Cancun Trip Packages - Catapult on a Navy Aircraft Carrier

There are two aspects left out that seem pertinent to me (as both an engineer and retired Navy engineer): Something along the lines of a steam piston pumped up in pressure until a specially designed part breaks and the aircraft is flung into the air. How can such launching speeds are attained with the referenced system.

The launching valve is a very fast opening-closing valve. 1.

Essentially a large insulated tank, steam is "stored" in a steam accumulator, prior to the launching valve. 2.

Since it's a one-time use device, the aircraft carrier carries a literal truckload of the holdback devices for the duration of the voyage. The "holdback device" is the part that breaks. Length of time the valve is open is calculated based on take off velocity and weight of the aircraft, there is definitely a quick acting launch valve. 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.

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, to do that on a carrier. The aircraft can be held against the brakes until the engine is developing full thrust, for ground-based operations.

And must be refilled periodically, and the water does get very hot, this is accomplished by using a "water brake". The pistons that are pushed forward by the steam need to decellerate from ~160 mph to zero in a matter of feet, on the catapult. Not the arresting gear, but this is part of the catapult, it is a Water-Brake. I don't believe water is used as a hydrauli fluid in the arresting gear machinery.

" "engine fluid" but never "water; ditto the LSO manual. But it only mentions "fluid" in the context of the arresting gear, the carrier manual NAEC-MISC-06900 is also a good authority. Note that the manual discusses the importance of pre-heating the entire assembly to ensure that the steam's energy is not wasted in heating up mechanical components. The built-up steam then expands to push the piston and aircraft forward, the holdback device is also called a tension bar and when that breaks. The launching valves have adjustable orifices control the pressure of the steam into the pistons, according to the LSO manual. A lot of land based arresting gear is water-filled - I'd be surprised if the shipborne stuff was significantly different. Don't take fresh water too casually.

It's far easier to turn 211 degree water into steam than to boil seawater from scratch! Very little of the steam escapes the catapult- the vast majority of it is reclaimed and reheated.

It's incredible, all that massive steel and it still moves under the stresses. And I tell you what- the entire bow of the ship shakes when the catapult slams into the water brake! And the bow and stern as cantelievers, as is the water brake- ships are designed as a giant cantilever beam with most of the displacement in the center, the structure supporting the catapult is incredible.

Assuming steam leaks are minimal, i believe as the equivalent of over a hundred gallons of water is lost on each cat shot. This is relative, "Very little steam" escapes. Including even the possibility of the ram hanging up, i suspect there will be significant mechanical problems, if one were to try to operate the catapult without the system being heated and expanded. They will expand significantly (I don't recall the numbers) from ambient to operating. Catapults expand when heated, like most metallic systems. Pre-heating has other purposes as well.

You'd never even know they were launching or recovering aircraft, if you're down 2nd deck and below aft of about frame 100 or so. There's a little bit of noise but not really any noticeable vibration and there's so much noise from elsewhere it's drowned out, i mean. Or the waist cats much outside of the sponson, you can't really feel the bow cats outside of the bow. You can feel it everywhere on the ship, its not just the bow of the ship sthat "shakes" on launch, from my experience!

It's a difference in carriers, perhaps. Instead we just see a tiny bit of seepage, it would lose pressure and stop accelerating towards the end; if you were losing that much steam over the length of the catapult. Maybe ten gallons at the most, a couple of gallons, there just isn't that much steam coming through the slit, but I can guarantee they're not loosing a hundred gallons of water during launch, i think they use a lot of steam.