It's pronounced NAPE`-ee - ur. My Dad was an engineer for them in the period right after the War. It's my understanding that Napier felt, as you said, like the red-headed stepsister when it came to defence contracts during the war, and after. They probably had the best team of design engineers of the lot, but their solutions were based on complexity. So it doesn't mean much to say you have the highest power to weight ration, or the highest specific power, when that translates to unreliability in the field. My father began his career at Napier as an apprentice, right after University (BEng) in Canada, so he was a) well trained in engineering ideas and b) still required to take a highly practical path to the design floor. This might have been a post-war adaptation of work practice by Napier, in response to the disfavour that the Sabre met with, which was generally thought to stem from the unreliability of the unit. But Napier's roots were in old-school British engineering, and closely tied to the expectation of a practical engineer, not a lofty theoretician, as their ideal designer, so I doubt it. I think the premise of the video, "Ultimate" award, isn't well suited to the topic. Without a doubt, a better trained ground engineering staff, able to work effectively on the Sabre would have improved things; so would better maintenance schedules; so would better logistics, for the delivery of spares. But in each of those caveats, there's the reality of war: the Ultimate engine most certainly isn't the best engine, if it fails on all those criteria, which the Sabre did. More importantly, it did worse than the other engines around it, like the Merlin, of course, but also the many Pratt and Whitney radials, whose design philosophy was built around simplicity, repetition of parts, simplicity of machining individual parts, and potential for improvised field repair. These were not ideas that the engineering elite in Napier gave much thought to. A rather tragic side note to this: my father was in his late teens on D-Day, and finishing high school. On that day, the person in our family he looked up to, far beyond anyone else, his uncle Mel, was lost, in a Tempest (might have been a Typhoon), and the wreck and his body was never recovered. Given that, it's generally felt that the most likely scenario was that after getting detached from his group, he made his way back over the Channel, and a lilkely cause of death would have been the failure of the engine in his plane. The death affected my father hugely, and he never stopped referring to Mel, decades afterwards. And after graduating, he went well out of his way to secure that apprenticeship with Napier; that's how he ended up in the UK, how he met my mother, and that led to the guy writing long comments on KZread, 65 years later. But I wonder, and have always wondered, if joining the firm was in some way connected with making things right that had gone wrong for his hero....

@flightdojo

2 жыл бұрын

I agree that I'm using the term "ultimate" a bit loosely here and only applying it to power output rather than the numerous other factors, as you mentioned. I think the next video will cover the R-2800, which many would agree -- alongside the Merliln, which deserves its own video -- was the real work horse of the war. Also, what an incredible story! While tragic, it's so interesting the personal connections people form to these bits of history.

@lewistaylor1965

2 жыл бұрын

I've been pronouncing it correctly...Thanks for the story about your father...You know, I use to fly a Battle of Britain flight sim called 'IL2 Cliffs of Dover' (checkout the dogfights on KZread)...and there was an airstrip at 'Lympne' during the Battle of Britain that you could use in the sim...We used headphones as comms so we could fly with folk worldwide all in real time (still amazes me)...Anyhoo, nearly everyone had a different pronunciation for 'Lympne'...so I phoned a pub in the Lympne village and asked them just to put the debate to bed...It's pronounced 'Lim'...The bar staff laughed at the call...

@MrBeboopman

2 жыл бұрын

Thank you for sharing that fascinating story..

@seanm8030

2 жыл бұрын

Good engineering solutions meet the specification using the least cost and complexity. In the case of the Sabre, Napier proved that they could meet the specifications, but at a cost and complexity that meant their solutions were not, at least initially, mass produceable. In the normal market this sort of solution can be acceptable provided you can secure funding to continue development... again and again. In wartime it can be fatal.

@johnmclean6498

2 жыл бұрын

@@lewistaylor1965 Only the English could come up with Lympne and pronounce it Lim. Wonderful. I fly DCS simulator (from Spitfire to Hornet) and yes - it amazes me that I can fly online with international friends on missions. Just got the Winwing HOTAS controllers.

It’s unfortunate the Bristol Centaurus the radial sleeve valve wasn’t used in WWII earlier as well as the Sabre. Napier was an amazing engineering firm, their Deltic 2 stroke triangle diesel was amazing.

@number1genoa

Жыл бұрын

I love the Sabre for it outrageous design however I read somewhere that the thickness of the Sabre sleeve was limited to around 0.1 inches to allow for adequate heat transfer but at this thickness it was prone to distorting under high boost such as would (presumably) be required at high altitude. This distortion squeezed the oil between the sleeve and the liner with predictable consequences, and also lead to "Clipping" as the sleeve flexed while transiting the ports. to quote wikipedia "Without the advanced supercharger, the engine's performance over 20,000 ft (6,100 m) fell off rapidly and pilots flying Sabre-powered aircraft, were generally instructed to enter combat only below this altitude" I'm assuming this Achilles Heel also applies to the Bristol Centaurus and Hercules engines. Ultimately the poppet valve engines were superior in this regard. Indeed the 130/131 series Merlin produced 2,070 hp a staggering achievement for a 27 litre engine , the book by Calum Douglas is an excellent resource www.google.com/search?q=the+secret+horsepower+race&oq=the+secret+horsepower+race+&aqs=chrome..69i57.11537j0j7&sourceid=chrome&ie=UTF-8

@skippmclovan1135

Жыл бұрын

Twin Bristol Hercules radial sleeve valve engines powered the Bristol Freighter aircraft. I recall take-off power rpm was 2,200, and cruise continuous rpm was 1,800. They were 'slim' for radials, and very smooth and quiet comparatively. Start-up did require a full cockpit verbal 'Fire Drill' procedure each time and a long nozzle fire extinguisher and an external attendant adjacent to each engine. The Wright Cyclone and P&W radials were started with less drama. They were generally noisier and more vibrational however, unless absolutely zero-timed straight out of a full rebuild.

No words are enough to show my appreciation and thankfulness to you for not using any music in the video. KZreadrs always have a knack for choosing the most irritating background music. Your voice is beautiful and relaxing! Thank you!!!

There's a reason poppet valves are still the most common type of piston engine valve and sleeve valves are pretty much unused today. That reason is the levels of maintenance required to keep them operating efficiently and the incredibly high cost of constant replacement of sleeves. Sleeves wear out quickly whereas poppets will generally last far longer with far less maintenance required. In theory sleeves are awesome in that they provide far better flow. In practice, they are temperamental and wear out very, very quickly. Once you loose the seal between the sleeves, they foul with a mixture of intake and exhaust gasses and begin to stick, which requires a complete tear down and rebuild to replace the sleeves. Even if a poppet valve sticks, you only need to remove the head to repair it.

@jamesrindley6215

2 жыл бұрын

There's also the complexity of the gears required to drive the sleeves vs the relatively simple cam needed for poppet valves.

@seagriffon1016

2 жыл бұрын

And there was me thinking the Bristol Hercules and Centaurus engines had a much higher TBO than all other aero piston engines in their hey day (?) [Civil Centaurus max TBO was 3000 hrs but this was dependent on using AeroShell 100U an oil specifically developed for SV engines].

@jkemmery

2 жыл бұрын

@@seagriffon1016 Interesting. Do you have a source for that? I was not able to find any info on TBO for any WW2 engines besides Merlins and R-2800s. If I'm not mistaken, the Bristol engines used a single sleeve with both the intake and exhaust ports in the same sleeve, whereas the Napier design used 2 separate sleeves for intake and exhaust.

@TheStrathmoreChannel

2 жыл бұрын

@@jkemmery The Sabre has 1 sleeve shown at 6.22

@jkemmery

2 жыл бұрын

@@TheStrathmoreChannel I was mistaken, my bad.

So incredible how much engineering went into these piston aircraft engines and how they were 50 years ahead of automotive engines. Crazy precision engineering, thousands of moving parts machined perfectly just to be beat out by a spinning shaft in a tube with fans on the end of it.

@phildavenport4150

2 жыл бұрын

Exactly. Not so "Ultimate" was it?

