Talk:Napier Deltic

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Hmmmm... Everything2 articles are copyrighted isn'it ? Ericd 15:03, 20 Aug 2003 (UTC)

Morven states that he is the author, so he can do with the article whatever he wants.—Eloquence 15:06, Aug 20, 2003 (UTC)

Yes—to clarify, the original uploaded revision was an exact copy of my E2 writeup on this topic and thus mine to release here if I wish. Morven 16:01, 20 Aug 2003 (UTC)

Sorry I've read to quickly I didn't see the "my". Ericd 16:49, 20 Aug 2003 (UTC)

No problem! I plan to add in some of my other E2 contributions in the near future. Morven 17:10, 20 Aug 2003 (UTC)

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Great article. I'm still confused on the basic design concept, though. A diagram would be a great help. Rossami 16:04, 24 Oct 2003 (UTC)

As always, a diagram would be a great help (when it comes to how things look, words can be cumbersome). Unfortunately all will be copyrighted and thus unusable here. I'm going to see what I can do to draw one. --Morven 16:27, 24 Oct 2003 (UTC)

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Would some of the manuals at http://www.intertrader.net/ptfdeltic.htm be in the public domain to copy for illustrations?

Oh, and is that last paragraph really NPOV?

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I am certain that German engineers attempted to design such an Engine before Napier tried. I understand the the Germans couldn't get it to work because they hadn't twigged that one crankshaft had to rotate the opposite way.

Animation Added (but wrong :-( )

I worked the cylinder timings out on paper, i hope this animation helps, ive managed to include the lag between exhaust valve and inlet valve and get everything running in phase. If anyone notices a fault i havent twigged to, please let me know, i had to remove the inside inlet manifolds for space reasons, but everything else is actually to scale. Emoscopes 22:21, 28 December 2005 (UTC)

The text quotes "in/out/in/out/in/out" tubing and rotaion symetry. And just common knowledge tells that symmetric engine would be more easy to handle. But alas the diagram shows non-symmetric engine with left bottom piston pair flipped against proper position. Alas original artist is no more active and i dunno if someone would be able to re-create the diagram. 85.90.120.180 (talk) 11:01, 30 August 2012 (UTC)

The engine isn't quite rotationally symmetric. Although the cylinder blocks and ports are, remember that the bottom crankshaft rotates in the opposite direction. Andy Dingley (talk) 11:51, 30 August 2012 (UTC)

I just added a more accurate animation. Doesn't show combustion process, but the phasing is now correct based on the Deltic Manual http://pigeonsnest.co.uk/stuff/deltic/deltic.html and a diagram in 'The Napier Way' http://www.ptfnasty.com/images/jpg/delticway/napier134.jpg. Shape and arrangement of parts based on this section http://www.craftsmanshipmuseum.com/images/ClenSection.jpg . This animation shows the engine as viewed from the FRONT (blower end). MigMigXII (talk) 08:04, 30 January 2013 (UTC)

2-stroke Diesel

It's a 2-stroke Diesel, however I have no idea how to introduce it the article. Ericd 22:38, 1 April 2006 (UTC)

What happened to the Deltic?

Fantastic article, especially the animation. I've got a few questions about the Deltic design which I'm chucking around in the direction of anyone who might be able to answer, however:

• Is a Deltic-type engine inherently inferior in power output to a four-stroke engine of the same displacement?
• Just how unreliable are Deltics? I've heard accounts saying they proved highly reliable and accounts saying they were constantly breaking down.
• Would a Boxer, or an X- H- or W-block engine of the same displacement be superior in performance?

Any help with these would really be appreciated!

My thoughts are not to think of the Deltic in terms of displacement, but in power to weight ratio. As a uniflow, 2-stroke, opposed piston engine, it lacks heavy cylinder heads and valve gear, and comparable 4-stroke arrangements are likely to be of a lower power to weight ratio. Emoscopes ^Talk 00:53, 27 April 2006 (UTC)

