Aircraft Vs Thread 5

[F-ZeroOne]

No Typhoon crashes that I know off but one suffered a front landing gear failure I think.

[edwin3060]

The F-22 is already a perfected design. We need a high performance fighter to take on the MIGs and flankers of the third world.

I believe their has only been one crash of a F-22, and that was during the early testing period in the early ninety's.

I don't know how many Typhoon and Griffins have crashed.

The only all American alternative is some kind of super eagle retread.

Does any one know how much heaver the strike eagle is to regular eagle?

I wouldn't say that it is 'perfected', given that half the fleet of F-22s are outdated and need billions to be brought up to speed. Reports have also come in that normal maintenance on them is taking more time and money than expected. Not to mention that the Raptor still doesn't have a HMD.

Edited March 8, 2009 by edwin3060

[Noyhauser]

Yes it is-- I believe I said an F-15 in the size and weight of an F-16 --- it is also much much harder to replace a composite panel than a metal panel since composite panels are glued together and not riveted-- much more 'single-piece' construction is also used which saves weight but makes maintenance hell. Note: The reason why they cut short the life of the F-15 was that they detected the increased metal fatigue-- you have no such thing with composites-- the only indication that the composites are not performing as they are designed to are when your expensive 100 million dollar plane falls out of the sky for no reason. And, like I stated, composites have many other modes of failure that metals do not have, so you are basically trading one for another.

You are wrong about the Tornado replacement-- The Eurofighter was initially marketed to replace all Tornado variants, as well as the F-104G interceptors in German and Italian service-- If you look at the early marketing materials you will notice that some of them prominently feature missiles such as the Storm Shadow, LGBs and such. Eventual politicking pushed back the air-to-ground capabilities, which is why it doesn't have them now. In this way, the Eurofighter is more like multirole fighters such as the F-16 and F-18, rather than a pure air-superiority fighter like the F-15 (which is not to say that it is deficient at A2A).

First off, what proof besides your own views on composites do you have that the Eurofighter will have greatly increased life-cycle costs due to composites like you claim? You haven't brought any beyond your conjecture about the subject. Its been used with growing frequency over the past thirty years and failures of the type you describe (de-lamination, brittleness ect.) are rare from what I've seen. Moreover the technology has been constantly improving; look at the tests they did on the 787 wing where they bent it at a ridiculous angle, which were linked earlier in this thread.

While Carbon fiber is used extensively on the Eurofighter, approximately 40% of weight, in key damaged prone areas (leading wing edge and flaperons) titanium is used. Yet other aircraft, like the F-18E and F-22 also has significant application of carbon fiber in the same places as well, to a lesser extent. The F/A-18's wings (except at the root wingbox) are made completely of carbon epoxy, even the leading edge. So the Eurofighter is by NO means unique in its use of non-metallics and other airframes would face the same vulnerabilities, if such a vulnerability exists at all.

Second, F-15Cs WERE falling out of the sky just in precisely the manner you described. It took the crash of a F-15C in Missouri in November 2007 for the Air Force to discover that the longerons were deteriorating and leading to catastrophic failures. Same thing happened in 2002 when a vertical stabilizer flew off a F-15 over the Gulf of Mexico, leading to the replacement of all A-C model's stabilizers in the fleet. So no it wasn't your precious NDT that helped figure out the problem, but catastrophic failures. They couldn't anyway; think about ALL the aircraft in the US inventory and all the parts that required to be tested. Its ridiculous to think they could test for every possible contingency. Oh and there are a growing number of testing methods available for composites which can test for fatigue and damage.

Finally, again its not "politiking" that is holding up the Tranche 3, at least not in the way you're suggesting. Defence budgets in Europe have seen moderate increases in the past decade, particularly after the signing of the European Capabilities Action Plan. Between 1999 and 2001 the main concern was based on prosecuting another Kosovo type operation; In the parlance of the Petersberg goals (which set out the types of operation that the EU would be involved in). Had the security environment remained the same, its almost certain that Tranche 3 would have been produced.

