esb77

As far as I know none of the submunitions for the weapons available for the Su-25 variants in DCS are smart submunitions. The PTABs are I believe top attack munitions, and the heavier ones (fewer per container of a given size) are the ones meant for anti-armor as far as tanks go. KMGU-2 96 PTAB-2.5KO RBK 500 PTAB-10-5 RBK 250 PTAB-2.5M The lighter PTABs are good for soft targets and will often take out APCs/IFVs as well. They may or may not work against MBTs depending on how many hit. RBK 500 PTAB-1M There is a smart munition RBK 500 SPBE-D with smart munitions in the Encyclopedia in game, but in the mission editor it doesn't appear to be available for any of the Su-25 variants, or even for more modern AI planes like the Su-30 or Su-34.

Approximately yes, though if you're measuring from the center of the round the width of the rounds might make it about 7 inches. It works out to something like 1.7 MOA, and a good sniper or target rifle will yield around 0.5 MOA, (or if you're lucky and spend a lot of money maybe even as low as 0.25 MOA). So it's not superb accuracy in terms of what's technically possible, but 1 - 2 MOA is achievable for mass produced small arms, and 20 and 30 mm are still close enough to that size so that it wouldn't be a particularly astonishing level of precision. In most cases though, on the aircraft between engine, aerodynamic, mechanical from auto-fire, and other sources of vibration and flex, I'd really expect that stability of the platform is going to be more of a limit on how precise your groups are than the quality of the gun and ammo once the manufacture of the weapon is reasonably high quality. Edit: Honestly, up to a point especially with a high rate of fire gun like the Vucan, bigger less precise groups are potentially an advantage. When shooting down birds on the wing there's a reason shotguns are preferred over rifles. ;) The Ka-50 has good reason to want a real laser gun of a cannon to put rounds into armor where it hurts, but for the planes 0.5 mil precision may be a bit too much of a good thing.

If the LUAs are in radians, which they may or may not be: 0.0005 radians * 1000 milliradians/radian = 0.5 milliradians 0.5 milliradians is equivalent to one half mil, not 5 mils. 22 mils, which is what you were citing, is 44 times 0.5 mils, which is what your interpretation of the LUAs being in radians would yield if the math is done correctly. I discovered this because I wanted to convert to MOA, and I couldn't get your source numbers to generate a MOA reading that was equal to 22 mils. I got as far as differential equations in math, so of course I no longer really trust myself to remember simple things like arithmetic correctly, but for what it's worth, my expensive graphing calculator agrees with me that you're multiplying by 10000 when you should be multiplying by 1000. The math as done by a Ti-89 0.0005 * 1000 = 0.5 0.0007 * 1000 = 0.7 0.0022 * 1000 = 2.2 You are being consistent though, so when you start multiplying by the correct 1000 conversion factor when going from radians to milliradians, you should start getting consistently correct results. You didn't specify in the first post, so I though you had just misplaced the decimal when looking at the F-15, I didn't realize you were doing it for all of them. So I compared a correct value of 0.5 mils with your incorrect value of 22 mils to get a roughly 40 times difference in dispersion. As far as the LUA values go, in whatever unit they really are, 3-4 times more dispersion compared to a round that's 50% greater diameter is within the realm of reasonable, especially when you get out to 1000 m or greater ranges, but a lot of that is also gun construction and ammunition quality, so a dispersion for a 20 mm that's half of a 30 mm's is also possible. I was just trying to very indirectly point out that if your theory that the LUA values are in radians is correct, then if the math is done correctly, a value of 2.2 mils is well within the expected amount of 8 mils for the F-15's gun.

In the style of math that I was taught in school, when performing arithmetic operations in base 10 1000 * 0.0022 = 2.2 Not 22. By the LUA numbers you cite the F-15's gun has 3 to 4 times the dispersion of the Russian 30 mm guns, not 40 times.

