AndraxxusTechnically Su-25 could carry 8 Kh-25 guided missiles, more than A-10, which is limited to 6 AGM-65s. Though for similar mission, Su-25 may need drop tanks, reducing number to 4-6 missiles. Also, A-10 carries AGM-65s on TERs, so there are 6 additional pylons for bombs and rockets.
However as the topic is survivability; I believe Su-25 has one clear advantage over A-10 in terms of payload: RWR equipped Su-25s can carry Kh-25MP but A-10 doesn’t have its own anti-radar missiles. On paper, a SPS-141 and Kh-25MP equipped Su-25 can fight againist KUB SAMs that shot them down. A-10 has no real means to do so without getting support from other aircraft.
TBH I have never seen/heard Su-25 on wild weasel role.
Andraxxusi am more interested in thrust at same altitude comparison. Or did you mean exhaust velocity? so basically you’re saying core and fan sections will have thrust curves very similar one to another?
I was talking about thrust. for same altitude, yes thrust curves will be similar. Their peak points may differ a little; ie, fan will reach peak at M0,7 then go down but core will reach at M0,8 then go down, but not much; afterall fan and core will be designed work together. However; due to reasons I’ve explained core will tolerate pressure differences better; at 35000 feet, fan will produce less than 7-10% of its thrust at sea level, but core will produce perhaps 60-70%.
To make some crude paint drawings:
[ATTACH=CONFIG]235573[/ATTACH]
Blue is fan red is core; though there is no 100% correct graph about this. If core is optimized to operate at 20k feet, it will give 100% thrust at 20k and less at S/L.
So in all 4 examples of different planes with different intakes, both fan and core section will still have thrust curves very similar one to another all the way through transsonic region and beyond?
From engine’s own point of view yes, but in overall combination, intake mechanism will cause losses and performance gains; perhaps I should draw this in paint too =)
[ATTACH=CONFIG]235574[/ATTACH]
Red = bare engine
Magenta = Engine with fixed diffuser, diffuser allows faster speeds, but without controlling the shock, engine will stall the second fan face becomes supersonic.
Green = Fixed supersonic inlet with bypass valves; reduced inlet size degrades subsonic performance, bypass valves regulate pressure so flatter peak, then performance drops with reduced pressure recovery.
Blue = Lower Inlet lip controls intake area, engine reaches peak performance and continiously varying inlet geometry holds it close to peak, then drops when those mechanisms are unable to do so.
Is this possible…Super sonic fan like this ?
Possible in theory? Of course, there are even papers about supersonic combustion turbofan. But all those conclude its very impractical.
Technically you can make a scramjet that operates at M0,95 or spend several years in front of a CFD program to build a high supersonic propeller, but these wouldn’t be efficient.
Such efficiencies very well understood these days;
-Propellers are good for making underpowered aircraft take-off and fly slow with high fuel efficiency.
-Turbofans are good for transonic/low supersonic aircraft.
-Turbojets are good for M1.5+ flight
-ramjets are good for M2.5+ flight
-Scramjets are good for M5.0+ flight
-Rocket engines will have similar specific impluse from 0 airspeed to M10.0+
http://en.wikipedia.org/wiki/Specific_impulse#mediaviewer/File:Specific-impulse-kk-20090105.png
I mean if you want supersonic air through your inlet, you may modify the inlet geometry and compress it by shockwaves and remove the fan altogether. engine becomes a ramjet. In fact this is how SR-71’s engines work, at high speed it modifies its geometry so air bypasses compressors and engine becomes a ramjet.
AndraxxusIMO the A-10 is far superior do to design, the armor tub for the pilot, redundant systems and control surfaces. Also the way the wing protects the inlet of the engines.
Su-25 also had redundant systems, and appearantly much heavier armor than A-10. To quote myself (I’ve translated from a source I currently can’t find it on my pc.)
Su-25 has 755 kg armor, compared to ~540 kg of A-10s, and it makes 7,7% of total weight, compared to 4,7% of A-10s.
