Smyth

That's all true, although I would argue the -19P is still more dangerous because Aim-9B make it more difficult for faster aircraft to extend, and the radar only adds <<5% to the loaded weight of a MiG-19. The USSR either didn't realize how lethal a -17F or -19S with R3S would be, or did realize and didn't want to give that to their less-trusted allies. I know the US was 100% expecting to find MiG-17F with missiles in SEA. I should have clarified that I don't think low-speed turns with a -19 are a really good idea in any version of the Phantom, and certainly not the hard-wing flavor. The slatted -E will just pose a non-zero challenge to a -19 driver in a scissors which is maybe a bit unexpected compared to similar-looking 50s swept-wing transonic jets. As seen in the chart I posted above, the F-5E that faces the MiG-19 in DCS currently has really exceptional instant turn rate for a supersonic fighter. Even then the F-5E is quickly destroyed by an F-86 or MiG-15/7 in a slow turning fight, while a MiG-19 of any version takes much more time.

Since I already posted a version of the Phantom vs xxx turn performance summary I was working on for myself in other threads, I think it is only fair to put the full version here for the sake of everyone else interested in this topic. This summary is strictly based on what I can find in publicly-available documents from the original operator (US or USSR), scaled for fuel state and altitude. That correction uses formulas I have validated against available data for aircraft where turn performance is charted at different weight and altitude. The derivation is not overly complicated, but too long for one forum post. Obviously this is not an "official" document despite the data sources, and should be taken for no more or less than whatever it is worth. However I am very confident that this is better than trying to guess based on comparing the un-altered primary sources with their different formats, units, and assumptions. For example the USSR typically uses 40% or less fuel in their charts, while the US uses 60% or more. These are both totally valid assumptions (representing either the end of a dogfight, or the start of one) however a direct comparison is not valid, since turn performance scales quite directly with weight, and fast jets carry a huge fraction of their total weight in fuel. Finally there are three things DCS players should understand before I post this chart: Data for the Mig-23 at 35 degrees wing sweep does not seem to exist. It's pretty easy to show based on back-of-the envelope calculations from aspect ratio what kind of difference that might make (measurable but not enormous), however that breaks the intent of this comparison to use only official data, so it is not included. This chart is only relevant to the real MiG-21, and not to DCS, as anyone familiar with the F-5E vs. MiG-21bis balance in this game should quickly notice. It is always subject to change if any better data is made public. Someone immediately corrected my F104 post with better data, so maybe (hopefully) that will happen here rule 1.16 permitting. With all that said, here it is: Questions, corrections, criticism, and flame wars are all welcome. Enjoy. Post Script: there is "official" data (from McDonnell) that says the F-4E turns better than this, but I did not use that because I don't have proof it is correct relative to the USAF manual. I may be a Phantom Fanboy, but I try to be objective.

Which is fine, I'm not offended if people don't believe me, I just want to make it clear that I am not making wild statements without any kind of justification. I've heard that anecdote before and I can only say I have some... doubts that it was totally objective. However this is a F4E thread not a MiG-23 thread so I will restrain myself from continuing that rant. I think you may be referring to a chart I made, which is based various available US and Soviet manuals including the "Prakticeskaja Aerodnamika Samoletov MiG-23" I mentioned previously. I have a full F-4E vs F-5E vs 21bis vs 23ML version, but the problem is that there seems to be no available official data for non-standard wing sweep positions, so I can only include 45 degrees which will not satisfy this community. Also any 21bis vs F-4E conclusion based on IRL data is incorrect for DCS due to... reasons. Probably I should probably post it to the F-4 section of the forum anyway since it should still generate some interest and (heated) discussion.

