Vitormouraa

HWasp, I was able to match everything you said. At least in terms of Load-factor. Check out the attachments below. Conditions: Standard day; 21,400 kg total, 3900 kg of fuel (41%). Average height 130 meters above the ground. One thing; at 600km/h IAS I was able to reach 7G instead of 6G. I should have used Ground speed as reference :doh: :doh: I also forgot the fact that I can use infobar in the cockpit :D

Thank you guys. Looking forward to seeing what you have for us once you get back home. I'm here to learn, as I am not good at pointing out what's wrong with the FM or anything about aerodynamics. I find this discussion interesting and I'm very interested in seeing the DCS FM compared to the real thing.

Let's say that's correct, if the AoA/G Limiter won't give you an extra maneuverability, what's the use of it?

Yeah you're not going very far. But if you avoid using AB all the time and fly at 15k or so, you can increase your range a bit. I guess we will find out if that's a good loadout or not. We could also use two fuel tanks, one on the centerline and on the inner pylon. Hornets seem to like asymmetrical loadouts.

In case you have a text in Russian, post it right here and I'll try to get a translation for you.

:megalol:

That 10 AMRAAMs loadout is very draggy, breaking sound barrier might be a bit difficult in case you want to do that for whatever reason of course :)

Interesting how people see different colors, I see yellow :)

Not quite true; Mavericks lock onto objects, and not contrast. That's why you can't lock up a tank wreck after destroying it. That's why you can't lock onto shadows, and other things. That's in DCS of course, in real life you'd be correct.

Still, haven't seen anyone pointing out the Eagle or Flanker's problems/issues with real-life performance charts. Article or pilots reports don't have much value I believe. ED isn't going to change anything in the FM because someone said it was wrong. It's important to make these affirmations based on real data, and not articles or theories taken from the internet.

No problem, again I don't have any charts showing what I said above, but that's how turbojets and turbofans behave, generally speaking. But you can take a look at the F-15 and see how the FF varies. You can pretty much apply that to the M-2000C, except the fuel flow number, but the way it varies should be similar.

The fuel consumption and speed relations are quite wrong in the M-2000C. Your fuel flow (FF) will increase with forward speed, due to ram effect. The engine needs to compensate for the incoming air, which doesn't necessarily mean you're making more thrust, in fact it's quite the opposite until certain speeds depending on inlet system. For colder temperatures, the engine has to trim/adjust the fuel flow because the turbine requires more horsepower to drive the compressor, so the fuel flow is increased. But as I said, your fuel consumption will always increase with speed, it should decrease with altitude due to the air inlet density decreasing. However, the fuel flow and speed relations aren't correct, the FF should be greater at high speeds. I was flying at 924 kts at 35,000 ft with a FF of 174 kg/m, this number should be twice I believe, again I don't have any docs on the M53 engine, I'm just guessing here but it should be much, much higher. And little detail that proves the Mach and FF relation are wrong, this number stayed the same from 600 kts until 900 (Over Mach 2.1).

I have to say I got very confused about the leading edge devices after watching this thread so many times, one says one thing, and the other says it's wrong :D Here are two examples from a book I have called "Aerodynamics for naval aviators".

Why would you use that scenario for comparison? the Eagle with 1% fuel isn't realistic. It would burn this fuel in less than 5 seconds. Eagle can't be flown with 1% of fuel in real life, if you think DCS FM is wrong, and you like to compare it with real life, you should at least use a realistic loadout.

That's a very cute engine! :D

Jacobs, I'll try to explain the basics of it. Maybe I'll be a bit too technical, but that's me :D Short answer: The turbine is responsible for extracting the kinetic energy of the gases coming out of the combustion chamber. This stream of airflow and gases, at a very high temperature, make the turbine spin. Just like your fan when the wind is blowing against it. And since the turbine is connected to the compressor rotor thru a shaft, the turbines are keeping the compressor working, so the compressor pulls the air, air is compressed, then ignited in the combustion chamber, they release a lot of energy and they pass thru the turbine rotors, around 2/3s of this energy in a turbojet is used to drive the compressor, and the rest goes into the atmosphere and pushes the aircraft forward. So imagine if you could blow enough air onto the turbine rotor, the entire engine would spin. Compressor, accessory gearbox, everything. Technical answer: We could say that a turbine engine is composed of five parts, the compressor, diffuser, combustors, turbines, and nozzle. The compressor is responsible for getting the air and rising its pressure with the minimum temperature possible. Compressor pulls the air from the atmosphere, increases the velocity of the air, and then the air is diffused by the stator vanes, that's what compresses the air in the engine, it's not the compressor rotor. Now that we have this air under pressure, we need to send this air to the combustors, where the air and fuel mixture are going to be ignited, just like the fuel and gasoline in a reciprocating engine. Pressure and temperature are EXTREMELY important here because they are directly related to energy expansion, so higher the pressure and higher the temperature in the combustion chamber, more energy is released for the same amount of fuel. Therefore more energy can be extracted from the gases, and more energy can be used to produce thrust. After the air is ignited in the combustion chamber, the combustors have the hard, and complicated job of releasing all this energy into the next stage, in a stable stream of airflow, at a temperature that is not going to melt the turbines. But before the turbines, the hot gases are going to pass thru the turbine nozzles, which are stator vanes used, not to compress the air, but the opposite, to increase their velocity and guide the flow at the correct angle onto the turbine blades. So the hot gases go thru the turbine nozzle, velocity is increased a bit, they turn the turbines that drive the compressor and keeps the cycle working. And finally, the nozzle works the same way as the turbine nozzle, it basically uses a specific geometry in order to increase the velocity of the gases coming out of the exhaust. That would be Bernoulli's principles. Take a look at De Laval Nozzle on the internet. I hope that helps!

