Increasing propulsion(rockets)-newb

  • Thread starter Thread starter imaginia1993
  • Start date Start date
  • Tags Tags
    Increasing
AI Thread Summary
The discussion centers on the efficiency of rocket propulsion and the potential for redirecting exhaust energy to improve velocity. It highlights that a significant portion of energy from combustion is wasted as exhaust, suggesting that if this energy could be redirected, rocket velocity could theoretically double. However, it is clarified that reflecting exhaust would not enhance propulsion since the exhaust has already left the rocket and cannot be redirected. The conversation also touches on Newton's third law and the limitations of creating infinite forces through reflection, emphasizing that mechanical components are necessary for effective propulsion. Overall, the participants express curiosity and a willingness to learn more about rocket science and propulsion systems.
imaginia1993
Messages
2
Reaction score
0
Newb here with a question. correct me if I've got anything wrong(I'm assuming I've got quite a number of errors here, so be patient)
I'm assuming that in a rocket, the energy release in the combustion chamber is directed 2 ways, up and down and the one that provides propulsion is the force acting upwards and the force released downwards is wasted.
in rockets, I have observed that at least half of the total energy released during the
explosion in the combustion chamber is wasted as exhaust fumes which does not contribute to the velocity of the rocket. It is quite obvious, that if this
half of the force can be redirected upwards(meaning all the momentum at every direction is focused only one direction) then the
velocity of the rocket can be increased by a hundred percent. Is it possible to reflect this force upwards to further increase the rockets velocity?

There is also another theory that I'm still not sure about, but here goes. According to Newton's third law, if a force's opposite
equal is reflected to the same direction, and another opposite force of the opposite force is produced during the reflection and is reflected by the
same reflectant(thing which had reflected the first opposite force) and another opposite force is produced and reflected, an
infinite amount of forces can be made. This could mean that one explosion is enough to send a rocket moving for an infinite period.
I'm guessing that there are other laws which would restrict this principle from existing. Still, iis it plausible at all? All in all, both these theories are merely hypothesis and not true unless proven.
Thx for any help at all. I'm just wondering.
 
Physics news on Phys.org
Disclaimer: I am not rocket scientist, so my opinion can be wrong too.

By Newton's 3rd law, the downward force on the exhaust is equal to the upward force on the rocket. Since mechanical power is equal to F X v, the much faster exhaust will waste much more energy than that gained by the rocket. The efficiency of rocket propulsion is very low, much less than 1%. Energy efficiency is not the major concern for rocket design; it is the mass of the fuel. By the conservation of momentum, the total momentum of the exhaust is equal to the momentum gained by the rocket (ignoring drag and Earth gravity). Since the ultimate velocity of the rocket is much faster than the exhaust, the required fuel is a thousand or so times as heavy as the payload.

The exhaust, when leaving the rocket, is entirely downwards, giving the maximum possible upward force on the rocket. After leaving the rocket, the exhaust hits air below so that it spreads out. However, since the exhaust has left the rocket, reflecting it won't have any effect on the rocket.

You can't create forces by simply reflecting. To reflect any object, you need an extra force to do so.
 
I also know little about rocket science.
But i find the subject interesting, as there appears to be much room for improvement.
 
imaginia1993 said:
I have observed that at least half of the total energy released during the
explosion in the combustion chamber is wasted as exhaust fumes which does not contribute to the velocity of the rocket.

Its more than that, following formula of K.E the energy distribution to the gasses will higher as compared to what the rocket gets.

half of the force can be redirected upwards

We need a sort of mechanical component to do that job, actually you need such a thing that distributes the momentum of the gasses to a set of matter, but in the opposite direction and without distributing the momentum to the body itself (if it does distribute, it should be in the direction at which the rocket needs to be propelled.)

then the
velocity of the rocket can be increased by a hundred percent.

We can't achieve 100%...I mean, at most it'll be like a diesel engine, i.e much of the energy will be dissipated in the form of heat...I think it will be 70% at most.

and another opposite force of the opposite force is produced during the reflection and is reflected by the
same reflectant(thing which had reflected the first opposite force) and another opposite force is produced and reflected, an
infinite amount of forces can be made.

:confused:

How can you say that?...actually there're only 2 forces, since Earth won't be there when the rocket takes off, you can ignore that.


aaa...I've made a component to derive the normal reaction from the internal stress of a body, so that might do the job.

Actually its a part of propulsion system that I'm developing.
 
Wow, I didn't expect replies so encouraging(mostly) replies. As I have aforementioned, I'm a real newb, not very old too(considered inferior, a little) so thanks for you peoples corrections. Learnt a lot. Actually, I thought people would think that this idea is nonsensical but thanks for not thinking that way(I hope) Anyway, got another question.-im not really sure where this goes, so please point me in the right category if this is the wrong section(im really lost)
1.What is the difference between force and impulsive force?-both have same unit and identical formula
2.If an object which has an impulsive force, hits an object which is stationary and presumably not easy to move, like a wall, Will the wall also exert an equal opposite impulsive force on the object(normal reaction)? If so, then why is it that the force exerted by the wall cause the object to move in the opposite direction of its initial direction?-from my understanding, the object and the wall exert the same amount of impulsive force which should cancel each other out and the object will be stationary.(do correct me if I am wrong, I think I am)
Last note, dE_logics,do you mind if you explain the system that your developing? It seems awfully interesting, and I'd love to learn. If you don't mind, could you mail me at this address:
imaginia1993@yahoo.com Thx.
Btw, to all the repliers, thanks too and God bless!
 
Deleted.
 
Last edited:
Thread 'Question about pressure of a liquid'
I am looking at pressure in liquids and I am testing my idea. The vertical tube is 100m, the contraption is filled with water. The vertical tube is very thin(maybe 1mm^2 cross section). The area of the base is ~100m^2. Will he top half be launched in the air if suddenly it cracked?- assuming its light enough. I want to test my idea that if I had a thin long ruber tube that I lifted up, then the pressure at "red lines" will be high and that the $force = pressure * area$ would be massive...
I feel it should be solvable we just need to find a perfect pattern, and there will be a general pattern since the forces acting are based on a single function, so..... you can't actually say it is unsolvable right? Cause imaging 3 bodies actually existed somwhere in this universe then nature isn't gonna wait till we predict it! And yea I have checked in many places that tiny changes cause large changes so it becomes chaos........ but still I just can't accept that it is impossible to solve...
Back
Top