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

Ogami musashi said:
F-23 would have had far closer nacelles spacing; I wonder if that was really an unsolvable problem;


I actually browsing archive to try and found when did the requirement for supercruise range went down but have trouble finding it; back in 95 the F-22 was still planned to make 15 tons empty (even with the approved weight increase) so that's probably somewhere between 95 and 99 that requirements were lowered; Another possibility is that requirement were relaxed far before probably in 92..
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I wasn't aware that the nacelles on the F-23 would be any closer, and don't really see it in sketches of the proposed production variant. As I recall, the major changes to the shape were:

1. Radar nose ('natch)
2. Redesign of the inlets to incorporate the fixed conical centerbody and revised shape.
3. Increase in length sufficient to allow for the forward missile bay.
4. Reduction in the size of the engine housing since there was no longer a need to provide streamlined, stealthy space for the thrust reversers and their associated operating mechanisms. You can see this in the silhouette posted by Radical and in other depictions of frontal views of the F-23. The actual engines, though, weren't any closer together AFAIK; that would be a major redesign.
5. Revised exhaust treatment. The YFs used a design for IR suppression and heat dissipation that was unique to them that didn't work as well as ultimately would be needed and would require unacceptable levels of maintenance. Reportedly, Northrop/MDD had known and acknowledged this from the start. They had a revised design using different material that was proposed for production. They would also have additional cooling available. However, it would involve some significant chunks of change to fully develop. They didn't want to spend the money to do that unless they had the production contract, so they opted for a short-lived system that would demonstrate the capability but only needed to last for DEM/VAL.

Regarding relaxed requirements for the F-22, I believe this has been discussed under another topic. Basically, in the early '90s it became apparent that of the expected performance in speed, maneuverability and range, the F-22 would be able to meet any two of the three, and the choice was to relax the range goal.
 
They were indeed.


Just by the fact the engine centerline was 1,5° out of the plane center line (I.e: engines were going inward ) and the engine nacelles themselves were closer which led to redesign of the aft section much narrower than on the YF-23.




You can see that with ease in sundog's drawing in scott's APR.
 
I'll look tonight when I return to my cave. :D
 
F-14D said:
5. Revised exhaust treatment. The YFs used a design for IR suppression and heat dissipation that was unique to them that didn't work as well as ultimately would be needed and would require unacceptable levels of maintenance. Reportedly, Northrop/MDD had known and acknowledged this from the start. They had a revised design using different material that was proposed for production. They would also have additional cooling available. However, it would involve some significant chunks of change to fully develop. They didn't want to spend the money to do that unless they had the production contract, so they opted for a short-lived system that would demonstrate the capability but only needed to last for DEM/VAL.
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I don't know, it had some interesting features...
 

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That is interesting.

As we've often seen in low observable technology, function defines form. Northrop have used this chevron planform for exhaust decks on at least one other stealthy aircraft but I've never seen a close up shot of the B-2 from the angles shown above... has anyone else?

I'd be surprised if a similar array of slots (as seen on the lower surface of the YF-23 exhaust) are present on the B-2A, I do however, like surprises.
 
Hi guys... I have named Scott Lowther as the single greatest contributor to the YF-23 community for his outstanding APR publication and recent GE YF120 walkaround. More details at my site...

APR Award.jpg

http://www.yf-23.net/award.html#APR
 
Just spotted what could a blooper in Steve Pace's book F-22 Raptor - America's Most Lethal War Machine, published by Aviation Week (McGraw Hill).

In that book, he claims that the Northrop/McDonnell Douglas YF-23A bore the inhouse designation "N-14".

However, other sources have made it clear that "N-14" was given to a pre-B-2 bomber project for the USAF's ATB program, not the ATF!

Any idea, folks? Maybe BillRo could help us out on this one?
 

