Talk:Jet engine performance

Error in worked example

Gross thrust calculation has to be wrong:

The expression w8 * V8 / g doesn't have the right dimensions. Since Cx is withou dimension, the dimension of w8*V8/g has to be mass*distance/time^2 (=force), but w8*V8 is already mass/time * distance/time = mass*distance/time^2, so multiplying by g gives incorrect dimensions.

I suspect there is some confusion about lbf (pound force) and lb (pound mass) somewhere causing this. If we assume the worked example yields the correct result, I would guess that the expression for V8^2 is also wrong, with the two errors cancelling each other out. Either that, or the result of the worked example is wrong. Avl (talk) 13:28, 17 June 2017 (UTC)

Technical

Disagree. It probably needs a less technical, more explanatory, introductory para, admittedly, but the devil is definitely in the details. Greglocock 07:27, 31 December 2006 (UTC)

The article needs to quote its sources (or at least _some_ sources!). The nomenclature appears fairly complete, but the article is long, and not everyone can have two copies up at the same time. So, also reference new and/or obscure variables at first occurence, please. Bob aka Linuxlad 11:19, 15 January 2007 (UTC)

Fair use rationale for Image:Slamacceleration.gif

Image:Slamacceleration.gif is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Wikipedia:Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

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BetacommandBot (talk) 05:42, 24 January 2008 (UTC)

Fair use rationale for Image:Slamaccelerationchic.gif

Image:Slamaccelerationchic.gif is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Wikipedia:Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images lacking such an explanation can be deleted one week after being tagged, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 05:43, 24 January 2008 (UTC)

Oh My God

This article is just too much gibberish and not a single explanation. I'm just confused, this needs some heavy editing (I don't do it because i don't know nothing about this)--MakE ^shout! 18:48, 14 November 2008 (UTC)

Deletion

This article is at risk of being deleted. See comments at Wikipedia talk:WikiProject Aircraft/Engines#Jet engine performance.

Effort will be required to resuscitate the article by removing inappropriate information, adding appropriate encyclopedic information, adding references and in-line citations. Dolphin51 (talk) 02:31, 1 May 2009 (UTC)

As the person who proposed the deletion, I'm glad to see someone taking an interest in improving the article. I'm not an over-eager AFD wonk! I know it's long, and will require a lot of work. Unfourtunately, the subject batter is beyond my knowledge, and I don't have access to texts on it anyway. I can help with some of the other editing tasks, when nheeded. As long as it is being worked on and improved, I'm not going to take it to AFD. Hopefully some other editors with a knowledge of the subject can step in and help out. One suggestion is to drastically cut the article back to only what can be sourced in the next few days, and then work from the history and add sections as you and others find sources for that info in later weeks. - BillCJ (talk) 02:54, 1 May 2009 (UTC)

Agreed. I will let you know when I have finished. Dolphin51 (talk) 03:04, 1 May 2009 (UTC)

Wikipedia is not a text book. I see no purpose for any of the original text in this article. I intend to delete all the text, leaving only my new introduction and my reference. Once I have done that, I would appreciate someone else re-assessing the quality of what is left and deciding whether it is a stub or start class, and making the necessary change to the quality banners at the top of this Talk page

Next, we can begin re-building the article with encyclopedic material that can be supported by references and citations. Dolphin51 (talk) 03:15, 1 May 2009 (UTC)

I've just reverted your massive vandalism by deletion. When an article is up for AfD is not an appropriate time to delete most of it! That material might well disappear, most likely it will do so gradually and for the basis for a careful re-working of the article in a clearer form. Whining "Math is hard!" and deleting the majority of an article because you don't understand it isn't acceptable. Andy Dingley (talk) 09:39, 1 May 2009 (UTC)