Su-25’s cockpit armor as follows; titanium armor, 24 mm thick at front and sides, 10 mm thick at bottom and back; rear part of the headrest is 17 mm titanium, sides are 6 mm semi-hardened armour steel. Inside the airframe it has two bulkhead armors made of 20 mm and 17 mm, engine attachment assembly also acts as front armor which is 20 mm thick. They are supported by two additional bulkheads 2,5 mm thick. Engine centerline distance is exactly 1500mm, both engine cowlings and the center fuel tank is surrounded by soft material to catch fan blades in case of engine destruction. Minimum distance between fuselage side armor and the engine is 40mm. Engine is only fully armoured at front half and is 25mm thick at the bottom, and 8 mm thick at sides. Rear half lacks side armor, but has 17 mm plating that covers interior half at the bottom, and the fuselage fuel tank. Starting at the aft of the cockpit bathtub, fuselage has 17 mm armor at the bottom, and has varying side armor thicknesses from 20 mm at front to 2,5mm at the middle then to 5 mm at the rear. Avionics bays at the front and ammunition bay is also protected by 18 mm armor. Tail is not armored, but individual actuators are covered with sheet metal.
USAF used A-10s againist Iraqi army, 4 were shot down. RuAF used Su-25 againist Georgian army. 3 Su-25 were shot down (friendly fire or not). Granted A-10 had far more sorties, but Georgian AD forces had more modern equipment and less airspace to protect. All 7 aircraft appearently downed by KUBs (there are contradicting sources about this, open to discussion), and on many occasions A-10s and Su-25 hit by MANPADS made it back home.
So thick armor is good for small firearms AAA, or MANPAD if pilot is lucky, but it makes no difference to larger SAMs.
What really makes a difference is deployment strategy; On all the occasions Su-25s got hit by MANPADs, it could be avoided if Su-25s had worked from distance by firing Kh-25 missiles. Even using S-13 rockets instead of UB-32s, would have doubled the distance from the enemy fire. But sadly Kh-25 is expensive, and 57mm rockets are not.
Also both USAF and RuAF had full air superiority in both occasions and hundeds of aircraft with anti-radar capability to silence the KUB radars. IMHO, every one of these kills are due to enemy outsmarting the Su-25/A-10 operating airforces on these singular events, rather than the ineffectiveness of the aircraft.
AndraxxusTalking strictly about speed at same altitude, both fan and core will have curves similar to the blue one, and the falling dashed blue line. However its peak point is not necessarily around M1.0, and its not dependent on engine itself but inlet design.
In simplest terms, lets say we have an engine that works between M0 to 0,8 inlet velocity and 120 to 30kpa inlet pressure. It gives its max thrust at M0,6 and 80 kPa air pressure. You put this engine into 4 different aircraft.
First aircraft is a test bed, which installs the bare engine under its wing without putting anything before it.
At 2000 meter altitude (80kpa), graph will raise, reach 100% of max rated thrust at M0,6 and sharply drop to 0 at M0,8. At any other altitude, there will be different peak points, but engine will never reach its max rated thrust. If it tries to climb above 9000m altitude, the engine will stall due to lack of air pressure.
Second aircraft is subsonic airliner; installs a simple diffuser before engine with 30% reduction in speed, and 50% gain in pressure. This configuration has no maintanence, minimal static thrust losses, easy to design and manufacture, and allows sufficient cruising performance.
When this airliner travels at M0,85 at 6000m, engines give their max thrust. Without a mechanism to control supersonic flow, such configuration will stall at M1.0. So your graph will slowly raise to 100%, drop slowly towards M1.0 and sharply zero at M1.0. With additional pressure recovery from diffuser, it will work at 13000m altitude without stalling.
Third aircraft is a fighter; installs a fixed (diverterless or with diverter) supersonic inlet, and bypass bleed valves in addition to above config. Allows supersonic capability, has no maintanence, but relatively large installed thrust losses and poor pressure recovery when supersonic.
