One of the few good uses for solid rocket motors

[rjaypeters]

Yeah, thats the Tomahawk clone, or near clone. Another good example (along with the F-15/Mig-25) of how similar mission parameters result in nearly identical design solutions.

I must beg to differ, the F-15 was originally designed as an air superiority fighter. The MiG-25 has never been anything other than an interceptor. The Soviet Union's airforce knew the difference, see MiG-29 and Su-27. Now the aircraft become more similar.

[IntLibber]

Yeah, thats the Tomahawk clone, or near clone. Another good example (along with the F-15/Mig-25) of how similar mission parameters result in nearly identical design solutions.

I must beg to differ, the F-15 was originally designed as an air superiority fighter. The MiG-25 has never been anything other than an interceptor. The Soviet Union's airforce knew the difference, see MiG-29 and Su-27. Now the aircraft become more similar.

The F-15 began life purely as an interceptor. I am a veteran of the 318th FIS, which was one of several dozen fighter interceptor squadrons in the 1980's that received the first F-15A/B models to replace the F-106 interceptors we had previously been assigned. There is a range of capabilities under the umbrella "air superiority" (which is just a buzzword for beltway snobs anyways) which include missions such as those performed by the F-16, which is also an air superiority dogfighter whose speciality is close-in dogfighting but which has only half the combat range of an F-15, lower max speed, half the weapons capacity, etc. The F-15 is designed to fly supersonic missions of up to 3000 mile range to intercept soviet bombers, part of its mission profile requires that it carry a radar with a range far beyond that of the F-16.

Similarly, the F-14 Tomcat, is also an interceptor, tasked to intercept the soviet bombers whose mission is to launch supersonic cruise missiles against their aircraft carrier battle groups (said missiles carry 20 MT thermonuke warheads). For said mission, it carries the Phoenix missile with a range of 120 nm, because its target is supersonic, while Air Force's interceptor requirements don't need such a long range missile because the soviet bombers that have long enough range to attack US land targets are subsonic. The Tomcat is also described by beltway desk jockeys as an "air superiority fighter", particularly those who think that the movie Top Gun is an accurate portrayal of top level F-14 air combat training.

The F-15 in later models gained the FASTPAC conformal fuel tanks and additional avionics to give it a wider range of mission profiles.

It just so happens that the look down shoot down radar and long range missiles used by the F-15 and F-14, both of which have the ability to select and target multiple targets at once, without having to get into dogfight situations, is what defines an "air superiority fighter" for the most part. Neither aircraft is particularly good at close in dogfighting compared to the F-16 or the soviet Mig-29 (which is the soviet analog to the F-16). The Su-27 is something of an analog to an F-15 with thrust vectoring included.

The number one rule of air combat is: Speed is life. It really doesn't matter how good your plane is at close in dogfighting if the enemy can shoot you down from beyond your visual and radar range. Modern air to air missiles are generally better at dogfighting than a much larger aircraft, they don't have pilots with g-load limits, and their small size allows for much smaller turn radii. However, if you can outrun a missile, then you live.

[rjaypeters]

I bow to your superior knowledge and experience. However, I invite your attention to just one of the differences between the all of the F-15 varieties and the MiG-25. Down, side and rear visibility for the pilot. The F-15 pilot sits high and has good visibility for dogfighting. The MiG-25 pilot has limited visibility downward, okay to the side and no rearward visibility (short of mirrors).
AFAIK, interceptors of the MiG-25 were intended to close quickly against approaching targets, launch missiles and retire for the next sortie. F-15s are intended to do anything necessary to clear the air of the enemy.

Also, did the MiG-25s ever have a gun? Do I need to go into wing loading and thrust to weight ratios? Sorry, these are more than one thing.

In a gross sense, the F-15 and MiG-25 do share some characteristics, but the details matter a lot.

Certainly, F-14's were designed mostly for the defense of the carrier group. Look at the canopy design (see above points about visibility), they also all carry guns. A generalist design despite its other attributes. Variable sweep wings are useful it close dogfights and landing on carrier decks when your airplane is so heavy.

F-106's were designed initially as interceptors (look at the canopies they first had and the lack of rear visibility). Other missions were added later, as were canopies that were clear directly over the pilot's head.

The F-15 began life purely as an interceptor.

It ain't the Gospel, but Wikipedia disagrees.