Wow! This was not "vandalism" in any way, form or fashion. Please be careful with such accusations. The unreferenced header, which has been there over a year, states: "Unsourced material may be challenged and removed." Consider it challenged and removed. The article itself has not been deleted, only the unreferenced content. Dolphin has taken to the time to try to give references for some of the article, and that is commendable, and the way to do it. The unreferenced text is still available in the history, and Dolphin has commited to try to work on that in the coming weeks. What is even worse, though, is that you actually removed his references in your reversion. While I would not call that vandalism either, it certianly is unhelpful. Also, the article has not been AFDed yet, so that restriction does not apply in this case. I've agreed to give Dolphin the time to work on the article before taking it to AFD, but if the previous UNSOURCED content is re-added again, I will consider taking it to AFD immediately on those grounds. - BillCJ (talk) 21:12, 1 May 2009 (UTC)

transwiki

All revision of this page have been transwiki imported to v:Jet engine performance. --mikeu ^talk 13:24, 30 June 2009 (UTC)

Clean up the tattered remains

Since this article was transferred to Wikiversity long ago I suggest the title be deleted completely from Wikipedia. Whilst it remains it misleads readers into thinking it's the best Wikipedia contributors can do. We know it isn't when we realise the original contributor's work is in Wikiversity.Pieter1963 (talk) 00:32, 14 March 2014 (UTC)

Are you saying the original version now at Wikiversity is better than the present version on Wikipedia, or vice versa? Dolphin (t) 01:40, 14 March 2014 (UTC)

In what way is the Wikiversity article any better? It has gained a section of unsourced twaddle on engine sizing, but nothing else.

As a separate issue, the Wikiversity project should be closed itself, as a failed project and now little more than a home for MADEUP kook-science.

I've restored this encyclopedic (albeit poor) article to the encyclopedia, where it belongs, and raised it at AfD as BillCat insists. Andy Dingley (talk) 10:44, 14 March 2014 (UTC)

And the AfD has just been closed already, so nothing is resolved at all and we're back to 2009. Well that was worthwhile. No wonder no-one except the clique will work on aircraft topics. Andy Dingley (talk) 21:52, 14 March 2014 (UTC)

"Are you saying the original version now at Wikiversity is better than the present version?" Yes.

The wikipedia version a few days ago consisted of just a short piece on "thrust" under the heading "Jet engine performance". This is similar to "The human body" just having a short piece on the "hand", or "The solar system" just having a short piece on "the moon".All 3 would be attempts on topics that merit a lot more.

Now, in support of the re-instated original version as it stands today...

"This article does not cite any references or sources." Yes it does. It has a reference to the Kerrebrock book. And this is all it needs IMO.

"This article needs attention from an expert on the subject." It was written by an expert. It doesn't need any more attention from experts.

"This article may be too long to read and navigate comfortably" This article is not meant for the casual reader nor man-in-the-street. It is meant for the serious reader, or in the author's own words "I consider the article to be of value to students of Aeronautical Engineering". I don't think we should deny the serious reader access to this information just because it does not contain in-text references. Note that it does have the all-encompassing Kerrebrock reference.

"In what way is the Wikiversity article any better?"It has to be better simply because it was written by, I suspect from it's content, a performance engineer who wants to share with us some of what he uses in his day-to-day work of helping design and develop jet engines. Threre is alot of interesting stuff in there. This is of value to someone wanting to follow in his footsteps or just someone who wants some insight into what jet engine performance is.

"a section of unsourced twaddle on engine sizing". I did not spot anything that would fit my decsription of twaddle as it's all stuff that's used every day by performance enineers. Even Stanley Hooker, when he returned to Derby in 1967 to help sort out the RB211, had to use this "twaddle" when he discussed with the 211 performance department how to raise the thrust from an unacceptable 34,000 lb to 43,500lb. It's in his book "Not Much of an Engineer" P189-191.

"MADEUP kook-science"Frank Whittle used it as well as Stanley Hooker.

"encyclopedic". Not so. There is a book titled "Jet engine performance" with 646 pages.

"albeit poor". I'm sure Frank Whittle or Stanley Hooker wouldn't have given it the thumbs-down and neither am I for what it's worth.

