CATAPULT ON AN AIRCRAFT CARRIERl
CATAPULT ON AN AIRCRAFT CARRIERl
(OP)
How can such launching speeds be attained with the referenced system . I have always been fascinated by such system yet I have no idea about its mechanics. An explanation is appreciated





RE: CATAPULT ON AN AIRCRAFT CARRIERl
I've got the USN carrier manual at work. I'll read up next week and see if there's a better answer
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
http://www.fas.org/man/dod-101/sys/ship/cv.htm
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
1. The launching valve is a VERY FAST opening-closing valve.
2. Prior to the launching valve, steam is "stored" in a steam accumulator, essentially a large insulated tank.
The combination of the accumulator and launching valve is what delivers a large amount of high temperature and high pressure steam to the pistons in a very short time.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
RE: CATAPULT ON AN AIRCRAFT CARRIERl
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
For ground-based operations, the aircraft can be held against the brakes until the engine is developing full thrust. To do that on a carrier, you'd need to find some way of coordinating brake release with steam valve opening - and it's probably easier just to have a weak link in the system instead.
A.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
RE: CATAPULT ON AN AIRCRAFT CARRIERl
Just a matter of trying to prevent the system from rotting away (but that's ships for you).
A.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
What the link refered to was a Water-Brake, but this is part of the catapult, not the arresting gear. On the catapult, the pistons that are pushed forward by the steam need to decellerate from ~160 mph to zero in a matter of feet. This is accomplished by using a "water brake", and yes, the water does get very hot, and must be refilled periodically.
Last - don't take fresh water too casually. My engineers were the ones that had to make it!
RE: CATAPULT ON AN AIRCRAFT CARRIERl
A.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
The carrier manual NAEC-MISC-06900 is also a good authority, but it only mentions "fluid" in the context of the arresting gear. Ditto the LSO manual; "engine fluid" but never "water."
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
The structure supporting the catapult is incredible, as is the water brake- ships are designed as a giant canteliever beam with most of the displacement in the center, and the bow and stern as cantelievers. And I tell you what- the entire bow of the ship shakes when the catapult slams into the water brake! All that massive steel and it still moves under the stresses, it's incredible.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
Like most metallic systems, catapults expand when heated. They will expand significantly (I don't recall the numbers) from ambient to operating. IF one were to try to operate the catapult without the system being haeted and expanded, I suspect there will be significant mechanical problems, including even the possibility of the "ram" hanging up.
"Very little steam " escapes......this is relative. I believe a the equivalent of over a hundred gallons of water is lost on each cat shot, assuming steam leaks are minimal.
From my experience, its not just the bow of the ship sthat "shakes" on launch, you can feel it everywhere on the ship!
RE: CATAPULT ON AN AIRCRAFT CARRIERl
I think they USE a lot of steam, but I can garuntee they're not loosing a hundred gallons of water during launch, there just isn't that much steam coming through the slit. A couple gallons, maybe tens of gallons at the most. If you WERE losing that much steam over the length of the catapult, it would lose pressure and stop accellerating towards the end; instead we just see a tiny bit of seepage.
RE: CATAPULT ON AN AIRCRAFT CARRIERl
Of course, its been so many years that I may have forgotten more than I ever knew. Of well - anchors away!
RE: CATAPULT ON AN AIRCRAFT CARRIERl
As far as I know, at least for the Carl Vinson, which is in the first group, reports are that that from aft of the hangar deck, there's no indication of the launch noise or vibration/shock, at least, that's what I was told by the electronics maintenance personel working with the CASS test systems.
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
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RE: CATAPULT ON AN AIRCRAFT CARRIERl
Three non-Nimitz class:
USS Kitty Hawk (very soon to be decommned)
USS Enterprise
USS John F. Kennedy (up in their air whether it will be decommed or extended for another decade+)
The rest are all Nimitz class:
USS Nimitz
USS Eisenhower
USS Carl Vinson
USS Theodore Roosevelt
USS Abraham Lincoln
USS George Washington
USS John C. Stennis
USS Harry S Truman
USS Ronald Reagan
And soon to be commissioned (replacing Kitty Hawk):
USS George H. W. Bush
The Enterprise is significantly different in layout and structure than the other ships. The Kennedy and Kitty Hawk have some significant differences from the Nimitz Class, but are structurally very similar and the catapults are very same design, too. Some of the older (now-decommed) ships were significant different, too. This could very well be a difference between ships of the class, or just subjective differences in what we consider "noticible" ;)
RE: CATAPULT ON AN AIRCRAFT CARRIERl
Take a look at MIL-L-22589 "Launching System, Nose Gear Type Acft"...
Regards, Wil Taylor