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

[Mark Nankivil]

Greetings All -

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

Enjoy the Day! Mark

 

[Mark Nankivil]

As the design gelled, you start seeing the genesis to the eventual F-15. The leading edge flap is interesting - the F-102 wing evolved with the change of its fixed leading edge camber which improved its performance both in cruise and in maneuvering. It looks to me that it was taken one step further by making it variable.

The single engine version (Model 199-104) has a lot of Sukhoi Su-15 looks to it...

Enjoy the Day! Mark

 

[Overkiller]

It's Christmas already???!!!

Amazing drawings, thank you for sharing.

Duncan

 

[Sundog]

The single engine variant impressed me because the power of that engine is similar to that of the F-135 in the F-35. Does anyone know if that was a whole new engine, or if it was based on a previous engine?

Yes, this is like Christmas in May! Thanks guys for all of the great images and info.

 

[overscan (PaulMM)]

Great stuff, I think we have enough info to put together the drawings and artwork into a coherent story.

 

[overscan (PaulMM)]

Note the pop-out Electro-Optical ATAR sensor (later deleted to save money) present on the inboard views.

ATAR (Airborne Tracking Acquisition & Recognition) was a Northrop product, primarily designed for BVR target identification but also for line-of-sight cueing of Sidewinder and replacement short range IR missiles. The USAF flight tested an ATAR system on a McDonnell Douglas F-101 fighter with some success.

This may be it - from Kevin Keaveney's F-101 Minigraph:

 

[overscan (PaulMM)]

Interesting to note that, according to Paul Homsher, F-X deputy general manager, McDonnell were expecting to win VFX and had channelled to bulk of their energy and staff onto the Model 225 for that competition, with only 200 people working on FX. It was only with the loss of that contract to Grumman in Jan 1969 that they quickly ramped up the workforce on F-X to 600 by February and 1000 by March 1969.


Source:


Steve Davies, F-15 Eagle Engaged, Osprey 2007

 

[uk 75]

Gentlemen
I am deeply grateful for the three views of the swing wing versions. I have been after them for many years and it is great to see them here.

 

[mz]

I'm curious: why do the different configurations have vastly different nose sizes? Is it not determined by radar dish size? Or is there a reason to place equipment differently, make a thicker fuselage or place the pilot further back?

 

[Steve Pace]

me thinks you just answered your own question - way to go. -sp

 

[overscan (PaulMM)]

NASA drawings and photos of DR-10X windtunnel model. Probably belongs more to TFX program but clear ancestor of the early FX VG design and shown earlier in topic from FX report (models on left):



Sources:


A SUMMARY OF RESEARCH ON VARIABLE-SWEEP FIGHTER AIRPLANES
https://web.archive.org/web/2010052...casi.ntrs.nasa.gov/19720066119_1972066119.pdf


NASA TM X-832
https://web.archive.org/web/2010052...casi.ntrs.nasa.gov/19720065315_1972065315.pdf

 

[overscan (PaulMM)]

DR-10X model also shown as "McDonnell TFX-1" from 1961.


http://www.secretprojects.co.uk/forum/index.php/topic,526.msg131222.html#msg131222

 

[overscan (PaulMM)]

NASA model of the pre-tail-surgery F-15, which shows very well the vertical fences on the intakes.

 

[Mark Nankivil]

Really nice finds for all of these threads - thanks! Mark

 

[sferrin]

Where did you get that pic. and are there anymore in that series?

 

[Stargazer]

I have reworked the Model 199-VS100C plans into one single file (see attachment).

I noticed an obvious mistake in the original document: the Model 199 is actually called "99", very likely a typo from the person who assembled the various elements (a close look reveal that the titles are a patchwork of separate elements that must have been cut out and glued in the old-fashioned way... the initial "1" could easily have been missed out in the process). I therefore corrected the mistake in the image below. I also elected to turn the top view 90° for aesthetic purposes.

 

[overscan (PaulMM)]

Thats really nice work Stephane, thanks for sharing it.

 

[flateric]

coool! thank you!

 

[Mark Nankivil]

Well done Stephane, thanks! Mark

 

[overscan (PaulMM)]

Been working on the F-15 Evolution topic, matching up drawings, paintings, and dates. Piecing together the different evolution timelines into the overall picture. WIP.

 

[hesham]

Excellent work my dear Paul.

 

[overscan (PaulMM)]

Revised the timeline:

 

[hesham]

Revised the timeline:

That's better my dear Paul.

 

[overscan (PaulMM)]

Unfortunately I haven't been able to find any drawing of the designs immediately preceeding the submission which is now the only hole in my timeline with vague silhouettes only.

 

[foiling]

I love your time-line chart, Paul. It is fascinating & rich in information. Well done.

 

[Delta Force]

When/why did the F-15 lose 2D thrust vectoring during its development?

It's also interesting how similar some of these designs are to the F-14, at least in terms of appearance. One of the variable geometry designs has thrust vectoring too, that likely would have been a very maneuverable design.

 

[fightingirish]

F-15 Speed Brake Development
One of the three main visual differences between pre-production and production aircraft is the length of their speed brakes. Short for pre-production and long for production. Jack Abercrombie (Former McAir Chief Aerodynamicist) has written a great article on the history of the F-15 speed brake development.