A separate post for a separate topic. The MiG-23MS is a totally different jet from the MiG-23S (that did fly - barely). That was the worst model of Flogger. The Egyptian MiG-23MS the US evaluated had exactly the same airframe and powerplant as a MiG-23M (main production, most common and historically significant model) in service with the USSR at the same time. The only difference is that it was lighter than the M/MF and carried lighter weapons, resulting in a more favorable flight performance evaluation than if the US had tested a 'real' MiG-23M. Imagine if the Soviet union got their hands on the lightweight export F-4F, used that to evaluate the performance of the F-4E, and based all their Phantom-lore from it. They would have concluded that an F-4E can turn with a combat-slatted MLD, which it really can't. Likewise the US concluded that a MiG-23M can turn with an F-4D, which it really can't.

I made that statement based on official Soviet data, official US data, and nothing else. This is not the place for a full Mig-23ML vs F-4E performance essay and I don't have the time right now, but here is an estimate for subsonic climb rate since that seems to be the most contentious point. To start with the -23, here is the climb rate plot for an ML from the "Практическая Аэроднамика Самолетов МиГ-23МЛ И МиГ-23УБ" That is 215m/s at 12100kg and 1000m altitude with 2x R-23. Now for the Phantom, here is the climb rate plot from "Limited Performance and Flying Qualities Evaluation of the F-4E with the Retrofit Two-Position Maneuvering Slat Kit" That is 33200ft/min at 10000ft and 37600ft/min at 5000ft Climb rate can be accurately interpolated over short changes in altitude (look at any Standard Aircraft Characteristics page), so for 1000m = 3281ft we get 39110ft/min That is 199m/s at 41185lb and 1000m altitude. Loading says "no external stores", but elsewhere in the report this is clarified as a drag index of 3.2 from the EROS pod and nose boom, which is about 2.5x the drag of an Aim-7, so this is completely fair. 1.5 more Sparrows worth of drag to get the standard 4x will not actually make a measurable difference anyway. That shows the Phantom slightly behind the Flogger, but is it a fair comparison? Not really. 12100kg with 2x R-23 works out to about 28% useable fuel for the ML. 41185lb was 60% fuel for an original Blk36 F-4E. The fuel fraction of both aircraft is somewhat similar, so they should be compared at the same fuel load (generous toward the slightly shorter-legged MiG). Some kind of correction is needed. Climb potential is just specific extra power in different units, so it would work to scale by weight if drag stayed the same. Of course drag doesn't stay exactly the same, but induced drag is tiny in level flight at high speed, so this almost works. To be generous toward the MiG-23, I will scale the Phantom down since that doesn't account for the very small decrease in induced drag. The non-TISEO slatted Phantom at 28% useable fuel with 4x Aim-7E is 38300lb calculated from McDonnell reports (which give a higher weight than USAF manuals, so I use them to be conservative toward the Phantom). 199*(41185/38300) works out to 214m/s. Trying to escape from a Phantom climbing at 214m/s, flying a MiG-23ML climbing at 215m/s is going to be a long wait, unless an Aim-7 intervenes. Note that the acceleration of a MiG-23 IS amazing... when >M1.25 around tropopause. Even an R29 powered 23M/MF/MS easily out climbs and accelerates an F-15 under those conditions. The newer US fighters all feature large wings and turbofans for maximum ceiling and energy retention at high altitude during BVR, and pretty unimpressive raw acceleration at very high mach and lower altitudes as a result. Calculating a similar estimate for turn rate from similar documents leads to the conclusion that a MiG-23ML/A will not out-turn the F-4E at anything other than 16/18 wing sweep setting either. Hence my comment about that wing setting not being a practical one. If anyone can show a better document or better calculation for the excess power of a MiG-23, please share it. I will freely admit I am wrong if such a thing exists. Until then I am standing by this.

That seems to be the consensus around here for some reason, but I still haven't seen any data to suggest that a MiG-23ML can outperform the F-4E in any way while subsonic (including acceleration and climb rate). Certainly the "Practical Aerodynamics" manual for the -23 does not, and it seems likely that the DCS version will be modeled on that document given Razbam cited it for the -19. This assumes the aerodynamic and mechanical limits that prevent the Flogger from dogfighting at the 18 degree wing sweep are actually modeled, but they did include realistic limitations on the Farmer eventually so I have some hope.