Keep in mind that especially for instructional materials written aimed at civilian aviation, the assumption is that initial training aircraft will not have a HUD. They might not even be IFR rated aircraft. The main concern is that since students start with VFR and will be flying solo after not really all that many hours, keeping eyes in the pit is an extremely dangerous habit. In VFR keeping eyes out of the pit is the only warning system for preventing collisions, mid-air or with terrain. When the pilot starts to solo, there's no Instructor Pilot to start screaming in terror because someone is so fascinated by their compass heading that they haven't noticed a looming mountain. It's bad form for an Instructor to lose students as soon as they start soloing because the Instructor never bothered to teach them to watch where they were going. Not to mention that blind blundering around tends not to make friends with the pilots that you near-miss. Then when they start yelling on the radio ATC may get upset, when they file reports with your aircraft ID calling you a dangerous idiot the national aviation authorities get upset, etc. The point was that eyes out is the "official" preferred primary source of information for pilots. You check the pit as necessary. It's nice to know if instruments agree that things look ok really are ok. After checking, you're eyes out again though. In IFR "as necessary" might be nearly continuous, but it's continuous because there's no choice, not continuous because the instruments are preferred over the view out the windscreen. This is sort of derailing again though, so I'll stop with the general aviation stuff since this is supposed to be F-15 specific.

Ok, I managed to come up with a slightly more understandable explanation than my previous one. At least I hope it's more understandable. Ironhand got the core of the problem, obeying the laws of physics. This all based on physics, and physics as currently understood demand conservation of mass and energy. That means that a math model of a physics problem has to obey those laws. bbrz was using a purely positional model. You could call it algebraic, geometric, or analytic geometry, because mathematicians aren't always sticklers for consistency in naming. Whatever you choose to call it, it is inadequate as a good representation of the aspects of landing a plane brought up in this thread because it can't keep track of the conservation principles demanded by physics. For that you need vector mathematics. The motion of the plane as being talked about is the sum of four vectors: thrust, drag, lift and weight. It is possible to change these vectors and still arrive at the same sum. Then with that force vector you can go on to calculate acceleration, velocity, and finally, position. Trying to skip straight to position does not give accurate answers. Here's an example of different input vectors resulting in the same sum. If thrust = (5,0,0) and drag =(-2, 0, 0) then the result in a standard Cartesian coordinate system is 3x. Change that to thrust = (7, 0, 0) and drag = (-4, 0, 0) and the result of summing them is 3x. Vectors behave a bit oddly compared to the math people learn before encountering them, which is why students encountering them often struggle a bit. They don't act quite like people who've never seen them before expect them to act. Before I digress too far on mathematics, the salient point is that there is a lot of scope for decent rate to remain the same with other parameters changing as long as the net sum of force vectors acting on the plane remains the same. bbrz performed their math correctly, it just wasn't the correct form of math for modelling the system in question. It was a good effort based on incomplete understanding of how to solve the problem. That's not the only incomplete understanding of things from bbrz. The folks at the FAA who write things like their Basic Airmanship Manual (available free as a PDF), and presumably know something about training pilots in real life, spend a great deal of effort to encourage pilots to avoid being "head down." Translating from aviation speak to English that means, "don't look at the instruments, look out the cockpit canopy." If you ever watch videos of instructor pilots with new students you'll notice that instructors do a great deal of telling student pilots to stop looking at the instruments and look out the canopy. There's a reason for this. Humans are really bad at instrument navigation. The instruments are a backup in case looking out of the canopy doesn't work. You don't fly tight formation in bad visibility in real life. You don't land manually if there isn't decent visibility at ground level in real life. Human pilot IFR is an approximate navigation system, not a precision navigation system. If a human pilot can't land visually for the actual touchdown, they'll get diverted to somewhere with better visibility. For really low to zero vis conditions landings are handled by autopilots at airfields with compatible precision landing systems. The airfield portion of the system provides a reference to compensate for errors or drift in the aircraft instruments, and the autopilot prevents the human pilot from making the mistakes that are expected even from human pilots with IFR ratings and thousands of hours of flight experience. People just aren't good at monitoring many instruments at one time, and they're also not very good at turning instrument readings into an accurate and up to date idea of where the aircraft is and how the aircraft is moving. Treating a human IFR rated pilot as a precision navigation system in very low visibility has resulted in what's called, "controlled flight into terrain," so many times in the history of aviation that aviation authorities have developed extensive rulesets designed to discourage pilots from being foolish enough to think that a set of instruments and an IFR rating will allow a safe landing when below IFR minimums.

