I work in the factory where these engines were designed & built (aero engines are still made on the same site). When I started, there were long-serving engineers there who had been involved with the Centaurus early in their careers. I was told it took a big advance in manufacturing technology to make the sleeve valves work as intended for as long as required. It entailed improvements in metallurgy, honing methods & tooling to give the durable, machined pattern necessary for decent lubrication in the sleeves.
Worked on these when I was an apprentice with Bristol Siddeley in the early 1960's. Bristol freighters normally had Hercules 14 cylinders with carbs. The Centaurus had fuel injection. Those actuators we called knuckle joints. Knuckle jonts failed if oil was not drained from sleeve valve/cylinder head gap, causing hydraulic lock. Secret was the nitrided sleeves, a Bristol Aero Engines patent, using ammonia in ovens ( No 3 shop if I recall correctly). When the ovens were opened the ammonia was overpowering if you were close; but then we were still using open trichlorethylene degreasing baths and proper zinc chromate primer; and other 'nasties' everywhere. No 1 shop was still making these engines for the French, who collected them using a Noratlas from Filton Airfield. The Centaurus test beds were next to 'Shadow Patch' , opposite the Orpheus test beds - all gone now. Seems like yesterday, but a very different world then. Just glad to have lived during that dynamic period; except the disaster to the industry by political interference. Great contnet by the way - I enjoy your videos. Still flying at 80.
I worked briefly at an aircraft engine manufacturer in the 1980s. One of the engineers there told me one advantage of sleeve valves (which were first developed by an American inventor before WWI) was that the interior surface of the combustion chamber was always in motion relative to the piston rings. On a conventional poppet valve engine there comes a time where the piston stops and reverses its motion. When that halt occurs, according to my engineer friend, the oil film tended to separate and you'd get a brief instant of metal on metal contact, before the piston ring started to drag a film of oil with it on its return journey. On a sleeve valve engine, the valve itself was still rotating when the piston was stationary and this breakdown of the oil film didn't occur. So at very high manifold pressures there was better sealing and less wear, or at least that was his view. But he also did say that the valve drive mechanism, and the many parts it took to run it, was a drawback of these engines.
According to my father in law, they were still flying Sea Furys with the Bristol Centarus off of carriers during the Vietnam War, when he was flying A-1 SkyRaiders and later on A-7s off of the carriers - so the spare parts programs were still running at least until the late 60s.
One critical point not mentioned was the metallurgical work to develop a steel for the sleeves that would expand and contract at the same rate as the aluminon cylinder yet were hard enough to keep bore wear to acceptable levels. Also, because of the design, and tight tolerances required new machining methods and machines had to be developed. All carried out under war time conditions. To the younguns out there. There were no CAD or CNC machines back in 1939 when these engines were starting to be manufactured. Over 57,000 were produced,
As I understand things and maybe wrongly, the steel sleeves were first cast using an austenitic steel, then forged in a process similar to the making of artillery gun barrels, machined to a fine finish, then nitrided. I think the working clearance from outer sleeve surface to inner surface of the low-expansion alloy outer cylinder was five thousandths of an inch but my memory may be wrong as it is years since I measured one for a film project. The castwork and precision was a delight to behold. Automotive engineering is still playing catch-up.
The development between 1939 and 1945 was amazing. This is one of my favorite engines. There wasn't a Sabre lying around there somewhere too? My ex's father used to fly around in the back of a Lancaster with three Merlins idling and one Sabre hauling it round the sky. His role was monitoring the experimental engine, he ended his career running three parts of BAE. He said that the versions they were testing at the end of the war were running over 2,800hp and over 3,000 in emergency mode.
Bristol where told to help Napier with the Saber, the sleeve vales are the same diameter and were made in the USA, Britain did not have the metal technology to make them, Napier used a lank as a test bed with the Saber on the nose.
@@aljohnson125 Not what B.C.Smith FRAeS told me when I was with his daughter. At that time he was retired from running three divisions of British Aerospace. Brian used to fly around in a Lancaster testbed. Maybe they had it somewhere else before it was flying, but that's how Brian spent is nights as a late teen. Got a link for the claims about Brostol helping Napier? Napier was a veru innovative company. Same for the statement that the UK did not have the technology, to make the parts. Sadly Brian died in the late 90s so I can't ask him.
@@aljohnson125could you please provide citations, as Bristol used KE965 which was developed in England. The machine tools utilised were purchased from the US although the reason for this is uncertain.
I was just watching this on Patreon when the RUclips version popped up. The sleeve valve engine was noted for using some what more oil than a typical valve engine. The British are brilliant mechanical engineers. Notice 3 intake valves, to get more fuel air charge into the cylinder. A brilliant design.
Years ago reading up on it I got a bit familiar about how one of these worked. I commented to my A & P mechanic dad about how neat this scheme was. He got a horrified look on his face and said, "You don't know what your are saying."
The related Bristol Hercules engine was of fourteen cylinders. Whilst it was mechanically complex, the sleeve drives ran from a single gear set in the front of the engine with some shafts short for the front cylinder row and others long for the rear cylinder row. With the 18 cylinder Centaurus, there was less workspace between the individual cylinders of the front row for long driveshafts to pass and for relay gearsets to be spaced so in effect, the designers coupled two 9 cylinder radial engines back to back. It is the nature of the sleeve valve design to burn more oil than a traditional poppet valve engine. As well as the rings on the pistons, there were rings on the "junk" head which was in effect a fixed contrapiston that the sleeve moved upon. At TDC and the instant of mixture ignition, the ports in the sleeve were hidden in the channel between the outer cylinder and the head but during the exhaust-induction cycle, the sleeve ports exposed cylinder wall oil coatings. There was also a ring fitted into an internal groove in the lower end of the aluminium outer cylinder. Transfer of heat within the engine was an issue which may not have been entirely resolved. For later iterations of the Hercules engine and likely the Centaurus as well, the working surfaces of the heads were tin-plated to solve the problem of "pick-up" which was partial seizure of the heads to the upper sleeves. This would impose severe strains on the sleeve drives. Sleeve binding could be heard in the Hercules engine of the museum Beaufighter in Moorabbin Victoria at the end of one of its ground runs. I was told but have not verified that the matured Hercules engine design, properly maintained and conservatively operated in commercial service was capable of 3000hour TBOs. Of the Centaurus design I have no information. In war service and in air racing, engine longevity is less assured. For a worker of metals, the precision and surface finish of the cylinder sleeves and their surrounding cylinders is a delight to behold.