Calculated the same way from SAC pages, low altitude climb of an F16A is 270m/s at 1000m and 50% fuel, so it just edges out the F104C. True 4th gen air superiority fighters like F15C will out-climb the Starfighter comfortably, but not by a huge margin (at low altitude... F104 tiny wings don't like high altitude, so F15 and the like can keep climbing where the F104 can't even go while subsonic). Yeah, that was my source. All I did was convert to a more familiar format in an attempt to compare to other jets.

Highly. I don't have any sophisticated metric for this (altitude gained in a spiral, or speed gained/lost in a loop), because those require a full lift/drag/thrust model to calculate. However I do have some official numbers for raw subsonic 1G climb potential. From the 1958 F104C Standard Aircraft Characteristics (declassified). At 1000m=3821 ft we get 47100ft/min = 240m/s at 19201lb which is almost full internal fuel. Now to compare some other aircraft: F-4E (with slats) from FTC-TR-72-35 -> 39112ft/s at 41185lb (57%) fuel Mig-23ML (45 or 72 wing sweep) from "Practical Aerodynamics of Mig-23ML" ->215m/s = 42300ft/s at 12100kg (28% fuel) And for even more laughs: F-14A from its 1977 Standard Aircraft Characteristics -> 42368ft/s at 53166lb (60% fuel) This gives an idea, but the fuel states used by 50s US, 70s US, and USSR are very different. To guesstimate a more fair comparison, I'll use the fact that Climb Potential = Specific Excess Power, so we can multiply by the reference weight and divide by a slightly different weight to estimate climb potential at a different fuel state. This assumes no change in excess power due to induced drag, but the actual change is very small in high speed level flight (few percent) so it is a reasonable simplification (slightly conservative for scaling down the weight of the US fighters, and slightly optimistic for scaling up the weight of Soviet fighters). After some unit conversion, here are the results for 1000m, 50% useable fuel: F104C: 265m/s F-14A: 220m/s Mig-23ML: 200m/s F-4E: 200m/s These are the highest performing tactical fighters of the mid-70s, and they are all annihilated by a ridiculous lawn dart from 1958. Adding 1000lb for an F104G doesn't change much. It's hilarious really, which is a theme for the F104 and the reason I am so excited for it.

Thank you. I was very curious about this topic, so I'm glad the result is interesting to others. That EM diagram for the F-4E is supposedly from a document compiled by Northrop, so I would take it with a grain of salt. I don't think they were exactly lying, but they were definitely not motivated to make generous assumptions for the F-4E (to put it nicely), at a time when the USAF was giving out used Phantoms like candy and that made the F-20 a bit of a hard sell. Sustained turn looks right for the slightly different altitude and weight, but comparing to the V-n diagram in TO 1F-4E-1 there is no way that instant turn line reaches the 30 unit aoa operational limit. Possibly they used the 25 unit recommendation Phantom pilots were trained to follow. I have more to say on the subject but I will save my Phantom cheerleading for a different thread. Just rest assured that I have tried hard to leave my bias out of these charts.

(Edited 9/1): Shortly after I posted this, @IvanK came through with some original EM diagrams for the F104G. Please see his post later in the thread. On the plus side, it turns out my sketchy linear fit got within 4% which is about as good as I could have hoped for. The conclusions remain the same, but I've updated the graphic below with the real data. For a comparison to other cold war fighters, I've taken a graphic I was working on to compare official data for the F4E and Mig-23ML with existing 70s jets in DCS and replaced the F5E with the F104. Hopefully the format makes some sense. The result is pretty much as expected, but it's nice to have a direct comparison instead of trying to eyeball charts in different formats, at different weight and altitude. F-4E is just better at anything in the horizontal, but it's a Phantom after all (I will not shut up about F4 maneuverability). Against the Soviet fighters, an F-104 can technically match their sustained turn rate, but its extremely restrictive instant turn envelope would make that very difficult to use. Overall the F104G is the one opponent where a pre-MLD Flogger might want to take a subsonic fight, however the Starfighter still destroys it in subsonic climb rate and acceleration so even then maybe not. The drastic drop-off in turn performance with the flaps retracted at M0.85 is also going to be a major issue. How much of an issue depends on how flap damage is modeled. There is a NASA document (TN D-6943) investigating F104 handling with the flaps deployed up to M0.94, and anecdotal evidence of an F104 pilot accidentally leaving takeoff flaps extended while supersonic without severe consequences. Ideally Aerges finds a compromise that encourages players to fly realistically, without imposing an arbitrary and non-physical limit. Not exactly, if I understand your question correctly. That sustained turn is only for the flaps deployed below M0.85. Without flaps the sustained turn will be below the maximum G for a while longer, but I don't have any information available to extend that dotted line below M0.85.