Drag? yes, it would. Weight? not really. Weight or actually mass would increase the inertia of your aircraft, in other words, how long it takes to reach 530km/h (just an example). One little detail though, heavier the aircraft, more lift you need in order to maintain a constant altitude, and you would do that with AoA, and higher the AoA, more induced drag you would have (drag due to lift). But in this case, I don't think it's a big deal. Hummingbird said he was using operational loadouts anyway.

I hope we will be able to see birds on radar then, before they strike us on take-off :D

Alfa, You're correct! Yesterday I was reading the NATOPs manual and it says that the AMPCD can display anything, except the A/G radar screen.

Yes sir! This is in fact getting a bit off topic. Please take a look at my Jet engine thread if you want to discuss the subject!

Yup, that's really awesome. I was looking for a chart like that for the Eagle. Thanks for sharing! You should see the Blackbird, the pressure in psi at 85,000 ft is around 0.3 and the inlet system can rise that all the way up to 14, 16 psi! With forward speed and ram recovery.

I read the entire thread and I am sure this is well explained but I just wanted to explain a few things if you guys don't mind. One thing you should keep in mind is the fact that on the testbench, the engines have a bellmounth inlet installed. Which prevents inlet depression. And improves the airflow to the engine. As for the speed and thrust relation, yes the engine loses thrust because of the difference between the V1 and V2 velocities. V1 is the velocity at which the air enters the engine, and V2 is the exhaust gas velocity. If the values are the same, no thrust can be made. And that's called Ram drag. Ram drag is introduced when the aircraft has forward speed. On take-off this is generally ignored though, so we can use gross thrust in that case. Not the data from the testbench though. Formula for this would be Ms (V2 - V1) / g So let's say an engine has a mass flow of 250 lbs/s and the exhaust gas velocity is 1,800, so using the formula above 250*1,800= 450,000/32.2= 13,975 we can see that the gross thrust is 13,975 lbs of thrust. That would be the engine on the ground, standard day conditions. No forward speed. When you add forward speed (V1) to this equation, the thrust decreases because the difference between V1 and V2 is reduced. And now, it's called Net thrust. So let's say the same aircraft is flying at 450 miles per hour (660 ft/s). Since the aircraft is flying at 660 ft/s, we can add this V1 number to the equation, which is 250 (1,800 - 660) / 32.2. The V2 is subtracted from the V1, so again, the difference between V1 and V2 is greatly reduced. Considering that the mass flow and exhaust gas velocity stay the same (which they won't in this case due to ram/pressure recovery), we can see that the thrust being developed is 8,850 lbs of thrust. A lot less compared to the engine running on the ground. This is a rule for most of the subsonic aircraft, at sonic and supersonic speeds, these aircraft generally have a complex inlet system which makes a great use of the Ram effect, so with forward speed, it's possible that the aircraft will eventually overcome this negative effect, which is the ram drag. For instance, the Viggen engine at Mach 1.1 produces around 164kN, 36,000 lbs of thrust. On the ground it produces 115kN (25,853). So forward speed can either be a good or bad thing for the airframe. It all depends on what the aircraft needs. Heatblur recently released an update showing the progress on the F110-GE-400 engines, and one of the graphs shows the engine making 133kN at Mach 0.9. That's probably the highest thrust this engine can make though, from that point, thrust is going to decrease, because of the inlet efficiency. Mach 0.9 is probably the optimum speed for the Tomcat, in terms of thrust at least. Keep in mind that Ram drag wasn't modeled here. With that said, gross thrust and net thrust are completely different. So they can't be compared, you shouldn't say that the Eagle produces the same thrust as the engine on the testbench. Because it doesn't. Unless the aircraft is flying at a specific speed where the Ram recovery is great enough that the engine can recover some of that thrust. Unless you have an inlet system that is capable of diffusing the supersonic air (which increases static pressure), you won't be able to get that thrust back. With no augmentation obviously. :) About the thrust being lost because of the intake ramps and all that stuff, let's use the MiG-21 as an example, the MiG-21 has a moveable spike in the nose, and a 'tube' that extends all the way back to the engine, throughout the fuselage. It's quite long, and not quite efficient, efficiency is lost due to the air viscosity and friction between the air and the walls of the tube. So you could say that these engines on the testbench aren't suffering from that, on the contrary, they have a device called bellmounth inlet which helps the engine as I said above.

I like this thread, I'm learning quite a bit. So the Leading-edge flaps on the Su-27 are meant to generate lift and not to increase the critical AoA of the wing?

There may be some exceptions, but overall, yes the amount of detail is still insane for each, every module. As I said, HB is putting their money on new technologies, which is great. But that's a trend for all third parties, it's up to them. There are companies that can't even finish their modules, imagine doing what ED, BST and HB do. :)

This is nothing new. All full fidelity modules have this kind of detail. HB is, in fact, using new technologies to develop the virtual engines, just like Eagle Dynamics, but with third-party tools. The amount of effort and knowledge put into DCS modules are insane. This argument is valid for ALL modules :) Sure, we are seeing things that we haven't seen in the past or things that we don't have available in the sim, such as new engine modeling/engine dynamics, new radar modeling and others, but as I said, all modules have an insane amount details. The difference between HB and other devs is that they are letting you know what's going on behind the scenes. There are SO many things that you don't know about other modules that would make you cry. In a good way of course. :D