How Missile ballast stability works?

In summary, the author is working on a project for missiles that do not need ballast when launching from the water. However, the author notes that even an unstable ballast distribution may not tip enough to ruin the launch.
  • #1
Zahid
9
0
launching a missile from the water, how the ballast stability works?
 
Engineering news on Phys.org
  • #2
Have you considered trying a simple internet search for "ship ballast stabilization"?
 
  • #3
yes, i m working on that, but i feel like ship have big ballast system compare to missile which is 1m diameter, also i would need some exact work on, missile stability
 
  • #4
Zahid said:
launching a missile from the water, how the ballast stability works?
Zahid said:
yes, i m working on that, but i feel like ship have big ballast system compare to missile which is 1m diameter, also i would need some exact work on, missile stability
Welcome to the PF.

Your question does not make sense as you have asked it. Could you please provide a lot more detail and some sketches of what you are asking?

Missiles do not carry ballast. And ships that launch missiles would generally not need to do anything with their ballast when launching missiles, since the reaction forces involved in the launch are a tiny fraction of the weight of the ship.

https://s-media-cache-ak0.pinimg.com/originals/59/d9/29/59d9293c7f45df8e0c5a0951f2f8d0cb.jpg
59d9293c7f45df8e0c5a0951f2f8d0cb.jpg
 
  • #5
yes, you are right but what i m working on is totally different thing, have you heard about sea dragon or seabee or if you could visit to www.rippleaerospace.com
here you will see the missile launch. what i want to work is on the `Missile control system and ballast stability``

thank you very much.
 
Last edited:
  • #6
Are you designing a weapon to attack the USA?

The reference you provided says that the missile is underwater only 2 seconds after launch.

Inertia will be an important factor, perhaps the dominant factor. You need a dynamic model, including the spatial distribution of buoyancy, and including the hydrodynamics of the water passing over the outside shell at a pretty good speed. That is not simple. The data you need from real missiles is probably classified.

Do you have access to the missile data and dynamic computer models?
 
  • #7
Haha, No access to any data. just working on a university project.
 
  • #8
Zahid said:
yes, you are right but what i m working on is totally different thing, have you heard about sea dragon or seabee or if you could visit to www.rippleaerospace.com
here you will see the missile launch. what i want to work is on the `Missile control system and ballast stability``
I only read a little at the link. Why do they use that technique to launch the missile? It seems like it would be much easier to just launch it from a small boat that is towed by the ship. What advantage is there to having it in the water held upright by a ballast before launch?
 
  • #9
berkeman said:
I only read a little at the link. Why do they use that technique to launch the missile? It seems like it would be much easier to just launch it from a small boat that is towed by the ship. What advantage is there to having it in the water held upright by a ballast before launch?

That's a question for a sailor.:wink:

For many consecutive days, seas can be too rough to have a rocket free standing vertically without toppling and /or spoiling the launch angle.

If you bolt it to the deck, it could capsize the boat because the c.g. is too high.
 
  • #10
Zahid said:
Haha, No access to any data. just working on a university project.

If you have no data, then make a computer model and run a range of cases covering a range of assumptions about ballast distribution.

With only 2 seconds underwater, even an unstable ballast distribution may not tip enough to ruin the launch. It takes time to tip.
 
  • #11
its not important that i have to do all what is in that website, but that is just an example.
 
  • #12
my focus area is `Dynamics of Missile ballast`, not the whole System.
 
  • #13
It appears that they intend for the rocket to be buoyant for towing to the launch site and if it is to be towed then the longitudinal buoyancy cg must be in the center of the rocket length so they require a ballast to hold it vertical for launch.

At the same time I have rarely seen so much technobabble to promote a concept that is not very different from the method used for launching rockets and ICBM's from submarines, where the rockets are ejected vertically from the submarines before firing.
 
  • Like
Likes Zahid
  • #14
can anybody help me? I am in critical condition
 
  • #15
Zahid said:
can anybody help me? I am in critical condition

Help you how?
 
