F-15X: USAF Seems Interested

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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mixelflick

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Unread post21 Aug 2020, 18:15

F-15EX[/quote]

-132s would be better. :twisted:[/quote]

I thought they were both 32,000 lb st thrust engines[/quote]
The -129/-229 engines are ~29k thrust. The-132/-232 are ~32k thrust.[/quote]

Going to 29,000lbs is still going to give about a 10,000lb thrust increase, vs. what F-15C's fly with today. The real question being, how much weight will the F-15EX gain?

One would think it might lose some weight, going with a FBW design. Not sure about the avionics, but they generally get lighter/smaller as technology marches on - not heavier. There are no plans I'm aware of to carry more internal fuel. There does exist the possibility it'll fly with CFT's regularly, although I'd say that's less likely than originally thought. USAF reportedly didn't opt for the "quad packs" allowing each inner wing pylon to carry 4 missiles, vs. the current 2, so that indicates no regular CFT carry too IMO.

I can only imagine its performance if weight stays the same, with those powerful new motors. And who knows? Now that the engines won't be a sole source contract, GE might even up their game. I'd sure like to get the proposed combat configured air to air weight, but then again it might be classified.
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milosh

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Unread post21 Aug 2020, 18:42

sprstdlyscottsmn wrote:
marauder2048 wrote:I'm really baffled at the resistance to the suggestion that the Russians achieved
Super Hornet scale, in relative terms, signature reductions.

especially when that means getting a Flanker RCS to legacy Hornet levels down from F-15 levels.


If you use RAM and composite you can reduce RCS noticeable which Sukhoi did, this isn't some forum info but official info, you can find that in any Su-35 brochure.

Same can be done with F-15EX but there isn't any idication that was done, and that would need testing too.

And USAF wouldn't want some Silent Eagle because politicians can say look it is stealthy so why not buy more instead of F-35?
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mixelflick

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Unread post23 Aug 2020, 16:43

No "Silent Eagle" was ever going to be stealthy, at least in the way the F-35 is. With the F-35, you have an aircraft that can survive and neutralize IADS threats and hit its targets. The best any Silent Eagle would have been able to do it get a single munition off, probably an AMRAAM and that's IF the fight only involved it's frontal radar signature. Highly, highly unlikely IMO. I don't see a single 4th gen fighter that can be modified to bring it even close to LO standards, let alone VLO. And the Eagle would probably be the one with the worst starting point. And no, the Super Hornet doesnt' count.

Although... you can fool Congress into buying fairy tales, I'll give you that. Boeing did it with the Super Hornet..
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wrightwing

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Unread post23 Aug 2020, 20:51

marauder2048 wrote:
wrightwing wrote:
You've provided Russian claims, assumed the best about Flankers, and assumed the worst about the F-15EX.


The evidence out there only supports reduced signature Su-35s; it does not in any way support reduced signature F-15EX.

I'm really baffled at the resistance to the suggestion that the Russians achieved
Super Hornet scale, in relative terms, signature reductions.

Given uncertainties over PAK-FA it would have made sense for them to have crash coursed signature
reductions for the Flankers series.

Well given that Su-30s and earlier have an even larger RCS than F-15s, and Su-35s have significantly fewer changes than Super Hornets vs Hornets, call me skeptical about how much reduction they've achieved. Even F-16s only went from ~3m^2 down to ~1m^2, after Have Glass, etc.... Super Hornets had shaping changes, blockers in inlets, planform alignment, etc.... To go from >20m^2 down to 1 to 3m^2 without any shaping/blockers, etc.... sounds very optimistic, regardless of how much RAM they slapped on.
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marauder2048

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Unread post23 Aug 2020, 23:33

wrightwing wrote:
marauder2048 wrote:
wrightwing wrote:
You've provided Russian claims, assumed the best about Flankers, and assumed the worst about the F-15EX.


The evidence out there only supports reduced signature Su-35s; it does not in any way support reduced signature F-15EX.

I'm really baffled at the resistance to the suggestion that the Russians achieved
Super Hornet scale, in relative terms, signature reductions.

Given uncertainties over PAK-FA it would have made sense for them to have crash coursed signature
reductions for the Flankers series.

