McDonnell-Douglas / Boeing F-15 Eagle

[sferrin]

I hope that, unlike the Super Bug, they won't have to drop the million dollar IRST if they have to clean up for ACM.

I too have found that decision rather questionable. If not a housing incorporated into the airframe like F-35 EOTS, wouldn't just adopting something like the Sniper XR advanced targeting pod make more sense?

It seems to be about par for the course with the "Super" Hornet. Goes quite well with all of it's air brakes, er. . .pylons.

 

[Lampshade111]

Does the canting on the pylons have that much of an effect? If so wouldn't the Navy or Boeing done something by now?

Personally I think the FA-18E and FA-18F are fine aircraft if you take them for what they are. A medium sized, multi-purpose, "low cost" design. Yet despite the AESA radar and everything they pack into it, it is not a true air-superiority aircraft, or a long range strike aircraft. I would be prefer it if the Navy had a larger NATF type design or even the Super Tomcat. The Super Hornet should have been a replacement for the standard Hornet, not the backbone of naval aviation.

 

[F-14D]

I hope that, unlike the Super Bug, they won't have to drop the million dollar IRST if they have to clean up for ACM.

The IRST centerline tank on the Super Hornet is not jettisonable (except I assume in an emergency jettison.) Keeping one relatively small tank going into ACM isn't going to be a major problem for a plane that big.

My understanding it that the IRST is going into modified standard Super Bug centerline tanks, and those are jettisonable if the need arises (close in ACM). Fuel capacity of the tanks is reduced 25-30%. Now, you may not want to jettison the tank, given what you'll lose, but I find it hard to believe the Navy deliberately would saddle our crews with such a restriction. Of course, this begs the question: I thought the -18E/F was supposed to have all kinds of internal room for growth. It's about the same size as the -14, and this was one of the selling points. Why couldn't the IRST be mounted like on the Tomcat?

 

[Lampshade111]

Could vibrations from firing the M61A2 cause problems? This was a concern with the radar back when the original Hornet was in development.

 

[F-14D]

Does the canting on the pylons have that much of an effect? If so wouldn't the Navy or Boeing done something by now?

Personally I think the FA-18E and FA-18F are fine aircraft if you take them for what they are. A medium sized, multi-purpose, "low cost" design. Yet despite the AESA radar and everything they pack into it, it is not a true air-superiority aircraft, or a long range strike aircraft. I would be prefer it if the Navy had a larger NATF type design or even the Super Tomcat. The Super Hornet should have been a replacement for the standard Hornet, not the backbone of naval aviation.

If you're talking about the outward cant, I believe it has two effects. Drag goes up a bit, and range goes down a bit. Also, this reduces the so called "Frontal stealth" claimed for the Super Bug (which actually only applies if it's clean.

I think the cant came about because of a semantic game that occurred early when the E/F was being sold to the world.. The wording was that the E/F had two more stations to carry weapons. This was true. there were two more stations to carry weapons. However, the inner pylons when pointed straight ahead as originally designed, did not meet the requirements for safe clearance from the fuselage. So, although you could indeed carry powered weapons on the inner pylons, you couldn't fire them from those pylons as originally designed. They would have been restricted to fuel tanks or unpowered weapons. The solution was to cant the inner, and consequently all other to avoid conflicts, pylons outward a bit in order to meet safe clearance requirements.

Or so I understand.

Remember, if there had been an NATF, A/FX, Super Tomcat 21 or even continued production and upgrade of the F-14D, there would be no need for the F/A-18E/F.

 

[F-14D]

Could vibrations from firing the M61A2 cause problems? This was a concern with the radar back when the original Hornet was in development.

Don't forget, there was an M61 in the nose of the Tomcat

 

[Lampshade111]

Oh, I hadn't seen a F-14 up-close in so long, I kinda figured it was located on the shoulder. Need to dig up one of my reference books and refresh myself on the F-14.

Regarding the need for the FA-18E/F, If the NATF had entered service and the A-12 had still been canceled, there would still have been the need for an attack aircraft with greater range and payload than the Hornet. I don't believe a ground attack capability was ever planned for the NATF, correct? Even if we had gone with the Super Tomcat 21 I imagine a relatively low cost replacement for the Hornet would be wanted sooner or later. Hornet 2000/Super Hornet could have provided that.

