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Talk:Tsiolkovsky rocket equation

Applicability
I have a serious beef with the applicability section of this page. The second and third sentences of this paragraph:

>Also, the equation strictly applies only to a theoretical impulsive maneuver, in which the propellant is discharged and delta-v applied instantaneously. Orbital maneuvers involving significantly large delta-v (such as translunar injection) still are under the influence of gravity for the duration of the propellant discharge, which influences the vehicle's velocity. The equation is most accurately applied to relatively small delta-v maneuvers such as those involved in fine-tuning space rendezvous, or mid-course corrections in translunar or interplanetary flights where the gravity field is relatively weak.

The second and third sentences seem to imply that the rocket equation is just not valid for going to the moon, when it should specify that it does not work well with low T/W systems, and works just fine with high T/W systems (like in apollo). Unless, that is, I have a serious misunderstanding. The rocket equation works *just fine* for high-delta-V maneuvers, but not long duration maneuvers. If someone can show a citation proving otherwise I would like to see it. Otherwise I plan to revise that soon. LarsOsborne (talk) 02:51, 12 March 2015 (UTC)

 * I believe your proposed edits are quite correct. I'd say make the changes.  Be bold.  A reference for the low T/W limitation would be nice, but even without a ref, your correction is much better than what is currently there. MattDuchek (talk) 20:55, 25 June 2015 (UTC)

 * Actually, I'd say scrap all the text in that section and just make the distinction about non-applicability to low T/W. Also, non-applicable to launch from planetary surface and landing through atmosphere. MattDuchek (talk) 20:44, 25 June 2015 (UTC)

 * I have made edits to the applicability section to clarify this and other points. Sanchazo (talk) 17:44, 26 June 2015 (UTC)

Derivations
Could please someone change the direction of the vector V_e in the right picture? It contradicts the equation for P_2. Thank you! --193.170.243.211 (talk) 08:17, 24 October 2013 (UTC)

Perhaps we could have more mathematically rigorous derivations for the various formulae? -- The Anome 10:51, 10 Oct 2004 (UTC)

 * I would welcome that. But is this a request or an offer?--Patrick 21:32, 2004 Oct 10 (UTC)

 * The derivation is simple. Force is assumed constant, and a = F/m.  The mass decreases as fuel is consumed, so you are integrating 1/m, which is ln(m).  Tsiolkovsky did this calculation in 1897, according to his notebooks.  DonPMitchell 07:42, 26 August 2006 (UTC)

In the Special Relativity paragraph, where is the given formula taken from? The use of Isp/c does not seem to work properly. It seems to have the wrong units, and in an example I calculated for a rocket with relativistic exhaust at 2/3 c and a small mass of propellant, the given formula produced a nonsensical result. Should it be Effective Exhaust Velocity instead? Would that perhaps be calculated as ve*ExhaustGammaFactor? That method of calculating Effective Exhaust Velocity matches one made from the (Exhaust) Relativistic Momentum given by the Wolfram Alpha Calculator for momentum of 1 gram at 2/3 c YodaWhat (talk) 04:45, 19 June 2012 (UTC)

historical note
The original form of the rocket equation, and the form which is still used in practice, corresponds to the original definition of specific impulse (given as an alternative definition in Wikipedia): m1/m0 = exp(-dv/g/Isp). This has the distinct advantage that Isp is the same in both English and metric units; furthermore, delta-V expressed in various units (e.g., m/s or km/s) can be accommodated by converting g to the same units.

historical note (correction)
On further reflection I am almost certain that Tsiolkovsky's work predates the development of the concept of specific impulse (Isp) by many decades, so the original form of the rocket equation must have used exhaust velocity. But I can state pretty authoritatively that the form generally used today includes g*Isp to replace exhaust velocity, since propellants are almost universally characterized by Isp in seconds (i.e., the alternative definition of specific impulse given in Wikipedia). [note and correction by Ted Sweetser, tsweetser@aol.com]

More concerning Isp
Specific impulse is indeed in seconds. Specific impulse is not equivalent to exaust velocity, so describing Ve as Isp is false. [correction by T.Cooper, the.centipede[at]gmail[dot]com

More about Isp
It's a measure of impulse per mass of fuel consumed. Impulse equals momentum, incidently. The units are often given as "seconds", but it is more accurate to give them as "kgf-sec/kg", kilogram-force seconds per kilogram, or pound seconds per mass-pound. The number is the same in both cases. DonPMitchell 07:40, 26 August 2006 (UTC)

energy gain?
I'm not an expert, so forgive me if I am making a silly question: If at some point in the future we get to make a rocket propulsion system in which the propellant mass is negligible and its potential energy goes entirely to the rocket acceleration itself (so that the percentage of that energy taken by the propellant being expelled is not inversally proportional to its mass), wouldn't we get a kinetic energy gain in the rocket that would increase for the same amount of fuel spent in a given time frame as velocity got higher? If the rocket was at 20.000 m/s, for instance,  and we used a given energy amount to accelerate it to 20.001 m/s, wouldn't we get a greater increase in energy than if we were just accelerating from 100m/s to 101m/s, using the same quantity of fuel? If it is so, couldn't it mean a kinetic energy gain to the rocket greater than the energy contained in the fuel that was spent to obtain it, if we got our rocket at a sufficiently high speed?

 * It's not a silly question, it's a good question, but if you do the maths it turns out that energy is conserved (of course). The reason is that the kinetic energy of the propellant in a rocket going 20,000 is much higher than one going at 100 m/s. So, when emitted by the rocket, the propellant loses much more energy at high speed, than at low speed, and that's why the high speed rocket gains more energy than at low speed. Rockets are actually optimally efficient when the exhaust speed and the speed of the rocket match- in that case 100% of the energy ends up in the rocket and the exhaust just stops dead. Above and below that speed, efficiency drops. Hope this helps.WolfKeeper 22:03, 17 September 2006 (UTC)
 * Speed of the rocket in which frame? Stops dead according to who? 80.6.239.132 (talk) 14:01, 6 March 2012 (UTC)
 * That would be the Center of mass frame/zero momentum frame which is the frame with the lowest total energy and very probably the one you build the rocket in, or at least launch from, and the one you're most interested in (leaving!)Teapeat (talk) 16:32, 6 March 2012 (UTC)
 * How do you build a rocket "in" a reference frame, or launch a rocket "from" a reference frame?" MarcusMaximus (talk) 16:07, 19 June 2012 (UTC)
 * Yep, as Wolfkeeper says, you have to include the rocket plus all propellant (including spent propellant) to get this right. You'll find, of course, that energy and momentum are conserved, since these are the principles from which the rocket equation itself was derived.  As the mass of propellant gets smaller, its velocity becomes correspondingly greater, and so you can never neglect the spent propellant no matter how quickly it exits the rockets.  (Of course there are also relativistic effects to consider.)  --Doradus 02:13, 18 September 2006 (UTC)

Why units?
This edit added units to all the bullet points. The equation is correct regardless of the units used (as long as they are consistent with each other) so I think the units just confuse things. Can we remove them? --Doradus 18:16, 16 September 2007 (UTC)

 * I think they simplify things because they make the objects more concrete; people know that if something is in m/s that it is a speed, or has speed-like properties. Furthermore we are really supposed to be using SI units in the wikipedia, and I see no reason to encourage the use of non SI units.WolfKeeper 00:01, 17 September 2007 (UTC)

 * But if we say it's a speed, we don't need the units to convey that it has speed-like properties, right? And you're the one who added the non-SI units, not me; I'd rather just remove all units.  I think adding units to this kind of equation is an unusual thing to do, looking around at articles like Newton's law of universal gravitation or heat conduction.  A counterexample is ideal gas law, because there's a constant in that equation whose magnitude depends on the units chosen; this is not the case in Tsiolkovsky's equation. --Doradus 15:17, 18 September 2007 (UTC)

Description of delta-v
When thrust is applied in a fixed direction, delta-v is precisely the magnitude of the change in velocity, is it not? I'd like to reinstate this explanation that was removed by this edit if that's ok with everyone. --Doradus 18:18, 16 September 2007 (UTC)

 * Trouble is, the rocket equation still applies when the thrusts are not in the same direction or when gravity is acting. Delta-v is a bit more subtle that that; on balance I decided that having people click if they didn't already know what it was, was probably a good idea.WolfKeeper 00:04, 17 September 2007 (UTC)

 * Ok. I think we address sufficiently that by allowing for "a journey involving multiple such maneuvers".  (However, the current phrasing with "such maneuvers" currently doesn't make any sense, because the context has been deleted.)  I think we lose more by removing the succinct definition than we gain by being completely correct.  Some people (like me) occasionally print out Wikipedia pages to read later, and though I know we're not supposed to cater to this, it seems kind of mean to make the text intentionally terse to encourage people to click the link and read another article.  --Doradus 15:47, 18 September 2007 (UTC)

 * This is only the introduction though, I think having a short introduction is highly desirable. If you want to add other text to expand on delta-v elsewhere, I certainly wouldn't stop you.WolfKeeper 16:39, 18 September 2007 (UTC)

 * Ok. I think I'd still lean toward having at least some kind of summary of delta-V in the intro, but I can see your point.  --Doradus 14:31, 30 September 2007 (UTC)

Kinetic energy of accelerating the reaction mass

 * $$\frac{1}{2}(m_0-m_1)v_e^2$$

 * This is the kinetic energy of accelerating the reaction mass.

