F-15 Silent Eagle

[Desert Dawn]

It must be noted that all USAF and Army aircrafts (including old types) are already coated with radar absorbant paint.

I didn't know that all AF and army aircrafts have radar absorbant paints ??? Where did you get this info?

Directly from the pilots, many years ago.
It`s no big secret actually. There was an article in the local press about 10 years ago about a bunch of surplus Canadian army jeeps that were sold to the public after being demilitarized. Those were the real Jeep models (a model a bit later than the original from WWII). The guy who bought one of them is an history buff and wanted to keep if in its original camouflage and army configuration. He was clearly told that the jeep in question was painted with radar absorbant paint (yes, even ground vehicles). So, it`s not just in the US apparently.

 

[Lampshade111]

I can't help but think that the ability to carry an internal weapons load is rather unneeded on this aircraft. While this modification will certainly keep the Eagle a 1st rate combat aircraft I can't imagine this being much stealthier than the Super Hornet. Since four AAMs would also be rather limited, I imagine it will usually fly with external stores anyway.

Now they just need LOAN nozzles with optional thrust vectoring if a customer has enough money. This would certainly win over many countries considering buying Flanker variants.

 

[TomS]

There's a common tendency to confuse radar and infrared, especially among people who don't know but want to sound clever (a group that includes an amazing number of military personnel in non-technical jobs). IR reflective paints are very common in ground vehicles to help match their signatures to the background in near-IR imagers (nost NVGs, for example). Radar absorbent paints in ground vehicles are exceedingly rare.

In aircraft, it's known that Tornados flying in Desert Storm (for example) received some LO coatings and tiles that had been held as war reserve modifications (Flight International 16-22 October 1991.) It seems reasonable that such modifications might be common on aircraft almost 20 years later.

 

[lantinian]

The latest episode of the Check 6 podcast has a discussion about the unveiling of the F-15 Silent Eagle and its implication on the market. Listen to the first 10 min.
http://www.gcast.com/user/Check6/podcast/main?nr=1&&s=230226978

 

[ouroboros]

I can see why they are reusing development work from the CFT's, but it makes me wonder why they didn't pursue a ventral conformal pack between the engines, sorta like this Flanker concept. Either in addition to or as an alternative to the left/right CFT's.

 

[lantinian]

I can see why they are reusing development work from the CFT's, but it makes me wonder why they didn't pursue a ventral conformal pack between the engines, sorta like this Flanker concept.

You only need to have a look at the bottom of the F-15 and SU-27 to figure that out.
1. There is no space to fill like on the flanker as the engines of the F-15 are next to one another
2. Unlike the Flanker which has at least 2 hard-points between the engines, the F-15 has only one.
3. The main F-15 undercarriage does not allow for anything wider than a fuel tank to be attached there.

 

[AeroFranz]

Pardon my ignorance, but where did that stealthified Su-27 come from? was that an official project or just some guy photoshopping a picture?
The inlets rotated through 90 degrees are kinda interesting.

 

[flateric]

some guy = Paralay
www.paralay.com

Last hints say that intakes were left 'as is' on planned EWF version of Flanker, and space between nacelles was filled with aerodinamically shaped 'bulb' with forward vertical wedge, with provisions for third MLG 'leg' in the center to compencate increasing TOW. Supersonic speed went down, but subsonic went up as it was in case of fast packs on F-15.
It was studied by one of Sukhoi's top gurus Vladimir Antonov more than 25 years ago.

http://forums.airbase.ru/2009/03/t66575--F-15-Silent-Eagle-s-elementami-Stealth.html

 

[AeroFranz]

I had no idea there had been such an effort at Sukhoi.

It was studied by one of Sukhoi's top gurus Vladimir Antonov more than 25 years ago.

Has this modification been promoted more recently, or has it quietly died down?

 

[flateric]

it lives and not only in the case of -27, reportedly we will see something quite soon

 

[LowObservable]

EWF??????

 

[flateric]

EW/ECM and ESM

 

[avatar]

Yup the silent eagle reminded me of the "exotic" sukhoi effort in the nineties as well.


AFAIR Sukhoi came up with a souped up Su-35 configuration to impress UAE . didn't work. they opted for block 60 instead.

 

[fightingirish]

F-15 Silent Eagle: The Movie
posted by Stephen Trimble at Flight International Blog - The Dewline on June 11, 2009 5:29 PM
[flash=200,200]http://www.youtube.com/watch?v=9xoRT1_9Jgo[/flash]

 

[flateric]

Graham Warwick was the first, in fact, to post this video http://www.youtube.com/user/theworacle

 

[Orionblamblam]

Some stills from the new video:

More at my blog, http://up-ship.com/blog/?p=2836

 

[Demon Lord Razgriz]

Those nozzles look like they're TVC!

