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#1
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STOVL and CTOL from big decks - deconflicting ?
I'm merely an amateur observer, but it looks like there are a couple of issues. Deployment to theater - means one fewer USN CTOL squadrons aboard the carrier once in theater. This might not be a big deal if you are mostly tasked with CAS for Marines, but for a large campaign using two CVNs, would they configure both air wings with a Marine squadron or not ? Cyclic ops - CTOL has long operated with tightly timed launches and deployments - do you launch and recover CTOL a/c together and STOVL together, but never mix types ? How do you change over deck if you are landing a stack of CTOL a/c and a STOVL has a an emergency landing ? Are they planning deck run takeoffs with JSF ? (!!!!!) ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
#2
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"John S. Shinal" wrote:
I'm merely an amateur observer, but it looks like there are a couple of issues. Deployment to theater - means one fewer USN CTOL squadrons aboard the carrier once in theater. This might not be a big deal if you are mostly tasked with CAS for Marines, but for a large campaign using two CVNs, would they configure both air wings with a Marine squadron or not ? No idea. But if the opportunity arose to move the marines ashore to an FOB, they probably would. Cyclic ops - CTOL has long operated with tightly timed launches and deployments - do you launch and recover CTOL a/c together and STOVL together, but never mix types ? That certainly can be an issue, but with the reduced airgroups there may well be room to do both simultaneously. Perhaps the angle will be used by the STOVL a/c to make free runs, while the bow cats shoot off the rest, or vice-versa (this will require some experiment). The ability of STOVL a/c to make simultaneous or near simultaneous landings (by section or on CVs, even by division) probably makes landings, at least, a non-issue. How do you change over deck if you are landing a stack of CTOL a/c and a STOVL has a an emergency landing ? Where's the problem? Even assuming that the STOVL a/c can't just find a piece of empty deck starboard, it can just get in the regular pattern. It's not as if they have to reconfigure the deck (or do emergency pull-forwards), as would be the case with a conventional carrier a/c declaring an emergency. Are they planning deck run takeoffs with JSF ? (!!!!!) Sure (I assume you're referring to the F-35B). FAIK they could do them with the F-35Cs as well, at least when fairly light, if they've got the t/w ratio. This would return the situation to what it was in WW2, when a deck-load strike was catapulted off until there was adequate t/o run available, at which point the remaining a/c made (faster cycle) free take-offs. Typically the fighters were furthest forward as they required the shortest run, then dive bombers and/or torpedo planes. Guy |
#3
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"John S. Shinal" wrote in message ... I'm merely an amateur observer, but it looks like there are a couple of issues. Deployment to theater - means one fewer USN CTOL squadrons aboard the carrier once in theater. This might not be a big deal if you are mostly tasked with CAS for Marines, but for a large campaign using two CVNs, would they configure both air wings with a Marine squadron or not ? Not sure what your concern might be. Marine squadrons routinely deploy on CVs today (and have for some time). For the most part, they fly the same missions that their Navy counterparts fly. Cyclic ops - CTOL has long operated with tightly timed launches and deployments - do you launch and recover CTOL a/c together and STOVL together, but never mix types ? It remains to be seen how the cycle would be run with STOVL JSFs. AV-8As deployed on FDR in the late 70s, so it's not impossible. There is some additional flexibility that comes with the ability to stop and land, but it will be interesting to see how the Navy uses it. There will be great inertia to make it operate like the conventional cat-trap aircraft on board. How do you change over deck if you are landing a stack of CTOL a/c and a STOVL has a an emergency landing ? What's to change? Are they planning deck run takeoffs with JSF ? (!!!!!) Absolutely. ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
#4
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"John S. Shinal" wrote...
Cyclic ops - CTOL has long operated with tightly timed launches and deployments - do you launch and recover CTOL a/c together and STOVL together, but never mix types ? For timing purposes, it shouldn't be much different than a mixed A-6 / F-4 or F-14 / F-18A/B flight deck -- the cycle time is controlled by the shortest endurance. In the case of the former, there was enough organic tanker support to keep the F-4s alive for a 1+45 cycle. In the latter case, the F-18s dominate, and normal cycle times are reduced to 1+30 or less. When you come to a F-18 / F-35 STOVL loadout, there could be a LOT of F-18 tankers supporting 1+30 cycles for the F-35, or the cycle times will be reduced to 1+15 or less. OTOH, maybe cyclic ops will become history, and "flex deck" will become the norm... OTOOH, I don't see the F-18 / F-35 STOVL loadout as a "normal" loadout... How do you change over deck if you are landing a stack of CTOL a/c and a STOVL has a an emergency landing ? That's not a problem at all -- the landing area is clear, and you just delta the CTOL until the emergency gets aboard. |
#5
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John R Weiss wrote:
"John S. Shinal" wrote... Cyclic ops - CTOL has long operated with tightly timed launches and deployments - do you launch and recover CTOL a/c together and STOVL together, but never mix types ? For timing purposes, it shouldn't be much different than a mixed A-6 / F-4 or F-14 / F-18A/B flight deck -- the cycle time is controlled by the shortest endurance. In the case of the former, there was enough organic tanker support to keep the F-4s alive for a 1+45 cycle. In the latter case, the F-18s dominate, and normal cycle times are reduced to 1+30 or less. When you come to a F-18 / F-35 STOVL loadout, there could be a LOT of F-18 tankers supporting 1+30 cycles for the F-35, or the cycle times will be reduced to 1+15 or less. snip Don't see why. The F-35B will have considerably more internal fuel than an F-18A-D with similar weight, a single engine and no need for 3-5,000 lb. of recovery fuel reserve. Marine profile mission radius (KPP) is 450nm from a 550' STO (590nm for the USAF F-35A mission profile; 600nm for the USN F-35C mission profile), with a VL bringback of .2 x 1k JDAMs and a pair of AIM-120s, plus reserve fuel. Guy |
#6
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"Guy Alcala" wrote...