This is either vague or contradicting what follows.--Patrick 22:25, 16 September 2007 (UTC)

 * I fixed it.--Patrick (talk) 23:35, 9 January 2010 (UTC)

Moore's "derivation"
I removed (temporarily?) the following excerpt:

"However a recently discovered pamphlet "A Treatise on the Motion of Rockets" by William Moore shows that the earliest known derivation of this kind of equation was in fact in Royal Military Academy at Woolwich in England in 1813, and was used for weapons research."

Because now, when one more link to faximile of Tsiolkovsky's manuscript, explicitly showing that he derived the formula on May 10, 1897, is added, a real supporting evidence to a claim of William Moore's "earlier derivation" should be provided. It's not enough to point to "pages 499-521" of an article in a journal, which is unavailable online and hence is difficult to verify. The place, where William Moore derived this formula in his work should be cited precisely and this citation should be easily verifiable. Until this is done a "claim" of William Moore's superiority is nothing more than weasel words and WP:OR. Cmapm 19:33, 3 October 2007 (UTC)

 * I've undone your edit because there's absolutely no requirement that references be available online.WolfKeeper 22:12, 3 October 2007 (UTC)

It is proper to honor Tsiolkovsky by naming the equation after him, because of the context and conclusions he drew from it: that spaceflight was possible and that it required a new kind of rocket more energetic than the black-powder artillery rockets of his time. That is, it led him to propose the liquid fuel rocket. He did much more than just integrate a = F/M, which any high school calculus student could do. DonPMitchell (talk) 04:19, 12 November 2010 (UTC)

Please explain ALL formula components
I can find no reference to 'ln' in this document that explain what those two characters are representative of. —Preceding unsigned comment added by Battleshield (talk • contribs) 14:40, 30 November 2009 (UTC)

 * ln is natural logarithm.--Patrick (talk) 22:50, 9 January 2010 (UTC)

chutiya ho tum —Preceding unsigned comment added by 117.201.70.175 (talk) 06:36, 19 February 2010 (UTC)

Me too! I just came here to leave a note and find one already here - since 2009! Any chance of putting that explanation in the article? Robotics1 (talk) 12:09, 20 August 2012 (UTC)

derivation
Hallo, I'm wondering, why do you take Ve = V + ve and not Ve = V-ve? Does Ve not have to be zero when the rocket is at speed ve?

Thanks, — Preceding unsigned comment added by 84.192.164.31 (talk) 15:17, 4 June 2011 (UTC)

 * Ditto! I was about to write the same! When the exhaust speed (relative to the rocket) is equal to the rocket speed ($$v_e = V$$), then the speed relative to the observer should be 0, which you only get if $$ V_e = V - v_e$$. I think the derivation is wrong, but I don't really know how to fix it. -- 140.181.115.42 (talk) 12:07, 5 August 2011 (UTC)

 * Got the error! Indeed, the correct form is $$ V_e = V - v_e$$. To get the correct sign in the equation, one has to keep in mind that the mass differential is actually subtracted from the rocket, i.e. that $$dm (propellant) = -dm (rocket)$$. Since we are calculating the change in mass of the rocket, we have to enter the minus sign, and the final expression is correct again. I'll change it in some time, the derivation needs some rephrasing. Of course any other kind person could do it too... :-) - 140.181.115.42 (talk) 16:32, 20 September 2011 (UTC)

Russian cosmism
Please explain the relevance of Russian cosmism before adding it back. I'll be happy to clean up the English if necessary, but only if it is worthy of inclusion in this article. Martijn Meijering (talk) 18:33, 13 August 2011 (UTC)

I see the edit in question has been restored again, without discussing it first. In its present form this change isn't helpful. The claim that the Tsiolkovsky equation only makes sense in the context of Russian cosmism is simply false: aeronautics textbooks tend not to even mention Russian cosmism. The statement about simulacrum is incomprehensible to me. I have no idea what it is supposed to mean. Please observe Wikipedia guidelines and discuss this before making controversial edits. Martijn Meijering (talk) 11:37, 14 August 2011 (UTC)

I looked up simulacrum and it refers to when something is a copy of something else and has a similar image, but is not at all the same, such as an idol of a god. Perhaps Tsiolkovsky is the god of rocketry, but since Moore was first he can hardly be a copy. Also, Moore's military application does not invalidate his work. After all, many rockets still are military. The history of English analysis of rocket propulsion for the military is quite substantial. I suppose in the history section one could mention that Tsiolkovsky's work and derivation of this equation was foundational in astronautics, but I wonder why all the rest of this is in the article.69.231.117.173 (talk) 04:06, 20 August 2011 (UTC)

The rocket equation is named after Tsiolkovsky because he was first to consider the wider problem of spaceflight, whether it was possible to attain orbital velocity with chemical fuel, the necessity of high-energy liquid fuel rockets, etc. It is relevant to note William Moore's work, but not very interesting to bring up Meshersky. The comment about Meshersky doesn't make sense to me, is someone claiming that Tsiolovsky was a follow of him? I've never hear that anywhere. DonPMitchell (talk) 21:31, 25 August 2011 (UTC)

I (temporarily) withdraw my comment. Sorry about that.

Specific impluse (relativistic; dimensional analysis)
In the relativistic case, the power in the form m0/m1 = [(1+deltaV/c)/(1-deltaV/c)]^(c/2Isp) should surely be dimensionless.

From the definition give of Isp in the introduction, Isp = ve/g0, so has time units (indeed "expressed as a time period"); but then c/2Isp is not dimensionless (it distance/time^2).

Can someone explain what I'm missing? Ridcully Jack (talk) 20:42, 16 September 2012 (UTC)

 * I suspect the formulas are in error (That's why I came to the talk page). I think the relativistic versions of the equation are using Isp when they should be using Ve. Think about it, where would we have gotten a "multiply by little g" step in there? If you substitute the velocity Ve instead of the time unit Isp, the units work out. — Preceding unsigned comment added by Sephalon1 (talk • contribs) 04:38, 1 October 2012 (UTC)

 * That's what I thought too, but I've forgotten too much physics to edit this page. Ridcully Jack (talk) 07:19, 1 October 2012 (UTC)

"Incorrect derivation"?
The final section contains these words:

"Using this formula with $$m(t)$$ as the varying mass of the rocket is mathematically equivalent to the derived Tsiolkovsky rocket equation, but this derivation is not correct.

A simple counter example is to consider a rocket travelling with a constant velocity $$v$$ with two maneuvering thrusters pointing out on either side, with both firing such that their forces cancel each other out. In such a case the rocket would be losing mass and an incorrect application of $$F = dp/dt$$ would result in a non-zero but non-accelerating force, leading to nonsensical answers."

The second paragraph is a nonsense. Momentum is a vector quantity, as is velocity, so it's perfectly plain that there is zero net force on the rocket. Is there any merit to the above or should it be deleted? 131.111.184.8 (talk) 12:49, 7 October 2012 (UTC)

 * I agree. The counter example puts rocket's velocity in the place of v. Why wouldn't there be the vrel which is, in this case, zero? For me it's hard to see why one must not use Newton's general second law (F = dp/dt) to solve variable-mass problems but instead one should use "same-looking" formulas which are derived using the same general NII and momentum (in an unnecessarily complicated way) only to get there the essential subscripts like vrelative and Fext and Fnet. Where's my blind spot? What's the difference? I'd like to keep it simple and use only F = dp/dt = vdm(t)/dt + mdv(t)/dt. I see no contradiction there. What this simple equation gives, for example, when there are no external forces (F=0) and mass is losed with constant relative velocity v? --- It gives a result similar to Tsiolkovsky's (write: -vrel * (1/m) * dm = dv => integrate over time => get Tsiolkovsky). Oulal (talk) 13:04, 24 October 2012 (UTC)
 * Yes, there is merit to the paragraph and no, it should not be deleted. Set up coordinates so that the rocket travels with constant velocity vx along the x-axis, and so that its thrusters are ejecting mass in the +y and –y directions. Now take the equation
 * $$ \mathbf{F} = m\frac{d\mathbf{v}}{dt} + \mathbf{v}\frac{dm}{dt}$$
 * and examine its x component:
 * $$ F_x = m\frac{dv_x}{dt} + v_x\frac{dm}{dt}.$$
 * Since the velocity vx is constant, this reduces to
 * $$ F_x = v_x \frac{dm}{dt}.$$
 * Now, since vx and dm/dt are both nonzero, this equation says that there is a nonzero force in the x direction. Hence, the rocket is accelerating, which contradicts the assumption that the velocity is constant. So you are forced to accept one of the two statements: (1) a rocket which ejects mass in some direction (the y direction, in this case) must experience acceleration in a different direction (the x axis, in this case), or (2) the formula F = m dv/dt + v dm/dt is incorrect. My money is on the second of these. Zueignung (talk) 22:22, 23 November 2012 (UTC)

