USAF Actually Buying F-15Xs?

originally posted by: Zaphod58
a reply to: Tempter

Both. The vast majority of the original F-15 fleet was delivered with longerons that were cut wrong. In 2007 the entire fleet was grounded three times, after an aircraft broke apart during ACM. The problem was traced to faulty longerons that were delivered cut too thin. Somewhere around 160 aircraft were retired because of it.

The F-15 was originally designed with an 8,000 hour life cycle. In 2006, something like 90% of the aircraft flying had used 95% of that life cycle or more. There were aircraft that were past that point and still flying. The Air Force did fatigue testing and a SLEP, and extended it to something like 12,000 hours. We're now approaching that point. In most aircraft, the limiting factor in life cycle is the center wing. So to continue to fly them, they're going to have to SLEP that portion of the aircraft, and if they want to add more capabilities, such as adding two more missile racks to the wings, they need to replace the wing with a new type of wing that was developed for the F-15QA.

So somewhere in the stress testing they figured that the center wing was the limiting factor to 12k hours? or something beyond that i would imagine?

I wonder what other considerations came in to play.

a reply to: Tempter

All aircraft undergo a comprehensive fatigue test. They usually test them to the equivalent of three lifetimes of flight hours. In 2011, the F-15 entered a worldwide fatigue test program that was set to extend the life cycle to 32,500 hours for the F-15E, and 18,000 hours for the C/D. The F-15 has several areas that are being watched, mostly around the wing area, several of which are related to the skin on the wing. That's not the only area though, as there was a failure of a vertical fin in 2014 while in a high speed dive, that put an F-15 into the Gulf of Mexico.

The F-35 recently completed its comprehensive fatigue test in the UK. The test article was sent to the US to undergo extensive analysis and tear down. It was tested to three or four complete life cycles with no problems, and no major obvious issues. The complete tear down and analysis will determine its ultimate life cycle.

Still wondering if this is a test buy which may result in a follow on order since the F-22 line can't easily be brought up to speed. Also curious about the sensor suite it'll have..

originally posted by: anzha
This is such a stupid idea.

about.bgov.com...

Buying a 100 Mil US-$ legacy jet to transition Guard units for a practially obsolete mission is not stupid, its borderline treasonous at this point.
Maybe there is a chance the new SecDef will have different priorities. NOT.
Or someone Congress will turn out to be bought by Lockheed instead of Boeing and be able to sink this proposal.

But i'm looking forward to see the CBOs reasoning as to why this is a brilliant move and will lead to huuuge cost savings.

a reply to: dasman888

Perhaps you can read up on the actual head to head scenarios that have been done where the F-35 was pretty much unstoppable against the F-15. Even when a dogfight is forced the F-35 holds it's own pretty well.

You seem to expect the F-35 to be perfect and if it's not then it's garbage.

a reply to: Masisoar

It only makes sense as a pilot process for a larger follow-on order. But a large follow-on order makes no sense itself. You could argue the merits of Boeing's previous offer to customers of -X upgrade packages, zeroing out old airframes, upgrading systems, the various wings, canted tails, conformal options, ram treatments,etc all previously offered for $20-40M. Not the way I'd go, but It has merits.

Small runs of new build X's at even $65M, nevermind this figure, is just a profoundly stupid way to spend money. So stupid even the USAF isn't interested. Takes civilian leadership at the Dept level to get this stuff.

This is all about helping Boeing keep the line open. Dumb.

Money, money huh?

Surely the only consideration necessary is the cost incurred by the crater when it inevitably hits the ground.

a reply to: SlowNail

Of course it's inevitable. That's why there are still a few hundred original F-15s flying that have never come close to hitting the ground.

a reply to: Zaphod58
Zaph I could be wrong but I think SlowNail was referring to the the kind of crater an F-15 would make if it went up against an S-400 as opposed to spending the money on something like an F-35.

a reply to: Zaphod58
I'm betting the F-35 ends up with a 20,000hr service life fairly early on. Possibly ending up in the high twenties to low thirties, similar to where the Beagle's are heading.

I've been reading up on the F15X. It makes lots of sense. It has also been explicitly said by everyone involved that it has nothing to do with the F35.

This is a useful measure to get a workhorse that can fly for 80 years, be plugged right into existing crews and infrastructure with no added cost as well as augment anything else in our arsenal.

Upgrading F15 C/Ds, only to retire them shortly after is absurd and wasteful.

This makes use of developed and paid for technologies that export clients funded and USAF planned upgrades which would not be used otherwise.

The F15X is perfect for coastal defense and patrol missions. Adding all that workload to an already busy fleet of F35s would reduce our presence in other areas that the F35 is absolutely needed.

Allied or unchallenged airspace does not need F35s.

In fact, showing a deterrent instead of hiding your presence is sometimes preferred. Making an enemy bomber change its course is better than shooting it down after it fires supersonic cruise missiles or drops its bombs. And so on.

a reply to: tadaman

How does that make sense when this is more expensive than getting F-35 for this job. No one is saying thin out the F-35 fleet. They are saying get more because it would cost less for a better platform.

originally posted by: tadaman
I've been reading up on the F15X. It makes lots of sense. It has also been explicitly said by everyone involved that it has nothing to do with the F35.