Typically diffuser will be bigger than above configuration -to slow high transonic air to engine’s working speeds-, and bleed valves exactly controlling the inlet pressure, such configuration will be efficient at transonic regime, but neither at slower speeds (due to small capture area, inlet mostly remains in suction stage) nor supersonic speeds (due to poor pressure recovery, inlet spillage drag) At 6000m, this configuration’s graph will raise more sharply to 100% at M0,85, drop slowly until M1.0, then drop exponentialy with increasing mach number and zero at M2.0+ It will also have 100% efficiency points at lower altitudes due to bleed valves.
Fourth aircraft is an interceptor. Installs multi-stage variable shockwave ramps, variable lower lip, variable diffuser, in addition to above (fixed diffuser and bleed valves). Such configuration is expensive, and maintanence nightmare, but very efficient throughout the envelope;
At subsonic speeds, shockwave ramps retract, and moving lower lip continiously matches inlet area to capture area, eliminating suction pressure losses and spillage drag. At high speeds, shockwave ramps dynamically control multiple oblique shocks, and moving lower lip minimizes the distance from these shocks (also delaying supercrtical phase, phenomena like intake buzz etc), recovering most of the air pressure at different speeds. Ramp behind shockwave ramps act as variable diffuser, which rotates to get exactly wanted airspeed (M0,6 for our example engine) and bypass system between the ramps reduce pressure to near optimum (80kpa for our example engine). For this aircraft, engine will have high efficiency from 0 airspeed, reach 100% quickly, stay around there as aircraft accelerates to supersonic, and will drop very slowly as aircraft goes high supersonic. Only after one of these mechanisms reach their limits the graph will start to drop exponentially, and possibly will zero around M4.0.
As for real life examples,
-A D-30 engine on Tu-154 will not work above M1.0, but a MiG-31 has no problems going above M3.0, despite its using an afterburning variant of the same D-30 engine.
-Su-24 had top speed of M2.18 but when its variable ramps are deleted, its top speed was reduced to M1.35.
-B-1A had top speed of M2.0+ but when its variable ramps are deleted in B-1B, top speed was reduced to M1.25.
AndraxxusHe is talking about these:
http://en.wikipedia.org/wiki/Virginia-class_cruiser
http://en.wikipedia.org/wiki/USS_Truxtun_%28CGN-35%29
But I agree with totoro. If they are going for nuclear propulsion, and accepting all the additional costs come with it, why make it a 11-12k ton ship with 14k ton full displacement? They could simply put a bigger reactor and make a bigger, far more capable ship similar to kirovs.
AndraxxusHence, the subsonic/high pressure airflow to the LP compressor is NOT a function of aircraft speed.
Well not entirely true. even if completely subsonic, inlet speed&pressure change with airspeed with relation to capture area and intake area (whether spilling or sucking). At supersonic, all these design elements you mention focus on keeping air subsonic -usually- at the cost of pressure loss. Even MiG-31’s more than impressive inlet ramp design will not recover same pressure at M1.2, M2.0 and M2.8.
However you are absolutely correct in that flow is ALWAYS subsonic, and pressure is always regulated within the working boundries of the engine. (so it won’t stall, or it wont destroy itself)
Andraxxuslet me see if i understand it. in a turbofan engine, exhaust of the air both from the fan section and from the core section is never ever above mach 1? and then the nozzle further accelerates the air to give greater thrust?
Correct.
i assume there must be a difference between fan section thrust curve and core section thrust curve, though. at which point does fan section start losing thrust, and at which point does its thrust become less than core section’s thrust? at mach 1 (airplane speed)? mach 1.2? more?
Ok, to be more nerdish:
Thrust = mass flow * (Velocity of exhaust – Velocity of aircraft) – Area exhaust * (Pressure exhaust – Pressure air)
Con-di nozzle merely converts this high exhaust pressure to supersonic velocity. In order to do this, two conditions are necessary; entry pressure must be high enough to choke the throat, and as air will cool within the nozzle, entry pressure must be even higher to maintain stagnation pressure of the jet greater than the environment.
Difference between fan and core section, is the ability to give energy to the flowing air within the engine.