 * Your counterexample is confused. If the mass to be emitted in the +/- y direction is to have no x momentum component in the original frame, it has to be given a push in the -x direction by the moving rocket, which means it will accelerate.  — Preceding unsigned comment added by 217.162.141.172 (talk) 17:13, 20 December 2012 (UTC)
 * You are correct, I removed the section — Preceding unsigned comment added by 192.5.110.4 (talk) 05:56, 24 February 2013 (UTC)
 * No, it is you who is confused. If you attempt to use this putative variable-mass form of Newton's second law to compute the trajectory of the rocket, you do not get to say anything about what the ejected gas is doing (notice that I made no claim about the momentum of the ejected gas; I only indicated the orientation of the thrusters). This putative variable-mass equation is a relationship between the force on the rocket, the mass of the rocket, the velocity of the rocket, and nothing else. Notice that neither the mass nor the velocity of the ejecta occurs anywhere in the equation. As soon as you attempt to discuss the behavior of the ejecta, you no longer get to claim that you're applying Newton's second law to a variable-mass system. Every "derivation" of the Tsiolkovsky equation that uses this putative variable-mass second law ends up cheating somewhere, often by surreptitiously swapping the rocket velocity v for the ejecta velocity vex, by claiming mvex is the force exerted by the ejecta on the rocket (which it isn't), or by invoking the correct, constant-mass second law (i.e., a bait-and-switch). You are invited to read the discussion in Kleppner and Kolenkow's mechanics book or Halliday and Resnick's introductory physics book, or else to look at the relevant sections on the pages variable-mass system (which is even linked multiple times the deleted paragraph, for Christ's sake), Newton's laws of motion and Momentum. I've reinserted the paragraph and added a number of references which demonstrate the incorrect nature of the putative variable-mass second law. Zueignung (talk) 15:57, 2 April 2013 (UTC)
 * In your example, the momentum of the ejecta is given, it just happens to be zero. The force on the rocket is mdotvex. In your example mdot in the positive x direction equals mdot in the negative direction, so the x vector of mdotvex must be 0. In the sources you cite, they specifically state that for a closed system, newtons second law holds. In this case, it is a closed system because the propellant is being counted. — Preceding unsigned comment added by 192.5.110.4 (talk) 07:38, 3 April 2013 (UTC)
 * changed so that it was clear that the derivation is only invalid when the control area is taken as the rocket alone. — Preceding unsigned comment added by 192.5.110.4 (talk) 07:47, 3 April 2013 (UTC)
 * In my example, the momentum of the ejecta is not considered, which is precisely why I'm able to arrive at a nonsensical answer as to the motion of the rocket. People in this discussion have been claiming the exact opposite; i.e., that one can ignore the behavior of the ejecta and still get the Tsiolkovsky equation by applying Newton's second law to a variable mass system. I'm glad that you're able to insert a $$\dot{m}v_\mathrm{ex}$$ term to make the derivation correct, but the point is that people on this talk page have been claiming that one can get the Tsiolkovsky equation without including such a term to account for the momentum of the ejecta (see Oulal's comment, for example). The central question that is being discussed here is Does the equation F = m dv/dt + v dm/dt correctly describe the motion of a rocket of mass m(t) and velocity v(t)?, and the answer is No. The "common misconceptions" section exists to bang the reader over the head with the fact that you must always include the momentum of the ejecta, or, equivalently, you must never attempt to use Newton's second law on a variable-mass system (or a variable-mass "control area", as you call it). Zueignung (talk) 16:20, 3 April 2013 (UTC)
 * The section claims one is dealing with the "relativistic force equation". Relativity is the physics of going fast.  For relativistic forces, one changed from a derivative with respect to time to one where there is a change with respect to the interval tau.  The equation shown is a direct application of the product rule of calculus.  That rule is never wrong as one can do a formal proof that the product rule is true.  It cannot be applied in this case because there are 2 velocities, not one.  Like an earlier commenter, I think pointing out there is not just one velocity makes this issue on confusion less confusing.  I am not going to edit the page myself since I don't like to actively engage in wikipedia issues. Dougsweetser (talk) 12:02, 11 May 2013 (UTC)

Upon reviewing John Taylor's derivation in Classical Mechanics, it appears that deriving this equation from NII may only work coincidentally. But I'm not convinced it's pure coincidence, and I think you'd need a formal proof to prove otherwise. Malnu (talk) — Preceding undated comment added 16:37, 19 April 2024 (UTC)

Example section contradicts Applicability
Since this equation neglects non-rocket forces (aerodynamic and gravity), it cannot be used to accurately calculate mass ratio required for a launch vehicle, without pulling "equivalent" delta v estimates out of the air (or somewhere else.) Therefore, I think the two examples listed (single-stage-to-orbit and two-stage-to-orbit) are really poor ones to use. I think a single example, such as a translunar injection, would be better. JustinTime55 (talk) 18:22, 15 March 2013 (UTC)
 * Using "equivalent delta-v" is the standard practice I believe. Martijn Meijering (talk) 18:26, 15 March 2013 (UTC)

 * While I agree the examples might not be the best, they are not contradictory to the rest of the article. The 9700m/s stated in the example assumes almost 2000m/s of gravity and drag losses, and is used as a general benchmark for launch vehicles that need to reach LEO.  I don't see how it matters (as far as an example of how to use the equation goes) whether we propose a hypothetical 9700m/s launcher or a 9700m/s hohmann transfer. I've changed the example to reflect the assumption of drag and gravity losses. Arthree (talk) 19:57, 21 October 2013 (UTC)

 * I believe the examples do contradict the applicability section, because that section specifically states that the equation is not applicable to launch from a planet with an atmosphere. I do understand that it is standard practice to use delta-v allocations for drag and gravity losses, but there is nevertheless a contradiction here.  Perhaps the problem is that the equation is applicable to launch from a planet even with an atmosphere.  In fact, it is applicable; you just need additional delta-V in your rocket to overcome atmospheric drag than would be implied based on the orbital velocity that you are trying to reach.  I think a re-write of applicability is needed. Sanchazo (talk) 22:55, 25 June 2015 (UTC)

 * I made edits to correct the discrepancy. Please discuss if you disagree. Sanchazo (talk) 17:46, 26 June 2015 (UTC)

Applicability half-section way off topic
The last two paragraphs seem to be out of scope here:
 * The Saturn V rocket used in the Apollo space program is an example of a large, serially staged rocket. The Space Shuttle is an example of parallel staging, where all of its engines are ignited on the ground and some (the solid rocket boosters) are jettisoned to lose weight before reaching orbit.

 * The ion thruster is an example of a high exhaust velocity rocket. Instead of storing energy in the propellant itself as in a chemical rocket, ion and other electric rockets separate energy storage from the reaction (propellant) mass storage. Not only does this allow very large (and in principle unlimited) amounts of energy to be applied to small amounts of ejected mass to achieve very high exhaust velocities, but energy sources far more compact than chemical propellants can be used, such as nuclear reactors. In the inner solar system solar power can be used, entirely eliminating the need for a large internal primary energy storage system.

This article isn't about multistage rockets, ion thrusters, nuclear reactors, or solar-powered spaceflight. JustinTime55 (talk) 18:32, 15 March 2013 (UTC)

 * This is the FUNDAMENTAL equation underlying rocket propulsion. It doesn't matter how you're shedding mass. As long as you're chucking part of your own "machine" backwards, in order to go forwards, this equation applies. Ion engines do that. Solar Electric Propulsion does that. Nuclear reactors that heat up some reactant mass (or even a lump of fissile material that has a lot of shielding in front, and none at the back, allowing fast neutrons to escape) do that. Heck, FARTING would do that. It might seem that solar sails use a 'different' principle, but you could use the relativistic forms of the Tsiolkovsky equation. Treat the absorption of photon as an elastic collision resulting in a 'fuelling' of your sail. The subsequent emission of the photon (these things have finite time-scales you know) is an 'exhaust'. Voila. The terror of Tsiolkovsky lives.

 * Having a list of different propulsion methods which employ this is extremely relevant, because of the seemingly diverse nature of excitatory phenomenon, which all boil down, in the end to the same physical action. Having said that, there is tether propulsion (though I'm not entirely certain that what I did with solar sails - in terms of forcing a mass throw to appear in an explanation - is implausible), and the warp drive (when we finally learn to manipulate space-time itself in that manner) - but the fact that there's only ONE current method that is "not governed" by the Tsiolkovsky equation should add credence to the presence of a list of propulsion methods. 220.224.246.97 (talk) 21:04, 14 July 2013 (UTC)

Discussion on misconceptions
I do not understand why there is a need to have the misconception section. Newton's second law does work for all classical mechanical systems. The original statement of Newton's second law is the force applied is directly proportional to the rate of change of quantity of motion. Back in Newton's time, there was no concept or word for momentum. In modern terms, we write force as rate of change of momentum. So, on expanding the derivative, we get velocity multiplied by rate of change of mass plus mass multiplied by rate of change of velocity. Now, since we usually look at constant mass system, we have rate of change of mass equal to zero. That is why we normally write F = ma. But, force is rate of change of momentum, not mass times acceleration.