When the A-X become A/F-X was the intent to replace the regular Hornet among the A-6, etc? If the Navy had gotten a flood of cash and permission to do what they wanted, would they have perused a separate F-14 replacement after or along with the A/F-X, or one of the proposed upgrades for the F-14?

 

[Abraham Gubler]

Of course, this begs the question: I thought the -18E/F was supposed to have all kinds of internal room for growth. It's about the same size as the -14, and this was one of the selling points. Why couldn't the IRST be mounted like on the Tomcat?

Money. There is the volume for IRST inside the E/F but it costs a lot less to integrate ISRT into a fuel tank than it would to integrate it into the aircraft and then have the aircraft's changed aerodynamics be recertified.

As to jettisoning the IRST you are only going to do this when it comes down to do anything to stay alive. The E/F can do some pretty wild stuff with external stores. The standard air show routine configuration for E/Fs these days is four big draggy, underwing pylons and 2,000 lbs of stores (AMRAAM, LGB or JDAM capture carry dummies).

 

[F-14D]

Of course, this begs the question: I thought the -18E/F was supposed to have all kinds of internal room for growth. It's about the same size as the -14, and this was one of the selling points. Why couldn't the IRST be mounted like on the Tomcat?

Money. There is the volume for IRST inside the E/F but it costs a lot less to integrate ISRT into a fuel tank than it would to integrate it into the aircraft and then have the aircraft's changed aerodynamics be recertified.

As to jettisoning the IRST you are only going to do this when it comes down to do anything to stay alive. The E/F can do some pretty wild stuff with external stores. The standard air show routine configuration for E/Fs these days is four big draggy, underwing pylons and 2,000 lbs of stores (AMRAAM, LGB or JDAM capture carry dummies).

That's a credible rationale, although I note that (with the possible exception of the F-15, unless it is built into the pylon) everybody else seems to be able to put it internal. Also, the Hornet has always been a "blessed" program in that Congress always has made available just about whatever money was asked for. The F-35 is the first competing program that has ever put a damper on that. My point in my previous post was that one of the many rationales strongly pushed for the E/F was that it was supposed to have all this internal room relative to the C/D to add new systems, yet now that one of those systems has arrived, it's being mounted externally in a less benign environment.


On the F-15, does anyone know yet if it's be an external store or built into a pylon, as was proposed for the FLIR on the A-7F (the story of which I'll get to someday)?

 

[Sundog]

On the F-15, does anyone know yet if it's be an external store or built into a pylon, as was proposed for the FLIR on the A-7F (the story of which I'll get to someday)?

From the article I posted the link to at the top;

Unlike the F/A-18's IRST pod, which is mounted at the front of a fuel tank, the F-15 version will feature a sleeker pod design mounted on its "Station 5" stores pylon, says Brad Jones, Boeing's F-15 radar modernisation programme manager. A similar pod has already been supplied for South Korea's F-15K fleet.

Although mounted on the aircraft's belly, the long-range sensor will have the ability to look up by 5°, Jones says. As a passive sensor, the IRST pod will augment the F-15C/D fleet's mechanically and electronically scanned radars to search for enemy aircraft and missiles at very long range, he adds.

Apparently they don't expect their opponents to fly at higher altitudes than they do. I can't help thinking this has more to do with cruise missile defense than it actually does A2A combat. Either that or it's range capabilities are so great, 5 degrees is all you need to see what's above you at a distance. Which should give some warning, but it sure won't be tracking. Does this mean PAK-FA won't be operating near F-22 territory?

 

[F-14D]

On the F-15, does anyone know yet if it's be an external store or built into a pylon, as was proposed for the FLIR on the A-7F (the story of which I'll get to someday)?

From the article I posted the link to at the top;

Unlike the F/A-18's IRST pod, which is mounted at the front of a fuel tank, the F-15 version will feature a sleeker pod design mounted on its "Station 5" stores pylon, says Brad Jones, Boeing's F-15 radar modernisation programme manager. A similar pod has already been supplied for South Korea's F-15K fleet.

Although mounted on the aircraft's belly, the long-range sensor will have the ability to look up by 5°, Jones says. As a passive sensor, the IRST pod will augment the F-15C/D fleet's mechanically and electronically scanned radars to search for enemy aircraft and missiles at very long range, he adds.

Apparently they don't expect their opponents to fly at higher altitudes than they do. I can't help thinking this has more to do with cruise missile defense than it actually does A2A combat. Either that or it's range capabilities are so great, 5 degrees is all you need to see what's above you at a distance. Which should give some warning, but it sure won't be tracking. Does this mean PAK-FA won't be operating near F-22 territory?

