Vitormouraa

Centerline fuel tank? Airbrake doesn't work with it on the aircraft.

I don't know, you're the Viper expert here, so you tell me! :D :megalol:

Those are equipped with PW engines, look at the turkey feathers, they look flat. I saw someone say it's the Royal Netherlands Air Force.

@TOViper Thanks, I am aware of its meaning in the fluid dynamics. I was using the 'choke' as a typical/general term, not the one explained by the physics. Choke in the sense of "choke, stifle, asphyxiate, suffocate...", i.e; something is preventing the engine from doing its natural work of propelling the aircraft forward at Y or X speeds. Perhaps I shouldn't have used that word in this discussion unless I was using its technical meaning... :D

Look at the length of the afterburner plume, and all those shock diamonds. Very impressive!

Yeah I noticed how many times he trims the aircraft. I use a lot of trim when flying the Harrier as well.

I did some tests today, OATC was -3.1, and yep, maximum Mach number I was able to reach was 1.72, regardless of the altitude. It's quite interesting how the aircraft accelerates extremely quickly but all of the sudden stops at M 1.72. But I agree on the statement above, something is choking the engine. (It's been a few months since I flew the Viggen, so much fun flying it!)

Yes, and that makes sense. Bypass ratio is associated with the frontal area, when you're flying at very high speeds you want to minimize drag, so using a lower bypass ratio is a good idea, only at supersonic speeds, however. Bypass ratio is also associated with the propulsive efficiency, pretty much in all phases of the flight, where the aircraft is subsonic, the lack of a higher bypass ratio will affect mainly the fuel and thrust efficiencies. Increasing, however, the bypass ratio of an afterburning engine will also provide more oxygen to the combustion in the jet pipe, more unburnt, colder air will be feeding the afterburner, which greatly increases the thrust and efficiency of this engine. At the end of the day, it all comes down to the purpose of the engine, whether you'll be flying at high supersonic or subsonic speeds. A turbojet/low bypass turbofan will have good numbers at high speeds due to ram conditions, but if the aircraft is spending most of its time at subsonic speeds, using a low bypass engine might not be the best idea, perhaps increasing the bypass ratio will improve the performance of this aircraft at lower speeds, therefore it'll perform well in both regimes. There are a number of advantages and disadvantages for both designs.

Great video!

Try colder temperatures?

Although the RPM remains constant (RPM which was set by the pilot), the pitch does not. As the RPM approaches the RPM set by the pilot, the governor changes the pitch (increasing the area, which also increases thrust and drag) in order to keep a constant RPM. As to why pressure increases power, this has to do with the heat released by the combustion (oxygen and fuel), as you increase the pressure, the work output is increased, generally speaking. Hence the higher horsepower (work rate) created by the engine, so more pressure equals more horsepower available to the propeller. As mentioned above, one of the problems with an unducted propeller is that as you increase the RPM, depending on diameter, the tip tends to approach the speed of sound, which is a bad thing, but that's not the only way to increase thrust, fortunately, instead of increasing the speed, you can increase how much air the propeller "grabs" by changing the pitch angle.

According to this source, the D-30F6 has a bypass ratio of 0.57, which isn't that high, Viggen, for example, has a bypass ratio of 0.97 and F100-PW-229 is 0.36 according to Wiki. So I don't think it's that high? The D-21A1 though is different. It has a bypass ratio of 0.83.

The fan blades are strong enough to withstand bird strikes, in fact the fan is what 'protects' the core in case the engine ingests a bird or even FOD. Of course it will bend the blade and all that, but it shouldn't cause more issues than that, blade separation is usually much more complex, many of these cases the blades are involved in material fatigue, they have a very long background, sometimes a crack inside the fan structure which has increased over time until it reaches a point and it fails. We know that when a blade separation happens, the engine is completely destroyed, as we have seen in many engine tests. But they didn't know about the possibility of the blade striking the fuselage, if I remember correctly. Southwest was being investigated about the two CFM-56s that failed in flight, I think they had some issues with maintenance?

That has nothing to do with that... FYI this second case the engine fan failed and it hit the fuselage, it ended up killing a woman. This was a catastrophic failure, it was supposed to be a "contained failure" since the outer case is supposed to keep the fan inside the engine in case it fails/comes off from the N1 shaft, but that wasn't the case, the fan flew right at the fuselage. There was another case back in the 80s where the fan of a CFM-56 failed and the aircraft crashed because the pilot shut down the wrong engine, 47 people were killed. But see, fan failures have absolutely nothing to do with your first post...

Yep, I think it is. Tragic, it shouldn't happen. But this does not put the passengers at risk.

We did not have deferred shading back then. It's going to get better, I'm sure. ED is going to update the A-10C cockpit, no idea when though. :)

MiG-15 is great, a ton of fun when flying it. I was actually surprised when I flew it for the first time, it's very easy to fly, very smooth. Better than expected!

Nice! Thanks for sharing!

I LOL'd when reading this. That's hilarious! :D

Very cool! I'd love to see more posts by Yo-Yo on that matter.

Yes. Not sure how much air we are talking about here but anytime you bleed air from the engine you are essentially taking that air that would be used for combustion/cooling/thrust to cool down a component in the aircraft, which does not contribute to the thrust generated by the engines. Depending how much air is bled from the engine, you can even see an increase in engine temperature, like we see when we use an APU to start the engines, or when you use the crossbleed to start one of the main engines. But shutting off the bleed valves wouldn't make any difference when you're flying the aircraft I believe. Unless you measure everything precisely. But by "feel", no, you won't see any difference.

How much thrust do they produce? I was wondering, given the Mustang has a four bladed propeller while the Kurfurst has a three bladed propeller but both being driven with different horsepower ratings.

+1 for this!

Can't wait for the warbirds update!

Oh, here I am using the Blackbird as an example again :D I actually tried to look it up a bit more, initially, I thought the F-4 with its GE J79s (probably because of AgentJayZ videos - he has a ton of videos about nozzle actuators) used main fuel to control the variable nozzles, but my memory was wrong. J79 also uses the engine oil to actuate the primary and secondary nozzles, the same thing with the F110 and the F100 uses the bleed air as ShadowXP explained above. But yes the J58 on the incredible SR-71 used to use main fuel (JP-7) to actuate the nozzles. The engine had for actuators, the pressure was a function of engine speed (RPM), the signals were sent from the main fuel control system. JP-7 used to do so many things in the Blackbird, it's quite impressive.