What is written about relativity is true. Obviously, we need to consider the rate of change in mass term of force in a relativistic frame because the mass does change with the velocity of the frame. So, the complete form of the Newton's second law always works. Therefore, there needs to be a correction/deletion of this section of the article. — Preceding unsigned comment added by 117.200.127.20 (talk) 12:02, 2 October 2014 (UTC)

 * Have you read any of the three footnotes given in the "misconceptions" section (particularly the Plastino/Muzzio paper)? Could you please point out exactly where their analysis is incorrect? Then, could you please provide a similarly detailed reference which demonstrates that the "complete form of the Newton's second law" correctly handles ablation/accretion systems? After this, we can do as you wish and "correct/delete" the misconceptions section. Zueignung (talk) 15:48, 2 October 2014 (UTC)

So it's wrong to apply Newton's second law to the rocket equation? It's wrong to apply many other things to it. I don't see any evidence it's a common misconception, or a common source of confusion, in any of the sources. The article should describe the right way to do it. A common misconception should be genuinely common, i.e. something many people think of when they consider the topic. An example is centrifugal force, which is commonly misunderstood or misused. But I don't see any evidence of this being anything like that.-- JohnBlackburne wordsdeeds 06:35, 2 November 2014 (UTC)
 * I don't think the section should be removed as it appears to be well-sourced. Maybe the wording needs to be improved. Having a look at variable mass system might help. Martijn Meijering (talk) 16:46, 2 November 2014 (UTC)

 * I can see the point that perhaps this may not be a "common misconception", just a plain old misconception. We could just keep the first sentence (i.e., that you can't derive the Tsiolkovsky equation by setting F = 0 and then using the product rule on Newton's second law). Zueignung (talk) 17:55, 2 November 2014 (UTC)

 * None of the sources though refer to it as a misconception, at least not in the quotes given. It just says you can't do it this way. Fine, the article shows the correct way, including how to use Newton's 2nd Law. We don't need to catalogue or even mention wrong methods, of which there are far too many to mention, unless they are especially notable. If sources remarked that this was a common misconception then it might be worth including. As it is though its some editors judgement and so original research and doesn't belong.-- JohnBlackburne wordsdeeds 04:24, 3 November 2014 (UTC)
 * It does look like a common misconception to me, but I see no great need to state that explicitly or to have a separate section. I think we should say something like "because the rocket is a variable mass system, we need to use the following form of Newton's second law" somewhere at the top of the derivation section. Of course, you then end up with something that's almosty identical to what you'd get if you applied Newton's law naively. It looks as if the sources we're citing now were copied from the other article, so we wouldn't lose any information this way. Martijn Meijering (talk) 11:53, 3 November 2014 (UTC)

(Yes, i'm editing a year-old talk section.) Seems to me like the first sentence of that section could simply be moved to the top of the derivation section with no mention of misconception or confusion, since we follow immediately with the correct derivation. The part about relativity remains unsourced. Unless that is also a common misconception, it seems wholly irrelevant. Someguy1221 (talk) 04:37, 21 August 2015 (UTC)

Bad Graph
Correct me if I'm wrong but shouldn't the graph at the top of the article be Change in Velocity as a function of the Mass Ratio, since the Mass ratio is the dependent variable in most practical cases. Also the scale of the graph is misleading since they are not scaled the same as well as the axis could be labeled much more clearly with units and what part of the equation it's referring back to. I suggest that a graph more like the one I provide in the link would make it much clearer to readers of the article. http://www.maththoughts.com/wp-content/uploads/2014/03/Graph.png — Preceding unsigned comment added by 96.52.51.67 (talk) 04:37, 21 October 2014 (UTC)

william leitch
The Victorian Era Minister William Leitch also independently derived many of the principles of rocket flight.

it's worth making a footnote to the article here

http://www.cgpublishing.com/prime/bookpages/9781926837369.html

--Patbahn (talk) 02:48, 13 October 2016 (UTC)

Casimir Erasme Coquillart
The belgian general Casimir Erasme Coquillart also derived the rocket equation in 1873, according to:
 * Malcolm Macdonald, Viorel Badescu, The International Handbook of Space Technology, Springer, 2014, p. 2.

(accessible via Google.books). --Harlock81 (talk) 11:11, 13 November 2016 (UTC)

Accessibility
What exactly are we trying to tell visitors to this article? What is the mission statement of what we want to communicate to people? What legacy is this article meant to leave for the human race? Consider re-reading this article from a fresh perspective or ask for a friend's point of view to gauge if the article at present is really as accessible as would be rational. 32.209.67.97 (talk) 15:25, 2 July 2017 (UTC)

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Delta V
"It is a scalar that has the units of speed. As used in this context, it is not the same as the physical change in velocity of the vehicle."

Two parts:

I've never seen it written this way... "units of speed", it is speed. I'd recommend changing this to something like, "Its SI units are m/s". In the same vein a lot of these articles are sloppy with notation, sometimes bolding v when standardly that would be reserved for a velocity vector.

Second part:

When used in what context? In the context of the rocket equation? No, it's exactly the physical change in the velocity of the vehicle. Simply because the equation fails to consider other forces that might be acting on your rocket, or silly things you might do, or engineering designs don't change that. It's my opinion that this caveat needs to be more explicit or done away with entirely. Halleffect (talk) 05:03, 20 December 2020 (UTC)

title: Talk:Tsiolkovsky rocket equation


text:
User:Chrismcevoy

Chris McEvoy

I was born in Bath in 1965.

My main area of interest is Usability and Mutuality.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User:Chrismcevoy


text:
M134 Minigun

The M134 Minigun is an American 7.62×51mm NATO six-barrel rotary machine gun with a high rate of fire (2,000 to 6,000 rounds per minute). It features a Gatling-style rotating barrel assembly with an external power source, normally an electric motor. The "Mini" in the name is in comparison to larger-caliber designs that use a rotary barrel design, such as General Electric's earlier 20 mm M61 Vulcan, and "gun" for the use of rifle ammunition as opposed to autocannon shells.

"Minigun" refers to a specific model of weapon that General Electric originally produced, but the term "minigun" has popularly come to refer to any externally powered rotary gun of rifle caliber. The term is sometimes used loosely to refer to guns of similar rates of fire and configuration, regardless of power source and caliber.

The Minigun is used by several branches of the U.S. military. Versions are designated M134 and XM196 by the United States Army, and GAU-2/A and GAU-17/A by the U.S. Air Force and U.S. Navy.

Background: electrically driven Gatling gun
The ancestor to the modern minigun was a hand cranked mechanical device invented in the 1860s by Richard Jordan Gatling. He later replaced the hand-cranked mechanism of a rifle-caliber Gatling gun with an electric motor, a relatively new invention at the time. Even after Gatling slowed the mechanism, the new electrically powered Gatling gun had a theoretical rate of fire of 3,000 rounds per minute, roughly three times the rate of a typical modern, single-barreled machine gun. Gatling's design received U.S. Patent #502,185 on July 25, 1893. Despite his improvements, the Gatling gun fell into disuse after cheaper, lighter-weight, recoil and gas operated machine guns were invented; Gatling himself went bankrupt for a period.

During World War I, several German companies were working on externally powered guns for use in aircraft. One of these designs was the Fokker-Leimberger, an externally powered 12-barrel rotary gun using the 7.92×57mm Mauser round; it was claimed to be capable of firing over 7,000 rpm, but suffered from frequent cartridge-case ruptures due to its "nutcracker" rotary split-breech design, which is different to that of conventional rotary gun designs. None of these German guns went into production during the war, although a competing Siemens prototype (possibly using a different action), which was tried on the Western Front, scored a victory in aerial combat. The British also experimented with this type of split-breech during the 1950s, but they were also unsuccessful.

Minigun: 1960s–Vietnam
In the 1960s, the United States Armed Forces began exploring modern variants of the electrically powered, rotating barrel Gatling-style weapons for use in the Vietnam War. American forces in the Vietnam War, which used helicopters as one of the primary means of transporting soldiers and equipment through the dense jungle, found that their helicopters were vulnerable to small arms fire and rocket-propelled grenade (RPG) attacks when they slowed to land. Although helicopters had mounted single-barrel machine guns, using them to repel attackers hidden in the dense jungle foliage often led to overheated barrels or cartridge jams.

To develop a more reliable weapon with a higher rate of fire, General Electric designers scaled down the rotary-barrel 20 mm M61 Vulcan cannon for 7.62×51mm NATO ammunition. The resulting weapon, designated M134 and known as the "Minigun", could fire up to 6,000 rounds per minute without overheating. The gun has a variable (i.e. selectable) rate of fire, specified to fire at rates of up to 6,000 rpm with most applications set at rates between 3,000 and 4,000 rounds per minute.