BTW: The other two are the clipped wing tips (covered below) and the notched horizontals.

Pictures: https://postimg.cc/gallery/b2LCKRD
Source: http://aviationarchives.blogspot.de/2014/12/f-15-speed-brake-development.html

AGARD F-15 Performance
0001 If you are interested in F-15 aerodynamic performance, then Jack Abercrombie wrote a paper for the Advisory Group for Aerospace Research & Development (AGARD) in October of 1977 that you will like. While technical, it has good information for the lay person. Have a look!

File: http://aviationarchives.net/AGARD F-15 Performance.pdf
Source: http://aviationarchives.blogspot.de/2014/12/agard-f-15-performance.html

Forty Years of F-15 Air Supremacy
In 2012, Jack Abercrombie wrote several articles and a slide show to commemorate the 40th anniversary of the F-15’s first flight. They detail the challenges of bringing along a new aircraft and the changes that were required to the airframe to enable it to be the world class fighter that it became.

This is a must read for anyone who is interested in the F-15 Eagle and it’s history from the man that was there!

Files:

• Click here to download the slide show in PDF form
  
• Click here to download the slide show text in PDF form
  
• Click here to download the beginnings in PDF form

Source: http://aviationarchives.blogspot.de/2014/12/forty-years-of-f-15-air-supremacy.html

 

[fightingirish]

F-15 Vertical Tail Revisions & ‘70 Tail Configuration

Jack Abercrombie sent along an interesting comparison chart of F-15 tail development size and placement plus a little known tail configuration from 1970.

His note said:
“Here are a few pages from MCAIR Report A0270, 30 Jan 1970 describing the new configuration (at the time) with the nacelle fences for directional stability improvement. Note that the configuration includes the middle size vertical tails (55 square ft each--larger than those of the 1969 proposal which were 41.4 each) and almost the original Ventrals (21.4 sq ft vs 20 sq ft per). The fences helped through improvements to the sidewash characteristics, but not enough. It was more than a year later (Apr '71) when the ventrals were removed and still larger verticals (the current 62.6 sq ft per) were incorporated.”

Large size pictures: https://postimg.cc/gallery/CZMDfnV

Source: http://aviationarchives.blogspot.de/2015/01/f-15-vertical-tail-revisions-70-tail.html

 

[overscan (PaulMM)]

Oops. Accidentally merged the two F-15 topics. Should be split out again now. That 1970 drawing is useful to add to my timeline.

 

[Triton]

McDonnell Douglas F-15 concept lithograph found on eBay.

Source:

http://www.ebay.com/itm/VINTAGE-F-15-EAGLE-MCDONNELL-DOUGLAS-LITHOGRAPH-17x11-/191500206425?pt=LH_DefaultDomain_0&hash=item2c964d4159

 

[Triton]

This profile view doesn't look like the configuration that was manufactured.

 

[fightingirish]

F-15 Full Scale Mockup Photos
Several photos of the original full scale F-15 model that was on display in the Bldg 002 “Blue Room”.

Pictures: https://postimg.cc/gallery/ZdHW4mq
Source: http://aviationarchives.blogspot.de/2015/02/f-15-full-scale-mockup-photos.html

 

[fightingirish]

F-15 Early Configuration Lithographs
I have shown some of these lithos before; but, I thought that it would be nice to put them all together. These illustrate the early F-15 configuration with the short verticals and the ventral fins.

Pictures: http://postimg.cc/gallery/vwshvrgk/
Source: http://aviationarchives.blogspot.de/2015/02/f-15-early-configuration-lithographs.html

 

[fightingirish]

F-15 Early Configuration Lithographs
I have shown some of these lithos before; but, I thought that it would be nice to put them all together. These illustrate the early F-15 configuration with the short verticals and the ventral fins.

Pictures: http://postimg.org/gallery/vwshvrgk/
Source: http://aviationarchives.blogspot.de/2015/02/f-15-early-configuration-lithographs.html

Please notice the details on these lithographs, like the 2nd one with the air fences on the intakes. ???

 

[sienar]

Described as an early F-15

More here, including 2d nozzle stuff: http://crgis.ndc.nasa.gov/historic/1146_Posters_and_Displays

 

[overscan (PaulMM)]

Not early, no - has cutoff wingtips and dogtooth on tail.

 

[archipeppe]

Described as an early F-15

More here, including 2d nozzle stuff: http://crgis.ndc.nasa.gov/historic/1146_Posters_and_Displays

This is a blueprint for a Wind Tunnel test model.

 

[overscan (PaulMM)]

Added in a few stray posts.

 

[RAP]

Original painting of early MD F-15

$10K, a little out of my range.

http://www.ebay.com/itm/1969-Historic-McDonnell-Douglas-First-Full-Color-Illustration-of-F-15-Eagle-/322551427377?hash=item4b19903131:g:yW8AAOSwx6pYqEdK

 

[Mark Nankivil]

Greetings All -

We recently received a treasure trove of goodies in a donation from a retired McAir engineer - some great F-15 design material that I'll post when I get the chance to scan them.

In the meantime, and in recognition of the upcoming 45th Anniversary (!!!) of the 1st flight, here's two images of a wind tunnel model of the early configuration with short upper vertical fins and ventral fins, both which changed substantially with the final design produced.

Enjoy the Day! Mark