@ThePaulv12

2 жыл бұрын

A couple of things, every mechanical principal was worked out by 1929 and jet engines were helped by a good understanding of the steam turbine. Multistage superheated steam turbines with stator sections producing tens of thousands of HP were around for nearly 50 years before the jet went mainstream. That thorough understanding of gas flow, thermodynamically speaking helped jet design. Jets really are not as flexible in operation as you might think. The topic of jets gets complicated fast. For example, the holy grail of jet design is efficient low altitude jet engines. To that end we're not even close to solving that one. Basically jets are really only useful at altitude and in military service where ridiculously high fuel consumption at low altitude is less important than defense. Jets are pretty hopeless for hot and high takeoffs like 5000' elevation and say 35deg C which is why there's the turboprop engine. What I've just written is about .000000000000001% of the complexity the jet engine strengths and limitations. Those limitations are profound. Piston engines by comparison are very flexible, particularly with a turbocharger. Jets come into their own over 25,000ft but even then they still lose thrust as the air thins, albeit less than all other engines. It's complex.

@griesTheGries

2 жыл бұрын

the safest, most reliable , very high power to weight ratios.....along with way lower maintenance requirement is why turbines are dominant...piston pounders dont come close.....

@casematecardinal

2 жыл бұрын

@@griesTheGries the only problem is that they are extremely fragile.

@GGigabiteM

Жыл бұрын

​@@griesTheGries Jet engine safe and require less maintenance? I want whatever you're smoking, that must be some good shit. Piston engines can have holes blown in the block and cylinders shot off and keep running. A jet engine can be completely destroyed by a stray bolt on the runway, or a bird in the wrong place. Piston engines also use orders of magnitude less fuel. Piston engines win in every category except weight and speed, but the speed part is less of their fault and more of a problem with propeller physics.

The beauty of the Napier Sabre was that it combined the massive power of a radial engine while also having the small frontal area of an inline engine. The only reason the typhoon and tempests weren’t even faster was because of the huge chin radiator. The fullest potential of the Sabre was realized when hawker made the Fury I, a land based variant of the sea fury with a 3500 horsepower Sabre VII. It combined the same ludicrous power as a 72 liter wasp major, with an airframe as sleek as a mustangs. It could do 490+ mph at just 14,000ft. Not even the hornet, super Corsair, or p51h could match its performance there. In fact no other prop fighter could.

@Splomf

2 ай бұрын

The hawker fury? I can only find reference to a biplane when looking it up. Do you mean the sea fury? I can find that, but it's radial

Greg's Airplanes and Automobiles has done some excellent looks at how much induction systems matter. For example, the huge increase in performance when the P51 Mustang was changed from using the Allison to the Merlin, the induction system mattered far more than the engine itself. Multiple stages and multiple speeds of supercharging was the real gain there.

@davidelliott5843

2 жыл бұрын

Te Rolls-Royce supercharger became so well developed for flow and efficiency that it was used in early turbojets. It was that good.

@michaeld5888

2 жыл бұрын

A good read is 'Not Much of an Engineer' by Stanley Hooker who was instrumental in sorting out the supercharging of the Merlin. They put him in an office without a specific remit and he wandered around the site and walked in to the supercharging unit. He was a prime mover with the Bristol Olympus and he was even hauled out of retirement to sort out the problems with the triple spool RB211. A major player in UK aviation up there with Mitchell and Camm.

@singleproppilot

2 жыл бұрын

The important point is that the superchargers of early aviation engines were always integrated in to the crankcase, so changing the design of the supercharger meant redesigning the whole engine. For whatever reason, there was no such thing as an external supercharger back then. This meant the design of the supercharger was fixed very early in the development process, and it was critical to the performance of the engine as a whole. The American made Allison V-1710 used a single stage, single speed supercharger which reached its critical altitude (the highest altitude that the engine can still make full rated power) in the 12-14 thousand feet area. But when Rolls Royce designed the Merlin, they had the remarkable engineering foresight to build a two stage, two speed supercharger in to the case which could achieve far higher pressure ratios than than a single stage, single speed unit. P-51s with the Merlin engine could make full power in the mid 20-thousand foot range, with still plenty of power available even higher. Higher altitude comes with lower air density which means less drag, but with the engine still making nearly full power you could go faster and go farther on the same fuel load, which is why the P-51 could escort the bombers all the way to Berlin and back.

@DC.409

2 жыл бұрын

@@singleproppilot The two stage Merlin 60, was designed for the high altitude Wellington, Stanley Hookers objective was 1000hp at 30,000 feet which he achieved, the story then goes Hives asked for it to be fitted into the Spitfire V becomes the Spitfire IX, the irony is the Spitfire VIII is the new enhanced design arrived after the IX and was superior in performance. A key reason for this success was Vulture, it’s large supercharger was used has the basic unit and married to the existing Merlin supercharger on a test bed, from that they developed the Merlin 60 series. Undoubtedly the best Merlin was the Merlin 100. A geared Vulture test bed was also used to test the balance of the turbine for the Derwent

@raywhitehead730

2 жыл бұрын

Gregg is boss.

Very nice video on the Napier Sabre engine and its development. Typhoon Legacy Company, Ltd. in Canada has a Napier Sabre engine that they intend to restore back to airworthy condition for their Hawker Typhoon restoration project. Hopefully it won't be too long before we get to hear a Sabre engine roar to life again.

Not surprising to see an interesting and clever configuration from the company that produced the Deltic motors.

@francovance1

2 жыл бұрын

The Deltic is said to be based on the Junkers Jumo design.

@fooo2241

2 жыл бұрын

@@francovance1 thats interesting! It didn't make sense to me, so I looked it up. I was aware that Junkers had made the inverted V-12 designs, but I was unaware of them producing an opposed cylinder motor. Wikipedia has a pic of a Jumo 205 cut open to reveal the pistons, what an unusual looking design!!

Wow! Wonderfully produced and highly informative video. Thank you so much for your hard work!

The genius of the designers and engineers of that time designing and machining such a complex engine without CAD or CAM is staggering.

I really think it’s cool how you can do so much research and shed light on the different engines of the past and help all of us understand the technology they had back then to make that kind of power considering the engines large size and displacement I just think it’s neat and what’s even crazier is is the sleeve valves on the engine that is quite interesting To think back in those days they were able to do that and make it work

Amazing the blocks and components could handle the stress at those power levels. Really amazing engineering and skilled tuning for the time.

@default123default2

2 жыл бұрын

I wonder what else has sleeve valves. Seems like a good idea

Thank you so much for this educational video. I've always had a fascination for this engine, and also the Tempest, but honestly I know very little about mechanics. This video has really helped me understand some basics about ww2 aero engines, and helped clear up & understand unknowns, for example reliability. I believe you right, that the napier sabre truely is remarkable engine. Btw, is it possible you can put a link to part2 within the description? Many thanks!

Thank you so much for this wonderful outlining of this fabulous engine, so very well researched and illustrated here and I look forward to part 2 very much.

Very interesting, but of course all that power ends up going to waste in a) throttling losses with all these massive 'victorian' engines, and b) propellers are very inefficient without some form of tube to direct the airflow backwards. Frank whittle was getting 800lbs of thrust before the war in a dirty old shed with no money and no help with metallurgy. The best book on this subject is 'Not Much of an Engineer' by Stanley Hooker. A brilliant read. From knowing nothing about engines to designing the engines in the Harrier VTOL and Concorde is an astounding achievement. .

Interesting and informative. Can I point out that the engine layout was an 'H' 24, made up of 2 flat 12 engines, stacked, with the crankshafts geared together, not "2 'H' engines, as you referred to it.

Thanks for this impressive presentation. I once read that later with lots of methyl ethyl lead and boron, two hundred octane fuel, it danced around five thousand hp but was put away in favour of Jet development. The RR Cressi interests me. The full mass of everything associated with the normal operation of an engine through expected missions is it's weight.

@bluspectre2042

Жыл бұрын

With that much fuel additives, that couldn't be a viable production engine. Fueling that would be far to expensive! Still would be impressive.

