FX Competition (F-15 alternatives)

hesham

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in this competition, the main contenders were:-

1-Boeing model -----?
2-Northamerican-Rockwell NR-349
3-Vought V-483.
4-lockheed CL- -----?
5-Grumman G-300.
6-General Dynamics model -----?
7-Fairchild-Hiller (Republic division) model ----?
8-McDonnell-Douglas F-15 model ----?
can anyone identify the unknown contenders ?.
 

hesham

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I am sorry,and I will correct my fault.
 

overscan (PaulMM)

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FX Studies

April 1965 - FX studies begin. Air Force Systems Command studies end up recommending a 60,000lb VG design with air-air and air-ground capability.

December 1965 - RFP issued to 13 companies for concept formulation for a TSA (Tactical Support Aircraft)

March 1966 - 8 bids recieved. All were VG designs except Northrop. Boeing, North American Rockwell, Lockheed awarded contracts. Vought (V-483), McDonnell-Douglas (Model 199), Grumman (G-300?), Northrop make unsuccessful bids. McDonnell-Douglas carries on in-house studies on Model 199 from April to December 1966 without funding, as does Grumman. Rockwell work on a primary VG design and a second, higher risk blended fixed wing design, which seems to promise to make VG unnecessary. A closely related fixed wing design (NR-323) was submitted to the VFX competition, despite having little chance of succeeding, perhaps to gain experience for the FX program.

Air Force were unimpressed with all three designs from chosen contractors.

USAF runs its own Concept Formulation Study from Autumn 1966 to Autumn 1968. John Boyd contributes a series of tradeoff studies and in early 1967 arrives at the 40,000lb, manouvreable "Blue Bird" concept.

August 1967 - RFP for a Fighter, Experimental (FX) concept formulation sent to 7 contractors. Thanks to John Boyd, a more manouverable 40,000lb plane was envisaged. McDonnell-Douglas and General Dynamics issued contracts. North American, Lockheed, Fairchild-Hiller and Grumman all participated using company funds. Grumman's FX studies included Model G-399.

Ran through to May 1968.

General Dynamics recommended both fixed and variable geometry designs, while McDonnell-Douglas recommended fixed wing, two engines, single crew.

May 1968 – concept definition agreed. RFP for FX contract definition issued to McDonnell-Douglas, North American, Grumman, General Dynamics, Lockheed, LTV, Fairchild-Hiller, Boeing.

August 1968 – Only 4 serious bids were received; North American (NR-335), McDonnell-Douglas (Model 199B), Fairchild-Hiller and General Dynamics. General Dynamics was eliminated, and contracts were awarded to the remaining three. F-15 designation was reserved for FX winner. Rockwell's wing design had more than 8,000 hours of wind tunnel testing behind it.

October 1968 – participants asked to consider Navy adaptability.

From July to December 1969 ASD (Aeronautical Systems Division) evaluated the three proposals. McDonnell-Douglas was announced the winner December 23, 1969.
 

hesham

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Thank you dear Overscan very much,please help us in A-6 Competitors.
 

overscan (PaulMM)

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I have some good illustrations of Fairchild, Grumman and General Dynamics FX designs to post tonight and an additional one of the Rockwell design.
 

Pioneer

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Bring them on 'Overscan'!

Regards
Pioneer
 

overscan (PaulMM)

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Sources:

Tony Buttler, 'Steps to the Big League' Air Enthusiast (highly recommended)
Joshua Stoff, The Thunder Factory Arms & Armour Press, 1990
James Perry Stevenson, McDonnell-Douglas F-15 Eagle Aero Publishers 1978
Jeff Ethell, Modern Combat Aircraft 12: F-15 Eagle Ian Allan 1981
Mark A. Lorell & Hugh P. Levaux, The Cutting Edge - A Half Century of U.S. Fighter Aircraft R&D Rand 1998
Michael J Gething, Modern Fighting Aircraft 1: F-15 Eagle Salamander 1983
Dennis R. Jenkins Warbirdtech 09: F-15 Eagle Speciality Press 1997
Dennis R. Jenkins F-15 Eagle Aerofax 1998
Unknown Internet sources
 

Sundog

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Hey Overscan,
Have you ever seen a 3-View drawing of that VG GD submission? That looks awesome!
 

elmayerle

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overscan said:
Grumman Model 399

Hmm, now that one looks like a F-15 cockpit blended with a F-14 would make a good start. If the inlets are 2-D inlets (like the F-14's) and under the LERX, it likely would have superb high-AOA performance.
 

overscan (PaulMM)

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Sundog said:
Hey Overscan,
Have you ever seen a 3-View drawing of that VG GD submission? That looks awesome!

