5Th generation: Is it a real or false term?

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Subject: 5Th generation: Is it a real or false term?
jessmo_24 4/1/2011 5:51:15 PM

*ttp://en.wikipedia.org/wiki/Fourth_generation_jet_fighter There is a debate raging on key publishing ATM discussing the true meaning of aircraft generations. some people are of the opinion that these generations dont even exist. Most people like me believe that these are the generations. 1st: Jet powered airframes, Guns, subsonic 2nd: Swept wings deltas alumminum alloys, semi-active missiles, radar. 3rd: Analog controls, better radars, better engines, blown flaps, canards,ECM and a host of other aerodynamic advances. 4th: Lifting bodies, BVR, doppler radar, relaxed stability vortex lift surfaces. 4.5: Advanced avionics, Post stall manuvering, high AOA. reduced RCS super cruising 5th: VLO, sensor fusion, super cruise, all in the same package. Please discuss and note my mistakes. Or is the entire generations concepts only somthing made up by silly Americans.

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MK epic fail shooter! 4/21/2011 11:20:43 AM

The differance between the two engines have nothing to do with their date of introduction, or much more important the date of inception wich makes the F-100-229 the newest engine by far, but because of the design choices made at that inception. The Bypass ratio means that under cruise conditions the engine with the highest ratio is the most efficiant. The F-100-229 is about 20% better than the older M-88. Because the RB-199 predates the F-100-229 by a bunch, does not mean that it has nor been up graded since then. When the French chose a BPR of 0.3, they knew it would not get as good SFC as the engine whith a higher BPR of 0.36! Thats a fact! There is also absolutely NOTHING they can do to over come that difference! NOTHING!!!

1.) The RB199 is completely unrelated to the M88, the fact that you believe that these two engines are somehow linked to each other speaks volumes about your weak knowledge here!

2.) ONLY the F-15E is powered by the F100-PW-229, ALL F-15A-D were/are powered by the F100-PW-100/200/220/220E! That's a fact, maybe you consult more reliable sources the next time! The fact that you don't even know such basics about the very aircraft you intend to make a case for once again demonstrates a clear lack of factual knowledge!

3.) As a thumb rule: Higher BPR means more fuel efficiency, yes! But that's not the sole factor and the difference is insignificant in comparison to turbofan engines powering airliners, those have a BPR up to 2! Military turbofans have different requirements, they must be powerful and efficient at supersonic speeds as well and that's why they all have a BPR far below 1. Again as a thumb rule lower BPR = greater thrust efficiency at supersonic speeds. That's why the supercruising F119 engine has a BPR of just 0.2. And for the record the F135 has a BPR of 0.57 and just a SFC of 0.8 lb/lb/h according data I have seen...And there are certainly many more examples which contradicts your assertions!

4.) It's interesting that you left out the EJ200 of the Eurofighter which has a BPR of 0.4. You probably figured that during your google search and left it out for obvious reasons. According your own logic the EJ200 must be more efficient than the F100 for that simple fact and this would contradict your claim that the F100 is more efficient than both the M88 and EJ200.

5.) TWR of an engine is a good indicator of thrust efficiency! The F100 is inferior here to both the M88 and the EJ200. Interestingly you didn't lost a single word about this. What is a higher pressure ratio worth if thrust efficiency is still inferior? And what a surprise that an engine with 1.5 times more compressor stages achieves a better pressure ratio.

As to accelleration time, let us state that it is much less for the F-15 to go from M-0.8 to M-2.5 than it is for either of the ECDs to go from M-0.8 to M-2.0! About 80% as long! More important is the time from M-0.8 to M-1.2 which is about 64% of the time required for either of the ECDs.

Sure and this is based on what data? You throw around with percentage numbers, but those percentage numbers require hard numbers in the first place! Where are they!? Once again crappy assertions, no facts and just made up stuff!

1. The F-15 has, because of it's design configuration, less drag at cruise speeds, than either ECD. ( More Aspect Ratio, Variable Inlets, extreamly good design!) The choices that they made for BOTH of the ECDs was the canard delta with less AR and higher induced drag at cruise speeds and low AoAs.

