Northrop / McDonnell Douglas ATF - YF-23 and EMD F-23

[Matej]

Image removed - modified drawing in the next posts.

 

[flateric]

Fantastic stuff, Mato! Thanks zillion, zillion times!!!
I have some add-ons, but will wait with them.

 

[ChuckAnderson]

Hi Matej!

Like flateric, I like the F-23 and I wish it had entered production. I've always thought that the F-23's situation could be analogous to that of the F-16/F-17 situation.

As we know, in the competition between the F-16 and the F-17, the F-16 won the contract and the F-17 was pushed into the background until it was picked-up by the USN as the F-18.

Like the F-17 that was picked-up later as the F-18, it's too bad that the F-23 couldn't be picked-up later as the.....F-23.


Chuck

 

[Matej]

Well, small chance as F/B-23 still lives.

 

[Archibald]

Hmmm.. don't want to start a stupid, Key-publishing like boring discussion, but wouldn't the F-23 been a better choice for the USN than the Superbug ?
thanks for the 3-view, very interesting...

 

[flateric]

Folks, please stop talks about why YF-23 lost, what a great AF fighter it would be and what a great Navy fighter it could be - I'm pretty sceptic about later estimate.

Remarks to Mato -
a). In a plan view, all intake edge lines are straight, no these curved outer lips.
b). F-23A would have the same nozzles with top covergent/divergent flaps, as YF-, just trenches' tiles would be changed in favor of more light, flexible insulation pattern, and configuration of serrated boattail in planview would be changed to improve weight, IR and stealth characteristics (later shown right).

 

[Ogami musashi]

I still try to figurate the new shape of the engines fairings.

Did they were make come closer to each other?
How their size was reduced? including in height?

It seems from Matej and koku fan drawing that the aft part of the fuselage on the upperwing was lenghtened, right?

 

[elmayerle]

These inlets appear to be a blend of aerodynamics from the prototype and some of the work that eventually showed in in the X-35 and F-35 inlets.

As for why the YF-23 lost the competition, the outbrief after the decision was pretty clear that Northrop's then management had lost the trust and confidence of USAF leadership (IMHO, it was a desevered loss).

 

[flateric]

Adding to El opinion about loosing the competition - Bill Sweetman describes system of choosing of competitors as taking two radically different designs (i.e. YF-16/YF-17, YF-22/YF-23, X-35/X-32) even if counterpart wasn't scored second in preliminary, 'paper' RFP stage contest (for example, Boeing LWF was scored second to GD's, but USAF choose Northrop's two-engined design as contender to GD LWF as this a/c was a totally different approach on how LWF should look like). You can note striking similarites between Boeing and Northrop ATF designs (except, of course, this weird fuselage mouth inlet).

 

[flateric]

I still try to figurate the new shape of the engines fairings.

Did they were make come closer to each other?
How their size was reduced? including in height?

It seems from Matej and koku fan drawing that the aft part of the fuselage on the upperwing was lenghtened, right?

You can easily compare both variants overlaying each other in any CAD program (as sizes are known). In common, you are right.

 

[Matej]

Fixed - intake configuration suggestions

 

[Antonio]

In my opinion this is one of the most beautiful fighter aircraft ever designed :

Thanks for the drawing Matej!

 

[Matej]

Not an impartial person but....

"I worked at Pratt & Whitney Aircraft during the development period of the ATF prototypes in R&D on the ATF engine program so I really paid close attention to the ATF flyoff when it happened.
The engines selected was Pratt & Whitney F-119-PWA-100 NOT the GE-120. GE was nearly three months late getting their prototype dual cycle engine working. In fact the GE prototype powered flight item was supposed to be the first to fly but due to GE's problems the PWA prortotype powered item flew first. The GE engine delivered more thrust BUT was far more thirsty and had a much larger thermal footprint. The PWA protype only needed a slight fan Dia. increase to make up the thrust difference. The GE needed far more work to be a viable production engine and had a higher cost. Winner of ATF engine contract PWA!"

John former Dept 7035 Fabrication specialites PWA Rocky Hill, Ct. Facility 1987-1992

 

[Matej]

Only eight days and you can legaly build your own copy of YF-23

 

[rousseau]

two questions for Matej:
1) Why use zigzag wing on backside
You should have known the dentate wing edge would destroy a capability of low detection from radar

2) Why use 3 dimentions shockwave half cone airintake?
The cone specially for this half cone airintake will cause an unsymmetrical air flow while the aircraft do any high attacking angle of maneuver.