 

[Scorpion82]

I don't think they are TVC, because if the engines would feature TVC they would proudly claim it.

 

[Thorvic]

According to Flight, news from Paris is that Boeing are not going to fund a prototype of the SE at this time.

Probably holding out to see if they get any overseas enquiries first and then encourage them to part fund the development.

G

 

[flateric]

Boeing F-15 Silent Eagle Demonstrator Makes 1st Flight

ST. LOUIS, July 9, 2010 -- The Boeing Company [NYSE: BA] Silent Eagle flight demonstrator aircraft F-15E1 completed a successful first flight on July 8 from Lambert St. Louis International Airport. During the 80-minute flight, F-15E1 opened and closed its left-side Conformal Weapons Bay, which contained an AIM-120 Instrumented Test Vehicle (ITV) missile. The ITV was not launched.
"The Silent Eagle demonstration flight validated our initial engineering design approach," said Boeing F-15 Development Programs Director Brad Jones. "Our intent was to verify all systems are operational in a flight environment. This flawless flight allows us to move into the next phase. In the next couple of weeks, we will ferry F-15E1 to the test range and launch an AIM-120."
"Everything about the flight went according to plan," said Boeing F-15 Chief Test Pilot Dan Draeger. "We saw nothing unusual during the flight, and we cleared the desired flight envelope needed to fire the missile at the test range; that is pretty much unheard of on a first flight."
The Silent Eagle is an innovative design solution developed in response to international customer requirements for a cost-effective, high-performance fighter aircraft to defend against future threats. The F-15SE offers unique aerodynamic, avionic and Radar Cross Section reduction features that provide the user with maximum flexibility to dominate the ever-changing advanced threat environment. The aircraft's Conformal Weapons Bays can carry a variety of air-to-air missiles and air-to-ground weapons.
# # #

Photo (c) Boeing

 

[lantinian]

Finally!

Congratulation to Boing. I wish we have seen more upgrade solutions like that. The gap between the US 4 gen and 5 Gen fighters is still too wide.

Can't wait for pictures from the front. It will probably look strange to people used to seeing Eagles with strait tails for 35 years. Their first reaction might be that here is something wrong. :

 

[SOC]

Can't wait for pictures from the front. It will probably look strange to people used to seeing Eagles with strait tails for 35 years. Their first reaction might be that here is something wrong. :

That one is just an old F-15E demonstrator outfitted with the new CFTs containing weapons bays. It still has straight tails, and probably lacks a lot of the other intended improvements.

 

[flateric]

Photo (c) Boeing

 

[sublight]

I can hardly wait for the inevitable silent eagle vs. F35 price/performance ratio comparison....

 

[sferrin]

I can hardly wait for the inevitable silent eagle vs. F35 price/performance ratio comparison....

I'm looking forward to when dawns on some that for the F-15SE to actually get anywhere meaningful they're going to have to hang external tanks on it (destroying much of what they saved in the RCS dept.) because the CFTs no longer hold fuel but AAMs and their launch mechanisms. ;D

 

[Trident]

I can hardly wait for the inevitable silent eagle vs. F35 price/performance ratio comparison....

I'm looking forward to when dawns on some that for the F-15SE to actually get anywhere meaningful they're going to have to hang external tanks on it (destroying much of what they saved in the RCS dept.) because the CFTs no longer hold fuel but AAMs and their launch mechanisms. ;D

A very relevant comment. The SE CFTs do retain a certain amount of fuel tankage IIRC, but compared to a non-CFT F-15 armed with 4 lower drag conformal AMRAAMs the Silent Eagle might turn out to be a LO upgrade first and foremost. Not that there's anything wrong with that, but it is a point to consider.

 

[sferrin]

The problem in the F-15's case is that it's got relatively little internal fuel. Even less than the Super Hornet (and it has much more powerful engines drinking the lower amount of internal fuel). That's one of the reasons the Eagle got CFTs so early. They were talking about them even before the original Strike Eagle demonstrator in the early 80s came along.

 

[Abraham Gubler]

I'm looking forward to when dawns on some that for the F-15SE to actually get anywhere meaningful they're going to have to hang external tanks on it (destroying much of what they saved in the RCS dept.) because the CFTs no longer hold fuel but AAMs and their launch mechanisms. ;D

I don’t know where you got this conclusion from. The CFTs are effectively drag neutral in subsonic flight for an F-15. So an F-15SE will have the same mission radius for cruise and loiter flying as an F-15C, which isn’t exactly known as a short legged bird. That’s >1,000 NM combat radius with ~14,000 lbs of internal fuel (no CFTs).