This is going to be a long post because I need to explain the basis for the chart I made, so that no one is confused where it actually comes from. Normally I only trust direct turn-rate or time-to-turn charts from official documents, however that doesn't seem to exist for the F104 anywhere. Even the sustained-G charts in the F104 manuals, which could be converted to turn rate, start at Mach 1 and 35000ft. There is a good reason for that, as neither the USAF nor Lockheed wanted to encourage F104 pilots to make sustained turns while subsonic. However this is a flight sim forum and lets be honest -- if/when the module releases most of us will immediately drop the takeoff flaps and pull to the aoa limiter to see what the airframe can really do. At least once anyway. Sadly the TAC report for the F104C I mentioned before didn't work out. The Ps vs Mach curves there cannot be converted into sustained turn at a fixed altitude because they don't intersect Ps=0 below 5G. Without multiple data points for Ps=0 I can't even try to build a trend for sustained turn vs. airspeed. In the picture below it looks tempting to extend the lines down to zero, but after some more investigation that won't work, so we are back to square 1. The good news is that @Bremspropeller pointed me towards another possible source for F104 subsonic maneuverability. Lockheed had a series of lectures for F104 pilots called "Project SURE", and one of them includes a plot of constant-G contours vs Mach and Altitude. With that I can record the intersections of a constant-G curve with a fixed altitude, and fit a trend to those points to estimate what a sustained-G curve would look like at a constant altitude. From inspection of charts for similar aircraft (Mig-21, F-4), they are usually nearly linear up to about M0.85 where transonic drag spikes. Conveniently the flap limit for the F104G is M0.85 anyway, so I don't need to be perfectly accurate above that point. Mig21 as an example to visualize what I am trying to construct: Here is the result: Real aerospace engineers may be horrified at this point, but the fit was good enough that I decided to continue. With the hard part done, I can enter the results into a spreadsheet I have been working on to scale normal acceleration for gross weight, and interpolate to a constant altitude for comparison with other aircraft. Filling in the instantaneous turn rate presented a small problem as well, because the V-n diagrams I would normally use (like what the OP posted) are for flaps raised and don't specify an exact weight. Fortunately there is a stall speed chart for different conditions (flaps up/down, and different stores configurations) at known weights in the F104G manual which I can use to calculate Cl_max with takeoff flaps. Because the F104 has an aoa limiter, that Cl_max should scale well to higher speeds. A sanity check against the V-n diagram shows this is a reasonable assumption. Here is the result. To be exact it is only the shell of a doghouse plot and not really an E-M diagram, and the data basis is pretty sketchy, but I think this is better than nothing. The reason for the 1000m altitude is to enable comparison with other cold war fighters more easily, which I will add soon.

