Talk:Jet engine/Archive 3

Rocket turbine engine
I've added a reference to Rocket turbine engine in the See also section. The Rocket turbine engine page is an orphan article that I am trying to fix by finding other articles that will link to it (as part of the Wikipedia Backlog Drive). Unfortunately, the Rocket turbine engine is also a stub, so it doesn't say very much. TheAMmollusc (talk) 08:29, 3 March 2011 (UTC)


 * It's worse (than that Jim) - its a two sentence unreferenced stub. As it stands I don't think it would survive AfD. Why not remove the link form the see also of this article and put it back in when there's actually something resembling an article at the other end? GraemeLeggett (talk) 11:28, 3 March 2011 (UTC)


 * Delete it, delete the links. Andy Dingley (talk) 11:32, 3 March 2011 (UTC)

Meanwhile, I'm still de-orphaning articles, and have found another one for you experts. You might like to have a look at Jet engine compressors, and see if you can link to it from anywhere (perhaps also giving the target article an upgrade)... or, if you consider it more appropriate, sign its death warrant. (I'm sorry I have to pass this over to you; I have to bow to your greater knowledge on this). TheAMmollusc (talk) 13:26, 28 April 2011 (UTC)

Efficiency
So about how much exactly is jet engine efficinecy? I mean a formula is fine and dandy but doesn't tell anybody what a realistic range of operating efficiencies can be expected from a jet engine. Are they 25% effiecient, 33% efficient, 50% efficient? Can you give at least some idea what kind of efficiencies can be expected from a jet engine? That much seems like a basic element of the description of the jet engine but is t0otally lacking in this article 99.2.69.235 (talk) 04:29, 1 May 2011 (UTC).

Turbofan
I think this statement in the section: 'The bypassed flow is at lower velocities, but a higher mass, making thrust produced by the fan more efficient than thrust produced by the core.', is ambiguous. Paquitotrek (talk) 15:57, 17 August 2011 (UTC)

image for turboprop
I'm an engineering student, not an expert on jet engines, but I think the image for the turboprop is inaccurate. the image seems to show exhaust gases being directed downwards, implying that the engine doesn't use them for thrust. but the body of the article states that turboprop design takes both the propeller and the exhaust gases into account as a source of thrust. the image should depict the gases being ejected straight back rather than downwards- in fact, a google images search makes this seem to be the only available image of a turboprop that depicts gases being directed downwards. as far as I know, exhaust gases are only directed downwards in turboshafts, in which their contribution to propulsion is basically ignored, or in engines designed for V/STOL. — Preceding unsigned comment added by 94.159.151.159 (talk) 06:51, 25 December 2011 (UTC)

Removal of a cited statement
User:Incompetence wants to remove HERE a cited statement and its citation with the edit summary allegation that "it's not a competition to see how many times you can use the word 'jet' in different ways in one sentence" & has been invited to discuss his concerns on this page. My name is Mercy11 (talk) 16:29, 17 January 2012 (UTC), and I approve this message.


 * I removed it because it was so bad I'm still wondering if it's deliberately so. The fact that you're revert warring it only increases my concerns. It's been reverted by two different people so far, more than once each. At the very least it's the clumsiest sentence I've ever read.- Sheer Incompetence (talk) Now with added dubiosity! 17:33, 17 January 2012 (UTC)


 * The 5 accussations above require facts to be credible. The statements above are just accussations and all lack supporting facts. I just don't like it is not a reason to revert. Mere previous reverts by -any- number of other editors doesn't prove anything.


 * The information added fulfills all requirements of WP:Criteria for inclusion and WP:BURDEN. If there is a valid reason to remove the material, it is not mentioned in the statements above from User:Incompetence.


 * My name is Mercy11 (talk) 18:49, 17 January 2012 (UTC), and I approve this message.


 * Cut the bullcrap. According to what you've written jet engines are only used on jet aircraft. As you've defined it, if you unmount a jet engine from an aircraft, it's no longer a jet engine. World land speed record cars aren't jet aircraft and so aren't driven by jet engines??? Wrong. It's easy to reference that they are jet engines on board those cars.- Sheer Incompetence (talk) Now with added dubiosity! 19:37, 17 January 2012 (UTC)
 * Jet engines are defined by how they work, not what they're used for, but your lousy reference (which I couldn't even validate) apparently defines it by what it's used for, and the reference doesn't seem to be adequate for the kind of usage you're making of it.- Sheer Incompetence (talk) Now with added dubiosity! 19:37, 17 January 2012 (UTC)
 * The use of the slang word 'jet' to mean jet aircraft is also particularly bad. I can only imagine you're doing that deliberately, since you've specifically linked to the jet aircraft article.- Sheer Incompetence (talk) Now with added dubiosity! 19:44, 17 January 2012 (UTC)

