SwingKid

Well, then I'm confused. In one message you tell me that I shoulnd't be using cross-section as a reference area, because I should be using wing planform instead. Now you say that in fact AFM doesn't use wing planform, but rather "each element has its own area." Ok, so what is the area used to calculated parasitic drag from the Su-25T main body? And what Cd, does it have? I'm not talking here about the induced drag from the wing, that varies with angle of attack - I'm talking about the parasitic form drag from the aircraft body, that generates zero lift. It seems to have Cd of about 0.05 in Flaming Cliffs, using the body's own cross-sectional area as a reference. Can you show a different calculation? I don't think that we can use the wing planform as a reference for parasitic drag Cd, because the wing planform induced drag changes rapidly with angle of attack, while parasitic body form drag doesn't. -SK

What in the... Which one is the REAL Crusty?! -SK

The ball shaped like a Su-25T, of course. We already know it falls faster than an artillery shell. :rolleyes: ;) -SK

If this is what you think is the Cd of an entire learjet, then what do you think is the Cd of its wing alone? -SK

Do you even know what Yo-yo is saying? I can't even tell if he disagrees. If he does, then I'm ready to take bets. ;) -SK

Yes, that's my question - does Flaming Cliffs AFM Su-25T drag include the aircraft body, or only its wing? -SK

Those aren't aircraft, those are wings. -SK

Indeed, as Yo-yo points out we have to be careful. In the link you provided, they use the wing plan area as a reference, not the cross-sectional area, so the Cd values are not compatible. My reason for using cross-sectional area is because at low angles of attack, the wing doesn't produce very much drag compared to the aircraft body. With respect, I'm not sure what you are saying here. Does AFM use the "standard area' for its calculations? i.e. - it includes the drag from the wings, but not the drag from the aircraft body? In that case, it might explain why the Su-25T seems "slippery." What do you mean, "my example"? My example is the Flaming Cliffs Su-25T. I would agree that it's wrong, and the real Cd should be much higher. Are you agreeing? -SK

The aerodynamic drag force may be calculated from the equation: Fd = Cd * 0.5 * p * V^2 * S where Fd is the drag force, Cd is the drag coefficient, p is the air density, V is the speed, and S is the cross-section area. Let's consider the Flaming Cliffs 20% fuel Su-25T in a 700 km/h, 30 degree dive at idle power (no speed brakes). The accelerating force due to gravity would be (sin(30) * 9.8 N/kg) = 4.9 N/kg. The aircraft's measured acceleration in the dive is only about 4.0 m/s^2, so the aerodynamic drag force must be (4.9-4.0) = 0.9 N/kg. For a total aircraft weight of 12254 kg, this gives us a drag force of about (0.9 * 12254) ~= 11028.6 N = Fd V = 700 km/h ~= 194.4 m/s, p ~= 1.225 kg/m^3, and from diagrams, I estimate the frontal cross-section area of a Su-25T to equal about S ~= 9 m^2. So the measured drag coefficient in Lock On is: Cd = Fd / (0.5 * p * V^2 * S) = (11028.6 N) / (0.5 * 1.225 kg/m^3 * (194.4 m/s)^2 * 9 m^3) Cd ~= 0.05 So, is the Flaming Cliffs Su-25T "slippery?" Consider: "a slippery road car has a Cd of about 0.32. A chunky one is 0.38." http://www.insideracingtechnology.com/tech102drag.htm The Flaming Cliffs Su-25T (Cd = 0.05) seems to be about 6 times more slippery, than a "slippery" road car (Cd = 0.32). So what's wrong, to say that it's "slippery?" -SK

For comparison, I used my "miniZAP" missile aerodynamics simulator: http://www.ecf.utoronto.ca/~pavacic/missiles/minizap.zip Instructions: (1) Click the drop-down "Missile Parameters" combo-box in the upper left (2) Select "105 mm Artillery Shell (test)" (3) In the middle column, in the "Intercept Controls" box, set "Launch Loft Angle" = -30 (4) Set "Launch Speed" = 700 km/h (5) Set "Launch Altitude" = 1000 m (6) Click "OK" button In the right column, under "Trajectory calculation", look down to the last few boxes. Acceleration is in two boxes near the bottom - "turning" acceleration and "linear" acceleration. Observe that the linear acceleration of this artillery shell is only 2.9 m/s2 Meanwhile, our lightly-loaded Su-25T in the same conditions is out-accelerating the artillery shell, at idle thrust, with 4 m/s2!! (reduced to a mere 2.5 m/s2 if we employ speedbrakes) Ok, I'm becoming even more persuaded, that the AFM Su-25(T) is too slippery. :( -SK

Well, I have to admit that my suspicions have been raised. Flying a minimum-fuel Su-25T in Flaming Cliffs with no payload at 1000 m altitude, I'm getting about 2.5 m/s2 acceleration in an idle-thrust 30 degree dive at 700 km/h with airbrakes, about 4 m/s2 without. Meanwhile Bedretdinov's book also claims the airbrakes "provided for steep dive without considerable acceleration at flight speeds of less than 700 km/h." A frictionless aircraft would only experience 4.9 m/s2 in a 30-degree dive. So, I'm not an aerodynamics expert, but considering that even an artillery shell can barely break the sound barrier in a 45-degree dive, I also have the sense that the Su-25(T) in Flaming Cliffs is "slippery" - with or without airbrakes. -SK