That's what I always thought - that the Deltic might well be inefficient, but that was the price you got for a light, compact engine that chucked out a lot of power. However, while I was trying to get some basis for comparison, I came across these (http://www.maesco.com/products/iveco/iveco_vector/iveco_vector.html) which I then compared with the engine description outlined here (http://www.55s.co.uk/ - Technical > Engines and scroll down). I'm no expert on diesel engines (steam is much more my thing), and thus I may well be comparing two engines that ought not to be compared at all; but as far as I can see, the Vector 40 produces more power, at a lower weight and with smaller dimensions, using an inherently more efficient combustion cycle. Even accounting for the advances made since the D18-25 was introduced (which, I admit, I have probably underestimated), I can't see how that's possible given the wisdom I've conventionally received regarding the Deltic. (By the way, I do apologise for the poor links and generally rubbish standard of formatting; Wiki's esoteric system is one with which I'm not exactly comfortable :))

1. Vector 40 - 16 cylinders, 40.16l, 1,440kw (1,930hp), 2,900kg engine weight - 0.49kW/tonne
2. DT18-25B - 18 cylinders, 88.2l, 1,231kW (1,800hp), 5,574kg engine weight - 0.22kW/tonne
3. DT18-37k - 18 cylinders, 88.21l, 1,709kW (2,500hp), 3,435kg engine weight - 0.50kW/tonne (http://www.ptfnasty.com/ptfDeltic2.html)

Some brief thoughts on this; the Deltic 25 was a rail deltic, and therefore was (as far as I know) derated for rail use and designed to produce 1,650hp continuously. The Vector 40 does not state a continuous rating, and fairs far more favourably with the Deltic 37 (marine deltic) in terms of peak power and weight. This place is a bit of a goldmine anyway; http://www.ptfnasty.com/ptfTechnical.html Emoscopes ^Talk 07:36, 28 April 2006 (UTC)

Is this accurate

A question re diagram in Napier Deltic/History. As I read the description all 3 cranks should each have an inlet and an exhaust piston. In that diagram, one crank has this, one has two inlets and one has two exhausts? —Preceding unsigned comment added by Dunheved1 (talk • contribs)

• Reply: Yes, you're right. I have added a note to the caption about it. The ports and timing of the left-hand cylinder are reversed.

http://www.ptfnasty.com/ptfDeltic.html states: "each crankpin carries one inlet and one exhaust piston". This of course follows from the fact that the bottom crankshaft's -60 degree phase difference cancels one of the others, leaving the remaining shaft's +60 degrees to be cancelled by the -20 degrees in each of the 3 cylinders in sequence. Thus the port order should be "ex, in, ex, in, ex, in", giving "lead, lag, lead, lag, lead, lag" going round the engine anti-clockwise from the bottom. 195.92.168.164 00:51, 22 August 2007 (UTC)

No, I believe that the ports & timing of the left hand cylinder are correct, based on that the bottom crank turns the opposite direction, as described in the text. The animation would seem to bear this out. --71.214.237.152 (talk) 19:42, 26 August 2010 (UTC)

No, it's incorrect. Read the refs, look at the photos on the linked Deltic gallery site. Andy Dingley (talk) 21:16, 26 August 2010 (UTC)

FYI

Since there seems to be some confusion, maybe this will be of some help. TREKphiler ^{hit me ♠} 14:09, 11 December 2008 (UTC)

Vibrations

The single set of three cylinders looks like it will have overall vibrations (twisting vibrations as well)

Can someone expand on how sets of cylinders were arranged to get rid (assuming they did) of these overall vibrations (as per 4 cylinder engines)

I don't see it in the article. Thanks213.249.232.187 (talk) 14:58, 6 April 2009 (UTC)

Something wrong with diagram or description

The animated diagram shows each adjacent connecting rod attached to the same part of of the crankshaft - therefor adjacent cylinders should be 60degrees out of phase with each other, additionally the article states that cylinder pairs are 20 degrees out of phase..

Therefore, starting with the bottom crank:

Bottom left cylinder part - angle A (eg the depth of the moving cylinder part is approximately cos(A) time the 'throw' or displacement)

Left cylinder (top cylinder part), lags bottom left cylinder part by 20degrees therefore its angle is A-20

Left top centre cylinder part (horizontal cylinder in diagram) is 60 degrees behind, therefore its cam angle is A-80 (80-A due to the geometry)

Right top centre cylinder moving part is 20 degrees ahead of left top centre cylinder part therefore its angle is is 80-A-20 = 60-A

upper cylinder part of rightmost cylinder cam angle is 60 degrees behind making the cam angle 120-A

bottom cylinder moving part of right cylinder is 20 degrees ahead of upper right cylinder part - so its cam angle should be A-100

But according to the diagram this part is on the same cam as the bottom left cylinder part and so should be at cam angle -(A-60) = 60-A.

different angles? whats going on?