Nice delivery of information, amazing to think that even then big companies doing their stuff to make sure they are top. Nothing has changed. You can now do the Napier Deltic which is also insane.

i worked on pratt & whitney r3350-32 & 34wa engines in the 60's at alameda ,ca. that engine produced 1 hp per cubic inch 3350 hp, the engine had an engine driven supercharger with a huge carburator, along with power recovery turbines utilizing exhaust pressure to spin 3 turbines that were hooked in to the crankshaft via fluid couplings, as well as water/alcohol injection to offset detonation. the engine was used in the A1E skyraider for the navy and the airforce, as well as the constellation cargo/passenger for the navy and air force

impressive amount of moving parts! i've never heard of a sleeve valve or this engine, the youtube platform really opens up a wealth of knowledge, thanks to all involved.

A complete understanding of this engine needs to include the story of the difficulties Napier had with sleeve valves and the assistance Napier got from Bristol. Also, to understand the problems the engine had to overcome one needs to understand the air frames this engine was mated too.

@wbertie2604

2 жыл бұрын

To some extent Bristol had to take staff off the also problematic, sleeve-valve Centaurus to help with the Sabre. So ironically the Tempest V with the Sabre made WW2 and the Centaurus-powered Tempest II did not.

@flightdojo

2 жыл бұрын

Hey Lorrin, check out Part 2 for that story!

@ThomasDoubting5

Жыл бұрын

To my knowledge the sleeve valve issue was completely rectified by the Tempest

I had no idea the Napier Sabre existed. I only knew of the Allison, Pratt &Whitney, and the Rolls-Royce. Great video.

When I was going through A&P (Airframe and Powerplant) school we had one on a test stand and would run it during the Powerplant portion of school or the last 8 months. This is a very interesting engine to say the least

@RamblerMan68

2 жыл бұрын

How cool was that to see run?! Where did you go to A&P school? Thanks for sharing👍😎

@uncletoodles8118

2 жыл бұрын

My dad said they used a bunch of different old 1930s and onward engines at a&p school here In Chicago in the 1990s. He said that he had a portion of the schooling taught by a former Tuskegee Airman named Cornelius Coffee

@HerrmannThompson

Жыл бұрын

When were you and A&P School? As far as I know there aren't any running Sabres today.

Very impressive engineering design. I'd love to hear one run in person!

stumbled on to this bit of history. shows how little engines have actually changed compared to an old technological marvel! thx for sharing!

@arkhsm

2 жыл бұрын

Did you see the rod design ?!

@kevinim300

2 жыл бұрын

@@arkhsm which part?

@arkhsm

2 жыл бұрын

@@kevinim300 Look closely at 4.27 into the video !!

Very interesting video regarding the very powerful Napier Sabre engine. I didn't realise how hard the Rolls-Royce was lobbying so fiercely against this marvellous engine and ultimately almost destroying it's reputation by continuous lies such as reliability. Fact is that this engine with its "H" configuration was very complicated but frankly speaking also the Rolls-Royce Merlin was no joke as both engines required highly skilled mechanics to work on. I find this video very interesting and informative. Really a good job and looking forward to see the 2nd part 👍👍👍

Really enjoy the engine vide,thanks so much for creating them!

The Bristol Centaurus would make an interesting comparison with the Napier Sabre. Both sleeve valve, both 3500 hp, one air-cooled, one liquid-cooled. The Centaurus was used extensively post WW2, and the Sabre was not.

@johnmclean6498

2 жыл бұрын

Good point. Surprised it wasn't considered.

@tempestmkiv

2 жыл бұрын

It's my understanding that even though the Centaurus was designed in the 30's it didn't go into production until 1942 due the Bristol concentrating on Hercules production which was in several types of aircraft at the time. The Centaurus wasn't really needed since the Napier Sabre had been in production since 1939 and filled the bigger horsepower niche along with the RR Griffon which was first put into an airframe in 1939.

@leneanderthalien

2 жыл бұрын

@@johnmclean6498 the explanation is that the Napier Sabre was relatively unreliable and the Bristol Centaurus far better...The Bristol Hercules (14 cyl, but same design) was built up to 1964 under license by SNECMA for the Nord 2501 Noratlas, a french military transport aircraft who was operational use up to 1986

@wbertie2604

2 жыл бұрын

@@tempestmkiv Hercules was in use for current production with room to improve performance, in particular improved supercharging. Sleeve-valve was an issue for Bristol. Helping with the Sabre may well have also diverted effort. I am not sure you could really say the Sabre was in production from 1939 - more some pre-production. It was favoured for many things in the 1939-40 in the UK based on RAF specifications. The Centaurus was seen as something more appropriate, potentially, for naval or hot climate use of the same class as the Sabre. Plus Bristol liked to use its own engines.

@tempestmkiv

2 жыл бұрын

@@wbertie2604 Just checked some sources. The Napier Sabre was conceived in 1935, prototype completed in 1937, testing in 1938 and passed the 100 hour test requirment for the RAF in June of 1940. Production of the Sabre II started right after that so you are correct, not 1939. Thank you.

Very cool, superbly explained and enlightening. Well earned Sub! Look forward to more content. Greetings from Gulag Ontario, Canada

@jacktattis

2 ай бұрын

Gulag?

Great numbers. I can't get enough technical info most of the time. Your a flood of tech on this engine. Thanks

A very educational video,I am looking forward to part 2.cheers Roly 🇬🇧.

Very interesting piece you've presented here. I had to smile when you backed off of comparing any of these engines to the Allison performance after the war. Post war and through the late 1970's, you could just about buy an Allison engine for the same amount that a new small block chevy would cost. That being said, the Allison engine found itself in all sorts of applications the war planners could have never envisioned. Specifically, unlimited hydro boat racing and tractor pulling. I was once told by EJ Potter of drag racing and tractor pulling fame, that the Allison was, for awhile, the perfect tractor pulling engine. It turned out in stock form, 1700 hp at 1700 rpm. If you needed 4000 hp, you just spun the engine 4000 rpm. Of course, the risk of falling out of the sky if you dynamited an engine doesn't apply to tractor pulling (thought it does thrill the crowd). I suspect that for the Allison, a margin of safety in flight kept its actual horsepower output in check during the war. That may also be true of some of these other engines. That all said, look how much farther we are in the search for horse power in a per cubic inch basis and also on a per pound basis. Almost every car offered in 2022 delivers more than one horsepower per cubic inch, many are above two hp per cu in. And the weights of modern engines are now in the less than 300 lbs area for the same specific out put engines weight 2.5 times that much would deliver just 20 years ago. Don't even get started comparing motor cycle engines for out put.

@alan-sk7ky

2 жыл бұрын

Yep, bikes busted through the 100 bhp per litre grail in production engines in the early 80s 😉

@BuzzLOLOL

2 жыл бұрын

@@alan-sk7ky - In 1960's, the Suzuki 50cc bikes were making about 6.5 HP and 55 MPH... 1966 Suzuki X6 Hustler 250cc 29 HP and 104 MPH was beginning killing off the British motorcycle industry... 1971 Kawasaki triple 750cc 74 HP and fastest production motorcycle in the world...

I remember reading a paper on sleeve engines at some point and it uses the Sabre a lot as an example. It seems, at least in part, that the sleeve engine design had a lot to do with the excess weight and happens to be a trend across many sleeve engines when compared to many valve engines. On that note I also think it worthwhile to remember that a sleeve valve also requires a great deal of very precise machining and so the design might not be quite as preferable to the air ministry. I'm sure corruption also played a role, but there certainly were other factors.

@brucerogermorgan2388

2 жыл бұрын

Please note that the terms are sleeve-valve and Poppet valve, not just sleeve and valve.

@olivialambert4124

2 жыл бұрын

@@brucerogermorgan2388 I mean yes. But also people informally tend to use sleeve and valve, and I figured the more common verbiage was easier in what is frankly an informal comment.

@brucerogermorgan2388

2 жыл бұрын

@@olivialambert4124 No, people do not informally use sleeve and valve. It's always sleeve-valve, or poppet valve, or overhead valve, or side valve, or similar. Sleeve-valves are valves too, but sleeves are not, the term applies to steel cylinder sleeves, often used in aluminium cylinders.

@olivialambert4124

2 жыл бұрын

@@brucerogermorgan2388 Perhaps not to you, but its a consistent feature where I've looked. Both casual with outsiders and industry professionals. So with that said I'm going to go with sleeve engine and valve engine. Especially on a youtube comment.

