Trump Orders Navy to Restore Older Tech on Aircraft Carriers, Costing Billions

[brovane]

The steam catapults are a lot bigger than the EMALS and need a steam buffer, and a lot of pipework. So retrofitting steam catapults is essentially a complete redesign between the flight deck and the keel. So 10 years. Fun factoid each launch uses the same energy as 4 gallons of diesel. The steam is desalinated water so you vastly increase the water usage. The catapults are only 5% efficient.

Wasn't one of the reason for going to EMALS that it allows you easily vary the catapult force from a unmanned drone to a fully load Super Hornet?

[Nightwatch2]

The steam catapults are a lot bigger than the EMALS and need a steam buffer, and a lot of pipework. So retrofitting steam catapults is essentially a complete redesign between the flight deck and the keel. So 10 years. Fun factoid each launch uses the same energy as 4 gallons of diesel. The steam is desalinated water so you vastly increase the water usage. The catapults are only 5% efficient.

Wasn't one of the reason for going to EMALS that it allows you easily vary the catapult force from a unmanned drone to a fully load Super Hornet?

so can steam

[Nik_SpeakerToCats]

Steam catapults are okay, but the plumbing 'tail' is horrendous.

Bit like pneumatic 'dynamite' guns, their time seems to have passed.

Especially with so many systems now demanding more and more electrical power, ranging from Radar, via anti-drone 'microwave' and 'laser' zappers to electric-driven CIWS turrets and their feed systems, to possible future rail-guns...

MilSpec seems to shun electric side-thrusters and 'podded' drives, but their time will come.

Snark:
I'm surprised 'King Coal' hasn't had a word in that trumpet-like ear to suggest reversion to trad stokers...
/

[Nightwatch2]

Steam catapults are okay, but the plumbing 'tail' is horrendous.

Bit like pneumatic 'dynamite' guns, their time seems to have passed.

Especially with so many systems now demanding more and more electrical power, ranging from Radar, via anti-drone 'microwave' and 'laser' zappers to electric-driven CIWS turrets and their feed systems, to possible future rail-guns...

MilSpec seems to shun electric side-thrusters and 'podded' drives, but their time will come.

Snark:
I'm surprised 'King Coal' hasn't had a word in that trumpet-like ear to suggest reversion to trad stokers...
/

Oh yea….

A better solution than King Coal that would avoid all of those plumbing and fuel issues would be -

Sails and galley oars

[brovane]

The steam catapults are a lot bigger than the EMALS and need a steam buffer, and a lot of pipework. So retrofitting steam catapults is essentially a complete redesign between the flight deck and the keel. So 10 years. Fun factoid each launch uses the same energy as 4 gallons of diesel. The steam is desalinated water so you vastly increase the water usage. The catapults are only 5% efficient.

Wasn't one of the reason for going to EMALS that it allows you easily vary the catapult force from a unmanned drone to a fully load Super Hornet?

so can steam

Is this not accurate?

For low-weight drone aircraft, the Electromagnetic Aircraft Launch System (EMALS) is vastly superior to traditional steam catapults. EMALS uses a software-controlled linear induction motor that allows precise, low-end thrust tuning, whereas steam systems deliver a violent, rigid power surge that can tear apart or over-stress lightweight, fragile unmanned airframes.

[Nightwatch2]

Wasn't one of the reason for going to EMALS that it allows you easily vary the catapult force from a unmanned drone to a fully load Super Hornet?

so can steam

Is this not accurate?

For low-weight drone aircraft, the Electromagnetic Aircraft Launch System (EMALS) is vastly superior to traditional steam catapults. EMALS uses a software-controlled linear induction motor that allows precise, low-end thrust tuning, whereas steam systems deliver a violent, rigid power surge that can tear apart or over-stress lightweight, fragile unmanned airframes.

I think that’s accurate. My point was/is that steam catapults are also dialed up or down for the aircraft weight and desired end speed.

It does, however, give it a “jolt” rather than EMALS smooth acceleration.

I am not arguing in favor of steam! (Caveat about EMCON still stands)

[kdahm]

I believe, although I'm not certain, that the issue is that steam catapults have a certain minimum impulse, and they have a definite acceleration jolt at the beginning. It's because of releasing high pressure (comparatively) steam into a cylinder arrangement, and getting enough force to get the piston and carriage assembly moving. Also, because the cylinder is constantly expanding, it requires additional steam regardless of the weight of the plane.

In contrast, the EMALS system can be tuned, can have a fairly low acceleration throughout it's travel regardless of the weight of the plane, and the acceleration is much more proportional to plane weight. That means that a drone can start off slow and increase acceleration down the track and the minimum energy used is much lower.

[Nightwatch2]

I believe, although I'm not certain, that the issue is that steam catapults have a certain minimum impulse, and they have a definite acceleration jolt at the beginning. It's because of releasing high pressure (comparatively) steam into a cylinder arrangement, and getting enough force to get the piston and carriage assembly moving. Also, because the cylinder is constantly expanding, it requires additional steam regardless of the weight of the plane.

In contrast, the EMALS system can be tuned, can have a fairly low acceleration throughout it's travel regardless of the weight of the plane, and the acceleration is much more proportional to plane weight. That means that a drone can start off slow and increase acceleration down the track and the minimum energy used is much lower.

That's my understanding too, which is why the push to EMALS.

delivery has been problematic however along with the electric weapons elevators, etc. So a lot of the push back to steam is perhaps because of the long growing pains.

we shall see over time.

[warshipadmin]

So far as the jolt goes, what is it like compared with the controlled crash at the end of each flight? Apparently the airframes don't have a defined number of takeoffs before being torn down or replaced, unlike say civil airliners where the number of pressure cycles is logged.

[Nightwatch2]

So far as the jolt goes, what is it like compared with the controlled crash at the end of each flight? Apparently the airframes don't have a defined number of takeoffs before being torn down or replaced, unlike say civil airliners where the number of pressure cycles is logged.

They are both pretty substantial!

I wouldn’t say either is harder than the other

[warshipadmin]

So effectively EMALS doubles the fatigue life of the aircraft. Sounds good.