• Hi Guest! Forum rules have been updated. All users please read here.

McDonnell-Douglas Model 199 FX Designs - Evolution of the F-15

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
McDonnell-Douglas VG concepts


[Images removed - better scans below - Admin]
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
McDonnell-Douglas Tailed delta (this was the leading candidate design for sometime, and the final version with rhomboid wings came top in the parametric evaluation; the wing was designed using "designer's intuition" to a more conventional shape).
 

Attachments

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
Nice copy of early F-15 artwork via flateric
 

Attachments

KJ_Lesnick

CLEARANCE: Top Secret
Joined
Feb 13, 2008
Messages
1,021
Reaction score
6
At what point did the F-15 design get the inlets that the F-15 was ultimately fitted with (you know with the inlet lips that can droop down at low speed, and high-AoA's, and droop up for high speed flight...)?

KJ Lesnick
 

Just call me Ray

CLEARANCE: Top Secret
Joined
Aug 26, 2007
Messages
680
Reaction score
0
...probably since the beginning since they were using variable geometry inlets well before that, at least with the F-4.
 

KJ_Lesnick

CLEARANCE: Top Secret
Joined
Feb 13, 2008
Messages
1,021
Reaction score
6
Just Call Me Ray,

I'm just curious because the drawings depicted do not appear to posses it
 

Just call me Ray

CLEARANCE: Top Secret
Joined
Aug 26, 2007
Messages
680
Reaction score
0
Just an assumption, that they just didn't bother to show that level of detail.

Actually the second to last picture seems to have nascent detail of a VG ramp.
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
I'll agree with that - they are artwork and usually dress over the little details such as panel lines, antennas, vents and the like. Those little details usually don't look too pretty in an advertising campaign ;D

My 2 cents worth - Mark
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
4 different intake ramp designs were studied prior to the final FX submission. The selected configuration (4) was the lightest and best performing up to Mach 2.2. Inlet (3) was better above Mach 2.2 but heavier.

So its quite likely that these early designs might have used one of the other inlet designs.
 

KJ_Lesnick

CLEARANCE: Top Secret
Joined
Feb 13, 2008
Messages
1,021
Reaction score
6
Overscan,

If I may ask, do you have any diagrams of the different inlet ramp designs?
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
No drawings. They are verbally described in F-15 PROPULSION SYSTEM DESIGN AND DEVELOPMENT (AIAA 75-1042); the same basic inlet but different ramp arrangements and fixed capture area/variable capture area.

Development Program for the F-15 Inlet (AIAA 74-1061) has detailed information on the actual inlet design and its features and benefits.
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Hi All -

Some artwork from the Greater St. Louis Air & Space Museum archives showing the design evolution of the McDonnell Douglas F-15.

Based on the photo print numbers, this appears to be a decent timeline at what was transpiring.

I have some more to scan from this set but those pretty much fit into the final design layout though you'll see some of the details disappear or morph into what we all know as the Eagle.

Enjoy the Day! Mark



Source:
Greater St. Louis Air & Space Museum Archives via Mark Nankivil
 

Attachments

flateric

CLEARANCE: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
8,781
Reaction score
205
Was dreaming to see 'em in color till got my first Warbirdetch on F-15...and dreams come true. Thanks, Mark!
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
That is very interesting Mark, I will try to reconcile with the timeline I put together before.
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
Also note xD4C 58890 and xD4C 58894 show the same design with wingtips that I guess fold down in high speed flight (judging by the engine intake position) - but what is up with the engine nozzles? They appear to be extended rearwards with a gap in the second picture?
 

Stargazer2006

CLEARANCE: Above Top Secret
Staff member
Senior Member
Joined
Jun 25, 2009
Messages
13,243
Reaction score
85
Wonderful stuff you've been scanning from the McDonnell Douglas archives Mark. It all makes me dream of a coffee-table style book that would feature 200 pages worth of full-page paintings... What a treat it would be!
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Hi All -

A few more McDonnell Douglas bits of art showing the evolution of the FX/F-15. Note on some of the drawings that there is a fence on the upper outboard edge of the intake - I had not noticed that before.

Enjoy the Day! Mark



Source:
Greater St. Louis Air & Space Museum Archives via Mark Nankivil
 

Attachments

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
...and a few more...