The problem in the F-15's case is that it's got relatively little internal fuel. Even less than the Super Hornet (and it has much more powerful engines drinking the lower amount of internal fuel). That's one of the reasons the Eagle got CFTs so early. They were talking about them even before the original Strike Eagle demonstrator in the early 80s came along.

LOL.

 

[quellish]

"The Mach 2.5 speed of the Strike Eagle is maintained, but the cost is about 180-200 nautical miles of range capability because of the reduce fuel in the conformal tanks, says Brad Jones, program manger for F-15 future programs."

source: http://www.aviationweek.com/aw/generic/story.jsp?id=news/Silent031709.xml&headline=Boeing%20Unveils%20New%20Stealthy%20F-15&channel=defense

 

[lantinian]

"The Mach 2.5 speed of the Strike Eagle is maintained, but the cost is about 180-200 nautical miles of range capability because of the reduce fuel in the conformal tanks, says Brad Jones, program manger for F-15 future programs."

source: http://www.aviationweek.com/aw/generic/story.jsp?id=news/Silent031709.xml&headline=Boeing%20Unveils%20New%20Stealthy%20F-15&channel=defense

Now that's interesting. I am not an Eagle expert but I do believe the F-15 could only reach Mach 2.5 with 4 sparrows attached conformally and no CFTs
Not sure if the F-15E with CFTs can carry 4 AMRAAMs up to Mach 2.5 (probably not)

The most interesting thing of course will be the ability to carry a JDAM or a SDB that fast. Not sure even if the Raptor can do that, let alone launch ithem. I think the F-22 weapon bay door did have a operational speed limit but I think that was well belloW Mach 2.

So it will be interesting to see if this upgrade will give the Eagle a multirole supersonic weapons capability for longer standoff ranges in addition to lower signature and increased range.

 

[Abraham Gubler]

Now that's interesting. I am not an Eagle expert but I do believe the F-15 could only reach Mach 2.5 with 4 sparrows attached conformally and no CFTs.

The CFTs were designed and tested for full envelope flight. Obviously they changed the drag profile but compared to pylon stores were up to 3 times less additional drag. Drag from the CFTs actually decreased as the faster you went over Mach 1.2.

Not sure if the F-15E with CFTs can carry 4 AMRAAMs up to Mach 2.5 (probably not)

Again it should be able to carry them and launch them but it’s going to be a lot draggier (so more thrust needed) than an F-15C with conformal carriage of AIM-120.

The most interesting thing of course will be the ability to carry a JDAM or a SDB that fast. Not sure even if the Raptor can do that, let alone launch ithem. I think the F-22 weapon bay door did have a operational speed limit but I think that was well belloW Mach 2.

You can carry them but AFAIK weapons release for Mk 80 series bombs is only tested up to Mach 1.3. You need a different bomb design if you want it to fly in a predictable way at high Mach speeds.

So it will be interesting to see if this upgrade will give the Eagle a multirole supersonic weapons capability for longer standoff ranges in addition to lower signature and increased range.

Weapon’s launch won’t change a thing but tactically significant stealth will.

 

[donnage99]

Now that's interesting. I am not an Eagle expert but I do believe the F-15 could only reach Mach 2.5 with 4 sparrows attached conformally and no CFTs
Not sure if the F-15E with CFTs can carry 4 AMRAAMs up to Mach 2.5 (probably not)

The most interesting thing of course will be the ability to carry a JDAM or a SDB that fast. Not sure even if the Raptor can do that, let alone launch ithem. I think the F-22 weapon bay door did have a operational speed limit but I think that was well belloW Mach 2.

"....researchers from Boeing Phantom Works and the Air Force Research Laboratory used a rocket sled and active flow control to successfully release a MK-82 Joint Direct Attack Munition Standard Test Vehicle at a speed of about Mach 2 (twice the speed of sound) from a weapons bay with a size approximating that of the U.S. Air Force B-1 bomber."
http://www.boeing.com/news/releases/2007/q4/071126a_nr.html
I'm o areodynamic expert, so I don't know if it's possible to implement active flow control to the f-15SE weapon bays' system.

 

[lantinian]

Weapon’s launch won’t change a thing but tactically significant stealth will.

I appreciate your comments about the CFT but I highly disagree here.

The USAF makes a big thing out of the fact that the F-22 can launch wepaond from supersonic speeds and increased altitude allowed by the lower signature.

These new Hybrid CFT are the lowest dead designs so far as they lack external pilons. Further, a Silent Eagle will typicaly not carry even the main underwing pilot as well.

My main point is that the new configuration potentilly reduces drag as a side effect as compared to any previously used operational configuration enabeling pilots for the first time to fly an armed F-15 troughout it's flight envelope.

