Jump to content

Fox One

Members
  • Posts

    431
  • Joined

  • Last visited

  • Days Won

    2

About Fox One

  • Birthday 12/25/1977

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Fox One

    Radar functions

    Here is another very short look at the real radar display: There is clearly a lot of room for improvement for the clutter, but Aerges are probably well aware of this.
  2. Phantom, LOL :megalol: The Phantom is "eagerly awaited" by a small minority. The vast majority would be DEEPLY DISAPPOINTED if the new "hot" module from ED is gonna be any old aircraft. Personally I would also be very surprised if it's a "full module" of an existing FC3 aircraft like F-15C. Here is what Matt Wagner said in October 2019 "Is there hope for an F-4 Phantom? If so, would it be off the mark wishing that the developer is Heatblur using the multi-crew experience and technology created building the Tomcat? The Phantom is such a legendary aircraft that we will certainly simulate it. For now, we already have another aircraft (an eagerly awaited one) to work on after the Viper." https://www.mudspike.com/mudspike-ama-with-eagle-dynamics-senior-producer-matt-wagner/ IMHO it is clearly implied it's an aircraft, not helicopter. After reading this forum for more than 15 years, I'm convinced the majority are eagerly awaiting the newest and bestest. Rafale, Typhoon, Su-35 - that's the kind of aircraft the majority are eagerly awaiting. I say it's Rafale
  3. Thank you for giving exactly the answer I was expecting :D In my second track (test2a) where I land with 30% fuel when the speed is 135kts and the inverted T is perfectly on the horizon line, the longitudinal G is -0.45. In the real aircraft in the video it is -0.15 In simulator, if you lower the nose gear to the runway, at 135kts the longitudinal G is -0.1 This deceleration is of course caused by aerodynamic drag and wheels drag. But I am generous and let's pretend the aerodynamic drag is zero and this -0.1 is entirely wheel drag. If you remove this -0.1 from the deceleration of -0.45 that is recorded at 135kts, you still have a deceleration of -0.35 that is more than double the value from the real aircraft. And all of this is ignoring the fact that when the real aircraft is aerobraking at 135kts at 13 deg AOA most of the aircraft weight is still supported by wing lift. Therefore, the load on the main wheels is fairly low and so the wheel drag is quite low. But I was being generous again... I am sorry to say, but it looks like I am wasting my time trying to tell you anything. You have decided in your mind that the simulator is accurate and you will fight to death anyone who sais otherwise.
  4. At the end of the video the pilot lands and performs aerobraking. As can be seen, the speed is decreasing very very slowly. Deceleration from 140 to 110 kts takes about 12.5 seconds. During this time the longitudinal G is between -0.15 and -0.13. Let's see how the simulator compares to that. In the attached tracks I deliberately land at high speed, so that when the speed drops to 140 kts I am already stabilized with the inverted T on the horizon line (or close to) and the engine is already in idle. In track 1a I land with 100% fuel and deceleration from 140 to 110 kts takes 5.3 seconds. That is 2.35 times less than it takes for the real aircraft in the video. Longitudinal G is, as expected, more than double the value from the real aircraft. In track 2a I land with 30% fuel and deceleration from 140 to 110 kts takes 4.6 seconds. That is 2.71 times less than it takes for the real aircraft in the video. Longitudinal G is, as expected, more than double the value from the real aircraft. The aircraft in simulator decelerates so fast not because the wheel drag is too high or the engine idle thrust is too low (although the wheel drag might be slightly too high). These are relatively minor forces compared to airframe drag. It decelerates so fast because of aerodynamic drag that is way waaaaay too high. This is obvious when the nose wheel is lowered to the runway - the longitudinal G decreases proportionally with lowering of the AOA. When aerobraking at 13 deg AOA and there is still enough speed, if you increase the AOA by as little as 1-1.5deg (not demonstrated in the video, but anyone can try) the longitudinal G raises to the amusing value of about -0.5 (for comparison, during takeoff with 100% fuel and no stores, the longitudinal G is about 0.68 ). This test for deceleration during aerobraking is not revealing some minor unimportant inaccuracy that manifests itself only on