In the early 1970's, these used to fly over our house in the Bristol Freighters from Rochford-Southend Airport, carrying cars to Le Touquet in France. They made a very characteristic sound. When I was learning to fly at Rochford, the Airport manager came in to the Aero club and asked if we could help move the Blackburn Beverley military transport, which had been on display for some years but its location was needed for a new service facility. The airport did not have a big enough tug to move it, so we decided to start the engines. It had a hand cranked mini-turbine APU, which started just fine and we left it running for a couple of hours to charge the batteries. We then proceeded to try and start the Centaurus engines. We manually propped them standing on the front end loader of a tractor and both were free. We did get one started but as we were about to try and start the second, the airport manager came rushing over to ask us to shut down. We had filled the whole airport with oil smoke and he had had to shut the main runway down. Eventually we borrowed 2 US Army 6 x 6 recovery trucks and towed it to its new location with those.
I was at Fairfax High School from 1954 to 1958, also 1312 Sqdn ATC Eastwood in those years. Type 31 and Type 32 (long nose) Bristol Freighters were in the air all the time. As a side topic, the Aviation Traders Accountant (Freddy Laker's proposed DC3 replacement) first flew from Southend Airport on 9 July 1957, scrapped Feb 1960.
I first heard of this type engine in an automobile. Good to see technology that ended up in use, however short the term. Thanks to Brian for keeping something unusual and marvelous in public eye. And to Blancolirio’s star reporter.
Charles Y Knight developed the sleeve valve engine design in 1905, his engine design was first used in automobiles and nicknamed "silent knight" because without the typical valvetrain used at the time you could barely hear it running at idle.
Correct, a few years ago I walked by an old idling car, a Willys Knight. I had walked a few steps past it, before a dim bulb lit up in my head, and I had to stay a while and ask a lot of questions.
Sleeve valves are amazing! they were set to take over before the turbine was created. the one downside of the sleeve valve was the one benefit to a turbine. how many moving parts and things can go wrong. There was never any subsequent generations and revisions like piston engines. these were only made for something like a decade if memory serves, and going to these mechanical and manufacturing lengths just didn't make sense in a turbine world, where shaft horsepower came easy
@@gneisenau89 Really?! I had no idea they were tinkering with it that early, although i guess it does make sense that they needed early experience to be able to build these. I was more thinking there was no future mass manufactured versions that I'm aware of. It would be wild to see what another 20 years would have had produced
During my time as a student of mechanical engineering i was fascinated with this type of engine. I was really obsessed to figure out how it worked. Took me three years to combine the mathematics of the sleeve valve in excel with a 3D program (Rhino3d). But in the end i had/have a working procedure where you can enter ALL relevant specs of the engine in excel and paste it into the 3D program and this "prints" the desired sleeve and cylinder geometry for further processing. If anyone has use or interest, write a comment. Sleeve Valves are really good for economics as this type of "valve" scavenges the cylinder with much less friction and the breathing of the engine is very much improved. Due to the lack of multiple red hot exhaust valves, the compression ratio can be higher for a given octane number of fuel compared to poppet valves before knocking occurs. It can even have higher RPM as there are no springs in the valvetrain. It has far fewer parts, builds more compact and needs less machining time to produce. It is a winner, right? Well almost, the weakness of this engine was supercharging. Due to distortion issues from high temperatures at the sleeves exhaust ports, the amount of pressure is limited and you cant thicken the sleeve up too much before you run into heat transfer problems. A poppet valve engine does cope much better with supercharging and the heat side effects; but it is always less efficient. The joke is, we are driving engines in our cars and even tractors and lorries which are derivatives of air race engines having excessive supercharging and power output but what we really want now is economics instead. But I can understand the car industry, investing in combustion engines is probably a lost cause and enough money goes down the drain with electric cars right now. Thanks for this channel I watch it as a most reliable source of information on aviation related topics and it certainly delivers outstanding content like this one.
I remember the Bristol Freighter from childhood. They used to be a regular sight over the skies of Wellington New Zealand as they flew between the North and South Islands up until the mid 1970s.
I am a HUGE engine guy.....known of sleeve valves for decades...this is one of.. if not thee...premier videos of concept. What will never be known by half of this marvelous contents viewers... the engineering involved...the precision of machining nessasary...... the beauty....the Bennifit of valve diameter clearence..heat dissapation...performance.....over a standard P $ W... cam traditional valve engine. As usual.. Juan put it out of the park..again. magnificent content sir. One more thing..next time I am osh...see Juan going the other way on opposing tram...risking expulsion from the greatest aviation show in the WORLD... I am jumping from my tram.....asking for forgiveness easier than permission.. regret not meeting him in 2021..bit he was going the other way.!
I have wondered how a sleeve valve works since I heard about it in a movie when I was a child in the 50’s. I had forgotten about this till you put Imm this video. Thanks so much for answering this for me.
I first heard the word sleeve valve while building a Hawker Fury modle airplane when I was 7 yo. I always wondered how they worked. (I'm 72 now) Thanks Juan, and the mericle of internet. Now I know.
Love this ! My every-time go to at the Smithsonian Air & Space museum - Udvar-Hazy annex, is the propulsion parade tucked under the stairs on the base floor. I remember working F-16 test at Edwards, and one of the engineers sharing a truism of "better aerodynamics come from better pushies".