As far as I can tell this won't work unless at least one of the cams has two angularly staggered parts for the different cylinders it attaches to.

Is it just that the diagram is wrong?213.249.232.187 (talk) 16:04, 6 April 2009 (UTC)

(If I've made an obvious mistake; don't waste your time attempting to explain it - I will triple check to see if I have made a mistake)213.249.232.187 (talk) 16:35, 6 April 2009 (UTC)

Questions

• How are the piston rods attached to each cam staggered so that the thing works - are all staggered by the same amount, or are they different?
• The animated diagram doesn't show any stagger - ?
• Where does the output come from - one of the crankshafts, or somewhere else.

Also the article repeats itself eg:

One of the interesting features of this engine was the clever way the crankshaft phasing was arranged to allow for exhaust port lead and inlet port lag. These engines are called 'uniflow' designs because the flow of gas into and out of the cylinder is one way, assisted by mild supercharging to improve cylinder exhaust scavenging.

Crankshaft connecting-rod journals were arranged so that each cylinder's exhaust piston 'led' its inlet piston by 20 degrees of crankshaft rotation. This allowed the exhaust port to be opened well before the inlet port, and allowed the inlet port to be closed after the exhaust port, which led to both good scavenging of exhaust gas, and good volumetric efficiency for the fresh air charge. It suffered from the disadvantage that the two pistons contributed unequally to power output.

I've removed the image until someone can clarify - I'm not sure it's correct. Specifically the angle of stagger on the cranks needs to be addressed, as well as the other missing information. Thanks.213.249.232.187 (talk) 20:03, 6 April 2009 (UTC)

Read the Boyle book - pp 134 -136. Also there aren't any cams - it's cylinder ported. Andy Dingley (talk) 21:25, 6 April 2009 (UTC)

The diagram's moving parts are right, but the positions of the inlet & exhaust are incorrectly swapped on the C bank (lower left). Conventionally the engine is usually drawn from the exhaust / turbo end, with A at bottom left, B on top and C at lower right, but this animation is from the other (gearcase) end. There's a nice photo of a partially dismantled T9 at the Deltic Preservation society, taken from the exhaust end.

Even so, I think it's worth leaving the animation in place until corrected. This is a minor point and the animation conveys a vital amount that can't be done easily otherwise. Andy Dingley (talk) 22:42, 6 April 2009 (UTC)

By "cams" I meant the things called "crank pins"

I'll look again at the engine animated diagram and see if it makes sense with the changes you mentioned.FengRail (talk) 22:53, 6 April 2009 (UTC)

I really think the image should be removed if wrong until corrected - it confused me - so it will confuse others.

I don't think the purpose of an encyclopedic article is to make readers attempt to reverse engineer a solution by providing incorrect info!

I still have a problem with the crankpins:

With the change of info you provided I still find something wrong - there must be a misssing piece of info - such as crankpins for adjacent cylinders being offset?

Starting with the cylinder that rotates in an opposite direction to the other two, and the cylinder connected to it with the exhaust port (manifold) nearest - I used A to describe the angle between crankpin, camshaft centre of rotation (X) and centre line of piston travel

So if the above angle is A, the angle (of crankpin-camshaft centre-piston centre line) on the opposite crank (Y), the same cylinder must be A-20 : because it lags by 20degrees as deccribed for 'uniflow' type operation in the article.

If the crankpin (on Y) on the for cylinder opposite to X is not angularly staggered with respect to the crankpin (on Y) for the other cylinder, then the angle it makes (as above) will be 80-A (addition of 60degrees)

The crankpin on Z (the remaining crank) for the same cylinder should lag by 20 degrees, therefor the angle is 80-A+20 = 100-A, and the angle for the crankpin (on Z) for the last cylinder will make angle 160-A (plus 60 degrees).

Therefor the crankpin on X for the same cylinder will be 20 degrees behind - ie at 180-A (160-A+20)

But if all piston rods shared the same position of crank pin this last angle should have been 60-A (from the difference between the first angle A and the internal angle of the triangle 60degrees)

So there is a deficit of (60-A)-(140-A) = 80 (180-A)-(60-A) = 120 degrees.