Summing up. I get the impression that no in-text references is seen as proof that the content is questionable. This is very definitely not the case with this one. However, if it is a wikipedia rule that all articles have in-text references "to prove" they are solid stuff then you have no alternative but to delete it all because no-one in 4 years has come forward as able and willing to conform.Pieter1963 (talk) 14:57, 15 March 2014 (UTC)

I have added some references. What's the next step?Pieter1963 (talk) 18:46, 15 March 2014 (UTC)

Time to move forward

This article now has references added and a positive appraisal from someone with a geuine interest in the subject matter of the article. Whilst the article may not be to everyone's taste I believe it should be recognised as a valuable addition to wikipedia(It answered a couple of long-lingering questions for me). Perhaps a stumbling block is it being subject matter that pays wages/salaries rather than of purely hobby or intellectual interest. If anyone is adamant it needs changes in line with wikipedia guidelines/suggestions please make specific demands which can be considered by anyone prepared to follow them up.

I believe it is time to remove the "multiple issues" header block from the article.Pieter1963 (talk) 13:38, 17 March 2014 (UTC)

I have expanded the introduction to explain what jet engine performance is and to address the concern on difficulty navigating.

I see no value in adding more references as the entire content is standard engine engineering.

I see no reason to move it to Wikiversity. I was pleased to find it where it is.

I have removed the multiple issues header.

Removed years-old too technical header. Best start afresh if still perceived that way.Pieter1963 (talk) 18:53, 19 March 2014 (UTC)

Multiple issues header

"This article.. ..may not reflect the encyclopedic tone..." It follows the tone used by reliable sources so must be ok. The header is too vague. Any feedback has to be specific with examples to give anyone a fair chance at responding.

" written like a manual or guidebook" If the no-textbook rule has to be followed then move article to Wikiversity. If it doesn't need to be followed then it doesn't need the header.Pieter1963 (talk) 21:17, 9 May 2016 (UTC)

Delete article from Wikipedia?

This article has a 'multiple issues' tag. I think there are 2 options if we want to action the tag, ie delete from Wikipedia as is already in Wikiversity or remove 99% of it so tag is no longer relevant. Any comments? Thanks Pieter1963 (talk) 17:27, 25 April 2023 (UTC)

First, a short history from my perspective. See Deletions above.

On 29 April 2009 BilCat proposed the article for deletion. See the diff. Discussion took place on the Talk page - see Deletions above.

On 1 May 2009 I erased the offending text which reduced the size of the article by 50,788 characters! I began working on a new version of the article - one that would meet Wikipedia's standards. I inserted my new text on 9 July 2009 - see the diff.

On 14 March 2019 2014 Andy Dingley restored the original version of the article (increasing the size of the article by 49,509 characters.) Andy then immediately nominated the article for deletion - see the diff. On the same day Northamerica1000 cancelled the deletion nomination as a "speedy keep" decision.

The article has remained substantially as the version that was proposed for deletion twice - once by BilCat and once by Andy Dingley. My 9 July 2009 version has never been restored despite it having been created as a means of eliminating the myriad problems that existed, and saving the article from deletion.

Are you familiar with the version that existed immediately prior to 14 March 2019 2014 when Andy Dingley restored the discredited version in order to get the article deleted? If not, please have a look at it and let everyone know what you think of it. Dolphin (t) 02:57, 26 April 2023 (UTC)

I stopped watching this page long ago. BilCat (talk) 03:43, 26 April 2023 (UTC)

Yes Dolphin, that is very much a short history from your perspective. Andy Dingley (talk) 10:03, 26 April 2023 (UTC)

I don't know my way around well enough to find the version immediately prior to 14 March 2019. My "view history" jumps from 17 Oct 2018 to 24 Aug 2019.Pieter1963 (talk) 20:23, 27 April 2023 (UTC)

My mistake! My mentions of 14 March 2019 should have nominated the year as 2014, not 2019. Sorry. Dolphin (t) 23:18, 27 April 2023 (UTC)

It still has university stuff like enthalpy. I have an idea which gets round all the so-called mumbo jumbo and which may be acceptable. It will be a fresh start.Pieter1963 (talk) 23:00, 29 April 2023 (UTC)

I will be pleased to see your idea for a fresh start. Please go ahead. Dolphin (t) 23:07, 29 April 2023 (UTC)

Another week should just about do it Pieter1963 (talk) 13:43, 25 May 2023 (UTC)

Replaced entire previous content with new from a more basic perspective.Pieter1963 (talk) 21:37, 14 November 2023 (UTC)