THE NAPIER DELTIC - HEART OF "THE MOST POWERFUL DIESEL IN THE WORLD"

[BEAUSABRE]

The story of Napier's 18 cylinder, 2-stroke opposed piston, triple banked Deltic engine - powering fast attack craft and what was then the most powerful diesel locomotive in the world (Imaginatively called "The Deltic"). Maybe FM was on to something...

(141) The Legendary Napier Deltic - 88 Litre Opposed 2-Stroke Triangle Engine - YouTube

Enjoy storyteller Curious Droid's tale!

[Overmod]

I still haven't quite figured out why the West Germans didn't adapt the 'inspiring' Jumo engines for use in fast passenger locomotives.  They would have been the perfect complement to what Ingalls would have built as their 2000hp passenger unit... but with higher lightweight horsepower.

Not as if they were averse to peddling technologically-advanced 4000hp locomotives with high-speed engines, or lightweight passenger-power drivetrains, to the potential American market...

[BEAUSABRE]

Overmod, I have vague memories that Fairbanks Morse was the US licensee for the Junkers patents. I am sure that if that was true, there was a clause in the licensing agreement that would have kept the German firm out of the US market. BINGO! Turns out that my memory wasn't so vague.

Fairbanks Morse Diamond Opposed-Piston Marine Engine | Old Machine Press

A bit about Napier's OP engines and the Deltic

Diesel Engines | Old Machine Press

Note that at the time a Deltic had 3400 hp, an EMD E9 had 2500 hp. Of course, the DD35, U50 and C855 soon arrived on the UP with 5000 hp, 5000 hp and 5500 hp, respectively. And Krauss Maffei had their ML-4000 4000 hp diesel-hydralics on the SP at about the same time. So it was a brief moment of glory, but it was still the most powerful passenger diesel by quite a margin.

[54light15]

My ship from when I was the navy from 1975-79, the USS Guam had two FM oppsed piston engines as emergency generators. We understood that they were recycled from scrapped WW2 submarines. 

[Shadow the Cats owner]

Just imagine being a mechanic on one of those things and it needed say a piston that was on the bottom crank replaced.  You pretty much have to tear the entire engine apart to get to that one failure.  This is why engineers need to remember the KISS principle big time.  BMW now has a V8 engine were the exhaust is in the valley of the engine and the intakes are on the outside of the heads.  Yet they can understand why this engine has valve guide problems from the oil failing as it is to freaking hot.  Oh yeah this engine is also twin turbocharged with the turbos sitting in the valley below the exhaust manifold pretty much in direct contact with the block.  

[BEAUSABRE]

54light15. The USN still uses FM OP engines - on nuclear attack boats built in the 1990's 

"These and other Fairbanks-Morse O. P. engines were also used as backup power on US nuclear submarines through the Seawolf class of the 1990s."

It would pretty wild if some of these engines had powered fleet boats of the Gato and Balao classes in World War Twice

[BaltACD]

BEAUSABRE

The story of Napier's 18 cylinder, 2-stroke opposed piston, triple banked Deltic engine - powering fast attack craft and what was then the most powerful diesel locomotive in the world (Imaginatively called "The Deltic"). Maybe FM was on to something...

(141) The Legendary Napier Deltic - 88 Litre Opposed 2-Stroke Triangle Engine - YouTube

Enjoy storyteller Curious Droid's tale!

So the 18 cylinder OP had 36 pistons?

[SD70Dude]

Shadow the Cats owner

Just imagine being a mechanic on one of those things and it needed say a piston that was on the bottom crank replaced.  You pretty much have to tear the entire engine apart to get to that one failure.  This is why engineers need to remember the KISS principle big time.  

I don't think British mechanical engineers ever heard of the KISS principle.  

British Rail would simply replace the engine if it needed work, and send the old one back to the Napier factory. 

[BEAUSABRE]

Shadow the Cats owner

Just imagine being a mechanic on one of those things and it needed say a piston that was on the bottom crank replaced.  You pretty much have to tear the entire engine apart to get to that one failure.

You just put your finger on a reason FM failed in the locomotive market. 

"Replacement of a single power assembly (cylinder liner and its two pistons) required moving the locomotive under a crane and removing (and later reinstalling) the locomotive's roof hatch, upper crankcase, upper caps, upper connecting rod caps, and upper crankshaft, making the operation much more time- and resource-intensive than a power assembly change on other engine types. Fairbanks-Morse learned that in shops that maintained multiple locomotive types, where the foreman was under pressure to repair as many locomotives as possible, repair of OP engines that required extensive disassembly was often delayed in favor of other types of locomotives that could be turned around more quickly"

The BR Deltic classes used derated engines to avoid the nightmare of tearing down the engines and there was a reason that if they developed problems, the FRU (Field Replacable Unit) was the entire engine, which was sent back to the shops to be be torn down and repaired there, before going back into the pool of spare rebuilt/repaired engines

"While the Deltic engine was successful in marine and rail use and very powerful for its size and weight, it was a highly strung unit, requiring careful maintenance. This led to a policy of unit replacement rather than repair in situ. Deltic engines were easily removed after breakdown, generally being sent back to the manufacturer for repair, although after initial contracts expired both the Royal Navy and British Railways set up their own workshops for overhauls"

[BEAUSABRE]

BaltACD

So the 18 cylinder OP had 36 pistons?

