Napier Sabre - The Ultimate WWII Aircraft Engine - Part 1

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 YouTube, 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....

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.

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.

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.

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.

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.

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

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.

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. .

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

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.

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

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

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

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.

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

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!

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

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