I'm afraid that can't be correct -- Vn diagram suggests maximum lift of around 5g without flaps at that speed. A rough calculation of maximum lift with takeoff flaps and wingtip sidewinders (from stall speeds in TO 1F-104G-1, which should scale up relatively well since F104 "stall" is actually a stick pusher at a fixed aoa) gives CLmax of 0.96, which means 7g still cannot be reached even instantaneously until about ~500kias. Obviously if you have a different primary source I will review my numbers. FWIW that is a slatted F-4E with TISEO (not specified in the title but you can tell from the weight). For the reason I explained above, the best possible case is that an F104G could match the Phantom if it sustains its maximum lift at M0.85. However I am highly skeptical because the Starfighter has less t:w, lower wing aspect ratio, and higher wing loading than the F4E. To back that up, the TAC Mission 857 report (which @Bremspropeller linked above) shows 5g performance contours for the F104C and F4C at sea level. From where they intersect 0 Ps, we can tell the F4C is sustaining 5G at just under M0.6, while the F104C is sustaining 5G at just over M0.6. This is for the light 104C and the hard-wing F4C. Between a slatted F4E and the weight-crept F104G there is no chance (in my opinion). For context, as I have said before and will say again, the subsonic sustained turn performance of the F4 is really exceptional among contemporary M2.0 capable fighters. For the F104 to come anywhere close to a Phantom is impressive enough. Overall the 60s USAF assessments were correct regarding how the F104 needs to be flown. It will rely on subsonic/transonic climb rate, where it trashes ALL F4, Mig21, Mig23, Mirage III/F1, and even the F14A. Combined with semi-decent turning energy retention at >M0.8, that makes loops and climbing spirals very viable and dangerous. In that sense the F104 can absolutely dogfight, just not in the horizontal plane. Regardless, I am trying to derive an approximate doghouse plot for the F104C from the TAC report. That is not straightforward due to the way the data is presented, but I have been unable to find subsonic turn data for the Starfighter anywhere else so it's worth a shot.

So... I know I should have left out that request, but it actually wasn't a rhetorical question, or meant turn into a joke like this. If anyone has evidence of a supersonic turbojet turning best at minimum speed, or perhaps has testing in game that shows the DCS Mig-21 doesn't do this, I really truthfully want to know.

Sorry to fan the flames here, but it isn't helpful to dismiss problems with the DCS Mig-21 module's flight performance as "bluefor asking for a nerf to compensate their skill issue". This can and should be addressed as a technical question. The DCS Mig-21bis module currently has a sustained turn rate that increases down to its stall speed. That is not how any supersonic turbojet fighter performs, for fundamental physical reasons. In other words this bug isn't actually a question of realism, it is a question of physical plausibility. The real world data is only illustrating that. The graph in the bug report is not the best illustration. Here is a different view, comparing directly to the turn rate plots from the original Soviet technical manual. No extrapolation of any kind, and none needed because the divergence from reality and plausibility is fully evident at any speed below M0.6. The real aircraft is losing turn rate while the DCS version is speeding up. No other module in DCS does this, let alone any aircraft in real life. If you believe the Mig-21 flight model is not broken, please present a technical argument that its behavior is plausible and not ad-hominem attacks against those who notice something is wrong. I for one have zero interest in the F-5, and lots of interest in the Mig-21... the real aircraft anyway. The moment the FM bugs are mitigated I will buy it. Until then, not a chance.

From the horse's mouth (McDonnell) circa 1973: "The aft fuselage is constructed of aluminum with the exception of the area subjected to the engine exhaust which is fabricated of stainless steel, Hastelloy X and titanium. Ventilation air and insulation are used where needed to control the temperature of the primary structure"

Not acquiring the target doppler must have been a significant failure mode in the 60s, because one of the improvements made to the F-4 (all versions) radar during the early 70s was a delay relay that gave an Aim-7 more time to acquire the correct target doppler signal. The aspect switch should not normally be involved because it would only be used against non-maneuvering targets (eg. bombers) if the radar cannot acquire a lock. I guess someone could accidentally set the switch to the 'wide' setting (the only position that overrides the radar) for no good reason, but I have no idea if it ever happened in real life. A more likely reason for the speedgate not to lock properly would be if the aircrew does not wait the necessary delay for the radar to provide a stable simulated doppler to the missile. That is the sort of thing that can maybe be simulated on the module side in DCS, although the modules that should currently don't. Regarding maneuvering targets, the missile updates its own speedgate after launch. The launching radar or the manual aspect knob only sets where it starts searching, and for better or worse they have no input after launch. To evade a CW homing SARH missile just by changing aspect, one must change closing velocity by more than the width of frequency range the seeker will sweep after launch, (about -/+150kts on the Sparrow) during the brief time (~1.5s) after the start of the launch sequence and before the missile attempts to lock on. Back-of-the-envelope trigonometry shows that is maybe possible but requires an aspect and turn rate that will probably put the target into the notch anyway.