That to me is a significant tactical capability. Not to mention that you have ground weapons in the mix and as with the Raptor, weapons mix is irrelevant to the flight profile. You can for instance fly supersonicaly with asimetrical bomb load if it is internal.

An F-15C with 8 AAMs on board is limited to Mach 1.7 Any drop Fuel tank will make it a subsonic fighter.

 

[Abraham Gubler]

My main point is that the new configuration potentilly reduces drag as a side effect as compared to any previously used operational configuration enabeling pilots for the first time to fly an armed F-15 troughout it's flight envelope.

Nope. The F-15 did have an interception configuration that was just four Sparrows. This is no longer a likely and important mission configuration because the requirement for high speed interception of large formations of MiG-25s and Tu-22Ms went the same way as the dinosaur, black and white TV and the Soviet Union.

Now there is no reason why a ‘Loud Eagle’ F-15 can’t fly in a low drag configuration with maybe one or two bombs, no CFTs/AAMs, no external tanks, etc for a radar targeted, supersonically dropped, long range bomb strike using JDAM for a “first day” type strike mission. Similar to the F-22 JDAM/SDB capability but not low observable. Sure the internal carriage of a weapon of two in the CFT is going to have lower subsonic drag but the difference in transonic/supersonic drag is not going to be significant. The increase in drag of the CFTs goes from 0 sqf at Mach 0.9 to 2 sqf at Mach 1.0 to 4 sqf at Mach 1.2 and then down to 3 at Mach 2.0. A brace of Mk 84s will be about the same, except adding about 2 sqf at subsonic speeds.

 

[lantinian]

Exept that 2 MK-84 is not at all what that these new hybrid bays are all about.

Their typical payload will be aditional fuel (~1 drop tank), 2xAMRAMS and 4xGBU-39s (or 2xMK-83 based JDAMs)

 

[Abraham Gubler]

Their typical payload will be aditional fuel (~1 drop tank), 2xAMRAMS and 4xGBU-39s (or 2xMK-83 based JDAMs)

Well that changes everything (throws hands in the air)...

(sarcasm alert over)

The whole point is that internal carriage of weapons in CFTs - which BTW is nothing new, McAir were talking about this back when they were called "Fast Packs" and "fuel pallets" - would 'transform' the F-15's capability because of supersonic low drag weapons carriage. Currently the F-15A, B, C, D and E can fly without the CFTs and with pylons with only a reasonable increase in drag as long as you stay away from super draggy 600 gallon fuel tanks. The CFT became the bees knees for the F-15 because it actually reduced drag in subsonic flight (compared to a clean F-15) and enabled you to carry another ~1,500 gallons of fuel with much less transonic/supersonic drag than two or three 600 gallon tanks. But it doesn't provide a great drag advantage other low drag conformal or particular low drag pylon loads.

 

[RanulfC]

Ok dumb question but is the SE an F-15 UPGRADE program or something for foreign sales?

Randy

 

[Mark Nankivil]

My understanding is both. If you have airframes to convert, they'd be interested but buying new will get their full attention

Enjoy the Day! Mark

 

[lantinian]

Yes, actually interal carriage of the same weapons does provide a significant operational advatanges:
1. You do not have to worry about different drag profiles and how will that influence actual range.
2. You have more diverse weapons loadouts which you don't have to fligh certify. Ex 1xAIM-9X, 1xAMRAAM, 1xJDAM, 2xSBDs.
3. Because flight profile is not changed you can afford to have asymetric loads. Don't have to drop both bombs at the same time. You can still fly supersonic with one bomb left, and you don't have to use flight controls to compensate and create induced drag.

4. You don't have to worry about how the external payload influnences signature
5. You can carry loads that are not optimised for supersonic flight, supersonicaly efficiently.

I am really starting to get amazed at how you try your best to not see the merrits of this engineering solution beyond the official statements.

Also saying that this has been atempted before is completely ingnoring the facts. Research done on internal wepons launchers has only started to produce a really good solutions in the last decade.
Some weapons like the AIM-9 and Guided Bombs were extremely space consuming until thier latest incarnation.

The F-15SE does use some much of what has already been paid for as part of the F-22 and JSF programs. As such it is low cost but highly effective upgrade. And because of the large installed base of compatible aircraft, it has a huge sales potential( if only congress approves it).

The only thing I want to know right now is the max speed/maneuvering condition for releasing an AMRAAM from the top rail launcher.

 

[Abraham Gubler]

Yes, actually interal carriage of the same weapons does provide a significant operational advatanges:

I guess we have very different measures of the word significant (important, notable, or momentous). The Super Hornet came with a flight calculator providing the pilot with constantly updated endurance figures for variable profiles on remaining fuel, current drag, altitude, etc and I don’t hear anyone raving about how significant it is to the nature of contemporary air combat.