Well given that Su-30s and earlier have an even larger RCS than F-15s, and Su-35s have significantly fewer changes than Super Hornets vs Hornets, call me skeptical about how much reduction they've achieved. Even F-16s only went from ~3m^2 down to ~1m^2, after Have Glass, etc.... Super Hornets had shaping changes, blockers in inlets, planform alignment, etc.... To go from >20m^2 down to 1 to 3m^2 without any shaping/blockers, etc.... sounds very optimistic, regardless of how much RAM they slapped on.


The Flankers always had lower RCS than the F-15s. That's what motivated ATF in the first place.
If you don't like the HAVE GLASS or Super Hornet analogies how about B-1A -> B-1B?
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Corsair1963

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Unread post24 Aug 2020, 05:06

marauder2048 wrote:
The Flankers always had lower RCS than the F-15s. That's what motivated ATF in the first place.
If you don't like the HAVE GLASS or Super Hornet analogies how about B-1A -> B-1B?


You have a credible source that says the Flanker Series has a lower RCS than the F-15???
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marauder2048

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Unread post24 Aug 2020, 05:49

Corsair1963 wrote:
marauder2048 wrote:
The Flankers always had lower RCS than the F-15s. That's what motivated ATF in the first place.
If you don't like the HAVE GLASS or Super Hornet analogies how about B-1A -> B-1B?


You have a credible source that says the Flanker Series has a lower RCS than the F-15???


https://www.cia.gov/library/readingroom/docs/DOC_0000498135.pdf

This is a 1984 document.

Based on RCS reductions to Blackjack, the CIA was estimating that Soviet fighters like
the Su-27 would receive RCS treatments that could reduce RCS by a factor of 10
to <= 1 m^2. Which would put the baseline in the low teens as an upper bound.

That's smaller than any RCS estimate I've ever read for the F-15.

And tellingly, the CIA estimate for the lower-bound for an RCS retrofit Flanker series
is "a fraction of a square meter."

So 30 years later, it's not unreasonable to assume that the Su-35 has met this prediction.
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wrightwing

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Unread post24 Aug 2020, 07:14

marauder2048 wrote:
Corsair1963 wrote:
marauder2048 wrote:
The Flankers always had lower RCS than the F-15s. That's what motivated ATF in the first place.
If you don't like the HAVE GLASS or Super Hornet analogies how about B-1A -> B-1B?


You have a credible source that says the Flanker Series has a lower RCS than the F-15???


https://www.cia.gov/library/readingroom/docs/DOC_0000498135.pdf

This is a 1984 document.

Based on RCS reductions to Blackjack, the CIA was estimating that Soviet fighters like
the Su-27 would receive RCS treatments that could reduce RCS by a factor of 10
to <= 1 m^2. Which would put the baseline in the low teens as an upper bound.

That's smaller than any RCS estimate I've ever read for the F-15.

And tellingly, the CIA estimate for the lower-bound for an RCS retrofit Flanker series
is "a fraction of a square meter."

So 30 years later, it's not unreasonable to assume that the Su-35 has met this prediction.

There was nothing in that document to suggest that Su-27s and Su-30s ever had lower RCS figures than F-15s, much less achieving 1m^2 after applying RAM. Su-35s still have no planform alignment, they have exposed engine blades, large vertical stabilizers, a decidedly bulbous IRST,.etc... If you look at all the changes necessary between the Super Hornet and legacy Hornet, the Su-35 hasn't even come close in comparison.
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marauder2048

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Unread post24 Aug 2020, 07:30

From the document (Page 12)

The Soviet aircraft currently in development have no outward signs of RCS reduction, but we
believe some of them will have features that will significantly reduce their RCS.
This is true for the SU-27 and the MiG-29


The order of magnitude reduction for the B-1B did not require planform alignment and
none of the techniques the CIA identified as retrofit techniques involve it either.

The CIA states that the expected order of magnitude reduction retrofits would produce
a fighter with fractions of a square meter RCS. So pick your fraction and solve for the
original RCS.
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charlielima223

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Unread post24 Aug 2020, 08:01

marauder2048 wrote:From the document (Page 12)

The Soviet aircraft currently in development have no outward signs of RCS reduction, but we
believe some of them will have features that will significantly reduce their RCS.
This is true for the SU-27 and the MiG-29


The order of magnitude reduction for the B-1B did not require planform alignment and
none of the techniques the CIA identified as retrofit techniques involve it either.