The Minigun was mounted on Hughes OH-6 Cayuse and Bell OH-58 Kiowa side pods; in the turret and on pylon pods of Bell AH-1 Cobra attack helicopters; and on door, pylon and pod mounts on Bell UH-1 Iroquois transport helicopters. Several larger aircraft were outfitted with miniguns specifically for close air support: the Cessna A-37 Dragonfly with an internal gun and with pods on wing hardpoints; and the Douglas A-1 Skyraider, also with pods on wing hardpoints. Other famous gunship airplanes are the Douglas AC-47 Spooky, the Fairchild AC-119, and the Lockheed AC-130.

Dillon Aero minigun
The U.S. government had procured some 10,000 Miniguns during the Vietnam War. Around 1990, Dillon Aero acquired a large number of Miniguns and spares from "a foreign user". The guns kept failing to shoot continuously, revealing that they were actually worn-out weapons. The company decided to fix the problems encountered, rather than simply putting the guns into storage. Fixing failure problems ended up improving the Minigun's overall design. Word of Dillon's efforts to improve the Minigun reached the 160th SOAR, and the company was invited to Fort Campbell, Kentucky, to demonstrate its products. A delinker, used to separate cartridges from ammunition belts and feed them into the gun housing, and other parts were tested on Campbell's ranges. The 160th SOAR were impressed by the delinker's performance and began ordering them by 1997. This prompted Dillon to improve other design aspects including the bolt, housing and barrel. Between 1997 and 2001, Dillon Aero was producing 25–30 products a year. In 2001, it was working on a new bolt design that increased performance and service life. By 2002, virtually every component of the minigun had been improved, so Dillon began producing complete weapons with improved components. The guns were purchased quickly by the 160th SOAR as its standardized weapon system. The gun then went through the Army's formal procurement system approval process, and in 2003 the Dillon Aero minigun was certified and designated M134D. Once the Dillon Aero system was approved for general military service, Dillon Aero GAU-17s entered Marine Corps service and were well received in replacing the GE GAU-17s serving on Marine UH-1s.

The core of the M134D was a steel housing and rotor. To focus on weight reduction, a titanium housing and rotor were introduced, creating the M134D-T which had reduced weight from 62 lb to 41 lb. The gun housing had a 500,000-round lifespan before it wore out, which was far higher than a conventional machine gun's 40,000-round lifespan but lower than that of other rotary guns. A hybrid of the two weapons resulted in the M134D-H, which had a steel housing and titanium rotor. It was cheaper with the steel component and only 1 lb heavier than the M134D-T, and restored its lifespan to 1.5 million rounds. The M134D-H is currently in use on various 160th Regiment platforms.

Dillon also created specialized mounts and ammunition-handling systems. Initially, mounts were made only for aviation systems. Then from 2003 to 2005, the Navy began mounting Dillon miniguns on specialized small boats. In 2005, the Naval Surface Warfare Center Crane Division procured guns to mount on Humvees. In Iraq, US Army Special Forces units on the ground were frequently engaged by opposition forces, so they mounted M134D miniguns on their vehicles for additional firepower. After several engagements the attackers seemed to avoid vehicles with miniguns. Later, the Special Forces units began concealing their weapons so opposition troops would not know they were facing the weapon; the regular Army units did the opposite, creating minigun mock-ups out of painted PVC pipes tied together to resemble barrels to intimidate enemies.

Garwood Industries minigun
Garwood Industries created the M134G version with several modifications to the original GE system. The optimum rate of fire was determined by Garwood to be around 3,200 rounds per minute (rpm). The M134G is being produced with this firing rate as well as 4,000 rpm and the previous standard 3,000 rpm rate. Garwood Industries made several other modifications to the 1960s Minigun design in order to meet modern-day military and ISO standards. This includes modifications to the drive motor, feeder and barrel clutch assembly.

From 2015 to 2017 Garwood Industries CEO Tracy Garwood collaborated with firearms dealer Michael Fox and weapons smuggler Tyler Carlson to supply miniguns to Mexican drug cartels. Garwood submitted false paperwork to the ATF claiming that some M134G rotor housings had been destroyed when they were actually sold to the gun-running ring. In 2017 federal agents raided Fox's home and recovered two of the rotor housings that Garwood had reported destroyed. A number of the rotor housings were shipped to Mexico and a completed M134G using a reportedly destroyed rotor housing was recovered from a cartel by Mexican law enforcement. Garwood claimed he did not know that the intended buyers were Mexican cartels although he was aware that they were to be used for illegal activity.

Design and variants

The basic minigun is a six-barrel, air-cooled, and electrically driven rotary machine gun. The electric drive rotates the weapon within its housing, with a rotating firing pin assembly and rotary chamber. The minigun's multi-barrel design helps prevent overheating, but also serves other functions. Multiple barrels allow for a greater capacity for a high firing rate, since the serial process of firing, extraction, and loading is taking place in all barrels simultaneously. Thus, as one barrel fires, two others are in different stages of shell extraction and another three are being loaded. The minigun is composed of multiple closed-bolt rifle barrels arranged in a circular housing. The barrels are rotated by an external power source, usually electric, pneumatic, or hydraulic. Other rotating-barrel cannons are powered by the gas pressure or recoil energy of fired cartridges. A gas-operated variant, designated XM133, was also developed.

While the weapon can feed from linked ammunition, it requires a delinking feeder to strip the links as the rounds are fed into the chambers. The original feeder unit was designated MAU-56/A, but has since been replaced by an improved MAU-201/A unit.

The General Electric minigun is used in several branches of the U.S. military, under a number of designations. The basic fixed armament version was given the designation M134 by the United States Army, while the same weapon was designated GAU-2/A (on a fixed mount) and GAU-17/A (flexible mount) by the United States Air Force (USAF) and United States Navy (USN). The USAF minigun variant has three versions, while the US Army weapon appears to have incorporated several improvements without a change in designation. The M134D is an improved version of the M134 designed and manufactured by Dillon Aero, while Garwood Industries manufactures the M134G variant. Available sources show a relation between both M134 and GAU-2/A and M134 and GAU-2B/A. A separate variant, designated XM196, with an added ejection sprocket was developed specifically for the XM53 Armament Subsystem on the Lockheed AH-56 Cheyenne helicopter.

Another variant was developed by the USAF specifically for flexible installations, beginning primarily with the Bell UH-1N Twin Huey helicopter, as the GAU-17/A. Produced by General Dynamics, this version has a slotted flash hider. The primary end users of the GAU-17/A have been the USN and the United States Marine Corps (USMC), which mount the gun as defensive armament on a number of helicopters and surface ships. GAU-17/As from helicopters were rushed into service for ships on pintle mountings taken from Mk16 20 mm guns for anti-swarm protection in the Gulf ahead of the 2003 Iraq War - 59 systems were installed in 30 days. The GAU-17/A is designated Mk 44 in the machine gun series and is generally known as the Mk 44 when installed on British warships.

The weapon is part of both the A/A49E-11 armament system on the UH-1N; and of the A/A49E-13 armament subsystem on the USAF Sikorsky HH-60H Pave Hawk helicopter. The weapons on these systems feature a selectable fire rate of either 2,000 or 4,000 rpm. There is mention of a possible GAUSE-17 designation (GAU-Shipboard Equipment-17), in reference to the system when mounted on surface ships, though this would not follow the official ASETDS designation system's format.

Gun pods and other mounting systems

One of the first applications of the weapon was in aircraft armament pods. These gun pods were used by a wide variety of fixed- and rotary-wing aircraft mainly during the Vietnam War, remaining in inventory for a period afterward. The standard pod, designated SUU-11/A by the Air Force and M18 by the U.S. Army, was a relatively simple unit, completely self-contained, with a 1,500-round magazine directly feeding delinked ammunition into the weapon. This means the Minigun fitted to the pod does not require the standard MAU-56/A delinking feeder unit. A number of variants of this pod exist.

Initially on fixed-wing gunships such as the Douglas AC-47 Spooky and Fairchild AC-119, the side-firing armament was fitted by combining SUU-11/A aircraft pods, often with their aerodynamic front fairings removed, with a locally fabricated mount. These pods were essentially unmodified, required no external power, and were linked to the aircraft's fire controls. The need for those pods for other missions led to the development and fielding of a purpose-built "Minigun module" for gunship use, designated the MXU-470/A. These units first arrived in January 1967 with features such as an improved 2,000-round drum and electric feeder allowing simplified reloading in flight. The initial units were unreliable and were withdrawn almost immediately. By the end of the year, the difficulties had been worked out and the units were again being fitted to AC-47s, AC-119s, and AC-130s, with a specific ammunition load that replaced every fifth 'ball' round with a tracer round to enable better accuracy by the gunners, and also earning these airborne gunships the nickname 'Puff the Magic Dragon' by the Viet Cong due to their apparent ability of spitting fire and making everything they hit disappear or die. The AC-47 had three side mounted MXU-470/As (four were mounted on its replacement, the AC-119) and when all firing at once created a devastating image in the eyes of the enemy. The first AC-130A Gunship IIs did away with the MXU-470/A mounts and instead used GAU-2/As, and not only had four 7.62mm GAU-2/A minigun mounts, but added four 20mm M61 Vulcan 6-barrel rotary cannons; this configuration was upgraded two years later in 1969 by removing two each of the GAU-2/As and M61s and adding two 40mm (1.58 in) L/60 Bofors cannons in the aptly named AC-130A 'Surprise Package'. This configuration lasted two more years until, in late 1971, the AC-130E Pave Aegis arrived, which did away with the miniguns altogether and one of the 40mm Bofors and instead went to the configuration of two 20mm M61 Vulcan, one 40mm L/60 Bofors and one 105 mm (4.13 in) M102 howitzer, a configuration that lasted until the early 2000s when the AC-130Hs (the AC-130Es had had an avionics upgrade and redesignated to H models) underwent a refit and the two M61 Vulcans were removed and replaced with one General Dynamics 25 mm (0.984 in) GAU-12/U Equalizer 5-barrel rotary cannon (while still retaining the H suffix).

