F-15Es Standing in for Cs

[Rex]

I don't know if this has already been posted, but I thought it was interesting:

https://www.thedrive.com/the-war-zone/f-15e-strike-eagles-now-flying-without-conformal-fuel-tanks-on-air-defense-missions

 

Correct me if I'm wrong, but flying the E configured like a C would result in a far more powerful plane than the C has ever been:

 

F-15E Empty Weight (with empty conformal tanks) = 31,700 =lbs

F-15E Wet Thrust = 58,320 lbs

 

F-15C Empty Weight = 28,800lbs

F-15C Wet Thrust = 47,540lbs

 

F-15E Empty T/W = 1.84

F-15C Empty T/W = 1.65

 

Granted these are EMPTY weights, and those ratios come  down fast once you start adding fuel, but still, that would be an absolute beast.  A stripped E would spank a C like it had stolen something.

[GGTharos]

Sure, I'll correct you:

The F-15E with CFTs weighs in at some 36400lbs empty, IIRC.  It also has massive drag because of the CFTs compared to the F-15C.

The F-15E has a far heavier nose, and that causes issues with AoA performance, CFTs or no CFTs.

The F-15E's engines eat fuel a lot faster if you want more of that thrust.

F-15E pilots don't do A2A unless it's against low threats, or if for some reason the F-22's and F-15Cs, and in some cases F-16's are not available.   And at this point, F-35s will outperform them just due to stealth.

Think for a moment:  The USAF never re-engined the F-15C after the -220s.  There's a reason for that, given that they've received other significant upgrades.

 

But I come back to the most important thing:   F-15Es do not take over F-15C duties because they do not train for them - basically if you're using F-15Es for front-line A2A you're desperate.

Edited July 11, 2023 by GGTharos

[munckmb]

1 hour ago, Rex said:

A stripped E would spank a C like it had stolen something.

Never

[Theodore42]

Interesting article, it seems the F-15EX is not going to have the CFTs but maybe they'll flex to them if needed. The article also pointed out that F-15Cs have been deployed with CFTs in Iceland and Alaska, implying that the F-15E's mission may require versatility when it comes to CFTs rather than "the F-15E is a bomber PERIOD, FULL STOP, END OF LINE."

The Pentagon is in a weird place when it comes to air power. They're just now getting the F-35 deployed, the fantasy project of politicians using a cookie cutter solution to every branch of the Military's air superiority problem. The other side of the coin is that the face of war is changing. No more skirmishes but now militaries are preparing for large scale warfare. Does the F-15E have the ability to penetrate an expansive, modern air defense network operated by a professional military? The cookie cutter solution of the F-35 is stealth. It can, in theory, overcome air defense radar to be highly effective in a combat.

While some have bought into the F-35 theory, others have not. The A-10, scheduled to be retired in the early '90, then the late '90s, then it was upgraded and scheduled to retire again (and then again I think?).... NOW it is scheduled to be rewinged by 2030 to utilize modern weapons. So a general somewhere thinks he's going to get more out of the A10 than he is out of the F35. The F-18 got upgraded to the Superhornet. The F-16 has a million variants that just keep coming out, and the subject of the article, the F-15EX, is an up to date Strike Eagle. These airframes express the peak expression of decades of research and if you can upgrade their power and electronics you have a sure thing. Generals like that. MAYBE a fleet of stealth aircraft can overcome modern air defenses. But if not there is a backup plan.

The article reports that the F-15EX can right now carry 12 AMRAAMS but experimental pylons are being tested to carry up to 16 AMRAAMS. IMO this implies that the strategy of US air power is to use the stealth F-35 for the majority of ground attack and the F-15EX for BVR ACM. They don't need the CFTs because they aren't penetrating deep into enemy airspace to attack high value ground targets. But they CAN be converted to a bomber in short order should the need arise. (Maybe a squadron of F-16s have been doing SEAD strikes in the area for a few days.)

Thanks for posting the article. I feel like the Pentagon has been going all in on the F-35 with one hand but grasping at the legacy airframes with the other. But seriously, when in warfare has deducing a single solution out of the ether to go with a novel, untested strategy gone well? Armies haven't fought on this Earth for real in 75 years. The generals are right to grasp at their legacy airframes and I'm glad to read there seems to be a lot of thought behind it.