I would say that CIA document is an overly "optimistic" guestimation on Soviet RCS reduction measures at the time. You mention the B-1B. Aside from having a very well blended body design, the biggest factor leading to its reduced radar signature head on was its redesign of its engine intake. There is no information out there stating or hinting of Flankers of any variant with any redesign to its intakes or any part of its outermold structure.
Any claim regarding older Flankers having a smaller RCS than the Eagle or Su-35 RCS close to a clean Rhino needs to be taken with a liberal serving of salt.
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marauder2048

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Unread post24 Aug 2020, 08:16

charlielima223 wrote:
marauder2048 wrote:From the document (Page 12)

The Soviet aircraft currently in development have no outward signs of RCS reduction, but we
believe some of them will have features that will significantly reduce their RCS.
This is true for the SU-27 and the MiG-29


The order of magnitude reduction for the B-1B did not require planform alignment and
none of the techniques the CIA identified as retrofit techniques involve it either.


I would say that CIA document is an overly "optimistic" guestimation on Soviet RCS reduction measures at the time. You mention the B-1B. Aside from having a very well blended body design, the biggest factor leading to its reduced radar signature head on was its redesign of its engine intake. There is no information out there stating or hinting of Flankers of any variant with any redesign to its intakes or any part of its outermold structure.
Any claim regarding older Flankers having a smaller RCS than the Eagle or Su-35 RCS close to a clean Rhino needs to be taken with a liberal serving of salt.


The CIA was projecting what RCS reductions could be retrofitted to fighters by the mid-1990's
and trying to bound what radar cross sections Soviet retrofit fighters might achieve.

The assumption in the document is that the Flanker had some RCS reductions that were not
evidenced by planform alignment or anything OML related.

The document shows bounds for the Blackjack and indicates a lower bound for
fighters in the sub-square meter range.

The B-1B is proof that redesign of key hotspots within the same OML can translate
into an order of magnitude RCS reduction.

The Su-35 is a redesign of the Su-27 that retains the same OML.
The Russians are claiming RCS reductions as a consequence of this redesign.
The CIA lower-bound for the techniques the Russians are claiming is sub m^2.

Take the upper-bound instead; it's still very low single digit.
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Corsair1963

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Unread post24 Aug 2020, 09:21

AFMC: Air Force Not Bound to 144 F-15EXs


Aug. 21, 2020 | By John A. Tirpak

The Air Force doesn’t have to buy all 144 Boeing F-15EX aircraft covered by last month’s major contract award and can terminate the program simply by not ordering any more of the jets, according to Air Force Materiel Command.

In response to a series of email queries from Air Force Magazine about whether USAF has any off ramps to buying 144 F-15EXs over the next 15 years—especially given that the service is also buying fifth-generation F-35s and will soon start buying the even more advanced Next-Generation Air Dominance airplane—AFMC noted that the nearly $23 billion contract awarded to Boeing is of the “indefinite delivery/indefinite quantity” type. It said USAF has not entered into an agreement to buy all the planes the contract could potentially cover. The $1.2 billion actually spent in the July 13 contract covers just the first eight test aircraft and development.

The contract is “structured to accommodate annual delivery orders for each aircraft lot and required product support elements,” an Air Force Life Cycle Management Center spokesman said. “Until the orders for each lot are awarded, the government has no financial liability for those aircraft” and supporting materiel.

“Thus, the most straightforward way for the Air Force to reduce the total procurement quantity is simply to stop placing new delivery orders,” the spokesman said.

If the Air Force wanted to quit the contract in the middle of a delivery cycle, it would be at the government’s convenience, and Boeing could recover “allowable costs and reasonable profit on work performed under the contract.”

The deal provides up to $22.89 billion for F-15EX work, but the dollar figure was described by a USAF spokeswoman as an “upper limit.” The contract actually allows up to 200 airplanes to be bought, with deliveries through 2035. The jets are supposed to replace aging F-15C/Ds, but the Air Force recently revealed that it hasn’t decided whether it will also tap the F-15EX to replace its fleet of F-15Es, which age out in about 2030.

