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The service figures you quote are for engine service ratings achieved well after WW2. In 1945 they were bench figures just like the BMW801F.
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Either way the difference is marginal. Sleeves thicken a cylinder.
German engines often are quoted at their sea level power. At about 1500m their rated power will be greater than the sea level power. This is inevitable in engines that choke of the supercharger pressure. Im thinking the 801TS produced 2200 at sea level and a little higher at rated altitude.
The service figures you quote are for engine service ratings achieved well after WW2. In 1945 they were bench figures just like the BMW801F.
Great post Koopernic, there are all sorts of theoretical advantages to a sleeve valve and also disadvantages. Theoretically it could be made more powerful and more economical due to better gas flow and scavenging. In the seventies I read a sort of "what if" article which speculated that if engines had started off as sleeve valve and had been producing and researching them for twenty to thirty years all over the world they could well have been much better than poppet valve engines. If jets had not existed or succeeded then Rolls Royce were looking at two stroke designs with reciprocal sleeve valves.The sleeve valve was a response to a problem Sir Harry Ricardo himself had noted which was that poppet exhaust valves were getting so hot they would start causing pre-ignition as engine performance grew. This stimulated the development of sleeve valves in Britain some with one and some with two sleeves. There were even several automobiles in production that used them.
Sodium cooled exhaust valves, better springs and a myriad of refinements overcame the issue of the poppet valves.
At one point US researchers promoted the idea of installing a sleeve in a poppet engine to reduce fuel consumption, piston wear and pollution. Apparently the motion of the sleeve at top and bottom dead centre maintains the hydrodynamic oil film which reduces friction and prevents stiction. Oddly poppet valves had developed to the point that the idea of cutting a port into the sleeve to aspirate the engine via the anti-friction sleeve was not seen as an advantage.
The Sleeve valved Bristol Hercules and Centaurus offered no diameter advantage over the contemporary R-2600, R2800, R-3350, BMW801.
Looking at a cutaway of the Sabre shows that an enormous amount of space was allocated to the cylinder head, so much I question whether it even reduced the height of the cylinder and head assembly over a poppet valve system. The Sabres advantage may have come from the balance its horizontally opposed design offered and the high RPM this allowed.
I suspect the 3000hp Sabre probably would have given tempest a speed of around 430mph at sea level because the 2600hp version got to 410 on 150 PN fuel.
Fw 190D with plane old Jumo 213A (an engine the same weight as the Sabre were running at 2 ATA boost (about 2310hp over the 1.75 ATA 2100hp engines) so the Sabre was winning but 2.2 ATA must have been around the corner for the advanced versions of the Jumo engine which were expected to achieve 2700hp and that with a refined intercooled two stage 3 speed supercharger.
By that time jets were offering 520 mph at sea level and by the end of 1945 had exceeded 600mph. So the Sabre won a technical war it was maybe by 10%-15% over similar sized engines with single stage supercharger but that the margin would be less when inter cooling was added.
Obviously the money went to the jet.
So you don't believe ANY version of the P-47 did 500 mph?or course the premise matters. the original post made no distinction about a normal p47. it should have been pointed out as an extraordinary claim with no extraordinary proof. In what world should anybody begin a discussion of anything on a false premise.
Great post Koopernic, there are all sorts of theoretical advantages to a sleeve valve and also disadvantages. Theoretically it could be made more powerful and more economical due to better gas flow and scavenging. In the seventies I read a sort of "what if" article which speculated that if engines had started off as sleeve valve and had been producing and researching them for twenty to thirty years all over the world they could well have been much better than poppet valve engines. If jets had not existed or succeeded then Rolls Royce were looking at two stroke designs with reciprocal sleeve valves.
Rolls-Royce Crecy - Wikipedia
Good post and attachment Koopernic, I must confess when I was involved in tuning two strokes I didnt give a monkeys toss about fuel efficiency or economyIf turbojets hadn't been possible giant airliners would be winging their way across the ocean probably as 2 stroke diesels or possibly petrol engined. The usual problem with two strokes is the fuel mixture loss during scavenging. This can be overcome with direct injection. One then has the problem of determining the air fuel ratio because some of the charge is mixed with exhaust air. Using a pre chamber relaxes both octane requirements and the stoichiometric limits for reliable ignition. The pre-chamber can initiate reliable ignition while any pre-ignition or knocking is soon snuffed by oxygen starvation.