 

[flateric]

Ca. 1991 Koku-Fan has published 3-view of EMD F-23A, Matej drawings based on this illustration. Dimensions (lenght, for example) and overall shape was pretty different from then already released YF-23 drawings and overall dimensions. Text capture mentioned that there were drawings, showing, among other details, additional internal bay for AIM-9s, occasionally distributed (and immidiately returned back) to the press representatives during YF-23 roll-out ceremony, fact, confirmed at least by one other independent source (Flight International, AFAIK). Other insider source also confirmed that these drawings are very close to CAD printouts of EMD F-23 that he has seen, including 'B-2 style' inlets with serrated cowls. Dogtooth at the leading edge is strange to mee too, I never seen such an aerodynamic/stealth arrangement. I can suppose that vortices produced by them can interference with -23 giant V-tails to improve stability at high AOA, that was a problem of this ATF competitor, but it's just speculated guess.

 

[Matej]

1. I think (like the flateric) that the tooth was placed there because it can create an additional vortices. And regarding to stealth, it is the matter of the shape, materials and size, not if something is zigzag or not.

2. This type of cone is simply much easier and less expensive than original porous used on YF-23 prototype. People in Northrop found that its not necessary to always remove boundary layer from the inlet and the cone can be integral part of the fuselage without gap between. This is exactly what is now applied on F-35.

 

[elmayerle]

Well, as was demonstrated on the JIST testbed, there are other ways to remove the boundary layer than using splitter plates. This has been incorporated on the X-35 and now the F-35 and I assume Northrop would use the same approach on any FB-23 proposal. I've heard that the final F-23 proposal dropped the sawtooth inlets as unncessary, but I couldn't verify this.

 

[Sundog]

2. This type of cone is simply much easier and less expensive than original porous used on YF-23 prototype. People in Northrop found that its not necessary to always remove boundary layer from the inlet and the cone can be integral part of the fuselage without gap between. This is exactly what is now applied on F-35.

Actually, that's a mis-interpretation. It is important to remove or 'move' the boundary layer before the inlet, there are just different ways to do it. The bump before/in the inlet serves to cause the pressure distribution in front of the inlet to push the boundary layer around it. At least that is what has been reported in some of my aviation magazines. Also, they probably use porous materials in the inlet to suck the boundary layer away, as was done on the YF-23 prototypes inlet; That's the dark "patch" you see under the wing in front of the inlet on the YF-23.

 

[Matej]

Some alternative weapon configurations made from my drawing by Nikolay Andreev. I just forgot to remove the scale - image is sized down to be able to post it here.

 

[elmayerle]

In all the comparative flight test data I saw (and I was at Northrop at the time), the YF-23 consistently outperformed the YF-22, could carry as much, and the production proposal had a more flexible, in terms of carriage, internal weapons bay set up with the builkhead between the two bays capable of shifting fore and aft like the bulkhead between weapons bays 1 & 2 on the B-1B. Where the F-23 proposal fell down, majorly, was on the management side; the USAF not having tremendous faith at that point in Northrop's ability to manage the program. This is the information that was conveyed to the engineers after the post-award de-brief by the USAF.

Oh, the extensive sawtooth shown isn't necessary (take a look at the F-35's inlet, or that flown on the JIST testbed to prove out the theory behind it. The YF-23 didn't need vectoring nozzles, it already was as maneuverable as the YF-22 and the nozzles just add complexity and weight.

Matej, if you want to add an alternate reconnaisance capability that was palletized, consider a shape similar to the lower front of TSSAM, both front and back, faired into the surface contours, and using either one or both weapons bays. Such a shape could carry both cameras (with appropriate LO windows), passive ELINT sensors, and/or low probability of intercept active recce radar.

 

[Woody]

Thanks Elmayerle for the information. I'm always willing to learn - that's what I log on for.

Oh, the extensive sawtooth shown isn't necessary (take a look at the F-35's inlet, or that flown on the JIST testbed to prove out the theory behind it. The YF-23 didn't need vectoring nozzles, it already was as maneuverable as the YF-22 and the nozzles just add complexity and weight.