Fan section has a certain pressure ratio. It takes some of the mass flow according to its bypass ratio, pressurizes it, and sends it into nozzle (be it seperate nozzle or merged with core), thats about it. In thin air, pressure drops. In M0,85+ speeds, intake pressure drops. In both cases, Fan has less mass of air to give energy, so its performance drops. It also has less pressure beyond the fan, so its not enough to met the conditions for con-di nozzle to work.
Engine core on the other hand, not only compresses air, but also gives additional energy by burning/heating up the air inside. Core actually uses a small portion of the inlet air to oxidize fuel, and core is primarily limited by turbine inlet temperature, and engine RPM. On typical jet engine, at low altitude, due to high air density, more air is compressed, and more heat is generated (non-isentropic compression). So Air-fuel mass ratio is kept low, so TIT will not exceed design limits. At high altitude, air is colder and thinner. Lower pressure means, less heating up within compressor. When this -relatively- cold air passes into combustion chamber, engine controller can freely inject more fuel to heat this colder air to TIT limit. This will increase the pressure at the turbine section. Ideally, turbine design keeps RPM within limits and this increased pressure is directly translated to thrust. In practice, this pressure will also spin turbines faster, overreving and potentially damaging the engine. Vmax on F-15, MiG-25 going M3.2 are all examples of this.
Afterburner = after the turbine but before the nozzle, air is highly pressurized, and as only small portion is burned, it has much oxygen in it. Injecting fuel will heat up this exhaust, giving more pressure. Othervise air is still sonic during this phase. Limiting factor would be nozzle temperature on the converging part.
Variable nozzle = varies between convergent, and convergent-divergent. On typical engines, its convergent in dry thrust, because engine core cannot meet the pressure conditions I mentioned above. With afterburner, these pressure conditions are met and nozzle expands (not only expands, but also middle section slightly contracts).
What allows supercruising is achieving sufficiently high pressure without afterburner. Typically requires high temperature resistant turbine materials, and more efficient low pressure compressors. Otherwise overall engine design is still the same.
What allows supersonic speed is combination of all engine parts, not one or another. By the way, some 4th gen fighters can go slightly above M1.0 without a supercruising engine, due to viscous effects of air and shockwave geometries, air right behind the engines is still subsonic. So airframe design also plays part as well.
AndraxxusNothing prevents it, it is required in order for the airplane to fly supersonically.
Umm no. In an adiabatic compressible airflow, a fan -by itself- cannot move the air above M1.0. See “choked airflow”. Air compresses with flow velocity nearing M1.0; Increased mass flow will increase density, but speed will stay same at M1.0.
What actually allows supersonic *thrust* is a divergent nozzle which controls the direction of the expension. Without a nozzle, this high density air will leave the fan at M1.0, and expand omnidirectionally. This expension will not produce a net force on a certain direction; as such, this cannot be harnessed as “thrust”. Otherwise while flow may go supersonic while expanding away from the fan, A crticial reason why building a supersonic turboprop is pretty much an impossibility.
BTW; in compressible airflow, technically have thrust can be slower than the airspeed if engine has sufficently high exhaust pressure.
AndraxxusI have to agree with others on this one.
In simplest example, are you SURE about what MiG-35 will use for ordnance? IMHO, if RuAF wants MiG-35 to fill numbers or simply keep MiG company in business, MiG-35 will use pretty much what legacy MiG-29S uses; R-27R/T/RE/TE for BVR, R-73 for WVR, and Kh-31P for SEAD. If however, RuAF wants MiG-35 for a long term lightweight aircraft until they field their own F-35 in 2030 or so, MiG-35 will (eventually) use what is developed for PAK-FA; RVV-SD and RVV-BD for BVR, RVV-MD for WVR, and Kh-58UShKe for SEAD.
All else being equal, a theoratical MiG-35 armed with 2x RVV-BD, 4xRVV-SD and 2xRVV-MD is simply not comperable to the same MiG-35 with 2xR-27RE and 6xR-73 (I don’t think R-77 will ever enter service with RuAF when its replacement is already in trials).
Same apply to LCA which is still on the drawing board. and one can argue how F-16E would be developed by the time MiG-35 or LCA-2 finally enters service. All these would be too much speculation with too little information; leads to nothing.