It just so happens that the look down shoot down radar and long range missiles used by the F-15 and F-14, both of which have the ability to select and target multiple targets at once, without having to get into dogfight situations, is what defines an "air superiority fighter" for the most part.

So the USAF should have built the near equivalent of the MiG-25 (which had lookdown/shootdown capability - at least later versions) instead of spending all the lovely money for a lighter and more agile fighter which could at least bring the pilot home if the missiles didn't work out?

The number one rule of air combat is: Speed is life. It really doesn't matter how good your plane is at close in dogfighting if the enemy can shoot you down from beyond your visual and radar range. Modern air to air missiles are generally better at dogfighting than a much larger aircraft, they don't have pilots with g-load limits, and their small size allows for much smaller turn radii. However, if you can outrun a missile, then you live.

At the time of the F-15's initial design the longer-range missile armament was the AIM-7 Sparrow. Not the best missile ever in USAF history. I'm sure the pilots appreciated having Sidewinders and a gun, just in case.

Also, I was wrong. The MiG-25 was also used a reconnaisance platform.

[GW Johnson]

If you are actually going to dogfight, combat speed is right at Mach 1 give or take a hundred knots. To fly faster increases turn radius and gets you shot down, but flying too slow also makes you vulnerable. There is also the drag of external weapons, and the fuel consumption of afterburning, when you fly too fast. So it's been "right at Mach 1" for dogfighting, since Korea, excepting only the landing-speed combat operations used by the Israelis during the '67 war, I think it was.

Speed for a fighter is advantageous when you try to outrun missiles (as I saw posted earlier), or when you need to reach somewhere faster than the other guy (rare). Most "dogfights" are really ambushes: 97% of the time, only one of the two pilots knew there was a battle. The loser never knew he was under attack. Even today, a really experienced pilot in a Korean-vintage F-86, retrofiitted with missiles and a radar warning receiver that a good ham radio guy could build, is still a credible threat, because he never lets himself get into a position where he needs the supersonic dash speed.

Speed is more essential to the interceptor, but not as much speed as many folks think. You have to stay out of afterburn, because the interception problem requires you to cross a long range quickly. Mild supersonic is about the limit there. Plus, you generally have to carry weapons externally. Internal-bay weapons have been launched in supersonic flight, but that scenario is fraught with perils to the launching aircraft, since the aero forces on the store far exceed its weight. Slowing to typical 485 knot weapons-release speeds is something the interceptor cannot afford on his mission timeline. It's just easier to kick them off, or fly them off, a pylon, unless you are stealthy. Not many interceptors are.

Ground attack is yet another different scenario. Most of the time it's not speed, it's payload and range that are important, plus survivability or stealth (not usually both). Be careful of demanding extreme stealth, it usually severely compromises other aspects of the aircraft design, even today. Although, it's now pretty easy to incorporate a little bit of stealth into an aircraft without crippling the design. SR-71 was one such successful design, in its A-11 attack variant.

And then there's the Navy. Shipboard launch and recovery impose overriding requirements on the aircraft design, such that these aircraft are generally not so very suitable for dual-use land-based roles. Yet, there are still the fighters, the interceptors, and most especially the surface attack craft. Because of the extra "beef" required of shipboard aircraft to put up with such routinely-abusive treatment, these craft generally have less range than their land-based counterparts. Stealth is far less of an issue, as well.

Air-launched weapons:

I personally think guns are still too neglected. We learned in Vietnam it was a mistake to remove them.

Now, missiles are very useful. One of the most successful of all time has been the AIM-9 Sidewinder series, an IR-guided fire-and-forget weapon, very useful. It's just small and relatively short range. Some of the recent improvements were driven by the need to keep up with Russian designs, but then, that's what it's all about, anyway.

The AIM-7 Sparrow radar-guided series has been replaced by the AIM-120 AMRAAM series. AMRAAM is physically smaller, but flies further and faster than Sparrow, and actually has a significant range for self-guidance, freeing the launch aircraft to engage other targets, sort of a delayed-fire-and-forget characteristic.

There are a whole plethora of standoff ground attack weapons. The most famous is Maverick. AGM-130 is another, albeit less well known. These powered weapons are distinct from guided bomb weapons, in that the standoff range with a powered weapon is usually around 40 miles, while you have to get much closer to use a guided bomb.

And there is the Navy's big HARM anti-radar missile. Very successful, very useful weapon. All the services use it.

