PLAN Catapult Development Thread, News, etc.


nemo

Junior Member
compressed gas, beside being unreplenishable under water, is also less effective as depth (hence water pressure) increase. EM launch can potentially launch at any depth. Also compressed gas requires a vent, which can be another point of failure.
 

Tam

Major
Registered Member
I don't recall such systems being installed on the Virginia or Seawolf class. However, will DARPA sue China for "patent infringement" (and of course, slap tariffs) once it learns about Ma's works ????????? Haha!
Its dated 1993. Its long expired.
 

taxiya

Colonel
Registered Member
US5284106A and anything similarly based on MHD is just exotic fantacies. I know some experiments were done decades ago, but they never left lab because they are thereotically plausible but practically pointless.

A torpedo launching system with a magnetohydrodynamic (MHD) pump for torp launches is disclosed. The system comprises a sea chamber, impulse tank and launch tube. The impulse tank has a magnetohydrodynamic pump which provides a Lorentz force to the seawater within the impulse tank thereby launching the torpedo. The MHD pump comprises supercooled superconducting electromagnets and seawater electrodes set up to provide perpendicular electric and magnetic fields.
It has electrodes in sea water turning sea water to conductor. It has to use expensive helium to cool the superconductive magnet otherwise the magnetive field would be too weak or the required electricity would be unbearably high. The electrodes will inevitably decompose sea water into hydrogen and chlorine gases. This will consume most energy instead of pushing the ship. The gases will also defeat the idea of quitely launching torpedo.

Although the temperature of superconductor is raising (therefor size and cost decreasing) to be more realistic. Avoiding electrolysis of sea water is impossible based on current known physical laws and technologies.

I am sure Ma Weiming's approach is very conventional therefor enterred service. I can imagine it is very similar to EM catapult, the torpedo has metal casing which act as the metal block pulling aircraft (the linear motor's stator), the tube would be the launch rail with coils.
 

taxiya

Colonel
Registered Member
You mean, something like this?

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Ma's device is conventional linear motor like EMALS, the stator is the torpedo casing, the coils are around the tube. However this patent is turing sea-water into a stator which in turn pushes torpedo out of the tube. IMO, the patent is more or less "脱裤子放屁,多此一举“ (taking off pants to fart).
 

taxiya

Colonel
Registered Member
I just find this research paper on EM launch of missile by Naval Aeronautical and Astronautical University. The paper was published in 2015.
导弹电磁弹射器电磁兼容性研究
Research on Electromagnetic Compatibility with Missile Electromagnetic Vertical Catapult
中文摘要:
在导弹电磁弹射器发射过程中会产生强电磁场辐射,不仅会造成电磁能量的损耗,也会对系统中的电子设备产生干扰。因此,在电磁发射中需要采取一定的防护措施。文章分析了导弹电磁弹射系统的组成和工作原理,从发射线圈电磁屏蔽和电路中的抗干扰 2个方面对电磁线圈的电磁兼容性设计进行研究,并进行了仿真分析,通过比对屏蔽前后的效果,给出了一种磁线圈弹射器电磁兼容性设计的解决方案。
英文摘要:
The radiation in forceful electric power magnetic field will occur in the course of the electromagnetic missilelaunching, it not only can create the loss of energy, but also can give rise to the interference to the avionics in the system.Therefore in need to adopt the fixed protection measure the electromagnetism in the catapult. The component and the workprinciple of electromagnetic coil catapult system in the character were analyzed, two aspects anti-jammings from actapultcoil electromagnetic shield and circuit were studied to the electromagnetism compatibility design of magnet coil with simu.lation. By way of comparing the effect of shield one kind of settlement was given out to slove electromagnetic compatibility.
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Some thoughts:
  1. We have seen the EM launching torpedo tube test-bed in 2016 CCTV documentary.
  2. The paper is published in 2015. It is likely that missile EM launcher was in the making by 2015 already since the two are essential the same except the orientation and higher water resistance.
  3. Missile launcher uses coils around the tube, so probably the same for torpedo.
  4. The paper said that it is capacitors to charge the coils. It is reasonable as the launching energy demand is much less than aircraft making the Energy Density (by volume) disadvantage of capacitor neglectable.
  5. The EM VLS launcher is in the making. There is a chance that we may see its application on new destroyers.
 

SamuraiBlue

Captain
I just find this research paper on EM launch of missile by Naval Aeronautical and Astronautical University. The paper was published in 2015.

View attachment 63498
Some thoughts:
  1. We have seen the EM launching torpedo tube test-bed in 2016 CCTV documentary.
  2. The paper is published in 2015. It is likely that missile EM launcher was in the making by 2015 already since the two are essential the same except the orientation and higher water resistance.
  3. Missile launcher uses coils around the tube, so probably the same for torpedo.
  4. The paper said that it is capacitors to charge the coils. It is reasonable as the launching energy demand is much less than aircraft making the Energy Density (by volume) disadvantage of capacitor neglectable.
  5. The EM VLS launcher is in the making. There is a chance that we may see its application on new destroyers.
Sound a bit risky with possible EM pulse that could spark a miss-fire detonation signal within the torpedo resulting to an explosion during launch.
 

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