AndraxxusIdiocy? You’re the only one writing idiotic stuff here. Let’s have a look at the manual then. The manual states that the HEAD-ON CYB (FCS) range (thus, not the missile range) for R-73 is FROM 1.5 UP TO 30 km quote “depending on attack conditions”. So, it drops down to 1.5 km in some conditions and 30 is thus the ABSOLUTE maximum head-on approved-to-fire range at high altitude in ideal weather conditions against I don’t know what kind of fast-approaching IR reflective target.
The manual says “Launch distance calculated by firecontrol system depending on the conditions of attack Hl = Ht = 0-10 km”. So its directly related to missile, not only launch, its also the range missile is expected to hit its target. And it doesn’t say it drops down to 1.5 km, its says you can fire from 1.5 to 30 km. There is a big difference; it says you wont be able to fire below 1.5 km in head-on, no matter what; This is the minimum range, and actual maximum firing range at altitudes less then 10km will be less than 30km, but obviously much greater than 1.5km.
I agree about 30 km is maximum effective range probably for ideal circumstances, with slight deviation from that and the missile will fall short. But again, this applies to all missiles. You talk about head-on ranges, then change topic to maneuvering, or less optimal conditions, compare apples to apples, R-73’s 30 km is in same conditions as AIM-120B’s 43 km, R-27R’s 35 km, and its in same conditions as R-60MK’s 15km. Latter two are even given in the same d**n manual, two pages apart.
Then, 13 km tail chase range? For your info, in a typical tail chase fighter scenario (where the target is not parked) at low to mid altitudes, the R-73 range (0,6 to 13 in the manual) probably won’t be more than up to a few kilometers AT MOST and that significantly drops down with (lower) altitude and the (higher) target speed.
Probably? Yeah very scientific. 13 km tail chase is probably absolute maximum againist a slow aircraft AT SAME ALTITUDE, which is surely at 10km altitude. It drops true, but again, this applies to all missiles.
You’re presenting absolute high altitude ideal scenario maximums as a reference for the performance in a typical engagement and then question the need for BVR missiles at ranges around 12-15 km?
Well, you are correct about the part a R-73 wont have 13 km tail-on range at less optimal firing conditions like lower altitude, lets say, 5000 meter altitude, but neither does AIM-120B (according to graph MiG-31BM posted) nor R-27R (according to MiG-29 manual).
If all speeds/altitudes concerned, 12 km is a range where both BVR and WVR missiles can reach highly depending on circumstances, and neither type of missiles can guarantee a kill. On extreme example, at sea level, it seems an AIM-120B or R-27R can only reach 6 km range in tail-on scenario, and a R-60MK can only reach 3 km. I don’t have info about R-73 for this condition, but it should reach somewhere between R-60 and AIM-120, possibly 5 km.
Your problem is, you are grossly overestimating range of BVR missiles, and grossly underestimating the range of WVR missiles. In fact Su-27SK manual shows R-73 has nearly the same range as R-27T for head-on attacks, and even higher range for tail-on attacks. So it seems BVR missiles are not actually “kill-from-100km” missiles, and WVR missiles are not only “shoot-at-point-blank-range” missiles like they were in 60’s.
And I’m the idiot here? You’re a funny guy, but apparently totally clueless about the topic at hand.
Idiocy is in that you say manual is wrong, and you are right when speaking about R-60MK’s range. How can you be more right than the very manufacturer’s of missile & aircraft?? Manual says R-60MK can be used at 15km, head-on, they even bothered including a large graph only for showing this information. You say “maybe on mars”, laugh at the MiG/Vympel’s own data, and pull a number from your a** without any source or calculation; for the missile designed by Vympel, fired by MiG… They say to their own AF pilots “you can fire this missile from 15 km at these speed&altitude conditions”. Then a forum guy makes a mk1 eyeball inspection on the missile, mixes wikipedia with other forum/article knowledge, and with his limited understanding of the missile, he concludes its seeker is inadaquate or its fuel is not enough. I didn’t call YOU idiot, but what you did was plain idiocy.