bbrz is right about the glideslope geometry. Sort of. More specifically, right if all bodies are measured in the frame of reference of the airfield talking about speed along the glidepath. AoA and IAS are both in the frame of reference of the aircraft and compare the motion of the aircraft relative to the air, not the ground. Most of this argument is people forgetting or not knowing precise definitions and the implications of those definitions, The math and physics checks out, if you do it right. Edit: I'll admit that it took me a little while to figure out how bbrz could be doing the geometry right and everyone else could be doing the airmanship right and yet somehow getting different answers.

I've never seen such charts. There are partial answers in the documentation, and there's a manual in Spanish that you might be able to find by using advanced search of this forum. Not enough to calculate it for a particular runway and conditions though. Most of this stuff you can flight test in the sim if you want to. At one point I did most of them for the Su-25T in DCS, and I think it took me about a week of flying test missions a couple of hours per day. For landing speed, the best solution is to not do it based on speed. Instead do it based on AoA. When you're on final get yourself in landing configuration with gear and flaps, speed to around 300 km/h IAS, and then trim to your desired landing pitch. I can't remember what that is supposed to be for the Su-27, but my guess would be somewhere around 12 to 15 degrees. A few degrees less than what would produce a tailstrike on the runway. Use the stick for fine control of AoA to keep it exactly on target, and then use the throttle to control your altitude and stay on glideslope (increase throttle to gain alt, decrease to lose alt). This method will automatically manage your airspeed to be appropriate for your aircraft weight if you are staying on slope and at the correct AoA. That said, if your IAS is below 240 or above 330 you might want to abort and go round. Vne generally requires a clean plane and several minutes of full AB, so isn't really an issue unless going for a speed or climb to altitude record. If you have more than just a few stores there will be so much drag that you won't be able to reach Vne. I know the flaps are controlled by the flight computer in normal operation, but I don't remember if having manual control set to down will override this and allow you to break them by overspeeding. I'd have to fly it to check.

This sort of varies by mission author. It's possible to have a very clear mission briefing, an in mission message (voiceover even if you get fancy) triggered by completion of mission objectives (can even be multi stage objectives ), and at the scoreboard to list a mission success/fail message, and in a campaign have different follow-up missions based on success or failure. The mission author can also choose not to have any mission objectives. If you learn to use the mission editor, you can alter the mission objectives, at least in missions that don't have copy protections. "It depends," isn't the most satisfying answer, but that's the way it is.

There's this thread https://forums.eagle.ru/showthread.php?t=190912 where neofightr discusses how the USN has its pilots do carrier landings, among a variety of other topics. Actually, here's the relevant bit, since there's a lot of stuff to dig through to get to the relevant bits (much is worth reading, but there's a lot of off topic with respect to landing). The condensed version is that when flying the final approach you use the stick to control not your pitch, but your AoA. The throttle you use to control your altitude above or below the glideslope. Horizontal alignment you correct as needed with roll and yaw. A natural question is, "but if I'm controlling altitude with throttle, how do I control my speed?" Mostly the answer is that you don't need to worry about it. If the plane isn't overloaded with fuel and stores and is in landing configuration (part to full flaps and gear down), the speed will pretty much take care of itself if you're keeping reasonably close to glideslope. It may feel odd if that's not the way you're used to doing things, but it does seem to produce consistently good results, which is very desirable when landing an airplane. I'm sure somewhere there's an official number for the Su-25T, but in the absence of knowing what exactly it is, I find that keeping the needle on the AoA gauge at about 10 works fairly well. Unlike a carrier landing, it is advisable in a Su-25T to flare (in the increase AoA sense not the deploy countermeasures sense) in the last few hundred meters just before landing. In terms of amount, just enough to get your decent rate to the 0.5 to 1 m/s range at touchdown.