@olivialambert4124

2 жыл бұрын

@@brucerogermorgan2388 Also for what its worth, overhead valve often informally refers to specifically a pushrod engine rather than all forms of overhead valve. Probably not the best term you could have suggested there. And poppet valves can refer to L head T head and F head engines whilst overhead valve is primarily used to distinguish from them (rather than sleeve engines). Again, not the greatest suggestion given L head were still fairly common in that era.

Fascinating i only knew Napier for the Deltic locomotive engine and that is a monster.

This was great, thank you. If you happen to do any more of these in the future, it would also be nice to see the specific fuel consumption numbers just to round out the final metrics. If the fuel requirements are double another engine, any power-to-weight advantage will naturally be nullified by having to carry twice as much fuel, etc.

Great presentation mate. Learned a lot and thank you. Complex design can achieve amazing efficiencies and performance BUT it can also lead to logistical and maintenance headaches during wartime conditions. The fact that the Tiffies performed so well during the Normandy campaign speaks volumes about the planning, training and logistical support that had been mapped out over the years before the invasion. It would be fascinating to see how reliability rates compare during the first 2 months of the liberation campaign as opposed to the next 2 months. Does anyone out there have this data? 🤔

i had known about some RR sabotage with the engineering side against the Sabre, but i never knew that it went that deep!

@jacktattis

2 ай бұрын

Oh yes Rolls Royce were bastards

You are an excellent narator ... not quick or in a rush, your voice is (For an American) soothing and you are clear and concise ... Well Done You :)

Im glade to see you trying something new with this small series, keep it up and you'll be heading off to random KZread creator events all over the country!

Perhaps you should add to your reading list Sir Stanley Hooker's autobiography 'Not Much of an Engineer' which gives a much greater insight to the problems associated with engine development prior to and during ww2. Though I don't doubt that RR did interfere with the adoption of any competitive engine, the British faced a steep learning curve to become competitive with the enemy. Many of the breakthroughs were made by private ventures and elements of good luck which, eventually overcame the Air Ministry's stubborn refusal to accept new ideas. The RR Merlin was one as was the Spitfire, Mosquito, etc. As I see it, British industry was not well prepared for large scale production and the rush to remedy that was chaotic. For example RR used fitters to assemble their engines and were all by definition hand built. Ultimately, all the drawings and tolerances had to be changed to allow contracts to other engineering companies to mass manufacture the RR Merlin. For example, Packard. The choice of putting what few eggs it had in one basket, meant that getting a universal power plant to give good performance across a number of different airfares with differing performance requirements was very obvious. RR to their credit tested their engines to destruction to eliminate any weaknesses throughout the conflict. The RR Merlin was the smallest displacement aero engine of any front line aero engine for the duration of the war. At 27 litres it started life at slightly less than 1000hp and ended producing 2000hp and in special cases 2500hp from the same displacement at the wars end. The Merlin was regarded as very reliable in service possessing the ability to accept additional boost in emergencies. However the Ministry's resistance also limited the use of Bristol's sleeve valve radials in British airframes despite having higher power ratings and simpler air cooled designs. It is difficult to imagine the Napier engine being as flexible beast to attain volume production and be useful for such a range of airframes. Also, we are talking about different time periods the RR Merlin being a pre ww2 engine versus an engine produced later during the war. By the end of the war it was increasingly obvious that piston engines were reaching their limits as required power needed for a given performance boost was becoming exponential. The jet engine was proving to be the next step forward. My apologies for straying off topic.

@dukecraig2402

2 жыл бұрын

The changes made for the engine to be mass produced had to be done for Ford of England not Packard. The changes made for Packard to produce the engine were made to the blueprints, American Industry used a different viewing plane on blueprints than British Industry did, by the time Packard was brought into the loop the tolerance changes required for mass production had already been done as per the requirements for Ford of England.

@christurner6430

Жыл бұрын

@@dukecraig2402 I was told years ago that it was Ford who built the reliable Merlin engines whereas the 'original' RR-built ones routinely dumped their engine oil en masse over the pilot's windscreen.

@jacktattis

2 ай бұрын

I read somewhere tha t when Rolls Royce tried to get them to stop the Sabre Lord Beaverbrook in laymans terms said" shut up and go and build your own and stop interfering"

@jacktattis

2 ай бұрын

@@dukecraig2402 No Rolls Royce approached Ford first and after dithering about Ford said no as he considered it unwise to build for Britain as he thought Britain was going to lose the war , As did Joseph Kennedy 2. Ford had copied the Diagrams and made an Engine later in the War and tried to sell it to the USAAF who said NO. Ford did build tank engines I believe 3.They are drawing conventions Britain /C/wealth use First Angel and the USA Third Angel We could do both the USA only Third Angel

@jacktattis

2 ай бұрын

@@christurner6430 Rubbish Ford England did not build them Its factory was taken over by Rolls Royce

Thanks for a great video on an all too frequently overlooked engine! It would be nice to see how the Napier Sabre compared to the Bristol Centaurus; it would also provide an unusual opportunity to see how an on-paper comparison is or isn't reflected in real-life service, as both were fitted to different variants of the same aircraft.

VRROOOOOMMMMMM love it. Kudos again. I'm on the prowl for a static scale model. Thanks for renewing my interest in this uniquely oddball engine

I'm always in awe of the people who draw those cutaway illustrations.

Excellent video! I can't help but wonder what the horsepower, the horse power to weight ratio and the bfsc (pounds of fuel per horsepower per hour) efficiency rating of this already incredible engine could have been if Napier could have also added either turbocharging or turbo-compounding along with port fuel injection to the Sabre. I'll bet the output in all three of these categories would have been absolutely astounding.

@georgesheffield1580

Жыл бұрын

And TBO ( time between overhaul)

Read the book "The Big Show" by Pierre Closterman. He finished the war in Tempests. Basically combat notes from his service. It is very visceral, awesome read.

@Gorbyrev

2 жыл бұрын

If I remember rightly he was chosen to chair a Spitfire vs Typhoon debate as he had flown both. It is quite a memoir.

@flightdojo

2 жыл бұрын

I've wanted to read that! Just ordered it on Amazon

@rodneypayne4827

2 жыл бұрын

Typhoon Pilot by Group Captain Desmond Scott (RNZAF) is a great read as well,if you can find it.

@brianmuhlingBUM

2 жыл бұрын

I really ead The Big Show when it first came out and fell in love with the Tempest and the Sabre power plant. Well worth a read.

@earlpetrikin9906

2 жыл бұрын

I purchased my copy many years ago and I must have read it 3 or 4 times.

I had never heard of this engine. Napier has made some very cool engines.

Incredibly or insanely complicated and efficient engine! Nothing comes close when comparing with today's combustion engines. Very good work! Thank you!

On the reliability issues, once they had sorted out the problems with the sleeve valves the Sabre became a more reliable engine than the Merlin contri to more often hear. Also checkout the Tyhoon RB396 restoration project, their aim is to bring a Hawker Tyhoon back to flying condition, they currently have a factory sealed Sabre waiting the funds to bring her to life for the first time since she left the factory.

@jimhenderson9167

2 жыл бұрын

There is also Typhoon JP843 being restored in Canada. Imagine being able to see two flying together again!

@andrewtadd4373

Жыл бұрын

@@jimhenderson9167 on a par with VERA and Thumper the only airworthy lancs currently in existence. Had the pleasure of seeing both flying at treetop level with the BBMF over Goodwood one sunny Saturday afternoon.

Good job, this was well laid out and I learnt some interesting history - can you believe this is a 1930’s engine! And the low handed stink RR made over it. The only thing that could have been better would be larger engine names below the bar graphs.. and more shows about interesting topics like this! Again, well done 👌🏼

I appreciate your efforts to bring the story of this engine out of the “memory hole” to which it has been consigned. Your methodical approach to analysis combined with a willingness to admit what you aren’t sure of enhances your credibility. It has always seemed odd to me that, of the thousands of Hawker Typhoons and Tempests powered by this engine that helped win WW2, the Royal Air Force hasn’t managed to restore a single example to flight status to take part in the Battle of Britain memorial flight. The recent Platinum Jubilee celebration for Queen Elizabeth II featured a mixed squadron of Spitfires and Hurricanes in the fly past, plus a Lancaster-all Rolls-Royce powered.