Of course, you can question my interpretion (like you say those are absolute max ranges, etc), but I don’t think anyone can question the validity of the manual, other than a typo maybe.
AndraxxusR-60M is rumored to be head on capable. And I don’t think it was for export.
R-60 was introduced in 1974, its generation counterpart is AIM-9P.
R-60M was introduced in 1982 same year as R-73, its generation counterpart is AIM-9M.
IMHO, if Russians are not living in caves, improvement of seeker performance from R-60 to R-60M should be the similar to AIM-9P and AIM-9M.
Andraxxus1) could there be a mistake in translation of the flight manual ? ( for example altitude :km- feet, Nautical miles- km.. etc, max range vs No escape zone) because most source i can found only say the max range of R-60 is only 8 km, if there was no mistake in flight manual then then the Nez is 15 km which mean max range is probably about 30 km that is the significance increase
I think you are mixing R-60MK with R-73:
R-60MK is this:
[ATTACH=CONFIG]235304[/ATTACH]
For 10 km altitude, R-60MK’s NEZ is around 6 km as this is it’s tail-on max range. fire it from 6 km, and it will reach irrelevant of target aspect.
2) from what i understand, the more energy missiles have, the more it can use to turn thus at long range a sustained motor or a ramjet is preferred compared to fast burn motor of Aim-9, R-73
All else being equal, correct. But we are comparing a WVR and BVR missile, all else isn’t equal. Its like comparing Mig-31 and Su-27. Latter will have much better maneuverability even if it is in inferior energy state, because it has more lift and twice G capability. Of course, if Su-27 is in way too low energy state, MiG-31 will turn better, but speaking of missiles, 15 km is right in the middle of the range.
3) are the condition like altitude, launching speed of fighter, flight speed of enemies aircraft is the same between R-73, R-27 manual vs Aim-120, R-77 manual, i did remember reading some where that some missiles producer when calculate max range for their missiles set both 2 aircraft flying at mach 1.2, at altitude of 12 km, while some other set the condition as 2 aircraft fly at mach 0.8 at altitude of 10 km ( i think that will make significant difference in term of range)
Correct, but Su-27SK manual states Hl=Ht=0-10 km and gives a usable range limit. Typically, minimum range should apply to S/L, because minimum at 10 km altitude will be greater, and maximum range should apply to 10km altitude, as max range at lower altitudes will be lower. So all these max values given (30 for R-73E or 65,5 for R-27RE) is for 10 km altitude, comperable with graphs from MiG-29 manual as they also state 10 km launch altitude.
However, it doesn’t specifically give a target speed, so its possible there are around +/- 5km variations between them.
4) from what i understand if 2 missiles have about the same total weight , same motor weight then the longer one will fly further while the thicker one will accelerate faster, i think same case with Aim-120 vs R-73,
It isn’t directly related to thickness ratio but the design of the propellant, and/or nozzle and combustor design for liquid fuelled rockets.
also if iam not wrong NEZ often about 1/2 of max kinematic range?
It highly depends on how long the missile travels in the air. 1/3 is more accurate IMHO.
AndraxxusSurely, you can’t be serious? Locking some fighter at 12 km HEAD ON with these missiles’ IR seeker is very doubtful, let alone the hit chances if the target changes its direction since the missile’s fuel will be long gone by then. And at 30 km, it sounds outright impossible and would make sense for some LOAL IR missile only.
….And 13 km effective rear-hemisphere range?
Sukhoi guys possibly forgot consulting Vympel guys, you should mail them and warn them about missile’s fuel is not enough, and R-73 cannot lock at the range they mention.
[ATTACH=CONFIG]235316[/ATTACH]
12km no-escape zone for R-73?
No, I’ve said as 13 km is tail-on range for a target, its also a no-escape-zone. So its 13 km. I don’t comment about IF R-73 can be evaded. I say (in fact SK manual says), R-73 will need to be evaded because it will reach its target irrelevant of target aspect, below 13 km range.
R-60MK 15 km range? Yeah, right, maybe on Mars….. and that’s even without getting into the seeker limitations (at 15 km with the R-60MK maybe you can lock the sun on IF the atmospheric conditions are ideal 😉 ).. For that missile even the 6 km you mention is wishful thinking.