Have been a gear head since about as long as I have a memory Juan, that means sometime about the age of 2½yrs. old, or maybe 3yrs. old, and for the life of me, I have never been able to understand the function of the Sleeve Valve, or rotary Sleeve engine design Juan ! Thank you SO MUCH for sharing that cut-away engine with us all ! A little after the fact, but please thank the owner/builder of the full scale ( actual ) engine for me ! And thank you Juan, for taking the time to bring it to the rest of us gear heads !
Brilliant video. Believed to be 34 variants manufactured and they powered the British Airspeed Ambassador passenger airliner. There’s some great footage of those on You Tube and l’ll always remember the experiences of Arthur’s Whitlock who was an Ambassador pilot for BKS in starting those engines on cold grey mornings which he recounts in the amazing book ‘Behind the Cockpit Door’. The arrival of the Rolls Royce Dart turboprop was a huge leap forward for civilian transport, supporting the production of c445 Vickers Viscounts against the c22 Ambassadors. Thank you Juan.
Grew up in Christchurch New Zealand watching Bristol Freighters come and go. On take off the tail came up real quick, and then they trundled off over the horizon. Good times.
Some 20 years ago I did see a sleeve valve engine at the Beaulieu motor museum in Brockenhurst, UK. There's a lot of other items there as well, but I don't know what has happened since I was there. If you go there, also take a look at the Eling Tide Mill a few km north of it. A museum mill driven by tidal water, it has been a mill there since medieval times. Both are worth a visit if you haven't been there.
I used to work on 'tiny little' P&W 1830's on DC-3's and thought that was a fairly complex engine - all things considered - but holy cow that's a lot of 'monkey-motion' to produce 3000hp! No wonder they were prone to break!
Well done Juan - lucid and cogent communication is what separates man from the animals. That Brian just wouldn't shut up though! Cheers - Roger from England.
Looks like a great show there. The moving cutaway engine was very interesting. If you have time on your next lay over in London, if you haven't been try the Science museum. They have a static sleeve valve engine with cutaways and probably over 50 different engines from across the ages. Also an intact V1 and V2 rocket and a whole section dedicated to space travel with a full size Apollo Command module and Lunar Module. But be warned, you will need a whole day just to scratch the surface! You can take the Piccadilly line on the underground all the way from LHR👍 You can find it here: EXHIBITION ROAD SOUTH KENSINGTON LONDON SW7 2DD
I've been to the Science Museum numerous times over the years and was there most recently only a few months ago. There's a lot of fascinating aeronautical stuff to see on that top floor, but the display of aero engines is disappointing. They are just stacked in racks with swing labels.
@@grahamj9101 Agreed they could be a little more interactive with a few more engines? But the cutaway of the sleeve valve engine taught me something I didn't know🤔 So that was one of the daily missions accomplished for an old pilot😎
@@rogerblackwood8815 The last I knew, the Bristol Branch of the Rolls-Royce Heritage Trust had a single cylinder(?) working sleeve valve demonstrator engine. Before lockdown, there was talk of donating it to a museum.
In all my 50 years of building and designing race engines for snowmobiles, motorcycles and cars I've never seen anything quite like that!! I thought the cam plate and valve actuation system for P&W radials was strange and complex, this takes the cake!! LOL I wonder what RPM it turns before reduction? I would guess not too many. Very interesting!!! Thanks Juan!!! 8) --gary
@@davidkavanagh189 ,This specific bevel-geared planetary-system has a ratio which is over 2, because the opposing stationary gear is a bit larger than the crank-gear. I guess it's about 2.5 to 1.
Just fabulous, Juan. Ellsworth Getchell, (also a TWA pilot), bought a Sea Fury and restored it. I went to Germany with him, to pick up a LOT of parts from the Luftwaffe. They used the plane for target tow. I was always fascinated by how this engine worked. It is more complicated than I imagined. Thanks for sharing!
Bevels like an old Ducati motorcycle! I remember the noise when Safe Air in NZ operated Bristol Freighters until 1986. A beautiful noise! Like an old Ducati...
From a Bristol Frightner with throttles / mixture levers like garden spades. I’ve never regretted refusing the invitation to convert onto one….especially after watching this video !!
Fascinating,i have always known of sleeve valve engines,but wondered how the sleeve was moved, this cutaway explains all, just a small rotating peg! amazing! I well remember the Silver City Bristol freighters that flew the cross chanell UK to France route and living in North London one would occasionaly be seen and heard heading toward Northolt in the 50's -60's much to the delight of us young spotters. Before i retired i worked for a light aviation company company (in the UK) who were an engine rebuild specialist, in the general office was an A65/0-200? that a couple of the engineers had fully sectioned,by full that included all of the accesories as well, carb, starter motor, filter,fuel pump etc! it was mounted on a mobile engine mount, I think after the company was taken over it got donated to a local Technical College.
Hi Juan! And to thing that it`s what? 40 or 50`s engenering?? Man. No computers, no printers, just pure mechanics. Outstanding. Happy landings from Portugal
I've heard comments that the sleeve valve engines (certainly the Bristol Hercules used on the Beaufighter) were relatively quiet. Years ago I met a mechanic who'd serviced Hawker Tempest aircraft during WW2. These were fitted with the Napier Sabre V sleeve valve engine. He said that if it backfired on start-up then there was a very good chance of snapping the sleeve valve actuators or parts thereof.
The Centaurus is really an 18 cylinder and bigger capacity version of the earlier 14 cylinder Hercules sleeve valve engine which was extensively used through out the war in many planes including the Halifax and the Wellington.. Over 57,000 of them were made. To the best of my knowledge only the Hercules was ever fitted to the Bristol Freighter.
Yes I believe that is correct, but the engine initially planned for the Bristol 170 freighter was the Bristol Taurus, another 14 cyl sleeve valve engine but was supplanted by the Hercules engine because the Taurus wasn’t powerful enough. The Taurus also had reliability issues. Bristol made several engines using this scheme from the 900 hp Pegasus through to the 2000 hp plus Centaurus.