@jacktattis

2 ай бұрын

Well apart from the Beaufighter Spitfires /Hurricanes were Merlin powered

Great video! I've always known that there sometimes are other ideas, products and inventions that were brilliant but took a back seat to the most known ones. Politics, greed, dishonest business might be some of the things that kept them fairly unknown. Thanks for your research!

Good job sir.

The Merlin engine was a great engine, but it gets waaay too much credit. If there was an engine that “won the war”, or powered more allied aircraft than any other, it was likely the Wright Cyclone family of engines. Not particularly glamorous, but a total workhorse of a radial that powered numerous different allied aircraft during the war.

@thepewplace1370

2 жыл бұрын

I'd argue the P&W engines had a greater effect. The point of allied air was destruction of enemy air forces: bombing was a secondary component to this. P&W R2800 powered aircraft were responsible for the destruction of both the Luftwaffe (P51 arrived when the Luftwaffe was already severely depleted of talent) primarily with the P47, and destruction of the Japanese air forces in the post-Midway march towards Japan with the F4U and F6F.

@richardrichard5409

2 жыл бұрын

@@thepewplace1370 spot on👌

@SillyPuddy2012

2 жыл бұрын

@@thepewplace1370certainly the P&W Wasp as well, but the role of heavy bombardment (on factories and infrastructure) - in addition to troop and supply transport cannot be understated. Basically most all the US planes powered by either the Wright or Pratt&Whitney.

@hadial-saadoon2114

2 жыл бұрын

@@thepewplace1370 And the R-1830 Twin Wasp powered dozens of multi-engined aircraft, including 18,000 B-24 Liberators with incredible reliability. Over 130,000 were produced. Wright's R-1830 was a great engine in the same class of 1200 HP, but other than the larger R-2600 it sank into grief with the R-3350 and it's overheating problems until after the war was over.

@AsbestosMuffins

2 жыл бұрын

the cyclone and wasps, also the continental. The big insane engines the brits made are great but US radials were equally insane

Nice job! Well done. And thank you for this video.

Thank you for the awesome commentary.

Definitely seems like an incredible piece of kit but also somewhat obvious why such a power-plant wasn’t more wide spread. As you described it it sounded a lot like an F1 engine lol. So high complexity highly stressed high chance of failure. The operating RPM alone being a third more than that of its contemporaries is quite telling of the potential rate of wear such a system must have undergone, while in 1940? When oil was about as viscous as sand paper? A lot of power from a lazy under-stressed engine sounds definitely more military, for the redundancy, reliability, and opportunity to use. Napier Saber sounds more racing motor than warplane

@arkhsm

2 жыл бұрын

Sabre !!

Rolls-Royce were told well before WW2, that smaller faster revving engines would be less stressed overall and more powerful in both bhp per litre and bhp per unit weight. They ignored the thinking and came close to failing with the Merlin. Centrifugal forces on the large crank threw oil out faster than the oil pump could feed it in. Smaller cranks can spin faster. It's not necessary to push all the power through one cranks, so why not use two or even three (thinks Deltic).

@robertmoulton2656

2 жыл бұрын

Doesn't high reving engines usually sacrifice torque ?

@alexxu3004

2 жыл бұрын

@@robertmoulton2656 If everything else is equal then it depends on where you want the torque. high rpm engine will have MORE torque at high rpm, and LESS torque at low rpm compare to a low rpm engine. on a piston aircraft propellers are almost always running at highest torque rpm range as you can change propeller pitch so its not important to have low range performance, your day to day driving car on the other hand is the opposite

@NullHand

2 жыл бұрын

@@robertmoulton2656 Power is the product of torque times RPM. Gears are the devices we use to swap between RPM and Torque at a given level of Power production. Engines will run into some physical constraint on either the Torque or RPM extremes, but generally high RPM designs are easier to optimize for high power to weight ratios. This ultimately led to turboprops commercially replacing piston props. Power to weight ratios of extreme RPM operation more than offset the weight of massive reduction gear ratios to deliver the high torque a prop requires.

@robertmoulton2656

2 жыл бұрын

That explains why semi truck engine spin 8/9 thousand Rpm .

@NullHand

2 жыл бұрын

@@robertmoulton2656 Semi truck buyers care far more about fuel efficiency than power to weight ratio. Mostly because wheels on the ground handle excess mass far better than wings in the air. Big slow engines are more fuel efficient. Ocean going freighters even more so. One of their pistons can be bigger than an entire semi engine.

This was fascinating to learn - especially for a non-engineer such as myself. Still a little fuzzy on the moving cylinder sleeve setup, but still awesome interesting to learn.

Nicely done documentary. Professional jealousy between firms has held back more promising designs than I dare count.

Thanks so much once again! I didn't realize the nastiness/ rivalry that happened between RR and NS. It also explains why I have had some ingrained Bias against the NS engine! I'm 67 and still learning. Thanks again and well presented! I also wonder how the German Engines would have gone if they got real 100 -150 Octane gas ! But as the song goes Ï wonder, wonder who who wrote the book of love! We are fickle creatures..... thanks again

One figure you missed was the production cost of a Sabre. A Sabre costing on its own considerably more than a complete Spitfire with Merlin.

@somebloke13

10 ай бұрын

Quality doesn't come cheap!

I first learned about this engine playing War Thunder years back. The H (which isn't a boxer like everyone says it is) 24 was my favourite configuration after that.

@BuzzLOLOL

2 жыл бұрын

The H was from combining two semi-boxers together...

@690_5

Жыл бұрын

@@BuzzLOLOL Exactly, they always think it's a flat engine one crank. It's two flat engines with two cranks

In 1964 I began my schooling for an A&P mechanics license. Our very knowledgeable powerplant instructor did not include the Napier Saber engine in the syllabus because he knew that we would never see one outside of a museum. He did, however, describe it to us, and told us the of engine's performance. I can remember exchanging glances with my fellow trainees, wondering if we should believe him. That is how far out of the mainstream the Sabre was.

Napier seemed to specialise in unusual engine configurations. X- , H- , W- and even triangular. No bog-standard V- , except as a subcontractor.

@stevie-ray2020

Жыл бұрын

It was great that Napier were prepared to 'think outside the box', but making things more complex brings to the table other considerations such as weight, cost, reliability, durability, & maintenance!

Incredibly interesting video and even worthwhile comments, unfortunately the graphs were meaningless for me as the script was far too small for me to read, a great shame as the comparisons would have been informative, overall a very good watch that even touched on the political side, something often overlooked.

@flightdojo

2 жыл бұрын

sorry about that Roger, next time I'll make them larger

@CrusaderSports250

2 жыл бұрын

@@flightdojo thank you for that☺.

@flightdojo

2 жыл бұрын

Im making a second part to this series with larger font on the graphs!

@Mapster2001

2 жыл бұрын

I’m on mobile, 720p, and can read everything without my glasses well enough to understand and not struggle at all…

@CrusaderSports250

2 жыл бұрын

@@Mapster2001 I feel very happy for you! , unfortunately in my case those days are gone, but I still enjoy finding out things and learning something new, a slightly larger format would greatly help and the gentleman posting has acknowledged this and for that I am grateful. The tone of your post almost seems to be one of mocking someone less able than yourself, and if so then shame on you.

Thanks for a great video!

Thank you for your most excellent vids! After watching the second part of this vid youve changed my perception of the Sabre, mainly it was troublesome, prone to overheating and fond of gassing its pilots. Did make me wonder what if they had basically made half a Sabre, A flat 12? Around half the weight, and hp, but still around 1200 mark. The advantage would be the nacelle wouldn't be much thicker than the wing and would be comparable power to others that were in use and suit most twin engined aircraft of the day, Beaufighter for instance? Finally imagine a DeHavilland Mosquito or Hornet with Sabres! Thanks again.