aerobraking and everything else is fine. Is the same very high drag at an AOA of 13 deg also acting during flight? You bet it is!!! Now if you go back to post #34 and read about the turning test described there, you will understand perfectly why the DCS M2000C results are in a completely different league from the other planes tested F-18 and F-16 (result for F-15 test too, in post #38 ). I performed a perfectly horizontal slow speed flight test with the M2000C (no track attached). For an AOA of 29 deg the speed was 92 kts and the required engine rpm was 88%. IMO the numbers are not bad. I also think the drag at a low AOA of 2-3 deg is generally adequate. In conclusion. The drag at low AOA is OK. Then increasing the AOA the drag gets too high and at some mid-range AOA, drag is way too high. You don't have to be a mathematician to see from the aerobraking test that at 13 deg AOA the drag is not off by some 10%. It is much much more. Increasing further the AOA from this mid-range AOA, the difference in drag between simulator and real aircraft definitely gets smaller and at max AOA of 29 deg drag is, let's say credible. I don't care how the M2000C simulator compares with a turn performance diagram that you know very well it is an estimation. All I care about are demonstrable facts. The drag being much too high at an AOA of 13 deg is a demonstrable fact. Even if that well known turn performance diagram was from the real Mirage 2000C flight manual, and the simulator aircraft would perform exactly like that, that still wouldn't change the fact that at an AOA of 13 deg the drag in simulator is much too high. If the real aircraft in a sustained turn where the AOA is 13 deg (at whatever speed that might be) performes similarly with DCS M2000C simulator, this means in simulator besides the drag at 13 deg AOA being too high, the thrust is also too high. test1a.trk test2a.trk
  5. It doesn't generates more drag at "low speeds". It generates much much more drag at an AOA of 10 to 12 deg. I don't know what the idle thrust of Mirage 2000 engine is and I bet you also don't know. Two examples. MiG-29 engine RD-33 has an static idle thrust of 180Kgf (source, flight manual). Su-27 engine AL-31F has an static idle thrust of 250Kgf (source, technical description manual). Let's put Mirage's engine idle thrust somewhere in between, let's say 200Kgf. At 300kts and 10deg AOA, Mirage 2000's total drag is of SEVERAL TONS. 200Kgf of idle thrust is not gonna make much of a difference. Besides, you don't know (and I don't know) how Mirage's engine idle thrust changes with flight conditions. For example, in MiG-29's case the static idle thrust value quickly decreases with speed and at a low M number of about 0.16-0.17 it is zero, then increasing the speed further it gets a negative value of about -270Kgf at an M number of about 0.57 (source, MiG-29 practical aerodynamics manual). So in the test I made here, in the 300-150kts speed range, Mirage's engine idle thrust might be small positive, might be small negative. But anyway it is negligibly small compared with the drag. So please keep the idle thrust out of this discussion as this doesn't have a considerable effect.
  6. The please repeat the test on your own if you can fly much smoother/precise, and post the track here. Let's see if you will get vastly different results.
  7. What happens, as I don't have the Viggen module?
  8. I just did some tests, tracks attached. With the M2000, F-18 and F-16, with 50% fuel, standard conditions, altitude 1500ft, I perform horizontal flight with 150kts speed. The M2000 needs an AOA of 12.6 deg The F-18 needs an AOA of 11 deg The F-16 needs an AOA of 14 deg How does this fits with your theory? In my opinion, you are generally right. However if that's the case (like the M2000 AOA in the test is 1.6 deg higher than on F-18 ) the difference is small. If the difference was big they would have designed the Mirage in a different way ;) test2000.trk test18.trk test16.trk
