s weighed about 800 lbs. total, AIM-7s weighed about 2000 lbs. Total weight was then 42,000 lbs. plus 6431 lbs. or at least 48,000 lbs. not counting internal fuel, oxygen etc. She carried 2400 gallons of fuel internally, which translate to 16320 lbs. Now, total weight is about 64000 lbs. This is the standard F-14A air to air mode. You can use those figures and others, to develop the F-18 series loadouts and total combat weight.
As to the issue of conventional versus nuclear power. Our last conventional carrier was the JFK launched in 1968. Both the America and JFK were actually originally designed as austere nukes but that was changed. From that point on, its been nukes. They are heavier, but will generate more steam. Wish the Commander would get on here and educate both of us about this issue. He knows it. Now, could the PLAN develop a conventionally powered steam turbine driven carrier and use catapults? Absolutely, if they wanted to increase the complexity of the steam system use to drive the cats, but they are probably not going to do that. They will use their heads and adopt nukes. Fuel is hard for them to get, so it makes good sense to eliminate that from the needs of their navy.
www.realcleardefense.com/articles/2014/04/16/the_real_reason_china_wants_aircraft_carriers.html - Is this the real reason? How does it affect our discussion?
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Post by oldpop2000 on Jan 13, 2015 9:00:42 GMT -6
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Post by oldpop2000 on Jan 13, 2015 15:58:27 GMT -6
Just a reminder about carrier development. It takes time, experience and endless hours of research, experimentation and accidents to finally develop the technology and doctrine for carrier aviation. The British had the HMS Argus, we had the Langley and the Japanese had the Hosho. This is where the Chinese are now, they have a carrier of dubious quality, land based aircraft adapted to fly from carriers and helicopters. It's a start but let's remember the learning curve and the fact that they might change direction many times until technology and doctrine merge.
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Post by steel selachian on Jan 13, 2015 18:03:55 GMT -6
I love how that first article suggests equipping the J-15 with the BrahMos AShM as a counter to its short reach. What a joke. The BrahMos is a pig of a weapon - 2,500 kg or over 5,000 lbs. Good luck getting off the ski-jump with that thing, internal fuel, and a couple of self-defense AAMs. And with a max range of 290 km, you're still on the shorter end of the stick against US carrier aircraft armed with LRASM. I'm agreeing with the idea that until they get a flush-deck CV with catapults their naval aviation is primarily going to be for fleet air defense only.
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Post by oldpop2000 on Jan 13, 2015 18:47:51 GMT -6
I love how that first article suggests equipping the J-15 with the BrahMos AShM as a counter to its short reach. What a joke. The BrahMos is a pig of a weapon - 2,500 kg or over 5,000 lbs. Good luck getting off the ski-jump with that thing, internal fuel, and a couple of self-defense AAMs. And with a max range of 290 km, you're still on the shorter end of the stick against US carrier aircraft armed with LRASM. I'm agreeing with the idea that until they get a flush-deck CV with catapults their naval aviation is primarily going to be for fleet air defense only. In all the photos of SU-33's taking off from the Russian carrier, never once have I seen those aircraft with external loads. Think there might be a reason for that?
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Post by steel selachian on Jan 13, 2015 21:13:23 GMT -6
Because they can't?
Fun note - I was nosing around and found a Blogspot post with some purported links talking about future PLAN carrier construction. None of them were what I would call credible sources, and one in particular was funny; it purported to show a photo of the "new carrier" under construction but it was pretty clear it was a shot of the old Kiev-class Admiral Gorshkov being fitted with a skijump ramp at Severodvinsk for her conversion as INS Vikramaditya.
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Post by oldpop2000 on Jan 14, 2015 8:22:15 GMT -6
Because they can't? Fun note - I was nosing around and found a Blogspot post with some purported links talking about future PLAN carrier construction. None of them were what I would call credible sources, and one in particular was funny; it purported to show a photo of the "new carrier" under construction but it was pretty clear it was a shot of the old Kiev-class Admiral Gorshkov being fitted with a skijump ramp at Severodvinsk for her conversion as INS Vikramaditya. We, in the western world, need to be careful of not being manipulated by the carrier advocates about this issue of Chinese carriers. It's similar to the early 1900's when the same type of group manipulated information and attitudes about the dreadnoughts the German's were building. The phrase "we want eight and we won't wait" pushed the British government into conflict over information about increased nickel purchases by Krupp. It was assumed it meant more heavy guns and battleships. It didn't, but it worked. The Navy advocates got their four extra battleships. As I have posted, the development of carriers and aircraft takes time. The Chinese don't have an experienced country helping them. Their carriers force is not a threat now but might be in the future, but I don't really think so. Economics in their country and societal pressures might change their direction.