Source:
Greater St. Louis Air & Space Museum Archives via Mark Nankivil
 

Attachments

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
Great stuff as usual Mark.

With regard to the dates and numbers, where do these come from? The sequence of numbers and the dates are slightly inconsistent.
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Hi Overscan -

The file names are the numbers stamped (and sometimes dated) on the back of the print. I agree on the inconsistencies but hope to find at some point a master list which we can them use to Id them and see what else they tie to. 'Til then....

HTH! Mark
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
xD4C 70835 Mar-23-70.jpg really looks like an early study - it seems out of place in 1970. The wings and intakes are quite different. Possibly its related to the fence on the intake on the other contemporary pics - clearly struggling with some aerodynamic issue there - perhaps they reconsidered the wing shape and cut back the intakes as alternative?
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Greetings All -

A recent find in the Museum archives was a brochure with artwork of the upcoming F-15 in an earlier form. Note the small fences on the outboard edge of the intakes, the shape of the vertical fin and the ventral fins still part of the design. At some point I'll scan the whole brochure and post a link where you can download it from.

Enjoy the Day! Mark



Source:
Greater St. Louis Air & Space Museum via Mark Nankivil
 

Attachments

flateric

CLEARANCE: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
8,781
Reaction score
205
McDonnell Douglas F-15 litograph (ca.1970)
 

Attachments

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
I have separated out the various FX contenders from other companies from the McDonnell-Douglas FX design, as significant information on the evolution of the McDonnell-Douglas FX design has become available.


Here's some new information on the earliest origins of the F-15 configuration.


Source:
Gerald Balzer Collection via Mark Nankivil.
 

Attachments

Stargazer2006

CLEARANCE: Above Top Secret
Staff member
Senior Member
Joined
Jun 25, 2009
Messages
13,243
Reaction score
85
overscan said:
Interestingly the drawings don't match the VG artwork we have to date:
I can see why the second one picture is different, but what about the first and third? To my (perhaps untrained) eyes they look remarkably similar to the aircraft in the cutaway view... :(
 

overscan

Administrator
Staff member
Joined
Dec 27, 2005
Messages
11,444
Reaction score
765
Side by side - you may be correct. Intake looks different, fixed wing root sweep a bit wrong, but the rest is close. Perhaps the vertical tails are different and a fraction further forward in the artwork too.
 

Attachments

sferrin

CLEARANCE: Above Top Secret
Senior Member
Joined
Jun 3, 2011
Messages
11,942
Reaction score
281
Just at a glance, the intakes are different, as is the leading edge of the swept-back wing. Also, the tail booms extend back further beyond the nozzles in the drawing than in the painting.
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Greetings All -

A visit to Gerry Balzer last week and a review of his folder of F-15 photos and documents uncovered the following drawings of designs and configurations during the development process. Interestingly, the initial starting point according to one of the documents was a variable sweep wing and podded engines. I wonder if that was the case with the loss of the F-14 contract to Grumman and whatever came out of the Model 225 development. Regardless, it wasn't long before the swing wing went away and the fixed wing ruled.

Enjoy the Day! Mark
 

Attachments

Stargazer2006

CLEARANCE: Above Top Secret
Staff member
Senior Member
Joined
Jun 25, 2009
Messages
13,243
Reaction score
85
Cool stuff. So what we had was indeed the Model 199-102. The leading edge was probably straight in the painting because of the angle of view; the extending booms may have been a mistake by the artist.
 

archipeppe

CLEARANCE: Top Secret
Joined
Oct 18, 2007
Messages
1,542
Reaction score
56
overscan said:
Side by side - you may be correct. Intake looks different, fixed wing root sweep a bit wrong, but the rest is close. Perhaps the vertical tails are different and a fraction further forward in the artwork too.
Interesting, it looks like some early western speculation about the Ram K/Su-27 prototypes based upon satellite photos.
 

Mark Nankivil

CLEARANCE: Top Secret
Top Contributor
Senior Member
Joined
Jun 13, 2007
Messages
1,530
Reaction score
142
Greetings All -

I probably should have started off with these first to maintain a time line with the design efforts.

Enjoy the Day! Mark
 

Attachments

Top