However since 9/11 the threat assessment completely changed, with the focus shifting to counter insurgency or stability operations in places like Afghanistan, Iraq, Sudan/Chad, and Lebanon. In reality Defence spending hasn't gone down in European countries since 9/11, its remained roughly constant. However funding has been transferred, either to operations or to capital projects relevant to current operations. These decisions aren't really political; they are administrative in nature, made by senior defence officials allocating budgets based on the outlays made by finance departments and politicians. Why would the UK or Netherlands need a Tranche 3, when the main need is stability operations not A2G, the present capabilities are sufficient, and a replacement is on the horizon with the F-35. Thats the nature of Defence administration, adjudicating between the requests of the various service requests, the threat environment and the broad political aims.

So, any other untruths you'd like to trot out as facts?

Edited March 8, 2009 by Noyhauser

[edwin3060]

First off, what proof besides your own views on composites do you have that the Eurofighter will have greatly increased life-cycle costs due to composites like you claim? You haven't brought any beyond your conjecture about the subject. Its been used with growing frequency over the past thirty years and failures of the type you describe (de-lamination, brittleness ect.) are rare from what I've seen. Moreover the technology has been constantly improving; look at the tests they did on the 787 wing where they bent it at a ridiculous angle, which were linked earlier in this thread.

While Carbon fiber is used extensively on the Eurofighter, approximately 40% of weight, in key damaged prone areas (leading wing edge and flaperons) titanium is used. Yet other aircraft, like the F-18E and F-22 also has significant application of carbon fiber in the same places as well, to a lesser extent. The F/A-18's wings (except at the root wingbox) are made completely of carbon epoxy, even the leading edge. So the Eurofighter is by NO means unique in its use of non-metallics and other airframes would face the same vulnerabilities, if such a vulnerability exists at all.

Second, F-15Cs WERE falling out of the sky just in precisely the manner you described. It took the crash of a F-15C in Missouri in November 2007 for the Air Force to discover that the longerons were deteriorating and leading to catastrophic failures. Same thing happened in 2002 when a vertical stabilizer flew off a F-15 over the Gulf of Mexico, leading to the replacement of all A-C model's stabilizers in the fleet. So no it wasn't your precious NDT that helped figure out the problem, but catastrophic failures. They couldn't anyway; think about ALL the aircraft in the US inventory and all the parts that required to be tested. Its ridiculous to think they could test for every possible contingency. Oh and there are a growing number of testing methods available for composites which can test for fatigue and damage.

Finally, again its not "politiking" that is holding up the Tranche 3, at least not in the way you're suggesting. Defence budgets in Europe have seen moderate increases in the past decade, particularly after the signing of the European Capabilities Action Plan. Between 1999 and 2001 the main concern was based on prosecuting another Kosovo type operation; In the parlance of the Petersberg goals (which set out the types of operation that the EU would be involved in). Had the security environment remained the same, its almost certain that Tranche 3 would have been produced.

However since 9/11 the threat assessment completely changed, with the focus shifting to counter insurgency or stability operations in places like Afghanistan, Iraq, Sudan/Chad, and Lebanon. In reality Defence spending hasn't gone down in European countries since 9/11, its remained roughly constant. However funding has been transferred, either to operations or to capital projects relevant to current operations. These decisions aren't really political; they are administrative in nature, made by senior defence officials allocating budgets based on the outlays made by finance departments and politicians. Why would the UK or Netherlands need a Tranche 3, when the main need is stability operations not A2G, the present capabilities are sufficient, and a replacement is on the horizon with the F-35. Thats the nature of Defence administration, adjudicating between the requests of the various service requests, the threat environment and the broad political aims.

So, any other untruths you'd like to trot out as facts?

Uhh... maybe about 3 years (and ongoing) education in Materials Science and engineering? I'm not here to state that Composites are the devil's material, so get that sand out of your vagina I'm just here to say that Composites are just as fallible as any other material, with new, relatively less known methods of failure that are harder to predict. If F-15s can fall out of the sky even with all that we know about the metallurgy of steel and titanium, just think what could happen with composites. Unfortunately I'm gonna have to take a rain check on this argument until about 2025 at least .

Also, even if there are marginal increases in defence budgets, clearly they aren't enough to ensure that the Eurofighter gets onto the production line with the capabilities it was DESIGNED for. By your reasoning, there should be even more of an impetus for an air to ground capability for the Typhoon, yet this wasn't materialized. And if you think there is no role for air to ground support fire in counter-insurgency or stability operations, you've been missing out on a lot of whats going on in Iraq Either way, I don't care-- I was just responding to those who asserted that the Typhoon lost the fighter competitions in Korea and Singapore even though it was a superior platform--- because it is not in several ways.

