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#61
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The aircraft design philosophies for the USN and the USAF are
different the former concentrates on turn radius performance and slow speed maneuverability around the boat at low and medium altitudes. While the latter (USAF), concentrates on turn rate at faster speeds and at higher altitudes. Current F15 drivers that I have spoken to do go slow in a dogfight depending on the aircraft. Of course, the gist of a turn radius fighter is to turn inside one's adversary thus preferring a one circle fight. Nevertheless, the F15's strength primarily lies in the transonic regime whereas the F14's strength is in the mid to high subsonic regime. The F15 is better by several degrees of turn rate over the F14 in this area while going slower, the F14 has several degrees of turn rate better than the F15. Going to low subsonic speeds, the F15 is a tad better. Going over the M1.1, the F14 is better. What's interesting is that the peak turn rates are equal at combat alittude. Max SEP for both aircraft is the middle of the transonic regime, which, in fact, they are very similar (referring about the F14 F110 engine). During the early stages of ACM/EVAL in 79, the F14A had more than twice the engagements than that of the F15 since the aircraft had to refuel. This was primarily due to the internal fuel capacity differences since both aircraft didn't have external tanks. The USAF's solution to increase the amount of engagements was to add the centerline tank which somewhat evened up the scores. Now to those piper shots, regardless of aircraft, how do you rate a kill? I have seen some F15 HUD dogfight footage in which the pilot calls a kill with a heater yet in reality there was no way he could've hit the plane due to the speed and aspect of the aircraft as he was flying slower. By the time the missile leaves the rail, the targeted aircraft will already be out of the constraints of the seeker. jd |
#62
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On Tue, 28 Oct 2003 15:40:35 -0500, "Tony Volk" wrote:
If all of this were true, the Harrier would be the world's premier dog fighter. it is not. No offense Al, but you're not giving me enough information to be helpful with this comment. As a very quick reply, I would say first that the Harrier has proven itself to be a very dangerous a-a opponent. Second, I would argue that many of the traits of the Harrier would be found in a premier dog fighter (although I'm afraid I don't have detailed performance data on the Harrier). However, more modern designs (Su-37, F-22) have thrust vectoring, with higher t-w ratios, better avionics, more fuel, better AoA performance (I'd assume), and better missiles. So should you have said, the Harrier would posses qualities that make it a dangerous dogfighter in modern ACM, I would immediately agree, and I think both history and training results would back me up. But as the Harrier lacks several of the key items I mentioned in my analysis, it doesn't follow that it'd be the perfect test of my theory. Tony You are advocating bleeding energy in tight turns in order to achieve "first launch". The Harrier is the current leader in such maneuvers, as it can sit in one place and rotate around the vertical axis at will. While the Harrier can be useful against such birds as the Mirage, it cannot live in the same sky with a F-15, 16,18, etc. In addition, I have never heard of a Harrier jock sitting still and rotating while shooting heaters. I am with the folks who maintain that conserving one's energy is critical in ACM. Al Minyard |
#63
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On Tue, 28 Oct 2003 22:50:39 +0000, Paul J. Adam wrote:
In message , Tony Volk writes I don't care what you're flying, if you "turn like' hell" you have blown off all your energy, or at least enough that you can't do anything about me if you even get a glimpse. I can get off a missile before you can, and that's a heck of a something! Missile effectiveness is a pretty direct function of the energy of the launching aircraft. There's a reason why (for example) ground-launched Chapparal SAMs are credited with much less range than air-launched Sidewinders, despite being the same missile. I imagine this is a lot less true for long range missiles such as Phoenix or Meteor. -- "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). |
#64
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On Tue, 28 Oct 2003 19:15:11 -0500, Tony Volk wrote:
Boy, I'm sure getting a lot of mileage out of my posts! Missile effectiveness is a pretty direct function of the energy of the launching aircraft. Let me make an even more direct function. Missile effectiveness is an absolute direct function of whether or not it's on your rails on in the air. Firstly, do you have _time_ to then calculate relative envelopes, select the best weapon, set up the switchology and fire? In modern fighters, this shouldn't be a problem for well-trained pilots (the F-22 has engagement envelopes, etc.). In fact, the F-22's software is reportedly designed to do just that more or less automatically. I would imagine it wouldn't be too difficult for the software to automatically select which missile to fire -- does it do this in any modern fighters? This is the critical assumption. You