Talk:Yakovlev Yak-18T

Source of spec info
I'm not sure where the spec data comes from but that is not the standard engine. So the rest of the info is suspect. Paul Beardsell (talk) 05:02, 29 November 2008 (UTC)

I have now replaced the data with info from the unofficial translation of the flight manual and provided the ref. Paul Beardsell (talk) 12:23, 29 November 2008 (UTC)

And the performance data is mostly rubbish! If I fly my 18T light, low fuel, one up, with or without flaps, I can't get the stall speed that low. 101 km/hr? Never. And the stall speed is usually quoted at MAUW. Other figures similarly suspect. 92.147.38.18 (talk) 06:22, 27 May 2011 (UTC) Ah, that was me: Paul Beardsell (talk) 06:23, 27 May 2011 (UTC)


 * All the performance data other than the stall speed comes from Brassey's World Aircraft & Systems Directory 1999/2000 - a high quality reference compliled by a well known aviation writer who in past past was responsible for large chunks of Jane's All The World Aircraft - I have checked the performance specs against those quoted Jane's All The World's Aircraft 2003–2004 and apart from the Vne, match pretty closely. The stall speed is from which quotes a range of stall speeds of between 100 and 123 km/h depending on the weight and power settings - Jane's quotes 125 km/h as a landing speed.Nigel Ish (talk) 15:50, 27 May 2011 (UTC)


 * The universal convention is to quote stall speeds at MAUW with least favourable CoG (i.e. usually at forward limit) at 1G clean Vs or dirty Vs0 and this is what we should do here. Paul Beardsell (talk) 08:58, 4 February 2013 (UTC)


 * The aircraft flight manual or pilot's operating handbook should trump any other reference in almost all cases esp. when it comes to reporting performance figures. Where else do Janes or Brasseys get their data? Hangar chat? Brasseys is usually wrong if it contradicts the POH. Paul Beardsell (talk) 09:09, 4 February 2013 (UTC)

Still in limited production
No it is not. The production of new aircraft has been zero zero zero the last 13 years. There is no factory. I am removing that claim. Paul Beardsell (talk) 09:15, 4 February 2013 (UTC)


 * I added that based on the cited ref Bayerl, Robby; Martin Berkemeier; et al: World Directory of Leisure Aviation 2011-12, page 170. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X which says that the "Yak-18T remains in small scale production" and lists the manufacturer as AS Yakolev Design Bureau. The ref only lists current production aircraft, as of the publication date of 2011. It is possible that the production consists of something as simple as hand-assembly of new Yak-18Ts from existing stocks of parts on an "as ordered" basis. The article text further down still reflects that, so unless you have a ref showing that this ref is wrong I would suggest that the text in the infobox be restored. - Ahunt (talk) 11:29, 4 February 2013 (UTC)


 * Your response is understandable and was anticipated but it reveals a typical Wikipedia problem and I'll return to discuss that in a minute. However, addressing the *facts* of the matter directly first:


 * There are those who would like you to believe the Yak-18T is still in production. At about the time I bought mine, just a few years ago, there was a rumour that several dozen had been ordered in a new batch. This was reassuring to me, and whereas I am not sorry I bought my aircraft, there was no truth to the rumour.


 * Similarly it was once possible and may still be so that somewhere on Yakovlev's web site or elsewhere related you may find the claim that you can order a new 18T. I tested this. You cannot. You can order a batch of new 18T's at phenomenal unit cost.


 * I believe my 18T was just about the last assembled of the second series, in 1999. It would have been assembled as you describe, from batches of parts left over from the original series one production. The series two aircraft were very limited in number.


 * There is no longer an 18T assembly line, or a factory where 18T assembly could quickly be established. It is by no means certain that all the jigs exist.


 * The M14P engine is almost impossible to manufacture new anymore. Some castings can no longer be made. You can however still just about buy a "new" M14P, but the lack of engines problem is one of the reasons the 18T cannot be produced.


 * By your criteria the Tiger Moth is still in production. Indeed, many more "new" (by your definition) Tiger Moths have been manufactured in the last decade that 18Ts. New 18T production in the last 10 years: Zero. Tiger Moths: Several. Wikipedia does not say the Tiger Moth is in production.


