Matrix Games

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Waiting for it ................

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ORIGINAL: JohnDillworth

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Waiting for it ................

OK, what did I do? I didn't cross Terminus did I? Which old timer? Did I compare specific aircraft? I swear I only meant to illustrate my question.....Oh great....There is a knock at the door.....hold on .......Who the hell is WITPAE Black Ops? Helppppppppppppppppp.................

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ORIGINAL: vettim89

Waiting for it ................

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ORIGINAL: Historiker

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ORIGINAL: vettim89

Waiting for it ................

I really don't have any intention to insult you and am really sorry, but isn't this almost trolling itself?
It annoys me every time, when those wise guys go into threads and don't contribute anything but "the trolls will come".

I know, calling someone a troll is one of the most harsh insults you can say in a forum, but again: Isn't that trolling by itself?

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ORIGINAL: Alfred

You know, those Americans were very gamey. The high octane was just one of several gamey actions which borked the war against the Axis. I'm often reminded about how most armchair generals just criticise the Italians for standardising with 840 hp FIAT engines for their airplanes without taking into account the real world constraints on their design options. Same issues often applied to the Japanese, which issues are never fully taken into account (in fact usually not at all) by people who argue how Japanese industry could have been reshaped to make better war materiel.

Alfred

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Looks like no one is gonna answer your question Mr Dillworth. Too bad. It was a good one.

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ORIGINAL: vettim89

Waiting for it ................

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ORIGINAL: PaxMondo

Bill's answer is about as good as you can get without going into some pretty deep science. 

This is all off the top of my head, so apologize for any inconsistencies.  Octane numbers are a bit arcane.  First off it is a scale, it doesn't relate to reality.  100 Octane meant 100% N-Octane back in 1910 or so, so going over a 100 is kinda hard to understand.  It is all about anti-knock.   Then there are two ways to calculate this, research and motor (RON and MON).  The europeans and americans use a differently weighted average of the two to establish their scale.  Then, and even more importantly, is that how octane was boosted in the 40's isn't how it is done today.  Then it was about alkylation and so the octane boost was coming from n-nonane and n-decane type fuels.  Now, it comes from FCC and that gives you alkylenes like benzene and toluene to boost the fuel.  The amounts required to boost are different and how the impact cylinder temps are different.  They also behave quite differently under temperature and pressure as their partial pressure are different.

But a lot of this isn't as important as it seems.  Once you bring methanol/water injection into play octane become less of a factor.  Still a factor, yes, but less than you think.  Let's look at the chemistry and the mechanics here.  Engines are all about gas expansion forcing a piston to move down a cylinder and turn a crankshaft.  Igniting gas is good for about a 38x factor of expansion, not counting temperature effects.  That's awful good.  Water though is good for 18x.  The nice thing about water is that it take heat to move to steam, and this is how water injection works.  You start with an engine that is running too hot, you inject water to cool it and you actually get MORE power from it as the water expands into steam.  This works really well with radial air cooled cylinders as they are all more or less the same.  With in line water engines, you always struggle to get in inside cylinders as opposed the outside (on a V8 this would be 2,3,6,7 against 1,4,5,8) to be the same temperature.  The downside to water is that it is incredibly corrosive and impurities are very dangerous to metals (like chlorine and sodium as in salt).  Now add on superchargers and/or turbochargers (twinchargers) and again you get more complex.  On top of all of this is that in the 40's all they had was analog controllers. 

By wars' end the germans (extensively) and the IJ (Dinah and some other models) were using water/methanol.  This, when coupled with charging systems, mitigates the octane issue.

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ORIGINAL: witpqs

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ORIGINAL: PaxMondo

Bill's answer is about as good as you can get without going into some pretty deep science. 

This is all off the top of my head, so apologize for any inconsistencies.  Octane numbers are a bit arcane.  First off it is a scale, it doesn't relate to reality.  100 Octane meant 100% N-Octane back in 1910 or so, so going over a 100 is kinda hard to understand.  It is all about anti-knock.   Then there are two ways to calculate this, research and motor (RON and MON).  The europeans and americans use a differently weighted average of the two to establish their scale.  Then, and even more importantly, is that how octane was boosted in the 40's isn't how it is done today.  Then it was about alkylation and so the octane boost was coming from n-nonane and n-decane type fuels.  Now, it comes from FCC and that gives you alkylenes like benzene and toluene to boost the fuel.  The amounts required to boost are different and how the impact cylinder temps are different.  They also behave quite differently under temperature and pressure as their partial pressure are different.

But a lot of this isn't as important as it seems.  Once you bring methanol/water injection into play octane become less of a factor.  Still a factor, yes, but less than you think.  Let's look at the chemistry and the mechanics here.  Engines are all about gas expansion forcing a piston to move down a cylinder and turn a crankshaft.  Igniting gas is good for about a 38x factor of expansion, not counting temperature effects.  That's awful good.  Water though is good for 18x.  The nice thing about water is that it take heat to move to steam, and this is how water injection works.  You start with an engine that is running too hot, you inject water to cool it and you actually get MORE power from it as the water expands into steam.  This works really well with radial air cooled cylinders as they are all more or less the same.  With in line water engines, you always struggle to get in inside cylinders as opposed the outside (on a V8 this would be 2,3,6,7 against 1,4,5,8) to be the same temperature.  The downside to water is that it is incredibly corrosive and impurities are very dangerous to metals (like chlorine and sodium as in salt).  Now add on superchargers and/or turbochargers (twinchargers) and again you get more complex.  On top of all of this is that in the 40's all they had was analog controllers. 