With an IRST it's always a tradeoff where it goes. Except in the very nose, some of its view is going to be blocked by the fuselage. Sometimes this is addressed by how the a/c postions itself. On the F-14D, the IRST could track, "...at Phoenix ranges". It's also worthy of note that a variant of this sensor is used on the YAL-1 airborne laser.

 

[Abraham Gubler]

Apparently they don't expect their opponents to fly at higher altitudes than they do. I can't help thinking this has more to do with cruise missile defense than it actually does A2A combat. Either that or it's range capabilities are so great, 5 degrees is all you need to see what's above you at a distance. Which should give some warning, but it sure won't be tracking. Does this mean PAK-FA won't be operating near F-22 territory?

Well this isn't quite true. The look up angle of an under fuselage or underwing ISRT is more than enough to enable tactical detection of much higher flying aircraft.

As to pod vs internal the funding for the Super Hornet 'Flight Path' (or is it Flight Plan? Always forget) of upgrades is a US Navy initiative without much Congressional interest and is of course competing with lots of other stuff. Saving a few million or tens of millions with the pod solution was needed to enable it to go ahead (discussion with the Project Manager).

 

[red admiral]

I was having a look at the F-15 recently and found something that rather puzzles me. Hopefully someone with more experience of the aircraft can help with some explanation.

From the Standard Aircraft Characteristic, the Flight Design Gross Weight is listed as 37400lb at which 9g is the service g load. Above this weight, the service g load should reduce (37400*9/weight). So, at about 50,000lb, the service g load should be 6.7g

The chart below shows the Overload Warning System limits which are a function of Mach and Weight. From what I've been able to discern, this gives the pilot an audio tone that he is about to exceed the service g load. However, if we use the chart, say for Mach 0.85/sea level/50,000lb this gives 8.25g as the g load achievable before the warning system starts to tone. This doesn't agree with the above, as you're able to overstress the airframe by 23% before the warning kicks in.

Can anyone shed some light on this please?

Thanks very much

 

[lastdingo]

9 G is probably the pilot limit, while the airframe could probably do more.

There may also be a negligible effect due to bending wings.

 

[kcran567]

The f-15 can pull up to 14 g's, and a few pilots have done that in combat without damaging the airplane, but then again I know of one F-15 that ripped its nose off at the fuselage connection probably due to metal fatigue from continued over stressing.

 

[rousseau]

require the 14g source

 

[aim9xray]

A few thoughts to consider:

1: The chart that was posted is for a symmetric (non-rolling, non-yawing) maneuver.

2: The lower limit seen for the "rule-of-thumb" calculation may have sufficient margin to allow for asymmetrical maneuvers which cause different load patterns and concentrations in the airframe than the symmetric load. External stores also reduce the allowable margin.

3: The concern with an "over-G" is not just with damage for the primary airframe structure (i.e. wings "breaking off")- secondary elements such as landing gear uplocks, door hinges and engine mounts are particularly critical.

One of the YF-105As lost a main landing gear (uplock failed, the gear extended and was ripped off by airloads) while in a windup turn. The airframe was written off after a subsequent belly landing on the Edwards lakebed that broke it's back.

For a long time, the early Navy F-4Bs had a 6.5 G (symmetric) limit due to engine mounts. (The mounts themselves could not be strengthened alone; that would have just reacted the loads deeper into the primary structure which have been much more difficult and expensive to repair.)

 

[saintkatanalegacy]

require the 14g source

he prolly meant the guy in history channel who wasn't fazed during a "14 g maneuver" :

 

[Dreamfighter]

Bit off topic perhaps, but have Japanese and Israeli F-15's the same G-limit as USAF's F-15's? (C-version)
The same aircraft can have different G-limits with regard to the country it is operated by and requirements imposed by it's airforce. For example:
US' F/A-18C/D's have a 7.5 G-limit, while the Finnish' or Swiss' F-18C's (don't remember by heart if it are the Finnish or the Swiss, I'd have to look it up) have a 9 G-limit - with relatively minor reinforcements to the airframe. Their F-18's (not designated F/A-18's) are purely intended for A2A-combat and therefore have a higher manoeuver-requirement.

 

[lastdingo]

The F-15E was strengthened for low level flight and may have a different max. G load than C/D for this reason.

 

[red admiral]

Thanks very much for the replies. You've given me some ideas to look into.