@@johnyoung1128 The Pegasus engine had poppet valves: check out photos of an engine on (eg) Wikipedia You will see a pushrod cover in front of each cylinder. Why only one pushrod cover, when you will see two on just about every other radial engine with poppet valves? Because there were two pushrods inside the one cover: it was a unique Bristol design feature.
...The Bristol Freighter and 'Super Freighter' series used 'Hercules' engines. 14 cylinder. The Hercules and Centaurus engines used the same sleeve valve cylinder design.
Having worked with the Royal Navy's historic flight back in the late 80's, I can tell you that a Centaurus engine at full throttle sounds so much better than the Wright duplex cyclone/P&W R2800 in the Hellcat/Bearcat. It's like comparing the sound of a Ferrari V8 with a Hemi.
Brian was a real Chatty Charlie! It's amazing Juan could get a word in. A lot of work and an amazing project for a guy that apparently didn't even want to be there! 🤣
Excellent Juan. Much appreciated. I’m sure this has been said before but if they reduced the diameter of the can plate and fitted a roller/ball bearing to the actuator it may have helped but who am I to even dare to say. Once again. Thanks for your work. 👌
that'amazing have read about these engines but seeing it answers questions reading can't . these people of the greatest generation thought up these things with slide rules (for younger people google slide rule you"ll be amazed ) , paper , pencils and skill . Thanks for this !!!
I saw one of these today! It was sitting in the back of an F350 right were it was in the video.An hour before I also seen Juan.He walked past me on a mission to the pit area.Soon after he was on the show broadcasting system talking away so I guess that was the mission!
That is amazing the way it works. It looks like a two-stroke engine system or two-stroke engine or they don’t use valves either except on the two-stroke engine like a motorcycle per se those don’t rotate like these do on this engine. Very interesting.
My wife's grandfather was with the RAF. He was a powerplant mechanic and he explained to me how the Napier engine worked on the Hawker Typhoon. Same principle. I had to look it up. He later worked on the Goblin on the vampire. After the RAF he moved with his family to Montréal Canada. He then worked for Trans Canada airlines on Vanguard's, Viscount's and Canadair Northstar. It's a DC-4 but with 4 Merlin engines.
Us Brits always favored single lever control for an engine from the cockpit, whereas American engines can have 3 or more cockpit levers....throttle, prop pitch, mixture. Ours led to a more complex set up at the engine itself, especially the integrated rigging required, but it greatly simplified things for the pilot. One of the most basic was the DeHavilland Gipsy Queen engine in the Heron airplane, prop pitch was directly integrated with the single cockpit throttle lever, whilst mixture was automatically controlled by a barometric capsule in the carburettor which responded to altitude pressure and progressively leaned the mixture as the airplane climbed. The widely used RR Dart turbo-prop engine is also single lever control.
Наука
Keyboard time! All right people! STOP calling sleeve valves complex! This 18 cylinder engine has 18 sleeve drive pinions and 18 sleeve valves. Period.
An equivalent P&W will have: 4 cam rings, 36 followers, 36 pushrods, 36 rockers, 36 rockerboxes, 36 rockershafts, 36 rocker covers, 36 valves, 36 valve seats, 36 valve springs (or 72), 36 valve spring retianers, 76 valve colletts. My math not too hot, anybody wanna count 'em up???????
Agreed!
I work in the factory where these engines were designed & built (aero engines are still made on the same site). When I started, there were long-serving engineers there who had been involved with the Centaurus early in their careers. I was told it took a big advance in manufacturing technology to make the sleeve valves work as intended for as long as required. It entailed improvements in metallurgy, honing methods & tooling to give the durable, machined pattern necessary for decent lubrication in the sleeves.
The owner has such a wonderful personality
Being in that sour of a mood around Juan should be a crime lol
He's probably tired of sitting in the Sun, turning that handle and listening to people's comments all day.
Worked on these when I was an apprentice with Bristol Siddeley in the early 1960's. Bristol freighters normally had Hercules 14 cylinders with carbs. The Centaurus had fuel injection. Those actuators we called knuckle joints. Knuckle jonts failed if oil was not drained from sleeve valve/cylinder head gap, causing hydraulic lock. Secret was the nitrided sleeves, a Bristol Aero Engines patent, using ammonia in ovens ( No 3 shop if I recall correctly). When the ovens were opened the ammonia was overpowering if you were close; but then we were still using open trichlorethylene degreasing baths and proper zinc chromate primer; and other 'nasties' everywhere. No 1 shop was still making these engines for the French, who collected them using a Noratlas from Filton Airfield. The Centaurus test beds were next to 'Shadow Patch' , opposite the Orpheus test beds - all gone now. Seems like yesterday, but a very different world then. Just glad to have lived during that dynamic period; except the disaster to the industry by political interference. Great contnet by the way - I enjoy your videos. Still flying at 80.
Respect.
I worked briefly at an aircraft engine manufacturer in the 1980s. One of the engineers there told me one advantage of sleeve valves (which were first developed by an American inventor before WWI) was that the interior surface of the combustion chamber was always in motion relative to the piston rings. On a conventional poppet valve engine there comes a time where the piston stops and reverses its motion. When that halt occurs, according to my engineer friend, the oil film tended to separate and you'd get a brief instant of metal on metal contact, before the piston ring started to drag a film of oil with it on its return journey. On a sleeve valve engine, the valve itself was still rotating when the piston was stationary and this breakdown of the oil film didn't occur. So at very high manifold pressures there was better sealing and less wear, or at least that was his view. But he also did say that the valve drive mechanism, and the many parts it took to run it, was a drawback of these engines.
I worked for Bristol Aero Engines and the Centaurus was still being manufactured in the 1960’s, RB, Nova Scotia.
According to my father in law, they were still flying Sea Furys with the Bristol Centarus off of carriers during the Vietnam War, when he was flying A-1 SkyRaiders and later on A-7s off of the carriers - so the spare parts programs were still running at least until the late 60s.