If hp/wt was the only metric for judging aircraft engines, then the Napier would have been in every airframe. For military aviation ease of maintenance and reliability trumps power to weight every time. It's really simple: more parts = less reliable. The science of metallurgy was always a few years behind the imaginations of engine designers. Just the gearing and bearing count alone made these W or H engines a maintenance nightmare no matter what company built them. The higher the horsepower shrunk the time between overhaul. Even today a 4 cylinder Lycoming that is turbocharged has half the service life of a normally aspirated version. In the case of high revving engines, the gearing required for best propeller performance chop the service life. It wasn't interference by Rolls-Royce that prevented Napier success. It was its own complexity.

@keithstudly6071

2 жыл бұрын

I think you have a good view on the Saber. About high RPM operation, this was limited by the sleeve valve design as the whole cylinder was in motion and that is a complex and heavy assembly and produces a large amount of friction. The Saber was a fuel hog and an oil hog as well because of the sleeve valve design. The best comparison for the Saber was to the Bristol radials which were much more successful. More than that the sleeve valve design was copied from Bristol as they had better luck in making it work. I wonder why cost was not mentioned? Do you think the Saber was inexpensive to build compared to the other engines? Also I wonder about the TBO on the Saber? How was it compared to other engines?

@theinspector1023

2 жыл бұрын

It's Sabre not Saber. Wherever you come from that was the name of the engine. And I think there were rumours of sabotage by R-R 'sponsored' mechanics - for example ensuring a combination of high boost and coarse pitch at low altitude. Then again..... Thanks for the film. Now it's time to watch Curious Droid's piece on the Napier Deltic, another brilliant engine and another excellent study. What a company!

@BuzzLOLOL

2 жыл бұрын

@@keithstudly6071 - Sleeve valve engines have many of the same engine life, fuel consumption, oil burning, and emissions problems of 2 cycle and rotary engines... plus all that extra weight and complexity...

@autodidact537

2 жыл бұрын

Hours of maintenance per hours of flight compared to the other engines wasn't addressed in this video. Who cares how powerful your engine is if it's always in the shop?

@BuzzLOLOL

2 жыл бұрын

@@autodidact537 - Probably like a Top Fuel Dragster... expect a full engine rebuild after every flight...

The success, failure and production preference for aero engines is more than just a few graphical representations. Production complexity, squadron line maintenance, specialised materials, parts supply industry, special tooling also weigh heavily. Comparing other contemporary engines to the Sabre need to balance these factors as well. Sabre was an excellent engine in many ways, but not all.

@flightdojo

2 жыл бұрын

That’s a fair sentiment that I address in part 2. Part of the challenge in ranking these engines is, like you say, there are multiple factors at play that dictate the reputation and perception of an engine. In this case, while maybe simplistic, I’m using the term “ultimate” loosely to reference power output alone.

Have you added "Allied Aircraft Engines of WWII" by Graham White to your library? Excellent discussions. One of the interesting technologies that the Sabre advanced concerns the reduction gear drive that connected the two crankshafts to the single propeller shaft by way of twin idler gears of each. The backlash of the gears were managed by using helical cut gears and allowing the idler gears to slide on their shafts, but with each pair interconnected with a "teeter totter" link so they evenly shared the load. Then the gas turbine came to being based on the same technologies needed for the turbo superchargers and turbo compound power recovery turbines and blew all the reciprocating engines out of business with power to weights and operating economies that were in a class by themselves.

Napier also built the Deltic engine, which was used on ships and railway locomotives. It was high revving and complex too

@douglasgreen437

Жыл бұрын

& a 2 stroke diesel to boot...

Great Video! The Napier Sabre is my hero engine. By the way is there any one still working?

@apostlestumpy

2 жыл бұрын

There are a couple of projects to get both Typhoons and Tempests airworthy including Fantasy of Flight and a gentleman in Canada building a Typhoon from scratch, his channel is Typhoon legacy.

They had serious quality control issues from what I have found. Not fixed until under new ownership. Sloppy assembly and metal cuttings in the engine, if true, trumps all the hype about RPM, power to weight etc. Engine failures in A/C cause more than an inconvenience can’t pull over and curse and kick a tire. Even a partial engine failure is a serious emergency in an aircraft. THIS I have experience with.

@timengineman2nd714

2 жыл бұрын

Almost all British Engines were hand fitted! Spare parts generally had to be made big and you sawed or filed metal off until it fit!! (Or in the case of some parts you had up to 7 part sizes (3 smaller, 1 average, and 3 larger) and you had to order the right one. I've had the same experience on one (built by the lowest bidder and the parts "fitted" that way, where it took a few tries before we found a +1 sized cylinder liner that actually the block AND the piston! We were able to deliver the engine back to the ship "only" 3 days late!

@promerops

2 жыл бұрын

I have read that the source of the early problems with the Sabre was to do with the sleeve valve tolerances. Napier were unable to achieve the precision required and the machining of the valves was farmed out to Bristol - who had the necessary expertise gathered from their own Centaurus engine.

@daverobert6761

2 жыл бұрын

A good friend of my father’s was killed when the Sabre in his Tempest cut out over the channel - he was never found.

@alastairbarkley6572

2 жыл бұрын

Hand fitting produces incredibly tight tolerances - far more exact than the mass production pioneered in the US. But, parts from a hand fitted engine would not (guaranteed) fit any other engine of the same type and hand fitting requires highly skilled engine assemblers. American mass production engines needed much lower worker skill levels. It's the contrasting visions of the two Henry's - Ford and Royce. Is the American system better in time of war? Probably, yes - but, RR built 2/3rds of wartime Merlins, Packard, only 1/3.

@timengineman2nd714

2 жыл бұрын

@@alastairbarkley6572 Exactly, plus the amount of time to do this is ridiculous!!! The time it takes to train someone how to do this accurately, the time to constantly replace tools for the squadron's maintenance crews (since they do wear out!) and the time to actually hand fit parts when the squadron needs every possible plan in full working condition!!!!!! (Rolls Royce and Avro made the "power egg" for the Lancaster so they could swap out engine and radiator assemblies quickly and repair whatever was wrong and still keep the bomber flying...)

Great video I didn't know about the Rolls Royce smear campaign but it makes sense. Every time the Sabre is mentioned it's teething issues are always brought up. I also love the Tempest mk V

Good stuff as always :)

Flight DoJo, good video, but you never mentioned its biggest problem, (other than its reliability issues,) its terrible overheating problem that came from so much HP. The Typhoon's massive "Chin" radiator made it very vulnerable to AA fire and it suffered worse losses than Bomber Command's heavily bombers.

@w8stral

2 жыл бұрын

All one has to do is look at P47 vrs P51 numbers for loss ratio to sortie and flight hour by year flown. P47 had 3X lower loss ratio even though IT was tasked with ground pounding and bombing while the P51 was NOT. P47 in fact had lower loss ratio than both the Mosquito and the P38. Difference? Air cooled Radial engines are vastly superior to non air cooled engines(yes some radials were liquid cooled).

Thanks for your work, research and video...I remember when I went to Duxford airshow a few years ago and the green static Napier engine was displayed (actually the one in this video) and we cranked the handle to see the valves working I was amazed at how it worked...I can only imagine that there must be issues with manufacture (expensive to make maybe) or design (cooling issues maybe) that make the sleeve valve redundant today...Does anyone know of a contemporary engine that employs the sleeve valve technology and if no then why no engine manufacturer makes it?

@BuzzLOLOL

2 жыл бұрын

Well, short service life, high oil consumption, dirty exhaust killed it... sleeve valve engines were used earlier here in Toledo Ohio USA for the Knight motor car...

@tuck6464

2 жыл бұрын

I think Koenigsegg had, (a couple of years ago) or were developing, something called a valve less engine/ head . Although, it's a hypercar manufacturer and wouldn't be considered mass produced, I believe, (after seeing this) that they may have been borrowing some of those principles. I'm not sure if they ever followed through on developing it or not. I could be wrong.,

@loddude5706

2 жыл бұрын

H24 eh? Try sending Allen Millyard two dozen Honda fifty engines & a Royal Warrant for 'The Jubilee 1200' (Sorry : )

@autodidact537

2 жыл бұрын

Sleeve valve engines are notorious for burning a lot of oil.