[David Hingtgen]

IIRC the F-15 failures were due to being manufactured incorrectly, with undersize stringers. Every one that was built correctly is fine. It had nothing to do with "not fully understanding the nature of the materials used".

[edwin3060]

IIRC the F-15 failures were due to being manufactured incorrectly, with undersize stringers. Every one that was built correctly is fine. It had nothing to do with "not fully understanding the nature of the materials used".

Were they undersize even according to the original specifications, or are they called 'undersized' now that the crash investigations are over? Because if they were manufactured to the wrong specs, I would agree with you, otherwise, it could be simply an overestimation of the strength of the part, which would be a materials problem.

[hobbes221]

Hey just found this!

http://www.360cities.net/image/luftfahrtmuseum-07

[David Hingtgen]

OMG! OMG OMG OMG OMG. V-tailed stealth F-15 with internal AMRAAM bays mounted in the CFTs to match the F-35's radar signature. It's real.

http://www.flightglobal.com/blogs/the-dewl...tealthy-f-.html

And the missiles swing out on rails: http://link.brightcove.com/services/link/b...ctid16748936001

[miles316]

OMG! OMG OMG OMG OMG. V-tailed stealth F-15 with internal AMRAAM bays mounted in the CFTs to match the F-35's radar signature. It's real.

http://www.flightglobal.com/blogs/the-dewl...tealthy-f-.html

And the missiles swing out on rails: http://link.brightcove.com/services/link/b...ctid16748936001

Is that a full scale aircraft, or a model?

It does not have a S-shaped intake, of all the stuff I have read on stealth technology the compressors of a turbo fan engine is the most reflective part of a airplane.

Edited March 17, 2009 by miles316

[Shin Densetsu Kai 7.0]

Wow....wasn't expecting another Eagle variant but that's rather neat!

[Vifam7]

OMG! OMG OMG OMG OMG. V-tailed stealth F-15 with internal AMRAAM bays mounted in the CFTs to match the F-35's radar signature. It's real.

http://www.flightglobal.com/blogs/the-dewl...tealthy-f-.html

And the missiles swing out on rails: http://link.brightcove.com/services/link/b...ctid16748936001

Other than the swingout rails and V-tail, I don't see how much stealthier this F-15 can be over the current Eagles. Perhaps a slight improvement for sure. But they must be exaggerating about equating the F-35's radar signature (even if it's just the frontal aspect).

And wouldn't all this stealthiness be compromised just as soon as they hang something on the wings?

Edited March 17, 2009 by Vifam7

[F-ZeroOne]

Okay, which Boeing staff member is a Patlabor fan then?

The F-35 will have the same problem with hanging things on the wings. I could see an upgraded F-15 being an attractive option for those international customers in the market for fighter upgrades; I suspect this thing isn't just aimed at potential F-35 customers but Rafale/Typhoon/Gripen customers as well.

Still, neat as it is (why the V-tail, though? Stealth?), doesn't mean it'll get taken up - remember the F-20 and F-18L...?

[miles316]

Okay, which Boeing staff member is a Patlabor fan then?

The F-35 will have the same problem with hanging things on the wings. I could see an upgraded F-15 being an attractive option for those international customers in the market for fighter upgrades; I suspect this thing isn't just aimed at potential F-35 customers but Rafale/Typhoon/Gripen customers as well.

Still, neat as it is (why the V-tail, though? Stealth?), doesn't mean it'll get taken up - remember the F-20 and F-18L...?

Can they incorporate the avionics from the F-22 Raptor (RADAR, FlyByWire, and ECM), and supper cruse.

[F-ZeroOne]

Going by a couple of related articles, it would be fitted with an AESA radar and a digital flight control system, though I doubt it would have the "all-round" sensor capability of the F-22. Supercruise...? Mmm... guess it would depend on the engines, but I'm no expert...

[Bri]

IIRC the Eagle has a massive frontal radar crossection due to its intakes, which were optimised for high speeds to intercept the MiG 31Foxbats. This version should remedy that I guess.

"Convenient" for Boeing to have a upgraded F15 ready now Lockheeds F22 production is in doubt.

