Why didn’t you address any of the data he sent as attachments?
Why don’t you provide your own evidence if you’re so sure he’s right? I provided mine last night, off GE’s website. Have a look for yourself if you don’t believe me.
What has this to do with you not addressing his data in any way? Where did i say he is right? I asked you about not addressing his data. I didn’t say he is right.
It has to do with the fact you can’t comprehend that you know… he could just be wrong?
I mean the guy used a source claiming that Eurofighter has Thrust Vectoring…
His use of sources previously mean, as far as I’m concerned, he lacks credibility.
Wether he is wrong or not is another thing - when someone sends information you should address it.
Should I? I’m not obliged to believe someone who has used factually incorrect sources in the past.
I’m not obliged to spend copious amounts of my time and energy reading his tantrum throwing essays in which he says we’re all wrong and he’s right which, if we take past form, is going to have dubious sourcing at best.
It’d certainly be polite, nice of me, etc etc to do so. But if the moment I provide any form of contradiction he’s going to go for the “HES TROLLING DONT LISTEN TO HIM” approach why should I devote my time and energy taking him seriously?
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If you don’t want to believe him then there is no point for you to engage in a conversation with him. Might aswell not reply at all.
402 uses an inferior fan because they didn’t want to test the potential changes on the engine intakes:
You’re correct the 402 has a 10-20% increase in thrust over the envelope of the 400. 17,700 lbs of thrust is a ~ 110.6% improvement.
You cite a single line in that study saying the RM12 was aiming for “about 10-15% higher thrust”, which we know they achieved, 18,100 lbs is a 113.1% increase from the 400. But you ignore the line immediately afterwards saying the engine would also be tuned for lower right-hand corner envelope performance. We also know it has superior airflow at all airspeeds than the 400 and 402, due to the improved fans which the US didn’t opt for. So that implies it has an improved thrust curve at low and high speeds compared to the 400.
But somehow, you think that the slightly newer 402 has a far superior thrust curve to the RM12 because of some cherry picked some lines from a few papers? If anything the increased airflow of the RM12 would indicate that IT has the superior thrust curve, especially at subsonic speeds.
The copium will continue I’m sure. Until you definitively produce a source showing the 402 having a better thrust at various speeds than the RM12, then everything you’ve said is pure conjecture. Conjecture based on your knowledge and interpretation of sources, so we know we’re off to a winner.
This is completely fallacious. No document you have ever produced claims the RM12 was designed to have a 15% improvement in thrust at all speeds. It doesn’t specify any speed - the industry standard is to report static thrust, as that is generally the lowest…
175 < 190.
Diagram is also consistent with the RM12 having a higher pressure ratio than the 402, as advertised by GE on their website. Almost like they advertise their engines properly.
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Fair point.
Then again I’d make the point coming in with a condescending tone and then providing no credentials whilst… not listening to other people’s arguments is asking for a response of sorts.
Either way, he’s presumably getting what he wants, so I’m happy for him I guess.
Once again, you’re ignoring any argument I made about the static uninstalled thrust vs the installed dynamic thrust. Please take more time to understand what is being discussed.
Which is why instead of just saying things, I am providing sources and real arguments to the discussion. You’re just making jokes.
Sure, you could, or you know… you could provide a source that actually contradicts what I am showing you. I think that would be quite difficult, though… as the RM12 was designed for a 15% improvement (with potential 5% further growth down the road) whereas the F404-GE-402 was designed for a 20% improvement in the same area of the flight envelope from the get-go… and as we know thanks to the available data… it certainly met that 20% goal and exceeded it slightly.
That’s what I am wondering.
You could refute that source quite easily, I was probably wrong. This is a different discussion and unrelated… if you think I lack credibility that’s fine… please refute the sources I have posted or try to prove they aren’t credible if that is the case. You’ve done nothing to further your stance on the argument but ignore all of the good and valid data I’ve posted.
You’re pedaling the idea that static uninstalled thrust being higher for one engine means it has higher dynamic installed thrust as well…
It is shown that the RM12 was looking for a 15% improvement in thrust at the bottom right hand corner of the chart, the -402 looks for a 20% improvement in the same area. It goes on to say that the peak thrust is a limitation based on temperature limits… not airflow limits. It is stated that the RM12 fan would improve over the -402 only in the upper left hand corner of the flight envelope (high alt, slow speeds).
What I am showing you is the data for sea level, 0.8+ mach. This is where the biggest performance improvements for the engines are seen. No-where is it stated that the RM12 will achieve more than a 15% improvement in thrust in this area of the flight envelope, and we see that the -402 achieves +20%.