RE: the sawtooth thing, maybe we're getting tangled up in terms. Though the F-35 inlet doesn't exhibit rows of small saw-teeth the whole thing is a three angled-edged 'tooth' (it's definitely not square so what's a better term?) and the design features many more on its panel and door edges.

I agree there is no official information saying whether one competitor was better at maneuverability and there was about the USAF preferring Lockheed's management. But if the YF-23 was manoeuverable without thrust vectoring image how good it could have been with it!

Some pundits state the YF-22 had better range and others the YF-23. Most say the YF-22 was a more integrated product in terms on cockpit and systems. But the only info I've found on weapons load says the YF-23 could carry an air-to-air load of 4 AMRAAMs or 8 Sidewinders to the Raptors 6 AMRAAM and 2 Sidewinders (which I don't think is that great). Also apparently the missiles were stacked, raising fears that if the first missile jammed it would stop the one above. Please tell me more.

I wonder if the Air force would have had all that confidence in Lockheed if they'd know that they wouldn't have reached full operational status by 2007?

My own offering is an amateur's fantasy and I'm really not sure about the top mounted intakes, at least without some sort of demand activated door supplying air from underneath at high AoA. And fattening the fore-body would probably stuff up the aerodynamic concept. But compared to some of the ATF configurations offered I still think its cool.

Cheers, Woody

 

[elmayerle]

Well, my understanding is that thrust-vectoring is primarily useful at low speeds rather than high speeds; accordingly, if the aircraft is otherwise maneuverable enough, thrust vectoring is just added un-necessary complexity and weight. The shape of the F-35's is determined more by the aerodynamic requirements for removing the boundary layer without using your standard boundary layer diverter which adds greatly to the RCS. Having said that, a F-23 with inlets shaped like the JIST inlet would work nicely.

I'm not that familiar with all the aspects of the F-23's weapons bays, but I do believe that the racks of stacked missiles were extendable to allow either AMRAAM to fire.

 

[CammNut]

Having seen the YF-22 and YF-23 close up, I think it is clear why Lockheed won. The YF-22 was an aircraft, a true protoype of the F-22. The YF-23 was a plastic model of the aircraft that Northrop would have built had it won. And don't forget Lockheed flew an avionics demonstrator; Northrop and McDonnell did their demos on the ground. Risk, not performance carried the day. Unfortunately the risk was not as low as they believed.

 

[flateric]

Having seen the YF-22 and YF-23 close up, I think it is clear why Lockheed won. The YF-22 was an aircraft, a true protoype of the F-22. The YF-23 was a plastic model of the aircraft that Northrop would have built had it won.

With all my circuits on YF-23, I can't disagree.

And don't forget Lockheed flew an avionics demonstrator; Northrop and McDonnell did their demos on the ground.

Hmm, what then did Northrop/MDC do with that BAC One Eleven?

 

[CammNut]

I had forgotten Westinghouse's "Bac 1-11", but my impression at the time was that it was a principally a sensor testbed - a continuation of its work in support of the Ultra Reliable Radar programme - while the 757 was a demonstrator for the F-22's avionics architecture, and in particular for the sensor-fusion algorithms and "human-machine interface". It is my recollection that the cockpit demonstrations in support of the ATF were conducted on the ground for the Northrop/McDonnell team and, at least in part, in the air for the Lockheed/Boeing/GD team.

A similar situation exists today where the BAC One-Eleven, now belonging to Northrop Grumman, is a sensor testbed for JSF, but Lockheed has modified a 737-300 to be the F-35 avionics testbed.

 

[Woody]

Thanks Elmayerle.

Having said that, a F-23 with inlets shaped like the JIST inlet would work nicely.

Do you have any images/diagrams/links of the JIST intake tests? (I can only find committee reports) It would be great to update my virtual aircraft catalog without the need for so may jaggies.

I'm still a fan of 'low speed maneuverability" if by which you mean dog-fight maneuverability after the merge. I just found a JSF Power-point presentation and find it interesting that it describes the JSF as having 'F-16 "like" maneuverability'; the sensor and systems are great but so much for 30 years of aerodynamic development.

The image below shows one way to increase the missile load of a stealth plane - and they've got another pair of pylons they could use! ;D

Cheers, Woody

 

[Matej]

PS: Matej, I didn't use your drawing other than for possition but mine should fit over yours for comparison. Your drawing had a longer fuselage (obviously) but a skinnier rear and smaller tail surfaces than the original 3 veiw I worked from, any reason for this?