The improved MXU-470/As were even being proposed for lighter aircraft such as the Cessna O-2 Skymaster used by Forward Air Controllers but proved too heavy and cumbersome. A fit of two MXU-470/As was also tested on the Fairchild AU-23A Peacemaker, though the Royal Thai Air Force later elected to use another configuration with the M197 20 mm cannon.

In September 2013, Dillon Aero released the DGP2300 gun pod for the M134D-H. It contains 3,000 rounds, enough ammunition to fire the minigun for a full minute. The system is entirely self-contained, so it can be mounted on any aircraft that can handle the weight, rotational torque, and recoil force (190 lbf) of the gun. The pod has its own battery which can be wired into the aircraft's electrical system to maintain a charge.

Various iterations of the minigun have also been used in a number of armament subsystems for helicopters, with most of these subsystems being created by the United States. The first systems utilized the weapon in a forward firing role for a variety of helicopters, some of the most prominent examples being the M21 armament subsystem for the UH-1 and the M27 for the OH-6. It also formed the primary turret-mounted armament for a number of members of the Bell AH-1 Cobra family. The weapon was also used as a pintle-mounted door gun on a wide variety of transport helicopters, a role it continues to fulfill today.

Users

 * 🇦🇫 afghanistan
 * 🇦🇱 albania - to be mounted on CH-47 Chinook helicopters
 * 🇦🇷 argentina
 * 🇦🇺 australia
 * 🇦🇹 austria
 * 🇧🇷 brazil
 * undefined
 * 🇨🇦 canada
 * 🇨🇱 chile
 * 🇨🇴 colombia Used on UH-60L, Mi-17, and UH-1N helicopters.
 * 🇨🇿 czech republic
 * 🇪🇬 egypt
 * 🇫🇷 france
 * 🇫🇮 finland
 * undefined
 * 🇩🇪 germany
 * 🇮🇩 indonesia
 * 🇮🇶 iraq
 * 🇮🇷 Iran
 * 🇮🇱 israel
 * 🇮🇹 italy
 * 🇯🇵 japan
 * 🇯🇴 jordan
 * 🇲🇾 malaysia
 * 🇲🇽 mexico
 * 🇲🇦 morocco
 * 🇳🇱 netherlands
 * 🇳🇿 new zealand (Testing)
 * 🇳🇴 norway
 * 🇵🇰 pakistan
 * 🇵🇾 paraguay
 * 🇵🇪 peru
 * 🇵🇭 philippines
 * 🇵🇱 poland
 * undefined
 * 🇸🇦 saudi arabia
 * 🇷🇸 serbia
 * 🇸🇱 sierra leone
 * 🇪🇸 spain
 * 🇸🇪 sweden
 * 🇹🇭 thailand
 * 🇹🇷 turkey
 * 🇬🇧 united kingdom
 * 🇺🇸 united states

title: M134 Minigun


text:
Talk:M134 Minigun

Users
The users section needs to be more like that of Walther P5: stating examples of how citizens of that nation used the gun.

Also have any infantry (boots on the ground) people ever held and used a minigun (while sitting, standing, walking, etc.)? It might be too heavy, but if someone has in a military conflict then that could be something to write in the "Users" section. --User123o987name (talk) 08:19, 16 May 2019 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for speedy deletion
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion: You can see the reason for deletion at the file description page linked above. —Community Tech bot (talk) 21:07, 24 May 2020 (UTC)
 * Мініган.jpg

Mini in name
"The "Mini" in the name is in comparison to larger-caliber designs that use a rotary barrel design, such as General Electric's earlier 20 mm M61 Vulcan, and "gun" for the use of rifle ammunition as opposed to autocannon shells. " That's a little bit misleading. It was called the "minigun" because it was directly derived from GE's 20mm Vulcan cannon. The Vulcan was the first and only rotary type cannon in service, so the name isn't to differentiate if from "larger caliber designs", but from the Vulcan alone. It is a "Mini" gun because it's a scaled down Vulcan able to be mounted on lighter aircraft, firing rifle caliber ammunition. It's a "gun" because it's a gun. An autocannon is also a gun. They could have easily renamed the Vulcan the "Megagun" to match and no one could have said they were inaccurate to do so. The name "minigun" was not a serious attempt at making up a descriptor for the new class of weapon, it was mere marketing. The name was catchy and caught on, and so people use it generically for any multiple barrel weapon, even heavy autocannons sometimes, but in reality it's only a "Minigun" because the Vulcan. It was developed before there WERE any other designs to diffentiate from.

Idumea47b (talk) 02:29, 12 September 2020 (UTC)

title: Talk:M134 Minigun


text: Category:Abruzzo

title: Category:Abruzzo


text:
Wikipedia:Articles for deletion/Navigium Flammae

Navigium Flammae was proposed for deletion. This page is an archive of the discussion about the proposed deletion. This page is no longer live. Further comments should be made on the article's talk page rather than here so that this page is preserved as an historic record. The result of the debate was DELETE

 * Seems to be utter nonsense. Delete. —Morven 10:56, Oct 10, 2004 (UTC)
 * Part of a prank already removed from Celt. Delete quickly. _R_ 12:24, 10 Oct 2004 (UTC)
 * Delete. At best a bad joke. And Mr. Picky sez Navigium Flammae = a ship of flame, not ships of fire. Securiger 12:38, 10 Oct 2004 (UTC)
 * Delete. Silliness, although with a thin base in reality (Caligula's expedition to the English Channel). — Bill 15:51, 10 Oct 2004 (UTC)
 * Delete: Prank/hoax, could be speedy deleted. Besides, the top export of Roman Britain was Roman Britons. Geogre 21:09, 10 Oct 2004 (UTC)
 * Delete. Looks like nonsnese. Can't find anything to support the topic. MarkS 22:04, 10 Oct 2004 (UTC)
 * Let's see. No relevant Google hits for "pook", nonexistent on dictionary.com (though "pooka" is a "mischievous spirit in Irish folklore"). Verdict: patent nonsense, belongs to BJAODN. Delete. - Mike Rosoft 12:07, 13 Oct 2004 (UTC)
 * Delete. Although were there a "pook", and it a delicacy, and requiring such treatment, no doubt the Romans would indeed have demanded it! zoney ♣ talk 13:30, 13 Oct 2004 (UTC)
 * Delete. Never heard of this ever, or a 'pook'. -- Mithent 18:43, 15 Oct 2004 (UTC)
 * Delete. It's already on BJAODN. Rickyrab 18:46, 15 Oct 2004 (UTC)

This page is now preserved as an archive of the debate and, like other '/delete' pages is no longer 'live'. Subsequent comments on the issue, the deletion or on the decision-making process should be placed on the relevant 'live' pages. Please do not edit this page.


text: Category:Emilia-Romagna

title: Category:Emilia-Romagna


text:
User:AmeriDesi

I'm a software engineer. I came to the United States in 1980 from Pakistan, where I was born and raised. Married with kids.

title: User:AmeriDesi


text:
Hatzalah

Hatzalah (הַצָּלָה) is the title used by many Jewish volunteer emergency medical service (EMS) organizations serving mostly areas with Jewish communities around the world, giving free medical service to patients regardless of their religion. Most local branches operate independently of each other, but use the common name. The Hebrew spelling of the name is always the same, but there are many variations in transliteration, such as Hatzolah, Hatzoloh, and Hatzola. It is also often called Chevra Hatzalah, which loosely translates as "Company of Rescuers", "Group of Rescuers", or "Rescue Squad". It is the largest volunteer medical group in the United States.

History
The original Hatzalah EMS was founded in Williamsburg, a neighborhood of Brooklyn, New York, by Hershel Weber in the late 1960s. His aim was to improve rapid emergency medical response in the community, and to mitigate cultural concerns of a Yiddish-speaking, Hasidic community. The idea spread to other Orthodox Jewish neighborhoods in the New York City area, and eventually to other regions, countries, and continents. Hatzalah is believed to be the largest volunteer ambulance service in the world. Chevra Hatzalah in New York has more than a thousand volunteer EMTs and paramedics who answer more than 70,000 calls each year with private vehicles and a fleet of more than 90 ambulances.

Hatzalah organizations now function in Argentina, Australia, Austria, Belgium, Brazil, Canada, Israel, Mexico, Panama, Russia, South Africa, Switzerland, United Kingdom, Ukraine, and in 10 U.S. states: California, Connecticut, Florida, Illinois, Maryland, Michigan, New Jersey, New York, Pennsylvania, and Texas. Hatzalah branches are currently being organized in other states as well.