@elizabethburgess7671

2 жыл бұрын

Don't know of any currently produced sleeve valve engines but FWIW Cosworth seriously considered a sleeve valve engine during the initial design work that eventually produced the F1 Cosworth DFV engine instead. My understanding of the reason for it's demise includes that the issues it was designed to overcome were overcome in different ways, e.g., better fuels with higher octane ratings and the development of the sodium cooled poppet valve all but eliminating the issue of the hot exhaust valve causing premature detonation of the charge in the cylinder for example.

An extraordinary company with an amazing portfolio of engines inc the deltic and the bizarre but brilliant Nomad

I like the theory that Napier didn’t get into jet engines because they weren’t complicated enough. That they pursued the Nomad compound engine for so long suggests the theory has some validity. The early use of the Sabre in the Typhoon suggests that it hadn’t be fully developed, i.e. the placard on one Typhoon “If the engine catches fire, don’t just wave your arms at the pilot, try putting the bloody thing out!”

Maybe the Sabre's initial hurdles were due to it looking like a big cubic factory object rather than a classic V or radial engine. That's how it impressed me when I saw the one in the museum.

Napier is pronounced NAY-pee-ur. The Rapier engine was pronounced RAY-pee-ur, like the sword.

@chrisjohnson4165

2 жыл бұрын

Yes! Nearly every video lately has howlers like this.

@flightdojo

2 жыл бұрын

Thanks, many have commented about the poor pronunciation. I'll make sure to avoid this mistake in future videos.

Great research and information. You mentioned about why larger displacement may not increase weight. I am thinking .. big cylinders.. are empty spaces that dont contribute to weight, but do contribute to power output.. obviously the crank and rods must be strong enough to take whatever the power output is. I wonder if the Napier would have done even better with big boost, less cylinders and lower rpm, but keep the very efficient valvetrain. I bet that engine sounded amazing at high rpm and load...

These are awesome videos keep em coming please.

An interesting video on the Sabre engine, it did have a difficult development because of problems with the sleeve valves and undoubtedly with the Tempest V below 20,000 feet because the supercharger was limited, was the best allied fighter for a period. Indeed the Meteor III performance was measured against Tempest, and it was the nemesis of the ME 262, to the point they were forbidden to go below 12,000 feet over the combat area. However, it was bypassed by the arrival of the Heavy weight Spitfire Mk XIV which even the Luftwaffe recognised was the most superior Allied fighter at the end of the war. The Ministry of Aircraft production continued with Rolls Royce for a while with the development of it’s successor Crecy, but it became clear that the Centrifugal compressors jet engine was far superior with greater output from few parts and less cost. It understood the ministry of aircraft production spent £2M for the development of sleeve values, to put that in context, HMS Ark Royal cost £3M without aircraft, the KGV battleships around £6M each.

@BuzzLOLOL

2 жыл бұрын

The rotating jet engine was going to last more miles than a reciprocating engine... but the early jet engines were fuel hogs... until the difficult science was available to make it more efficient...

@andyharman3022

2 жыл бұрын

Yes, it's sad that the Sabre didn't have a 2-stage supercharger available for the Tempest, but it proved to be very effective in running down V-1 buzz bombs late in the war. Flat out, down on the deck, there was no better aircraft for the job.

@Jyrgenstrator

Жыл бұрын

​@@andyharman3022 It actually had 2-stage supercharger.. At least in every sim I have flown it in.

I recall seeing a cutaway when I lived in the UK early 80's - maybe in the Science Museum but I can't recall now. Horrendous complexity was on show and that must be a down tick for it. Even in war time costs and maintenance matter. My dad was permanent airforce when WW11 began and transitioned from English stuff to Allisons, Wright Cyclones and PW2800's by war's end. He much preferred the American engines to work on.

@johncrowley5612

2 жыл бұрын

The T.B.O. of the Bristol sleeve valve engines exceeded that of all poppet valve engines. Once the great Roy Fedden helped Napier resolve their initial sleeve valve reliability problems the Sabre started to exhibit similar long term reliability. Mechanics favoured. U.S. radials because of the very simple repair procedures for a lot of problems. e.g the simplicity it of changing a cylinder/piston with the engine in situ.

@billwilson3609

2 жыл бұрын

Your dad had to be pleased after discovering that the Allison was built with 50% fewer parts than the Merlin with all replacement parts being a direct fit with no hand fitting required.

@danieldonaldson8634

2 жыл бұрын

My Dad was in WW06 and WW10. Could never get his mail delivered.

The port-flow numbers and trapping efficiency tell the story. Raw boost alone is never the final determinant.

Loved it! You did an excellent job of portraying this fascinating engine. I first heard of it when I read The Big Show by Pierre Closterman. ❤

Very interesting story of this complex and successful engine. Napier's had made a turbo charged version of their W 12 Lion engine which was successful. It is surprising they did not design a turbo charged poppet valve V 12 engine which should have had the best power to weight and power to displacement ratio I guess they could also have designed and made a poppet valve V 12 engine with engine driven superchargers running at higher RPM and BMEP to produce 2000 BHP. High Octane fuel and the design of the Supercharger would have been the key to success. I feel they were fixated by volumetric efficiency which is improved with sleeve valves at the expense of weight complexity and cost. Manufacturing the Sabre's sleeve valves caused problems which were eventually solved by Bristol who used the same valves on their Radial engine. In turn Napier's sorted our the problems Bristol had with the complex gearing on their Radial engine. They ended up with a complex over weight design with the Sabre which required a great deal of development work to achieve a good result. The Sabre is a mechanical engineers marvel with all its complexity and should be held up as an example of determination and patience . Napier and Hawker came together to produce the most effective ground attack aircraft towards the end of WW11 . It was feared by the enemy and helped greatly in ending hostilities.

@flightdojo

2 жыл бұрын

my guess is they were unaware that sodium cooled poppet valves was being developed when they were searching for ways to bypass the theoretical 1500hp limit on traditional poppet valves... not sure on that one though

@somebloke13

2 жыл бұрын

There will always be a limit on air flow with poppet valves. The valve size is limited by cylinder bore diameter, which determines the combustion chamber size. The Sabre was making over 1000bhp more than the Griffon on the same fuel. Unless you get into exotic fuels, there is a limit to how much boost you can use before detonation become a limiting factor. Given there was a war on, big power from whatever fuel you could get your hands on was a big advantage.

@johncrowley5612

2 жыл бұрын

@@flightdojo The Wright J5 Whirlwind of 1925 used sodium cooled exhaust valves. Lindberg used this engine to cross the Atlantic. Napier were certainly aware of sodium cooling of ex valves.

