Payload accelerate after rocket separation?

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Discussion Overview

The discussion centers around the acceleration of a torpedo after its separation from a rocket motor during the launch of the ASROC system. Participants explore the mechanics of this separation, including the forces involved and the potential for additional acceleration experienced by the torpedo post-separation. The scope includes technical explanations and conceptual clarifications related to physics and engineering principles.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that the torpedo may experience further acceleration after separation due to the dynamics of the separation event, although this seems unlikely to others.
  • One participant references Newton's second law (F=ma) to argue that stopping the force would stop the acceleration, suggesting that any additional acceleration would only be due to gravity if the torpedo were on a downward trajectory.
  • Another participant suggests that if the separation was caused by a small explosion, the resulting force could provide a "push" to the torpedo, potentially contributing to its acceleration.
  • A detailed description of the physical setup of the torpedo and rocket motor is provided, including the mechanism of separation and the forces involved, indicating that the separation occurs during an upward excursion.

Areas of Agreement / Disagreement

Participants express differing views on whether the torpedo experiences additional acceleration after separation. While some propose that forces from the separation event could contribute to this, others argue against it based on established physical principles. The discussion remains unresolved with multiple competing views present.

Contextual Notes

Participants reference the mechanics of separation and the forces involved, but there are limitations in the discussion regarding the specifics of the explosion's impact and the exact conditions during the separation event. Some assumptions about the torpedo's trajectory and the nature of the forces at play are not fully explored.

MotoMike
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The USN used to shoot ASROC from box launchers. It was a torpedo with a rocket motor on the back. it was ballistic. The rocket fired and then separated mid flight. the torpedo continued on, a chute was deployed to slow and I think stabilize the water entry after which the torpedo went on about it's business.

I was told by an engineer that was aboard one time that at the point of separation when the motor stopped, and the air-frame separated and the freed torpedo continued on, that the torpedo experienced a bit of further acceleration. It seemed unlikely to me, but I was assured that it was so.

can anyone help me out?

thanks, Mike
 
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MotoMike said:
The USN used to shoot ASROC from box launchers. It was a torpedo with a rocket motor on the back. it was ballistic. The rocket fired and then separated mid flight. the torpedo continued on, a chute was deployed to slow and I think stabilize the water entry after which the torpedo went on about it's business.

I was told by an engineer that was aboard one time that at the point of separation when the motor stopped, and the air-frame separated and the freed torpedo continued on, that the torpedo experienced a bit of further acceleration. It seemed unlikely to me, but I was assured that it was so.

can anyone help me out?

thanks, Mike
By F=ma, when you stop the force you stop the acceleration. If the torpedo were on a downward trajectory, it might get some additional acceleration due to gravity if it were not already at its terminal velocity.
 
Thanks very much Berkeman. That makes sense to me. As I understand it he was alluding to some energy being transferred from the loss of mass. I didn't think it made sense, but he was a rocket scientist after all.
 
MotoMike said:
I was told by an engineer that was aboard one time that at the point of separation when the motor stopped, and the air-frame separated and the freed torpedo continued on, that the torpedo experienced a bit of further acceleration. It seemed unlikely to me, but I was assured that it was so.
If the separation was brought about by a small explosion, the force of that explosion would affect both the torpedo and the air-frame (but in opposite directions). Thus, the torpedo could very well have gotten a "push" from the separation event.
 
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The torpedo and rocket motor were held together by a center section. basically an aerodynamic tube split in half lengthwise. It fit over the aft of the torpedo hiding its control surfaces and chute pack. And around the front of the rocket motor. two bands, one in front and one in the back secured it in place. The explosion that takes place that breaks the bands loose is quite powerful. I don't recall just how that worked, but thought the forces would be radial. the rocket motor immediately falls away. while the torpedo continues on. the separation occurs on the upward excursion. attached is an image that is as I recall them.

asroc.jpg
 

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