Date: Fri, 19 Jul 2002 13:22:31 +0100
Reply-To: Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject: Re: Sleeve valve engines - off subject
Content-Type: text/plain; charset="iso-8859-1"
No, unfortunately not, I'm about 3,000 miles away in little 'ol England,
might be doing a bit of syncro'ing though.
I was looking at those ventilated discs, so be nice to know how good they
are - have a had a ton or so of soil in my Transporter a couple of times
this week - brakes worked, but didn't exactly stand it on its nose - I'm
sure they'd fade if I had to haul it down from 80 or 90 in hurry.
Have a great weekend, and hope you catch an earful or two of those
Centaurii, they clatter a bit starting up, but are a very reliable engine
for that power output. Great shame there are no Napier Sabres flying today -
with their somewhat disputed reliability, I don't the CAA or FAA would dream
of allowing one airborne - and theres perhaps only two examples that could
be said to be suitable for rebuilding - at phenomenal cost. If they didn't
start after the 3rd cartridge, it was a plugs out job to purge the
cylinders - '.... well, that's the first, only 47 to go!' - in freezing
weather, standing on a ladder - the realities of a frontline wartime
mechanic - no thanks.
Clive
----- Original Message -----
From: "Helen Fahy" <72510.1173@compuserve.com>
To: "Clive Smith" <clive.harman-smith@ntlworld.com>;
<vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 19, 2002 12:45 PM
Subject: Re: Sleeve valve engines - off subject
> 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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