are NOT firing at each other. Because of your energy-gobbling turn, your missile is in the air first. He can see it, and he'd have to be an idiot, insanely good, and/or a Kamikaze to return fire instead of immediately initiating a break turn. Even if you bluff a shot a little outside of your parameters, can HE judge whether it has sufficient energy? Not very likely (and that'd be one HECK of a gamble!). So you've put him on the defensive, eliminating the need to avoid his missile (see previous conversations for his wingman and other players), and making him use up energy while you can safely regain yours. This suggests to me that in general, the fisrt person to get a missile off is at a big advantage. In which case, doesn't that indicate that the way to go is long range missiles such as Meteor? That's the best way to win (and survive) a modern dogfight IMHO (bearing in mind that I have no access to classified missile/aircraft performance data). A lot can be implied by unclassified data. For example, a piloted aircraft can't accelerate at more than about 9 gees, because it doesn't do the pilot's health any good, whereas missiles can accelerate much more. You can work out an aircraft's acceleration in the direction it's travelling, from it's engine thrust and max speed (which give you its drag at that thrust). Similarly, it's (I imagine) possible to get a reasonable estimate of acceleration for a rocket, given its top speed, and the mass of the propellant. -- "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). |
#65
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In message , phil hunt
writes On Tue, 28 Oct 2003 22:50:39 +0000, Paul J. Adam news@jrwlyn ch.demon.co.uk wrote: Missile effectiveness is a pretty direct function of the energy of the launching aircraft. There's a reason why (for example) ground-launched Chapparal SAMs are credited with much less range than air-launched Sidewinders, despite being the same missile. I imagine this is a lot less true for long range missiles such as Phoenix or Meteor. Not at all. The more energy a missile has when it tries to intercept, the more chance it has to score a kill: just as true for a long-range weapon as a short-range missile. Just pause and consider a target forty miles away and at 40,000 feet; will your missile arrive with more energy if you fire it from sea level or co-altitude? From 200 knots or 600 knots? And is it pointed at the threat or does it have to turn onto the bearing? The two sources of energy for a missile are its own motor (fixed and constant for a given weapon) and the speed and altitude of its launch platform. -- When you have to kill a man, it costs nothing to be polite. W S Churchill Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk |
#66
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In article , "Paul J. Adam"
wrote: Just pause and consider a target forty miles away and at 40,000 feet; will your missile arrive with more energy if you fire it from sea level or co-altitude? From 200 knots or 600 knots? And is it pointed at the threat or does it have to turn onto the bearing? The two sources of energy for a missile are its own motor (fixed and constant for a given weapon) and the speed and altitude of its launch platform. Also add altitude and vector of the target. Shooting down is as much an advantage as ownship speed. -- Harry Andreas Engineering raconteur |
#67
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In message , Tony Volk
writes Boy, I'm sure getting a lot of mileage out of my posts! Missile effectiveness is a pretty direct function of the energy of the launching aircraft. Let me make an even more direct function. Missile effectiveness is an absolute direct function of whether or not it's on your rails on in the air. Wasted shots are wasted shots. You only have a finite weapon load: when it's gone, you're a helpless flying target. There are good reasons to snapshoot a weapon at a threat, even if you're not able to guide it. But there are also times that doing so is at best a wasted shot, and at worst a positive hazard to your own side (an autonomous missile lofted into the blue will tend to attack any target it sees, and they aren't yet able to read insignia). Firstly, do you have _time_ to then calculate relative envelopes, select the best weapon, set up the switchology and fire? In modern fighters, this shouldn't be a problem for well-trained pilots (the F-22 has engagement envelopes, etc.). In fact, the F-22's software is reportedly designed to do just that more or less automatically. Warming up a missile, providing it with a firing solution, and getting it off the rail is not an instantaneous process. While quicker than it used to be, you often still need time to get thermal batteries fired and warmed up, seekers pointing in the right direction, and data messages passed to and fro. Switching between types exacerbates this problem, and may cause problems when your software selects a radar-homer based on the apparently-splendid radar echo of the target... while the pilot fumbles for the manual override, because his radar is actually tracking the target's towed decoy. Secondly, does your MRAAM reliably support a high-off-boresight short-range engagement with a low-speed high-G launch? If the enemy is beyond the range of a short-range IR missile, you have a much lower