Wipe off more dust or wipe off less dust, either might help. Other than that it looks a lot like glass or plastic covered displays under direct sunlight. Can't read a bloody thing until you move a hand to shade it. Either that or you need glasses or a visor that are polarized. Though in the case of display screens that are polarized things can be just as bad with the filter as it goes either completely dark or turns a sort of rainbow/oil-spill color and the glare is gone but you still can't read anything. So I guess they should implement a helmet visor setting? Those aren't just plain white overlays though. It looks like an alpha/transparency layer with a gradient oriented toward the sun as a light source. It's just that the saturation is so high that you have to look really closely to see the gradient.

Ah, well I didn't test in MP. For what it's worth, I think it'd be cool if they made it work for all player controlled planes in MP and not just the local client's plane. Flying formation when it looks like you're the only one that doesn't have hydraulic failure (or ramps in emergency mode) would definitely be weird. I doubt they'll make an announcement about any plans they do/don't have for it. The little cosmetic fixes tend to just appear with no warning in the change log notes whenever they get around to them. If you can get a lot of people to mention it where ED/Belsimtek see it I suppose maybe that increases the chance that it gets addressed at some point. We can hope anyway.

The internal ramps that slow down supersonic airflow to get it subsonic before hitting the compressor fans do not have animations. The external intake/ramp, labelled "ramp 1" in the diagram in the article you link, behaves as the article says it should. On the ground with engines off it's up, on the ground with engines on it's down, and in flight it tries to remain parallel to the airflow, ie. maintain a 0 degree AoA. Do you have any documentation describing that details of what you think is wrong with the model in DCS? You complain that it is not right in the sim, and then you link supporting evidence (though not a primary source so probably not good enough for ED/Belsimtek) that indicates that the sim is right. If you want a change to the external ramp animation, or for the internal ramps to get an animation, I think perhaps you need to state more clearly exactly what you want changed.

A move is in progress, the place to look is here. I think he has only moved 3 F-15 specific ones so far, but more may be coming.

My admittedly sketchy and unreliable survey of radio navigation in 1944 Europe would suggest: NDBs of 1930s vintage AM radio stations, that the Germans probably discouraged from transmitting. Gee Oboe LORAN (not sure the Scottish/Faroes/Shetlands stations' signals would have reached to the Normandy region). Radio communication with British radar operators. So basically, compatibility for the more modern aircraft would mostly be with the map, chronometer, slide-rule system. Maybe NDBs if you're lucky. Also given the era, the nighttime light discipline should be pretty good, so don't count on using the lights of inhabited areas for navigational purposes. Oh, and this is an area of the world renowned for it's fog and low level cloud cover during large parts of the year. "Hey, Bud, how's our dead reckoning coming?" "Well, Cap, I reckon we're dead if we try to put down in this soup, but if we bail out I think we might land somewhere in Wales." Remember kids, always check the weather before you take off.

I tested too, and managed to get up to 900 km/h IAS and full deflection without any problems in level flight. Mind you, that's using the rudder, not stomping on the rudder. I haven't tested much with maneuvering through other rotational axes though. My expectation would be that rolling would be a problem due to the side load a roll places on the stabilizer, pitch might be o.k. or might be a problem depending on where vortices are, so might be highly variable depending on AoA. Not sure I feel like doing that much testing at the moment though.

I think that Frostie is pointing out that the western aircraft as currently modeled in DCS have simple point flares, possibly with spectrum matching, and that the CM rejection of the R-73 should be able to reject them quite handily in most cases post lock. At least in small amounts. For the IIR seekers, at present, if you want to use a flare the thing to do would be to use the ultimate flare, which of course only works during daylight hours and above the cloud deck if the weather isn't clear. In cloudy weather, if the clouds are thick enough, then I suppose you get to play 3D hide and seek. The physics of the article are pretty much what you'd expect. Make a hot screen between you and the missile, hide behind it, and if it's a gate based track get as much clutter as you can in the background. The other interesting approach would be to put a cold cloud between you and the seeker. Water mist, IR tuned chaff, or something along those lines. Likely to be a bit heavier than pyrotechnics though, and you'd still have all the tail chase hide-behind-a-bush sorts of constraints that a volumetric flare approach would have. Sun, clouds, element of surprise, and stay behind their 3-9 line. Looks like the AIM 9X hasn't really advanced air combat much beyond what the guys flying Sopwiths and Fokkers were doing. ;) Hell, just pop the canopy and throw a brick at the offending 9X platform.