[Nodak]

If you haven't noticed in every photo of an E with the tanks off, the fuselage missile mount points are smoothed over, because they were never factory incorporated.  You just lost half your missile attachment points, who has the better odds now.  

[Theodore42]

11 minutes ago, Nodak said:

If you haven't noticed in every photo of an E with the tanks off, the fuselage missile mount points are smoothed over, because they were never factory incorporated.

You must have missed the photo of the new inboard quad pylon.

QUAD DAMAGE!!!!

Those F-15EX guys are going to be playing airquake for real now.

[GGTharos]

14 minutes ago, Theodore42 said:

Interesting article, it seems the F-15EX is not going to have the CFTs but maybe they'll flex to them if needed. The article also pointed out that F-15Cs have been deployed with CFTs in Iceland and Alaska, implying that the F-15E's mission may require versatility when it comes to CFTs rather than "the F-15E is a bomber PERIOD, FULL STOP, END OF LINE."

Different conformals for different purpose.   The Icelandic and some of the Alaskan Eagles needed legs over pretty much everything else.   Those CFTs do not have the A2G stations, and those F-15s do not have the weight issues that the strikes do when it comes to air to air combat.

The EX is a replacement for the E - I suppose it'll be interesting if it ends up replacing the C's for a certain time, but that'll come to an end as soon as NGAD is put in place.

Edited July 11, 2023 by GGTharos

[Njinsa]

@GGTharos - empty 34600, type 5 CFT (empty) about 4400, according to 1993 dash1 (-229 engines).

Edited July 11, 2023 by Njinsa

[GGTharos]

I just checked mine (from 1993), basic empty operating weight with CFT and crew at 37500.   This would be the weight at which the F-15Cs lowest 'clean' chart is presented.

Each CFT for the F-15E weighs in at approximately 2000lbs.

[bfr]

Probably important to also not assume that because E can be configured to perform roughly the same role as C (which by the sound of it is mostly just air patrol/interception work) that E must be at least the equal of C in all aspects. Sure, it can probably do a perfectly adequate job of the task in hand but even the article suggests they are being pressed into this role because the C has too many miles on the clock rather than because the E is 'better'. 

[strikeeagle]

10 hours ago, GGTharos said:

Sure, I'll correct you:

 

But I come back to the most important thing:   F-15Es do not take over F-15C duties because they do not train for them - basically if you're using F-15Es for front-line A2A you're desperate.

 

Where did you get this info from? 

[Tenkom]

I was feeling extra nerdy today so I did a little in-game experiment.

Goal: Working out how much drag and thrust these 2 planes have(F15C and F15E).

I had to limit myself here since this could get incredibly complex very quickly. So I decided to determine thrust and drag at approximately 830km/h across the ground at roughly 2900 meters.

Method: Screen capture recording acceleration and deceleration between 814.88km/h to 851.92km/h ground speed. Both planes clean, fuel adjusted so both planes have the same mass at 18140kg and fuel usage turned off so the mass is constant.
I made some assumptions. Drag is approx. constant across the speed range and thrust is approx. constant across the speed range.
Apply Newton's law. F=ma

Results:

F15C:
Drag: 39kN
Thrust(full AB):  173kN

F15E:
Drag: 51kN
Thrust(full AB): 203kN

How accurate this is depends on how close to (virtual)reality my assumptions are of course.

Conclusion: F15E has more thrust but also more drag. Basically what we already knew. Time well wasted

[quailman84]

17 hours ago, Nodak said:

If you haven't noticed in every photo of an E with the tanks off, the fuselage missile mount points are smoothed over, because they were never factory incorporated.  You just lost half your missile attachment points, who has the better odds now.  

 

Missile ejectors are clearly visible on fuselages of these non-CFT strike eagles. Photos elsewhere do show them in place, too. The article linked in the OP also makes clear that F-15E's are being tasked with A-A duties. While not their primary role, they do train for this and, although rare, they are in fact being tasked in this. An SE without CFT should have an empty weight in the neighborhood of 33K lbs. Still some 4K heavier than a C. Weights quoted in other posts are still including CFTs.