 * The legal status of the 18T has been in hot debate at times over the last 10 years. Over ten years ago Yakovlev disavowed responsibility for the aircraft. For an aircraft to have a certificate of airworthiness there needs to be a manufacturer who takes responsibility for the type certificate. There is no such body for the 18T. It follows as a necessary consequence that no one is able legally to manufacture the aircraft.


 * Paul Beardsell (talk) 12:30, 5 February 2013 (UTC)


 * Your arguments here make a lot of sense and certainly there are manufacturers who will claim that an aircraft type is still in production when it is not for marketing or even pride reasons, and could have reported that to the World Directory staff, because they print what the manufacturer says. These sorts of claims are very hard to independently verify, especially in Russia. That said, as you know Wikipedia is based on verifiable reliable refs and right now all we have is one 2011 ref that says it was in limited production at that time. If we are going to say anything different we really need a new ref that says it is out of production. As a compromise how about we state that "the manufacturer claimed in 2011 that the aircraft was still in limited production although none had been produced for some time" or something similar. At least then we would be going with the refs we have while being reasonable about the doubt factor. - Ahunt (talk) 12:44, 5 February 2013 (UTC)


 * I have incorporated that, please see my comment below. - Ahunt (talk) 12:52, 5 February 2013 (UTC)

Dodgy references
One can find references on the Web and in books that say the 18T is still in production. One cannot easily find references that it is not in production. The aircraft is however not in production. Zero new aircraft have been manufactured in the last ten years. One cannot order an 18T from its manufacturer. There is in fact no legal manufacturer as the original manufacturer refuses to support the aircraft and there is no other holder of the type certificate. What therefore to do on Wikipedia? By the rules we should reflect what others are saying, we are not a primary source of knowledge, and therefore this encyclopedia cannot represent the facts if these are not easily established by citable reference.

Well, I can tell you what we can do: We can represent what others say in a way that reveals the facts of the matter. And we can also neglect to repeat that which we know not to be true. I am *not* advocating that we say in the main 18T article that "the aircraft is not in production" - I am merely suggesting we neglect to say "the aircraft is in production".

What say you? Paul Beardsell (talk) 12:41, 5 February 2013 (UTC)


 * Given the one ref that says it is in limited production and the degree of quite reasonable doubt you have cast here, how about then we leave the infobox blank as it is now and I fix the text to indicate that it being in production is a claim only? - Ahunt (talk) 12:47, 5 February 2013 (UTC)


 * Just as a proposal I have made that change to the text under "Operational history", see what you think. - Ahunt (talk) 12:51, 5 February 2013 (UTC)


 * I agree with the text as written. However, putting the WP-purist hat on, there is an appearance now that the reference you found supports the assertion that zero aircraft have been manufactured. If you separate out the cited material from the assertion zero were actually manufactured then this is more correct. We do run the risk then that someone asks for a reference to support that. It will be difficult to do so for the general reason it is difficult to prove a negative. Therefore by WP rules the zero newly made claim would have to be removed. And that returns us to where we were yesterday. A "correct" article representing a falsehood. Hence my preference just to remove the 2011 reference entirely. It adds nothing save the falsehood. Paul Beardsell (talk) 13:04, 5 February 2013 (UTC)


 * Good point, let me shift the ref so that it covers the text actually cited. That will leave the tail of the sentence uncited, but we can refer people here to discuss if that is deemed a problem. - Ahunt (talk) 13:24, 5 February 2013 (UTC)


 * Thanks. Paul Beardsell (talk) 13:48, 5 February 2013 (UTC)

I anticipate the World Directory of Leisure Aviation says, in next edition, that zero aircraft were actually manufactured. They won't be clear as to where they got that info, but they would have got it here. This article at Wikipedia will then be able to cite that as reference. :-) Paul Beardsell (talk) 13:52, 5 February 2013 (UTC)


 * LOL, WP:CIRCULAR applies! - Ahunt (talk) 14:05, 5 February 2013 (UTC)