I am not an electrical engineer, but let me attempt to explain, because the aspect knob is one of the most interesting features on the F4 and F14 radar. The difficulty of pulsed doppler radar processing is that it has to transform the time-domain output of a pulsed radar into the frequency domain, and bin that frequency domain spectrum into different doppler speeds to provide a useful search function that can display the angle and velocity of multiple targets within the scan volume. Try to add back range information (time domain) for RWS, and it gets even more difficult (hence the APG-59 in the F-4J provided only velocity search). The CW illumination strategy used by the Sparrow avoids that complexity (Fourier transforms and any kind of filter bins) by ... not doing any of those things. It separates the transmit and receive antenna so that the illumination can be continuous and pulse-to-pulse coherence is irrelevant. It operates only in the frequency domain, without any way to provide range information. <- edit: this statement is incorrect, it can use FM ranging It does not analyze the entire doppler frequency spectrum, only filter ('speed gate') returns to a specific range and home on the direction of the strongest return in that range. Also, this simplistic two-antenna doppler radar does not actually care if there is a search radar guiding it. The first versions of the RIM-7 Sea Sparrow could be used to upgrade optically-aimed AA turrets, where the operator simply aimed an illumination antenna at the target and the Sparrow guided toward that target with its own seeker as the only radar processing in the entire system. I don't think Karon mentioned in his video that the original purpose of the aspect knob for the APQ-120 is to guide a Sparrow with no range track, or even no radar track at all. That could be useful against electronic warfare if the radar can acquire an angle track but no range track, if the radar is malfunctioning but the CW illumination still works, or even to guide an Aim-7 into heavy clutter (airborne chaff, weather, or ground) where the pulse radar of the F-4B/C/D/E cannot acquire any radar lock at all. In that case the WSO 'locks' the radar straight ahead, and the pilot aims the whole plane like a RIM-7 turret. Without range-rate information from the radar, the WSO uses the aspect knob to let the Sparrow know if it should filter for closing-aspect targets or opening-aspect targets, to avoid locking onto stationary clutter. The "wide" aspect sweeps the whole doppler frequency range and would only be useful looking up into clear sky. Aiming the narrow radar beam at a point is only going to be practical for non-maneuvering targets, so it's clear the feature was intended for intercepting bombers flying through a cloud of defensive chaff, or in the case of radar malfunction on an intercept mission carrying only Sparrows. In a game it would be pretty amusing to use it against fighters flying in ground clutter, which would be unlikely to work well but might scare them at least. Add an optical angle track from TISEO into the mix, and now you have something a bit more dangerous. Unfortunately I don't think DCS in its current state can simulate that level of seeker complexity. Because this feature is very much a corner case in normal operations, the designers re-used the aspect knob to adjust the function of the range rate display. A lot of switches in the Phantom cockpit are re-used like that to pack in analogue systems without the benefit of an MFD.

I recall seeing the Matra 250kg GP bomb on the approved stores list. With only one digit different, that's probably what you are remembering. The US manuals don't discuss the Sparrow in detail (looks like a separate document that has never been released), but the British F4 weapon system manual (CD-101B-0901&2-15D) does, including HOJ for both the Sparrow (meaning Aim-7E specifically in the UK) and Skyflash. Per that document, the Sparrow will break its speedgate lock and switch to HOJ when the jamming signal is strong enough, then attempt to re-lock the target doppler if the jamming signal is lost. If Aim-7E doesn't have HOJ in DCS currently, that ought to be fixed before it is added to a player-controlled aircraft. I think the Aim-7E in DCS right now is really only a placeholder intended for AI aircraft that aren't expected to pose a serious threat to anything (along with other weapons only carried by AI like the R24, AGM45, etc.).