Raymond, David Harding here. Canso Nova Scotia Holds many memories of my father and I. Just wanna say thanks buddy.
One critical point not mentioned was the metallurgical work to develop a steel for the sleeves that would expand and contract at the same rate as the aluminon cylinder yet were hard enough to keep bore wear to acceptable levels.
Also, because of the design, and tight tolerances required new machining methods and machines had to be developed. All carried out under war time conditions.
To the younguns out there. There were no CAD or CNC machines back in 1939 when these engines were starting to be manufactured.
Over 57,000 were produced,
As I understand things and maybe wrongly, the steel sleeves were first cast using an austenitic steel, then forged in a process similar to the making of artillery gun barrels, machined to a fine finish, then nitrided. I think the working clearance from outer sleeve surface to inner surface of the low-expansion alloy outer cylinder was five thousandths of an inch but my memory may be wrong as it is years since I measured one for a film project. The castwork and precision was a delight to behold. Automotive engineering is still playing catch-up.
The development between 1939 and 1945 was amazing. This is one of my favorite engines. There wasn't a Sabre lying around there somewhere too? My ex's father used to fly around in the back of a Lancaster with three Merlins idling and one Sabre hauling it round the sky. His role was monitoring the experimental engine, he ended his career running three parts of BAE. He said that the versions they were testing at the end of the war were running over 2,800hp and over 3,000 in emergency mode.
Bristol where told to help Napier with the Saber, the sleeve vales are the same diameter and were made in the USA, Britain did not have the metal technology to make them, Napier used a lank as a test bed with the Saber on the nose.
There are a few resto projects dedicated to the Hawker Typhoon (e.g. RB396), so we might get to see and hear a Napier Sabre in the skies again.
Think you'll find the Sabre went to 3250hp on test and was thought to be able potential to go 3700 for emergency.
@@aljohnson125 Not what B.C.Smith FRAeS told me when I was with his daughter. At that time he was retired from running three divisions of British Aerospace. Brian used to fly around in a Lancaster testbed. Maybe they had it somewhere else before it was flying, but that's how Brian spent is nights as a late teen. Got a link for the claims about Brostol helping Napier? Napier was a veru innovative company. Same for the statement that the UK did not have the technology, to make the parts. Sadly Brian died in the late 90s so I can't ask him.
@@aljohnson125could you please provide citations, as Bristol used KE965 which was developed in England. The machine tools utilised were purchased from the US although the reason for this is uncertain.
Boy ,that guy certainly wasn’t over excited about demonstrating it all…. Cool looking engine..
Agreed…. 🤦🏻♂️😳 If it were me… I would be spinning it forever…
He was so enthusiastic to share his knowledge with us.
I was just watching this on Patreon when the RUclips version popped up.
The sleeve valve engine was noted for using some what more oil than a typical valve engine.
The British are brilliant mechanical engineers. Notice 3 intake valves, to get more fuel air charge into the cylinder.
A brilliant design.
Thank Brian from me for creating this cut-away. Outstanding explanation!
Cool! My dad restored a 1927 Willys-Knight 4 door car with sliding sleeve valves. Was a very quiet smooth running engine.
That cutaway engine was fantastic. It's an easy way to understand the operation of a very complex engine.
Crazy British engineering! 3000 HP!
Years ago reading up on it I got a bit familiar about how one of these worked. I commented to my A & P mechanic dad about how neat this scheme was. He got a horrified look on his face and said, "You don't know what your are saying."
The related Bristol Hercules engine was of fourteen cylinders. Whilst it was mechanically complex, the sleeve drives ran from a single gear set in the front of the engine with some shafts short for the front cylinder row and others long for the rear cylinder row. With the 18 cylinder Centaurus, there was less workspace between the individual cylinders of the front row for long driveshafts to pass and for relay gearsets to be spaced so in effect, the designers coupled two 9 cylinder radial engines back to back. It is the nature of the sleeve valve design to burn more oil than a traditional poppet valve engine. As well as the rings on the pistons, there were rings on the "junk" head which was in effect a fixed contrapiston that the sleeve moved upon. At TDC and the instant of mixture ignition, the ports in the sleeve were hidden in the channel between the outer cylinder and the head but during the exhaust-induction cycle, the sleeve ports exposed cylinder wall oil coatings. There was also a ring fitted into an internal groove in the lower end of the aluminium outer cylinder. Transfer of heat within the engine was an issue which may not have been entirely resolved. For later iterations of the Hercules engine and likely the Centaurus as well, the working surfaces of the heads were tin-plated to solve the problem of "pick-up" which was partial seizure of the heads to the upper sleeves. This would impose severe strains on the sleeve drives. Sleeve binding could be heard in the Hercules engine of the museum Beaufighter in Moorabbin Victoria at the end of one of its ground runs. I was told but have not verified that the matured Hercules engine design, properly maintained and conservatively operated in commercial service was capable of 3000hour TBOs. Of the Centaurus design I have no information. In war service and in air racing, engine longevity is less assured. For a worker of metals, the precision and surface finish of the cylinder sleeves and their surrounding cylinders is a delight to behold.
Holly Molly, I'm old and from Bristol and you know more than me. Cheers that's the best comment I've ever read on YT. Do you have a chanel ?
In the early 1970's, these used to fly over our house in the Bristol Freighters from Rochford-Southend Airport, carrying cars to Le Touquet in France. They made a very characteristic sound. When I was learning to fly at Rochford, the Airport manager came in to the Aero club and asked if we could help move the Blackburn Beverley military transport, which had been on display for some years but its location was needed for a new service facility. The airport did not have a big enough tug to move it, so we decided to start the engines. It had a hand cranked mini-turbine APU, which started just fine and we left it running for a couple of hours to charge the batteries. We then proceeded to try and start the Centaurus engines. We manually propped them standing on the front end loader of a tractor and both were free. We did get one started but as we were about to try and start the second, the airport manager came rushing over to ask us to shut down. We had filled the whole airport with oil smoke and he had had to shut the main runway down. Eventually we borrowed 2 US Army 6 x 6 recovery trucks and towed it to its new location with those.
