Type 054B/next generation FFG thread


blindsight

Junior Member
Registered Member
Diesels are not that loud, it is gas turbines that tend to have extreme noise levels at higher output levels. A standard diesel set up is probably pretty comparable to a gas turbine IEPS set up when it comes to noise levels at high speeds.

Overall, a 4000 ton diesel frigate has much less to gain from IEPS than a 7500-14000 ton gas powered destroyer.
It's not just about the noise itself. Gas turbine tends have some higher-frequency noises that's easier to cancel using hydraulic dampers. Diesels have lower-frequency noises, which is harder to deal with.
 

Tam

Brigadier
Registered Member
I have no idea why you brought up Tianwen here. Do you really think that's comparable? Or even a related topic?
...

Yes, because every system needs to pass thorough testing on the ground, with the testing simulated to create the conditions of the operating environment. The whole principle of testing and quality control applies here as it applies to the space project.

Testing policies and principles are applied universally regardless whether its a space, air, land, or ship project. Good example. WS-10 wasn't ready based on PLAAF's own standards for the J-10, so they did not install it on the J-10 for a long time even if the WS-10 was applied to the J-11. Only when the WS-10 took its game a notch, when its finally ready for the J-10 then it goes to the J-10. None of the support the local industry and help develop the indigenous technology arguments matter here. If it doesn't meet their tests, it doesn't pass. If it meet their tests, it passes. Its that simple.

They don't operate half assed.
 
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Tam

Brigadier
Registered Member
It's not just about the noise itself. Gas turbine tends have some higher-frequency noises that's easier to cancel using hydraulic dampers. Diesels have lower-frequency noises, which is harder to deal with.

Hydraulic dampeners can also cancel out lower frequency noises, and they did exactly just that for the 054A and 056 series. You can also reduce vibrations further with viscous dampers, counterbalancing or contrarotating shafts, flexible engine mounts, stiffening the engine block, and even to controlling the fuel injection.
 

blindsight

Junior Member
Registered Member
Yes, because every system needs to pass thorough testing on the ground, with the testing simulated to create the conditions of the operating environment. The whole principle of testing and quality control applies here as it applies to the space project.

Testing policies and principles are applied universally regardless whether its a space, air, land, or ship project. Good example. WS-10 wasn't ready based on PLAAF's own standards for the J-10, so they did not install it on the J-10 for a long time even if the WS-10 was applied to the J-11. Only when the WS-10 took its game a notch, when its finally ready for the J-10 then it goes to the J-10. None of the support the local industry and help develop the indigenous technology arguments matter here. If it doesn't meet their tests, it doesn't pass. If it meet their tests, it passes. Its that simple.

They don't operate half assed.
I'm repeating the same words here: let's just wait and see.
 

blindsight

Junior Member
Registered Member
Hydraulic dampeners can also cancel out lower frequency noises, and they did exactly just that for the 054A and 056 series. You can also reduce vibrations further with viscous dampers, counterbalancing or contrarotating shafts, flexible engine mounts, stiffening the engine block, and even to controlling the fuel injection.
I didn't say you can't. It's just about how good the results are. It's naturally harder to filter low frequency noises out. That's it.
 

Tam

Brigadier
Registered Member
I didn't say you can't. It's just about how good the results are. It's naturally harder to filter low frequency noises out. That's it.

Naturally harder does not make it impossible. Not to mention this has all be done decades ago in every sector that uses a diesel engine.
 

blindsight

Junior Member
Registered Member
Hydraulic dampeners can also cancel out lower frequency noises, and they did exactly just that for the 054A and 056 series. You can also reduce vibrations further with viscous dampers, counterbalancing or contrarotating shafts, flexible engine mounts, stiffening the engine block, and even to controlling the fuel injection.
It's similar for cars, for example. You have a lot of engine configurations, such as V6, having inherent 1st order imbalance, but in most cases, for example, most 60-degree V6s, you just live with it because hydraulic engine mount and other normal dampening mechanism does the job well. However, for I4 with inherent 2nd order imbalance, usually you would need counter-rotating twin balancer shafts to help cancel the vibration, although the absolute amount of NVH is actually weaker. That's all because of the higher frequency nature of this 2nd order thing.
 

Tam

Brigadier
Registered Member
You'll have to pay. lower efficiency, lower output...

Tell that to the shipbuilders and ship buyers.

Despite electrical propulsion, despite gas turbines, despite the shilling the makers of such, more and more each year, new ships are built with reciprocating engines.
 

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