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I'm not sure how to respond with your quotes in-line. Please accept my apologies.
Perhaps my fictional Mechanical Engine Fuel Control by monitoring cam position and other operating parameters would also be much better in controlling spark? The temperature sensors you mention (And pressure BTW.) as of 2020 are still analog and are not far removed their ancestors of 80 years ago. (I am aware of a few temperature switches and thermocouples that have been in continuous production for over 70 years. One of which is used on the F-35.) Admittedly the newer ones are now working in temps that would have boggled the engineers in the 1940's.
Agreed, like my little 2 liter, the engine would have to be boosted, I don't doubt it would have to be boosted to levels that would have been considered very high by 1940's standards. Again,a mechanical control that is monitoring exhaust temps, cylinder head temps,etc. would be far superior to a straight carbureted or even early fuel injected engine due to it's ability to monitor and control several parameters that were previously adjusted (Tuned if you will) and left alone until the engine required attention.
Please don't completely discount the availability of hydro-mechanical fuel controls that would have metered fuel far more accurately compared to a carburetor. GE had the first fuel controls and drawings in their hands in 1941 and by 1947 at least one company (Westinghouse) was developing "electronic" controls for their A/B's. Analog Engine "Electronic" Controllers (No transistors) as temperature limiters were in use at least as early as 1954 on the J65 in the FJ-4 that I am aware of, I wouldn't be surprised if they started showing up a bit earlier.
The technology for a mechanical engine control was on hand during WWII.
The T34 and the converted "hot rod" Apache in our Navy flying club both had Bendix mechanical pressure carbs, and they worked a treat. Bulletproof maintenance wise, economical on fuel, and seemingly immune to carb ice. Carb ice? In Key West, FL? Huh? You betcha! That's one of the little surprises that climate has for unsuspecting northcountry pilots who bring their planes down for a little fun in the sun. Continental powered 182s were the most frequent victims, along with the occasional older float carb Bonanza. Lycoming engines seemed to be less susceptible.I would note than many American engines (and a few British ?) used "pressure" carburetors which weren't really carburetors at all but single point throttle body fuel injectors. Not as good as multi point fuel injectors but better than some carburetors.
I have no idea how good or bad some of these carburetors were.
I will admit to not much practical knowledge in this area. However, the Chrysler aircraft engine developed late in WW II had 4 vales per cylinder with Hemi heads. I just read an article that stated they installed one of these in a P - 47 designated (P-47M) At sea level that huge Jug hit 504 MPH. I never have found any figures at altitude but it must have been impressive. This is only 20 MPH slower than The Dornier Arrow with two engines. Maybe if everyone did not jump into turbojets which at that time had only two advantages (speed and quiet) this magnificent engine could have been developed instead of shelved.
I would start with some smart but but not too radical ideas, because lets face it, they won't do too radical an idea. For example. Implement 4-valve heads and combustion chamber design on radial engines the way it should be done. As I understand it, the way the valves were laid out on the Bristol engines did not take full advantage of them the way they do today. My Harley M8 makes stupid power in comparison to my older but exactly the same CID twin cam and really, the only difference is that 4-valve head.
The Chrysler IV-2220 had 2 valves per cylinder, as did the Continental IV-1430 and Lycoming O-1230/H-2470. These were all based, at least loosely, on the Army "hyper" cylinder design.
Ain't 20/20 hindsight wonderful? Now if your chrystal ball were clear enough to recognize "ill conceived" while it's still only an idea, what a wonderful world that would be!I would suggest that most countries had too many engine development programs and that many of these were ill conceived.
I am sure a modern system (or even not so modern) could do a better job of controlling the spark. The question becomes at what cost? and how much improvement is needed if you don't change the operating range of the engine by very much? If the engine, once in the air, operates over a 2 to one speed ratio (1500rpm to 3,000rpm for instance) how important is variable ignition timing? Some engines did a get a crude form of ignition advance (useful for cruising?) and others were able to retard the timing for starting only. Many aircraft had trouble with ignition systems at altitude and had to resort to pressurizing the ignition system to prevent cross firing. I believe the Wright R-3350 in the B-29s resorted to a low tension ignition with coils for each plug? I could be wrong on that.