  9. The Mirage lands with 14 deg AOA because it can't afford to deflect down 45 deg the ENTIRE trailing edge control surfaces like the Hornet does. It is basically like a plane that lands with "flaps up", and the 14 deg AOA approach is to keep the speed in a reasonably low range. Try to land the Hornet with flaps UP and 8.1 deg AOA on approach and see what kind of speeds you get... You truly don't understand at all the turn test and its purpose. The purpose of the test is to see how quickly the speed decreases from 300 to 150 kts if the engine is in idle (almost zero thrust contribution). This removes engine thrust from the equation and shows only the airframe efficiency. The turn itself is performed to KEEP THE ALTITUDE CONSTANT. If the altitude was not constant the speed would decrease faster or slower if the aircraft was climbing or descending, and this would make analysis and comparison more complicated. The altitude of the test is what you see on the HUD and is held constant. The G or bank angle of the turn doesn't matter. It is what it is. What is held constant is the altitude and AOA. So the test shows how quickly the aircraft at a constant altitude and close to constant (10 to 12 deg AOA) will decelerate from 300 to 150 kts with no thrust. The result is compared as the deg the aircraft is able to turn. It could have been time very well. One aircraft performs much much worse than all the others. Which is obviously not plausible.
  10. ^^^ I don't know best. I know when something is wrong by so much, that is obviously wrong ;)
  11. Hi =DECOY=, I am not a Mirage pilot. But I am convinced that by carefully studying what is out there and using a little "engineering common sense" the flight model can be improved A LOT. I know jojo is one of the knowledgeable guys on this forum and usually I read his posts. But I am quite disappointed that he is not exactly objective on anything regarding the M2000 simulator.
  12. silly... Because somebody shot down somebody else this somehow makes what I said wrong? On what logic? I also did the turning test described in my previous post in the F-15, that is classified as an aircraft with a "cropped delta wing". It turned 200 deg. But unlike the Mirage 2000, the F-15 is not a relaxed static stability aircraft. It is a conventional aircraft, and in flight its horizontal tail is producing a downward lift force, and this downward (adverse to the wing lift) lift force also generates drag. On Mirage the entire wing is producing an upward lifting force. The Mirage is also a delta wing aircraft, but conceptually superior to the F-15. It also has leading edge slats so the wing has "variable polar" characteristics, it continuously moves the slats and adapts to the existing AOA to optimize its characteristics, something the F-15 doesn't do at all. So the Mirage compared with the F-15 has A LOT OF STUFF in its favor. Its only minus is a smaller thrust/weight ratio. So the results of the turning test are for F-15, F-16 and F-18 are 200, 200 and 210 deg. Do you think it is a coincidence they are practically similar? It's not. This is what a high performance aircraft of 4th generation would behave like, of course the numbers are similar. On the other hand the result of the turning test for the Mirage 2000 is 95 deg. Perhaps you think it differs so much from the F-15, F-16 and F-18 because the Mirage 2000 is not a " high performance aircraft of 4th generation ". No. I'll explain to you where the very big difference comes from. The difference is explained by the fact that the F-15, F-16 and F-18 flight models were made by competent aviation engineers. The Mirage 2000 flight model was made by... a guy with different qualities ;) As I already said, the Mirage 2000 flight model is not a little off. A little off would be fine and I would have no criticism, as you said no simulator is perfect. But it is completely off, as this simple test proves. You just need a little common sense to see it, but you know what they say, common sense is not that common... I would like to hear from you a comment about the fact that on landing during aerobraking an increase in AOA of only 1.5-2 deg would instantly DOUBLE the longitudinal G. In you opinion this makes sense and is plausible, correct? This has nothing to do with what I am explaining here. I haven't said anything about the Mirage not producing sufficient lift, have I? What I am criticizing here is the drag that is excessive. The Mirage simulator "lift-producing abilities" I think are actually pretty close to the real aircraft and I actually have no criticism in this regard. In simulator the aircraft can generate very high pitch rates that look to me very similar with what can be seen from the well known Mirage aerobatics HUD video. Because it can produce plenty of lift, of course it can perform maneuvers with a small radius, like the split-s you described. I haven't said the Mirage flight model is crap. Or the Mirage module in its entirety is crap. There is plenty of good stuff in it, like what I said just above. Do you think I am criticizing it because I don't have anything more interesting to do? I would like very much to have an accurate flight model on this interesting aircraft. I paid 60 bucks for it, just like you. Personally, I think you are blinded by your love for this aircraft. It is well known that when you are blinded by love, you are completely unable to view the object of your love in a critical way...