  • #17
the rocket is layed in th water, we fill the ballast with water to upheld(stand) the rocket.
Rocket Specifications:
Length: 7m
Weight: 602 kg
Diameter: 0.52 m
the length of the ballast is 2m
the rocket is two stage rocket.
the Ballast have 5 chambers for water to fill in.
how much water is need in the ballast to make the rocket stand?
what is rocket stability calculations during standing and launch?
how much pressure is released during the launch?
and other specification related to the dynamics of the ballast system
thank you in advance, anybody can give detail.
 
  • #18
You don't expect us to do the whole project for you, do you?

Please show us what calculations you have done so far.
 
  • #19
i have completed the theory part
now need to work on the calculations, also did design and simulations.
but not yet how to calculate the stability in the water, the behaviour of the surounding(wind and water wave) during tilting an standing( the angle of heel).
 
  • #20
Zahid said:
i have completed the theory part
now need to work on the calculations, also did design and simulations.
but not yet how to calculate the stability in the water, the behaviour of the surounding(wind and water wave) during tilting an standing( the angle of heel).
Show us your work or this schoolwork project thread or it will be closed. Do the work please and show us.
 
Last edited:

1. How does the position of the missile's center of gravity affect its stability?

The center of gravity is the point at which the weight of the missile is evenly distributed. The position of the center of gravity is crucial for stability as it determines how the missile will behave in flight. If the center of gravity is too high or too far back, the missile will be unstable and may tumble or veer off course. On the other hand, if the center of gravity is too low or too far forward, the missile may be less maneuverable and have difficulty changing direction.

2. What is ballast and how does it contribute to missile stability?

Ballast is any material added to the missile to adjust its weight and balance. It is usually placed in the nose or tail of the missile. By adjusting the distribution of weight, ballast helps to control the center of gravity and maintain stability. Ballast can also be used to counteract external forces, such as wind or air resistance, that may affect the missile's flight path.

3. How do engineers determine the optimal amount of ballast for a missile?

The optimal amount of ballast for a missile is determined through extensive testing and computer simulations. Engineers consider factors such as the size and shape of the missile, its intended flight path, and the materials used to construct it. They also take into account potential external forces and the desired level of stability. Through iterative testing and analysis, engineers can determine the ideal amount and placement of ballast for a specific missile.

4. Can the ballast be adjusted during flight to improve stability?

In some cases, ballast can be adjusted during flight to improve stability. This is most commonly seen in guided missiles, which have control surfaces that can move to adjust the missile's orientation. By shifting the position of the ballast, these control surfaces can help to maintain a stable flight path. However, this requires advanced technology and precise control systems, so not all missiles have this capability.

5. Are there any other factors besides ballast that affect missile stability?

Yes, there are several other factors that can affect missile stability besides ballast. These include aerodynamics, propulsion, and control systems. The shape and design of the missile can greatly impact its stability in flight. Additionally, the type of propulsion used, whether it be rockets or jet engines, can also affect stability. Finally, the control systems, such as fins or control surfaces, play a crucial role in maintaining stability by adjusting the missile's orientation and flight path.

Similar threads

How to check the Stability of ANY Truss?
    • Mechanical Engineering
Replies
1
Views
693
Mechanics of a missile liftoff
    • Mechanical Engineering
Replies
2
Views
1K
Calculate the max speed at which a submarine rises/dives
    • Mechanical Engineering
Replies
5
Views
487
NTSB Accident Report, Data Entry Error
    • General Engineering
Replies
14
Views
1K
Ionizing Atmosphere on the nose of a rocket, missile or aircraft to reduce drag
    • Aerospace Engineering
Replies
3
Views
681
I Effects of the centre of gravity on aircraft's stability
    • Other Physics Topics
Replies
4
Views
260
Frequency stabilized solid state lasers for coherent optical communication
    • Electrical Engineering
Replies
1
Views
695
Statics problem -- Stability analysis of a slab resting on an incline
    • Mechanical Engineering
Replies
2
Views
1K
Obtaining stability criterion for 2nd order ODEs in coefficient form
    • Calculus and Beyond Homework Help
Replies
1
Views
275
Why is a beam supported by two cables more stable than one?
    • Mechanical Engineering
Replies
2
Views
957

Hot Threads

Recent Insights

Back
Top