[David Hingtgen]

The Super Hornet has big square intakes too you know, and it's only just below the Typhoon etc for stealthiness---it has baffles in the intakes, and another article I just found said the production Silent Eagle with have them, as well as "coatings". (also, an F-15's intakes are not as straight as they look---you cannot see the compressors THAT easily---the F-14 is much worse--an F-15's engines are mounted much closer to each other than the intakes are---there is a decent S-curve in there, more so than the F-18 has)

Supercruise----technically, yes most likely, but not usefully. An F-15 normally cruises at .9, doing 1.01 or something is kinda pointless. (lots of modern jets can BARELY supercruise when clean----the YF-23/22 can do 1.4+, that's their real point--it's not merely supercruising, it's going well beyond Mach 1 that's the real speed benefit)

Finally--it is a "Silent Strike Eagle"--they can fit the 1,000lb JDAM and SDB inside, including mixing them with AMRAAM or Sidewinder in the bays at the same time.

As for who's getting them---smart money's on Japan. They want the F-22, this is the next best thing. (F-35 simply is not that good in air combat from everything I've read---they won't even say it can match an early F-16) Japan wants the F-22 for pure air-to-air, the F-35 would be a very expensive inferior substitute--they don't want a cheap, multi-role plane like most nations---they want a truly kick-ass air superiority plane---there's not many options for that nowadays.

[miles316]

Going by a couple of related articles, it would be fitted with an AESA radar and a digital flight control system, though I doubt it would have the "all-round" sensor capability of the F-22. Supercruise...? Mmm... guess it would depend on the engines, but I'm no expert...

Super cruse like what the Griffin has is a result of the aerodynamics of the aircraft not the engines. Popular Mechanics had a article a few years ago; Boeing had planed to develop a 777 size airliner. The Aircraft would have high subsonic cruse capability which was made possible by using computational fluid-dynamics modeling which allows the engineers to maximize air flow for maximum performance. In the article Boeing had tried it out on a F-15 and it broke the sound barrier with out using it's afterburner.

Edited March 17, 2009 by miles316

[Vifam7]

As for who's getting them---smart money's on Japan. They want the F-22, this is the next best thing. (F-35 simply is not that good in air combat from everything I've read---they won't even say it can match an early F-16) Japan wants the F-22 for pure air-to-air, the F-35 would be a very expensive inferior substitute--they don't want a cheap, multi-role plane like most nations---they want a truly kick-ass air superiority plane---there's not many options for that nowadays.

I agree that this aircraft would be an very attractive option for the JASDF. Perhaps Boeing's answer to the Typhoon?

I wonder if Australia is regretting buying the Super Hornet. ^^;

Not that the Super Hornet is bad aircraft. Just that they too wanted the F-22 and this aircraft would seem to offer a bit more than the SHornet.

Edited March 17, 2009 by Vifam7

[David Hingtgen]

For the RAAF many will be converted to EA-18Gs anyways, so they could just get these instead of F-35s or something---or buy just a few to supplement them. And the new Eagle is still over a year away from flying, much less in-service. (it'll still beat the F-35 though)

While the RAAF Shornets are literally being built as we speak. And unlike Japan, Australia really does want more of a strike/interdiction plane, the Super Hornet's very good at that.

[anime52k8]

Okay, which Boeing staff member is a Patlabor fan then?

-snip-

Still, neat as it is (why the V-tail, though? Stealth?), doesn't mean it'll get taken up - remember the F-20 and F-18L...?

the V-tail is for stealth, out/in canted tails produce less of a radar return, I forget why.

anyways, the Eagle plus is still way better looking...

[David Hingtgen]

I do wonder about the effect on V-tails for yaw stability---the F-15 originally had shorter fins with ventral fins---the ventrals were eliminated, so the verticals had to be extended. A primary goal of all planes is weight, so they always have the "minimum" structure needed for stability and control. Possibly the CFTs actually enhance yaw stability? Or if it never carries external weapons, it doesn't need as much yaw "protection" and a clean-config F-15 can get by with less effective v.stab area?

Or perhaps production v-tails will be larger to cope. (if they go with all-new fins, they could really change things, make them trapezoidal etc---the ones seen today are specifically mentioned as basically being mock-up stabs)

[miles316]

the V-tail is for stealth, out/in canted tails produce less of a radar return, I forget why.

anyways, the Eagle plus is still way better looking...