Surface-to-air weapons: as part of an overlapping-layered defense approach, the venerable old Russian SA-2 can kock down targets around 60 to 65 kft, except not high-Mach targets. That is why the tri-sonic SR-71 replaced the U-2, and that is why we tried to develop (but failed to field) a supersonic high-altitude cruise missile in ASALM-PTV.

Going airbreathing in the SAM is a good way to make it far more effective at engaging faster targets farther out. See SA-6, Sea Dart, Talos, and Bomarc. The most practical supersonic airbreather for missiles like that is the ramjet, which powered every one of those I just listed.

BTW, it was a venerable old SA-6 that made the only kill on a stealthy F-117 in the Balkans. You can't outrun or outmaneuver this one, once it has a lock on you. Mach 2.8 +/- powered at intercept, some 25-30 km from the launch site. 44 gee maneuver capability. Very simple: built like an artillery round. Very sophisticated: integral booster ramjet-powered, with a fuel-rich solid propellant gas generator instead of kerosene for airbreather fuel. Very old: vacuum tube radar front end, first appeared in the 1967 May Day parade, but went unrecognized as a ramjet in spite of 4 side-mounted supersonic cone spike inlets. Technological "Pearl Harbor" for the West in the 1973 mid east war, because it killed Phantoms 2-3 times out as far from the SAM site as anybody thought possible. Some of these are still out there, too.

[93143]

Speed is more essential to the interceptor, but not as much speed as many folks think. You have to stay out of afterburn, because the interception problem requires you to cross a long range quickly. Mild supersonic is about the limit there. Plus, you generally have to carry weapons externally. Internal-bay weapons have been launched in supersonic flight, but that scenario is fraught with perils to the launching aircraft, since the aero forces on the store far exceed its weight.

Wasn't the F-106 designed for supersonic combat? I believe it and the CF-105 had very similar weapons systems, and I know the latter was supposed to be capable of supersonic engagements.

(There was a silly rumour that the CF-105's weapons pack couldn't be lowered in supersonic flight without ripping apart the aircraft, which is probably true but irrelevant as it didn't have to be lowered to fire a missile; only to swap out the whole pack on the ground... but I trust you weren't talking about that.)

If I'm not mistaken, the CF-105 was designed for at least Mach 1.5 supercruise, and since development went so well Mach 1.8 or even Mach 2+ wouldn't have been unreasonable. As far as I can determine, the Mark II's supersonic combat radius at Mach 1.8 would have been ~350-390 nm (depending on who you talk to), or more than 600 nm with internal modifications for extended range.

These two aircraft were specialized designs, for sure; there are reasons fighter design moved away from the straight tailless delta...

[IntLibber]

I bow to your superior knowledge and experience. However, I invite your attention to just one of the differences between the all of the F-15 varieties and the MiG-25. Down, side and rear visibility for the pilot. The F-15 pilot sits high and has good visibility for dogfighting. The MiG-25 pilot has limited visibility downward, okay to the side and no rearward visibility (short of mirrors).
AFAIK, interceptors of the MiG-25 were intended to close quickly against approaching targets, launch missiles and retire for the next sortie. F-15s are intended to do anything necessary to clear the air of the enemy.

Also, did the MiG-25s ever have a gun? Do I need to go into wing loading and thrust to weight ratios? Sorry, these are more than one thing.

In a gross sense, the F-15 and MiG-25 do share some characteristics, but the details matter a lot.

Certainly, F-14's were designed mostly for the defense of the carrier group. Look at the canopy design (see above points about visibility), they also all carry guns. A generalist design despite its other attributes. Variable sweep wings are useful it close dogfights and landing on carrier decks when your airplane is so heavy.

F-106's were designed initially as interceptors (look at the canopies they first had and the lack of rear visibility). Other missions were added later, as were canopies that were clear directly over the pilot's head.

The F-106 was built in the 1950's when US doctrine assumed all air combat would be missile based, and based on the theory that speed is life, and given the F-106 was the fastest plane in the sky, then naturally there would never be an occasion when there would be an enemy plane on the six of an F-106, so 360 degree view was unnecessary. The F-106 had a few internal bay IR guided missiles (predecessor to the sidewinder) and one radar guided missile with a nuclear warhead whose job was to detonate in bomber formations and shoot them all down with the electromagnetic pulse.

