Date: Fri, 19 Jul 2002 07:45:27 -0400
Reply-To: 72510.1173@COMPUSERVE.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Helen Fahy <72510.1173@COMPUSERVE.COM>
Subject: Re: Sleeve valve engines - off subject
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Clive,
Helen & I are going to Oshkosh this Sunday. Are you by chance going?
Definitely will post the brake/wheel/light info.
Helen & Joe Fahy
'87 Westy
'46 Aeronca Chief
----- Original Message -----
From: "Clive Smith" <clive.harman-smith@NTLWORLD.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 19, 2002 6:16 AM
Subject: Sleeve valve engines - off subject
>
> >> Much better efficiency than any poppet valve engine could ever give,
and
> much more power.
>
> Thats why Formula 1 cars use them - NOT!
>
> Yes, the British took up Knights ideas in the 20's and 30's and worked and
> worked and worked and worked ... and finally, started to get these sleeve
> valve engines reliable and the oil consumption down. Bristols mainly,
> but there were others. By 1943 the numbers of sleeve valve engines flying
> over Germany daily was greater than any other type, mainly 2 and 4-engined
> bombers.
> Although the Bristol Centaurus was their ultimate engine, the workhorse
was
> the Hercules, rated variously at about 1650 - 1800 HP, by 1945 it had an
> MTBO of 3,000 hrs - an unheard of figure for a piston aero engine, and a
> military rated one at that - most others were in the 1000 hr range if they
> were good engines. These were all air-cooled double-sleeve engines.
>
> Bristol's (and one man in particular, Sir Roy Fedden) had developed the
> metallurgy, functional designs and especially the production technology to
> finally make sleeve valves reliable, efficient and powerful. I don't know
> how many Hercules engines were produced but an awful lot. Churchill
visisted
> the factory once just to see the remarkable production lines, and said
> '...without, doubt, without your engines, we could not have taken the war
to
> the Nazis in Germany as succesfully as we have ', referring to the 1,000
> bomber raids. Sir Harry Ricardo was also instrumental in the development
of
> the sleeve valve engine in the UK, as he was in almost every thermodynamic
> device of the era!
>
> The Napier Sabre 24 cylinder 'H' engine was a watercooled sleeve-valve
> engine of 2,000, 2,500 and ultimately 3,000 HP but without Bristol's being
> 'told' to make their production technology available, it would never have
> had it's teething troubles solved. The Hawker Typhoon and later Tempest
with
> this engine were the fastest of their day, the Tempest's thin-wing
airframe
> effectively combating early onset of compressibility and maintaining
> stability and control at the speeds now attainable - circa 450mph - and
> regularly being dived at over 500.
> [There are sound files on the web of this remarkable engine starting up
> (cartridge starter), taxiing, taking off and flying past - quite a howling
> monster]
> With today's synthetic lubricants matters would be a lot different, and
> easier, but vegetable oils (the sweet smelling castor bean-based Castrol
R)
> were still being used in motorcycle racing circles into the 70's, such is
> their film strength.
>
> Almost unknown, Rolls Royce (the poppet-valve kings, sodium-filled exhaust
> valves etc) were moving very much towards sleeve valves as the war's end
> approached, having 3 large development projects running for some very
> interesting engines. The last of these, a lightweight engine designed for
a
> short-range Spitfire style interceptor, was said by one RR engineer
> (responsible for its turbocharger installation) to be 'without doubt, the
> finest aero-engine even built'. Called the Crecy, it produced just over
> 5,000 BHP - and was a sleeve-valved two-stroke! 6 were built, and one
> eventually ran for 6000 hours, not only was there no perceptible wear
> detected after this, but sfc (specific fuel consumption) at altitude was
> found to be not far short of the best of the day - it wasn't designed for
> range, but lightness and time-to-height - a sprint engine. It was 90
degree
> V-12, single sleeve valve engine, the turbocharger receiving 36,000
exhaust
> pulses per minute! Note that by their nature, two-strokes and sleeve
valves
> are both much more immune from detonation problems than 4-stroke poppet
> valved engines. This was the culmination of 8 years work on this engine,
the
> original spec. being laid down by the i.c. guru of all time, Sir Harry
> Ricardo, to an air ministry requirement. RR had obviously mastered
> sleeve-valve design and production, but for the advent of and a shift in
> resources towards the gas turbines then coming off the production lines
(at
> Bristol's as well), these would have become the ultimate piston engines.