chance of having to resort to a high-angle, high-g launch than in a quick slashing attack. And even then, the AIM-120C and R-77 are reportedly quite agile. So for BVR engagements, you want to squander the energy you're about to urgently need in order to point your nose and fire back - rather than surviving and evading (while your wingman fires back)? Thirdly, assuming you fire at each other, do you want to be fast (increasing missile lethality and your own survivability) or slow (handicapping your weapons and carving into your ability to evade)? This is the critical assumption. You are NOT firing at each other. Because of your energy-gobbling turn, your missile is in the air first. What alerted you to the enemy's presence (the target and any friends) and how are you confident that there are not already birds inbound? Is his nose pointed at you? If so, you'll get counterfired whether you like it or not, and your bat-turn will probably get you killed when his missile arrives. He can see it, and he'd have to be an idiot, insanely good, and/or a Kamikaze to return fire instead of immediately initiating a break turn. Actually, depending on range and his aspect, the break turn may come much later in the engagement. His evasion sequence might well include a shot back on the same "no point dying with missiles on the rails" principle. And, of course, what is his wingman doing? Bear in mind that one response to your shot is to turn tail and run; at longer ranges it's quite possible to outdistance a missile shot. Meanwhile, you're slow and helpless while your target's wingmen fire back. Even if you bluff a shot a little outside of your parameters, can HE judge whether it has sufficient energy? Not very likely (and that'd be one HECK of a gamble!). But then, at those ranges the enemy has more time to think over his countermeasures (aided by your wilful reduction in weapon lethality) and to plan his counterattack. Would you have been better off taking a shot thirty seconds later, but with much more chance of a kill and more chance to survive a return shot? So you've put him on the defensive, eliminating the need to avoid his missile (see previous conversations for his wingman and other players), and making him use up energy while you can safely regain yours. Trouble is, air combat is a tag-team wrestle rather than a solo duel (with the partner willing to jump into the ring anytime) Meanwhile, how many missiles did you start with? You've now got at least one less, in exchange for a shot with poor Pk. The US may have a seemingly-bottomless supply of weapons, but most nations do not. Are you and your wingman _both_ making brutal turn-and-shoot moves? How long did you spend (a) making sure this really was a 2v2 and there weren't actually four threats or a second section out there, (b) co-ordinating your fire so that you do engage all the threats and (for instance) don't both fire at the same aircraft, leaving the other unengaged? And the point remains... a missile fired from a slow aircraft at a fast target will struggle to hit, compared to a missile fired from a fast aircraft at a slow target. One reason modern Western missiles are highly lethal is that the pilots are trained to use them properly and to fire Taking a shot of opportunity is thoroughly sensible. Wasting energy to take a shot at a poor target... is not. The BEST way to avoid his missile is to make sure it never comes off his rail. By all means, but wasting your own weapons is not a successful means to that end. Dodging one of today's advanced missiles is an iffy proposition, it is far better to gain the offensive, and stay in the driver's seat. But you don't do that by marginal low-energy shots. And you make yourself _much_ more vulnerable if you _start_ the fight by making yourself a sitting duck. Bear in mind that "air superiority" is a means to an end, not an end in itself. If you make a savage turn and a low-energy shot at a passing raid, they may well be able to simply turn away, accelerate and blow by you (and you won't have the energy to pursue, having wasted it in that initial turn) - and they go on to bomb their target, which it was your job to prevent. Better by far to shout for backup while flying a more restrained pursuit, and making the most of your fuel and missile load in killing them or forcing them to abort. You can regain all the energy you like while he's breaking away from your missile(s). No, you can't: I think you've got an excessive optimism about acceleration rates. So again, I think the best idea is to get your weapons in the air (within reasonable, if not optimum, parameters) ASAP without worrying about saving energy to dodge his missile or defeat other bandits. That's the best way to win (and survive) a modern dogfight IMHO (bearing in mind that I have no access to classified missile/aircraft performance data). How are you detecting the foe to make this manoeuvre? (Hint - your sensors look forward, but can be detected over a much larger arc) -- When you have to kill a man, it costs nothing to be polite. W S Churchill Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk |
#68
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As a general response to you and others whom I haven't answered