In the 1950's it was assumed that jets, which flew faster than the bullets of the era (there is a famous incident in which one of the Blue Angels shot himself down by flying into his own bullets in a dive) would never experience close in combat again since they increasingly flew at supersonic speeds, so the designs of the era all lacked integral guns (this included the "air superiority fighter", the F-4 Phantom, the F-5, the F-7, F-111 and A-7, etc.).

It was not until the US faced the smaller and more maneuverable Mig-19 and Mig-21 during Vietnam that the error of their judgement was exposed, and gun pods were attached to aircraft, usually underneath the ventral attachment point. It was also in the wake of Vietnam that the US Navy instituted the Top Gun school to teach pilots how to try to dogfight their Tomcats against the smaller and more maneuverable Migs.

The F-15 began life purely as an interceptor.

It ain't the Gospel, but Wikipedia disagrees.

Wikipedia is a bunch of left wing moronic pedants who are so wrong about so many subjects that there isn't a single university in the US that accepts references to Wikipedia articles in academic papers.

It just so happens that the look down shoot down radar and long range missiles used by the F-15 and F-14, both of which have the ability to select and target multiple targets at once, without having to get into dogfight situations, is what defines an "air superiority fighter" for the most part.

So the USAF should have built the near equivalent of the MiG-25 (which had lookdown/shootdown capability - at least later versions) instead of spending all the lovely money for a lighter and more agile fighter which could at least bring the pilot home if the missiles didn't work out?

The number one rule of air combat is: Speed is life. It really doesn't matter how good your plane is at close in dogfighting if the enemy can shoot you down from beyond your visual and radar range. Modern air to air missiles are generally better at dogfighting than a much larger aircraft, they don't have pilots with g-load limits, and their small size allows for much smaller turn radii. However, if you can outrun a missile, then you live.

At the time of the F-15's initial design the longer-range missile armament was the AIM-7 Sparrow. Not the best missile ever in USAF history. I'm sure the pilots appreciated having Sidewinders and a gun, just in case.

Also, I was wrong. The MiG-25 was also used a reconnaisance platform.

Yes, and it is so blindingly fast that, like the F-106, which itself held the air speed record from 1957 to 1965 or so, that it is assumed by its creators that there will never be an occasion when an enemy would get behind it. Max speed of the Mig-25 is mach 3.2, which is only slightly slower than the SR-71, which is why the Blackbird's fighter variant, the YF-12, was considered for the interceptor role in the Air Force (and also had no guns, because, again, it is much faster than the speed of any bullet). At the time, Convair had proposed the F-106X, which would have added square variable intakes like the Mig 25 and F-15 have to the 106, with canards just aft of the intakes. Convair claimed that with a new water/LOX cooled ramjet/turbojet that was proposed, the 106X would reach Mach 5. Convair won the contest on paper, but that interceptor contract was cancelled by Mac the Knife, who prefered to save budget money to fund his baby, the GD F-111, which turned out to be a complete dud.

As for the F-15's long range missile, as said previously, the bombers that targeted land targets in the US were all subsonic, primarily Bear bombers, so the Air Force didn't need longer range missiles, however the Phoenix missile was actually developed for the Air Force (it would have been installed on either the F-106X or the YF-12) and only picked up by the Navy when they determined they needed a longer range missile to intercept the supersonic bombers and supersonic cruise missiles that the soviets targeted the carrier groups with. The Phoenix was built for the Air Force originally because intelligence analysts originally thought that soviet supersonic bombers would be used to target American cities and not the carrier groups.

[rjaypeters]

The other information you and others present is interesting, but beside the point. The F-15 and the MiG-25 look alike, to the uninitiated, which you, surely, are not.

Why was the F-15 designed with features (canopy design, gun, thrust to weight ratio, wing loading, etc.) which are not needed when speed is life for an interceptor (i.e. missile-based air superiority)? Because those design elements were needed to fulfill needs other than pure interceptor.

[IntLibber]

The other information you and others present is interesting, but beside the point. The F-15 and the MiG-25 look alike, to the uninitiated, which you, surely, are not.

Why was the F-15 designed with features (canopy design, gun, thrust to weight ratio, wing loading, etc.) which are not needed when speed is life for an interceptor (i.e. missile-based air superiority)? Because those design elements were needed to fulfill needs other than pure interceptor.

Again, you fail to read what I have said. The characteristics you cite pertaining to the F-15 are the result of lessons learned from Vietnam and our air combat failures there, not due to any specific prescription or definition of "air superiority fighter". The definition of an "air superiority fighter" changes with each and every war as the jets of one generation expose their flaws when they meet jets following different air combat philosophies. You are confusing effects with causes.

