mdiehl
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Joined: 10/21/2000
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Okay, this has just gotten stupid as you have only proved that you are incapable of reading another persons post and that you don't even pay attention to what you have posted earlier.
That's precisely what I was thinking about you.
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You did not list 'dozens' of sources; you listed 2.
I said dozens exist.
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The first was a fairly amateur encyclopedia and the other was the Smithsonian which in general has used Gustin's work.
Right. David Donald is an "amateur." 
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My other "one" source that i have listed is the theater interagation documents from NARA. That is 200,000 or more pages right there. I was overwhelmed, but luckily they have a fairly good indexing system and it didn't take too long to find what i was looking for.
And it is indeed so obvious from your internet handle and extensive peer reviewed publishing record that I should take your word for this over the word of an editor and author of numerous books on aviation? I'll bite if I can look up your record of peer-revied publications on this matter. If you haven't established such a record, you've got some nerve calling someone else's work "amateur." If you have, you can convince me.
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On Octane.... Guess what, a Cessna 172 is not a high compression engine! I realize you will gain 2-6 Mph on a fighter plane using 100 octane... at least until the intakes clog with unburned fuel and your plane starts to backfire! You have to be about 12 and you read lots of articles on the internet so you think you know something about engineering. Well guess what? You don't!
That was rather non-sequitur. Again, you're the one who brought the Cessna into this, and you're the one who says it runs poorly on 87 octane. A claim I won't dispute. What you have not demonstrated is any real knowledge of how octane affects engine performance. The reason why high octane does not (much) impair the efficiency of an engine designed for low octane is that the primary cause of reduced efficiency in that particular circumstance is trace quantities of uncombusted fuel. That does not produce knock, it just produces and inefficent use of fuel. If you put 87 octane, however, in an engined designed for higher octane, you get knock because of premature combustion. Getting back to your orginal assertion, it does not follow that putting 100 octane (or even 103) in an engine designed for, say, 93 octane, is necessarily going to reduce performance by much. I heard it said that if you put 100 Octane in an automobile (Sunoco used to sell 100 Octane, which I used to put in my Saab many years ago because it was designed for leaded gas), you can lose fuel economy by up to 3%. I am not sure how that translates into lost RPMs, but assuming a 1:1 correlation, and a/c capable of, say, 420 mph designed for, say, 87 octane (no such aircraft engine was ever made) might in theory be capable of 3% greater speed... say 432.6 mph. But I don't know, maybe someone with a little more information and a little less bluster than yourself can speak to the issue.
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I have never at any point said the Japanese did not gain their horsepower from greater compression... However, the Japanese did not make their engines with a compression of a Pratt & Whitney because they did not have the fuel to burn in it and premature explosion tends to be bad for the engine.
We're getting somewhere at least. Given that you seem to agree that greater compression is the way that they achieved greater output, does it not now follow that using a higher octane fuel is less likely to cause premature explosions? If so, does it not then follow that putting 100 or even 103 Octane in the engine would not have adversely affected the Ki-84 test aircraft's engine because of knocking (premature detonation) as you originally suggested? Or did you not mean to suggest that? Seems to me that you implied that putting good US fuel in the engine would cause knock, resulting in a test aircraft that underperforms vis a vis the operational one? If you did not mean to imply that my bad, then, (but I'll bet I'm not the only one who read your post who was confused by your language).
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Oh, yeah, the Americans were always outnumbered! eek! there are thousands of them! yikes! Thats an old story. You may have noticed that i said 'starting in late 1942'. Oh, but you don't bother to read anyones posts.
I do not agree that the Americans had a numerical advantage starting in late 1942. If you can make a good case for it I'm willing to hear you out. I guess we're primarily talking about the Solomons, New Guinea and, err, AVG for primary sources of air combat data.
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'If you slow down you lose' No, that is your & the American airforce's assumption. That is not my assumption. I have already said that i agree that speed is the most important thing; it however is not the only thing and i have mentioned an occasion when another airforce showed that speed could be a disadvantage as the British F2's turned inside the Americans, evaded their missles and then 'shot' them down.
No problem. All I wonder is why the F16s in the mock engagement were not presumed to shoot at the F2s with their 30mm? If you only allow missiles, and if in MODERN WARFARE (which I specifically stipulated is different from the gun-only combat of WW2.. ;eaving aside a few trivial things like 5" rockets fired at B17s) aircraft can fox a missile by turning, then the missile-only armed aircraft is at a disadvantage. The US learned as much IIRC during the early stages of the Viet Nam war. Again, IIRC, there were some missile-only armed US a/c that foud themselves needing guns.
In WW2, however, you don't have missiles. There's some ability to evade by turning, but an aircraft approaching you with superior speed will tend simply to break off and come around for another high speed pass, unless (and only if) you are talking about the interval from, say, 8 December 1941 through March 1942 in the New Guinea area. In those circumstances the primary problem was that P-40s did not use "boom and zoom" and so found themselves in energy-burning turning engagements that, with sufficient time, gave Japanese a/c an edge. If your down to 220 mph IAS in a P-40 the Zeke can out-turn and out-accelerate you (so you can't just run away).
But that would NOT be the circumstances of employment in general for any late war Japanese or American a/c. in general, now, would it.
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Mike: No, that is not a weird comment! You answered your own question if you could bother to think it through! The airforces without 100 octane fuel available limited the compression on their engines to avoid exactly what you have just said!
Um, HOW, exactly, do you imagine that the Ha-21-25 series developed 1900 HP without using higher compression? IIRC, the Japanese effective late war octane for SOME fuels produced via hydrogenation was something like 93-97 octane, but there were problems with quantitityand purity. Are you claiming that the Ha-21 was operating at the same compression ratios as, say, the engine in the A6M2?
More to the point, a Ki-84 pushing 390 mph is not going to suddenly just shed 90 mph to get into a flight profile where it can out-turn a P-51 going 390 mph. In the time it takes the Ki-84 to slow down enough to establish roll and turn characteristics that will allow the Ki-84 driver to lead the P-51 and shoot it down, the P-51, if properly flown, will be LONG GONE. It will literally be a mile or more away. THAT IS WHY THE FASTER AIRPLANE CONTROLS THE FIGHT. And that is why the entire post-ww2 history of a/c development drove fighters to greater speeds up to what amounts to the current practical limit of a/c speed in combat. IIRC that's somewhere around Mach 2. Since missiles can go quite a bit faster than almost everything (leaving aside the SR-71 for example), we now have, unlike WW2, circumstances in which maneuverability really does increase the survivability of an a/c.
Of course, if someone comes up with a missile that can outmaneuver a/c then we'll be back to trying to solve the problem with increase airspeed or perhaps shooting the missiles down.
< Message edited by mdiehl -- 6/11/2004 8:33:29 PM >
_____________________________
Show me a fellow who rejects statistical analysis a priori and I'll show you a fellow who has no knowledge of statistics.
Didn't we have this conversation already?
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