109 e3b against spitfire II

[Crumpp]

there is no source that states that this is incorrect,

Yes there is a primary source that refutes the secondary source you posted, Seadog.

The seventh conference on 18 May 1940 clearly states that certain units in Fighter Command will make the switch.

That document has been posted ad nauseum.

As this on going fuel debate....

The best source on German Aviation Fuels is the Fischer Tropsch Archives.

http://www.fischer-tropsch.org/

They have a good collection of documents online anyone can learn about German fuels. Allied Fuel and German fuels were not directly comparable.

B4 is slightly better than 87 grade Allied fuels and is roughly equal to 91/~115 octane.

C3 began as the equivalent to 100/130 grade allied fuels and was later improved to 100/140 grade which allowed such improvements as a straight manifold pressure increase without additional knock limiting performance enhancement to 1.62ata in the BMW801D2 series and 1.98ata in the DB605 series engines.

C3 was adopted in 1940 and was used during the BoB.



The whole debate is silly and pointless. The arguments are put forth by gamers to make their personal game play more enjoyable such that a game shape performance can overcome their own inadequacies. It is an agenda advanced by clowns who focus on whatever specific portion paints the desired picture without regard to the whole.

The facts are the German fuel was roughly equal but on the whole slightly inferior to the natural petroleum. The Allied fuels were better but allied engine technology could not take full advantage of their superior fuels. The German materials technology, chemical engineering, and fuel metering technology was much better and made up for the lower quality fuels.

Just the fact the Germans had direct fuel injection technology and the allies never did balances any fuel differences. One can make considerable power gains without changing fuel type just by changing the fuel metering system from a carburetor or Throttle Body Injection to Direct Injection. In a 1000 hp engine, you can expect to gain 80-150 hp just by changing the fuel metering method.

The whole debate ends up being a wash.

[Seadog]

Originally Posted by Crumpp

Yes there is a primary source that refutes the secondary source you posted, Seadog.

The seventh conference on 18 May 1940 clearly states that certain units in Fighter Command will make the switch.

and the accepted dates for the BofB are July 10 to Oct 30, 1940.

[Crumpp]

Seadog,

18 May 1940 is only 6 weeks from the start of the Battle of Britain.

The language in that primary source document refers to "certain units" and not "ALL" units.

Very importance difference.

[Seadog]

Originally Posted by Crumpp

Seadog,

18 May 1940 is only 6 weeks from the start of the Battle of Britain.

The language in that primary source document refers to "certain units" and not "ALL" units.

Very importance difference.

The German Army defeated France in 6 weeks...6 weeks is a long time.

RAFFC had many units which did not require 100 octane, such as OTU and a few squadrons of Gladiators. In any event, again all the evidence points to RAFFC operational Merlin engined squadrons using 100% 100 octane. There isn't a single source that states that an operational Merlin engined fighter squadron was using anything else.

[Blackdog_kt]

Originally Posted by Seadog

Asking for more power is exactly the same as asking for higher octane fuel. ( I didn't have to wait long for the "we don't need no stinking 100 octane fuel" claims from the Lufters... )

No it's not. An engine of a sufficiently bigger displacement running "normal" fuel with the appropriate boost values will still outperform an engine with a lower displacement. If they have similar displacement a smaller engine running 100 octane could reach or even surpass the HP of a bigger one running 87 octane, but a sufficiently bigger displacement would ensure superior performance even when running fuel of a lesser octane rating.

And that's without even taking into account other things like supercharger design and gearing and propeller design, things which affect not only the powerband of the engine but also the appropriate altitudes where the extra power can be better used.

What i'm trying to say is that asking for engines with more HP can mean a combination of many different things. When you are discounting them all and pretend its only the octane rating that matters you are just simplifying for the sake of pushing a personal viewpoint without having to come up with the supporting proof: "they asked for more power, so they should surely mean a better octane rating".

I'm all for Spits and Hurricanes getting their 100 octane and constant speed prop variants. Keep the current ones for battle of France scenarios (i mean we already have much of the map so why lose the ability to create such missions) and let's also add the proper battle of Britain variants.

I'm also in favor of having a 50% chance (or whatever the appropriate percentage was) of spawning with DB601N engines on your 110, which you make absolutely no mention off in any of your arguments. I've given you the benefit of doubt until now but you're gradually exhausting that reserve.

No offence meant and i'm not saying you're just pushing for a gameplay advantage for your favorite ride because i'm not the kind of fool that will pretend to know what's in another person's mind. What i'm saying is that you sure sound like that more and more as time goes by, i just don't have a way to confirm it, which makes me averse to getting convinced out of a matter of principle. I guess this goes for many others as well.

[Seadog]

Originally Posted by Blackdog_kt

1)What i'm trying to say is that asking for engines with more HP can mean a combination of many different things. When you are discounting them all and pretend its only the octane rating that matters you are just simplifying for the sake of pushing a personal viewpoint without having to come up with the supporting proof: "they asked for more power, so they should surely mean a better octane rating".

I'm all for Spits and Hurricanes getting their 100 octane and constant speed prop variants. Keep the current ones for battle of France scenarios (i mean we already have much of the map so why lose the ability to create such missions) and let's also add the proper battle of Britain variants.

2)I'm also in favor of having a 50% chance (or whatever the appropriate percentage was) of spawning with DB601N engines on your 110, which you make absolutely no mention off in any of your arguments. I've given you the benefit of doubt until now but you're gradually exhausting that reserve.