Once again an over simplified single point analyse. The variable inlets have no positive impact on the drag of the aircraft and that fact that they are variable is owed to the fact that the engines wouldn't be adequately supplied without them at high AoAs and the high speed requirements. The ECDs have there intakes located in a position where the airflow of the fuselage is promoted into the intakes reducing the need for variable inlets. One of the greatest issues with your comparisons is that you want to apply thumb rules on everything, but that only works if everything else is the same. Unfortu

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45-Shooter 4/22/2011 1:31:59 AM

Talk to him about engine core temps, the type of thrust nozzle that comes off the combustion pot, the fan spool melt temps, and the type of air flow ramps in the intake tunnels, MK. Lets talk about all of these things, but much more importantly, lets also talk about Pressure and Bypass Ratios!!! These two design parameters are more influential than almost all other things, but possibly Turbine Inlet Temp! Note that TIT can not make up for choices made in the BPR and PR, it can only make those choices more or less efficient. TIT is a mixed blessing. More and the engine is more efficient, but more maintenance intensive with shorter TBOs and Closer Inspections. You pays yo money and takes yo choice!

Also ask him about 'wetted' area when it relates to aircraft. It's not as important as the wetted area of submarines! Lets talk about wetted area! Lets also talk about Remolds Numbers! In what way do the three aircraft relate between "Wetted Area" and installed thrust? What are their T/D ratios? How can you determine the relative ratios of the three planes? What about fineness ratio? How does that relate to the T/D? How does T/D change with speed? All good questions, that I bet none of you can answer!

I don't want to waste time with Shooter, but it isn't that simple when you discuss engines their thrust, the plane airframe and its drag, etc. You are absolutely right! It's not nearly that simple, but making comparisons is! Does any one here know how to do that?

Shrug. The plane is a flying compromised bridge load that constantly changesphuasical mass and balance point from takeoff to landing. Just how fast you go changes the whole way the plane handles, generally with a tail-pusher (modern jet) becoming harder to keep point the faster you go into transonic and the higher you climb into thin air. You are absolutely right!

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heraldabc 4/22/2011 1:36:52 AM

What did you miss about:

Herald

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heraldabc 4/22/2011 1:43:43 AM

What has a submarine to do with air when it unsticks from an aircraft skin? Hint:

lift induced drag.

'Wetted' does not mean what you think it does.

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45-Shooter 4/22/2011 2:34:08 AM

1.) The RB199 is completely unrelated to the M88, the fact that you believe that these two engines are somehow linked to each other speaks volumes about your weak knowledge here! I never said it was! The RB-199 was the original starting point by way of XG-40 for the EJ-200! We were talking abour all three planes and engines were we not?

3.) As a thumb rule: Higher BPR means more fuel efficiency, yes! But that's not the sole factor and the difference is insignificant in comparison to turbofan engines powering airliners, those have a BPR up to 2! But it is significant between to similar fighter plane engine when one has a 20% advantage! Military turbofans have different requirements, they must be powerful and efficient at supersonic speeds as well and that's why they all have a BPR far below 1. Absolutely true! Again as a thumb rule lower BPR = greater thrust efficiency at supersonic speeds. Absolutely true! That's why the supercruising F119 engine has a BPR of just 0.2. And for the record the F135 has a BPR of 0.57 and just a SFC of 0.8 lb/lb/h according data I have seen...And there are certainly many more examples which contradicts your assertions! Yes it does, but you very answers rase many questions! Such as, if the F-15C has a higher BPR, then it should make the plane slower at Super Sonic Speed, but it does nor, why is that?

4.) It's interesting that you left out the EJ200 of the Eurofighter which has a BPR of 0.4. Not intentionally! You probably figured that during your google search and left it out for obvious reasons. According your own logic the EJ200 must be more efficient than the F100 for that simple fact and this would contradict your claim that the F100 is more efficient than both the M88 and EJ200. On the surface this would be true, but you forgot the other half of the equation, the Pressure Ratio! What is the PR of the EJ-200? It is one more reason why the Typhoon is a better plane than the Rafale, but not as good as the F-15!

5.) TWR of an engine is a good indicator of thrust efficiency! Absolutely true! The F100 is inferior here to both the M88 and the EJ200. Absolutely true! Interestingly you didn't lost a single word about this. Absolutely true, but not relevant! There are many other design parameters that effect this including installation and longevity requirements!What is a higher pressure ratio worth if thrust efficiency is still inferior? And what a surprise that an engine with 1.5 times more compressor stages achieves a better pressure rat

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MK 4/22/2011 9:00:34 AM

I never said it was! The RB-199 was the original starting point by way of XG-40 for the EJ-200! We were talking abour all three planes and engines were we not?