[strikeeagle]

1 hour ago, quailman84 said:

 

Missile ejectors are clearly visible on fuselages of these non-CFT strike eagles. Photos elsewhere do show them in place, too. The article linked in the OP also makes clear that F-15E's are being tasked with A-A duties. While not their primary role, they do train for this and, although rare, they are in fact being tasked in this. An SE without CFT should have an empty weight in the neighborhood of 33K lbs. Still some 4K heavier than a C. Weights quoted in other posts are still including CFTs.

Yes -- If the jet flies w/out CFT's, LAU-106's are installed.  That airplane is perfectly capable of operating in a full A/A environment.  Our crews train for A/A.  The first couple weeks or so of a B-course is all A/A (w/CFT's, no pods).

[KlarSnow]

Half the training time of strike eagles is air to air. And we have and are tasked quite frequently, and more in recent times with air to air roles. If the mission doesn’t specifically require a precision strike role, F-15Es will load up 7x1 or 6x2 just like a C model and perform air to air as a primary mission. 

[Cab]

11 hours ago, quailman84 said:

 

Missile ejectors are clearly visible on fuselages of these non-CFT strike eagles. Photos elsewhere do show them in place, too. The article linked in the OP also makes clear that F-15E's are being tasked with A-A duties. While not their primary role, they do train for this and, although rare, they are in fact being tasked in this. An SE without CFT should have an empty weight in the neighborhood of 33K lbs. Still some 4K heavier than a C. Weights quoted in other posts are still including CFTs.

 

8 hours ago, KlarSnow said:

Half the training time of strike eagles is air to air. And we have and are tasked quite frequently, and more in recent times with air to air roles. If the mission doesn’t specifically require a precision strike role, F-15Es will load up 7x1 or 6x2 just like a C model and perform air to air as a primary mission. 

Nice to see people with apparent first hand knowledge dispelling some of the long held myths on this topic.

 

 

Edited July 12, 2023 by Cab

[Cab]

9 hours ago, strikeeagle said:

Yes -- If the jet flies w/out CFT's, LAU-106's are installed.  That airplane is perfectly capable of operating in a full A/A environment.  Our crews train for A/A.  The first couple weeks or so of a B-course is all A/A (w/CFT's, no pods).

I intended to include this quote as well

[Rex]

On 7/10/2023 at 9:01 PM, GGTharos said:

Sure, I'll correct you:

The F-15E with CFTs weighs in at some 36400lbs empty, IIRC.  It also has massive drag because of the CFTs compared to the F-15C.

 

 

I'll admit that my sources are rather lame, but I'm not all that informed on these matters, so I follow the path of least resistance.

Wikipedia shows 31,700lb, but ... yeah ... Wikipedia is probably not an excellent source.

That said, it's not like the CFTs are gigantic parachutes.  I mean, I get it, extra weight and surface area, but we're not talking about the exact same engines.  There is some extra thrust available, assuming Wikipedia is at least in the ballpark.

 

Edited July 14, 2023 by Rex

[GGTharos]

3 hours ago, Rex said:

I'll admit that my sources are rather lame, but I'm not all that informed on these matters, so I follow the path of least resistance.

Wikipedia shows 31,700lb, but ... yeah ... Wikipedia is probably not an excellent source

That said, it's not like the CFTs are gigantic parachutes.  I mean, I get it, extra weight and surface area, but we're not talking about the exact same engines.  There is some extra thrust available, assuming Wikipedia is at least in the ballpark.

I'm using the -1.  Check my math

The empty weight without CFTs is 33500lbs.

The CFTs add 4400 lbs to this, so you get 37900lbs with CFTs.

The CFTs have a drag index of 20.1 (for reference, two bags or single centerline bag are approximately 11 on the DI, so the CFTs are just shy of the drag index of hauling 3 bags)

The lantirn and tgp add about 1100lbs, with a respective DI of 9.4 and 7.5, for a total of 16.9 and with the CFTs, 37.