Well I’ve posted a page MiG-29 flight manual stating just that. If you have nothing more than idiocy to backup your claims, I think I will stick to what flight manual says.
These are very high altitude, fast approaching non-maneuvering target absolute kinetic effective maximums which will not really happen in reality
Then, same goes for AIM-120’s range graph, or R-27R/RE graphs. Technically R-60 is just as capable of hitting a target at 15 km as much as AIM-120B hitting its target at 43 km, or R-27R at 35 km. Not a bit more, not a bit less. If you are defending R-60 has no capability to hit a maneuvering target at 15 km, it may be true, but your logic will also defend AIM-120B has no capability to hit a maneuvering target from 43 km either.
I can’t believe what I’ve just read here..
I don’t care what you believe. By the way, take a look at head-on kill range for R-27TE at column 4 for head-on kill range; educate yourself before trying to be a smartass.
R-27, Aim-120, R-77, Meteor, Mica in general have much better burn time and flight profile for long range engagement compared to R-73, python-5, Aim-9x so at distance > 15 km they probably have much better end game agility
True, but better burn time only improves terminal energy state, not necessarily maneuverability; A G limited missile at M2.0 will turn way better than the same missile at M3.0. And, we don’t have enough info about R-73’s burn/sustain times to make such conclusive assumption. Plus R-73/AIM-9X can pull twice Gs of the R-27/AIM-120.
btw i dont think your statement that R-73E have effective range of 30 km head on at 10 km ( 30 K feet) is accurate, that sound too high for R-73, 30 km probably more like max range,
Not necessarily as R-73 is not exactly a small missile; A R-73E weigh 105 kg, has only 7,4 kg warhead (7%), and a miniature IR seeker. Rest of the missile is a one big booster.
This compares to an AIM-120B, which weighs 152 kg, has 22,7 kg warhead (15%). it houses much bigger ARH seeker (even bigger relative to missile’s size) plus datalink equipment. I don’t think booster of AIM-120B is bigger than R-73E (talking relative to missile size&weight of course).
Of course design priorities and the technology of rocket motor is different, but as AIM-120B has effective range of 43 km at 10000m, I believe its quite possible for a R-73 to reach 30 km effective range at same altitude.
Can you calculate the combat radius of F-15E, F-16, F-35, Eurofighter, Gripen, F-18E/F, PAK-Fa using the same method?
For PAK-FA and F-35, no; too many unknowns (well technically I can, but its possible that results will be way off). For the rest yes, and for F-15/16/18, I can calculate from flight manual. I will make a thread about this when I have free time.
AndraxxusHow many of your alleged R-73 and AIM-9 kills even reached 6 kms in range?
Kills? I don’t know, never bothered to look at it. We are trusting charts to conclude R-27R has 35 km kill range at 10000 m, or R-27RE has 60km, AIM-120B has 43 km kill range at same altitude. I don’t believe WVR missiles deserve any less, so I will post this for R-60MK, from MiG-29 manual:
[ATTACH=CONFIG]235304[/ATTACH]
Technically, even R-60MK can reach 15 km effective range at 10000m altitude.
As for R-73, Su-27SK manual gives for equalized altitude, R-73E has 30 km effective range head-on, and 13km effective range tail-on. So, 12 km is not only a kill zone for R-73, its also a no-escape-zone. It also gives 1.5 km minimum range for head-on shots. so 6 km is actually at the low end of the firing envelope, and 12 km is pretty much in the middle.
Unfortunately, I couldn’t find my AIM-9 charts right now, I will post them if I can. IMHO its safe to say speaking of ranges, AIM-9M is between R-60MK and R-73E, and AIM-9X has better than R-73E, and R-73M is possibly better than AIM-9X.
20%? More than that.
Any kill attained with an AIM-120, AIM-7 Sparrow or R-40 is always a BVR shot. …. And besides, most of these shootdowns happened at night when there was no visability.
I would certainly call 10 km BVR, and even the 6 km as well.