Correct, it has a 10% improvement at static uninstalled conditions. What we are discussing are the dynamic installed thrust conditions. At 1.2 mach, the -402 has nearly 21% improved thrust. The RM12 was designed for a peak improvement of around 15%.
No, that is what you are ignoring. The Engine is tuned for a 15% improvement in performance along the bottom right hand of the flight envelope (low and fast). The engine only achieves these higher combat ratings for limited periods of time, because the turbine inlet temps were not raised nearly as high as the -402 (+200 degrees for the -402 and only +165 degrees for the RM12, with a 190 degree increase being a temporary burst of power).
I think a temperature limited engine benefits from a lower pressure ratio when high speeds (especially at low altitudes) are involved. As someone else mentioned, the TF-30 will produce more thrust than the ‘improved motor’ that is installed on the F-14B because of similar conditions.
The only conjecture is that Gaijin “Thinks” (as stated in their response) that the RM12 should have higher performance than the -402. The data you keep trying to skew says otherwise.
GE stated the installed thrust not static thrust as an increase, so the company that produces both engines seems to vary wildly in this regard. The industry standard goes out the window.
That is literally what you did. Please counter the points I made in the discussion or don’t discuss at all. If what I was saying was so fictitious it would be easy to demonstrate how or why.
Yes, the RM12 has a higher flow fan. The airflow through the core of the engine is inferior to the -402 and there is higher friction due to the pressure ratios. The -402 design has lower friction due to pressure and higher temperature limits. It only makes sense that the -402 has a higher peak thrust rating than the RM12 while having a lower uninstalled static thrust value.
What exactly is the difference between the upper left and lower right of the flight envelope? I’m not familiar with the terminology, and I’ve seen it referenced plenty of times in the sources being posted.
Where have they ever said a 15% improvement at the bottom right corner of the envelope? You say yourself that the 402 was aiming for 20% improvement, and that they exceed it in some places, but it’s beyond the realms of possibility that the RM12 didn’t improve the thrust by more than 15% at different parts of the envelope?
You’re continuously lying and misrepresenting sources. Truly a MiG_23M moment.
They are discussing the flight envelope. The thrust changes with airspeed and altitude. The faster the aircraft goes, or higher it goes.
Going from left to right is increasing speed, and the higher up on the chart… the higher the altitude. Upper left is higher altitude, lower airspeed. Bottom right is lower altitude, higher airspeed.
If the -402 is temperature limited, has less friction from a lower pressure ratio and a higher temperature limit… then how is the RM12 producing more thrust at speeds where temperature is the limiting factor? It is stated the F-18 would not benefit from the RM12s fan except at high altitudes and low airspeeds. This is where it would only be flow limited, not temperature limited.
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Does anyone know what the sea level top speed of the F-18 should be?
According to the known data 1.2 mach is above the safe limit, but thrust values are shown. Based on the QNEP thesis the engine produces more thrust at 1.2 mach when at 5,000 feet than it would be able to at sea level which shows us the temperature limitation that is mentioned.
Got it so your argument is that the 402 produces more thrust at higher speeds low altitude, and the other side of the Argument is that across the entire flight envelope the RM12 produces more.
I think they are saying it can only produce more thrust than the -402 across the entire flight envelope, but I have already admitted that it produces better static uninstalled thrust. The curve of the -402 can be discussed at which point the values might cross over, but the truth is that the RM12 would have to be overperforming in-game since it produces drastically more thrust than the -402 at all airspeeds currently.
Firstly, your source says the 402 goes to +175, not +200 like you say. Temperature limit is not the only thing that impacts jet performance. Pressure ratio and airflow also matter, and we know the RM12 is superior in those categories.
The stuff about a lower pressure ratio is just pure copium. Just because you don’t understand the ins and outs of jet engine parameters doesn’t mean you can start making ridiculous generalisations.
The F-18 documentation that shows the final production engine has +200 are not permissible for sharing on the forums but can be found with google.
Regardless, the Gripens’ sustainable temperature limit is 165 degrees according to their documentation. It mentions a +75 degree improvement and a short duration +90 degrees above that. So, as we can see… they ended up with a improve +190 degrees from the +165 degree goal based on the newer documentations shared.
Similarly, the -402 had a 175 degree goal and ended up with +200 degrees. The difference is that the -402 doesn’t have to use a short burst increased power mode to get the higher limit.
You come in here to make fun of me as if I don’t know what I am talking about, but when I discuss something you don’t understand you are flippant about it and pretend I’m making stuff up. This is basic physics. Does a higher pressure ratio increase temperature more than a lower pressure ratio? YES.