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

[overscan (PaulMM)]

Nice pics Mark, and great to hear about the donation. Will wait for more awesomeness 45 years..... geez, it's older than me... just....

 

[overscan (PaulMM)]

NASA presentation of drag reduction modifications to the F-15 by Bobby Berrier given to Robert Seamans (Sec. of USAF) and Neil Armstrong (Deputy Administrator for Aeronautics)

https://crgis.ndc.nasa.gov/crgis/images/7/79/1971_Berrier_F-15_Presentation.pdf

 

[overscan (PaulMM)]

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.

Hmmm...... I don't think we've seen it yet?

 

[taildragger]

F-15 Satan

See the attached memo for a list of the names proposed for the F-15 in 1971. "Eagle" isn't on the list. While "Demon", "Goblin" and "Ghost" are discounted because of associations with other aviation products, the writer seems unaware that McDonnell had already named a product "Goblin" - the XF-85, one of the ugliest and least successful Fs ever, certainly not something that should inspire a namesake.

 

[overscan (PaulMM)]

Moved some posts from F-15 Projects topic. F-15 Projects topic is for F-15 derivatives post service entry.

 

[Sundog]

The problem with Falcon was they didn't put "Fighting" in front of it.

IIRC, Eagle came from the NAA submission.

 

[Yellow Palace]

I do hope there's some illumination on the acronym base for Fiend. It must have been truly terrible to warrant a mention.

 

[taildragger]

Nope, I don't have any information on the acronym base.

 

[Pioneer]

Can I ask if anyone knows where in the 'McDonnell Douglas Model 199 FX design stage, did the USAF get the notion of the '99-1 kill ratio'??

Regards
Pioneer

 

[overscan (PaulMM)]

Some more NASA photos of the early F-15 with ventral fins.

 

[blackkite]

I can see fences above the engine air intake.

 

[overscan (PaulMM)]

Yes this was seen in some of the artwork previously posted dating to 1970:

 

[blackkite]

Oh thanks a lot my dear owner!!

 

[overscan (PaulMM)]

This was posted on Facebook by the painter himself, Steve Daniels. Done for the USAF before the downselect. Very cool.

 

[GTX]

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: http://postimg.org/gallery/dfl82guc/
Source: http://aviationarchives.blogspot.de/2015/02/f-15-full-scale-mockup-photos.html

I only just noticed - is the following photo showing tandem sidewinders on the front Sparrow hard point?

 

[Mark Nankivil]

They are not Sidewinders - notional representation for the AIM-82 as I recall which was meant for the F-15 program but cancelled.

Enjoy the Day! Mark

 

[GTX]

Ta

 

[Antonio]

AIM-82 - Wikipedia

en.wikipedia.org

 

[molnibalage]

Where came these lots of materials what can't be found anywhere on the Net?
This is one of the best forum topic what I have ever seen.

 

[overscan (PaulMM)]

Mark Nankivil scanned the interesting stuff, mainly, from the Greater St. Louis Air and Space Museum collection and Gerald Balzer's personal collection.

 

[overscan (PaulMM)]

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

As I recall the computer configuration analysis said the diamond delta wing was optimal, and the F-15 wing was refined with good old engineering experience.

 

[apparition13]

What happened to the wing? October '68 it's the contract defintion bid configuration after they spent a year deciding it was the way to go, but by December it's not even in the contract defintion studies.

 

[Mark Nankivil]

What happened to the wing? October '68 it's the contract defintion bid configuration after they spent a year deciding it was the way to go, but by December it's not even in the contract defintion studies.

Not sure what you mean - go back to #14 in this thread and you can see the decision tree that led to the wing as built. That was refined with a different cropped tip during flight test and at the same time, the horizontal stab got a saw tooth to address loading.

Enjoy the Day! Mark

 

[overscan (PaulMM)]

What happened to the wing? October '68 it's the contract defintion bid configuration after they spent a year deciding it was the way to go, but by December it's not even in the contract defintion studies.

Not sure what you mean - go back to #14 in this thread and you can see the decision tree that led to the wing as built. That was refined with a different cropped tip during flight test and at the same time, the horizontal stabe got a saw tooth to address loading.