Stealth is half RAM half geometry no stealth aircraft hase right angles. The 90 degree angles of the vertical tail give off a large amount of RADAR reflections, and by giving it a slight cant you reduce the RADAR return.

[Bri]

As for who's getting them---smart money's on Japan. They want the F-22, this is the next best thing. (F-35 simply is not that good in air combat from everything I've read---they won't even say it can match an early F-16) Japan wants the F-22 for pure air-to-air, the F-35 would be a very expensive inferior substitute--they don't want a cheap, multi-role plane like most nations---they want a truly kick-ass air superiority plane---there's not many options for that nowadays.

The Japanese airforce wants the F-22, doubt they will accept the second/third best option easily. Their government would lose polical leverage in the negotiations if they'd even consider voicing support for an F15 upgrade.

[David Hingtgen]

Lot more info in the powerpoint:

http://www.slideshare.net/TheDEWLine/silen...type=powerpoint

[Vifam7]

What would the pundits say about this F-15SE being able to carry only 4 AMRAAMs if it wants to maintain it's stealth characteristics? Granted it's the same criticism leveled at the F-35.

[F-ZeroOne]

Super cruse like what the Griffin has is a result of the aerodynamics of the aircraft not the engines. Popular Mechanics had a article a few years ago; Boeing had planed to develop a 777 size airliner. The Aircraft would have high subsonic cruse capability which was made possible by using computational fluid-dynamics modeling which allows the engineers to maximize air flow for maximum performance. In the article Boeing had tried it out on a F-15 and it broke the sound barrier with out using it's afterburner.

Sorry, Griffin? Do you mean Gripen? (I presume its the Swedish word for the same thing, though... ) I also assume you're referring to Boeings "Sonic Cruiser", which IIRC was killed off by fuel costs and airline disinterest (the spoilsports, I want to fly faster! ).

Also, I've just remembered where I've seen a fighter firing a missile from a FAST pack before - seems Boeing also has some Macross Plus fans on the payroll too...

Edited March 18, 2009 by F-ZeroOne

[edwin3060]

It would basically be an F-22 sized F-35 with slightly better kinematic performance trading off against poorer all-round RCS, and the lack of a DASS.

However, I think some mention has been made that the CFTs could be retrofitted onto older airframes, and Boeing is looking into a retrofit/upgrade kit that is compatible with older F-15s as well, so it could be a very viable mid-life upgrade for the F-15! Boeing mentioned that the V tails generate some extra lift as well. The F-15SE would be expected to operate with and without external stores, so there must be some way to compensate for the loss of yaw stability-- perhaps the V tails are larger, but incorporate composites to make them lighter?

One problem with the inlet is that it is variable geometry, whereas the F-22, F-35 and F-18 have fixed geometry inlets which can be optimized for stealth-- a truly stealthy inlet would have to be fixed, which would probably play hell with the engine performance of the F-15. Seeing as to how Boeing has said that the top speed of the Silent Eagle would not be affected, it may well be the case that the inlet can be 'fixed' in one position when stealth is required, and allowed to vary it's geometry when speed/cruise performance is required instead.

Boeing also said that only the frontal RCS would be equivalent to the F-35-- which means it will do jack squat against a properly laid out ground based air-defence grid (since the side and bottom RCS would still be large), but could be useful against enemy fighters when moving into the merge.

Also, Supercruise is due to both aerodynamics AND the engine-- the Block 60 F-16 can (technically) supercruise due to the increased thrust of the -132 engine compared with older model F-16s which could not. If the Silent Eagle incorporates the -132 engine as well, or even higher thrust variants, there is nothing that prevents it from supercruising.

Overall, I'd say that this would be a good idea only if it could be retrofitted onto pre-existing F-15s-- I don't expect any more major orders for the F-15, no matter the improvements. If, on the other hand, the SE can be offered as a retrofit package, the USAF may well be interested since the number of Raptors they have now is pathetic and the F-35 is still in development. Boeing's ability to bring the F-18 E/F/G programme on time and on budget (more or less) would make this upgrade even more attractive.

Edit: Does anybody know where I can get a copy of the presentation? I can't seem to make an account on slideshare for whatever reason. Much obliged.

