esb77

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.

Really this all argument boils down to, "which plane misbehaves less when I try to rip my stick out of it's base?" The crankiness is based on the premise that in DCS the F-15 is excessively idiot friendly while the Su-27 is a bitch that will kill you if you don't court it with champagne, caviar, and fine chocolate. There's a grain of truth to this. American engineers are a bit more inclined to pamper the end user (and also to assume that the end user is an incurable idiot). Mostly though, this is a matter of how the idiot resistant features in the respective planes work. In the F-15, it's largely based on the idea that if you try to tell the plane to do something excessively stupid, the plane is either strong enough to take it or just ignores your stupid inputs. This translates very well into a computer game. In the Su-27, if you start being excessively stupid in similar ways, the plane starts trying to swing a stick around pretty hard to get the pilot's attention. Specifically, the control stick. There is some limiting of execution of control inputs, but mostly it's a matter of alerting the pilot through the flight controls rather than overriding the pilot's control of the flight. This does not translate well into a purely software based representation. It would work much better as output for a force feedback stick coupled with a force feedback stick that has some pretty strong actuators. ED isn't being unfair to Flanker users, the Flanker users are just failing to upgrade their input hardware to be fully compatible with a Flanker simulation. I'm saying that from a position of the Flanker being my favorite plane (at least until the Hornet comes out). If everyone built and flew from a full fidelity pit with a properly calibrated FFB stick, I don't think there would be much griping about the Flanker being unruly around the edges of its envelope. The flight models are a continuous WIP for ALL the modules, and probably everyone posting in this thread knows that. For the simulation improvement, sure the F-15 model might be able to use a more realistic damage model for g overstress, but not nearly as much as the cranky Su-27 users need to get better input hardware. The Flanker communicates to the pilot by swinging a stick at them, if your stick doesn't do that then if you want a better Flanker simulation then you need a more lively stick.

I just flew the mission in the latest version of DCS 1.5, and aside from a spectacularly bad approach and, well I'm not sure if I should call it a crash or a landing (crash-landing maybe), there were no issues. I'm definitely out of practice for a crosswind landing where the crosswind component is more than 40 km/h. A few comments on the mission in its current state: Some of the altitude changes between waypoints were insane, well outside of what the aircraft is capable of. That said, as pilot, your responsibility is to review the flight plan before takeoff and if the waypoint locations or altitudes or speeds are clearly crazy you should either edit them or plan to ignore them. The HUD steering circle was all over the place, especially at long distances. I ignored it and flew the waypoints by following the HSI. Blindly following the steering circle would have produced poor to disastrous results. There was only one "fly into the mountain" spot that I saw, and I was a bit off of the course line so that may have been my error. There were however 5 or 6 places where if you don't anticipate the turn you'll get awfully close to the hillsides in the river valley, especially if you don't know how to make a coordinated turn. Some of those turns are also 60 degrees or so of bank if you don't want to get close to the hills. For the AI and autopilot in missions you can set waypoints to "fly over" or "turn before" and it looked to me like these were supposed to be "turn before" based on their locations in the river valley. The smart option is to just ignore the waypoints beyond "is this the right river" and fly down the valley VFR manually cycling the waypoints if you don't get close enough to trigger them. If flying a Su-25 and the tower tells you that there is a 13 m/s crosswind on the runway it would be a good idea to divert to a field where the wind direction and runway direction are not almost perpendicular to each other, if you have enough fuel. There was no fire but I trashed the tires and the gear and ran off the runway by about 400 m. I should have at the very least done a go around, but really I should have diverted to Mineralnye. So my advice is: Look over the flight plan before you fly. If you see something that looks dangerous or foolish, change the plan. This is a chief responsibility of a pilot. If instruments are telling you do things that seem foolish, cross check with other instruments and use your judgement. Just because the HUD steering circle indicates that you should fly into the side of a mountain does not mean that it is really a good idea. (Note, for night and IFR flight conditions you really need to know and check your flight plan, when instruments are all you have, you need to be sure that your waypoints don't lead to controlled flight into terrain). Check the waypoint number in the HUD and in the counter window on the HSI, if the automatic turnover didn't trigger because you didn't get close enough to the set waypoint because you were flying a safer course then just manually cycle to the next waypoint. Right Ctrl + `. The pilot's job is to be intelligent and spot potential problems long before they happen so that they can be completely avoided. Do that, and this mission is quite easy.