I was at Fairfax High School from 1954 to 1958, also 1312 Sqdn ATC Eastwood in those years.
Type 31 and Type 32 (long nose) Bristol Freighters were in the air all the time.
As a side topic, the Aviation Traders Accountant (Freddy Laker's proposed DC3 replacement) first flew from Southend Airport on 9 July 1957, scrapped Feb 1960.
That is so cool! I've seen the illustrations of the sleeve valve system, but seeing it in real time is much more informative. Thank you!
Brian's my kind of guy, I as well have had the same hat for 25 years.
I'm sure he'd be happy to tell you all about it! 😄
@@Van_Nostrand 😂👌
I first heard of this type engine in an automobile. Good to see technology that ended up in use, however short the term. Thanks to Brian for keeping something unusual and marvelous in public eye. And to Blancolirio’s star reporter.
Charles Y Knight developed the sleeve valve engine design in 1905, his engine design was first used in automobiles and nicknamed "silent knight" because without the typical valvetrain used at the time you could barely hear it running at idle.
Correct, a few years ago I walked by an old idling car, a Willys Knight. I had walked a few steps past it, before a dim bulb lit up in my head, and I had to stay a while and ask a lot of questions.
@Leif Vejby A "dim" light? Musta been one o'dem ol' fashioned incandescents!😆
@@frankhuber9912 Believe it was one of those darkroom bulbs - used to develop my own films and photos.
Sleeve valves are amazing! they were set to take over before the turbine was created. the one downside of the sleeve valve was the one benefit to a turbine. how many moving parts and things can go wrong. There was never any subsequent generations and revisions like piston engines. these were only made for something like a decade if memory serves, and going to these mechanical and manufacturing lengths just didn't make sense in a turbine world, where shaft horsepower came easy
Actually, sleeve valves were developed early on in piston engine history, with some reasonable production runs of engines in the 1920s, I believe.
@@gneisenau89 Really?! I had no idea they were tinkering with it that early, although i guess it does make sense that they needed early experience to be able to build these.
I was more thinking there was no future mass manufactured versions that I'm aware of. It would be wild to see what another 20 years would have had produced
The really were untenable as an engine- just way, way too unreliable and they were never going to fix the massive quantity of sliding friction
Turbines are great if not too concerned with throttle response and fuel efficiency at low power settings. (Which is generally fine for aircraft.)
During my time as a student of mechanical engineering i was fascinated with this type of engine. I was really obsessed to figure out how it worked. Took me three years to combine the mathematics of the sleeve valve in excel with a 3D program (Rhino3d). But in the end i had/have a working procedure where you can enter ALL relevant specs of the engine in excel and paste it into the 3D program and this "prints" the desired sleeve and cylinder geometry for further processing. If anyone has use or interest, write a comment.
Sleeve Valves are really good for economics as this type of "valve" scavenges the cylinder with much less friction and the breathing of the engine is very much improved. Due to the lack of multiple red hot exhaust valves, the compression ratio can be higher for a given octane number of fuel compared to poppet valves before knocking occurs. It can even have higher RPM as there are no springs in the valvetrain. It has far fewer parts, builds more compact and needs less machining time to produce. It is a winner, right?
Well almost,
the weakness of this engine was supercharging. Due to distortion issues from high temperatures at the sleeves exhaust ports, the amount of pressure is limited and you cant thicken the sleeve up too much before you run into heat transfer problems. A poppet valve engine does cope much better with supercharging and the heat side effects; but it is always less efficient.
The joke is, we are driving engines in our cars and even tractors and lorries which are derivatives of air race engines having excessive supercharging and power output but what we really want now is economics instead.
But I can understand the car industry, investing in combustion engines is probably a lost cause and enough money goes down the drain with electric cars right now.
Thanks for this channel I watch it as a most reliable source of information on aviation related topics and it certainly delivers outstanding content like this one.
Hawker Sea Fury rocks. I worked on Bristol Freighters in Canada back in the day.
Nice cut-a-way engine.
I remember the Bristol Freighter from childhood. They used to be a regular sight over the skies of Wellington New Zealand as they flew between the North and South Islands up until the mid 1970s.
I remember the Airfix kit, and I used to see them when I was growing up near Ringway airport, Manchester.
Fascinating example of old school ingenuity! Thanks for showing! 👍
I am a HUGE engine guy.....known of sleeve valves for decades...this is one of.. if not thee...premier videos of concept. What will never be known by half of this marvelous contents viewers... the engineering involved...the precision of machining nessasary...... the beauty....the Bennifit of valve diameter clearence..heat dissapation...performance.....over a standard P $ W... cam traditional valve engine. As usual.. Juan put it out of the park..again. magnificent content sir. One more thing..next time I am osh...see Juan going the other way on opposing tram...risking expulsion from the greatest aviation show in the WORLD... I am jumping from my tram.....asking for forgiveness easier than permission.. regret not meeting him in 2021..bit he was going the other way.!
I have wondered how a sleeve valve works since I heard about it in a movie when I was a child in the 50’s. I had forgotten about this till you put Imm this video. Thanks so much for answering this for me.
I first heard the word sleeve valve while building a Hawker Fury modle airplane when I was 7 yo. I always wondered how they worked. (I'm 72 now) Thanks Juan, and the mericle of internet. Now I know.
Wow, I thought I knew a lot about airplane engines but I never knew anything like this existed. That’s incredible engineering right there.
Wow!! Amazing engine! Thanks for sharing it, I had no idea these were once a thing.
Love this ! My every-time go to at the Smithsonian Air & Space museum - Udvar-Hazy annex, is the propulsion parade tucked under the stairs on the base floor. I remember working F-16 test at Edwards, and one of the engineers sharing a truism of "better aerodynamics come from better pushies".