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Post by oldpop2000 on Jan 14, 2015 13:31:03 GMT -6
This link shows thrust to weight ratios for many different aircraft and the formula for calculating it. We should adopt this in any of our discussions.
defenceforumindia.com/thrust-to-weight-ratio-fighter-plane-460
Update: I began to think of other problems that have to be addressed with ski ramps. One of them is the weight transfer to the main landing gears as the aircraft enters the ramp. This will require some real off line testing and beefing up of the main wing structure and attachment point of the wings to the fuselage. This will, of course, add weight. Another issue is weapons physical clearance of the minimum clearance distances of the ramp. Flat tires and bad struts could result in total elimination of the ramp and now the main launch point of the carrier is out of service.
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Post by steel selachian on Jan 14, 2015 19:30:44 GMT -6
Because they can't? Fun note - I was nosing around and found a Blogspot post with some purported links talking about future PLAN carrier construction. None of them were what I would call credible sources, and one in particular was funny; it purported to show a photo of the "new carrier" under construction but it was pretty clear it was a shot of the old Kiev-class Admiral Gorshkov being fitted with a skijump ramp at Severodvinsk for her conversion as INS Vikramaditya. We, in the western world, need to be careful of not being manipulated by the carrier advocates about this issue of Chinese carriers. It's similar to the early 1900's when the same type of group manipulated information and attitudes about the dreadnoughts the German's were building. The phrase "we want eight and we won't wait" pushed the British government into conflict over information about increased nickel purchases by Krupp. It was assumed it meant more heavy guns and battleships. It didn't, but it worked. The Navy advocates got their four extra battleships. As I have posted, the development of carriers and aircraft takes time. The Chinese don't have an experienced country helping them. Their carriers force is not a threat now but might be in the future, but I don't really think so. Economics in their country and societal pressures might change their direction. I seem to recall we've also been here more recently - in the 1970s and 1980s, the US was looking at the Soviet aircraft carrier program, as well as large surface combatants such as the Kirov and Slava, and assumed they were building a blue-water power projection fleet to challenge us at sea. That helped kick off the "600-Ship Navy," which while it built the backbone of the post-Cold War USN arguably hurt us to a degree in the long run (naval aviation in particular felt the pain; what money wasn't sucked up by ship construction and modernization was eaten by the A-12 Avenger program). Later we realized that the Soviets had no intention of sending their fleet out for a battle royale in the open ocean - all that hardware was supposed to stay close to Russian territorial waters and keep our carrier groups and subs from hunting in the boomer bastions.
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Post by steel selachian on Jan 14, 2015 23:04:26 GMT -6
This link shows thrust to weight ratios for many different aircraft and the formula for calculating it. We should adopt this in any of our discussions.
defenceforumindia.com/thrust-to-weight-ratio-fighter-plane-460
Update: I began to think of other problems that have to be addressed with ski ramps. One of them is the weight transfer to the main landing gears as the aircraft enters the ramp. This will require some real off line testing and beefing up of the main wing structure and attachment point of the wings to the fuselage. This will, of course, add weight. Another issue is weapons physical clearance of the minimum clearance distances of the ramp. Flat tires and bad struts could result in total elimination of the ramp and now the main launch point of the carrier is out of service. Here's another question I have with ski ramps and with carrier design in general - wind over the bow. Historically, carriers have been fast ships. Not just because you want to get from one place to another quickly, but because every knot of wind over the bow helps get your birds in and out of the air in an easier fashion. The fleet carrier classes of WWII all had top speeds of 30 knots or better, and even though the aircraft they were launching were prop birds much lighter than modern carrier aircraft they still needed catapult launches on occasion for an extra push. The US supercarriers have all had top speeds of over 30 knots; so did the British Audacious-class and the French Clemenceau-class. Now if you look at some other modern carriers, they're slower than their WWII ancestors. The Charles de Gaulle was only designed to make 27 knots, and early on she was unable to make her design speed due to propeller issues. The Queen Elizabeths are listed with a design speed "in excess of 25 knots." The Kuznetsov reportedly tops out at 29 knots. With the exception of the Charles de Gaulle, these ships lack catapults. The QEs are at least using STOVL aircraft, but the Kuznetsov and Liaoning are operating large, heavy CTOL jets. How much of a loss is that 5-10 knot reduction in speed when it comes to aircraft operations?
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