You throw the RB199 in between your claims about the M88. And for the matter the XG-40 was a technology demonstration programme to develop and test NEW core engine technologies only. It formed the base for the EJ200 but it is unrelated to the RB199 as well. The EJ200 has nothing to do with the RB199, there was just a similar requirement wrt the physical dimensions and that's it.

Look up F-15C!

No need to, I have done so over the last 2 decades and I know for a fact that the -229 is not used by any other variant than the F-15E.

But it is significant between to similar fighter plane engine when one has a 20% advantage!

The EJ200 has a 10% "advantage" over the F100... Advantage is relative here.

Yes it does, but you very answers rase many questions! Such as, if the F-15C has a higher BPR, then it should make the plane slower at Super Sonic Speed, but it does nor, why is that?

You at least barely grasp the point that a single factor does not determine everything, it contributes its part and that's it.

On the surface this would be true, but you forgot the other half of the equation, the Pressure Ratio! What is the PR of the EJ-200? It is one more reason why the Typhoon is a better plane than the Rafale, but not as good as the F-15!

The BPR of the EJ200 is 26:1 achieved with 8(!) compressor stages vs 13 in the F100! TWR of the EJ200 is >9:1 vs <8:1 for the F100.

Absolutely true, but not relevant! There are many other design parameters that effect this including installation and longevity requirements!

Suddenly hinting at other factors huh? Of course there is more about an engine other than a single factor be it BPR, TWR, PR etc. A higher TWR indicates a more efficient design however and usually reflects a more advanced engine. The F100-229 was introduced in 1991, the production M88-2 was cleared in 1996, the production EJ200 in 1997.

Absolutely true! BUT, it does not change that fact! The one engine IS more efficiant in some ways, that I have noted, and it would seem to more Nations that have bought the F-15 in compitition with the Typhoon at least partially because of it.

LMAO, sure international customers selected the F-15 over the Typhoon on engine grounds. There were other much simpler factors. It is called maturity!

Absolutely true! But nothing is ever the same is it? There are only different choices and the results that come with them! Which is my entire point!

Correct.

Absolutely true! That is why the ECDs have less drag at high angles of attack! Which I have pointed out time and time again. So the designers traded low drag at cruise for low drag at high loadings.

Did you actually read what I gave written? In ALL stages of flight from CRUISE to manoeuvre. It's not for manoeuvring only!

+Pilot, Eight missiles and the CL Tank = 21,104 @ 355.95 kg/sqm

I easily get over 22t if we talk about such a configuration. Even if we assume simplified 4 x AIM-9 (87 kg each), 4 x AIM-120 (150 kg each), 1 CT (2270 l) and a pilot (100 kg equipped). Add gun ammo, decoys and pylons for the wings and centre line and you get over 22 t.

Wiki is wrong. Dasault states " 10 Tonne Class" on their web page, other sources state 10.45 and 10.87T But who cares!

10 t class isn't wrong as there are 3 different variants of the Rafale. The 9500 kg figure applies for the single seat land based variant Rafale C.

Sources:

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45-Shooter 5/9/2011 11:26:14 PM

An important factiod to remember is that the EF 2000/Typhoon requires at least one, if not two Drop Tanks to fly the same unrefueled mission.

As does the F-15. The Eagle's range on internal fuel is modest. Right will either ECDs fly 1,085 NMi. WO DTs?

Long range and endurance is achieved with large external drop tanks only. Not true! Depending on mission requirements, it is about 600 miles WO Drop tanks or FAST Packs. On internal fuel the aircraft does fly any farther than a Typhoon or Rafale. You are delusional! F-16A's already offered better range on internal fuel than the F-15A which isn't surprising as the F-16A had 60% the fuel capacity at 50% of the weight and engine thrust.You are delusional! This changed somewhat with the F-15C which holds 900 kg more fuel than the A, but which is also somewhat heavier.

Such details aren't available in the public. I doubt you could tell me those for the F-15 with DTs either. Clean range with eight missiles, 940 rounds of 20 MM and a 90 kilo pilot is 1,087 NMi.

Must fly from Italy, Sisley, Crete or Alexandria to a MAR point somewhere over the Mediterranean Sea, which is beyond the range of SA-5 located in Libya, then on to Libya, perform CAP with six BVR and two WVR missiles for 1.5 hours on station, perform interdiction of Kaddafi's Forces, then return to base, or MAR, then on to Alexandria!
That alone contradicts. Engaging forces on the ground with AMRAAMs and Sidewinder? You forgot about the no fly zone as that is the only config where the ECDs have a whiff of F-15 jet fumes!