Assuming you want to be as clean as possible, your basic DI is 20.1 before we add any air to air weapons, but compared to a light grey you're already configured as if you were hauling three bags and an additional 7000lbs of weight just for existing.

So yes, they're not parachutes, and you've got more thrust but none of this is trivial.

[Hammer1-1]

On 7/11/2023 at 12:50 AM, Theodore42 said:

You must have missed the photo of the new inboard quad pylon.

QUAD DAMAGE!!!!

Those F-15EX guys are going to be playing airquake for real now.

Ive never seen an F-15EX with quad missile racks attached and I work next to the F-15EX assy line. Theres only 5 in existence at the moment, and most of them are on the assembly line.
I will admit I am in the process of finding out what its payload will be specifically, but the only thing I see the F-15EX aircraft loaded up with are dual pylon stations on both wings and an internal weapon bay mounted inside the CFT. Obviously there will be external hard points on them too. Im actually trying to get transferred off the MQ25 program over to the F-15EX line...heres to hoping I get there.

Edited July 15, 2023 by Hammer1-1

[Theodore42]

22 hours ago, Hammer1-1 said:

Ive never seen an F-15EX with quad missile racks attached and I work next to the F-15EX assy line. Theres only 5 in existence at the moment, and most of them are on the assembly line.
I will admit I am in the process of finding out what its payload will be specifically, but the only thing I see the F-15EX aircraft loaded up with are dual pylon stations on both wings and an internal weapon bay mounted inside the CFT. Obviously there will be external hard points on them too. Im actually trying to get transferred off the MQ25 program over to the F-15EX line...heres to hoping I get there.

COOL good luck with that! I was just quoting from that article. In fact I had to double check the authenticity of the article because of the absurdity of the quad-pylon. But there's a picture:

Someone is testing the EX for an air to air mission apparently!

[Hammer1-1]

Im going to find out more about that, but that looks like a mockup. Sure the pylons are real, but most likely inop and for demonstration only. Again Ill find out for sure.

[Theodore42]

2 hours ago, Hammer1-1 said:

Im going to find out more about that, but that looks like a mockup. Sure the pylons are real, but most likely inop and for demonstration only. Again Ill find out for sure.

That would be awesome 

If it's true they really are making the primary mission of the F-15EX air to air then it occurred to me:

IF the strategy is to use lots of airplanes with lots of missiles in BVR and

IF a solution to this you came up with is a quad pylon, 

THEN the platform that would most fit the new equipment (quad-pylon) for the strategy is the F-15E.

Missiles aren't much of a weight restriction relative to any modern fighter but the drag from a quad pylon has got to be insane. BVR means you want to be going fast and high and the faster you're going the more inhibiting drag from the pylons will become. I would imagine the massive power from the F-15EX engines could push through the top-end speed and acceleration limitations of the high-drag quad-pylons better than any other option under consideration.

You want to get real high real fast with lots of drag? I think the F-15E must have looked like the best option for this strategy.

BTW just to clarify, this strategy I'm talking about is just the set of tactics involved in fighting a modern, large scale air to air battle (stealth, AWACS, ECM, ECCM, datalink, etc.). In that environment, a squadron of 12 F-15EX, with radar and equipment that can effectively shoot 192 AMRAAMs within max range and then be able to turn and burn safely away... can you imagine a general saying "no" to that?

[quailman84]

The quad racks are mockups and I think they decided against testing or producing these. The outer wing pylons are usable on current/recent production F-15s allowing an additional 4 missiles as seen on the F-15SA below. 

[Hammer1-1]

I still kind of wonder if those double missile racks on the CFT are going to be included. Those look like they were pulled off an F-18 and wouldnt be too hard to configure into the software. Then again I wonder if they will make use of the racks that are on the upper outboard side of the CFTs for more AMRAAMs. It WILL hold a bunch of AIM120Ds when they come into service and it WILL be a missile truck for stealth aircraft...so many questions. My biggest question is how well it maneuvers. The original F-15EX model was supposed to be a single seater, but they retained the back guy because they plan to implement at some point a UAV wingman like the MQ-28 Australia is buying and they need someone to fly it.