McDonnell-Douglas Model 199 FX - design and development of the F-15

[overscan (PaulMM)]

McDonnell-Douglas VG concepts


[Images removed - better scans below - Admin]

 

[overscan (PaulMM)]

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).

 

[overscan (PaulMM)]

Winning design.

A 2D "rocker ramp" exhaust which allowed thrust reversal (the central paddle split to form a V shape) was considered.

 

[overscan (PaulMM)]

Nice copy of early F-15 artwork via flateric

 

[overscan (PaulMM)]

McDonnell-Douglas FX studies and early F-15.


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

 

[KJ_Lesnick]

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]

...probably since the beginning since they were using variable geometry inlets well before that, at least with the F-4.

 

[KJ_Lesnick]

Just Call Me Ray,

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

 

[Just call me Ray]

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]

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 (PaulMM)]

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]

Overscan,

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

 

[overscan (PaulMM)]

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]

Hi All -

A couple of pages out of the McAir Report "Design, Integration and Testing of the F-15" dated Sept. 1974
from the Greater St. Louis Aviation Museum Archives.

Enjoy the Day! Mark



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

 

[Mark Nankivil]

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

 

[Mark Nankivil]

...and a few more...



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

 

[Matej]

Very nice! Thank you Mark.

 

[flateric]

Was dreaming to see 'em in color till got my first Warbirdetch on F-15...and dreams come true. Thanks, Mark!

 

[overscan (PaulMM)]

That is very interesting Mark, I will try to reconcile with the timeline I put together before.

 

[overscan (PaulMM)]

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?

 

[Stargazer]

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]

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

 

[Mark Nankivil]

...and a few more...



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

 

[overscan (PaulMM)]

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]

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 (PaulMM)]

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]

Greetings All -

I found a few more prints in the Greater St. Louis Air & Space Museum archives of early F-15 display models.

Enjoy the Day! Mark


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

 

[Mark Nankivil]

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

 

[flateric]

McDonnell Douglas F-15 litograph (ca.1970)

 

[overscan (PaulMM)]

McDonnell Model 199 was assigned 7th May 1965 as LA/ASF - Light Attack - Air Superiority Fighter. Described as "low altitude attack, respectable air-to-air capability".


Source: McDonnell Design List
http://www.secretprojects.co.uk/ebooks/McDonnell%20Model%20Numbers%20List.pdf

 

[overscan (PaulMM)]

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.

 

[overscan (PaulMM)]

Here is the podded engine VG configuration 199-100-1 and fuselage engine VG configuration 199-102-1. These are from a report dated 31 May 1968.



Source:
Gerald Balzer Collection via Mark Nankivil.

 

[overscan (PaulMM)]

Some of the F-4 Phantom II (Model 98) variants listed in the drawing above...

 

[overscan (PaulMM)]

NASA images of the original F-15 design with ventral fins.


http://crgis.ndc.nasa.gov/historic/1251_Models_M-P#McDonnell

 

[Stargazer]

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 (PaulMM)]

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.

 

[sferrin]

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]

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

 

[Stargazer]

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]

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.