Look up the Chrysler 300 saga of the late 50s when they tried to use "electronic" fuel injection supplied by an aircraft company (Bendix) which turned into a fiasco, however well Bendix fuel management systems may have worked in an aircraft. reliability at car prices wasn't there.
I would note than many American engines (and a few British ?) used "pressure" carburetors which weren't really carburetors at all but single point throttle body fuel injectors. Not as good as multi point fuel injectors but better than some carburetors.
I have no idea how good or bad some of these carburetors were. But again, trying to compare a supercharged aircraft engine to a car ignores a few differences. The fuel, after going through the supercharger was better atomized than most cars with carburetors, In fact many early engines (late 20s) called the spinning impeller between the carb/s and the inlet pipes a "mixing fan" as it didn't provide much, if any boost and in a few engines ran at crankshaft speed, but then with 70 octane or under fuel you weren't gong to use much boost anyway.
P & W on the C series R-2800 didn't use a fixed jet to inject the fuel under pressure into the airstream but feed a "slinger ring" that went around the inlet of the supercharger with multiple openings that got a better fuel distribution than the fixed jet.
I would also note that RR got over 1800hp out a Merlin on a test stand in 1938 when they were working on the "Speed Spitfire" for a record attempt (not on gasoline) and I believe they managed 1600hp or better for 10 hours. It was this experience that helped convince them that the Merlin was capable of a lot of development without needing a lot of redesign.
RR also figured (in 1940 or just before) that give suitable fuels the potential power at sea level if the throttle could be fully opened of some of their engines were 1500hp (55.5hp per liter) at 2600rpm for the Melrin II and X. For the the Peregrine they were figuring 1365hp (64.6hp per liter) and 0.81hp per pound at 2850rpm. Both engines ran higher rpm in service but the throttles were not fully opened anywhere near sea level. This numbers were published in 1940, what was going on in secret?
I have no doubt that using modern knowledge and materials improvements could be made, It is just that the aircraft engines of the day were in a whole different catagory than even most race car engines of the day so the difference between modern car engines and those aircraft engines might not be anywhere near the difference that exists between modern car engines and racing car engines of the day.
I am sure a modern system (or even not so modern) could do a better job of controlling the spark. The question becomes at what cost? and how much improvement is needed if you don't change the operating range of the engine by very much? If the engine, once in the air, operates over a 2 to one speed ratio (1500rpm to 3,000rpm for instance) how important is variable ignition timing? Some engines did a get a crude form of ignition advance (useful for cruising?) and others were able to retard the timing for starting only. Many aircraft had trouble with ignition systems at altitude and had to resort to pressurizing the ignition system to prevent cross firing. I believe the Wright R-3350 in the B-29s resorted to a low tension ignition with coils for each plug? I could be wrong on that.
Look up the Chrysler 300 saga of the late 50s when they tried to use "electronic" fuel injection supplied by an aircraft company (Bendix) which turned into a fiasco, however well Bendix fuel management systems may have worked in an aircraft. reliability at car prices wasn't there.
I would note than many American engines (and a few British ?) used "pressure" carburetors which weren't really carburetors at all but single point throttle body fuel injectors. Not as good as multi point fuel injectors but better than some carburetors.
I have no idea how good or bad some of these carburetors were. But again, trying to compare a supercharged aircraft engine to a car ignores a few differences. The fuel, after going through the supercharger was better atomized than most cars with carburetors, In fact many early engines (late 20s) called the spinning impeller between the carb/s and the inlet pipes a "mixing fan" as it didn't provide much, if any boost and in a few engines ran at crankshaft speed, but then with 70 octane or under fuel you weren't gong to use much boost anyway.
P & W on the C series R-2800 didn't use a fixed jet to inject the fuel under pressure into the airstream but feed a "slinger ring" that went around the inlet of the supercharger with multiple openings that got a better fuel distribution than the fixed jet.
I would also note that RR got over 1800hp out a Merlin on a test stand in 1938 when they were working on the "Speed Spitfire" for a record attempt (not on gasoline) and I believe they managed 1600hp or better for 10 hours. It was this experience that helped convince them that the Merlin was capable of a lot of development without needing a lot of redesign.