Yes. Skinner rear is some kind of optical effect of much smoother and integral fuselage than original YF-23 development prototype. For example the hump for the fuel and the bomb bays was lower, but its internal volume was bigger. Also the section in front from the cockpit was much fatter to acommodate powerful radar and all necessary equipment. Regarding to smaller tail surfaces - I found it as natural process, because the prototype had them oversized for additional stability during early flight tests. Just take a look @ YF-22, how big had it them.

Matej, if you want to add an alternate reconnaisance capability that was palletized, consider a shape similar to the lower front of TSSAM, both front and back, faired into the surface contours, and using either one or both weapons bays. Such a shape could carry both cameras (with appropriate LO windows), passive ELINT sensors, and/or low probability of intercept active recce radar.

Thats an interesting information for me and I think that also for the Nikolay.

Do you have any images/diagrams/links of the JIST intake tests? (I can only find committee reports) It would be great to update my virtual aircraft catalog without the need for so may jaggies.

If you have text, here are the pics: http://www.hitechweb.genezis.eu/fightersAP07.htm

But the only info I've found on weapons load says the YF-23 could carry an air-to-air load of 4 AMRAAMs or 8 Sidewinders to the Raptors 6 AMRAAM and 2 Sidewinders (which I don't think is that great). Also apparently the missiles were stacked, raising fears that if the first missile jammed it would stop the one above. Please tell me more.

I will not tell you anything, because it is better to see than hear.

 

[Woody]

Thanks Matej,

If you have text, here are the pics: http://www.hitechweb.genezis.eu/fightersAP08.htm

I will not tell you anything, because it is better to see than hear.

But when I click your link I just get an F-16 text page and my Slovak is still not as good as it should be.

The Weapon magazine arrangement you posted looks a bit clunky to me. I wouldn't like to try and fit a bunch of JDAMs up there.

Do you have any of the plans you based your F/A-23A on or are they super super top secret?

An expert like yourself has probably seen it but I've included a Youtube link to a great 1980s YF-23 promotional clip complete with dodgy 80s music:-

http://www.youtube.com/watch?v=FNKw9TrVviE

Does anyone else know where else on the internet you can get YF-23 video?

Cheers, Woody

 

[fightingirish]

Does anyone else know where else on the internet you can get YF-23 video?

Unfortunately the video "YF-23 "Declassified" is no longer available at You-Tube due to a copyright claim by West Coast Images. :-[

Parts 1-3 are history of Northrop designs, cold war climate, mission requirements, time and effort put in to the design, and manufacture process. Parts 4-5 have the role out, taxi tests, testing footage, surge day, the final decision and the two YF-23's final resting place. While it doesn't really declassify anything a good aviation enthusiast wouldn't already know and has a few factual errors here and there; it has some good interviews with the design team, Northrop CEOs, test pilots and video footage of the Black Widow II in flight.

Maybe someone downloaded it with a tool/program!

 

[overscan (PaulMM)]

It is a commercially available DVD. We should respect peoples copyrights here. Posting extracts or screenshots is one thing, posting the whole video is not fair to the producers of this DVD.

 

[flateric]

I must add that this DVD is pretty cheap for the wealth of info WCI guys put into it.

 

[elmayerle]

Thanks Matej,

If you have text, here are the pics: http://www.hitechweb.genezis.eu/fightersAP08.htm

I will not tell you anything, because it is better to see than hear.

But when I click your link I just get an F-16 text page and my Slovak is still not as good as it should be.

Well, if you go about 60% of the way down the page, he's got some excellent pictures of the JIST F-16 inlet. I've seen better, but those were part of my introductory briefing on the F-35 and I'm not sure how widely I'm allowed to distribute those.

 

[Woody]

Well, if you go about 60% of the way down the page, he's got some excellent pictures of the JIST F-16 inlet.

Thanks Elmayerle/Matej,
For some reason the pictures don't load on that page of Mataj's site when I use Firefox (maybe they don't for other people either). I just tried Explorer and it works fine.
I've seen this F-16 before but the smaller images of the inlet disassembled are very revealing as they don't appear to show any suction device for boundary layer removal though there is an interesting recess right at the front of the 'hump' which is covered when assembled. Do you know what this is for? The images in-flight look potentially retouched just around the intake area to this photochopper's eye, maybe to hide that secret bit?. And that chin spike is for aerodynamics only you say.
Thanks once again, Woody

 

[fightingirish]

Well, if you go about 60% of the way down the page, he's got some excellent pictures of the JIST F-16 inlet.