Surely this means the at least one crankshaft should have crankpins for opposite cylinders staggered by 80degrees (or the angle divided in some manner between the three)? MADE OBVIOUS MISTAKE - see below..

To try and explain it (without all the drawing and hand-waving needed to explain it), first note that the inlet/exhaust pairs are arranged in a circle of I-E-I-E-I-E. Also the crankpins are shared and each crankpin is driven by one exhaust and one scavenge piston. Fortunately the geometry doesn't care how many deltas there are (i.e. 6 for a T18, 3 for a T9).

Realise that they're _not_ a simple 60 degrees out of phase (from the delta geometry alone and assuming equally rotating cranks), that would be 120 out of phase.

Then the bottom crankshaft contra-rotates. This is the gimmick that allows a triangular delta engine, rather than the WW2 German square boxes.

(I had all this info)

To get any further you have to realise that there's no "TDC" for this engine, there are six of them for each delta 8-) Each piston has to be calculated separately, they don't all hit TDC together, nor even in pairs or triplets.

Yes took that into account - using the info in the article I assumed that the piston over the exhaust port reaches maximum "throw" 20 degrees of rotation before the opposite piston in the cylinder.

Now from the Boyle book, we describe the piston positions as Be, Cs etc. as their angle relative to TDC. Call the bank's angle T (obviously 60 degrees) and the exhaust lead angle q.

By definition, Be = Bs + q

From adjacent banks sharing a crankpin we see that, Bs = Ce + 360 - T

Some algebra with the geometry around the delta then leads us to Be = Be - T + 3q

thus q = T/3 or 20 degrees exhaust lead.

Andy Dingley (talk) 23:33, 6 April 2009 (UTC)

%^%^£^^ !!!

I had all the ports the wrong way round.. (or the all the cranks rotating in the wrong direction - ie 2 clock 1 anticlock instead of 1 clock 2 anticlock - depending on which way you look at it...)

This is why I say the article needs more attention - the direction of rotation relative to the position of the input ports needs to be clearly stated: It isn't currently and the erroneous diagram definately doesn't help.. (I speak from experience)

Also there's also the issue of how the vibrations of a planar three cylinder set are balanced out by grouping in multiples of three sets - I don't know this and to reverse engineer a solution would be WP:OR - specifically I imagine there is some simple angular relationship between each individual set of three (at a guess 120deg), also what are the lateral and rocking vibrations of an invidual three cylinder set, and are these vibrations cancelled out by grouping in 3s - I assume they are but don't know..

The output drive position would also be essential.

I don't expect you to provide this, (unless you can easily) - but the article definately needs these vital nuggets to not be an incomplete description.

Any more would be icing on the cake.FengRail (talk) 00:43, 7 April 2009 (UTC)

It's an opposed piston engine. Vibration's naff all to begin with, as apart from the small matter of exhaust lead, then each individual cylinder is already pretty well balanced. Combine this with a short, wide, and extremely stiff block of multiple rows and you have an engine where it's possible to model the vibration pretty easily (to do the wet-finger approach, just replace pairs of pistons with a virtualised "imbalance" piston, then treat it as a single-piston engine). Compare that to a hugely long V16 with a crankcase going all over the place and they hardly wobble.

The output drive is taken from the phasing gearbox and these varied between models. Early marine ones (mechanical drive) had a gearbox output in line with the AC (lower) crankshaft, those driving generators (both trains and boats) took it from the central phasing gear. The opposite side of this same central phasing gear drove a shaft between the banks to a mechanical blower (if fitted). The phasing gears were a central gear linking all three shafts, driven by a large gear (per crank) from the upper crankshafts or two small gears from the lower crankshaft, to reverse rotation. As the phasing gearcase was basically two huge flat aluminium castings only held together by bolts around the periphery, they weren't very stiff against end-loads. For that reason the phasing gears were straight-cut rather than helical. Phasing gearcases varied quite a bit between models. Some had a "central" gear that was below central (the upper idlers were noticeably bigger) so as to give a lower output shaft position. Locomotives with main & auxilliary generators had a lump at the top of the gearcase to drive the aux. generator.