I downloaded the picture from the net - I had photocopied it from Air International in black and white and then discovered it online in colour. I don't have any more information.
 

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Those designs are really impressive "could have been". Has anyone 3-view drawings, especially of the NAA - Rockwell proposal?. The available drawing is of very poor quality.
Thanks in advance.
 

overscan (PaulMM)

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Small snippet of info.

Northrop declined to bid for FX because they didn't believe they had a chance of winning a major non-export order, so they teamed with Rockwell on their bid. If Rockwell had won, Northrop would have been the major subcontractor.
 

Archibald

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You like whatif ? try this one !
http://www.whatifmodelers.com/forum/index.php?s=16a62e67a2dc71a2766ebffcc72f3506&
;D
 

Deino

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hesham said:
in this competition, the main contenders were:-

...
5-Grumman G-300.
...

Does anyone have a picture or drawing of that Grumman study ... later on "only" model-399 is depicted ??

Thanks in advance, Deino :)
 

KJ_Lesnick

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Was that picture of the GD F-X design the final proposal or just one of them? Why did they go with swing-wings -- carrier landings weren't essential?

KJ
 

flateric

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KJ_Lesnick said:
Why did they go with swing-wings -- carrier landings weren't essential?

KJ

Why does Tornado use VG wings? Why does Su-24 and MiG-23/27? Going and reading http://en.wikipedia.org/wiki/Swing-wing
No more off-topic here.
 

KJ_Lesnick

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I'm confused about the 40,000 lb weight requirement, was that maximum takeoff weight? Or was that combat weight?

From what I remember the F-15A weighed 44,000 lbs at combat weight and 56,000 at maximum takeoff.


Kendra Lesnick
 

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I'm kind of curious as to what happened, and when during the FX program. I've heard some information which is kind of conflicting and I'm not exactly sure which one is correct, and some information which just has me confused.

This part I'm pretty sure about
-The FX program starts as a replacement to the F-4 Phantom, multi-role capability, some of the designs have swing-wings (although I'm not sure which), with a max weight of 60,000 lbs. (I'm not sure if the design was to be a twin-seater at this early stage or not)

Pretty sure about this part too...
-USAF/Major Boyd/Pentagon/ after seeing the F-4's less than stellar record in Vietnam realize it's not a good design and the FX would essentially be a replacement to a design they don't want.

Confused about this part
-Major Boyd comes up with a specification for a twin-engined, (I think multi-role) 40,000 lb fighter (when in air-to-air config) with a 1.4 to 1 T/W Ratio, and light wing-loading, to be powered by low-bypass, afterburning turbofan engines.
-Major Boyd comes up with a specification for a single-engined, (I think multi-role) 25,000 lb fighter (when in air-to-air config) design, to be powered by low-bypass, afterburning turbofan engines, inspired by the MiG-21 which had caused a great deal of trouble in Vietnam
-Major Boyd comes up with a specification for a twin-engined, (I think multi-role) 40,000 lb fighter (when in air-to-air config) with a 1.4 to 1 T/W Ratio, and light wing-loading, to be powered by low-bypass, afterburning turbofan engines, then for one reason or another (Perhaps fearing the FX will become another F-4) draws up specifications for a fighter (which I assume is multi-role) with a 25,000 lb single-engined fighter (when in air-to-air config) design, inspired by the MiG-21 which had caused a great-deal of trouble in Vietnam


Confused Here as well
-MiG-25 ends up being mistaken for a superfighter, scares the USAF sh*tless, and the FX-design is revised to meet the MiG-25's performance (at least in terms of speed; Maj. Boyd draws up initial specifications for a 40,000 pound (I'd assume multi-role) fighter (assuming the 25,000 pound single-engine design was the first design cooked up) with a 1.4 to 1 T/W ratio, light-wing loading and MiG-25 top-speed. Airplane to be powered by two 0.6:1 bypass turbofan engines.
-MiG-25 ends up being mistaken for a superfighter, scares the USAF sh*tless, and the FX design is revised to meet the MiG-25's performance (at least in terms of speed); Maj. Boyd centers back on the 2 engined, 40,000 lb (gross-weight/air-to-air weight) design with the 1.4 to 1 T/W ratio and the light wing-loading, but with the MiG-25's top-speed, and the bypass-ratio reduced to 0.6:1 (I remember hearing something about initial specifications being quite broad in regards to the bypass ratio, as high as 1.5 to 1 allowed, but to meet the MiG-25's performance, 0.6 was selected to be the best)
-MiG-25 ends up being mistaken for a superfighter, scares the USAF sh*tless, and the FX design is revised to meet the MiG-25's performance (at least in regards to speed); Maj. Boyd adds the MiG-25 maximum speed requirement to the 40,000 lb fighter twinjet design, and specifies an optimum turbofan bypass-ratio of 0.6 to 1.