Coanda
Was it not agreed (with references) that Coanda was a ducted fan and not a jet engine as described in this article. We appear to add and remove it regularly so do we need a section explaining why the 1910 Coanda is not a jet? MilborneOne (talk) 22:15, 19 September 2010 (UTC)
 * The Coanda 1910 engine was definately a ducted centrifugal fan driven by a piston engine and not a jet engine- but discussing that in the article is probably invoking WP:BEANS as it is giving something that the proponents of the fantasy that it was a jet engine can latch on to. If necessary they should be discused in Coanda's article, not here, as it has absolutely no relavence whatsoever to this article.Nigel Ish (talk) 23:00, 19 September 2010 (UTC)
 * I think that removal of the disputed bits is the best answer. We can insert a hidden statement saying do not add this stuff... take it to Coanda-1910.
 * If the kerfuffle over which version is true is limited to Wikipedia talk page discussions, then it is not notable. However, if this discussion breaks over into world news then it will have earned a place in this article. Such a case is likely to happen soon as the Romanians are planning a centennial celebration of their being first in jet technology, the celebration stretching from October to December this year. If a magazine or news article comes out describing how the Romanian version of Coanda's 1910 aircraft is going against several giants of aviation history research, then we have a new situation, requiring an explanation. Binksternet (talk) 00:09, 20 September 2010 (UTC)
 * Let's see if the the powerplant of Coanda 1910 was a ducted fan.
 * I'm just a normal licensed pilot and from my little experience I have never heard on any propelled airplane with an 50 HP engine and weight of half a ton ( 420Kg + pilot) taking-off by itself( this can be analyzed from the original pictures. I hope there is no question about the pictures ) And especially a ducted fan. So basically if the powerplant was a ducted fan than there was absolutely no chance to take-off. But it can be noticed from the pictures that the plane was quite advanced at the time when the pioneers were still jumping from rocks with textiles. As everything was invented in that plane from scratch, probably its construction was very expensive, as Coanda stated in many interview and can be seen from his career path after 1910. So the very expensive plane was just making ground runs in some field in France. Because Henri Coanda in his 20's is planning to make an announcement 40 years later in '50s or '60, he is burning down his own very expensive airplane just to hide the traces for the next 40 years. Very smart move. And another very amazing fact. After the "accident" he is starting a very elaborous work on something which will be named after his name: Coanda effect.
 * So basically when doing this ground rounds with his ducted fan "airplane" he managed somehow to see the airstream (there is no flames in the ducted fan as only the turbine rotated by the piston engine is pushing the air from front to back). So basically he was able to see the wind. What a gifted 24 years old.
 * Putting back to back what is written above, as a normal person, I really cannot understand what are the basis for this ducted fan theory. Lsorin (talk) 12:27, 20 September 2010 (UTC)


 * It looks like I started to get personal threats. Is this the way Wikipedia works?
 * Please check this links:
 * Romanian Air Force
 * 100 years
 * Discovery Civilizations Channel


 * Lsorin (talk) 07:03, 20 September 2010 (UTC)


 * That is not a personal threat, it is a friendly warning against making four reversions in 24 hours. Unfortunately, you went on to make that fourth reversion, even after the friendly warning. Binksternet (talk) 16:05, 20 September 2010 (UTC)


 * There is no doubt that young Coanda was an intelligent man, and there is no doubt that his 1910 engine was ingenious. What Gunston, Gibbs-Smith and Winter say about it is in agreement with your assessment that a 50 hp Clerget is not powerful enough to help the aircraft take off—they say that it had no combustion in the airstream, and Gunston says that he does not believe the stated thrust figure of 220 kg (485 lb). Both Gibbs-Smith and Winter agree with you that there was absolutely no chance for it to take off; they say that the aircraft never flew. Gibbs-Smith denies that the aircraft was tested at all at Issy, not ground runs, not an accidental flight. Binksternet (talk) 16:14, 20 September 2010 (UTC)


 * Whittle's first engine, the WU, required 3,000 shp from the turbine just to drive the compressor, and produced around 850lb of thrust. The later Rolls-Royce Derwent required around 6,000 shp to produce around 2,000lb. Producing a claimed 485lb of thrust from a mere 50 hp seems wildly optimistic, especially considering the state of fan design at the time. The fan was presumably geared up to the 4,000rpm quoted.


 * Some Flight references to the "Coanda Turbo-Propulseur" in various issues here: and


 * BTW, Coanda's term "Turbo-Propulseur" itself is misleading as the device contains no turbine, although that may just be due to a difference in language between French and English. Charles Gibbs-Smith's comment is correct, in that the 'engine' exhausted back around the fuselage, and so as he says, if any sort of fuel was injected into the airstream and burnt the pilot would have been roasted. The installation was similar to that of a radial engine with a NACA cowling, with the thrust produced being exhausted around the 'cowling' circumference in the same manner as conventional radial's cooling air. Coanda himself later became Technical Director of the Bristol Aeroplane Company so he wasn't without talent. I suspect that the claims made for him in recent years are not ones that he would have made himself as the internal combustion gas turbine of today is quite different from his concept, as it is from Campini's.  — Preceding unsigned comment added by 80.7.147.13 (talk) 10:23, 18 July 2012 (UTC)

Inactive references in the "Engine thrust to weight table"
References numbered 40 and 47 in the "Engine thrust to weight table" are no longer active and need to be deleted or replaced with active references.