I think you are missing the point. IF those F-15/F-16 didn’t carried any BVR missiles, at 6-12 km, they could have easily used AIM-9M to shoot down their targets. Having already stated the ranges above, the MiG-25 could have easily used an R-60M at 6 km, or MiG-29’s could have easily used a R-73 at 10-12 km, with some luck, even at 25 km.
Visibility would not matter at all, an F-16 pilot could easily switch to CAC, and fire his missile when he has the tone.
So whats the real benefit of carrying a BVR missile here? I am not questioning the BVR missiles in general (its fine if you use them at 40-50 km and hope for a kill), but at 12 km, they aren’t any more useful than a R-73 or an AIM-9. In fact, they have inferior kinematics, have much more weight&drag to degrade aircraft’s kinematics, and exponentially more expensive. If this shot misses, its even more useless after the merge, due to a dozen obvious reasons.
The successful pilots used their radar to detect, acquire and track their targets in almost all cases. The missiles had to use the launching aircraft’s radar and other BVR systems for guidance.
Nonsense. If an F-16 used radar acquire to track its target, and shoot it down with an AIM-9, is this a BVR shot? Or if an Su-27 used IRST to shoot down a bomber with R-27TE from 50 km is this a WVR shot because the lack of radar?
AndraxxusLet me start by saying that by no reasonable definition is 25km ever WVR.
What constitutes “visual range” varies widely depending on the aircraft involved and the conditions. Sure you might technically be able to “see” an aircraft several dozens of miles away under exactly the right conditions. (if the aircraft and/or its contrail is illuminated by a setting or rising sun against a dark sky…) That doesn’t mean you are suddenly “WVR” and in a dogfight.
Even at a range of 10-12km you are only at the very edge of WVR combat in the sense of BFM/dogfighting and you might not even be within visual range in a literal sense if conditions are less than ideal and/or the aircraft you are looking for is small.
Well you are right about all these and general definition of WVR,
But I was talking about missiles and general engagment, and technically at 25 km a MiG-29 can use Vertical scan mode of IRST to automatically lock on whatever there is to lock and use its R-73 at that range. Like I’ve said its debateable if aircraft is actually “within visual range” or not, but a MiG can do away without any BVR capability, and use solely its WVR features at that range. At 10-12 km range, any aircraft can actually use a WVR missile instead of an BVR one.
The next thing you have to consider is that when people talk about a missile’s range, they are generally referring to the distance between the launch aircraft and the target at the time the missile is fired. In head-on engagements the target aircraft will actually cover a significant portion of the distance itself. If an intercept occurs at 10km, 12km, 15km, or whatever, the missile was quite possibly fired while the target was farther away.
Ranges I’ve quoted were actual launch distances, IIRC.
we have people around here who regularly claim that AMRAAM, even the latest versions, really can’t/hasn’t been employed in true BVR engagements.
Well I am not one of them, I do say, some of them were not actual BVR shots, to prove “BVR dominated air-air kills claim” is BS. Actual BVR kills would be around 20% of all kills in last 25 years. Dont get a meaning beyond what I said.
33km + 18km = 51km ~ 32miles.
Assuming 4000 km/h is actually the top speed of AIM-120 at the altitude its utilized (a missile will not reach its top speed at low altitude, just like aircraft); 8 second boost time says average speed is 2000 km for first 8 seconds. Assuming missile linearly slowed to 2000 km/h, average speed in remainder of flight is 3000 km/h. On overall, speed is roughly 2733 km/h. Distance travelled is 22.7 km.
Launch range is 18+22.7 = 40.7 km assuming if MiG is running parallel with no closure rate.
Assuming MiG-29 travels at 800 km/h, it also travels 6.6 km during the time.
18+22.7+6.6 = 47.3 km assuming head-on,
18+22.7-6.6 = 34.1 km assuming tail-on.
Assuming MiG-29 travels at 1400 km/h, it also travels 11,7 km during the time. Launch range is;
18+22.7+11,7 = 52.4 km assuming head-on,
18+22.7-11,7 = 29 km assuming tail-on.
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