Have been a gear head since about as long as I have a memory Juan, that means sometime about the age of
2½yrs. old, or maybe 3yrs. old, and for the life of me, I have never been able to understand the function of the Sleeve Valve, or rotary Sleeve engine design Juan !
Thank you SO MUCH for sharing that cut-away engine with us all !
A little after the fact, but please thank the owner/builder of the full scale ( actual ) engine for me !
And thank you Juan, for taking the time to bring it to the rest of us gear heads !
Saw you there live. To bad about the smoke. Awesome engine.
Nice to see how this engine works!
Brilliant video. Believed to be 34 variants manufactured and they powered the British Airspeed Ambassador passenger airliner. There’s some great footage of those on You Tube and l’ll always remember the experiences of Arthur’s Whitlock who was an Ambassador pilot for BKS in starting those engines on cold grey mornings which he recounts in the amazing book ‘Behind the Cockpit Door’. The arrival of the Rolls Royce Dart turboprop was a huge leap forward for civilian transport, supporting the production of c445 Vickers Viscounts against the c22 Ambassadors. Thank you Juan.
Grew up in Christchurch New Zealand watching Bristol Freighters come and go. On take off the tail came up real quick, and then they trundled off over the horizon. Good times.
That word you were looking for on the sleeve movement is reciprocate! Great video. Very informative. Thanks.
Some 20 years ago I did see a sleeve valve engine at the Beaulieu motor museum in Brockenhurst, UK. There's a lot of other items there as well, but I don't know what has happened since I was there.
If you go there, also take a look at the Eling Tide Mill a few km north of it. A museum mill driven by tidal water, it has been a mill there since medieval times.
Both are worth a visit if you haven't been there.
I used to work on 'tiny little' P&W 1830's on DC-3's and thought that was a fairly complex engine - all things considered - but holy cow that's a lot of 'monkey-motion' to produce 3000hp! No wonder they were prone to break!
Complex! Thanks, Brian and Juan.
Well done Juan - lucid and cogent communication is what separates man from the animals.
That Brian just wouldn't shut up though! Cheers - Roger from England.
Looks like a great show there. The moving cutaway engine was very interesting. If you have time on your next lay over in London, if you haven't been try the Science museum. They have a static sleeve valve engine with cutaways and probably over 50 different engines from across the ages. Also an intact V1 and V2 rocket and a whole section dedicated to space travel with a full size Apollo Command module and Lunar Module. But be warned, you will need a whole day just to scratch the surface! You can take the Piccadilly line on the underground all the way from LHR👍
You can find it here:
EXHIBITION ROAD
SOUTH KENSINGTON
LONDON SW7 2DD
I've been to the Science Museum numerous times over the years and was there most recently only a few months ago. There's a lot of fascinating aeronautical stuff to see on that top floor, but the display of aero engines is disappointing. They are just stacked in racks with swing labels.
@@grahamj9101 Agreed they could be a little more interactive with a few more engines? But the cutaway of the sleeve valve engine taught me something I didn't know🤔 So that was one of the daily missions accomplished for an old pilot😎
@@rogerblackwood8815 The last I knew, the Bristol Branch of the Rolls-Royce Heritage Trust had a single cylinder(?) working sleeve valve demonstrator engine. Before lockdown, there was talk of donating it to a museum.
Another awesome, rare, technical aviation video! Thanks for your effort!
Your engine knowledge is the best I have seen
Incredible!! Amazing to think what engineers of the day could design using a slide rule and no computers. All those gears. Looks like a giant watch.
These Centaurus engines have always fascinated me for their complexity, especially the gear train for the sleeve drives.
In all my 50 years of building and designing race engines for snowmobiles, motorcycles and cars I've never seen anything quite like that!! I thought the cam plate and valve actuation system for P&W radials was strange and complex, this takes the cake!! LOL I wonder what RPM it turns before reduction? I would guess not too many. Very interesting!!! Thanks Juan!!! 8) --gary
Hi gtr. That was a ride a half for sure.
Most of those big radials are roughly a 2 to 1 reduction. Engine turns twice for one prop rev, roughly.
@@davidkavanagh189 ,This specific bevel-geared planetary-system has a ratio which is over 2, because the opposing stationary gear is a bit larger than the crank-gear. I guess it's about 2.5 to 1.
This was the motor that powered the Hawker Sea Fury with a five bladed variable pitch prop to a top speed of 460 mph.
Great video Juan! I've never seen a cutaway of one of those, and the explanation of the engineering was great.
Just fabulous, Juan. Ellsworth Getchell, (also a TWA pilot), bought a Sea Fury and restored it. I went to Germany with him, to pick up a LOT of parts from the Luftwaffe. They used the plane for target tow. I was always fascinated by how this engine worked. It is more complicated than I imagined. Thanks for sharing!
Thank God for the turbine, couldn't imagine dealing all that. Great video
Thanks for sharing Juan! Great work on announcing the STOL Drags!!
The old dirt riders should remember the rotary disc valves 2 strokes from 50 odd years ago. A much simpler system than this aero motor.
The Centaurus is one of my favorite engines.
Bevels like an old Ducati motorcycle! I remember the noise when Safe Air in NZ operated Bristol Freighters until 1986. A beautiful noise! Like an old Ducati...
I've done two overwater flights in a Bristol Freighter, aka, 40,000 rivets flying in formation, 1968.
From a Bristol Frightner with throttles / mixture levers like garden spades. I’ve never regretted refusing the invitation to convert onto one….especially after watching this video !!
Lol! that guy was Mr. Personality.
Some people just ain't comfortable on camera.
Love the Sea Fury!
Quite a study. Can hardly imagine that thing turning a million mph. Have a nice time - thanks for sharing.
that is super interesting ! never seen how it actually worked. Amazing !
Now I know how a sleeve valve engine works! Thanks mate!
Fascinating,i have always known of sleeve valve engines,but wondered how the sleeve was moved, this cutaway explains all, just a small rotating peg! amazing!
I well remember the Silver City Bristol freighters that flew the cross chanell UK to France route and living in North London one would occasionaly be seen and heard heading toward Northolt in the 50's -60's much to the delight of us young spotters.
