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Jet fighter top speed at military power
I am wonderning what the top speed (in mph) a clean F-15C, Mirage
2000, F-16C, and MiG-29 could accelerate to in level flight at optimum altitude (not just sea level) without afterburner. I usually see the top clean speed and the top sea level speed (with afternburner?) quoted, but rarely the top military power speed. If there are any online references for non-afterburner speeds of other supersonic jets, I'd be interested to know where to find them! Secondary question: did the F-15 get faster recently? Reference books of a decade or so ago tended to quote 1650 mph as top speed in clean configuration ion a good day (etc.) but now I see figures of 1875 mph on USAF web sites. Any help would be appreciated. |
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#3
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"David L. Pulver" wrote in message om... I am wonderning what the top speed (in mph) a clean F-15C, Mirage 2000, F-16C, and MiG-29 could accelerate to in level flight at optimum altitude (not just sea level) without afterburner. I usually see the top clean speed and the top sea level speed (with afternburner?) quoted, but rarely the top military power speed. If there are any online references for non-afterburner speeds of other supersonic jets, I'd be interested to know where to find them! Clean F-15C, F-15E, F-16s with -220, -229 engines can hold .98 to .99 Mach in Mil power.. |
#4
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On Thu, 27 Nov 2003 16:04:29 GMT, Ed Rasimus wrote:
You would probably need to have the -1-1 charts to get a number. Since you specify "optimum altitude" the number wouldn't give you a comparison between aircraft. My suspicion (and it has little more going for it than that) is that with modern engines and low-drag shapes, the number will be pretty close to .95 mach for each. That wouldn't surprise me at all. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: , but first subtract 275 and reverse the last two letters). |
#5
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Don't know about the new stuff but an F104A with the J79-19 engine was
good for .97M at sea level and would accelerate to 1.05M in honest to God level flight at 25,000, all in military power (non-AB). Did it myself. Walt BJ |
#6
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The F-15C has better engines than the
F-15A. Maybe that is the cause for the discrepancy. I think its like this: A- 25,000 lbs each C,E- 29,000 lbs each Nope. Only some of the E's have the IPE (PW-229). The remainder as well as all the A's through D's have PW-220s or PW-220Es (except for the C/D's at Langley, Eglin, and Tyndall, and several A/B ANG units that still use the old PW-100s). During flight test the clean E with PW-229s easily cruised above M 1.0 at mil, whether accelerating up to it or decelerating down to it. It is not likely the fully loaded E can do this. |
#7
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During flight test the clean E with PW-229s easily cruised above M 1.0 at mil, whether accelerating up to it or decelerating down to it. It is not likely the fully loaded E can do this. By clean, do you mean w/o conformal tanks? By easily cruised, do you mean accelerated through mach w/o resorting to A/B? Is this based on personal experience? I have little doubt the clean F-15E can sustain 1.2 give-or-take in mil ... but the acceleration through transonic might be a problem. By the same token, the F-14B/D's can also supercruise, but they need A/B to get there first. The difficulty is handling the transonic drag rise, largely a function of the design drag characteristics of the jet. Low aspect ratio, area-ruled, thin-winged aircraft tend to do best (think F-104, Mig-23). Drag rises sharply starting around .92 or so and peaks around 1.1-1.2. Most aircraft run into a wall here (particularly at military thrust) and the difference in speeds attained is remarkably little (I found the F-8 to be a wee bit faster in military than the F-4, but I never flew the older and cleaner Phantoms .... the F-4H1 was reputedly good for 1.04 or so, similar to F-104). And recent designs have generally abandoned minimum-drag configurations to attain other, more useful, characteristics. A/C top speeds are illusory ... sometimes I think they're based more on what comes from marketing than engineering. The F-14 was attributed with 2.34 (it attained 2.41 ONCE in flight test and was artificially limited to 1.88 in the fleet ... though it got there easily enough). The F-18 has a 1.8 claim ... I know NO ONE who's seen close to that (so maybe once in flight test?). The F-15 is always attributed with 2.5/1650mph ... again maybe once in flight test? (The PsubS curves I've seen would suggest otherwise, and perhaps nobody told them about what happens to plexiglas at those speeds.) Of course when you hang some ordnance, drag goes up and speed goes down ... sometimes dramatically. If one restricts the argument to military thrust only, top speed ranges from ..92 or so (low thrust or high drag limited) to maybe 1.04. Not much of a difference if you're trying to outrun an AIM-120. R / John |
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Thanks for the responses!
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#9
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A/C top speeds are illusory ... sometimes I think they're based more on what comes from marketing than engineering. The F-14 was attributed with 2.34 (it attained 2.41 ONCE in flight test and was artificially limited to 1.88 in the fleet ... though it got there easily enough). The F-18 has a 1.8 claim ... I know NO ONE who's seen close to that (so maybe once in flight test?). Sometimes I wonder if the marketing guys just go something like "well it's got a thrust to weight of X, it's got them there fixed intakes so it's automatically less than two, and it's not quite as streamlined as an F-16, let's slap '1.8' on it and call it good". Any 4th generation aircraft with fixed intakes is automatically assigned 2 or less and if it's got variable intakes they'll give it a 2.2 or a 2.35. Those seem to be the magic criteria but I doubt they're based on anything but numbers pulled out of somebody's backside. |
#10
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On Sun, 30 Nov 2003 03:13:36 GMT, Scott Ferrin
wrote: I think it has more to do with the government/military original specifications, I would think it goes something like this.. Military "We'd like a M2.5 aircraft..." Manufacturer "Ah but they would require a variable inlet more development work and thats more expensive!!" Military "so how fast can you go without all the extra expence?" Manufacturer " about M2.0" Military " Ok close enough" These figures are then carried through the life of the program, even when those figures are exceeded by a large margin.. cheers A/C top speeds are illusory ... sometimes I think they're based more on what comes from marketing than engineering. The F-14 was attributed with 2.34 (it attained 2.41 ONCE in flight test and was artificially limited to 1.88 in the fleet ... though it got there easily enough). The F-18 has a 1.8 claim ... I know NO ONE who's seen close to that (so maybe once in flight test?). Sometimes I wonder if the marketing guys just go something like "well it's got a thrust to weight of X, it's got them there fixed intakes so it's automatically less than two, and it's not quite as streamlined as an F-16, let's slap '1.8' on it and call it good". Any 4th generation aircraft with fixed intakes is automatically assigned 2 or less and if it's got variable intakes they'll give it a 2.2 or a 2.35. Those seem to be the magic criteria but I doubt they're based on anything but numbers pulled out of somebody's backside. John Cook Any spelling mistakes/grammatic errors are there purely to annoy. All opinions are mine, not TAFE's however much they beg me for them. Email Address :- Spam trap - please remove (trousers) to email me Eurofighter Website :- http://www.eurofighter-typhoon.co.uk |
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