I don't have any real-world data to add on this one, but I do have an observation from the game. Surprisingly enough, the Mig-19 has worse ITR than the Mig-21 and other supersonic jets. I don't have the module, but from watching experienced pilots in cold war multiplayer, the winning Mig-19 strategy is to patiently build an energy advantage with sustained turns and loops. Other aircraft like the F-5 can not only survive at close quarters, but pose a serious threat until the -19 powers away in the vertical. It is a very different fight than an F86 or Mig-15.

What I'm trying to say is that the US Navy F-4 was never flown as an aircraft that "needs a gunpod" in real life, but rather as an aircraft that "does not have a gun". It is an important difference because it changes how performance data should be read. The explanation I've found for the specific Navy doctrine against A-A gunpod employment is that the Mk4 gunpod was not reliable under g-forces, just like the similar Colt Mk12 cannons that were little more than nose ballast in the F-8. In addition, the USN did not participate in the Aim-4D debacle, and never had an urgent motivation to improvise an air-to-air solution from air-to-ground stores like the USAF briefly did. Therefore the most realistic comparison of the turning performance of an F-4B vs. historical opponents does not include a gunpod. In a game of course it can and is an interesting question (see below). I don't think you did either @Aussie_Mantis, I just bring it up because I still hear the "flying brick" repeated constantly as if it is common knowledge. If anything I am arguing against my former self because I used to believe the F-4 brick myth until I started reading IRL data and first-person accounts more closely. Fortunately the F-4C is pretty much an F-4B with tundra tires, and the USAF F-4C manuals provide an approximation. They just treat the 1700lb SUU-16 or 4x Aim-4/9 (with pylons and launchers works out to ~1400lb) as the same loading. This is even more accurate for the 1400lb Mk4 than it is for the SUU-16/23. At 10kft that means: F-4C at 40620lb with 4SP + SUU-16: 10.1deg/s F-4C at 38796lb with 4SP: 10.6deg/s So about 0.5deg/s and of course a ~5% loss of instantaneous g-force just due to weight. Not a big deal against other 60s jets that the F-4B/C/D comfortably out-performs, but maybe not so great against the 70s jets in DCS (Mig-21bis, F-5E, Mirage F1, and maybe in 2wk Mig-23ML) that are close to equal to start. Important footnote: for those who really want to meme hard, the GPU-5/A 30mm pave claw pod was supposedly an *officially approved* air-to-air weapon for the F-4E in the 80s. Heatblur the ball is in your court...

I understand that the F-4B and F-4J cannot engage in a gunfight. Not just without a gunpod, but (in US service at least) practically not ever because they did not carry gunpods for air-to-air combat. On the other hand USN Phantoms were 110% expected to perform BFM. Both Sparrow and Sidewinder in that era were mostly useful in close range (~1mile or less) tail-aspect shots, and a tail aspect Fox1/2 shot requires winning a turn fight first. This is all emphasized heavily in cold-war USN training documents. My main point of course is that the slatted F-4E was improving the subsonic turn performance of an aircraft that was never actually "un-maneuverable" as originally designed and flown. With that being said the ACM performance of a gun-less F-4B/C/D is still relevant and important. I know the lack of cannons may be a deal-breaker to some DCS players but it isn't for me. If my real life were on the line I might feel differently, but fortunately it isn't so I can freely look forward to "flying" a simulated F-4B or F-4J.

