Talk:Nutating disc engine

Oil, seals and other such facts of life

The NASA report 214342 mentions that the running time of the engine was brief in order to minimise wear. Figure 4 shows a quite incredible array of seals. How are these things lubricated? Greg Locock (talk) 22:07, 31 December 2007 (UTC)

The Mcmaster engine runs on pure hydrogen (OK) and pure oxygen. Have you seen what an oxygen bottle looks like? Have you tried to get one shipped by road or plane? How much of the weight advantage of the engine will be lost in providing a crashprroof O2 cylinder? Greg Locock (talk) 09:46, 1 January 2008 (UTC)

Use of bold

Do we really need to use bold to emphasise the phrasing in the article? It's a little patronising...Dick G (talk) 05:20, 12 December 2007 (UTC)

Patent number

The patent number listed in the article is wrong. The article lists patent number 85619, which is for a manure spreader from the mid-1800s. However, patent number 5,251,594 for a "nutating internal combustion engine" was issued to a Leonard Meyer of Illinois. Could someone more knowledgeable check that this is actually the device referenced in the article? —Preceding unsigned comment added by 209.94.128.86 (talk) 05:54, 12 December 2007 (UTC)

See this too. That page suggests that the patent application number was 85619, but that the US patent number itself is 5482449. Confused? Carre (talk) 09:00, 12 December 2007 (UTC)

5,482,449 is a patent for a nutating disk compressor. 5,251,594 is for a nutating disk internal combustion engine. I have donloaded the patent document (pdf) for the engine from the US Patent and Trademark Office. This is the primary source for the device and should have been cited in the article. Since, although it is in the public domain, the USPTO charges a copying fee ($3), I think I would like to provide this document to Wikipedia. Would it be appropriate to upload it to Wikisource? It is 36 pages long.

To change the topic slightly, I have noted that the administrators insist on sources for articles, but do not seem to be able to differenciate between sources on the basis of quality. Inferior citations are frequently allowed, when better ones could be found with a little effort. Too Old (talk) 02:08, 13 December 2007 (UTC)

Are not patents primary references, and therefore not permitted as sources? Since most patents are non-notable, little can be used of this information beyond the patent number anyway, which is little more than pointless trivia.NiD.29 (talk) 01:56, 22 August 2012 (UTC)

Power/Weight ratio comparison

The proposed study power ratio estimation for this engine is compared to the Graupner G58 and Desert Air DA 150, which are both high performance two-strokes model engines. I think comparing them to an engine designed for relatively high reliability and low consumption is not fair nor pertinent. For carrying high cost electronic and systems in rugged environment, do you use two-strokes designed for model competition ? In addition to the fact that this might be the first generation of this kind of engine, the estimation looks promising. Realisation shall tell but the comparison shall be done against other kind of engines, more in line with the purpose of the project.You have the choice, aside automotive engine, in engine in development you have the zoche aero-diesel, the Revetec or others studies on light aircraft engines. -PRZ- —Preceding unsigned comment added by 86.67.23.60 (talk) 12:25, 22 November 2008 (UTC)

Whoa thar, both those engines are being used to power UAVs, the proposal for this engine is to power UAVs. So why is it not a fair comparison?Greglocock (talk) 21:35, 22 November 2008 (UTC)

Nutating?

Why the note to not link? Nutating is not likely to be known by most visitors (wobbling is perhaps more appropriate anyway). Images illustrating the pertinent parts and their motion would be really handy here as well.

I also fail to see why the page should be named for the latest iteration, rather than the originator of the idea?
"Dakeyne engine" would be more appropriate - it is known and has supporting references, while "nutating" seems to be the result of a thesaurus search made for the purpose of differentiating his largely similar copy, while the page remains little more than advertising for his unsaleable idea with a few whoas! patched on.NiD.29 (talk) 02:25, 22 August 2012 (UTC)

Please, read talk: Nutation. In short, there are two completely different types of mechanical motion, called "nutation" by different sources. One (historically, the nutation) is related to rigid body dynamics and constitute a special movement of the rotation axis. Another is actually a kind of precession and, possibly, will be described separately (under the proposed name nutation (engineering)). There is also wikt: nutate article. Incnis Mrsi (talk) 15:21, 22 August 2012 (UTC)

Just did - thanks for bringing that discussion to my attention - that is no reason not to link that page though, rather that the intro there needs to describe both types of motion clearly, rather than burying the engineering part at the bottom of the page with no previous mention of it as if it was irrelevant. In the meantime might I suggest we link to the individual section as in... [[Nutation#Mechanical engineering]] then if the page is split, the link can be updated as required (with a note there to that effect).NiD.29 (talk) 18:06, 22 August 2012 (UTC)

It is exactly a "link to the individual section" what is discouraged by WP:MOSLINK, because of maintenance issues. Think about a (temporary) redirect page, or, better, make a stub at last. Incnis Mrsi (talk) 01:14, 23 August 2012 (UTC)

I have tweaked the intro so it is a bit clearer, and created a temporary redirect (mentioned in a comment on the target page) pending a rewrite of the Nutations page.NiD.29 (talk) 12:06, 23 August 2012 (UTC)

Compression?

In the animated diagram, there is no compression that I can see. For the top half, when one part of the disk goes up, the other side goes down, so the top half has constant volume. Likewise for the bottom half. So "A portion of the area of the disc is used for intake and compression." seems inaccurate at the very least. Could it be referring to a slightly different type of nutating engine? If so I'd love to see it, but sadly even youtube seems to have no animations of this thing. DrZygote214 (talk) 14:46, 24 August 2014 (UTC)

As the disk's motion pushes the gas around the central axis, the nutation (not rotation) results in the difference in pressure, as the gas/fluid is unable to keep up with the rising disk, resulting in an area of low pressure there (allowing intake to work), and an area of high pressure where the disk is descending (the exhaust). The faster it is able to nutate, and the more resistance the operating fluid has to moving, the greater the possible compression. It wouldn't work with water or hydraulic fluid as they are only marginally compressible, but with a gas or compressible liquid it would work just fine. Not sure about the text description though, at best it should be rewritten to be comprehensible to a layperson. (As I understand it anyway)NiD.29 (talk) 01:30, 26 August 2014 (UTC)

So you're saying that the halves do indeed have constant volume, but the motion of the disk itself produces a buildup of pressure on the leading side and a reduction in pressure on the trailing side? That would make perfect sense to me because a wing does pretty much the same thing. However, there's no way this differential pressure could match the compression ratios of a traditional piston and cylinder, unless the disk was nutating super super super fast, I mean uber-high RPM's (if we can use RPM for nutation). So is this why the nutating engine is not viable after all? That would be too bad because it's rather ingenious to see an engine with, fundamentally, only one moving part. DrZygote214 (talk) 21:51, 26 August 2014 (UTC)

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@Jim1138

you erased last night an new animation of a nutating piston machine in less than a minute in the middle of the night. Congratulation! You are certainly the fastest eraser to protect Wikipedia from any scientific knowledge. Is a patent office a reliable source for you? You could had ask for this, but you shoot first and ask questions later… Ergo I ask the community first: should the following animation included in the article or not?

Nutating piston engine

Another nutating piston engine (patent DD113788; DE2519911A1) has been invented and developed by a German Physicist. The two stroke engine has direct lubrication and an unsymmetrical control diagram.

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  Nutating piston engine