That table was created by a template, which I cannot find. It was and is a bad idea to have a table in an article created by a template. That makes editing the table very difficult and needlessly time consuming. mbeychok (talk) 16:23, 7 March 2013 (UTC)


 * I have now found the table template and removed the two broken/inactive reference links (which were also incorrectly formatted).mbeychok (talk) 17:23, 7 March 2013 (UTC)

According to the definition in dictionary, Coanda 1910 was a jet plane
Even if Coanda 1910 had used just a ducted fan powered by a piston motor, the overall engine fits the definition of a jet engine. Coanda 1910 used oxigen to burn fuel and produced a backward discharge of gases that pushed the plane forward. This is in the definition of a jet engine.

Coanda 1910 was not a turbojet aircraft but definitely was a jet plane.

"Definition of JET ENGINE

An engine that produces motion as a result of the rearward discharge of a jet of fluid; specifically : an airplane engine that uses atmospheric oxygen to burn fuel and produces a rearward discharge of heated air and exhaust gases" source: http://www.merriam-webster.com/dictionary/jet%20engine

"jet engine

1. An engine that develops thrust by ejecting a jet, especially a jet of gaseous combustion products.

2. An engine that obtains the oxygen needed from the atmosphere, used especially to propel aircraft and distinguished from rocket engines having self-contained fuel-oxidizer systems." Source: http://www.thefreedictionary.com/jet+engine


 * All of this has been hashed out at the Coandă-1910 talk page, in gigantic rambling discussions. The upshot of all the discussion is that the Coandă-1910 as shown to the Paris public is not known to have exhaust routed to help thrust. The aircraft never flew. Binksternet (talk) 16:38, 23 March 2013 (UTC)
 * The Clerget engine exhaust would not have helped thrust too much because a piston engine is designed to extract as much energy as possible from the hot gases inside its cylinders. HOW MUCH THRUST DO YOU GET FROM THE EXHAUST GASES OF YOU CAR?  — Preceding unsigned comment added by 70.83.160.23 (talk) 21:54, 23 March 2013 (UTC)

Coanda 1910 was a jet engine working in "cold thrust" regime, at least
Cold Thrust - Hot Thrust; Both regimes = jet propulsion

According to this page http://modelingmadness.com/scott/axis/ity/campinipreview.htm Campini Caproni jet plane could fly at 200 km/h using just the compressor, without injecting fuel and igniting the mixture.

"On the cold thrust alone, the Campini Caproni was capable of speeds over 200 kph, however with the addition of the 'afterburner', speeds easily doubled to 400kph."

In case Coanda had not injected fuel his Coanda 1910 power plant would still have been a jet engine working only in the "cold thrust" regime.


 * The Coandă-1910 as shown to the Paris public was little more than a ducted fan powered by piston engine. The aircraft never flew. Binksternet (talk) 16:38, 23 March 2013 (UTC)

Binksternet you seem to be one and the same individual with "romanianlies". You are known for your lack of arguments, lack of technical background, mistrust, lies, hate, etc.. It looks like there is something wrong with you. You do not behave like a normal individual. It does not matter Coanda 1910 flew or not as long as "aeolipile", for instance, appears in the page of "jet engine" despite the fact it never flew!

Coanda 1910 power plant has its place in the history of jet engines intended for planes.

Adding the exhaust gases from the Clerget 4 cylinder engine and/or injecting fuel in the air blown back by the compressor would not have added too much thrust because the exhaust gases are relatively cool when they exit a gasoline piston engine, otherwise the motor is not efficient, also if the compressor does not increase the pressure behind it, to a few times the atmospheric pressure, burning fuel in the jet of air blown by the compressor would not add too much thrust.

Coanda 1910, just as a ducted fan powered jet plane, was efficient because it burned the gasoline in the Clerget engine at high compression levels.

What you do not understand Binksternet is that it does not matter where you burn the gasoline in a jet engine seen as a black box. What matters is to burn the fuel as effectively as possible and to obtain the maximum thrust for a given amount of fuel.

Model jet planes flown by hobbyists use ducted fans powered by piston engines. — Preceding unsigned comment added by 70.83.160.23 (talk) 21:29, 23 March 2013 (UTC)

History
Quote "By the 1960s all large civilian aircraft were also jet powered, leaving the piston engine in low-cost niche roles such as cargo flights." I question this claim. Ignoring the vague term "large civilian aircraft", I do not think that ALL large passenger and cargo planes were jet powered by 1960. So either provide a solid reference for this, substitute "most" or "almost all" for "all", or change "by the 1960s" to "by the end of the 1960's". I flew in the 60's I am pretty sure I flew on quite a few prop jobs, not prop jets, I think. How about in South America and Africa and Asia (& eastern Europe)? All were "jet powered"?? I doubt it... It needs verification, at least.72.172.10.35 (talk) 15:26, 3 September 2013 (UTC)