Unfortunately, it doesn't make much sense. Not because the Eagle isn't awesome (it is) or that the upgrade wouldn't be a welcome capability (it would). But the costs and opportunity costs make zero sense. It has everything to do with the F-35 program, LRS-B, and to a lesser extent LCAA/"Loyal Wingman"/Have Raider X and whatever PCA becomes. Because those are the programs that are critical succeed, and the budget is limited. Every dollar you spend here is a dollar taken from those programs.

The math hasn't changed since Boeing first floated the idea. It's why the Air Force took a hard pass despite a (well-deserved) love affair with the Eagle. Let's ignore the $100M per price tag for the first 12. A lot of that is one-time, non-recurring costs associated with start up and high-prices from suppliers based on small lot production. Let's use Boeing's proposed $65M price tag instead.

originally posted by: RadioRobert

But the reasons to recap with an F-15X instead of increasing the F-35 buy would all be $$$, and the numbers don't look very promising.

Made up requirements: you want to retire extra airframes and replace 400 older legacy airframes as it an interim for PCA.

Options: Buy 400 new Eagles? Or for the same money, you can expand your F-35-buy by 325 (or more with economies of scale) airframes?

$65M x 400= $80M x 325

And when you can cut the entire F-15C/D/X lines from maintenance, training, spares, supplies and replace them with more F-35's and streamline, you see even bigger savings (or alternatively, even more F-35's for the same money).


If you could rehab and refit old Eagles for $30-40M, then numbers look a lot better for that option because you are right, you absolutely don't need an F-35 for many missions. You just need a truck. But Boeing is trying to keep the lines open on legacy projects because they don't have much in the hopper for future production so they aren't pitching that. Once the lines close, they won't come back. Even limited runs to keep them open leave a chance for follow-on orders. So it's all about the keeping them open at any cost right now.

Unfortunately for Boeing, right now the maths suck. I don't think you can squeeze the cost of even a 400-unit run on a big twin-engine fighter enough to make the numbers work in it's favour.

Unless you expect a shooting war with a near peer in the next five years, this plan sucks.

It even sucks as corporate welfare because they could simply order a similarly large number of $60M EA-18's for the Navy/Marines despite its shortcomings and form land-based expeditionary squadrons to actually address the USAF/USN short-term need for stand-in jamming from a tactical platform in the sandbox while cycling existing units back to the fleet.

a reply to: thebozeian

Right now, based on the early analysis of the fatigue frame, they're looking at around 24,000, so don't be surprised if it turns out you're right.

a reply to: OccamsRazor04

Yet we can't afford an all stealth fleet and we can't afford to NOT patrol our homeland.

The C/D models are fulfilling a job already. One they are ready to tap out from. What will replace them? F35s we don't have in significant numbers?

It would be more of a waste to upgrade the old planes if we have to retire them for safety reasons shortly after.

This is the best of both worlds. We get an arsenal ship that will have a flat flyaway price. One that can fly for 80 years more or less.

I understand the reasoning behind wanting more JSFs. Thing is we can't ignore other needs.

Using F35s for all possible missions, even those other planes could do for cheaper per flight hour and in terms of maintenance, is also going to take money away from F35 funds.

How would you eliminate a truck and a tent suspected of being enemy fighters? Use an expensive plane and ordinance to take out a soft target in safe airspace?

That's absurd.

We are going to need nonstealth planes for many types of missions.

Penetrating heavy air defenses is not a role an F15 can fill. Cool. F35s can lead the way. When they run out of missiles, they can light up targets for planes like these.

In the Pacific at least, these can be useful for more than coastal defense.

Edit to add:
If we ever need to send an F35 in beast mode, with all external weapon hardpoints bristling with missiles, why not just send an F15 since stealth is not a factor in that situation?

The F15 is faster and is more maneuverable than an F35 as well as it having more weapons and options for more types of weapons.

If stealth and other abilities aren't a factor in some situations then why not use a proven tool?

I see it as making sense.

a reply to: tadaman

The problem is that spending $65-100M on an airframe that won't be relevant in 10-12 years means that we ARE ignoring other capabilities. That money is coming from somewhere, so where do we pull it from? We currently need a new system to replace the E-8C, to put new engines on the B-52, to buy the B-21, buy the JSF, spending for the T-X buy, development of the PCA, pretty soon a new E-3 platform, the KC-46 buy, two new tanker programs.... So what do we cut to buy an airframe that we'll be getting rid of in less than 20 years?

The F-15 is a bad platform for the Pacific. You need something with a lot of range, that can minimize support needs. That's one reason PCA is looking at being something closer to B-58 size and less of a fighter platform. You want something that can be a persistent presence in the target area, and less of an in and out drag your tanker with you platform.

a reply to: thebozeian

Nah, I was just being a childish ass.

It was a jibe at the thought of buying more jets without being able to field the ones you got.

It was just silly and inflammatory really.

I know you guys will defend it to death, but your planes are overkill.

a reply to: SlowNail

And the world will be so much safer if we just get rid of them, and give up our military. Then everyone else will see the error of their ways and we'll suddenly be at peace and everyone will get along.

a reply to: Zaphod58

Yes. Maybe not America, but the world indeed.

a reply to: SlowNail

And how do you propose that we convince the world to do that? Ask really nicely? As long as resources are an issue, there will be a need for a military. Unless you can come up with a way to convince the world to suddenly get along and stop competing for resources it's not going to happen any time soon.