This animation is very good. It effectively shows how this design operates. Not all animations achieve this level of success.
@ever4437
3 жыл бұрын
Works a lot like a piston port two stroke engine. Cool engineering
@econchino
5 жыл бұрын
great animation makes the sleeve valve system very easy to understand.
@normanfawley7379
10 ай бұрын
Sir Roy Fedden,we at the Wellington Aviation Museum salute you !
@olgreywolf9688
3 жыл бұрын
Sat behind conventional Pratt 1340s for 10 years. Amazing that this contraption runs for 10 hours!! Glad I never had to fly one of these! Cam and push rod far more trustworthy!!
@HarryJohnson1991
3 жыл бұрын
T6 Harvard's?
@halhobenshield5931
2 жыл бұрын
Excellent animation!
@tedsmith6137
3 жыл бұрын
You have answered my question as to whether the Centaurus was 2 stroke or 4 stroke. Thank you.
@juanordonezgalban2278
3 жыл бұрын
It was a 4 stroke engine. As you can see the ports align once every 2 revolutions of the crankshaft.
@pilot3016
2 жыл бұрын
Excellent !!
@Kogacarlo
6 жыл бұрын
Very good.
@icanbuildit4977
3 жыл бұрын
Brilliant
@joseveintegenario-nisu1928
2 жыл бұрын
Fine art and engineering work! btw: How thick were the Sleeves in Bristol engines? Thanks. Blessings +
@joseveintegenario-nisu1928
Жыл бұрын
Charger miles 007 provided response to the sleeve thickness doubt in his videos about a Briggs&Stratton lawnmover engine changed into a single sleeve valve unit. kzitem.info/news/bejne/xGmOvmWle59-qJw Blessings +
@scoapproductions
2 жыл бұрын
Ahh. Now I understand.
@saltzen961
5 жыл бұрын
looks like a lot of overlap between exhaust and intake .
@dscott130
2 жыл бұрын
Yes, there is.
@joseveintegenario-nisu1928
Жыл бұрын
@@dscott130 mmm. Some port overlap exists in high output and many street engines, this is deliberate, to obtain top performance. I guess geometry of ports in SV can be drawn to have no overlap, but I'm not sure, this can be deducted from images in books as those by Harry Ricardo, links exist in the Wikipedia Sleeve valve article to download one of it. Blessings +
@Firebrand55
2 жыл бұрын
The questions were: did the sleeve valve engine have significant advantages over cam and push rod engines, which were far more widespread? If it did, why weren't they more widespread?
@nerd1000ify
2 жыл бұрын
They have advantages and disadvantages. Sleeve valves allow better flow at high RPM compared to a 2 valve conventional cylinder, and can run higher compression ratios due to the absence of hot exhaust valves in the chamber. The cost is more difficulty in manufacturing, tendency for higher oil consumption and more difficulties with cooling the cylinder head due to its shape. The Bristol sleeve valve radials were very successful as both military and commercial engines, but jets killed demand for large high performance piston engines on aircraft so you don't see them these days.
@aker1993
2 жыл бұрын
@@nerd1000ify you forget the Napier Saber H-24 engine.
@engnrpetev
2 жыл бұрын
@@nerd1000ify To your point about better flow, I read that one of the goals was to have more valve area than 2 poppet valve per cylinder engines and that most if not all multi-row radial engines were limited to two valves per cylinder due to various constraints.
@nerd1000ify
2 жыл бұрын
@@engnrpetev Yes that was the thinking. It is actually possible to make a 4 valve per cylinder multi row radial, the Nakajima Ha-5 series and some Alfa-Romeo engines being examples. Ironically they are actually developments of Bristol's own 4v radial technology.
They are extremely complex and many are not in serviceable condition.
@deeremeyer1749
6 жыл бұрын
So how do I get "variable valve timing"?
@seriousgoat76
6 жыл бұрын
You dont.
@planegaper
3 жыл бұрын
@@seriousgoat76 you can, by putting an eccentric on the sleeve drive, and maybe match the ports with the opening on the sleeves better for high rpm, or high boost..