>
> Sir Roy Fedden and P&W's chief engineer became friends early on and P&W
> started several sleeve valved projects as a result, one being an in-line
> engine with separate barrels.
>
> Keith Duckworth, of Cosworth V8 fame, built a single sylinder sleeve
valved
> engine some years ago, as a technology demonstrator - apparently it's
> specific output was not far from that currently being achieved by their
> Grand Prix engines.
>
> The British Napier 'Deltec' diesel engine was developed after the war as a
> powerful railway engine (3,000 hp) and was of 2-stroke, opposed piston
> design in a triangular configuration with geared crankshafts (combustion
> chamber in a perfect uninterrupted enclosed cylinder) - variants are still
> running today, and it was also used in high-speed marine applications
> (MTB's). When I was at college we had one of these in a pumping house to
> compress the air for the supersonic wind tunnel. Some sleeve valved
engines
> are, I believe still used on the railways in Canada and South Africa.
>
> Production costs of double-sleeve and even single sleeve valve engines are
> considerably higher than the well understood engines of today, and unless
> something changes radically in the world of auto engineering, I doubt we
> shall see their like again.
>
> If you're interested in the history of these engines -
> http://www.marss.com/media/sleeve.pdf is good and Rolls Royce's Historical
> Society sell a book about the RR Crecy V12.
>
> Apparantly, some Napier Sabres 'might' still be powering unlimited power
> boats.
> Or go to Oshkosh and witness a Hawker Sea Fury's 2,500 BHP Bristol
Centaurus
> whining past - quite a sight - and quite a sound - an engine so succesful,
> it was built for over 30 years, from 1938 to 1970.
>
>
> Clive Smith
> '88 Syncro Transporter
>
> ----- Original Message -----
> From: "SpaceKommander" <jboldway@BEE.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Friday, July 19, 2002 1:09 AM
> Subject: Running on tap water - didn't work!
>
>
> > I'm angry. I filled my tank with water and tried to run it to get some
> fuel
> > economy benefits but the damn engine quit after only a few seconds on
> > running on tap water. Who thought up this idea?
> > Seriously, in 15-20 years there will be a change in engine design as
> people
> > realize designs from the 1930s are the best way to assemble and run
> > engines. Two words - sleeve valve. Everybody is familiar with poppet
> valves
> > which get roasted in exhaust gasses. WWII engines such as Centaurus and
> > Perseus and Knight auto engines of the 1930's used something called
sleeve
> > valves. It's waaaay too complicated to go in to but just say the poppet
> > tulip shaped valves which bang in to the heads were eliminated and a
> > circular sleeve surrounding the cylinder with ports machined in the
sleeve
> > and cylinder did the job. Much better efficiency than any poppet valve
> > engine could ever give, and much more power. Steel and aluminum Sleeve
> > valve engines are complicated and extraordinarily expensive. However,
> > ceramics make the sleeve valve engine seem like a likely candidate for
any
> > new engine development as they can operate at much higher engine
> > temperatures than any poppet valve engine could ever stand without
> > introducing failed valve heads or detonation due to excessive exhaust
> valve
> > temperatures - there are no "valves!" - and no shock of valves slamming
on
> > to cylinder head - a smooth sliding action. Ceramics don't suffer the
> > thermal expansion problems. Plus some things like a steel connecting rod
> > surrounded by a ceramic which puts the steel under constant stress
loading
> > can be made using concepts of SPG style pressed together cranks and a
one
> > piece connecting rod of lightness and strength. Imagine an engine
without
> a
> > complicated cooling system. Ceramic sleeve valve engines also allow
things
> > such as no valve springs and operating at temperatures far in excess of
> > anything currently running as the thermal distribution is much more
even -
> > no super hot exhaust valves. Sleeves that contact the cylinders most of
> the
> > time or form a "port" to relieve exhaust without much thermal transfer.
> > That, folks, is the future of gasoline internal combustion engines. We
> > still have the 14.7/1 air/gas ratio, but operating at higher
temperatures
> > gives more power.
> >
> > Next is the conspiracy to repress the soda carburetor.
> >
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