The Napier Deltic is so iconic that you can simply say "Triangle engine" and everyone knows what you're talking about.

I was a young lad in England when and where 2-stroke diesels were moderately common. Commer trucks, and even a few buses, used the noisy TS3 (based on a Sulzer design) with just one crankshaft for its OP cylinders, Foden had their own 2-stroke inline-6 that sounded like a mini-me Detroit 6L71, and I've traveled many miles behind Class 55 Deltic locos hauling 100MPH trains on the East Coast Main Line out of Kings Cross, with my head out the window, flies and soot in my hair and face, relishing every moment of it! I never rode behind a Class 23 Baby Deltic loco, but they were even louder than their big brothers. The sound of a Deltic loco at full welly is, along with a Vulcan's howl, a sound that one will NEVER forget. To help keep those memories alive, I now have a bus with a Detroit 6V92 that I've straight-piped, and that also brings a big stupid grin to my face, especially when I use its Jakes.

My Dad was an apprentice engineer from Canada who got his post-university training at Napier. He started in I either 1950 or 51 at 21 ro 22 years of age, and quickly found himself on the deck of the torpedo boats with Deltics recording values and helping the engine room adjust to the machines. He also worked on the Deltic locomotives, and it's a double edged sword that he was picked by the company to spearhead the Montreal office's campaign to sell the Deltic in Canada. Napier was already in some trouble and didn't provide support to close the sales Dad tried to line up, according to my Mum, focusing on UK business instead. In the end, though, the Deltic experience led to him moving to United Aircraft where he ended up working to high-power fast naval projects, as well as the Turbo Train; and after that with Bombardier where he was back to diesels, and selling the LRC. Within the engineering community, experience with the development team at Napier was revered, and made a lot of doors open for him, for decades after. As a kid, we always had a sample actual cylinder from a Deltic in the basement, an ashtray made from a Deltic piston; and a beautiful scale salesmen'a model of the 18 cylinder Deltic; any one of which I'd give a lot to have now. He only had the highest praise for the engineering talent at Napier, and said that the draftsmen could teach you more than a senior lecturer at McGill, his aima mater. And just to address those here who are suggesting that the Deltic was over complex, it wasn't. The complexity was elsewhere, in the complex power train that tied the crankshafts together, distributed power to blowers and superchargers and pumps. But an 18 cylinder engine putting out the power of a 36 cylinder unit, but without any valve trains, no heads to leak, no cooling to perform at the head was in the end far simpler. And because all those eliminated units were ones that needed frequent adjustment for timing, involved camshaft wear, rocker friction , valve seat cracking, etc. etc.... nope, this was a masterpiece of simplicity.

The Deltics are such cool engines. I spent some time in the cab of 55019 and 55022 both featured in the video. That droning sound stays with you for the entire night after a day on the footplate. But they are thoroughbred race horses, with both engines running they picked up speed very well. Some of the locomotives even had names of race horses like Alycidon and Tulyar, others had names of regiments, those in the video 55019 Royal Highland Fusilier and 55022 Royal Scots Grey. The last one was pulling a freight in the video, but they were never built for this work, they were express passenger locomotives. The owner of 55022 had it mainline certified, usually doing rail excursions, but for a year he contracted the haulage of this freight running from Blythe to Fort William in Scotland, conveying alumina for aluminium production.

This channel has evolved into an appreciation of all things internal combustion and I am HERE FOR IT. 💙

My uncle used to be a fitter at BR Doncaster depot and spent a good deal of his career looking after the Deltic’s. Apparently they took a bit of looking after to keep them running well and they had a hell of an appetite for fuel but they were/are fantastic machines. Hearing one working hard is probably one of the best sounds you’ll ever hear!! I absolutely love the styling of the locomotives too, from an age where someone put some effort into making things look good!

American here who loves world locomotives. The deltic class 55 is one of the most amazing and unique machines of all time. It is the most incredible diesel electric, the Krauss Maffei diesel hydraulics of the Denver and Rio Grande were the most iconic diesel hydraulic, and the Fell Diesel Mechanical represent the best examples of their type in mt personal opinion.

The Commer Knocker was also an opposed piston two stroke diesel.

These engines were also installed in PT boats. I rode one in Vietnam.

Napier really didn't believe in the KISS concept 🙂 Incredible engine if you ever get the chance to hear one pulling hard.

Glad the Mack SuperPumper was mentioned! One more cool detail on that rig is that the truck used a Mack END 864 V8 (the predecessor to the E9). That thing must have sounded awesome!

Incredibly complex, but apparently, they have a good "time between overhaul ". Thanks for sharing 👍.

It is unreal the complexity but simple at the same time

Fascinating video, the sound of a Deltic Napier is as iconic as a Paxman Valenta and Rolls Royce Merlin

Great video Viso. The Napier Deltic was a magnificent bit of British eccentricity and magic.

The Napier Deltics were `also used in Norwegian designed Patrol Boats bought by the U.S. Navy in the 1960's.