@juanordonezgalban2278
3 жыл бұрын
This was used in an aircraft engine, and in this aplications the engines are used in a very narrow operational window. So vvt wouldn't be that advantageous
@joseveintegenario-nisu1928
Жыл бұрын
Not feasible with Sleeve Valve engines, as far as I know. See video by Eduardo Garcia-Sanchez, from ICAI, who updates the Rotary Engine by Jose-Ignacio Martin-Artajo, SI. Blessings +
@menguardingtheirownwallets6791
2 жыл бұрын
regular valve designs have problems with sealing the valves during compression, but with a sliding sleeve valve, that's going to be darn near impossible.
@joseveintegenario-nisu1928
Жыл бұрын
Wrong! Experience proves single SV engines had no valve leak problems larger than any other reciprocating engine. The problem you cite may have existed before 1930, but not later. Is there a 'campaing' to discredit Single Sleeve Valve engines, same as there is one against Wankel Rotary Engine? Blessings +
@captainaxle438
3 жыл бұрын
The biggest problem was the sleeve. Seizing in the cylinder. Especially if it overheated
@planegaper
3 жыл бұрын
big problems with lubrication, really.. overheating caused viscosity breakdown of the oil between the sleeves, and they would lock together, or worse, friction weld themselves together... oils of the day couldn't handle the temps.. the advent of synthetic oil has solved this.. maybe a better material with improved thermal expansion properties ( inconel x sleeves and liner ?) , and oils that thicken under heat ( al la Mercedes F1 ) could make this a viable engine ..though expensive, (maybe only use exotic materials around the exhaust ports) , a good oil cooler and super reliable pump would help too..
@joseveintegenario-nisu1928
Жыл бұрын
@@planegaper I disagree. The book by Harry Ricardo about 'The High Speed ICE', indicates that if oil film between sleeve and cylinder wall is thin enough, sleeves are transparent to heat. Mike Hewland reported no overheating in their 1974 Car&Driver interview about a 500 cc single cylinder experimental SSV engine, providing 72 HP, with an SFC of 170 gr/ HP/ hr. His engine had no specific oil supply to sleeve, splash from crankshaft was enough. Continental concluded Sleeve Valve engines were easier and cheaper to produce than popett valved engines. And it last longer, have less wear, from continued SV movement eliminates the no lubrication zone in TDC and BDC; TBO in Bristol was 3'000 hr. Wifredo Ricart, an Spanish engineer, he worked for 'Pegaso', wrote against Sleeve Valve for considerations of heat transfer, while working at Alfa-Romeo, where they conducted SV research and said 'he was a lunatic' The chapter about Bristol Sleeve Valve aeroengines by Patrick Hassell, in the book 'The piston engine revolution' explains it all about machining and alloys for sleeves. This is definitive, in my inmodest opinion. Blessings +
@joseveintegenario-nisu1928
Жыл бұрын
Where did you read about this?
@captainaxle438
Жыл бұрын
@@joseveintegenario-nisu1928 it's common knowledge that the sleeve valve engines had problems with lubrication and the sleeve if you look you'll see the grooves they put in it for oil. And it's not just normal operation it's when you have an overheat caused by lean condition or low oil all engines have problems with overheat damage some are more durable than others. Like an aluminum engine will ruin a lot quicker than a cast iron engine in an overheat. Then there's the heating and expansion of the sleeve and the cylinder I've read it many places over the years. But they were still incredible engines No Doubt
@joseveintegenario-nisu1928
Жыл бұрын
@@captainaxle438 Sorry, your information is not true. It's not same the old Knight Double Sleeve Valve engines, in Daimler, Willys, Minerva, Voisin, Panhard,...than the Bristol. It had grooves for oil in sleeve, same as Piccard-Pictet, while Bristols had flat, smooth sleeves. Please provide a reference, and look at results with Bristol Single Sleeve Valve engines during WW II. I'd trust better Tenille than Captain Blessings +
@lekvoljin7052
4 жыл бұрын
Hard to achieve efficient water cooling
@TheMagdaDar
4 жыл бұрын
Apparently cooling was not an issue. By all accounts so long as the necessary film of oil was between all the surfaces the sleeve was an excellent conductor of heat, not an insulator.
@juanordonezgalban2278
3 жыл бұрын
The cilinder head, wich is one of the hottest points in the cilinder, is much more exposed for cooling than in a puppet valve engine.
@joseveintegenario-nisu1928
Жыл бұрын
@@juanordonezgalban2278 Verdad, pero la 'junk head' es algo compleja. Los motores de modelismo RCV, del RU se parecen a la va´vlula de camisa corredera' única tip Piccard-Pictet. Funcionan. Salud +
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