When you come to a F-18 / F-35 STOVL loadout, there could be a LOT of F-18 tankers supporting 1+30 cycles for the F-35, or the cycle times will be reduced to 1+15 or less. Don't see why. The F-35B will have considerably more internal fuel than an F-18A-D with similar weight, a single engine and no need for 3-5,000 lb. of recovery fuel reserve. Marine profile mission radius (KPP) is 450nm from a 550' STO (590nm for the USAF F-35A mission profile; 600nm for the USN F-35C mission profile), with a VL bringback of .2 x 1k JDAMs and a pair of AIM-120s, plus reserve fuel. What are the comparative thrust and specific fuel consumptions of the 2 airplanes' powerplants? What will the fuel burn be for a typical approach and vertical landing for the F-35? Why will there be a significantly lesser fuel reserve requirement? Will the bingo fuel requirement be less for a STOVL airplane than a CTOL airplane? The F/A-18 hasn't met fuel specs yet, to my knowledge. The A/B/C/D never met the original requirements, and the C/D specs were "adjusted" so much from the original requirements that it is almost impossible to make an apple-apple comparison. So far, I believe the combination of cost and performance requirements for the F-35 are hopelessly optimistic... |
#7
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"John R Weiss" wrote:
What are the comparative thrust and specific fuel consumptions of the 2 airplanes' powerplants? What will the fuel burn be for a typical approach and vertical landing for the F-35? There is some scant info from RN 801 Squadron in their Falklands ops on INVINCIBLE. ISTR that Sharkey Ward insisted they use their fuel on CAP and not in the pattern, with some *really* low fuel loads at land-on, and not much burned during their approach and translation maneuver. Most 801 flights were 2 ship CAPs. Is there a USN "best practice" for fuel load at the trap ? Five minutes of fuel at a given SFC, or something like that ? ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
#8
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"John S. Shinal" wrote:
There is some scant info from RN 801 Squadron in their Falklands ops on INVINCIBLE. ISTR that Sharkey Ward insisted they use their fuel on CAP and not in the pattern, with some *really* low fuel loads at land-on, and not much burned during their approach and translation maneuver. Most 801 flights were 2 ship CAPs. Policies during actual wartime may differ significantly from "peacetime" practice. Actually saving the ships from incoming missiles tends to make a single airplane a reasonable trade... Is there a USN "best practice" for fuel load at the trap ? Five minutes of fuel at a given SFC, or something like that ? That has evolved through the years, based on experience, changing tactics, and risk-averse trends on the part of the upper echelons... In my 81-83 A-6 cruise on Midway, our daytime minimum was 3.5-4.0 (3500-4000 lb at landing), and 4.0-5.0 at night. By the time I got to Kitty Hawk in 87, it was 5.0-5.5 day and max trap (6.0-7.5, depending on airframe and loadout) at night. Nimitz 88-89 was essentially max trap all the time... I don't know what the current state of affairs is... Unless the ship is working "blue water" (no divert field available), min landing fuel is usually the fuel required for divert. In "blue water" ops, numbers similar to those I cited above come into play. Generally, 2 looks at the ball (maybe 3 at night) plus min landing fuel for the airplane (e.g., 2.0 for the A-6). |
#9
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On 3/4/04 10:26, in article yMI1c.178613$uV3.756299@attbi_s51, "John R
Weiss" wrote: "John S. Shinal" wrote: There is some scant info from RN 801 Squadron in their Falklands ops on INVINCIBLE. ISTR that Sharkey Ward insisted they use their fuel on CAP and not in the pattern, with some *really* low fuel loads at land-on, and not much burned during their approach and translation maneuver. Most 801 flights were 2 ship CAPs. Policies during actual wartime may differ significantly from "peacetime" practice. Actually saving the ships from incoming missiles tends to make a single airplane a reasonable trade... Weapons bring back typically influences these policy decisions. Is there a USN "best practice" for fuel load at the trap ? Five minutes of fuel at a given SFC, or something like that ? That has evolved through the years, based on experience, changing tactics, and risk-averse trends on the part of the upper echelons... SNIP Case I "charlie" (day/VMC) is tank plus three passes (2.5 +.4 + .4 + .4) or 3.7. Case II/III (night/IMC) "charlie" is night tank plus two passes (3.0 + .8 + ..8) or 4.6. All this is from memory (i.e. I know the numbers [3.7/4.6] are correct, but the calculation method may be slightly off without refreshing my knowledge). Other carrier guys feel free to jump in and correct me. --Woody |
#10
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John R Weiss wrote:
"Guy Alcala" wrote... When you come to a F-18 / F-35 STOVL loadout, there could be a LOT of F-18 tankers supporting 1+30 cycles for the F-35, or the cycle times will be reduced to 1+15 or less. Don't see why. The F-35B will have considerably more internal fuel than an F-18A-D with similar weight, a single engine and no need for 3-5,000 lb. of recovery fuel reserve. Marine profile mission radius (KPP) is 450nm from a 550' STO (590nm for the USAF F-35A mission profile; 600nm for the USN F-35C mission profile), with a VL bringback of .2 x 1k JDAMs and a pair of AIM-120s, plus reserve fuel. What are the comparative thrust and specific fuel consumptions of the 2 airplanes' powerplants? Actual thrust numbers, SFC, BPR, pressure ratio etc. are all still unavailable for the F135 and 136; basic layout (turbine and compressor stages) is about all that you can find. P&W & GE both just say "40,000 lb. thrust class." I've seen somewhere (but can't find it) that Rolls-Royce mentioned ca. 34,000 lb. dry, 56,000 lb. wet for the F136, but that may include the lift fan. The F136 is based on the F120 design, and IIRR that engine was variable-cycle. The use of the lift fan eliminates the Harrier problem of needing a very high bpr to generate sufficient lift for VTOL, screwing the SFC in throttled back cruise or at high CAS. As to the F-18A-D, off the top of my head F404-400s were rated at about 10,800 lb. mil (or maybe that was the internal fuel), 16,000 lb. A/B, with the -402 boosted to 17,600 lb. max. A/B. What will the fuel burn be for a typical approach and vertical landing for the F-35? Considering how low it was for the Harrier, with the F-35B being easier to control, it should be minimal. Harrier transition and landing takes a minute (or two at the outside), with max. fuel burn (wet) of 220 lb./minute for the -406, and presumably a bit more for the -408. The F-35B probably has between 50 and 100% more power in the hover, with a newer engine design and using an optimized lift fan plus a less-optimized core engine, so you can make your own estimates. Why will there be a significantly lesser fuel reserve requirement? Because there's no little need for multiple looks at the deck -- no bolters, no fouled decks. Enough fuel for one go-around seems to be about the max required, at least in wartime. Peacetime requirements will undoubtedly be greater, but still considerably less. Will the bingo fuel requirement be less for a STOVL airplane than a CTOL airplane? Are you referring to bingo fuel to the beach, or mission bingo? You have little need for the former. In Sherman Baldwin's book "Ironclaw," he describes the Midway trying to get a single F-18 back on board at night just prior to DS, while they were running at 30 knots or so, directly towards Iranian territorial waters. IIRR they tanked the guy a couple of times, and spent an hour getting him aboard. Just about the time they were going to have to bingo him because they had to change course to stay out of Iranian waters, they got him aboard. None of that would have been necessary if he'd been flying a STOVL a/c. The Midway could have been cruising along at any speed above steerage way, and he would have recovered on the first pass. For mission bingo, it has been less for Harriers. As John Shinal alluded to, during the Falklands war, the CO of 801 Squadron told his pilots that if they landed back on board with more than 800 lb. of fuel from a CAP mission, he'd "put his boot up their arse." Average fuel at land on seems to have been under that, in the 600 lb. range, with several landings with 400 lb., and in at least one case, when the visibility was perhaps 50 feet in fog and the pilot in question made one missed approach and then had the carrier shine a spotlight straight up, descending vertically next to it and landing on without ever seeing the deck or the island (or they him), 200 lb. Flight ops had already been shut down prior to his recovery. Over Bosnia, USN F-18s were originally operating with 5,000 lb. landing reserves, subsequently cut to 3,500 lb. to increase weapons bringback. Even being really generous, it's hard to see why an F-35B would need more than 2,000 lb. landing reserve. Night landings, even Case III, just aren't the same white-knuckle affair that they are when you have to trap. The F/A-18 hasn't met fuel specs yet, to my knowledge. The A/B/C/D never met the original requirements, and the C/D specs were "adjusted" so much from the original requirements that it is almost impossible to make an apple-apple comparison. The F-18E/F supposedly meets the original F-18A spec. The threshold radius for the F-35B is greater than that. So far, I believe the combination of cost and performance requirements for the F-35 are hopelessly optimistic... Aren't they all? But they are paying a lot more attention to cost ceilings on the program than they've done in the past; that is indeed one of the prime drivers. We'll just have to see how the performance falls out. Guy |
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