Enjoy the Day! Mark

Indeed! You can see the starting point was two diamond wings and this was refined to the proposal wing.

 

[AeroFranz]

"tip fold studies"? Was the F-15 anywhere close to exceeding hardened shelter dimensions?

 

[overscan (PaulMM)]

These are the tip fold studies - it was folded in flight for aerodynamic reasons, presumably. Not sure why the nozzle is detached on the second pic though!

 

[AeroFranz]

Intriguing. They are not folding a lot of wing, it's not like it would let you move the aerodynamic center back to a more forward position in supersonic flight (a la XB-70). Similarly, it's not a whole lot of wing area to accomplish much of anything for other purposes either.

IIRC, there were other studies for in-flight wing tip folding, for some reason i'm picturing a Fairchild or Vought project of the same era or slightly earlier vintage. In that case, i think there was a very visible teardrop-shaped fairing that ran chordwise where the hinge was, and the amount of folding span involved was larger.

 

[Sundog]

Intriguing. They are not folding a lot of wing, it's not like it would let you move the aerodynamic center back to a more forward position in supersonic flight (a la XB-70). Similarly, it's not a whole lot of wing area to accomplish much of anything for other purposes either.

IIRC, there were other studies for in-flight wing tip folding, for some reason i'm picturing a Fairchild or Vought project of the same era or slightly earlier vintage. In that case, i think there was a very visible teardrop-shaped fairing that ran chordwise where the hinge was, and the amount of folding span involved was larger.

Yes, you're remembering the Vought V-382 Strike Fighter that was designed to fold the wingtips when in low level flight for higher wing loading, better ride quality.

 

[AeroFranz]

@Sundog Right on, i would have never been able to remember the model!
For the V-382, the penalty of the wing fold would have already been partially absorbed by the need for carrier stowage. It's more puzzling to see a land-based fighter adopt it...

 

[overscan (PaulMM)]

NASA presentation of drag reduction modifications to the F-15 by Bobby Berrier given to Robert Seamans (Sec. of USAF) and Neil Armstrong (Deputy Administrator for Aeronautics)

https://crgis.ndc.nasa.gov/crgis/images/7/79/1971_Berrier_F-15_Presentation.pdf

As the original is no longer available from NASA -

 

[overscan (PaulMM)]

...

 

[overscan (PaulMM)]

...

 

[overscan (PaulMM)]

last...

 

[overscan (PaulMM)]

https://catalog.archives.gov/OpaAPI/media/17419355/content/stillpix/255-grc/255_GRC_1974_00656.jpg

 

[Antonio]

From Aviation Archives Blog

F-15C and F-15 History Article

A copy of the very good article on the F-15 and F-15C aircraft history. Download here or here or here or here (27.6 Megs)

aviationarchives.blogspot.com

 

[elmayerle]

These are the tip fold studies - it was folded in flight for aerodynamic reasons, presumably. Not sure why the nozzle is detached on the second pic though!

Extended nozzle for augmentation, much like the nozzles on the F-111?

 

[sferrin]

Always wondered why the F-111s had the extension (ejector?) but the Tomcats didn't.

 

[elmayerle]

Always wondered why the F-111s had the extension (ejector?) but the Tomcats didn't.

Always wondered why the F-111s had the extension (ejector?) but the Tomcats didn't.

Yes, it's basically an ejector. I suspect weight may have been one problem and reaction time to power changes would be another. If you're cruising, it's one thing, but if you need fast nozzle changes for rapid power changes, a convergent-divergent nozzle works better.

 

[sferrin]

Always wondered why the F-111s had the extension (ejector?) but the Tomcats didn't.

Always wondered why the F-111s had the extension (ejector?) but the Tomcats didn't.

Yes, it's basically an ejector. I suspect weight may have been one problem and reaction time to power changes would be another. If you're cruising, it's one thing, but if you need fast nozzle changes for rapid power changes, a convergent-divergent nozzle works better.

 

[overscan (PaulMM)]

Yes - unlike the photo, the painting doesn't seem to show any attachment between ejector ring and aircraft.