Coanda a motorjet?
Coanda's own patents(British patent #GB19112740(A), Swiss patent #CH58232(A), and his original French patent as well)describe the 'turbopropulseur' engine of the 1910 Coanda as a ducted fan. There is no mention whatsoever of fuel injection or combustion in these very detailed descriptions. The detailed diagrams agree completely with the descriptions. The various magazines and journals which covered that airshow (Cassier's Magazine (1911) volume 39 page 199; Popular Mechanics March (1911) page 350; Technical World Magazine (1911) Volume 15 page 615; Aircraft (1910) Volume 1 page 367) also describe the 1910 Coanda as a ducted fan. Coanda only started claiming that it was a motorjet after others invented the jet engine. Other than his own personal claims made after WWII, which varied widely between tellings, there is no evidence that it was anything but an unsucessful attempt at a ducted fan. Is a complete lack of proof, and a huge mountain of evidence to the contrary, sufficient reason to stop saying that he invented the jet engine? —Preceding unsigned comment added by Romaniantruths (talk • contribs) 23:25, 2 August 2010 (UTC)


 * Before Whittle's patent all other (usually theoretical) designs either used a turbine to drive a propeller, making them turboprops, such as those envisaged by A. A. Griffith at the RAE Farnborough in the 1920s, or used no turbine at all, as in the case of Coanda and the Caproni Campini's Motorjet, by-passing any need for a high-temperature/highly-stressed turbine section which needed suitable materials which, with the possible exception of stainless steel, were generally unavailable at the time. Whittle's concept used the exhaust gas from a high-temperature turbine (which was only there to power the compressor) as jet thrust and his was the first to do so, and in his case it was only the availability of newly-developed high-temperature/high-strength alloys from the likes of High Duty Alloys, Nimonic, and similar, that made the use of a turbine and the high temperatures and pressures needed to get an engine to run as a self-sustaining unit, possible. So, it would not have been possible to build a running jet engine any earlier despite what other people might like to believe, as the high-temperature/high-strength alloys needed for components such as the highly stressed turbine, and the combustion chambers, were not available until the late 1930s - you need to run an engine at a high enough temperature and pressure to get sufficient thermal efficiency to enable it to run continuously - suck-squeeze-burn-blow-suck-squeeze..,etc., if you'll forgive the (unintentional) double entendre. If all you want to do is drive a fan from an external source such as a piston engine then, as there are no extremely hot and highly-stressed areas of the 'engine', that would have been relatively simple, as the Caproni Campini proved, but you won't get much power for all the effort involved. Without a 'hot section' containing a turbine the 'engine' isn't worth the effort for all practical purposes. Which is why when you get on a jet airliner to go on your holidays the odds are that it will be powered by engines devised by Whittle, and not Coanda or Campini. —Preceding unsigned comment added by 86.112.68.212 (talk) 22:55, 10 August 2010 (UTC)

You seem to have completely missed my point,and wasted a good deal of space with an irrelevant basic description of how a jet works. The Coanda 1910 had no fuel injection or combustion. It was just a ducted fan according to all contemporary references. Are you trying to argue that a ducted fan is a jet because it emits a jet of air? So does a propeller. And if anyone wants to argue that most of the propulsion of a propeller comes from the reduction of pressure on the front of the blades, this is also described by contemporary sources as a primary component in the hoped-for thrust from Coanda's turbopropulseur. This is why it was often referred to as a 'suction turbine' in the periodicals of the day. Many contemporary accounts of this non-jet are available for free reading at Googlebooks. Use the date function on the advanced search for the opinions of people who actually saw the plane at the 1910 Airshow. The pertinent articles were mostly published in 1910-1912. Romaniantruths (talk) 20:58, 25 August 2010 (UTC)
 * Coanda-1910 is considered by most scholars and aviation historians as the world's first jet (see the talk page from "Coanda-1910" and bibliography there). Only contesters are Gibbs (with no technical qualifications and who contradict himself in his supositions about the engine and how it worked) and Winter, a former military journalist with a degree in history. Peoples like Harry Stine (rocket scientist and aeronautics and science prolific author who worked with Coanda and had acces to all his documents and patents), or W. Boyne, former director of Air and Space Museum, colonel in Air Force and as well a prolific author and aviation historian clearly stated that Coanda-1910 was a "primitive jet" who flew in 1910. Obviously they are way much more competent then Gibbs or Winter, and their opinion are held by most of others who dealt with the subject —Preceding unsigned comment added by 79.116.209.75 (talk) 09:39, 28 September 2010 (UTC)


 * No, Coanda-1910 is not considered world's first jet by most scholars and aviation historians. This is made quite clear on the talk page for Coanda 1910. All contemporary coverage of this plane clearly describes it as a ducted fan. Coanda's own patents show it to be a ducted fan. The brochure Coanda handed out about his plane at the 1910 Paris airshow show it to be a ducted fan. No one ever claimed anything else until the 1950's when Coanda started making these palpabably false claims. They were supported by the Romanian government in much the same way that the USSR began claiming to have invented basically everything in the 1950's. All later references to a 'Coanda jet' trace back to these claims made 40 years after the fact which are in blatant contradiction of the earlier references, patents, and Coanda's own earlier descriptions. The above anonymous IP has been trying to obfuscate these facts for months.Romaniantruths (talk) 22:08, 21 October 2010 (UTC)