RR also figured (in 1940 or just before) that give suitable fuels the potential power at sea level if the throttle could be fully opened of some of their engines were 1500hp (55.5hp per liter) at 2600rpm for the Melrin II and X. For the the Peregrine they were figuring 1365hp (64.6hp per liter) and 0.81hp per pound at 2850rpm. Both engines ran higher rpm in service but the throttles were not fully opened anywhere near sea level. This numbers were published in 1940, what was going on in secret?
I have no doubt that using modern knowledge and materials improvements could be made, It is just that the aircraft engines of the day were in a whole different catagory than even most race car engines of the day so the difference between modern car engines and those aircraft engines might not be anywhere near the difference that exists between modern car engines and racing car engines of the day.
Not with the manufacturer's recommendation or approval.BTW, I disagree that engines were not operated at WOT at sea level. (Take off,and low speed? agree 100%)
Not with the manufacturer's recommendation or approval.
An Allison with the 8.81 Supercharger gears could make just about 70in of MAP at sea level with no ram effect. take-off was usually at 44in. of MAP, hardly wide open.
In fact nearly every engine that was rated for WEP was using the extra supercharger capacity that existed because the engine was throttled back below it's FTH or critical altitude.
Take-off power was rarely (for later engines) done at WOT.
This is true for British and American engines, Other countries may differ.
In some cases for American engines you may see something like 1200hp at 48in for take-off at 2700rpm which can be held to 3,000ft. Which means the plane was allowed to use 48in at 2700rpm at an airfield 3000ft above sea level. At a sea level airport the plane was NOT allowed to use higher than 48in (officially) even though the supercharger would supply a bit more than 48in at sea level.
If you're going to go compression ignition, why not use the blown two stroke approach GM was developing about that time? In the '60s I drove busses powered with V6 and V8 versions of that. They spun at propeller speeds, produced gobs of torque, and were significantly lighter than comparable four strokes, despite the heavy Rootes blower on top, and didn't have the one-way lubrication system most two strokes had. They were good for three overhauls at 500K mile intervals and sold used at two million miles. I think a radial air cooled version of that with a centrifugal blower in the nose case in place of the unnecessary planetary reduction gear would have promise in Fantasyland. What say?Compression ignition two stroke radial with expansion chambers, turbo compounded. I think that expansion chambers on two strokes had significant possibilities in time travel fantasy land.
Reverse engineer the Hooker developed two-stage, intercooled mechanical supercharger from the Merlin/Packard merlins for the Allison V-1710. Reverse engineer the German fuel injection systems and single power lever systems for The V-1710 and P&W R-2800. Put the P-47 turbocharged R-2800 into both the F6F and F4U corsairs (with the German fuel injection technology and single power lever). Develop a short path turbocharged and intercooled system with fuel injection and single power lever for the P-38's V-1710. Less interdivisional Argument, less "not invented here" bullshit and more pooling of resources and more cooperation. Doesn't take any modern secrets to produce dramatically improved engines.
If you're going to go compression ignition, why not use the blown two stroke approach GM was developing about that time? In the '60s I drove busses powered with V6 and V8 versions of that. They spun at propeller speeds, produced gobs of torque, and were significantly lighter than comparable four strokes, despite the heavy Rootes blower on top, and didn't have the one-way lubrication system most two strokes had. They were good for three overhauls at 500K mile intervals and sold used at two million miles. I think a radial air cooled version of that with a centrifugal blower in the nose case in place of the unnecessary planetary reduction gear would have promise in Fantasyland. What say?
Cheers,
Wes
If you're going to go compression ignition, why not use the blown two stroke approach GM was developing about that time? In the '60s I drove busses powered with V6 and V8 versions of that. They spun at propeller speeds, produced gobs of torque, and were significantly lighter than comparable four strokes, despite the heavy Rootes blower on top, and didn't have the one-way lubrication system most two strokes had. They were good for three overhauls at 500K mile intervals and sold used at two million miles. I think a radial air cooled version of that with a centrifugal blower in the nose case in place of the unnecessary planetary reduction gear would have promise in Fantasyland. What say?
Cheers,
Wes