In documents recently released by USAF justifying the sole-source contract to Boeing, the Air Force said the F-15C/D fleet is rapidly aging beyond its planned service life, and retiring the jet without a replacement in hand would leave the service short of the capacity it needs to fulfill the National Defense Strategy.

The Pentagon has been criticized for not simply buying more F-35s instead of buying “new-old” F-15s, as the Air Force has described such a move for the last 20 years. Outgoing head of Air Combat Command Gen. James M. “Mike” Holmes, in an Aug. 14 AFA live-streaming event, said the F-15EX program is the result of the Office of the Secretary of Defense trying to fix a near-term shortage of USAF fighter capacity.

The Cost Assessment and Program Evaluation shop (CAPE) examined the mix of fourth- and fifth- generation fighters for all the services, and decided USAF needed at least 48 fifth-gen F-35s per year to “compete” with China, Holmes said. But at that rate, the USAF fighter inventory’s average age still continued to increase. The Air Force calculated that it needed 72 fighters a year to really drive down the average age of the fleet, which would in turn reduce the cost of sustaining it.

“They came back and said, ‘Okay, we understand that math, but we still have our fourth-/fifth-gen mix equation, so if you’re going to buy additional airplanes, we want to buy fourth-gen,” Holmes said. The advantages for USAF, he added, are that new F-15EXs can make use of facilities, training, and ground support gear very similar to that of the F-15C/D, and USAF can field it up to three years faster than if it was buying all F-35s, Holmes said

“So, … Congress has given us some of both,” Holmes said, buying some F-35s “and then buying some F-15EXs.”

In addition to the F-35 and NGAD, the Air Force is also planning to acquire Low-Cost Attritable Aircraft in the coming decade, along with service life extensions and capability upgrades for the A-10 and F-16. The NGAD will likely be the product of USAF acquisition chief Will Roper’s “Digital Century Series” idea, which will field a number of advanced aircraft types in quantities of less than 100 each. It isn’t clear when the first of those might become available, but USAF has said it needs to field new platforms by around 2030 to assure control of the air. Holmes has said USAF will likely need two types of air dominance airplanes in the 2030s: One with long range for the Indo-Pacific theater, and one with shorter range more suited to the distances in Europe and the Middle East.

The Air Force has allowed that with flatter budgets anticipated in the coming years, the full range of air dominance platforms now planned may not all be affordable.

https://www.airforcemag.com/afmc-air-fo ... 4-f-15exs/
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mixelflick

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Unread post24 Aug 2020, 18:01

I'll say...

No way 2 new fighters are going to be procured.. one for the Middle East/Europe and the other for the Pacific Theater. I'll be shocked if USAF and USN are able to simultaneously procure PCA type fighters, much less USAF having 2 of their own.

As for the F-15EX, I'd rather see them either go all in and buy 200+, or not do it at all. A small handful of F-15EX's isn't going to help anyone. A large fleet, complete with enough to replace the Strike Eagle inventory? Possible, especially if hypersonics mature as expected..

In other news, I found this Swiss legacy Hornet demo interesting..

https://www.youtube.com/watch?v=Nf5A13atLHQ&t=76s

Any way you slice it, those are "supermaneuverable" maneuvers - without the added weight and cost of thrust vectoring engines. Same deal with the F-35, just to an even greater extent. Appears to me that if you have a good FBW system married to some real whizbang flight control software, you can certainly pull it off.

Which begs the question... will the F-15EX be capable of the same?
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marauder2048

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Unread post24 Aug 2020, 21:40

mixelflick wrote:I'll say...
As for the F-15EX, I'd rather see them either go all in and buy 200+, or not do it at all. A small handful of F-15EX's isn't going to help anyone. A large fleet, complete with enough to replace the Strike Eagle inventory? Possible, especially if hypersonics mature as expected..



Given that the Air Force has just elected to replace an F-15C unit with F-35s it's clear that the
cost/timeline tradeoffs for F-15C units converting are unclear..
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Corsair1963

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Unread post24 Aug 2020, 23:57

Most of the ANG Bases have been pushing hard to get the F-35A instead of the new F-15EX. With Jacksonville finally succeeding....


Yet, I am more interested is see what happens with the two remaining F-15C's Squadrons operated by the USAF. Which, are based at Lakenheath (UK) and Kadena (Okinawa, Japan)....

:|
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