In an article discussion that's still talking about "cams" and "piston rods", I can't see the justification for pulling the image though. At least re-draw a static one with the right manifolds and use that. Without anything, the whole article is impenetrable and worthless. It just doesn't make sense unless you can see the beast. Andy Dingley (talk) 01:05, 7 April 2009 (UTC)

(edit conflict) I may have a go at working out the vibrations for myself, as you describe calculating the 'virtual osciallator' equivalent to three pistons, and seeing if there is an obviously good way to balance any residuals.. I agree that the vibrations will be much less for a single three cylinder set than for a single or two piston inline engine (without balancing weights)

I'll see if I can contact the person who supplied the animation, and get them to correct it. I don't know how to do gif files and don't have the skill/software etc.

If the user has truly gone, then it should be possible to get a svg image made - which whilst maybe not a pretty, is considered better - since they are easier to display, and take up less memory/bandwidth. If nothing happens after a while I will make enquiries.

In the absence I'll try to dig up some diagrams from the net - at least they can be linked to if not directly inserted.

If you've got any referencable info, please add it. I can't really add second hand info without references..

I've made a list below of things for a good article (as a non exhaustive list) below for any editor with a lot of knowledge and spare time..

Also added the image you supplied as a link, luckily there is a link to animations of Deltics in the external links. Maybe the article should try to draw more attention to those in the absence of the image.FengRail (talk) 01:54, 7 April 2009 (UTC)

Expert attention

For a complete description the article needs:

• Accurate diagram (very desirable)
• Description of the direction of rotation of camshafts crankshafts relative to the position of the input ports needs to be explained.
• Vibrations of set of three cylinders
• How the vibrations of a planar three cylinder set are balanced out by grouping in multiples of three sets (if true)
  • and by extension phase difference between "crankpins" on camshaft. crankshaft
• Where the output stage - ie main driver or whatever it is called is located and how it is connected to camshafts. crankshafts
• also paragraph 5 and last paragraph of section "History and design" see http://en.wikipedia.org/w/index.php?title=Napier_Deltic&oldid=282249299 duplicate the same concept in part - so that could be combined.
• Any further information would be good, (but not essential) eg
  • Weights general
  • Build materials (steel?)
  • More info on how a high power to weight ratio is obtained - I understand that the absence of cylinder heads helps - but device requires 3 camshafts because of the lack of the heads - more details of how this fits together.
  • More info on expected time between failure/repair - this (alledgely) is an issue when used in diesel locomotives - figures for comparison with contemporary "normal diesel engine" would be helpful to prove/dispell this.
  • If above point is an issue - does the service life vary between marine/(air)/rail applications - ie do less 'forgiving' loads cause higher failure as found in (alledgely again) gas turbines.
  • rpm
  • emissions - comparison

And anything else. Only the intial points (singly indented) are necessary to make the "design" section acceptable.FengRail (talk) 01:34, 7 April 2009 (UTC)

You've got to stop talking about "crankpins on camshafts". Why is this article pulling _GOOD_ (albeit not perfect) animations that really did illustrate the key operating principles of a delta-layout uniflow engine, then using crass howlers like this? How are you expecting to have a serious discussion about vibration modes when you can't even tell a crankshaft from a camshaft? 8-( Andy Dingley (talk) 01:44, 7 April 2009 (UTC)

Sorry, corrected those. I'm not the expert..FengRail (talk) 01:52, 7 April 2009 (UTC)

Jumo 205

This entry should be linked to the Junkers Jumo 205 entry. Napier licensed the Jumo 205 opposed piston design and their only original contributon was the Delta configuration. The key to the original Jumo design was the 11 degree crankshaft offset to provide the vital scavenging timing.

The problem with the Jumo design is although at the point of ignition there is a potentially high thermal efficiency, harvesting the power needs 2 crankshafts etc. per combustion chamber. Napier's deltic design was an attempt to increase efficiency by having one crankshaft per combustion chamber. However, since all the crankshaft were linked, it was impossible to maintain the crucial 11 deg crankshaft offset that delivered the original Jumo power output per cylinder.Sageofabbott (talk) 13:41, 14 June 2009 (UTC)

tags without any specific complaints

quote "" air charge. It suffered from the disadvantage that the two pistons contributed unequally to power output. ""

i am not sure why this unequally should matter more here than in any other engine. why the tags without any specific complaints about the facts in the article. who and where are the wiki experts ??