Fantastic video. I've taken an interest in this engine before and thought I'd done a fair bit of reading on the subject. But you have uncovered plenty that I didn't know. Very interesting! An excellent video

I lived in North London in the 1970s, about 1/2 mile from the main line from London Kings Cross to Scotland. When I lay in bed late at night and it was otherwise quiet, I would hear the Deltics coming out of the tunnel at New Southgate absolutely flat out on their journey north. The noise was incredible and quite unlike anything I’ve heard before or since. Awesome!

Incredible engineering for even today's standards. .good old boys back then

I've watched many videos on the Deltic. This one is perhaps the best compiled, edited and presented short video on the subject. Nice job.

Excellent video. I had always held a grudge against the British Rail diesels replacing the charismatic steam trains, however, the ingenuity of the Deltic design has inspred a new respect for these locomotives.

You're doing amazing on your English and your videos! Keep it up

Brought back a few memories of building these during my apprenticeship at Paxmans where they were remanufactured. I even helped build the sectioned one in the video for the National Railway Museum. Good show. 👍

Dude your content is really impressive, video after video, it’s appreciated

I saw a lot of info and pictures that weren't in Flight Dojo's video! Thanks for the historical coverage on not only auto/cycle but also industrial/military engines/vehicle/equipment! Awesome content man!

An great engine with a really great sound.

In their final years of British Rail service one covered for a HST set. The crew let it rip and it kept HST timing by doing 121 mph (May have been faster) Considering they were only supposed to do the ton (100mph)

This is another very unique engine that I find very cool just like them old Detroit Diesels and EMD engines because not only it's a 2-stroke diesel, but it has an opposed piston design in a triangle that can make a decent lot of power.

The two clockwise/one counter clockwise rotating crankshaft was the key to getting the concept to work. Jumo built rhomboidal layout prototype engines during the War, but these had four clockwise rotating crankshafts and suffered from Human Centipede effect.

Good research, sir. Napier could think "out of the box"

Great video documentary, VR! Love the channel.

Despite how brain meltingly complex this design is. When it's built correctly and when it's maintained properly it runs as smooth as hell. No warm up time just crank over and vOoooooom

Fantastic sounding engines these! Great that you did a whole video on these, thanks VisioRacer 😎 Btw, 1 possible correction (if you're talking about the trains), the 18 cylinder engine cls 55 were retired in 1981, although a handful were sold, some of which ran (and some still run) special trains, and occasionally hired to haul freight, e.g in 2011 for 3 weeks, and for a single train in 2017 😎 I've got to see one of these in the flesh some day!

Napier have a long history of producing more powerful than everyone else's engines. Just take a look at the most powerful aero engine of WW2, the Napier Sabre.

Thanks mate, great video. I printed a simplified cross section image of this motor on a shirt for my pommy father in law. When he went back to England to visit family he got comments everywhere on the shirt.

Thx for an informative and well produced video. FWIW saw these in PTFs (.nastys) in Vietnam in '72 the gear cases were getting fragged by SVN operstors to keep from operating. Also saw in Coronado loved the sound of turbos with near continuous exhaust pulses.

Very good video thank you so much.

Excellent video. Thanks.👍

They liked screws and bolts at Napier. As always very interesting video.😊

Worked on them on the ECML at Gateshead MPD. Very informative video thank you.

Insane engines. Complex and yet somehow simpler. One of everyone's favorites.

Excellent job, great vid! : )

great video very interesting they sound fantastic and a brilliant bit of engineering 👍👍

great vid, what a cracking "lump" have a look at the intercity125 loco genset that was also stuck on leander/type40 ships as a container mounted power supply

Beautiful 2 stroke diesel engines. They are very interesting. I made a video in 3D about a week ago in my channel.

Thank you.

The sound of those Type 55's is the sound of my childhood until the 125's took over with their screaming engines.

4000+ HP *HIGH SPEED* diesel engine is no joke.I believe I saw a baby Deltic on a tug boat when I was young, because I could not "see" the crankcase / block / head intersection, (there is no head, lol) and it baffled me for a long time. Great content !

Fascinating video, thanks 🙏.

Just here to say i didn't watch you for a long time, now i see you have 500k subs bro, that's amazing to see, i remember Bravo hgt videos, i feel old now lol

Excellent overview.

Just when you thought that the 2 stroke Detroit was the dirtiest diesel out there. . . .

another great video .

Great content

Brilliant video

Fantastic video.

Great vid - thanks!

Again a brilliant video with rare images. The double piston concept is not able to meet emission regulations of today. The geometry of the combustion chambers are given by the shape of the pistons. Possibly one could improve them . . . . if there were somebody crazy enough. ;)

I can remember the Deltic diesel exhaust haze at Kings Cross station in London in the 1970s!. One other point regarding Napier that is interesting, the businessman and early racing driver S F Edge had Napier make his record-breaking cars for him. Their works was at York Road near Waterloo Station in London and built him the Napier Six. It is said the car was painted with leftover paint from painting the works- a shade of green that was subsequently named "British Racing Green."