Edited March 18, 2009 by edwin3060

[edwin3060]

I was reading this site: http://www.aviationweek.com/aw/blogs/defen...68-f360585163ad

and as you can see from the attached picture, it looks like the V tail is grafted onto the same tail root-- and it looks larger than the original vertical tails, which should solve the yaw issue.

[miles316]

Sorry, Griffin? Do you mean Gripen? (I presume its the Swedish word for the same thing, though... ) I also assume you're referring to Boeings "Sonic Cruiser", which IIRC was killed off by fuel costs and airline disinterest (the spoilsports, I want to fly faster! ).

Also, I've just remembered where I've seen a fighter firing a missile from a FAST pack before - seems Boeing also has some Macross Plus fans on the payroll too...

Yes it was the Sonic Cruiser sorry it's been a while since I read that article.

Do you know if the conformal fuel tanks are integrated in to the F-15 structure, or are they removable.

A Gripen is a dragon right and a Griffin in a mythical creature with a lions body and a eagles head and wings? That is what I get for trusting spell check.

All of Sweden's fighters are named after dragons.

What fighter has a FAST pack?

[miles316]

It would basically be an F-22 sized F-35 with slightly better kinematic performance trading off against poorer all-round RCS, and the lack of a DASS.

One problem with the inlet is that it is variable geometry, whereas the F-22, F-35 and F-18 have fixed geometry inlets which can be optimized for stealth-- a truly stealthy inlet would have to be fixed, which would probably play hell with the engine performance of the F-15. Seeing as to how Boeing has said that the top speed of the Silent Eagle would not be affected, it may well be the case that the inlet can be 'fixed' in one position when stealth is required, and allowed to vary it's geometry when speed/cruise performance is required instead.

Also, Supercruise is due to both aerodynamics AND the engine-- the Block 60 F-16 can (technically) supercruise due to the increased thrust of the -132 engine compared with older model F-16s which could not. If the Silent Eagle incorporates the -132 engine as well, or even higher thrust variants, there is nothing that prevents it from supercruising.

Overall, I'd say that this would be a good idea only if it could be retrofitted onto pre-existing F-15s-- I don't expect any more major orders for the F-15, no matter the improvements. If, on the other hand, the SE can be offered as a retrofit package, the USAF may well be interested since the number of Raptors they have now is pathetic and the F-35 is still in development. Boeing's ability to bring the F-18 E/F/G programme on time and on budget (more or less) would make this upgrade even more attractive.

I thought that the F-15 and F-14 intakes are articulated was because of the technology of the late 60's when the they were originally developed was not as advanced as the F-18 F-16 which were developed ten years later and that is why they don't have variable geometry intakes.

I believe that the engines in the F-14 F-15 and F-16 are interchangeable so if the F-132 can fit in to the F-16 it can fit in to the F-15. I was reading a article in Vol 7,Nn 10 of Combat Aircraft about the decomisioning of the F-14 when the F-110 engines were removed they would be sent to the USAF for use in the F-16.

ing of the F-14 and they said that the F-110 engines in the F-14 were being distributed to F-16 units

[David Hingtgen]

The F-14 and F-15 intakes are how they are to go fast---you'll note they are MUCH faster planes than the F-16 and especially F-18. The F-16 and F-18 don't have variable intakes due to complexity/weight---they wanted those planes to be as light as possible. Few planes have variable ramps now, it's just not worth that last "0.whatever" mach. Ramps help an engine make more power at altitude, little more. The F-16 and F-18 have "old school" simple intake designs. The F-16's is like the F-8, the F-18's is like the F-5. Better to make the plane sleeker or the engine more powerful, than to add parts to the intake, for more speed at altitude. The Tornado has had its ramps deactivated and fixed in one position for years, with little effect on top speed. Wasn't worth the maintenance cost. (much like the F-14's glove vanes)

As for engines---the F-14's engines never went to anything else AFAIK. Their version of the F110 is unique. Now, many older F100 F-15 and F-16 engines do get handed down to even older ones as they're retired (-100's get -200's, -200's get -220's, etc). F110s are not very interchangeable---only the very latest F-15s can use it at all, and an F-16 is built to take either the F100 or F110, it cannot be changed without a MAJOR effort. (NASA is AFAIK the only place to ever have an F-16 change engine type---and that's because they custom-built a new intake)