Wdl1961 (talk) 04:05, 9 July 2009 (UTC)

Maybe they're too busy answering questions about camshafts and relational vibration?

As to the issue of piston power, then this is an issue (usually minor) for any opposed piston engine with lead between the pistons. A symmetrical engine like the Commer TS3 wouldn't notice it. It arises because the crankshaft torque due to each piston is the product of the pressure acting on the piston crown and the effective moment arm of the crank. Both of these change over time piston position / crank rotation, the pressure ramping up quickly and then falling slowly, the lever arm following a simple sine law. There's a peak in each of these curves and they don't coincide. To find the work done by each piston in total, integrate these two curves over an engine cycle (which is akin to finding the area of an indicator diagram).

If one piston leads the other, then the "degree of coincidence" of these two curves varies between the pistons. The curves are the same, and the integrated total work for each piston ("power" if you must) is relatively similar between them. However their peak torques can be significantly different, just because the two curves are shifted relative to each other and one piston lines up the peaks more nearly than the other does. It's an issue for vibration (sometimes), an irrelevance for output power over time. Andy Dingley (talk) 16:08, 9 July 2009 (UTC)

all of he above is true but is it interesting enough to most readers with or without further refs or discussion. you certainly have a good insight of the different relationships and lots of articles could use your attention.Wdl1961 (talk) 16:36, 9 July 2009 (UTC)

Incorrect image removal

http://en.wikipedia.org/w/index.php?title=Napier_Deltic&diff=308686029&oldid=306241775 The image has already been shown to be incorrect (see Talk:Napier_Deltic#Something_wrong_with_diagram_or_description - why was it re-added? 83.100.250.79 (talk) 14:07, 18 August 2009 (UTC)

Read the talk page above. Andy Dingley (talk) 14:14, 18 August 2009 (UTC)

there is nothing wrong with the animated image. Wdl1961 (talk) 15:10, 18 August 2009 (UTC)

There is something wrong with the image (ports are swapped in one bank), but I'd suggest that it still usefully illustrates the overall principle and we're better with it than without it. Obviously if anyone with the requisite skills & time (maybe the original author) could fix this, then that would be the best of all worlds. Andy Dingley (talk) 16:35, 18 August 2009 (UTC)

sorry i do not see which bank is wrong .left, right, upper? tell me i am curious.Wdl1961 (talk) 17:15, 18 August 2009 (UTC)

may i suggest to put a piece of paper on the figure and look only at one bank at one time. Wdl1961 (talk) 17:42, 18 August 2009 (UTC)

cover up all except left bank . exhaust is before inlet as in the other banks .the display is correct. ref: Andy Dingley talk.Wdl1961 (talk) 18:16, 16 November 2009 (UTC)

The image is wrong, but not so badly wrong that I think we're better without it, or that we should hide one bank (which we can't anyway). One bank is shown reversed. All crankshafts should have one inlet and one exhaust piston. Andy Dingley (talk) 19:16, 16 November 2009 (UTC)

the only requirement is that the timing on the inlet and outlet ports is correct . the combustion process does not care about ccw or cw rotation or that two rods connect to one journal.Wdl1961 (talk) 20:42, 16 November 2009 (UTC)

Say what you wish the images IS wrong in an article about a napier deltic, what may be true in general about a class of engines does not matter in an article about a specific type..Shortfatlad (talk) 22:42, 16 November 2009 (UTC)

ie compare this image showing exit ports http://www.thedps.co.uk/gallery/babydeltic/DSC_8632 - not the same as in the diagram.Shortfatlad (talk) 22:46, 16 November 2009 (UTC)

rotate 120 degrees ccw . In diagrams and math is not unique. chk rotation , reflection and mirror images. notice two same type ports are the same relative position in the engine picture as in the article . Pls do not change it again unless you have some logical proof.Wdl1961 (talk) 01:50, 17 November 2009 (UTC)

NO. in the image exit ports have threefold rotational symmetry overal. In the animated diagram they don't. Your reasoning is correct, but your conclusions are not. Please stop reverting. Thanks.Shortfatlad (talk) 16:35, 17 November 2009 (UTC)