You have a very cool and unique viewer base. Educational comments are the best ones

These engines were fitted to Ton Class MCMVs in the through until the 80's. Used to make lots of smoke, and often suffered from cracked cylinder liners forcing combustion gases into the coolant header tank. We had several starboard engines fail in a row. Got so good at swapping them out, we could exchange an engine in a weekend and back on patrol.

Railway engines (prime movers in North American railway terminology) have a vide range of application: locomotives, marine, stationary power generation, mining, etc. EMD, GE Transportation (now under a Wabtec ownership) are selling them for aforementioned use. EMD 567, 645 & 710 (their number indicates per cylinder displacement in cubic inches, all two-stroke) GE Evo engines. Even Alco 251 series are still being used to this day.

So many thanks VR for your dedicated research work!!.. 🏆 😊🙏

This is why I love this channel!

wonderful.....thank you so much

Good video, thanks.

Excellent video. Thank you. There is much more information here than I have previously read or heard. Another good reason for being a Patron🙂. Cheers from NZ.

A work of art

Beautiful engine what a piece of engineering and that sound .

During the late 80s and early 90s I lost count how many times I did the Kings Lynn to Liverpool Street route pre electrification and pulled by Deltic equipped locos!🙂🥰

The legendary Napier Deltic diesel masterpiece....once heard never forgotten.

*The **_Gegenkolbenmotor_** (opposed-piston engine) was invented by Wilhelm von Oechelhauser and junior partner Hugo Junkers, patented on July 8th, 1892.*

Wow,what a beast! Sounds like a hundred Commer lorries revving in unison!

In the class 55 the train heating boiler was located between the two Deltic engines. The noise experienced by a second man having at enter the engin room to attend the boiler while running must have been incredible.

Fairbanks-Morse (1) in the US who had purchased a license to build Junkers opposed diesels designed a 24 cylinder diamond layout 2 stroke diesel. It was under development for the US Navy during WWII but was abbandonded when the war ended. As usual see Old Machine Press. 1) F-M built diesels for diesel electric subs along with their own diesel locomotives.

87.9L supercharged diesel. That would lay down the power.

i worked at paxman diesels 70 to 83 assymbling these, very interesting

That last Boss evolution . . . 👌😳👍.What a beast ! Reminds me of the Russian Svezda that I think he already covered on a video.

Does anyone know where I can find more of the B&W footage from around 0:55s?? I have been hunting for that footage for years..!!!

Amazing 2t diesel

I always dreamed of scaling this down to a single cylinder, 2 pistons and cranks, about 1000 cc on a 5 speed box and put it in a motorbike. Somebody started that project 30 yrs ago but it 'disappeared' , suspiciously..

One thing Napier never shied away from was complexity.

These also have been used in ships for the military . The junkers jumo was of the same concept with just 2 cranks and opposed pistons for aircraft and was successful .

You should include the engine torque ratings again like you used too if possible, great video btw

that noise ! the deltic roar

I grew up with the sound of those diesel-electric trains. I love that sound.

I see you used some of my footage from my sister channel 'freightlocos' the animation you showed is wrong, one of the cylinder banks has wrong layout of exhaust and intake. It's my favourite loco and engine

If you get the chance visit York (UK) rail museum .., as I remember there is both a train & an engine on display ...

Miss the sounds and smells of the old engines on trains

The Bedford TM artic tractor had a two stroke GM diesel engine decades ago.

Sounds like a couple of 8V92 Detroits working in unison.

Maybe you could do a vid on Steve Morris engines. He mills his engines/heads from a billet of aluminum. He has several lines of engines that he sells. He also races them himself.

Awesome buddy 😎🤠🤠 too good..... greetings from India 🤘🤘 3:21 🎉🎉

The Jumo 223 that was the immediate progenitor of the Deltic. The 223 was a prototype diesel cycle, 24 cylinder, 2 stroke, opposed piston aircraft engine. Diesel technology made leaps and bounds during WW2- primarily in Germany. Although the UK and USSR as well could see that piston powered aircraft engines were the way of the future- jet engines notwithstanding. Diesel engines are more efficient, use less fuel and the fuel itself is far less flammable. I'd guess Germany also wanted to use a fuel that was less refined that high octane aviation fuel.

It is important to mention that Junkers also tried similar engines, one with 4 sides, the Jumo 224

My brother and his mate both bus drivers seemed to have a thing about the Delicts they went to see the last one coming through our town , to me it's just a train .

@VisioRacer You should also check out the characterful Paxman/Valenta engine used on the famous HSTs. Hear them scream on a heavy pull!

Those 2 getting craned off a wagon are currently at The Anson Engine Museum in Poynton Gtr Manchester 👍

The Rootes TS3 was also remarkable

Amazing bit of engineering, but also a good indicator of how far we've come. You could run a modern diesel off the exhaust fumes of one of these engines. They must have used a colossal amount of fuel, half of it is leaving via the exhaust stacks 😳