Adding more fuel to this fire: http://forum.lockon.ru/showthread.php?t=14854 :music_whistling: -SK

хорошие фотки http://tanksinmoscow.ru/index_02.htm -SK

IIRC, it took about 30 seconds to reach 350 KCAS with full burners, then another 24 (?) seconds to reach 32,000' at Mach 0.95. -SK

Good point - I tested only a clean F-15C with full fuel. I think someone did mention that the stores drag model may cause discrepancies. I purchased the F-15A/B/C/D Dash-1 from http://www.eflightmanuals.com -SK

Descriptions like this have burned me one too many times. When I took out the time-to-height charts for the F-15C from its Dash-1 flight manual and compared them to Lock On, they were dead on. To the second. Draw own conclusions. ;) :rolleyes: -SK

In Flaming Cliffs? I think it uses the Russian convention, which is opposite. -SK

Known error. After it was discovered, someone was afraid to fix it, in case there were missions or training files that used A-10 payloads with Mavs on these stations, that would stop working afterwards. Good question though, I hope it will be fixed in Black Shark. On a related topic, does anyone have photos of cluster bombs carried on TER? -SK

IMHO, this is because AF doesn't have aircraft from different countries for users to fly in multiplayer - i.e. practically no online dogfighting scene that I'm aware of, it's all co-op (read: "chickens" ;) ). If it did, such weapon options would lead to "cheating" complaints out the wazoo. Use or un-use of 27T on MiG-29A remains a mystery to me, there seem to be reasonable arguments both ways, so I trust in ED's superior Russian sources, to decide what is truth. It should be noted though that some MiG-29Gs are specially equipped to use wing drop tanks, so they aren't necessarily the same aircraft as "normal" MiG-29As. -SK

And now, for the spectacle you've all been waiting for... The two most powerful forces of the English forum, facing off in no-rules combat!! In this corner, weighing in at a combined 4674 lbs, the posters who complain every Friday, when new screenshots fail to be posted!! (wild boos) And in this corner, brandishing the dreaded plunger-arms of death, the posters who complain every Friday, that screenshots are showing the wrong stuff!! (wild boos) WHO WILL WIN?!? No one knows - but as long as Wags is around, bet on this - They'll better fight clean, or be thrown out of the ring!! -SK

Are you sure those are RWR antennas? #25 is the only Ka-50 that is equipped with experimental laser jammers, I think that might be what those are. -SK

Ha, ha. What I was thinking: "Oh sure, it's all sh*ts and giggles to them NOW - - until they find out after release, he was beta-testing Black Shark..." ;) -SK

One thing that is often missing in these discussions is the historical "lessons learned." If ED is to develop another carrier aircraft in the near future, how is it proposed to avoid what happened with Flanker 2.0 and 2.5? From my perspective, adding a carrier aircraft to ED's sims seems to have always coincided with a sharp drop in realism and/or sales of the product (Flanker 1.5->Flanker 2.0 Su-33, Flanker 2.0->Flanker 2.5 MiG-29K). I call it the "one-trick pony" for ED's self-destruction. In order to argue that that won't happen again, someone would need to identify the reasons why it happened in the first (and second) place. That could be a very interesting discussion/poll. -SK

If quality is not an issue and accuracy can wait, what's wrong with editing the MEInit.xml to say "humancockpit=yes"? Then the wait is over immediately, no? -SK

Hey! I don't know who you're lumping me with, but my tactics are 100% my own! :angry: Seriously, though. The trouble with giving a serious reply to an issue like this is that after you've explained everything, (a) knowing the reason isn't going to help the person from wanting whatever it is they want, and (b) even if the person you're writing to at least refrains from incessantly posting about their wish, very soon after, someone else will, and you'll have to explain it all over again. This is not a personal judgement against the originator of this topic. Beta testers and team members also have their own pet features that they simply cannot give up asking about, even when it's clear that they are out of scope for the current project. Yes, even me, I do it too. Enthusiasm is part of the nature of every enthusiast. The F/A-18 issue is one of the more pathogenic varieties. There is neither any immunization nor any cure for it, people just go on wanting and wishing and posting and polling no matter how many times it's explained. Any flight simulator is an immensely complex undertaking and there are many reasons why a flyable F/A-18 should wait for a future project - in this case the lack of documentation is only one of them. Merely mentioning this as a reason was Oleg's mistake, however, since he has only managed to fan the flames of the discussion by giving people something not to care about. The simple fact is that lack of consumer demand is NOT one of the reasons. Anyone who is willing to accept this without pouting already recognizes it on their own without an intelligent reply from ED or its testers (why else would we be getting the Ka-50 instead?), and for anyone who isn't - no intelligent reply would make a difference. It's unfortunate that this state of affairs comes across to some users as ED not caring what they think, but caring is a two-way street. ED faces their own challenges - e.g. finding manuals, that many of us seem not to care about. -SK