It's just wrong. Each crankpin should have one inlet and one exhaust piston. Andy Dingley (talk) 09:08, 17 November 2009 (UTC)

take a careful look at the engine picture .two intake and one exhaust port . Wdl1961 (talk) 12:17, 17 November 2009 (UTC)

No, three inlet ports and three exhaust ports - one of each per bank. The obvious ports (red Hermetite sealant in the photo) are the inlet ports. These are fairly obvious on a Deltic, as they're on both sides of the bank (they look obviously "wider" as the manifold is cast internal to the block). Exhaust ports are just on the outside of the bank. They're also separate ports, as the exhaust manifold is a separate casting (not fitted in most of the DPS photos).

Also note that the animation diagram is drawn from the gearcase end of the engine, the opposite way round to the DPS photos. The reversed bank in the diagram is bank C. Andy Dingley (talk) 13:10, 17 November 2009 (UTC)

some more info in: www.wis.co.uk/justin/deltic-engine.html - At least they agree with each other. Wdl1961 (talk) 16:09, 17 November 2009 (UTC)

Diagrams

Here's some proper un-ambiguous info

• this image [1] via http://www.modelenginenews.org/etw/deltec.html
• also this image [2]

Both clearly show the location of the inlet and outlet ports (manifolds).87.102.78.86 (talk) 16:46, 17 November 2009 (UTC)

The same is confirmed at

• http://www.craftsmanshipmuseum.com/Tomlinson.htm
• http://www.histomobile.com/DVD_HISTOMOBILE/fr/tech/121-1.asp
• http://lh3.ggpht.com/_5q05hecr6uI/Sk5kVRXjVKI/AAAAAAAANow/Dr1EfE9uvK0/Napier_Deltic_-_001s_thumb%5B2%5D.jpg
• This link shows the same and also confirms that one cranshaft rotates in a opposite direction as already shown http://www.royalscotsgrey.com/deltics.htm (see phasing gear drawing).87.102.78.86 (talk) 16:51, 17 November 2009 (UTC)

Also http://www.ptfnasty.com/ptfdelticoperation.htm has excerpts from a book which looks fairly accessible, and includes info on firing sequence of the whole thing (ie a 6 bank 18 cylinder engine).87.102.78.86 (talk) 17:10, 17 November 2009 (UTC)

I can't figure it out either :-) I used to strip these things down at Ruston's at Vulcan Foundry, and it was definitely in-ex:in-ex:in-ex as you went around the delta, but I can watch the animation for hours and it still works with one bank's ports reversed... The phasing works, the scavenge works...everything. We used to dread these things coming in, along with when we had to fit new cast bedplates to all BR's Paxman Valentas. Fortunately we just stripped them and put the spares order together...they screwed them back together again somewhere else (Colchester I think :-). I think that the diagram is still good enough for explaining the general 'idea' of a Deltic, and I could not even approach the cleverness needed to create it, let alone correct it 86.148.252.237 (talk) 00:10, 7 September 2010 (UTC)

Sussed it! (I think). You have to watch for a long time, but it's the crank timing. If you leave the Top-Left crank as it is, then the Top-Right crank should only lead it by 20 deg. In fact its somewhere nearer 60 in front (because the animation has 12 frames). Same with the Top-Right and Bottom crank...the bottom crank also needs retarding so that it only leads the Top-Right crank by 20 deg. The combined effect of these two 'extra' leads is to put the bottom piston in the lead in the left cylinder, whereas it should lag behind the top piston. Once the Top-Right and Bottom cranks have been adjusted 'back' two and four frames respectively, the ports can be reversed in the left cylinder, and the scavenge will work the other way. Phew! 86.148.252.237 (talk) 13:22, 7 September 2010 (UTC)

Manual

http://pigeonsnest.co.uk/stuff/deltic/deltic.html

A possibly useful reference - reproduction of the original? multiple pages.Sf5xeplus (talk) 18:46, 6 February 2011 (UTC)

CT18-42K

There's a 3700hp version described here http://pcp.sagepub.com/content/183/2/35.full.pdf+html "DEVELOPMENT OF THE NAPIER DELTIC CHARGE COOLED ENGINE" by By R. P. Taylor and C. H. Davison

Doesn't appear to be in the article? 77.86.89.15 (talk) 03:42, 9 September 2012 (UTC)

Not clear what is happening here - a few days ago all 'old' articles on the site were available for access, and explicitly labelled as 'free', two days later that's stopped. ? 87.102.79.149 (talk) 15:37, 11 September 2012 (UTC)

Probably a mistake that it was free in the first place, and once they spotted the server logs, they fixed it.