In Israel, there are two Hatzalah organizations operating on the national level: United Hatzalah (איחוד הצלה), and Tzevet Hatzalah (Hebrew: צוות הצלה). While United Hatzalah is inarguably the larger of the two organizations, in the past their volunteers were limited to direct response on-scene care, versus Tzevet Hatzalah volunteers, which are additionally licensed and authorized to provide emergency transport utilizing Magen David Adom ambulances. Currently United Hatzalah - has a wide deployment of active ambulances and several Mobiles Intensive Care Units (always staffed by a specialist doctor and a paramedic) distributed in the greatest cities of Israel, which allows them to transport sick and injured to the nearest suitable medical center, for free.

Operations
Hatzalah uses a fly-car system, where members are assigned ad-hoc to respond to the emergency. The dispatcher requests any units for a particular emergency location. Members who think they will have best response times respond via handheld radios, and the dispatcher confirms the appropriate members. Two members will typically respond directly to the call in their private vehicles. A third member retrieves an ambulance from a base location.

Each directly dispatched Hatzolah volunteer has a full medical technician "jump kit" in their car, with oxygen, trauma, and appropriate pharmaceutical supplies. Paramedic (EMT-P) members carry more extensive equipment and supplies, including EKG, IV, injection, intubation, and other pharmaceuticals. Each volunteer is called a unit (as in, a crew of one) and is assigned a unit number that starts with a neighborhood code, followed by a serial number for that neighborhood (e.g., "Q-120" means "Queens unit number 120" ). Ambulances also have unit numbers in the same format, with the first few numbers for each neighborhood reserved for the ambulance numbers. Some neighborhoods have begun to assign 3-digit unit numbers to their ambulances, using numbers out of the range assigned to human member units (e.g., 900-numbers).

In some areas there may be periods where coverage is not strong enough, for example on a summer weekend. When this happens, coordinators may assign an on-call rotation. The rotation may still respond from their houses, or they may stay at the garage through their shift. In such periods, Hatzalah functions closer to a typical EMS crew setup, though the dispatchers may still seek non-on-call members to respond, and there will still often be a non-ambulance responder as first dispatched, even if that responder starts from the base.

In Israel, United Hatzalah relies upon mobile phone technologies which include an SOS app and a special emergency phone number, 1221, with messages to news organizations distributed by WhatsApp.

Response times
Hatzalah's model provides for speedy first responder response times. Each Hatzalah neighborhood's response time varies. For example, in Borough Park, Brooklyn, daytime response in life-threatening emergency are between 1–2 minutes, and nighttime response times are 5–6 minutes. In the Beverly-La Brea neighborhood of Los Angeles, response times average at sixty-to-ninety seconds. In Israel, the response time is under 3 minutes.

Organization
Hatzalah is not a single organization. Each chapter operates autonomously, or, in some cases, with varying levels of affiliation with neighboring Hatzalah chapters and under a central association.

In New York City's Hatzalah, there is a very simple operational hierarchy. Usually, there are two or three members who are "coordinators", managing all operational aspects of the chapter.

As Orthodox Jews, many volunteers see each other daily during prayers, and especially on Shabbat. This allows them to remain organized, despite the lack of an extensive formal hierarchy.

The coordinators are responsible for recruitment, interaction with municipal agency operations (police, fire, and EMS), first-line discipline, and day-to-day operations. The coordinators often are responsible, directly or via delegation, for arranging maintenance crews, who are often called service members or service units, and for purchasing supplies, ambulances, and other equipment. There is also an administrative function, often separate from the coordinator function. The chief administrator is often called a director or executive director, and this is sometimes a paid position. All other positions in Hatzalah, including coordinators, are held by unpaid volunteers.

Most of the New York State branches have some centralized administration and dispatch functions, known as "Central Hatzalah", or, simply, "Central". The neighborhood organizations under Central are nevertheless independent. Most Hatzalah organizations pattern themselves after the Williamsburg and Central models (see operational descriptions below).

Formally, the New York City-area "Central Hatzalah" is called Chevra Hatzalah of New York. It combines dispatch and some other functions for over a dozen neighborhood organizations, including Williamsburg, Flatbush, Borough Park, Canarsie, Crown Heights, Lower East Side, Upper West Side, Midtown, Washington Heights, Queens, Rockaways & Nassau County, Seagate, Catskills, Staten Island, Riverdale, and others. As each of these areas is otherwise independent, each has its own fund-raising, management, garages, ambulances, and assigned members. Rockland County, NY and Kiryas Joel (Town of Palm Tree) branches have a centralized dispatch system as well, but their central organization is separate from the other New York State centralized functions, and they have a looser relationship with their New York State brethren, though there is a great deal of co-operation among them. Together, the combined New York State branches have grown to become the largest all-volunteer ambulance system in the United States.

Within Israel, the largest local organization is Magen David Adom.

Outside of New York and Israel, there are many smaller Hatzalah organizations. Each of these operates as a self-contained unit as members of a single association, but with no centralized coordination. However, where there are other Hatzalahs nearby, there is often a great deal of co-operation.

In Baltimore, Hatzalah's response area straddles two jurisdictions; Baltimore City Fire Department and Baltimore County Fire Department. Members in Baltimore often work side by side with crews from both services.

Legal status
In the United Kingdom, Hatzalah cannot use blue lights and sirens on their private vehicles. though they are allowed to do so with ambulances.

In England, all Hatzalah chapters are CQC-registered, and they have a memorandum of understanding with local police forces with regards to use of blue lights and sirens, if certain criteria are met. Like any other emergency service, this does not mitigate if a collision occurs, and the service and its members can be prosecuted if deemed to be in the public interest.

In New York, Hatzalah usually use red and blue lights and sirens, like normal unmarked emergency vehicles. In New Jersey, Hatzalah usually use blue lights. Since 2021, Florida law has permitted faith-based volunteer ambulance services to operate, allowing Hatzalah response vehicles to use emergency lights and sirens.

In Toronto, Hatzalah use green lights, having the same legal status as volunteer firefighters who also use green lights in their vehicles.

In Australia, Hatzalah are trained as Community First Responders. They are tasked by the professional services to respond to emergencies, but they cannot use flashing lights or sirens, and they must obey all traffic rules.

Community involvement
Hatzalah organizations are often involved in other community activities, on top of their primary mission of emergency medical work. Many neighborhood chapters sponsor and participate in community events, both within the local Jewish community and in the broader community.

Many Hatzalahs worldwide  run public relations campaigns related to safe drinking on Purim, fire safety on Chanukah, and during Passover preparations. Chevra Hatzolah in New York works closely with the FDNY on this matter.

Specialization of Hatzalah EMS
A number of items that are either unique to Hatzalah, or that are relatively unusual for an EMS, include:

Direct response
Most EMS rely on crews with scheduled shifts operating from a known location. Due to its members and the communities they serve usually living in proximity, Hatzolah relies little on scheduled crews and stations, and, rather, has all service members on call 24/7 and members responding from wherever they are.

Cultural sensitivities
Language, religion, and culture barriers create challenges for an emergency medical service. Hatzalah is built to consider these challenges, especially with regard to Halacha (Jewish law) and communities that only speak Yiddish or Hebrew.

A Jew reluctant to violate Shabbat rules when receiving medical attention may be more at ease and easily convinced of the medical urgency when the EMT or paramedic is a fellow Orthodox Jew. A woman or girl worried about physical modesty and contact may be helped by knowing that a Jewish provider will be aware of the details of her concerns, and will act to reduce the problem as much as possible.

Mental health professionals
Every Hatzalah response crew will include at least one mental health professional (either a psychologist or psychiatrist), even if the emergency is not psychological in nature. The mental health professional functions to deal with potential psychological elements of the medial emergency including: calming the patient before and during transport to hospital, calming surrounding individuals on the scene, and dealing with actual psychological/psychiatric emergencies. Some Hatzalah chapters globally have their own mobile crisis units.

Cost
In areas where the EMS charges a fee, lower income clientele lacking health insurance may have a reluctance to call for an ambulance, unless the evidence of urgency is overwhelming. A volunteer service, with less overhead costs, tends to reduce that reluctance. Hatzolah will often handle "check-out" cases without charge. In this way, the true emergencies among those check-outs may be recognized and treated quickly, where the caller might have otherwise not sought treatment.

Patient advocacy
In contrast with most other EMS agencies, many Hatzalah volunteers will remain at the hospital with the patient long after bringing them to the emergency department. This is especially true during serious cases, where volunteers will remain in order to help the patient and/or their families navigate the sometimes confusing series of events that occur during an emergency. Members will stay to explain, advocate, and sometimes help make arrangements to bring in other specialists or arrange transfer to higher care facilities.

Funding
Across the world, Hatzalah organisations make money by fundraising, either by fundraising dinners, or via public matching funds.

Interaction with other agencies
At times, there have been difficulties in dealing with outside organizations, including other first-responders.