Thanks Elmayerle/Matej,
For some reason the pictures don't load on that page of Mataj's site when I use Firefox (maybe they don't for other people either). I just tried Explorer and it works fine.
.........

Ahh, now I know why Matej's site nevered shows pictures...

 

[flateric]

more on DSI/F-35 inlets

 

[Matej]

Do you have any of the plans you based your F/A-23A on or are they super super top secret?

As flateric mentioned in post no. 15, basic idea is from Koku-fan drawing. Other is my research and the good advices of my friends (a lot of them are already here at Secretprojects).

 

[lantinian]

Hi To All,
Special Regards to flaterick and .
If it wasn't for a friend, I would not have seem my picture of the F-23A weapons bay configurations posted. :

The ATF weapons capacity was one of its most debated issue of the program. "How many missiles to carry ?" was a question that was answered: 6 of existing design or 8 of new or modified design. The Existing missiles of the time were the AIM-9L and the AIM-120A. The New/Improved missiles were the ASRAAM and the AIM-201C respectively.

It's been found in practice that the F-22 is the first fighter that actually "runs out of missiles" on a regular basis and could keep on shooting down enemy aircraft if it had more. It so Ironic that its 2D trust vectoring nozzles and super maneuverability do not play any part in that "shooting gallery" type of story that happens in exercises. It has even ended up using its gun because of lack of missiles.

A conceptual flaw if you ask me.

Ever since I run across the Northrop Patent in Reply #28, some 3 years ago I was fascinated by the ingenuity of the design and the potential that it has.
1st. Its amazing how little space can 4 AIM-120A can take. You can never fit 4 like that on external stores. And some people thought that internal bays for aircraft meant less space for weapons. Only they forgot that internally carried weapons do not need forward launch clearance zone and can be placed much closer to each other.

2nd. lets analyze the launcher weight. We have a common launch mechanism and we have a common holding mechanism. Compare that to the weight of 4 externally carried pylons for all 4 AMRAAMs.

3rd. The potential it has when considering the AIM-120C with the clipped wings. If we look at the launcher as it is now we see that the wings of the bottom missile determine its proximity to the launch door in the same way the wings of the top missile determine the height of the mechanism. Similarly the wings on all missiles make the width of the whole launcher. Lastly the distance between the missiles are also limited by the wings. See a pattern. What if we are to clip those wings like on the AIM-120C variant?

If we are to design the whole mechanism around the AIM-120C, it will be 22% shorter and 35% narrower. In other words, you can say that 3 of the new launchers will fit on the place of 2 of the old ones. The F-23 weapons bay is almost as tall as it is wide as seen on the declassified video footage. If it were designed to carry 2 of those launchers with 2 AIM-120A each (the minimum), it can easily be modified to carry 3 with 3 AIM-120C each. That’s 9 total.

However this concept has its critics which say: A jam in one of the missiles will render the other above it useless. This is funny to me as missile launchers are hell of a lot less complex than engines yet some fighters have single engines. And the Lockheed 1985 wining ATF proposal had a revolving launcher. If it failed all the missiles might fail to launch save only one!

Looking at bays for the short range missiles, the F-22 has 1 for each Sidewinder missile. A sidewinder must be a dams important weapon for the ATF to have is own weapons bay. :-\ . Fitting two missiles is a lot more difficult as they have to be extended sideways and the wings cannot overlap. At least Lockheed designed it for access panel for other things too.
The F-23A had a dedicated short missile weapons bay. It can also carry a total 2 Sidewinder missiles. Converting it to carry 3 missiles (AIM-9X or ASRAAM) could be as each as the F-22 conversion from 2 A models to 3 C models of AMRAAM in its each main missile bay.

All in the F-23A with a slight change in the launchers could carry 4 more missiles or 50% more than the F-22A

A pics of all that will come shortly

 

[Matej]

Here

 

[PMN1]

I remember reading an article a few years back (cant remember the magazine right now) that suggested a link between the YF-23 and a Black Project possibly the alleged Aurora.