Rushed for christmas, expect fixes (if any) after new years
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Hooray. Another New Year, another British aircraft under a rain of fixes.
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at least this one cant be 2 BRs too high like the hunters. you cant overtier a top tier
J-11A would be offended by this statement
There’s a reason the F-4 was so popular even into the 90’s and early 21st century
Not necessarily, you’re fully ignoring the engine cycle specifics
Don’t “british” my plane, call it european
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I mean “in British TT”. Gripen is not British either. Like Tornado, the year before, it’s not solid-british too.
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I could of course name three letters. But I don’t want to trigger Smin.
Would you mind elaborating
I would imagine one of the factors would be increased combustion temperatures and decreased losses due to extensive preventive measures against thermal deformation. I’m currently trying to find more documentation about HPC in it.
Still these weird “Mk.18” GBU-12s on the FGR.4 in the live server, and no EPW-II
https://community.gaijin.net/issues/p/warthunder/i/BeFvmev7bGtg
Sorry for weird notifications, the forum was giving me trouble but to answer;
For supersonic cruise the exhaust must flow faster than the free stream air coming into the inlet. If you want to go mach 1.5 in supercruise the exhaust velocity should be at least 1.5 mach. Air is usually slowed to ~0.45 mach before it enters the engine. To achieve high exhaust velocity in dry thrust you must not only accelerate the airflow from low subsonic to supersonic speeds, you must also overcome the bypass air equally slowed down to subsonic speeds as it mixes with the exhaust stream. A larger bypass will result in a larger amount of turbulence and friction that must be overcome to accelerate the exhaust stream to the desired speed.
For the F119 to cruise at supersonic speeds in excess of 1.7 mach without afterburner required a 0.3 bypass ratio and temp limits in excess of 1900K. The EJ200 having a larger bypass ratio would need to have considerably higher temps because higher pressures would be required to permit supersonic cruise conditions.
The British Defense Research Agency presented a document (page 51 of PDF) for the AGARD PEP Symposium on "Advanced Aero-Engine Concepts and Controls " held in Seattle, USA, from 25-29 September 1995 and published in CP-572.
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The point I wanted to get to with this document is the supercruise performance. This was not shown in the two requirements by the RAF but was discussed as an additional discriminator in the document, so that is what I am focusing on with this post. Feel free to read the LENGTHY description below;
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The first of the cycles shown seems to resemble the EJ200, with temp limits of 1850, 2000, and 2150 explored for SOT (stator outlet temperature), that being the turbine stator. The stator outlet leads into the turbine inlet if I am understanding this correctly and can be compared directly to the turbine inlet temperatures as a common unit of measure. Additional to the bypass ratio and SOT, they are also comparing the ‘T3’, or temp limits after compressor, as delivered to the hot section.
You can see then a engine with a bypass ratio of 0.15, 0.8, and two variable cycle designs ranging from 0.15 to 0.4 and 0.4 to 0.65. Beyond that, they are theorizing two 0.4 static bypass designs with component and cooling performance enhancements but only at the minimum temperature ratings.
Right away they make it clear that T3 (compressor outlet temps) becomes the limiting factor and NOT the stator outlet temps at approximately 1.8 mach. This also explains why the F119 is limited to around ~“1.7+” mach but it also has higher temperature limits than most other non-variable bypass designs and certainly higher than any peer for the decade it was made in.
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Again, for the fixed cycle engines it seems to indicate they are modeling the EJ200 or similar engine because it shares the design features such as convergent-divergent nozzle;
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Airframe considerations; 800 knots sea level top speed (mach 1.2), mach 2 altitude. Pitot style air intake (similar to Rafale, EFT, F-16, etc). Mounted underneath the nose.
Each engine is assumed 73.5 kg/s sea level static mass flow at a scale of 1.0 and it is scaled depending on airframe to meet the aforementioned requirements with the minimum required empty mass.
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The combat air patrol and intercept requirements seem to mirror the Typhoon’s requirements by the RAF.
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ON WITH IT THEN! About the supercruise mentioned before; Supercruise is an additional discriminator, notably it says the advanced engine designs (such as the variable bypass) have exceptional supercruise ability.
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More evidence it is indeed the EJ200 being discussed;
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Here it states the increase in operating temperature of the datum engine (EJ200?) to 2000K (1726C) will allow it to increase maximum supercruise from 1.13 to >1.4 mach. It is important to note that the airframe design used for the study is NOT a delta canard, and instead is a conventional tailed layout with inferior wave drag and supersonic performance will demand higher thrust, thus also higher temperatures.
The intercept mission aircraft was redesigned and resulted in better supercruise performance. In spite of still being a tailed design, the 1850K SOT permitted supercruise up to mach 1.36. It can be assumed that the Eurofighter thus would improve on the wave drag somewhat more than this. With a temperature limit of just 1800K in real life, the EJ200 would struggle to push the fighter up to 1.5 mach as claimed by the MOD. My working hypothesis is that this is not only inefficient, but requires the war power setting to accomplish. Even at 2000K the datum engine model can only push the intercept aircraft profile to ~1.46 mach.
The effect of bypass ratio as shown here; simply, the 0.4 bypass ratio engine requires considerably higher temperature limits for similar supercruise fall-out number to the 0.15 bypass ratio design. A bypass ratio of 0.8 is shown for comparison, maximum speed achieved was ~1.1 mach with an excessive temperature limit of 2150K.
@ShOt_MaCkEr regarding the rating schedule, document indicates that lower cycle temps at sea level will result in considerable loss in supercruise capability. The opposite should obviously be true if they increased it. We know the temperature limits of the EJ200 and the general characteristics match the datum engine in this document, though.
My point; the EJ200 with a bypass ratio of 0.4 and a turbine inlet temperature limit of ~1800K would require a much lower drag airframe and very likely a war time emergency power setting with increased temperature limit to achieve a supersonic cruise capability of 1.5 mach. Beyond this, that would be the maximum supercruise speed and not the efficient range. The efficient supercruise range would be to lower the throttle some, or the temperature limits and sit at a comfortable ~1.3 mach to extend the lifespan of the engine. Still, the wear and tear on the engine to be producing the maximum dry thrust would be more than subsonic cruise conditions but likely far more acceptable than supersonic cruise at maximum temp limit and output.
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Shouldn’t the Typhoon gr4 have additional flares pods like on the tornado gr4?
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You have said on here before
No. It has BOL permanently installed in the outer missile pylons instead
I am quoting the British Defense Research Agency, very very little of that post is my own opinion. Please read. I have not stated that I am an Abrams loader.
They didnt fix this yet
This is very much opinionated everything you say mostly is
I like you flag every time i speak to you
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