Before i retired i worked for a light aviation company company (in the UK) who were an engine rebuild specialist, in the general office was an A65/0-200? that a couple of the engineers had fully sectioned,by full that included all of the accesories as well, carb, starter motor, filter,fuel pump etc! it was mounted on a mobile engine mount, I think after the company was taken over it got donated to a local Technical College.
Hi Juan! And to thing that it`s what? 40 or 50`s engenering?? Man. No computers, no printers, just pure mechanics. Outstanding. Happy landings from Portugal
Wow I bet that thing sounds incredible!
Caught your announcing and commentary on the livestream today - great job!
I've heard comments that the sleeve valve engines (certainly the Bristol Hercules used on the Beaufighter) were relatively quiet.
Years ago I met a mechanic who'd serviced Hawker Tempest aircraft during WW2. These were fitted with the Napier Sabre V sleeve valve engine. He said that if it backfired on start-up then there was a very good chance of snapping the sleeve valve actuators or parts thereof.
The Centaurus is really an 18 cylinder and bigger capacity version of the earlier 14 cylinder Hercules sleeve valve engine which was extensively used through out the war in many planes including the Halifax and the Wellington.. Over 57,000 of them were made. To the best of my knowledge only the Hercules was ever fitted to the Bristol Freighter.
Yes I believe that is correct, but the engine initially planned for the Bristol 170 freighter was the Bristol Taurus, another 14 cyl sleeve valve engine but was supplanted by the Hercules engine because the Taurus wasn’t powerful enough. The Taurus also had reliability issues. Bristol made several engines using this scheme from the 900 hp Pegasus through to the 2000 hp plus Centaurus.
Correct. That gent has them confused.
@@johnyoung1128 The Pegasus engine had poppet valves: check out photos of an engine on (eg) Wikipedia You will see a pushrod cover in front of each cylinder. Why only one pushrod cover, when you will see two on just about every other radial engine with poppet valves? Because there were two pushrods inside the one cover: it was a unique Bristol design feature.
@@grahamj9101 Okay I stand corrected.
...The Bristol Freighter and 'Super Freighter' series used 'Hercules' engines. 14 cylinder. The Hercules and Centaurus engines used the same sleeve valve cylinder design.
Wow. What an impressive engine.
What a crazy design!
I knew it had to be special and you did not disappoint!
Having worked with the Royal Navy's historic flight back in the late 80's, I can tell you that a Centaurus engine at full throttle sounds so much better than the Wright duplex cyclone/P&W R2800 in the Hellcat/Bearcat. It's like comparing the sound of a Ferrari V8 with a Hemi.
Very cool and unique!
Wow!! Thank you so much for sharing!! This was extremely interesting and educational!! Entertaining too.
Brian was a real Chatty Charlie! It's amazing Juan could get a word in.
A lot of work and an amazing project for a guy that apparently didn't even want to be there! 🤣
Always wondered how those engines worked. They sound great.
I loved the 3350 because that’s what I worked on EC121K
Excellent Juan. Much appreciated. I’m sure this has been said before but if they reduced the diameter of the can plate and fitted a roller/ball bearing to the actuator it may have helped but who am I to even dare to say. Once again. Thanks for your work. 👌
Nothing sounds like a Bristol Hercules with augmented exhaust ,thanx Juan.🙂
Brownie, at my age it's not often I see a new thing. Thanks for what you do.
Thanks Juan. Great stuff.
I watched a Sea Fury at a UK airshow in 2014. Great sound.
Amazing engineering!
that'amazing have read about these engines but seeing it answers questions reading can't . these people of the greatest generation thought up these things with slide rules (for younger people google slide rule you"ll be amazed ) , paper , pencils and skill . Thanks for this !!!
What an engineering feat to design and build these engines
You come up with the neatest stuff!
Makes modern car engines look like kids toys! 🤯
I saw one of these today! It was sitting in the back of an F350 right were it was in the video.An hour before I also seen Juan.He walked past me on a mission to the pit area.Soon after he was on the show broadcasting system talking away so I guess that was the mission!
Very interesting. I had nary a clue about sleeve valves before.
A mechanical marvel/nightmare all in one.
Great video
That is soooooo cool. The Napier Sabre engine in the Tempest and Typhoon had the same setup IIRC. They ran at pretty high RPM's.
That is amazing the way it works. It looks like a two-stroke engine system or two-stroke engine or they don’t use valves either except on the two-stroke engine like a motorcycle per se those don’t rotate like these do on this engine. Very interesting.
They have one of those at the Aerospace Museum in Sacramento. It's a nice museum with a lot of interesting items and aircraft on display.
That is cool Juan!
Fascinating engine. If it hadn't been for turbines taking over this concept might have been perfected.
They have one of these at the Sacramento air museum, its a marvel to watch in slow motion.
Its a cutaway also
My wife's grandfather was with the RAF. He was a powerplant mechanic and he explained to me how the Napier engine worked on the Hawker Typhoon. Same principle. I had to look it up.
He later worked on the Goblin on the vampire. After the RAF he moved with his family to Montréal Canada.
He then worked for Trans Canada airlines on Vanguard's, Viscount's and Canadair Northstar. It's a DC-4 but with 4 Merlin engines.
Great video and a fascinating design. I would love to see footage of the cutaway R-4360 too.
Us Brits always favored single lever control for an engine from the cockpit, whereas American engines can have 3 or more cockpit levers....throttle, prop pitch, mixture. Ours led to a more complex set up at the engine itself, especially the integrated rigging required, but it greatly simplified things for the pilot. One of the most basic was the DeHavilland Gipsy Queen engine in the Heron airplane, prop pitch was directly integrated with the single cockpit throttle lever, whilst mixture was automatically controlled by a barometric capsule in the carburettor which responded to altitude pressure and progressively leaned the mixture as the airplane climbed. The widely used RR Dart turbo-prop engine is also single lever control.