 

[Mark Nankivil]

The initial Israeli Eagles were very early A models and in a couple of cases, reworked FSD Eagles so it may be possible they had different G limits for those airframes. As for the Eagle that lost its nose/cockpit section, that was a 131st FW Missouri Air National Guard aircraft from where I live (St. Louis). It was determined that a number of aircraft were built with longerons through the cockpit section (along the canopy rails) that were of a smaller cross section then were spec'd which led to fatigue cracking that in turn led to the loss of this aircraft. The fleet grounding found a few more with the same problem and in the case of one other with the squadron here, never flew again except for a one way trip to the boneyard.

The inflight break up is detailed here: http://www.youtube.com/watch?v=U22_7jsQy7s

Enjoy the Day! Mark

 

[datafuser]

A July 1982 document "THE REAGAN DEFENSE BUDGET: FAILING TO MEET THE THREAT" at http://www.policyarchive.org/handle/10207/9028 quoted then USAF chief as shown below in page 25.

"According to General Charles A. Gabriel, new Air Force Chief-of-Staff, NATO air superiority is possible only if "we can use standoff tactics and engage them [the Soviets] beyond visual range, outnumbered seven to one. We would lose that edge if visual identification is required before each shot" 33 Unfortunately, this condition is unlikely to obtain because NATO aircraft lack an effective identification-friend-or-foe device (IFF) that pinpoints enemy aircraft beyond visual range."

33 Quoted in "Burgeoning Warsaw Pact Threat Spurs Dual Challenge ," Aviation Week and Space Technology, June 2, 1982, p. 44.

In the 1991 Gulf War, USAF F-15Cs could engage the Iraqis beyond visual range, relying on electronic ID. Exactly when did this electronic ID capability become operationally available to the USAF F-15C force?

 

[overscan (PaulMM)]

I think you should consider that the second part "Unfortunately, this condition is unlikely to obtain because NATO aircraft lack an effective identification-friend-or-foe device (IFF) that pinpoints enemy aircraft beyond visual range" is written by the author of this piece, not a quote from the Air Force Chief-of-Staff.

F-15s had the AN-ALQ-128 EWWS, a newer version of "Combat Tree", the hostile-IFF-exploiting detection device which was very successful in Vietnam and the Iran-Iraq war, which would allow beyond-visual-range identification. USSR was at that time in the throes of replacing the compromised Kremniy IFF system with Parol, which may or may not have had an effect on the usefulness of this. I believe this is still a classified system.

The AN/ALR-56 RWR can classify hostile radar emitters by type, which would also allow BVR engagements in some situations.

Finally, NCTR software for the AN/APG-63 radar came with MSIP (from 1985) with progressive improvements.

However, if you read the first hand accounts of the Gulf War, you will realise none of these systems were infallible, and in lots of engagements the F-15 pilots ended up with VID.


The Gulf War F-15s were MSIP II standard without AMRAAM, I believe.

 

[datafuser]

I think you should consider that the second part "Unfortunately, this condition is unlikely to obtain because NATO aircraft lack an effective identification-friend-or-foe device (IFF) that pinpoints enemy aircraft beyond visual range" is written by the author of this piece, not a quote from the Air Force Chief-of-Staff.

F-15s had the AN-ALQ-128 EWWS, a newer version of "Combat Tree", the hostile-IFF-exploiting detection device which was very successful in Vietnam and the Iran-Iraq war, which would allow beyond-visual-range identification. USSR was at that time in the throes of replacing the compromised Kremniy IFF system with Parol, which may or may not have had an effect on the usefulness of this. I believe this is still a classified system.

The AN/ALR-56 RWR can classify hostile radar emitters by type, which would also allow BVR engagements in some situations.

Finally, NCTR software for the AN/APG-63 radar came with MSIP (from 1985) with progressive improvements.

However, if you read the first hand accounts of the Gulf War, you will realise none of these systems were infallible, and in lots of engagements the F-15 pilots ended up with VID.


The Gulf War F-15s were MSIP II standard without AMRAAM, I believe.

Thanks for the explanation, Much appreciated.

Other 1980's documents assessed there would be a lot of blue-on-blues if BVR shots without VID was allowed in a Central European scenario.

What was the official doctrine on BVR shooting in the 1980's? Did the doctrine say it was OK to shoot BVR without VID?

 

[flateric]

was it ever published in open sources? can anyone help with that?