The piston driven component did not just force air through a duct. It powered a compressor, aft of which fuel and air were mixed and burned in a combustion chamber. The reactive force, i.e. the jet exhaust, thus created, was far more than could be delivered by the piston engine itself. So this whole "ducted fan" theory is ridiculous and biased as it always is when it comes to show that the english and americans did not actually invent everything but merely developed already existing ideas. — Preceding unsigned comment added by 82.76.188.137 (talk) 07:57, 29 August 2012 (UTC)


 * A search for Charles Gibbs-Smith aviation history articles in Flight here;


 * ... and a photo of the 1910 Coanda biplane with 'ducted-fan' here: - Page 1 of 1953 article here:  - detailed letter explaining Coanda's concept here:  — Preceding unsigned comment added by 80.7.147.13 (talk) 13:33, 9 October 2013 (UTC)
 * Thanks for the links, they're worth adding, if not already in the Coanda-1910 article. The extra detail on the heat exchangers is very welcome (does this explain why the duct appears to be made of copper, not aluminium?). I quote, "He only jut missed inventing the aircraft gas-turbine by not thinking to inject a fuel" Andy Dingley (talk) 14:11, 9 October 2013 (UTC)


 * I don't know about the copper/aluminium piping bit, although copper piping would probably have been easier to obtain and fabricate into a combined radiator/heat exchanger, as copper piping was by then used in domestic heating and in car radiators, whereas I would assume that aluminium piping was probably a rare and expensive item until much later. Copper was widely used in car and other automotive radiators as the piping was easier to bend.


 * From reading the letter it would appear that the Coanda device was a variation on the use of the Meredith effect to augment the thrust of the propeller/fan, but incorporating the additional thrust effect later obtained with ejector exhausts. So it basically used waste heat from the radiator to augment the thrust, albeit inefficiently due to the state of development of engines/installations at the time. TBH there probably isn't enough power to be obtained from this sort of system to make it worthwhile even today. I suspect that he would probably have had more luck with that particular aeroplane if he'd just used a conventional propeller. — Preceding unsigned comment added by 80.7.147.13 (talk) 16:21, 9 October 2013 (UTC)
 * There was actually more benefit to it at that time. Owing to the low compression ratios of the period and so the inability of the piston to extract much work from the combustion gases, exhaust temperatures were higher then than today and there was much more energy wasted in the exhaust. It's one reason why there was interest in the Atkinson cycle, six-stroke engines etc. and why this went away in the 1920s when better combustion chamber design and better fuel chemistry allowed higher compression ratios. Just look at the trouble with exhaust valve burning for engines of this vintage. Andy Dingley (talk) 16:38, 9 October 2013 (UTC)


 * You may well be right, but unfortunately for Coanda there were far better solutions already available at the time, i.e., simply fitting a better propeller. Normal airscrews were already of sufficient efficiency to allow powered flight, as had been proven in the preceding few years since the Wright Brothers, so although Coanda's idea may have had some merit, if he was attempting to fly an aeroplane it was perhaps a bit premature. For one thing, at a time when even a little too much weight was enough to prevent flight, the addition of all that 'plumbing' and a fan/propeller of dubious efficiency may have been enough to have ensured that the aeroplane never made anything other than a short hop - that's if it was even able to move under its own power.


 * Reading the linked article on the 1910 Biplane and the numerous claims that Coanda himself and others have made it seems only fair to point out how absurd such claims are, and that anyone attempting to put forward such claims seems ignorant of some basic facts, e.g., if the exhaust stream did include some combustion of fuel then how did Coanda prevent the hot exhaust gases setting the wooden fuselage directly behind the hot stream of gases on fire. How did Coanda prevent severe burns to the pilot, due to his proximity to the extremely hot 'jet' stream behind the 'engine'. In the picture of the aeroplane why is there no staining or discolouration of the area behind the annular cowling where the exhaust exits, assuming that it ever ran its engine. UPDATE; After further reading it appears that the fuselage was 'protected by asbestos in vulnerable places' so all is well provided the pilot doesn't need to sideslip. One presumes that the unfortunate aviator is already provided with matching asbestos suit, and also oxygen equipment, because it must have been pretty hot in there, and the carbon monoxide fumes must have been pretty lethal. As late as 1940 Hawker's lost a number of Typhoon pilots due to CO seeping into the cockpit, leading to temporary regulations about going on oxygen before starting the engine until a fix was found, so Coanda's job piloting the biplane back in 1910 must have been pretty horrendous.


 * ... and the other perhaps better question to ask is, if the device was so good back in 1910, then why isn't everyone in the aeronautical world now using it. What a waste of man hours, and research wasted in the search for better engines and airscrews in the intervening years, all the time and effort wasted in developing the internal combustion gas turbine, when all they needed to do was to go back to a 1910 aeroplane. Seriously, if Coanda's device had been of any use then one side or the other would have developed it in the period 1914-1918 or 1939-45, and they didn't.