To perform CCIP bombing the impact point needs to be within the HUD. In general in the Russian FC3 aircraft you want to be at about 3000 m AGL, 450 to 600 km/h airspeed, and then dive at the target with low throttle at a dive angle of at least 30 degrees. Ideally release and pull up by around 1200 m AGL to avoid all danger of self frag or controlled flight into terrain. You can push it a bit lower with a smaller bomb like a FAB 100. For low level CCIP bombing you'd either be using the submunition canisters or retarded bombs. For those the key is high speed and low altitude. On the order of 750 to 800 km/h and 100 to 200 m AGL. For the retarded bombs it's important to factor in wind direction, as they can drift a surprising distance on the way down. You might try the tutorial missions for the Su-25T and the Su - 27. I know the Su - 25 ones cover CCIP bombing, and I think the Su- 27 ones do as well.

Keep in mind that you are creating an illusion of level flight. In reality, if you roll 90 degrees you're basically skydiving while wearing an airplane. You and the airplane are in freefall, and preserving the illusion doesn't last long. In the video he only holds a full edge on position for 4 or 4.5 seconds. There are a bunch of things that contribute to maintaining the illusion from the airshow audience viewpoint. Lack of visual references. They're looking up, ideally enough so that any ground references are in their peripheral vision. This makes it hard to see that the plane is not truly flying in a straight and level path. Viewing angle. Again, being high enough in the field of view gives you an edge. By forcing the view to be at an angle from below, the vertical rise and fall of the airplane creates less angular displacement for a ground observer than would be apparent to an aircraft flying straight level, and in line abreast formation with you. Starting with a positive vertical velocity. If you're climbing at 5 m/s when you roll fully 90 degrees, then it's going to take a second or so before your vertical velocity drops to zero and you start falling. Assuming of course that you make your roll in a way that doesn't bleed off that vertical velocity. Slight upward yaw. The side of the plane will generate a slight amount of lift this way and your engine thrust vector will also have a slight upward component. You'll still be in freefall, probably faster than a skydiver in a wingsuit, but every bit helps. Not really rolling the full 90 degrees. Keep it at 80 degrees and pull a slight turn, and you'll get a bit of upward lift, but it will be very hard for ground viewers to detect this. Short duration. Typically it is only done for a few seconds. The one in the video was pretty long, and it lasted about 4.5 seconds. At the end of the day, level flight while rolled 90 degrees is an illusion. Seventy million dollars is not enough to buy an exemption from the laws of physics. Edit: Forgot to mention that extra altitude also helps, the farther up you are the longer you can fall before they start to notice. If you just want edge flight, and don't care about pretending to be in level flight, then just start at higher altitude, keep airspeed up, and hope your fuel system pickups are still submerged. If you're having trouble with not enough yaw to keep the nose level or slightly up you can on twin engine planes throttle down the upward engine to give it a bit more nose up yaw.

To expand a little bit on visual approaches, try setting up a good instrument approach at a field with the HUD ILS. If you get on slope and stabilized nicely, either pause the game, or take a screenshot. Now you have a pretty good sight picture. What you want to do, is try to pick out the point on the runway where you'd like to touch down. At 15 km, this may be hard to see, and you can just substitute the near end of the runway. Now look at your cockpit, and find a feature like a bolt, a scratch, a cable, or some other fixed part of the cockpit that lines up with where the touchdown point appears on the HUD/Canopy. Memorize this feature. Then in the future, when you want to be approximately on slope for a visual approach use 1000m AGL(runway) at 15 km out as a starting point, then line up your memorized marker with your desired touchdown point, and keep it there as you fly in. You can download a free copy of the FAA basic airmanship manual, and read up on the correct procedures for landing a fixed wing aircraft. It goes into more detail. For that matter, the manual has a lot of info on good piloting in general, and includes quite a few diagrams. It's surprisingly well written for a government document.

I forget the full list of conditions for which the IR scanner automatically turns on/off, but if you see the IR targeting information on the HUD, then yes. The difference between the radar and IR modes on the HUD are fairly small, but at the least you should have a 2-3 letter code indicating that your EOS system is active, and I think that you'll probably loose range information on the HUD. At least if you only have your own aircraft's radar to work with. It gets a bit more complicated if you have AWACS support or datalink from other fighters, because they can feed you range data. I can't remember if when you have AWACs the range comes up on the HUD or just on the HDD. We should probably both go read the manual pages about that.:) There are differences, but they're small and easy to forget if you don't practice on regular basis. If I want to be sure I'll be lazy and turn off everything, and then turn on an EOS only mode, if I reacquire then I know it's a good EOS signature. That's not the best way to do it though.