Still citable as a source here.

Arguably it may even be freely redistributable onwards. If the publisher verifiably published it under a free licence (even by mistake), then that's an irrevocable licence. Andy Dingley (talk) 10:30, 12 September 2012 (UTC)

The SAGE articles can be viewed and downloaded for free until end Oct, email and username required, not much more. See http://en.wikipedia.org/w/index.php?title=Wikipedia_talk%3AWikiProject_UK_Railways&diff=517294195&oldid=515993081 for more details. (act now to avoid dissapointment..)83.100.183.189 (talk) 00:09, 12 October 2012 (UTC)

Blower/supercharger/turbocharger

My understanding is that these engines need an external air pump to work at all. If this is correct I think that such an explanation should be added to the article. This comment applies to the Culverin (http://en.wikipedia.org/wiki/Napier_Culverin) and Jumo 204 (http://en.wikipedia.org/wiki/Junkers_Jumo_204) articles too.

Indeed http://en.wikipedia.org/wiki/Two-stroke_cycle states: "Two-stroke diesels are all scavenged by forced induction."

Such a pump can in principle be a piston pump, a roots or centrifugal pump or any air pump. It could be mechanically driven or be exhaust turbo driven or indeed externally powered.

The Deltic appears to use a mechanically driven two-stage rotary compressor.

Note that this does not necessarily imply that the air pressure in the cylinders when the ports close is above atmospheric. That is, it does not have to be a supercharger.

Without such a pump there is no means for air to be drawn into the cylinders. In contrast a typical motorcycle two stroke uses the underside of the piston and the crankcase to operate as its air pump to drive the air into the cylinder. The Deltic does not appear to use that system.

http://pigeonsnest.co.uk/stuff/deltic/chapter1.pdf page 2, paragraph 2 -- states: "A geared-in type turbo blower unit consisting of a centrifugal compressor and a single stage axial-flow turbine... Port timing is so arranged that the blower completely scavenges and pressure-charges the cylinders."

Threebs (talk) 11:39, 9 August 2014 (UTC) — Preceding unsigned comment added by Threebs (talk • contribs) 11:37, 9 August 2014 (UTC)

It does actually mention it:

.. These engines are called "uniflow" designs, because the flow of gas into and out of the cylinder is one way, assisted by mild supercharging to improve cylinder exhaust scavenging. ..

I added more to the lead to make this explicit in the introduction.Prof.Haddock (talk) 21:55, 9 August 2014 (UTC)

If more info is needed on the type of supercharger a more informed source will be needed - I don't know if the same type of "blower" was used in all the engines of this type.Prof.Haddock (talk) 21:59, 9 August 2014 (UTC)

Though I don't have the citations that would be required to add anything useful to the article, from what I've been able to glean, all the production Deltics used various types of single-stage centrifugal compressor: the original 18 cyl (and also presumably the de-rated rail version) having a dual-inlet fan producing 7.8psi at maximum power, the 37K being a similar (if not the same) fan running at a 50% higher speed to give a 19psi charge, assisted by a turbine which produced nearly 60% of its 1,000bhp driving requirement at full power (though I imagine this percentage varied depending on speed), the remainder coming from a permanently-coupled drive from the engine; and the 42K, which featured a redesign including a single-sided compressor, but mostly changes to the engine coupling to avoid the problems the 37K tended to have with inertia and torsional stresses. It seems most of the 42K's power increase wasn't due to the design of the super-/turbocharger, which was mostly to aid reliability, but from the addition of intercooling.

And yeah, like I really 100% understand all of this, which is mostly just poorly regurgitated by someone who's fascinated but tends to go "huh?" when presented with the gnarly technical minutiae. :D --Vometia (talk) 08:19, 18 December 2018 (UTC)

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how are the cranks lubricated?

If anybody knows that would be good to add to the description. Gjxj (talk) 15:49, 26 March 2023 (UTC)