3)No offence meant and i'm not saying you're just pushing for a gameplay advantage for your favorite ride because i'm not the kind of fool that will pretend to know what's in another person's mind. What i'm saying is that you sure sound like that more and more as time goes by, i just don't have a way to confirm it, which makes me averse to getting convinced out of a matter of principle. I guess this goes for many others as well.

1) Again, pilots wanted more power. In the Merlin III, 30% more power was available through a simple mod, that could be done in an afternoon using fuel that was readily available. RAF pilots had been aware of this for several years, and they got a full transition to 100 octane prior to the BofB, indeed many France based Hurricane squadrons used it during the BofF. I don't and haven't discounted other options, but raising displacement, for example, invariably means greater weight and greater frontal area, something that pilots don't want.

2) see my post #71:
http://forum.1cpublishing.eu/showpos...1&postcount=71
By all means, include all historical engine and aircraft variants.

3) No, I am pushing for a game that sims RL. In RL Merlin III aircraft have access to much higher power at low altitude. At high altitude these advantages dwindle and the Me109 has many advantages, and this will force the Me109 pilots to fly as per RL, IE, stay high, and fight in the vertical. Dogfighting Hurricanes at low altitude is not a great idea. The RAFFC made a rapid transition to 100 octane engines and CS props and it was a much tougher proposition than the Luftwaffe had been led to believe, but thats how it was.

[Kurfürst]

Originally Posted by Seadog

I don't and haven't discounted other options, but raising displacement, for example, invariably means greater weight and greater frontal area, something that pilots don't want.

Compared to that theory, German DB 601 was same size as weight as single stage Merlin, 605 actually lighter then two staged Merlin, while the French 35-liter class Hispano Suize V12s were considerably lighter than both.

The only practical way a smaller displacement engine can keep up with larger ones is by heavy supercharging, but that does not comes free, superchargers and their systems add weight, and so does decreasing fuel effiency: more fuel need to be carried for same range.

[Viper2000]

Originally Posted by Crumpp

Just the fact the Germans had direct fuel injection technology and the allies never did balances any fuel differences. One can make considerable power gains without changing fuel type just by changing the fuel metering system from a carburetor or Throttle Body Injection to Direct Injection. In a 1000 hp engine, you can expect to gain 80-150 hp just by changing the fuel metering method.

The whole debate ends up being a wash.

Direct injection isn't necessarily the best approach.

If you're supercharging then putting fuel into the flow upstream of the supercharger will cool the flow by about 25 K due to the latent heat of evaporation of the fuel.

This considerably reduces the compression work required from the supercharger, which is equivalent to an increase in its polytropic efficiency.

I would suggest that the mixture distribution is likely to be pretty good downstream of the supercharger under design conditions, because the fuel is completely evaporated.

Direct injection will obviously achieve better mixture distribution at low rpm where the supercharger delta H isn't sufficient to guarantee that all of the fuel is evaporated. So DI will give you better performance close to idle. This is very important for car engines, but not so much for aeroplanes.

Furthermore, as you develop your engine and increase the amount of supercharge, you'll tend to cruise higher. Even at constant boost, you'll see a higher supercharger delta H and higher charge temperature, which makes the advantage of adding fuel upstream of the supercharger more important.

It's also much easier and cheaper to make and maintain a single point fuel injection system (be it via a pump or a carb) than it is to make individual injectors for each cylinder.

http://www.flightglobal.com/pdfarchi...0-%200562.html
http://www.flightglobal.com/pdfarchi...0-%200563.html
http://www.flightglobal.com/pdfarchi...0-%200569.html

If direct injection really was so great for piston aero-engines, the chances are that the Allies would have adopted it immediately post-war when all Axis technology was theirs for the taking. The fact that they didn't do so speaks volumes.

See also:
http://www.wwiiaircraftperformance.o...in-lovesey.pdf
(The chronology of engine ratings and outputs may also be of general interest; presumably Mr. Lovesey counts as a primary source...)

[CaptainDoggles]

If direct injection really was so great for piston aero-engines, the chances are that the Allies would have adopted it immediately post-war when all Axis technology was theirs for the taking. The fact that they didn't do so speaks volumes.

But engine design was heading towards turboprops in those years (and obviously turbojets), what with the "trent-meteor" hybrid that was instrumental in the development of Rolls-Royce's Dart engines.

[Crumpp]

2009 Technology of the Year: Direct Fuel Injection

Direct injection-squirting pressurized fuel straight into each cylinder-is the key to keeping internal-combustion engines relevant in the future. For enabling a major step forward in gas and diesel engine power, efficiency, and cleanliness, direct fuel injection is AUTOMOBILE MAGAZINE's 2009 Technology of the Year.

While injecting fuel into the combustion chamber requires approximately fifty times the pressure used with port injection and additional electronic control sophistication, significant benefits are delivered. Since no fuel is deposited on intake-port walls, the air/fuel mixture can be more precisely maintained, benefitting both mileage and emissions. In addition, the cooling effect of gasoline droplets changing to vapor inside the combustion chamber facilitates a higher compression ratio without incurring detonation. Squeezing the mixture harder during compression and allowing it to expand longer on the power stroke wrings additional power out of every ounce of gasoline.

http://www.automobilemag.com/feature...ion/index.html

Single point injection has no advantages over direct fuel injection at all. The Supercharger is on a completely separate circuit and the engine still receives all the benefits of supercharging with the additional benefits of direct injection.