Yeah, that's from the same manual. I did also enter the F-4C data into the same spreadsheet I made for F-4E/J. My conclusion is that the F-4B/C/D on equal fuel state has no significant difference in sustained turn to the F-4J or non-slatted E. My attempt to extrapolate the USAF data all the way down to 37500lb to match the Navy graphs under-predicts by the same ~0.2deg/s for both the F-4B and F-4J, however that is still much less than the difference to the slatted E as seen below: F-4C at 40160lb with 4SP + 4Aim4: 10.1deg/s F-4C at 37500lb with 4SP + 4Aim4: 10.8deg/s* F-4B at 37500lb with 4SP + 4SW: 11deg/s *calculated/scaled value Now for apples-to-apples comparison with the slatted bird at 10kft: F-4C with 50% fuel at 38920lb with 4SP: 10.9deg/s* Early F-4E w/ 50% fuel, 40210lb with 4SP: 10.9deg/s* Slatted F-4E w/ 50% fuel, 40480lb with 4SP: 12.0deg/s* An even earlier/lighter F-4B and a later/heavier TISEO-equipped F-4E would close the gap somewhat, but comparing the average F-4B/C to the average F-4E, the slatted airframe appears to win convincingly. Of course, while the sustained turn of the F-4B/C/D may be identical to the un-slatted F-4E/J, instantaneous turn would scale directly with gross weight. The F-4B/C with a 1500lb+ advantage will definitely be closer to the slatted F-4E. I don't think many people realize that the wing loading of 68.9lb/sqf for an F-4C with 4x Aim-9B is precisely equal to the wing loading of a Mig-21bis with 2x R3S at 50% true usable fuel calculated from both aircraft's official manuals. To the decimal place. If the Phantom is the "triumph of thrust over aerodynamics" then I don't know what to call every other contemporary supersonic all-weather fighter. The "defeat of insufficient thrust by even worse aerodynamics" maybe? To summarize the difference between versions of the F4 on equal fuel state: Sustained turn: B/C/D = J < E/S Instant turn: J < B/C/D < E/S Speed and climb: E/S < B/C/D < J As you also noted, everything comes with a trade-off -- there is no free lunch in engineering. In the end I think the slatted E will be the most competitive in DCS multiplayer, however part of me really hopes HB makes the F-4B as their next module rather than a J or S, so we can experience its original design without the later compromises. (As a footnote, I would love to see a performance manual for the British turbofan hard wing Phantoms to compare, but IDK if one exists anywhere in the public domain.)

If the F-4J plot is from NAVAIR 01-245FDB-1T, it unfortunately only includes F-4J and F-4B in the same condition. To make an estimate though, I think in this case it is sufficient to scale the sustained g numbers in the Air Force manuals by gross weight (after converting turn rate to normal force first as required), then convert back to turn rate with ϵ = sqrt(Ny^2 – 1)*g/v. When I did this for myself I just used the early F-4E as a stand-in for the F-4J (thrust, empty weight, and fuel capacity are identical), but we can compare to the F-4J plot as well to validate those results. Here is what I have at 10kft: Early F-4E at 40930lb with 4SP: 10.7deg/s Early F-4E at 42290lb with 4SP+4Aim4: 10.1deg/s Early F-4E at 40930lb with 4SP+4Aim4: 10.5deg/s* *calculated/scaled value Because 1F-4C-1-1 uses one plot to represent either 4 Falcons or 1 gunpod with ~450lb difference between them there is definitely some error, but at least this gives an idea. Now scaling F-4E down to same weight as Navy F-4J graph to validate assumptions: F-4J at 37500lb with 4SP+4SW: 11.7deg/s Early F-4E at 37500lb with 4SP+4Aim4: 11.5deg/s* Next a reference point for the slatted F-4E: Slatted F-4E at 42780lb with 4SP: 11.3deg/s And lastly to answer the original question: How light does the F-4J (or early F-4E) need to be to match a later F-4E with slats? Slatted F-4E (blk50 new built) at 50% usable fuel, 41480lb with 4SP: 11.7deg/s* Slatted F-4E (blk41 conversion) at 50% usable fuel, 40480lb with 4SP: 12.0deg/s* Early F-4E (blk36 unmodified) at 50% usable fuel, 40210lb with 4SP: 10.9deg/s* Early F-4E (blk36 unmodified) at 25% usable fuel, 36980lb with 4SP: 11.9deg/s* If this means anything, it seems to be that small changes from stores drag make less of a difference in a sustained turn than the weight they add. Fuel state on the other hand makes a big difference, so an F-4J at 25% fuel can approximately match a slatted F-4E at 50% fuel (speaking only of peak sustained turn rate). Of course by the same token a slatted F-4E at low fuel is playing in a whole different league.