Originally Posted By: paul
Quote:
And yet are completely unable to provide one iota of proof. Strange, isn't it - you're right and yet you've been able to convince no one here...LOL


I see where kallog also agrees that m*VE cannot be ZERO.


he said no such thing - he said it would appear to be non-zero and would wait for my return to explain why I was saying it was zero. And I did just that, in my first post today.

Originally Posted By: paul
and given that us three are the only participants in this
thread , your wrong.

also who have you convinced?


kallog agrees with me that momentum of a closed system is conserved, and thus your engine is impossible. the closest he's been to agreeing with you is on the m*Ve, where his exact statement was "But we'll see better when he returns."

kirbygillis stopped by to make fun of you, which I assume means (s)he disagrees with you

So all three who've bothered to post vis-a-vis your claims agree that basic physics makes your engine impossible. None were not willing to take your claims vis-a-vis at face value...

Originally Posted By: paul
the speed of sound is a constant it is the speed at which SOUND travels in air , not the speed limit that air can travel at.


Actually, the speed of sound is neither a constant, nor is it just the "speed that sound can travel at". The speed of sound varies with the physical makeup of the medium and its temperature. Different mixtures of gasses will have different speeds of sound - for example, the speed of sound in air is highly dependent on the amount of water vapor present. its also dependent on temperature.

The speed of sound is also the maximum speed that a gas can flow at under its own pressure. The speed of sound is determined by a gasses elastic modulus. That same elastic modulus also defines the back pressure of a flowing gas, and thus the degree to which a gas can accelerate itself due to its own pressure.

In simple terms, as a gas accelerates itself it also creates backpressure - resistance to flow generated by the elastic qualities of the gas itself. Gas can only accelerate itself, by its own pressure, to a point where the backpressure equals the gas pressure. Ignoring friction, backpressure will equal gas pressure when the speed of that gas is equal to its speed of sound.

You can get a gas to flow faster than its speed of sound, if you provide it with a either a source of energy other than its own pressure, or with reduced back-pressure. In the case of a nozzle you get the latter; a lowering of back pressure due to expansion of the gas stream.

Originally Posted By: paul
not once have you even tried to calculate or give the exact speed or velocity.


Oh, but I have, several times:

Speed of gasses leaving the tube: speed of sound (assuming room temp air, no humidity, approx 343m/s)

Additional speed of gasses due to acceleration by nozzle (Ve): 0m/s

Originally Posted By: paul
and if you did you just simply stated that it was ZERO.


Another lie - the only thing I stated was zero was Ve. And I provided both the formula and math to show that was the case.

Originally Posted By: paul
I calculated the velocity or speed at 313600.466382069 m/s which is 194.86 miles per second.


Which is wrong - the gas is choked at ~343m/s. Even your own sources described that - maybe you should read your own links...

Originally Posted By: paul
Quote:
Nope. And once again the irony - both the page I linked to, as well as the one you linked to, clearly state how nozzles help provide additional thrust. Apparently you don't even read your own sources.


provide additional thrust , as in the .37N

but you want to neglect the 45N comming from m*Ve


I ignore nothing; you're the one ignoring how those numbers are calculated.

m*Ve produces ZERO newtons of thrust when there is no divergence in the nozzle, as outlined numerous times before. [Pt-Pe]Ae produces the same amount of thrust, regardless of the nozzle design.

Originally Posted By: paul

I have a great idea , can you find an article that tells
how the nozzle itself produces more thrust than the
pressure that is either stored as in the air tank or the pressure that is produced by a jet engine or rocket engine.


It was provided to you two or three pages ago:
http://www.nakka-rocketry.net/th_nozz.html
http://www.nakka-rocketry.net/th_thrst.html

That is written by a fellow named Richard Nakka, a proverbial god in the EX rocketry community for the better part of two decades. On his webpage you'll find everything from basic theory, to engine design, to propellant formulation, to ready-to-go engine designs. He has calculators, applets, and various examples to illustrate every aspect of rocket engines you can imagine.

The relevant quote, in regards to the speed of sound, is:
"The critical point where the flow is at sonic velocity (M=1 at A/A*=1) is seen to exist at the throat of the nozzle. This shows the importance of the nozzle having a diverging section -- without it, the flow could never be greater than sonic velocity!"


Note: underlining provided by me, rest is original.

As for the amount of thrust added by the nozzle:
"The Thrust Coefficient determines the amplification of thrust due to gas expansion in the nozzle as compared to the thrust that would be exerted if the chamber pressure acted over the throat area only . . . The slope of the curve is very steep initially, then begins to flatten out beyond Po/Pe = 5. This is significant, as it indicates that even a nozzle provided with a minimal expansion will be of significant benefit. With such a pressure ratio of 5, the resulting thrust is about 60% of maximum theoretical"[/u]


And here is an applet, and more theory, describing these various factors:
http://www.engapplets.vt.edu/fluids/CDnozzle/cdinfo.html


Originally Posted By: paul
meanwhile heres a bottle rocket that just uses air pressure...


And? the amount of force derived in the case of the bottle rocket filled only with air will described by [Pe-Po]Ae; so that doesn't exactly help your case any. Water complicates things, due to two-phase flow, which I described earlier.

And you may want to look at the source you got the rocket engine picture from:
http://www.aerospaceweb.org/design/aerospike/nozzles.shtml

Even in this page - as in YOUR OWN SOURCE they counter your claim:
"the ultimate purpose of the nozzle is to expand the gases as efficiently as possible so as to maximize the exit velocity (v exit)"

LOL, disproven by your own sources - must hurt.

Bryan
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