Interesting video. There's a lot here I didn't know about the Sabre. I think I can offer some technical maybe insight, based on my own amateur speculation. Concerning the Sabre's high weight for its displacement, that makes a lot of sense based on its design principals. I doubt the two crankshafts are the main factor, since both a V12 and an H24 have two cylinders per crank throw, so they're about equally weight efficient there. Instead, take a look at the cylinder dimensions. The Merlin had a 5.4 inch bore and and a 6 inch stroke (an undersquare cylinder), whereas the Sabre had a 5 inch bore and a 4.75 inch stroke (oversquare). The Sabre cylinder has both a much shorter stroke to bore ratio, and it's smaller (much smaller in terms of displacement, which goes as the cube of any linear dimension). Longer strokes and larger cylinders are simply more efficient in terms of structural weight. You need to add a lot more metal to get an extra inch of bore than an extra inch of stroke. All containers become more weight efficient with larger size because of the square-cube law. If Sabre was also designed from the start both for a higher power density and higher RPMs, Napier would have needed to go for heavier construction to achieve similar longevity. So all in all, the Sabre's high RPM (and the small, oversquare cylinders which made that possible) and its high power density intentions lead to a higher structural weight per unit of displacement. The trick, naturally, is to make the power go up by a greater factor than the weight. We can see just the opposite design approach with your figures for the R-2800. A big air-cooled radial is maybe the best common design for getting a lot of displacement out a small amount of weight. Big, long-stroke cylinders are, again, more weight efficient. A radial puts a lot of cylinders around a small and short crankcase and crankshaft. Air cooling removes the need for a cooling system, cooling jackets, etc. On the other hand, the R-2800 has a poor specific power. Air cooling becomes a constraining factor at high power densities. Making more power inevitably produces more heat, and liquid cooling can simply remove more heat than air cooling. Overhead cams are also impractical in radials, so they're usually limited to two valve heads with not very optimal designs, and that along with the long stroke, limits RPM, further hurting specific power. As for volumetric efficiency, it's probably very hard to get good figures on that, and even then, the circumstances under which they were determined may not be comparable, but I really doubt that they differ much between these engines. Any engine designer with high performance intentions has to fail pretty hard not to achieve a high volumetric efficiency at his intended operating RPM. The trick is, which RPM. The huge, unobstructed ports of a sleeve valve design would be great for shifting the peak volumetric efficiency up to a higher RPM, unlike poppet valves which partially obstruct the ports even when open. So the Merlin could achieve a high volumetric efficiency at 3,000 RPM, but at 3,800 the poppet valves just wouldn't be flowing enough to efficiently fill such large cylinders, even with four of them. Of course modern engines do breath through poppet valves at much higher RPM, but they also have much smaller cylinders and technology has just advanced. The R-2800, with even larger cylinders probably wouldn't have been able to go much above 2,700 RPM structurally anyway, so even with only two valves and the non-optimal placement dictated by push-rod actuation, it would still be able to flow enough to achieve good volumetric efficiency at its low operating speed. I think you're also understating the difference between a 7:1 and a 6:1 compression ratio. That's actually pretty huge both for power output and fuel efficiency. Poppet valves were often a limiting factor there, with designers going to extremes like filling the valves with sodium in order to avoid hot-spots and detonation, so having no poppet valves may have helped the Sabre there as well. So we can probably say that the Sabre's power is mostly related to its RPM, displacement, compression ratio, and how much manifold pressure the supercharging system can produce, and all the other design features, like H-24 layout, small, oversquare cylinders and sleeve valves, are what allows it to achieve high RPM in such a large displacement. At some point, detonation might start to limit manifold pressure, and at that point, the lack of poppet valves may become an advantage to delaying detonation, but it sounds like the Sabre never really got the point where detonation could become a limiting factor anyway.

Excellent video. Well done. I'm a Rolls Royce and P-51 fanboy. This engine is an astounding design for the 1930"s. If they had the materials then, that we have now, this engine might have had a more illustrious history. One question that occurred to me was about the brake-specific fuel consumption compared to the other engines.

@AtlasLathe

2 жыл бұрын

You would think it would have better efficiency due to the better airflow to the cylinders. However the frictional Loss due to the complex sleeve valve assembly may make it worse. Why has no modern sleeve valve engine been built for racing?

@specialingu

2 жыл бұрын

@@AtlasLathe possibly rules...

@HerrmannThompson

Жыл бұрын

As far as I know a Tempest or Typhoon has above average range due to a high cruise speed, but this comes at the cost of a relatively higher fuel consumption as well, so range was good, loiter time was not. One thing that was quite bad was OIl consumption though, I forget the exact figures but a Sabre would consume unreal amounts of oil while running due to its design.

Excellent vid - thanks.

Interesting. One of my favourite engines. Napier had severe quality control, reliability and management problems in the early part of Sabre. production. One other problem which many forget is engine cooling. As power increased radiator size had to increase in line. I always wanted to be in on the meeting where the Sabre or PW man extolled the virtues of their complex engines with hundreds of parts - the Swiss watch of power production - and how many horsepower does your engine produce Mr Whittle? - about 2,750 - and how much does it weigh - 1000lbs - ah but how many parts does it have??? One ! - I would love to have a photo of the piston men's faces.

@jlabreu1

2 жыл бұрын

Great way of looking at it.

@christopherhughes2211

2 жыл бұрын

Really for comparison it’s philosophically true but in fact of course there were numerous parts in the whittle engine and unlike piston engines early jet engines had ludicrously short operation times before total rebuilds. At the time they just didn’t have the hi temp metallurgy to run them for very long without catastrophic failure, at least that is my understanding from numerous materials I’ve read from after the war.

@turboconqueringmegaeagle9006

2 жыл бұрын

@@christopherhughes2211 metallurgy and technique, things we consider obvious now like blade root design took time to develop which is why the more successful early engines used centrifugal designs which are inherently sh1t.

@chrischamberlaine4160

2 жыл бұрын

@@christopherhughes2211 You are mixing your English and German history. Read Jet - the book on Frank Whittle and look up Nimonic I also recommend Gas Turbine Engines by Gunston. These will set you right on the development of the technology in Germany and England. Very different. And keep your sense of humour.

@chrischamberlaine4160

2 жыл бұрын

@@christopherhughes2211 As a matter of interest - W2B-700 - Combined design based on W.2B/500 and Rover B.26 for Meteor III. Straight-through development of the 'trombone' style W.2 configuration, using already tooled-up compressor casing for Welland, new RR diffuser, and with compressor and turbine air and gas flow increased by 25% to give 2,000 pounds-force (8.9 kN) static thrust. First tested July 1943. Type-tested to 500 hours, into service for Meteor III at 150 hours TBO. Jumo's could only manage 10 hours service and 25 hours before failure.

Interesting engine. Much too complex for wartime applications. Give me a Pratt and Whitney R2800. Simple, easy to maintain by any 18 year old mechanic and the last variants produced 2800 horsepower! Also used in the P47M which was capable of 500mph or better. Bulletproof literally and used in a huge variety of aircraft. Some are still flying today hauling cargo, etc.

@rdallas81

Жыл бұрын

Best engine of the war IMO.

I have the book of LJK Setright "The Power To Fly" and I think you read that too. Life was not easy for Napier. The Sabre was a great engine. There is also a Nomad. 41 liter 12 cil boxer diesel 4000 hp

Awesome video thanks for sharing this with us really good to know this

I was an engine machinist for 30 years and I cannot understand how anyone can call asleeve valve engine good! these engines were litterally a grenade, over engineered, not properly thought out and a disaster! IF they were SO great, why were they never used again!!???

@neiloflongbeck5705

2 жыл бұрын

Because gas-turbines took over for aircraft and on the railways the engine rpms were never higher than round 1,500 rpm (in the UK). Whilst neither cars or trucks need such power.

@Thomas-lk9ok

2 жыл бұрын

@@neiloflongbeck5705 so that's why literally the day the conflict ended ALL the typhoons and their engines were scrapped?? yet the Me 109, and Mustang werent!? even after "the age of gas turbines?"

@neiloflongbeck5705

2 жыл бұрын

@@Thomas-lk9ok the early gas turbines were had limited thrust and were slow to respond to the throttle. They also weren't suitable to certain roles. After the end of WW2 all militaries involved in the conflict, apart from the Soviet Union no longer needed large militaries and so they were reduced in size. The militaries decided to standardise on a few types that would see out their needs for the early peacetime period. In other countries, like Spain, they could not afford to modernise their combat aircraft and so older aircraft like the Bf.109 soldiered on. They were also easier to maintain than the jets coming into service elsewhere, after all what difference is there between a typical car engine of the period and a DB605? By the way the Bristol Centaurus a sleeve valve engine saw service in the skies over Korea in the MiG killing Hawker Sea Fury, so hardly never used again after WW2. The last of which retired from the Burmese Airforce in 1968.

@Thomas-lk9ok

2 жыл бұрын

@@neiloflongbeck5705 LMAO you keep telling yourself these things!

@neiloflongbeck5705

2 жыл бұрын

@@Thomas-lk9ok don't need to it's all in the history books

The Sabres sleeve valves suffered horrendously when the induction air was less than clean as a whistle, eg when operated in desert dusty environments..

@highlandrab19

2 жыл бұрын

True for many engines piston rings and fine oil channels. If the thing needs a rebuild every 60 hours in dusty environs then changing the sleeve valves too would just be another service item so not necessarily a deathknell for the engine

Talk about getting in on the ground floor, I am sub number 730! Keep up the good work!

"Under-appreciated"? You kidding, it's my favouritist engine of the war!