 * Coanda is rightly known for the fluid dynamics effect he described, but as for his 'engine' it was, unfortunately, like Campini's motorjet, an aeronautical dead end. That's why you don't see them today. — Preceding unsigned comment added by 80.7.147.13 (talk) 17:48, 9 October 2013 (UTC)


 * I'm guessing that you're not familiar with the vast edit-warring at WP (read the likely talk pages) as to claims that Coanda did exactly this. Andy Dingley (talk) 18:19, 9 October 2013 (UTC)


 * LOL! - yes I am, thank you Andy - but that doesn't make the claims true. I am merely pointing out how unlikely they are. Readers can then make up their own minds. Personally, I don't care one way or the other. But thanks for your informative and always interesting comments.


 * However it would be nice to see a full-size working reproduction of the 1910 Biplane - if only because I would be curious personally to see after a few engine test runs with the combustion system described, and with the test pilot sitting in the aircraft, how close-by the erstwhile pilot eventually wants the precautionary ambulance positioned. That's if he still wants to get back in the aircraft at all after the first engine run. I suspect the effect would be rather similar to sticking one's head and as much of one's torso as one can manage up the jetpipe of an idling Armstrong Siddeley Viper.
 * There's one in Romania that they built for the centenary. There's some stuff published about it, but not AFAIK in translation. Andy Dingley (talk) 22:15, 9 October 2013 (UTC)

Thanks, I saw the image in the linked article - BTW, "Augmented Flow" a 1946 Flight article on Coanda's use of what is now known as boundary layer control. — Preceding unsigned comment added by 80.7.147.13 (talk) 23:33, 9 October 2013 (UTC)

It's very hard to asses the claims that appear to have been made about the 1910 Biplane without seeming to be unkind to Coanda, but in his defence it needs to be pointed out that the claims were made when Romania had a communist regime under the likes of Nicolae Ceaușescu, et al, who were not noted for their liberal views, and so Coanda may have been put under considerable pressure to make these claims for propaganda purposes. The 1910 Biplane was reasonably well known in aeronautical publications back in the 1970s - the Kenneth Munson/Blandford series of books for a start - but IIRC it was only claimed to be an early attempt at a what later became known as a ducted fan. IIRC, there was never any attempt at a claim that the engine involved combustion of fuel in the duct, i.e., that it was a primitive motorjet engine. This claim is not really credible for the reasons I stated above. It would have helped this claim if there had been some sort of documentary evidence, photographs, etc., but without them the claim appears very doubtful. — Preceding unsigned comment added by 80.7.147.13 (talk) 09:36, 13 October 2013 (UTC)

As an illustration of the sort of temperatures involved, the heat put out of the jetpipe by the Goblin engine of the de Havilland Vampire when idling - i.e., with the throttle fully closed and the aircraft stationary - was enough to soften the tarmac upon which the aircraft was standing. At idle the engine was only producing 150 lb of thrust.

At the Vampire development stage with the lowered tailplane position, before the definitive engine fuel supply/demand system had been worked out, on engine start 'lighting up' was spectacular if ignition wasn't achieved immediately on injection of fuel because when combustion was eventually obtained inside the combustion chambers the excess fuel inside them would ignite suddenly leading to 'torching' out of the jetpipe, and this was so hot that they had to drape asbestos matting over the Vampire's tailplane when engine starting, as otherwise it got scorched.

... in other words, you really don't want any sort of 'jet engine' exhausting into your face. — Preceding unsigned comment added by 80.7.147.13 (talk) 08:56, 15 October 2013 (UTC)

Energy efficiency
"Cycle efficiency is highest in rocket engines (~60+%), as they can achieve extremely high combustion temperatures and can have very large, energy efficient nozzles. Cycle efficiency in turbojet and similar is nearer to 30%, the practical combustion temperatures and nozzle efficiencies are much lower"

I think the nozzle efficiency statements are misleading in suggesting turbojet much lower. For SSME nozzle efficiency = .977 ref Engineering at Boeing - Threshold Journal: Nozzle design. Turbofan nozzle efficiency = .968 ref Jet Propulsion Cumpsty p109.

Also "The exact formula for air-breathing engines moving at speed with an exhaust velocity is given in the literature as:[27]"only applies if fuel flow is neglected so take out "exact" or add fuel flow note ref Cumpsty p24Pieter1963 (talk) 01:15, 4 April 2014 (UTC)

Image: 20140308-Jet engine airflow during take-off.jpg
The caption for this image contains the text "Jet engine airflow during take-off. (Click on picture for bigger view.)" is the "(Click on picture for bigger view.)" required for this picture, or is it standard Wikipedia policy to have a enlarged image (if available) shown when clicked on. I propose the removal of the text "(Click on picture for bigger view.)"