 

[GTX]

Any ideas re this latest Israeli F-15 mod - specifically the hump behind the cockpit?

 

[lastdingo]

DIRCM, SatCom - dunno.
Just had the urge to reply. B)

 

[flateric]

from a friendly forum via roberto_yeager - ELTA ELK-1891 SATCOM
http://forum.keypublishing.com/showpost.php?p=1951705&postcount=4


http://www.youtube.com/watch?v=GM3V0HHsgY8

 

[overscan (PaulMM)]

Looks like R2D2 to me

 

[GTX]

ok. Satcom was my initial thought, though the radome did look a little large. Never-the-less.


Now, I wonder why Israeli F-15s might require long range Satcom... ;D

 

[CliffyB]

Looks like R2D2 to me

You mean like this?

Sorry, couldn't resist ;D

Now, I wonder why Israeli F-15s might require long range Satcom... ;D

We'll probably learn why soon enough... Hope we're all still here afterwards.

 

[Orionblamblam]

Looks like R2D2 to me

Hmm. The F-15s as X-Wings, the Israelies as the Rebel Alliance, surrounded by a much bigger and more powerful evil empire... you know, it works!

 

[Archibald]

ahmadinejad as Palpatin ? poor Palpatine then... he must depressed by his role... (what, I'm that ugly and evil ? going into rehab and platic surgery immediately)

 

[chuck4]

Indonesian Su-30 MKI has similar looking lumps, probably supplied by SAAB.

 

[bob225]

hi all, following crash of USAF F-15 from Lakenheath last year:


http://m.bbc.co.uk/news/uk-england-suffolk-31867486


http://www.usafe.af.mil/shared/media/document/AFD-150312-012.pdf


Hopefully of interest

 

[jsport]

Never a more timely requirement.

Hoping FA-XX is large enough. believe material science supports a decently maneuverable craft with a rather large payload.

 

[Sundog]

According to the book "F-15 Eagle Engaged" by Steve Davies and Doug Dildy, it states on page 19 regarding the September 1968 RFP requirements for the F-X that the fighter was among other things to be capable of achieving "Global (intercontinental) ferry range with or without aerial refuelling"

The exact passage reads as follows (It's a caption on the right side of the page)

F-X Design Requirements

The September 1968 RFP required the F-X design submissions to
provide a fighter with:


1. Wing optimized for high load factor (g) and buffet-free
performance at Mach 0.9 at 30,000ft altitude;
2. High thrust-to-weight ratio to achieve very high energy
maneuverability throughout the flight envelope;
3. Mach 2.5 maximum speed at altitude;
4. Long-range pulse-Doppler radar with look-down capability;
5. One man operation of the weapons system for all missions;
6. Advanced cockpit layout, displays, and controls, which would
allow heads-up operation during close-in combat;
7. Airframe fatigue spectrum with a life of 4,000 hours;
8. 360 degree cockpit visibility;
9. High maintainability: 11.3 maintenance man hours per flight hour
(similar to WW2 fighter requirements);
10. Significant increase in avionic and airframe subsystem component
mean time between failure (MBTF);
11. Highly survivable structure, fuel, hydraulic, flight control and
electrical subsystems in a combat environment;
12. Self-contained engine starting without need for groupd support
equipment;
13. Global (intercontinental) ferry range with or without aerial
refuelling;
14. Maximum air superiority mission gross weight in the
40,000lb class;
15. Low development risk components (engine and radar) and
airframe subsystems which had been proven in prototype,
pre-production, or production applications.



Source: Steven, James Perry McDonnell Douglas F-15 Eagle, Aero
Publishers, Fallbrook, CA, 1978.

Bold Emphasis Mine


How long, distance-wise, would an airplane need to be able to fly for the US Military to consider it intercontinental or global? Could anybody venture a guess as to whether this range would be with drop-tanks or on just internal fuel?

Was the plane able to actually meet this specification?


KJ Lesnick

The range would be with drop tanks. Trying to do so on internal fuel alone would greatly drive up the size, hence weight and cost.

 

[Flyaway]

Hope the pilot is found alive.

Pilot found dead after US fighter jet crashes into North Sea off Yorkshire coast

A major search-and-rescue operation was launched after the F-15 fighter jet came down near Flamborough Head on Monday morning.

news.sky.com

 

[FighterJock]

The wreckage has been found they are still looking for the pilot, the plane was on a training mission according to the BBC.

https://www.bbc.co.uk/news/uk-england-suffolk-53051055