Not everything, just what is MOST IMPORTANT during ACM!

Thrust alone won't compensate for inferior aerodynamics... If thrust would be everything one has to wonder why aerodynamics were further developed and changed with each generation. Why do you think that the F-15's aerodynamics are not supirior to any Canard Delta? It all depends on which criterion you want to measure. In the parts of the envelope where the ECDs are better, they can be easily compensated by more T/W! In those parts of the envelope where the F-15/16/18 is supirior, no amount of T/W can help!

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45-Shooter 5/9/2011 11:54:26 PM

In which way are the much newer and more advanced engines on the ECDs less efficient?
Because of the choices they made at the design stage! They chose more thrust at high speed and less at cruiseing speeds.

Once again an empty phrase... What's the range of the F-15 with internal fuel and that of the others? What's the combat radius in similar mission profiles...? I doubt you'll be able to come up with anything credible, physics are against you as are the numbers available.
Hardly. Depending on the mission profile, the F-15A/C can go well over 1,000 NMi WO any extra tankage! None of the makers web sites list a bare range even close to that! NONE!

Stewart first post; They don't have to be to know that the planes do not turn as well with tanks as WO! None of the ECs can maneuver with the F-15 with the CL 600 Gallon Tank! Regardless of their total fuel state! The F-15C can go M-2.5 with eight missiles and the CL Tank! None of the ECs come close! Note that speed per pound of T/D is a valid way to compare to vastly different planes as to their T/D and T/D! In reality, we should be comparing the F-16 Block -60 to the ECs.

Your reply; Who do you want to fool dude? The F-15 won't go much beyond M 2 with the load you described and the max. is not more than M 2.3 except you want to fuck up airframe and engines within a single flight.
Again you are delusional! The F-15's top speed is limited by the FCS to M-2.5 to prevent the things you note! It hase much more thrust than required to go 2.5 with the CL Tank, eight missiles and 940 rounds of 20 MM.

The greater speed is owed to the inlet configuration in the first place and is entirely irrelevant in combat anyway as you will neither reach it in any operational configuration, nor will you reach it in any reasonable time frame and with enough fuel left.

These are the silliest things said in a long time. What makes you think that it would take the F-15C as long to reach M-2.5 as the Rafale takes to reach M-1.8

By what measure do you think the F-15/16/18/22/35 have inferior aerodynamics? That is he silliest thing I've heard in months! Is it their Aspect Ratio, no wait, they ALL have better ARs than any of the Euro-Canards? Induced drag, but no wait, the planes with higher ARs have less drag per pound in low load conditions! Lets see, during that 1% of 1% of flight time in which they are under high load maneuvers, they have lower T/D, but wait, it's not high enough to overcome the advantage of higher T/W! Oh my, what do we do?

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45-Shooter 5/10/2011 1:09:38 AM

1.) The RB199 is completely unrelated to the M88, the fact that you believe that these two engines are somehow linked to each other speaks volumes about your weak knowledge here!

I never said it was! I said it was related to the EFT-2000's engines.

3.) As a thumb rule: Higher BPR means more fuel efficiency, yes! Military turbofans have different requirements, they must be powerful and efficient at supersonic speeds as well and that's why they all have a BPR far below 1. Again as a thumb rule lower BPR = greater thrust efficiency at supersonic speeds. That's why the supercruising F119 engine has a BPR of just 0.2. And for the record the F135 has a BPR of 0.57 and just a SFC of 0.8 lb/lb/h according data I have seen...And there are certainly many more examples which contradicts your assertions!
But you make all of my points. BPR IS important! So are the choices made as to the shape of the thrust profile. Finnally, you have mixed the numbers from the two different types of F-135 engines and the T/W of the F-135 is what?

I did not post the figures for the EJ200 because I did not think them realivant and you are right about the EJ200's BPR! But it has a PR of only 26-1 compaired to the F-100's 32-1. Both numbers are important and when combined, relate to the f

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MK 5/10/2011 8:06:04 AM

Stop wasting my time and get your facts straight kid. Here are some REAL data on the F-15C and not your lame self invented crap numbers:

h*tp://www.alternatewars.com/SAC/F-15C_Eagle_SAC_-_February_1992.pdf

Good bye

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