Tanishq.dubey (talk) 16:37, 10 July 2014 (UTC)


 * CLICKHERE seems to have the appropriate guidance, which also fits in with your thinking. GraemeLeggett (talk) 20:37, 10 July 2014 (UTC)

It seems like the text has not been removed, can a auto-confirmed user do this? I am not yet autoconfirmed. Thanks

--Tanishq.dubey (talk) 16:26, 12 September 2014 (UTC)

A Better Summary Needed
This page badly needs a simplified 'For Idiots' section or a separate 'Basic Guide' page. For those of you who have contributed to the page, I know that it seems really really important to choke the page full of absolutely perfectly correct information about all these various kinds of engine, but this page is extremely unhelpful for someone who is trying to learn what a jet engine (the kind attached to an air liner) is and how it works. For all of you guys going into serious depth about all kinds of interesting things, no-one has sat down and tried to read the page as someone with no knowledge of the subject and it really shows. No where on the page can you find a simple explanation of how a jet engine works.

The simplest way I can put it is this - The top line of the page says that jet engines, rocket engines and ramjets are all pretty much the same thing. And I'm sure that's true. But if a kid reading something for science class comes here trying to understand the subject it's really confusing to have all of that thrown at you at the same time. Most people get how a firework works, and just by looking they can see that a jet engine on an airplane is something extremely different from that. The similarity they share (which I think is that they use hot propellant gas to make them go?) I'm sure makes them part of the same category of engines, but clearly the way they generate that is extremely different but if you're a kid the page tells you right away that they are the same. It also lists off three other types of engines you don't understand and says they are the same too.

The problem is this - If you know what exact kind of jet engine you want to know about, this page will tell you specifically how that kind works. But if you know nothing about jet propulsion there is no overview here to help you. There are no basics here at all. None. The page is wordy as hell and uses huge amounts of jargon without making any effort to really explain what it's talking about. Can someone who knows this stuff well please write a nice clear hundred words explaining the basics without jargon? 86.152.60.51 (talk) 21:56, 30 December 2014 (UTC)

Motorjets are not "non-continuous combustion" types.
At the bottom, motorjets are listed alongside pulsejets as "non-continuous combustion" jet engines. I may be totally wrong, but I thought that pulsejets were non-continuous because the combustion takes place in pulses or "flashes", rather than a continuous burning with a steady flow of compressed air. But to my knowledge, a motorjet works exactly like a typical turbojet, except it uses a secondary piston engine to drive the compressor, rather than a turbine stage. That should mean a nice, continuous flow of air and a steady flame inside of the jet portion of the engine, just like your typical turbojet (provided the engine is working correctly). Granted, I suppose the piston engine component could be considered "non-continuous", as its fuel is burned in flashes after TDC, but I don't think that was the point of the term "non-continuous combustion". Just a thought..45Colt 05:30, 11 August 2015 (UTC)

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Semi-protected edit request on 21 November 2015
The Saturn V had five F-1 engines, so "F-1 (Saturn V first stage)" is misleading. Please change to "F-1 (5 F-1's used in Saturn V)" or (not as good) "F-1 (used in Saturn V)". "Stages to Saturn", Roger E. Bilstein, 1996.

71.106.213.212 (talk) 04:37, 21 November 2015 (UTC)
 * It is usual to only describe the performance characteristics of a single engine, even when several are used on the machine — see for example the NK-33 or Rocketdyne F-1 articles. In the table you are referring to, this is the convention used (Concorde had four Olympus, etc). Unless other editors see it as misleading, I think it should be kept that way. Ariadacapo (talk) 06:33, 21 November 2015 (UTC)

Semi-protected edit request on 21 November 2015
71.106.213.212 (talk) 04:23, 21 November 2015 (UTC)
 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. clpo13(talk) 20:45, 21 November 2015 (UTC)

Thanks
I've just read the lede and history sections and want to thank the authors for the clear, accessible language. A joy to read. --Anthonyhcole (talk · contribs · email) 05:36, 3 April 2016 (UTC)

Semi-protected edit request on 11 May 2016
Why, at the history section about jet-engines the Coanda airplane from 1910-1912 (which used indeed a compression-turbine) is not even MENTIONED???. Henri Coanda is not an unnknown name and his achievements are WELL-ESTABLISHT. It si OUTRAGEOUS! The correct details on wikipedia are here> https://en.wikipedia.org/wiki/Henri_Coand%C4%83 and in many other articles outside Wikipedia!

5.12.111.144 (talk) 20:22, 11 May 2016 (UTC)
 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. Izno (talk) 20:27, 11 May 2016 (UTC)

propulsive efficiency
This article introduces propulsive efficiency in the context of 'normal' forward flight, as does the source quoted. I'm not aware of any other use of the term. Looking at the propulsive efficiency plots, I would expect any reader to ask "what's the physical meaning of the red line at 100%?" In the absence of an explanation I have closed the loop with the statement from a reliable source.Pieter1963 (talk) 20:46, 3 June 2016 (UTC)


 * Do you really think it's a good idea to summarise reliable source material in a way that is obviously incorrect?GliderMaven (talk) 15:42, 4 June 2016 (UTC)


 * Please note that I haven't summarized anything. The source says "Propulsive efficiency is equal to unity when the effective exhaust velocity is equal to the flight velocity. This case has no physical meaning because, in this condition, the thrust is zero (no momentum change)."
 * Please add extra explanation to the article if this sourced statement is incorrect by adding your own sourced explanation so all readers can learn from it.Pieter1963 (talk) 20:36, 4 June 2016 (UTC)


