There seem to be a number of misunderstandings of this document, which only covers German fuels to 1943.
First of all consider that on page 8 that samples of German green dyed fuel (usually C3) is given as having an average RON/PN of 95/110 over 1942 (well down on the 100/130 that had taken over from 100 octane in allied service by then). Samples 285,305,311, 317,318-321 327, 328/9 256 had ratings of 97.5/118.5, 96.4/125,93.6/124, 95/125,95/125,95/125 respectively.
It is noted by British intelligence that the Germans didn't have an engine to take advantage of this improved rating of 96/125 that was achieved in 1943 but that the potentialities should be kept in mind. Of course that engine was the late 1943 BMW801 with increased boost (1.65ata and 1900hp) and with C3 einspriztung (1.65ata and 2050hp). The C3 rich mixture injection was never detected by allied intelligence.
Now in terms of the tests of samples AIR 336 and AIR 342 and their "120% of 100/130 rating". There were two tests for fuels with rich mixture RON ratings greater than the 100 of the iso-octane referenced RON test.
There was the well known performance number or PN test where the rich fuel was supercharged into the test stand engine to the point just below at which knocking occurred at which point a torque meter would measure the increased power attainable.
The other method was the
3C mixture rating which refers to
AFD-3C standard, not to be confused with Luftwaffe
C3 fuel. In this method iso-octane was used as a standard and the amount of TEL tetra-ethyl lead added to make it perform as the rich mixture under test was used as a reference standard. I read this as saying that the German fuel had 20% more lead.
The Germans simply had inferior quantities and qualities of duel available to them.
Higher PN fuels helped at lower altitudes, not at the altitudes where the XIV excelled.
Intercooling may have been heavier than simple ADI, but it never ran out. The performance afforded by intercooling was accessible at all times during a flight.
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I believe that the Mk 108 was a poor air to air weapon. While the round was heavier, it's muzzle velocity was only ~60% of the Hispano's. The Mk 103 was the great 30mm hope of the Luftwaffe, but it wasn't really sorted before the end of the war.
The use of 100/130 fuel surely allowed the Merlin and Griffon base set up, ie compression ratio and supercharger settings, to be optimally configured for standard use of 100 octane fuel as opposed to 87 octane and so indirectly improved its power at altitude, when 110/150 came along the engine was already preconfigured for a higher octane fuel.
The DB605L, with the two stage supercharger, seemed to require the higher octane C3 fuel. This is because pre-ignition is heavily a function of temperature which is a function of pressure ratio and compression ratio rather than manifold pressure and a two stage supercharger is likely to be producing pressure ratios of 5:1 at 10,000m and a rather larger temperature increase. Even an intercooler can't pull out all the heat.
Had the Daimler Benz DB605 series had a fuel as good as 100 octane fuel available the DB605 would have been mass produced in the variants with a higher compression ratio (8.4:1 rather than 7.4:1) This would increase power with no increase in fuel consumption and with no decrease in Full Throttle Height.
The introduction of the intercooler on the Merlin 61 added about 120kg to the 620kg Merlin 20 series. A 2000hp engine consuming fuel at an rich setting and sfc of 0.55 will use about 1100lbs (500kg or 500L) and hour. MW-50 would be added at about the same rate as the fuel so an 86L tank i.e. 190lbs would add about 10-12 minutes of WEP available. It seems enough given the other time limits on the engine.
The Mk103 was adequate to ranges equal to half its muzzle velocity, say 240 meters. It would be uncommon for greater ranges to be experienced and even with a higher velocity issues of the size of the target within the reticule become and issue.
Or DB gets really smart, lowers down the compression ratio of the DB 605, so it can do eye-watering 2.5 ata.
.
Not really that smart. Lets drop the pressure ratio of the 87 octane DB605A from 7.5 down to the same level as the Allison/Merlin ie around 6:5 (the merlin was even less) we've now lost about 13.33% of our expansion stroke and almost as much power while still burning the same amount of fuel. We can now increases the compression ratio of the supercharger but as this now forces more air and fuel into the engine and means that we must deal with much more waste heat and higher fuel consumption. The extra waste heat requires larger radiators and possibly higher coolant flows. The supercharger is now being used to over boost the engine and can no longer provide altitude compensation. We need a larger or a two stage supercharger. The heat increase at some point compels us to consider and intercooler. Our weight has gone up.
Would it be reall woth it? could the little Me 109 frame cope with larger radiators and provide the space for an intercooler.
However, simply provide 100/130 fuel to the Me 109, increase the compression ratio with higher crowns on the pistons and it seems a win win: no decrease in full throttle height, more power with no increase in fuel consumption or thermal load. We only need to make sure the bearings can take the extra power.