The damage model runs on a fairly simple hit points based system. The tanks have facings, front, rear, top, left, and right but there's no differentiation between armored and soft targets other than the number of hit points. Meaning if you have enough ammo, you can take out a T72 or Leopard with an M-16 or AK-74. In addition, in order to somewhat mimic the blast and shrapnel effects on soft targets at one point most or all HE round and warheads were given larger radii and higher damage numbers. Combine those two traits and you get HE being more effective against Armor than AP. ED knows that this model is deficient, but with things like a new graphics engine, Nevada and Hormuz maps, collisions for trees, new aircraft, flight model updates, Naval ops, etc., etc. redoing the damage modelling system for ground units and then redoing all of the data for ground units in the new system is not that close to the top of the priority list. I'm sure they hope to improve on it. Some day.

It doesn't really get interesting until around page 18, where it starts going into depth about vortex lift effects, but from there until the references at the end it is a wonderful read. If you don't mind Swedish grammar, or more specifically the grammar of Swedish engineers. Thank you for the reference. I'm slightly jealous of virvel as a word root compared to whirl or vortex, now. Are aerodynamic texts supposed to have linguistic side effects?

I could have sworn that I read somewhere that Soviet design philosophy for the Su-27 was based on the notion that the majority of air combat scenarios would be resolved in the WVR arena. That being the reason that they had IRST and high off bore helmet cueing systems as standard features long before the US did.

So here, courtesy of the illustration powers of KSP, is a brief lesson on center of lift. Every lifting surface has a center of lift. This is a theoretical tool that allows you to simplify calculations by finding the point where a single large force produces the same behavior as evaluating all of the small amounts of lift provided by each infinitesimal area of the wing. No one wants to do 200 trillion calculations by slide rule to figure out what a wing is going to do. For weird situations, like around the AoA where separations occur, this doesn't work quite as simply, which is where the power of modern computers and CFD comes in, because then you can do calculations for each little bit of the surface. Anyhow for a delta wing the forces diagram looks about like this: The blue arrow is the lift vector through the center of lift, the yellow ball is the center of mass, and the elevon is highlighted in green. https://www.dropbox.com/s/s2k3nnktakrq3f4/VigFigOne.jpg?dl=0 The problem here is that the downward force of the mass is far from the center of lift, and is pulling the nose down quite a lot. So the elevon has to produce a lot of down force to counteract that torque. It makes trimming things nicely a pain, and the elevon is using a lot of it's control authority just to keep the nose from sinking. Now add in a set of canards, fairly large fixed leading portion with a flap, just as in the Viggen. Also give the canards a few degrees of positive AoA. https://www.dropbox.com/s/5ceic1cs3lv1hhn/VigFigTwo.jpg?dl=0 Notice that the blue center of lift now moves almost exactly to the center of mass. Because the lift and mass are basically at the same point, now the elevon can use all of the control force it generates to maneuver the plane, because it's not wasting a lot force to keep the nose up. This also reduces your trim drag for level flight because the elevon can be in a neutral or near neutral position. The AoA of the canard contributes a lot to the forward movement of the center of lift. In the above linked diagram, the few degrees of AoA I put in accounts for almost half of the center of lift movement. The reason for this is that the AoA of the canards tilts their lift vector toward the plane's tail, so more of the canards' lift vector is aligned in a direction that counteracts the nose down moment of the delta wing. Here's a very exaggerated example https://www.dropbox.com/s/wbf670yxv35gpvj/VigFigFour.jpg?dl=0 Finally here's a diagram of canards by themselves, showing just the canards' center of lift in a Viggen-like configuration. https://www.dropbox.com/s/e9mexl6tzvnh5mb/VigFigThree.jpg?dl=0 It's possible that the canards on the Viggen do help prevent separation a bit, sort of like a leading edge slot, but they're very big and far enough ahead of the wing so that most of their effect is likely just from moving the center of lift to be closer to the center of mass. Anyhow, I hope the linked images help explain how canards help move center of lift around. Disclaimer, KSP uses a simplified aero model, and as such is not a good aircraft design tool. However, with the large catalog of parts and Center of Gravity, Thrust vector, and Center of Lift tools it's really great for throwing together a diagram for certain aspects of basic aerodynamic principles. Now if you excuse me, I think I'm going to go put landing gear on my diagram and see how it flies. :)