 * The statement ("this case has no physical meaning") is not incorrect, it is just highly subjective and has no encyclopedic value. The point is not whether a "case" has "physical meaning" but only to point out that for a finite mass flow, a propulsive efficiency of one can only be reached when the thrust becomes zero. Let us focus on that, and abandon needlessly controversial statements. Ariadacapo (talk) 08:54, 11 June 2016 (UTC)


 * Good pointPieter1963 (talk) 20:29, 12 June 2016 (UTC)

Water jet
... out of two nozzles, mounted on a rigid backpack can lift a person some meters high over a water surface. Is a kind of sport. One may speak of a water jet but maybe not of an engine.

See further Segner wheel (jet but no engine).

--Helium4 (talk) 17:06, 21 July 2016 (UTC)


 * Perhaps you can argue that in that case, but the article links to jetboat which seems far less controversial.GliderMaven (talk) 17:58, 21 July 2016 (UTC)

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Spooling up
Could someone add something about the term "spooling up" (even though it's not an "official term"). I came to the page after being redirected for a page about spooling; it mentioned about its use re jet engines, but a search for the term revealed nothing on this page. Thanks. — Preceding unsigned comment added by 146.198.113.70 (talk) 17:53, 8 March 2017 (UTC)


 * The term 'Spooling up' refers to the increasing rotational speed of the engine when the throttle is opened, and in effect, the time lag in the engine reaching the intended throttle (power) setting after the movement of the power control.


 * Similarly, 'Spooling down' is the decreasing rotational speed when the engine is changed to a lower power setting. Jet engines, to a greater extent than piston engines, take time to follow the throttle setting, i.e., take time to alter their rotational speed, to accelerate/decelerate, in line with a changed throttle setting. — Preceding unsigned comment added by 95.149.241.93 (talk) 18:52, 26 May 2017 (UTC)

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"Turbofans are the dominant engine type for medium and long-range airliners."
I understand this statement is true. Yet the reader may wonder what engine types are used in short-range airliners. Could someone please add a remark to clarify this?

Thanks! Sucramy (talk) 07:25, 18 June 2017 (UTC)

So where is Rolls Royce?
I landed on this page because I have been studying the history of Rolls Royce Jet engines.

The article mentions Power Jets Ltd, which produced the prototype engines for the Gloster Meteor, but this small company was not capable of large scale production. Attempts to team up Power Jets Ltd with the Rover motor company failed, and the designs eventually passed to Rolls Royce, who enhanced whittles designs with technology levered from supercharger designs in conventional aero engines. This led to the Rolls Royce Welland which was used for production of the Meteor.

As far as I can make out this was in production before the Jumo 004, which would make it the first production jet engine (The Jumo appeared earlier in prototype form but was delayed for some time before entering into production).

The Welland was superseded by a variant called the Derwent, which was used on later Meteor models and on other aircraft post war until the arrival of reliable axial-flow engines in the 1950's.

It seems to me incredible that they apparently do not exist in this 'history'. — Preceding unsigned comment added by RogerIrwin (talk • contribs) 23:53, 16 June 2017 (UTC)


 * There are articles here:


 * Power Jets
 * Rolls-Royce Welland
 * Rolls-Royce Derwent


 * Feel free to add something from these to the article. — Preceding unsigned comment added by 95.150.11.183 (talk) 11:44, 21 June 2017 (UTC)

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Semi-protected edit request on 4 January 2018
Currently under the sub heading of: Energy efficiency relating to aircraft jet engines

The first paragraph has this sentence:

"It includes mention of inlet and exhaust nozzle losses which become increasingly significant at the high flight speeds achieved by some manned aircraft since only a small proportion, 17% for the SR-71 powerplant and 8% for the Concorde powerplant, of the thrust transmitted to the airframe came from the engine."

This is worded so poorly (IMO) that I am unable to discern what they intended to say. If only 8% of the thrust of the Concorde came from the powerplant, from where did the other 92% come?! It certainly looks as if they stated it the losses (17% and 8%) differently than the later referenced "thrust transmitted to the engine". This is my guess of what they intended to say:

It includes mention of inlet and exhaust nozzle losses which become increasingly significant at the high flight speeds where the thrust transmitted to the airframe by the engine is notably reduced (by 17% for the SR-71 and 8% for the Concorde). Shooky56 (talk) 15:09, 4 January 2018 (UTC)
 * Yes check.svg Done The sentence is question has been removed as gobbledygook.  Spintendo  ᔦᔭ   07:38, 5 January 2018 (UTC)

Production propfans?
The Propfan section currently says "While significant research and testing (including flight testing) has been conducted on propfans, none have entered production" (emphasis added). However, it seems that the Progress_D-27 has at least seen some degree of production, being employed on the An-70 transport. Should I update the article to reflect this fact? — Preceding unsigned comment added by Theunamedguy (talk • contribs) 23:42, 29 May 2018 (UTC)