By wars' end the germans (extensively) and the IJ (Dinah and some other models) were using water/methanol.  This, when coupled with charging systems, mitigates the octane issue.

When you say water/methanol, do you mean that the entire fuel was water/methanol, or that water/methanol was added to the avgas?

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They tested the "V-Power" 100 Octane fuel in sport cars to find out whether the significantly higher price is justified. Their finding was, that in modern car engines - of course - the increase in performance is neglible.

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ORIGINAL: PaxMondo

Bill's answer is about as good as you can get without going into some pretty deep science. 

This is all off the top of my head, so apologize for any inconsistencies.  Octane numbers are a bit arcane.  First off it is a scale, it doesn't relate to reality.  100 Octane meant 100% N-Octane back in 1910 or so, so going over a 100 is kinda hard to understand.  It is all about anti-knock.   Then there are two ways to calculate this, research and motor (RON and MON).  The europeans and americans use a differently weighted average of the two to establish their scale.  Then, and even more importantly, is that how octane was boosted in the 40's isn't how it is done today.  Then it was about alkylation and so the octane boost was coming from n-nonane and n-decane type fuels.  Now, it comes from FCC and that gives you alkylenes like benzene and toluene to boost the fuel.  The amounts required to boost are different and how the impact cylinder temps are different.  They also behave quite differently under temperature and pressure as their partial pressure are different.

But a lot of this isn't as important as it seems.  Once you bring methanol/water injection into play octane become less of a factor.  Still a factor, yes, but less than you think.  Let's look at the chemistry and the mechanics here.  Engines are all about gas expansion forcing a piston to move down a cylinder and turn a crankshaft.  Igniting gas is good for about a 38x factor of expansion, not counting temperature effects.  That's awful good.  Water though is good for 18x.  The nice thing about water is that it take heat to move to steam, and this is how water injection works.  You start with an engine that is running too hot, you inject water to cool it and you actually get MORE power from it as the water expands into steam.  This works really well with radial air cooled cylinders as they are all more or less the same.  With in line water engines, you always struggle to get in inside cylinders as opposed the outside (on a V8 this would be 2,3,6,7 against 1,4,5,8) to be the same temperature.  The downside to water is that it is incredibly corrosive and impurities are very dangerous to metals (like chlorine and sodium as in salt).  Now add on superchargers and/or turbochargers (twinchargers) and again you get more complex.  On top of all of this is that in the 40's all they had was analog controllers. 

By wars' end the germans (extensively) and the IJ (Dinah and some other models) were using water/methanol.  This, when coupled with charging systems, mitigates the octane issue.

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Allies probably had better qualty in this as well but I am just speculating.

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ORIGINAL: JohnDillworth

It goes to maintenance in general. The US was just better at providing the support and structure for maintaining complex machines. I've read that the US had a ton of kids that were used to tinkering with farm machinery when they were called up. Internal combustion engines were not unusual for them so the transition into a more complex engine maintenance was not that far of a leap. It was probably true for all engineering disciplines from aircraft mechanic to SeaBee. Education was highly regarded at the time and not at the expense of blue collar skills. This may have also been true in Germany, Australia and England but perhaps not so much in Japan. No doubt Japan had some excellent mechanics with the very best being on the CV's that were the equal of the Allies, after that it may have dropped off. Combine that with a disrupted supply chain, inter-service stupidity, sometimes poor fuel, some malnutrition and a fundamental disregard for human lives and you have an increasingly separate situation

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ORIGINAL: Gridley380

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ORIGINAL: JohnDillworth

It goes to maintenance in general. The US was just better at providing the support and structure for maintaining complex machines. I've read that the US had a ton of kids that were used to tinkering with farm machinery when they were called up. Internal combustion engines were not unusual for them so the transition into a more complex engine maintenance was not that far of a leap. It was probably true for all engineering disciplines from aircraft mechanic to SeaBee. Education was highly regarded at the time and not at the expense of blue collar skills. This may have also been true in Germany, Australia and England but perhaps not so much in Japan. No doubt Japan had some excellent mechanics with the very best being on the CV's that were the equal of the Allies, after that it may have dropped off. Combine that with a disrupted supply chain, inter-service stupidity, sometimes poor fuel, some malnutrition and a fundamental disregard for human lives and you have an increasingly separate situation

All true. The Japanese were able to mitigate this early on by providing lavish training for a very small force. When they tried to rapidly expand their quality dropped sharply.

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ORIGINAL: JohnDillworth

Does anyone know the average octane ratings that were available to the Allies and Japan?

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This is from Aircraft in Profile #240 "Aichi D3A ('Val') & Yokosuka D4Y ('Judy') Carrier Bombers of the IJNAF (M. C. Richards and Donald S. Smith):
Fuel Capacity of D3A
"Internal 1,079 liters (235 Imperial gallons) in five unprotected tanks; two in each wing, one under pilot's seat, all containing 92 octane petrol. In starboard wing root, a small fuel tank (100 octane) for take of; 58 liter (25.8 Imperial gal.). One 60 liter (13.2 Imp.gal.) oil tank behind the engine."