Nozzle design has a pretty big effect on ISP and thrust for rockets, that might be it. If I were going to guess I'd wonder if maybe the AIM - 7 and AIM 120 have more optimized convergent-divergent nozzles while the R-27 family has easier to manufacture convergent- divergent nozzles. I have no actual information on this, just speculation based on Soviet and US design philosophies.

Delta wings are known for being a good choice for high transonic and supersonic flight, especially at low altitudes. It's a wing that fits a low altitude high speed strike role very well. The hornet's LERX are vortex generators that significantly delay boundary layer separation over the interior portion of the wing at very high angles of attack. They also help with airflow past the vertical stabilizers at extreme AoA, which helps retain yaw and roll authority. The canards of the Viggen move the center of lift significantly forward on the aircraft, providing more stability and controllability in the pitch axis than a standard delta configuration with an aft balanced center of lift would have. By providing lift near the nose they also help improve stall behavior, but they're not really designed for increasing extreme AoA pitch control to the extent that the all moving canards of some Sukhois do. The Viggen's delta wing is geared to the main mission, the canards and the reversers are there to mitigate the drawbacks of the delta wing. Edit: It's a rather clever set of choices. SAAB got the high speed and low speed performance characteristics that they wanted with features that are mechanically simpler, lighter weight, and cheaper than the swing wings that other designers went with during that era when looking for planes with good handling across wide ranges of speed. It might be worth noting that while FBW systems and relaxed stability are geared in part toward gaining low speed control at high AoA, this mostly in the context of air combat. For the most part this isn't that useful for landing because extreme high alpha creates problems with visibility and tail strikes. It's nice to have for a panicky wave off, but if you're near max AoA on approach you're really hoping that the plane starts to pull up before the back end of the plane starts making horrible noises and throwing sparks as the runway starts grinding it off.

People might be talking past each other less if here if they knew the difference between efficiency- the amount of output b that you get per unit a. and effectiveness- The degree to which x performs task y. For flight performance: Chutes are more efficient, they give more braking performance per weight, volume, cost, maintenance hour. For landing roll and ground handling performance: Reversers are more effective at bringing a plane to a stop in the shortest distance without special airfield equipment or procedures. That's your tradeoff. Reversers are rare in fighters because flight performance is usually the top priority, and for a given amount of braking performance reversers are far too inefficient to compete with chutes, tailhooks, or getting a bulldozer and making the runway longer. If minimum landing roll and high sortie rate from that minimum landing roll field are mission critical though, the effectiveness of reversers can make them worthwhile despite their inefficiency. Ease of runway operation is also a significant benefit. Clearly the people who had to pick up the chutes from the Draken had some design input for the Viggen.;)

Well, if you had a pilot with a neurological disorder such that they couldn't feel acceleration or the pressure of the stick in different flight regimes then that pilot would be medically disqualified. What people really want for the Su-27 is an accelerometer warning of some sort that doesn't glue your eyes in the pit when they really need to be outside the pit. Really, this is a feature that both planes are missing, substitutes for the kinesthetic feedbacks a real plane would give. To max perform the plane this is just as much a problem for the Eagle as it is for the Flanker. The only difference is that for the Flanker if you get it wrong due to lack of kinesthetic feedback the worst case scenario is catastrophic airframe failure due to acceleration forces, whereas for the Eagle it's catastrophic airframe failure because you pissed away all your energy and took a R-73 up the tailpipe.