directly, I'll ask that you refer to previous posts for answers to many of your questions. That is, if you read the entire thread, you'll find that I've already addressed many of your questions. Wasted shots are wasted shots. You only have a finite weapon load: when it's gone, you're a helpless flying target. I wouldn't call a shot that puts you in the driver's seat wasted. Warming up a missile, providing it with a firing solution, and getting it off the rail is not an instantaneous process. While quicker than it used to be, you often still need time to get thermal batteries fired and warmed up, seekers pointing in the right direction, and data messages passed to and fro. You'd have the same problem when making high-speed slashing passes, so your point is moot. while the pilot fumbles for the manual override, because his radar is actually tracking the target's towed decoy. Towed decoy is not for IR as far as I know (and most IR missiles have robust enough AI to defeat flares), and in any case, I have no knowledge of operational decoys, especially those suitable to a high-g dogfight (I'd love to hear about any such decoys if they exist). He can see it, and he'd have to be an idiot, insanely good, and/or a Kamikaze to return fire instead of immediately initiating a break turn. His evasion sequence might well include a shot back on the same "no point dying with missiles on the rails" principle. I would classify anyone who decided to continue maneuvering for a shot before dodging a missile en route as an idiot, insanely good, and/or a Kamikaze. Bear in mind that one response to your shot is to turn tail and run; at longer ranges it's quite possible to outdistance a missile shot. If he runs from your missile, you have a nice easy tail shot for a MRAAM. Sweet! Even if you bluff a shot a little outside of your parameters, can HE judge whether it has sufficient energy? Not very likely (and that'd be one HECK of a gamble!). But then, at those ranges the enemy has more time to think over his countermeasures (aided by your wilful reduction in weapon lethality) and to plan his counterattack. What ranges? In a dogfight the ranges allow more time to think??? Meanwhile, how many missiles did you start with? You've now got at least one less, in exchange for a shot with poor Pk. The US may have a seemingly-bottomless supply of weapons, but most nations do not. Oh COME ON. Conserve missiles for later flights? I don't think so! I'd LOVE to hear a general tell their soldiers not to make less than 100% shots on the enemy so that the missiles can be saved for later pilots! As for the plane in question, it has at least one more IR missile, perhaps 3 more. Given the positional advantage gained by the enemy having to avoid your first shot, you can now take your time with the second shot. Taking a shot of opportunity is thoroughly sensible. Wasting energy to take a shot at a poor target... is not. The idea is to take a shot to create an opportunity. A crude analogy would be throwing a low-percetange jab to set up a hook (assuming that your jab was credible enough that the opponent had to duck/block it). You can regain all the energy you like while he's breaking away from your missile(s). No, you can't: I think you've got an excessive optimism about acceleration rates. His loss of energy in his evasive break is probably greater than your gain of energy through worry-free unloaded acceleration. Bear in mind I'm talking about the newest generation of fighters that have superb t-w ratios and excellent acceleration. I think that address all the unique questions you've asked. BVR, the likelihood of different scenarios, wingmen, etc. were addressed in previous posts. Cheers, Tony |
#69
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Also add altitude and vector of the target. Shooting down is as much
an advantage as ownship speed. -- Harry Andreas Engineering raconteur Not as much as you'd think. Increased air density shrinks missile envelopes. R / John |
#70
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On Wed, 29 Oct 2003 18:04:22 +0000, Paul J. Adam wrote:
In message , phil hunt writes On Tue, 28 Oct 2003 22:50:39 +0000, Paul J. Adam news@jrwlyn ch.demon.co.uk wrote: Missile effectiveness is a pretty direct function of the energy of the launching aircraft. There's a reason why (for example) ground-launched Chapparal SAMs are credited with much less range than air-launched Sidewinders, despite being the same missile. I imagine this is a lot less true for long range missiles such as Phoenix or Meteor. Not at all. The more energy a missile has when it tries to intercept, the more chance it has to score a kill: just as true for a long-range weapon as a short-range missile. Just pause and consider a target forty miles away and at 40,000 feet; will your missile arrive with more energy if you fire it from sea level or co-altitude? From 200 knots or 600 knots? And is it pointed at the threat or does it have to turn onto the bearing? After travelling 40 miles, both missiles ewill be doing about the same speed, I imagine. Though the one that starts higher will get there quicker, and with more fuel (and therefore potential to manouvre) remaining. So it depends whether you count KE or KE + chemical PE. But you asre right in the sense that launching high and fast gives a greater kill probability. -- "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). |
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