[rjaypeters]

Yeah, thats the Tomahawk clone, or near clone. Another good example (along with the F-15/Mig-25) of how similar mission parameters result in nearly identical design solutions.

I've read every word you've written on this thread about fighter aircraft. I even understand all of it.

Okay, your turn. How are the F-15 and MiG-25 nearly identical design solutions?

[ladajo]

As I recall the Foxbat was quick like a bunny for ballistic flight profiles, but was outclassed in the turns. The word brick comes to mind.
F-15's can make the circle. And, in a knife fight, it is about the circle and who can make it smaller and faster, add in Boyd's OODA and you get winner every time. I don't think he ever lost the bet.
Is not Foxbat wingloading almost twice that of the Eagle?
Is not Eagle thrust to weight more than twice the Foxbat?
The Foxbat is a big heavy and straight line fast. The Eagle is pretty much the same size at half the weight (more or less) and with better pushers which makes the Eagle fast AND maneuverable.
Apples and oranges again, the planes do not compare.

[GW Johnson]

The Convair F-106 was an interceptor, not a fighter. It could reach around M1.6 in level flight, but the supersonic range was very short. Essentially you had to fly the range at high subsonic and accelerate to attack at the last minute. Weapons were carried in a bay, not underwing (drag too high for supersonics even in afterburn with external weapons). Those weapons were early AIM-7 Sidewinders, the Hughes GAR-something-or-other Falcon (both IR and RF guided versions), and later the AIM-9 RF-guided Sparrow. It could also carry the Genie, which was an air-to-air nuke.

Although designed more as a fighter, the F-101 Voodoo had good enough interceptor characteristics that it was actually preferred over the F-106 in the interceptor role. Much better range at higher average speeds.

F-106 was the "corrected" version of the earlier F-102 design (both delta-wing single-engine aircraft). F-102 was the same basic airplane, less capable engine. Never actually was able to go supersonic, except in a dive.

BTW, Mig-25 Foxbat was an interceptor, not a fighter at all. No internal weapons, pylon carry only. Clean, its top speed was reported variously as M3.2 to 3.5. I tend to favor the 3.5 figure. Trouble is, it was placarded to M2.8 max due to aeroheat and vibration problems with external stores under the wings. Between that and its short range, it really wasn't the fearsome weapon many think. Plus, the engine life was very short: about 500 hours max. Most of the time, far less than that.

Mig-25 was the counter to the M3-3.2 XB-70 we decided not to produce as an operational bomber. Mig-25 intercept of B-70 would have been problematical at best, at no more speed than the target bomber, and well nigh impossible carrying any weapons. Its most memorable service was setting speed and altitude records as the EA-166, in competition with our SR-71.

[krenshala]

To me, The MiG 25 looks more like the Tornado than the F-15. Of course, I'm a USAF-brat that did 10 years in the AF myself ...

As I recall the Foxbat was quick like a bunny for ballistic flight profiles, but was outclassed in the turns. The word brick comes to mind.

The Brick was the F-4. A brick with rockets and steering vanes (my dad worked ATC for most of his 28 years in, and he told me it was known as the brick because it had the glide-path of one.)

And as other folks have said, the lessons of Vietnam air-combat were mainly, "even if you use high-tech missiles ... you can run out and need a gun to get the job done." My understanding is the commander over there decided to order his own missile pods (he'd been told by higher up that "they aren't needed") or the F-4s would have fared even worse.

[ladajo]

Yes, that was where I drew the word from. I am personally a great Phantom fan, have been for years. But, I did deserve the nickname.
Not only did it drop like a brick, it turned like one too, especially at speed.

[rjaypeters]

The Brick was the F-4.

AKA "America's proof to the world anything can fly if you have enough thrust."

The next and greater proof could be the Bussard-powered SSTO or zero stage.

[kunkmiester]

Those weapons were early AIM-7 Sidewinders, the Hughes GAR-something-or-other Falcon (both IR and RF guided versions), and later the AIM-9 RF-guided Sparrow. It could also carry the Genie, which was an air-to-air nuke.

Got your missiles mixed up--AIM-9 is the Sidewinder, IR guided. AIM-7 is the Sparrow, semi-active homing--plane lights up the target and the missile follows the reflected radiation in.

IIRC the AIM-9 was pretty good then, but the Sparrows took a while to become reliable.