  13. You don't say... Attached is a track with a test I performed with the Mirage. With 50% fuel I accelerate to 360Kts, then I reduce throttle to idle. When speed drops to 300 I start a horizontal turn keeping the AOA between 10 and 12 deg, and I turn until the speed decreases to 150kts. The aircraft will turn approximately 95 deg. I performed similar tests with F-18 and F-16. Until the speed decreases to 150kts the F-16 will turn about 200 deg, the F-18 about 210 deg. If the Mirage 2000 would really behave like that IRL it would be a very poor aircraft. 10 to 12 deg is not a large AOA, in fact most supersonic aircraft have the optimum maneuvering AOA in this range, perhaps even slightly higher. The difference in this test between M2000 and the F-16 and F-18 is obviously brutally large. You don't have to be a scientist to figure in the M2000 the lift/drag ratio is really off as soon as you start to increase a bit the AOA. I mean really really off, not 10%. Next in the test I perform a landing and I aerobrake the aircraft with the inverted T on horizon line. In the real aircraft, from a HUD video during aerobraking the longitudinal G is -0.15...-0.13 In simulator it is almost double that value. A video with a Mirage aerobraking for 14 seconds (and still going when filming stops): Can you do that in DCS? Then in the test I take off again and made another landing. During aerobraking I perform some small stick pulls, increasing the AOA with 1.5 to 2 deg. Look at the longitudinal G - with an AOA increase of just 1.5 to 2 deg in a fraction of a second the longitudinal G practically doubles!!! There is no need to perform any other test to realize the M2000 flight model is not bad. It is amusingly bad. In the first turning test I wouldn't be surprised if an F-104 would perform better that the M2000. In fact, I also performed the turning test in the F-5, but with 100% fuel and the LE/TE flaps "UP" to make its small wing even less efficient at 10-12 deg AOA. The F-5 turned about 140 deg in the test. Gee, I never knew the Mirage 2000 is so aerodynamically inefficient at an AOA of just 10-12deg! The French aerodynamicists are the worst in the world! Who would have thought!!! It blows my mind how the author of the Mirage flight model, who if I'm not mistaken is an aeronautical engineer, doesn't see all of this! This is elementary stuff and elementary observations, it's not rocket science. "This is a French Air Force-approved simulator" is a nice trick that probably works on naive and uninformed people. Then convince a French Air Force pilot to register on the forum and say the real aircraft behaves just like the simulator in the tests described above and he really sees no problem at all. Go ahead. I'm serious. Get a real pilot here to tell everybody how the real aircraft would behave in the tests described here. I know a major revision of the avionics is in the works. Even if they get that as good a a real military simulator, with the current flight model it would have no value. Any moment jojo will appear to "get things straight" and "defend the module" :D Cause we all know its flight model was made by NASA scientists and is close to perfection... z.trk
  14. For me landing with full flaps after main wheels touchdown even with full aft stick the nose wheel touches the runway in 2-3 sec (even at minimum vertical speed at touchdown). Can you keep the nose wheel up longer? In the first video in this thread it's 6 seconds. The airbrake I don't think it has any nose-up pitch effect in sim.
  15. The flight manual says aerodynamic braking is not recommended. It doesn't say aerodynamic braking is not possible, even pulling the stick fully aft. The first video link in this thread clearly shows IRL aerodynamic braking can be done nicely. However in DCS when landing with full flaps aerodynamic braking is not possible, even if you quickly pull the stick fully aft. Just not possible, even if you land with close to zero fuel and remove gun ammo. Obviously, in DCS F/A-18 there is still some stuff that is not accurate in the flight model. However in the sim aerodynamic braking is possible if you land with HALF flaps. So the error in the flight model might be flaps related. With full flaps some data in the flight model is probably incorrect.
×
×
  • Create New...