On February 20, 2013, the Federal Communications Commission granted Chevrah Hatzalah's request for a waiver to obtain calling party numbers (CPN), even when callers have caller ID blocking. Calls to 911 are exempt from CPN blocking, but calls to Chevrah Hatzalah do not go through 911. Other Hatzalah dispatch numbers, including other New York State Hatzalah groups, do not have this waiver, but some are working on it.

In general, branches have excellent relations with state and local police and EMS.

An example of those operating in uneven, or otherwise especially challenging situations is Catskills Hatzolah, handling the swelling summer crowd.

Israel's United Hatzalah has shared its expertise with a group of Arab volunteers from East Jerusalem, to form an emergency first response unit called Nuran. The group since has been dismantled, and the volunteers were incorporated in United Hatzalah.

Magen David Adom
United Hatzalah's relationship with Magen David Adom, however, is strained, and MDA has banned its members and volunteers from also volunteering in other rescue organizations, including Hatzalah.

The Chevra NYC Central affiliates boast an excellent relationship with New York City and New York State agencies.

Ezras Nashim
Hatzalah was the subject of controversy as articles in the New York Post and JEMS Magazine criticize the organization for its practice of not allowing women to join. A group of Orthodox women founded an organization called Ezras Nashim, an all-female Orthodox Jewish volunteer EMT ambulance service. They cited the need for modesty and sensitivity to the needs of fellow Orthodox women, with the goal of preserving women's modesty in emergency medical situations, especially childbirth: "This is a woman's job. Historically, women have always delivered babies in traditional Jewish values, pointing to the Hebrew Bible Book of Exodus, where the first midwives were women, Shiphrah and Puah. "In our community, women also have a very strong motivation to seek female doctors", said their lawyer, Rachel Freier, a Brooklyn Civil Court Judge and Haredi Orthodox Jewish mother of six.

Crown Heights riot
Lack of public understanding of Hatzalah operations played a key role in the 1991 Crown Heights riot in Brooklyn. To the general public observing a car crash, it appeared that Hatzalah was there to help the Jewish operator of the car and not the two small children who were severely injured by the car.

September 11 attacks
Hatzalah members were among the first responders at the World Trade Center following the September 11 attacks on September 11, 2001. Alongside other rescue workers, Hatzalah volunteers rescued, treated, and transported victims.

Hatzalah was not dispatched by the city's 911 system, and a print-out of the 911 job from FDNY EMS does not list them as responding units. However, audio recordings exist of Hatzalah's own dispatch, including members calling for help during the collapse of the first tower. There are also well-known photos of destroyed Hatzalah ambulances  and the destroyed cars of Hatzalah members, in the aftermath of the attack.

COVID-19 pandemic
Hatzalah chapters across the United States continued to service Jewish communities during the COVID-19 pandemic. The organization saw a 250% increase in emergency calls during the pandemic. In addition to medical response, Hatzalah worked with rabbis and community leaders to communicate to Jewish communities the need for self-isolation and the implementation of safety precautions. Multiple Hatzalah chapters donated ventilators and masks, as well as other vital personal protective equipment, to local hospitals in need of the equipment.

Surfside building collapse
On June 24, 2021, (10 days after Governor Ron DeSantis signed the law that would allow Hatzalah in Florida to operate) at approximately 1:22 a.m. EDT, Champlain Towers South, a 12-story beachfront condominium in the Miami suburb of Surfside, Florida, United States, partially collapsed, causing the death of 98 people. Four people were rescued from the rubble, but one died of injuries shortly after arriving at the hospital. Eleven others were injured. Approximately thirty-five were rescued the same day from the un-collapsed portion of the building, which was demolished ten days later. Hatzalah of South Florida (HSF) was one of the first agencies on the scene providing triage care to survivors and families. HSF was on site for the duration of the rescue and recovery operation providing medical and rehab support to the IDF search and rescue team from the home front command as well as the out-of-town FEMA USAR teams.

Chapters
Chapters of the organization exist in Argentina, Australia, Austria, Belgium, Canada, Chile, England, Israel, Mexico, Russia, South Africa, Switzerland, and in the United States. The chapters in each neighborhood or city operate independently, though in many cases, affiliations and levels of co-operation do exist between neighboring chapters.

title: Hatzalah


text:
User talk:GreenDayFan

--GreenDayFan 10:59, 10 Oct 2004 (UTC)

title: User talk:GreenDayFan


text:
2004 Japanese Grand Prix

The 2004 Japanese Grand Prix (officially the 2004 Formula 1 Fuji Television Japanese Grand Prix) was a Formula One motor race held on 10 October 2004 at the Suzuka Circuit. It was Race 17 of 18 in the 2004 FIA Formula One World Championship.

Friday drivers
The bottom 6 teams in the 2003 Constructors' Championship were entitled to run a third car in free practice on Friday. These drivers drove on Friday but did not compete in qualifying or the race.

Wirdheim and Briscoe could not got to drive any single lap Friday training sessions. Teams confirmed it as a reason for not driving the drivers that they had a limited number of tyres for very wet weather, and were therefore not sufficient for the cars of the third drivers.

Background
This was Jarno Trulli's first race with the Toyota team after missing the previous race. This was Olivier Panis's last race as he decided to retire from the race seat. But he stayed with the Toyota team, as the test driver.

Qualifying
All the running on Saturday was cancelled due to Typhoon Ma-on, meaning that both the qualifying sessions were run on Sunday morning. Qualifying took place on a track that was still damp but is drying out; Michael Schumacher took advantage of this and, taking to the track among the last thanks to an excellent performance in the first session, won pole position, with a large advantage over his rivals. Second was Ralf Schumacher, while Webber surprisingly took third place, still a full second behind the pole position time. The two BARs of Sato and Button followed, preceding Trulli, Fisichella, Coulthard and Villeneuve. The difficult conditions of the track put several drivers in difficulty: Alonso, Räikkönen, Montoya and Barrichello made mistakes, relegated to the second half of the grid.

Race
After some testing plagued by bad weather, the race started in dry conditions and sunshine. At the start, Michael and Ralf Schumacher had no difficulty maintaining the lead. Webber on the other hand, started poorly and was overtaken by Button, Sato and Trulli. Michael Schumacher immediately gained a clear advantage over his opponents. The only one who drove a similar pace was his brother Ralf, who also went into the pits first on the 9th lap. When Michael Schumacher refueled four laps later, he rejoined the track as the leader, ahead of Button (who started with a two-stop strategy and therefore had not yet pitted). The race for first place was practically over. While the BAR duo fought for third place (Sato with a three-stop strategy against Button's), the race is livened up by the comeback of Barrichello, Montoya, Räikkönen and Alonso; Trulli, however, is relegated and, having started with little petrol on board, has to deal with a Toyota that is very difficult to manage with a full tank of fuel.

On lap 20, Webber retired for a rather unusual reason: the cockpit of his Jaguar inexplicably overheated to such an extent that the Australian driver suffered minor burns on his thigh. After the first series of stops, Trulli, Montoya, Barrichello and Fisichella gave rise to an intense duel, with the Sauber driver having difficulty with the tyres, having to give way to the Brazilian from Ferrari, but managing to defend himself from the other two until his second refueling, on the 24th lap. Michael Schumacher continued to lead undisturbed and didn't relinquish the lead for one lap. His brother Ralf also had no particular difficulties defending his second place from the two BAR drivers. Coulthard climbs sharply up the overall standings and initially only makes two stops. With around twenty laps to go, the Scot was in fifth place, having refueled for the second time.

Behind him, however, Barrichello quickly recovered. On lap 38, the Brazilian attempted an attack, but the McLaren driver came out of the corner and the two subsequently touched each other. The two cars were damaged beyond repair and both had to give up. Alonso moved up to fifth place. Meanwhile, Button prevailed against his teammate in the duel for the podium. Sato got off to a slow start and pain from an old shoulder injury returned during the race and had to go without liquid for much of the race when a water bottle stopped working. BAR virtually secured second place in the Constructors' Championship. The team increased its advantage over Renault to 16 points with one race remaining.

There were no more surprises in the final laps and Michael Schumacher won ahead of Ralf Schumacher, Button, Sato, Alonso, Räikkönen, Montoya and Fisichella. It was Ferrari's fifteenth victory of the season. In doing so, they equaled the previous record of the McLaren, which won fifteen out of sixteen Grands Prix victories in, and the Ferrari, which won fifteen out of seventeen in.

It was the last time the Schumacher brothers finished in 1–2 formation (having done so on four other occasions: 2001 Canadian Grand Prix, 2001 French Grand Prix, 2002 Brazilian Grand Prix, 2003 Canadian Grand Prix). It was also the last 1-2 finish between German drivers until the 2013 Indian Grand Prix.

Qualifying
Qualifying was held on Sunday morning due to weather conditions on Saturday.
 * Notes
 * – Zsolt Baumgartner received a 10-place grid penalty for an engine change.

Race

 * Notes
 * – Zsolt Baumgartner started the race from the pitlane.

Championship standings after the race

 * Bold text and an asterisk indicates the World Champions.

 * Drivers' Championship standings

 * Constructors' Championship standings

 * Note: Only the top five positions are included for both sets of standings.

title: 2004 Japanese Grand Prix