It is possible to use exhaust gas measurements to determine the airfuel ratio. I think the Merlin relied on engine RPM, exhaust temperature and ambient pressure to determine fuel rates. There was no intake flow measurement.
https://www.newcomen.com/wp-content/uploads/2012/12/Chapter-6-Hassell.pdf
It is possible to use exhaust gas measurements to determine the airfuel ratio. I think the Merlin relied on engine RPM, exhaust temperature and ambient pressure to determine fuel rates. There was no intake flow measurement.
The BMW801 is also significantly more powerfull than the Hercules. The BMW801 ended the war at about 2000hp for the 801D and 801TS at 1.62 ATA with the 801TS being able to operate at 1.82 ATA and 2350hp for emergencies. The 801 competed with the centaurus. The 801F version could have produced 2600hp.
The Rolls-Royce Vulture could have made 2500hp+ and had a diameter of 48". Well, it did on test in 1941.
The Daimler Benz DB 604 was rated at >2600hp, diameter I am not sure, but probably less than the Vulture.
The Merlin could have produced 2600hp also. The RM.17SM did just that in 1944. During tests it also ran over 2300hp (less boost, more rpm). The RM.17SM was type rated at 2200hp MS and 2100hp FS in 1945. Without ADI (which the V-1650-9 used to achieve similar numbers).
Doubtful.
Early Merlins used a carburetor which uses the air flow to determine the air:fuel ratio. Later versions used an injection carburetor - which also used the air flow to determine the air:fuel ratio.
Pressure Injection Carburetors – Typical Injection Carburetor
Also, modern engines that use the exhaust to determine air fuel ratios use a sensor which detects excess oxygen in the exhaust. This can be used to adjust the air:fuel ratio.
And, if you look at a typical Merlin exhaust installation you would notice that there are no feedback mechanisms for exhaust temperature.
Good post and attachment Koopernic, I must confess when I was involved in tuning two strokes I didnt give a monkeys toss about fuel efficiency or economyBy some strange twist of fate I ended up with one of the fastest Suzuki X7s ever raced in UK in production clases, many good racers who had switched to Yamaha RD250s asked me what I had done to it, so I asked the tuner (Terry Becket) what he did and he said "same as all the others". Even in the 1980s two strokes were still in some ways a black art. However that was just top speed, my X7 lost ten yards at least coming out of every corner, even in lower capacity classes torque across a broad range rules the roost.
Two strokes were running in to problems of safety, noise and emissions even before economy and power output became an issue.Never ridde nmotor cycles much except for a few 50cc step throughs while on holiday. They still give you that "born to be wild" song in the head. Might take up Segway racing.
In the 1990s Ralph Sarich developed a compressed air direct fuel injection system that could develop a stratified charge that was rich across the spark plus but lean elsewhere. This system could make a 2 stroke superior to 4 strokes though it is applicable to all cycles. It was perfect for two-stroke cars but entrenched conservatism prevented an uptake. It in essence worked like the crecy.
Ralph Sarich -- Fuel injector
It was taken up by Evinrude for their outboard motors, a maritime environment is not a place for valve gear. The patent may have gone to a motorcycle manufacturer.
They do use oxygen sensors and fuel sensors in the exhaust but these are required for catalytic converters anyway.
Unfortunately the theory didn't work out in practice. The Hercules being larger in diameter the Gnome-Rhone 14N/R (and the 14K derivatives ) that used the same bore and stroke. Difference in diameter compared to the Wright R-2600 was also minor although the Wright used a 4.8mm shorter stroke (but bigger bore)
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The BMW 801F was delayed but scheduled for production in April 1945, BMW was forced to supply the BMW 801TS instead as an interim. It had promised the 801F or "similar" engine. Because the 801TS was lighter than the 801F and the Fw 190A9 had its centre of gravity built around the BMW 801F the Fw 190A9 had weights applied to the propeller to balance the aircraft. It got that close to production it effected the airframe.
The 2580hp was intended as a service rating. It wasn't a test stand experiment to detect vibration or heat load.
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BMW 801TH contains the 801F engine
BMW 801TS contains the 801S engine
BMW 801TQ contains the 801Q-2 engine = a D-2 with larger/better armored oil tank/cooler and provision for injection systems
The T designation is for "Triebwerksanlage", an engine complete will all parts to simply attach to an airframe using quick change mounts.
Never heard of the Fw 190 A-9 designed around/for the F-engine or requiring additional ballast at prop, this was an A-8 with a similar-weight but more-powerful engine. Later A-8 already got nose-heavier due to switching D-2 for slightly heavier Q-2 engine
I'd kindly ask for sources for the statements quoted.