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

[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! 

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:-



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!