The Silent Eagle's CFTs can be swapped out for normal Strike Eagle CFTs. (this likely means you could technically convert an F-15E to a Silent Eagle if you really wanted to---or more likely, convert an F-15DJ)

A little-commented-on feature snuck into the powerpoint is that the Silent Eagle has more chaff/flare dispensers---mounted in the tailbooms, similar to an F-16. (I wonder if the F-15I already has some there)

[miles316]

The F-14 and F-15 intakes are how they are to go fast---you'll note they are MUCH faster planes than the F-16 and especially F-18. The F-16 and F-18 don't have variable intakes due to complexity/weight---they wanted those planes to be as light as possible. Few planes have variable ramps now, it's just not worth that last "0.whatever" mach. Ramps help an engine make more power at altitude, little more. The F-16 and F-18 have "old school" simple intake designs. The F-16's is like the F-8, the F-18's is like the F-5. Better to make the plane sleeker or the engine more powerful, than to add parts to the intake, for more speed at altitude. The Tornado has had its ramps deactivated and fixed in one position for years, with little effect on top speed. Wasn't worth the maintenance cost. (much like the F-14's glove vanes)

As for engines---the F-14's engines never went to anything else AFAIK. Their version of the F110 is unique. Now, many older F100 F-15 and F-16 engines do get handed down to even older ones as they're retired (-100's get -200's, -200's get -220's, etc). F110s are not very interchangeable---only the very latest F-15s can use it at all, and an F-16 is built to take either the F100 or F110, it cannot be changed without a MAJOR effort. (NASA is AFAIK the only place to ever have an F-16 change engine type---and that's because they custom-built a new intake)

The Silent Eagle's CFTs can be swapped out for normal Strike Eagle CFTs. (this likely means you could technically convert an F-15E to a Silent Eagle if you really wanted to---or more likely, convert an F-15DJ)

A little-commented-on feature snuck into the powerpoint is that the Silent Eagle has more chaff/flare dispensers---mounted in the tailbooms, similar to an F-16. (I wonder if the F-15I already has some there)

I thought all engines used in US fighters with the exception of the F-18 GE-404 engines conform to the same umbilical connections fuel, Oil, and Electrical, mechanical allowing them to swapped. Are you a armchair military analyst like me, or do you actually have working knowledge of military technology.

[edwin3060]

The CFTs on the F-15 are certainly removable-- that is one of the advantages of the new Silent Eagle-- stealth CFTs if necessary, otherwise they can run with the normal CFTs and have the increased range.

Variable geometry intakes allow for an optimisation of airflow into the engine at the cost of increased complexity and weight-- the F-16 and F-18 have fixed intakes, but they are also limited to Mach 2.0-- and the intakes are optimised for subsonic cruising, IIRC, as are the intakes for the F-35. The F-22 is the only fighter with fixed intakes optimised for supersonic cruising. Since Boeing has stated that the top speed of the Silent Eagle is still Mach 2.5, either they managed to solve the RCS problem with variable geometry intakes, or they are ignoring it, since an intake redesign hasn't been mentioned.

The F100 vs F110 issue was because the F100 is a PW engine and the GE F110 requires much greater airflow, requiring the larger intakes you see from all Block 30/32 F-16s onwards-- but IIRC all subsequent F-16s (and F-15s) can accept either a F100 derivative or a F110 derivative without much issue---Saudi Arabia is re-engining their F-15S from the PW F100-229 to the GE F110-129C, for example. I imagine that if the new Block 60 F-16s can take the F110-132 instead of the -129, the Silent Eagle should be able to do the same without much issue (and gain around 13kN of thrust from each engine (131kN vs 144kN static)---woohoo!)

Edited March 18, 2009 by edwin3060

[David Hingtgen]

I thought all engines used in US fighters with the exception of the F-18 GE-404 engines conform to the same umbilical connections fuel, Oil, and Electrical, mechanical allowing them to swapped. Are you a armchair military analyst like me, or do you actually have working knowledge of military technology.

Armchair. But you sure can't swap the F100 and F110 around!

[miles316]

Armchair. But you sure can't swap the F100 and F110 around!

What are the difference between the F-100 and the F-110 besides performance does the F-110 have a bigger diameter or length?

Edited March 18, 2009 by miles316