Does anyone recall a quote from the German engineer Max Bentele, of Wankel fame, regarding British sleeve valve aero engines, "as requiring 100 gears too many" ? I think it's in his autobiog "Engine Revolutions" (somewhere on my shelves!).
On the subject, any thoughts on this:
Presumably it makes a difference against extreme wear in a conventional engine as compression may be better and friction minimised. Question is whether it's enough to justify the increased cost and complexity of a rotating-liner engine, particularly as something else could easily kill the engine long before any inefficiencies in a conventional design's cylinders really come into play...
I'm sure that if all that money spent in clawing slightly better efficiency out of an IC engine was instead spent on giving folk less need to use an IC engine in the first place, the world would be a better place :-)
Volumetric efficiency was higher with sleeve valves, and once the sleeve manufacture was sorted out, the limitations of poppet valves were no longer holding up engine development.
You need to think in terms of life at the high power end rather than in domestic auto engines, that's where the highest efficiencies were achieved.
Sir Harry Ricardo had a handle on the matter, as did Fedden at Bristol.
RRHT - "Fedden - The Life of Sir Roy Fedden" is a very good read:
ISBN 1 872922 13 9
Peter
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk
The RLE does not seem to feature sleeve valves. Bristol had to get, unacknowledged, help from Ricardo to resolve the sleeve valve problems.
ttfn Roland
Yes, I agree with you, a very odd idea, I envisage an engine that will drink oil - a characteristic of all sleeve valve engines and no or poor seal against compression around the sleeve which was another characteristic. History would seem to indicate that the invention of the sodium cooled exhaust valve finally killed the sleeve valve arrangement, although that idea in your link seems to incorporate the worst of both worlds!
Julian.
They repaid the favour to Napiers with supplying the liners for the first workable Sabres
re: Bristol, R-R are completely flattening the remaining parts of the Bristol factory in Filton: the area on the town-side of Gipsy Patch Lane. I wanted to get some photos of the then-exposed engine test cells from the railway line (my daily commute), but by the day or two later when I brought my camera, nearly the whole site was flat.
If you read the report:-
It's all a bit marginal - but then hard won marginal gains are all you are likely to get in such a mature technology - and personally I don't like the look of the rotating seal at the top of the sleeve in tems of durability.
NHH
On a similar note, I've always rather liked the RCV concept:-
NHH
Yep, it is all going & the four camouflaged buildings in which I spent some happy hours when Olympus 593 was in development and the BS100 sat outside my office are but memory. I wonder what they are going to do with the site? Wing production?
Development Power Plant Design (DPPD), ramjet and the flight shed gone already - little room for nostalgia when the Trent 100 is producing 75,000 lbs of thrust & the Americans are breathing down yer neck! I found this ......
Kim Siddorn
I think their proposal is to rotate the whole cylinder liner to reduce bore wear - and that the valve gear is still conventional as in any modern IC engine.
The little illustration on the left of the website page seems to show pistons and conventional poppet valves (with rotating liners driven from the crank), and the picture on the right under "single cylinder RLE prototype" seems to show a conventional head for taking poppet valves, along with a rotatable liner driven via a gear and shaft running through the adjacent cylinder.
Furthermore, they mention "proven piston and piston ring advantage of the historic sleeve valve engine", but don't actually say that they're using the liner as a sleeve valve. Shame the photo is so tiny and of such bad quality.
cheers
Jules
D'oh and yes, there it is in their PDF file, found about 20 seconds after posting that message...
Page 6, under "the RLE advantage", second paragraph: "The RLE uses conventional poppet valves..." etc.
I'm particularly wary of the boundary where the rotating liner meets the non-rotating cylinder head at the top - that seems like a weak spot where damage and/or compression losses could easily occur (doubtless just after the engine's out of the warranty period) - and it ain't WWII any more, it's not like we'd want to be tearing the whole engine apart with any kind of frequency...
cheers
Jules
Ah, hadn't found that one - it starts to make more sense now.
They make the point that most wear occurs when the piston comes to a halt at TDC - true! - and that it was discovered in WW2 that moving liners allowed the piston to continue to "hydroplane" at both TDC & BDC.
It appears to me that this is more of a problem on very large slow running engines where the piston speed is going to be progressively less the bigger they get allowing longer for the oil film to collapse. They do say that it is less of a problem with smaller engines.
Part of it actually mentions stationary engines!
Is it me or do they not make a big thing of sealing the top face?
If you have a look here:
ISTR something similar by a chap who invented a car engine that could run on water - he used some of the car's electrical power to electrolyse water and feed the resultant oxygen and hydrogen into the thing - obviously the paraphernalia consumed more power that it liberated, but plenty of investors took up on the idea. They had their day in court and the guy was exposed as a conman - I think he recently died?
Julian.
Well, at least it was scientific if not practical!
I remember reading something by "Ixion" of ancient memory when he worked for the Blue 'un (The Motor Cycle). A rather diffident & unassuming man came into the office one day (sort of 1930) & said he'd found a way of making water burn like petrol. Note the terminology. They were used to this but not used to what happened next. He produced this packet of white powder & this - with contained jocularity - the staff mixed into a bucket of processed Father Thames drawn from the tap in the lavatory. They took it down stairs, drained the tank on a staff sidecar outfit & drove it round the block. From experience, they knew that it would sputter & die as it came to a halt outside the office - but it didn't. Although it pinked like the blazes and the SV Norton ran rather hot, retarding the ignition by the lever on the handlebar allowed it to make Reasonable Progress. They spent the afternoon trying to catch him out but he just shrugged & gave them another bag of powder which they tried in another bike which they borrowed from a dealer at random.
In the end, they gave him the address of the Research Director at Pratt's Petroleum & sent him on his way, scratching their heads the while. Subsequent attempts to contact him failed & nothing more was heard of the mysterious powder or the inventor. Ixion had no explanation & could only report what had happened.
- and no, it didn't appear in an April 1st edition!
Browns gas? Sadly the internet has given a new lease of life to those dreamers who think that the laws of thermodynamics are a government / oil company conspiracy ;-)
NHH
Ah Ixion, bound to a fiery wheel for all eternity, the sort of thing I was immersed in from an early age! His motorcycling reminiscences paint a wonderful picture of that mode of transport around the turn of the century. My grandfather was a pioneering motorcyclist - denounced from the pulpit for offending public decency by daring to conduct his machine about the town on a Sunday - who, when my father expressed a desire for a BSA Bantam, declared that such small engined machines were downright dangerous and pressed an thoroughly clapped-out Brough SS80 on him!
NHH
I think that's just because their prototype was recycled from a stock
4-cylinder engine.There's also the issue that rotating sleeves in a poppet valve engine are novel and patentable, but re-popularising the oscillating sleeve valve isn't.
Were sleeve valves ever used for Diesels?
Found it! Fortunately it's only on page 5, so I didn't have to read far.
Interesting Hercules animation on ---
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