Another source of confusion
I saw at least some F-15 drawings which depicted a swing-wing derivative type design. I know the early FX designs were very large and many had swing-wings, but eventually the weights and T/W requirements changed, and the design seemed to change to a fixed-wing design. However, what's confusing is I saw a diagram which showed many studies McD was persuing and it showed looking at swing-wing designs just before selecting the final designs, and personally (out of confusion and lack of information) wonder if the swing-wing was briefly picked up when the MiG-25 max speed was added to the equation to make it easier to reach that speed, then then went back to a fixed wing when they found out they could do the job on a fixed wing.

I'm certainly not trying to "sponge". It's just I've seen various information online, even books about the F-15, and I've got conflicting data in some areas which I listed. I'm wondering which is correct, which is not.


Kendra Lesnick
 

GTX

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Your parts about John Boyd aren't quite accurate. If you want the story in this great man's own words have a look here:



It was his development of the Energy Maneuverability Theory (amongst other things) that was more relevant in the analysis of the FX proposals

Regards,

Greg
 
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overscan (PaulMM)

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r16

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alas , GTX's doesn't show on my web computers . Would you mind giving a direct link ?

as a personal note , the "Mafia" has regressed considerably in these years .Actually I had a small pdf where a present day member had the temerity to question the P-47's value as a fighter .
 

GTX

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Not sure what happened there. Try searching on "Col John Boyd, USAF (Ret), briefs at AU in the twilight of his life." in Youtube and you'll fine a series of videos with John Boyd presenting. I think it is the first where he discusses the F-15 story.

Regards,

Greg
 

KJ_Lesnick

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Boyd strikes me as being a guy who is highly intelligent, but rather hyperactive.
 

GTX

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He was quite a character - read a bit about him: there are a few books around now.

Regards,

Greg
 

overscan (PaulMM)

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Note that this patent, having some similarity to the General Dynamics VG FX configuration, is mentioned as being a continuation in part of an abandoned 1971 patent application, so despite being from 1976, could be of interest.

http://www.google.com/patents?id=jZE7AAAAEBAJ&pg=PA2&dq=3,942,746&source=gbs_selected_pages&cad=1_1#PPA1,M1
 

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How are those rocker ramp exhausts supposed to function with afterburning?
 

Mark Nankivil

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Greetings All -

I scanned this image from the Greater St. Louis Aviation Museum collection at the same time as the artwork. It appears to be a test run of a exhaust deflector similar to what is shown in the first two artworks at the top of the page - the delta shaped wing and brown/green camo. Looks like a crude (compared to today's 2D & 3D nozzles) to deflect the exhaust plume for added pitch control. Comments?

I can see it now - the crew chief calling the pilot and telling him it's time to land - the steaks are ready to throw on the deflector "grill" ;D

Enjoy the Day! Mark
 

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overscan (PaulMM)

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The designs shown in Mark's artwork is the so-called "twin-throat" exhaust, this was studied extensively during the F-15 program. It offered the promise of substantial reductions in interference drag over conventional nozzles. A double wedge was mounted horizontally across the exhaust duct, thereby providing "twin-throats" for each nozzle. It was also adaptable to thrust vectoring control and reversal, although this was not an F-15 requirement. Wind tunnel tests suggested the drag reduction was real, but penalties in weight, possible difficulties with cooling, and above all technical risk, stopped further consideration.

More info in

Richard E. Martens F-15 NOZZLE/AFTERBODY INTEGRATION (AIAA 74-1100)
http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=45882
 

overscan (PaulMM)

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So working from this topic and American Secret Projects we have many, many FX designs identified.

The following are still mysteries:

Boeing : FX studies made, no designation known
Lockheed: CL-979 (early) and CL-1000 (later)
Vought: V-483
Northrop: FX studies made, no designation known

Anyone got anything? Yes, I know, I'm never satisfied :)
 

overscan (PaulMM)

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overscan said:
So working from this topic and American Secret Projects we have many, many FX designs identified.

The following are still mysteries:

Boeing : FX studies made, no designation known
Lockheed: CL-979 (early) and CL-1000 (later)
Vought: V-483
Northrop: FX studies made, no designation known

Answering my own question - it seems Northrop didn't study VFX or FX that seriously; they had agreed to be major subcontractors to North American Aviation in the event of a win in either competition.
 

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Does anyone know how, or why, the name Eagle was chosen for the McDonnell Douglas F-15? Were there other names suggested for the aircraft?
 

F-14D

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Triton said:
Does anyone know how, or why, the name Eagle was chosen for the McDonnell Douglas F-15?
<snip>

PR. no doubt
 
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