That's what an OP engine has, two pistons per cylinder. So. yes, 36 pistons

[54light15]

Beausabre- The Guam entered service in 1965 and the main engine, turbo generators and main air compressors were all recycled Big Two equipment. It would be nice to think that the FMs were from a sub like that but with it sitting at the bottom of the Atlantic after being sunk as a target in 1999, finding out would be a bit problematic. Tricky, anyway. 

[Overmod]

BaltACD

So the 18 cylinder OP had 36 pistons?

But no cylinder heads and no complicated valve gear.  A 9-cylinder FM engine would have 18 pistons.

The Deltic has '18 cylinders' but can be thought of as three FM-style engines arranged in a triangle with cranks in the three corners ... and then sharing cranks in the corners with appropriate timing changes.  So there are still 36 pistons in the engine, it is still only six cylinders long front-to-back, it only has three crankshafts, and at least in theory you could pull 12 liners (of 18) by removing only one crank if they come out in one piece like the FM's...

Another way to look at this is gluing three V12s together, across the decks of the blocks, but that doesn't capture the sense of most of the engine's design other than understanding how the first- and second-order balancing works.  Remember that one of those crankshafts revolves the opposite way from the other two...

One disadvantage is that the Deltic needs to have multiple rods sharing each crank throw, as a GM 567/645/710 does, rather than have one rod use the whole journal bearing surface as the GE 7FDL or GEVO does (the rod across the V of the engine bears on a similarly hefty-size journal in the connecting rod, similar to how radial engines do it).

[daveklepper]

Deltics powered British Rail's London - Scottland East-Coast expresses up to electrification.   Cab-ride nonstop London - Newcastle, steady 100mph, summer, 1976.   Catenary support poles already in place.

 

 

 

 

liverpol

[BaltACD]

https://www.youtube.com/watch?v=-vV-YaKsIGk

[charlie hebdo]

daveklepper

Deltics powered British Rail's London - Scottland East-Coast expresses up to electrification.   Cab-ride nonstop London - Newcastle, steady 100mph, summer, 1962.   Catenary support poles already in place.

 

 

 

 

liverpol

 

Not lucky enough to ride in the cab,  but rode behind one,  King's Cross to York, June 1968. Smooth.  Electrification came in the 70s as I recall. 

[daveklepper]

Correct  Not my 1962 visit.   1962 visit rode overnight in a sleeper.  Also, Aberdeen = Edinboro behind Gresley A4 Kingfisher.  First visit to the UK/Great Britain.

Must have been 1976 or about that time.   Still, a long  time ago.  Posting now corrected.

[charlie hebdo]

I certainly envy your ride behind an A4 in Scotland. 

[daveklepper]

Photos from thhe Deltic trip and THE diagram

 

 

 

 

 

[Overmod]

Old Machine Press page on the variants of the Deltic (including a detailed cross-section of THE diagram, albeit a static one):

https://oldmachinepress.com/2019/09/05/napier-deltic-opposed-piston-diesel-engine/

From BBC coverage on the history of diesel engines:

https://www.youtube.com/watch?v=wCA5pInfPpM&t=38m31s

Imagine what this would have to be for an engine with a valvetrain (note the idler that rotates the bottom crank the other way...)

https://i.redd.it/z91f93sazfx41.jpg

(To me the impressive thing about this is the number of studs securing the cover -- adds new horror to the old Murphy's Laws trope 'after the last of the wire-secured hold-down nuts has been torqued, it will be discovered that the gasket has been omitted...)

[Pneudyne]

Apparently the English Electric (EE) engineering staff were not unanimously in favour of applying the Deltic engine to traction applications, but the EE chairman supported it and so the prototype was built.  British Rail initially had no interest in acquiring the 3300 hp Deltic type as part of its Pilot Plan trial diesel fleet acquisition, but thought that it should try the engine anyway, so included the 10 members of the class 23, with the 1100 hp 9 cylinder Deltic engine.  Meanwhile though, BR Eastern Region management, having been denied electrification in the foreseeable future, saw the Deltic as an alternative way to offer a faster passenger service on the London-Edinburgh route, and so lobbied for a fleet of these.  It was acknowledged that the Deltic would be relatively expensive to run (with engine maintenance on a unit exchange basis), but it was calculated that with a small fleet, used only for fast passenger service, and with each unit running around 200 000 miles per year, the operation would be worthwhile.  Thus was a fleet of technically complex locomotives justified on a business case basis, rather than being the result of “technical push”.  The production version provided 3300 hp (gross) on 99 long tons (roundly 222 000 lb), with an axle loading of just 16.5 long tons (37 000 lb).  With axle-hung motors, this was acceptable for 100 mile/h running.  The HST power cars that replaced the Deltics had a 17.5 long ton (39 000 lb) axle loading with bogie-mounted motors, which combination was calculated to provide peak railhead forces at 125 mile/h that were no greater than those of the Deltic.

 

Although the Deltic was very complex, at the time – and for quite some time afterwards – short of electrification, it was the only available solution that provided the desired point-to-point speeds at track loadings within the limits that the civil engineers would accept.  Whilst its 3300 hp power output was logically its most prominently touted feature, the low total weight at which this was obtained was its key point.

 

 

Cheers,