<...> introduced Bob Sandusky '57. Bob has been called an 'honorary class of 1957 member' because he didn't actually graduate with the class. He would have had it not been for his family moving out of the area at the beginning of his senior year.
But Bob has always considered West his Alma Mater, regularly attending the class of 1957 class reunions.

Bob told the group he got interested in airplane design at West when his drafting teacher, C.S. Kennedy, pulled out some plane pictures one day in class and told Bob to 'look at them!'


Bob has over thirty years of experience in aircraft design working at Boeing and Northrop. His is the first named inventory on both the F-20 Tigershark and the YF-23A Advanced Tactical Fighter. He was appointed Professor of Engineering and Applied Science for The George Washington University at the NASA Langley Research Center in Virginia. Bob now resides in Yorktown Virginia with his wife, Marcia
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http://www.westhighalumni.com/cafateria_elements/2011%20HallofFame.htm
 

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I went to Factory Direct Models online and its MSRP is $211.95 and the Factory Direct Models price is $149.95. -SP
 

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DonaldM said:
Are Factory Direct Models considered "official" like models manufactured by Verkuyl, Precise, or Topping?
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No, these are all Philippine-made and available to the public for as long as there is a demand. Aerospace manufacturers may collect a licensing fee, especially if their name is Boeing, but do not check for accuracy, etc.

Topping models were not sold to the public -- only to manufacturers, to be offered as corporate gifts for those involved with the programs. Robert McNamara killed that practice (and most of that industry) through another one of his questionable legislations.

The closest thing remaining to an independent model maker is Pacific Miniatures (PacMin), who contracts directly with aerospace manufacturers and uses their original CAD files to make extremely accurate tooling for the models.
 
Model of Northrop YF-23 given to employees who worked on the program found on eBay.

Seller's description:
ATF Northrop YF-23 USAF 800. This model was given out to employees who helped with design. It is a 1:72 model and never came with a box. This is in great shape, the color variation in the picture is dust and can easily be wiped off. The model does have some yellowing from being on display. It makes it appear more brown than grey, but still looks really good.
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Source:
http://www.ebay.com/itm/ATF-Northrop-YF-23-USAF-800-/330796104133?pt=LH_DefaultDomain_0&hash=item4d04fbf9c5

NOTE: The model is dusty, not a different paint scheme.
 

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Is it just me or does the fuselage (nose section) of the YF-23 appear to be attached to the wings instead of the wings being attached to the fuselage (nose section)? -SP
 
Maybe I missed it somewhere but does anyone know the N number and/or P number of the YF-23 airplanes? -SP
 
Steve Pace said:
Maybe I missed it somewhere but does anyone know the N number and/or P number of the YF-23 airplanes? -SP
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No. I have seen the designation DP117K for the YF-23A, but I seem to recall some blueprint carry a number beginning with "400-" which could indicate "N-400" as the designation, but that's only speculation on my part.
 
N- numbers were restarted by the Northrop Black Projects team. It will probably have a low N- number, above 14.
 
Paul is correct - the Northrop N- number ledger stayed with the white world Advanced Design team who continued with the numbering sequence, while the black programs - B-2, Whale and YF-23 etc? started with a new numbering system.
 
Thanks guys - it'll nice to discover these numbers when they finally come to light. -SP
 
I was the producer of this YF-23 model. We had a mandated price of $9.99 so in order to keep the price down they were delivered with only the canopy painted. Decals were in the box for both the GE and PW versions.
The base was hot stamped with the Northrop Grumman logo and the YF-23 name. I made 10,000 of them........whew! Each was also hand painted grey due to color variations in the injected plastic. Was easy to paint one side, wait till dry, and then paint the other. I then painted the canopy with a special gold lacquer that dried quickly. I had a paint mask to allow for fast paint application. I also made the 2nd release of the B-2 and the Super Tucano.


Needless to say we were crestfallen when that ugly Lockheed plane was selected. Plans were to make 25,000 more models.
 
Thank you for verifying that the model is authentic, allysonca. Thank you also for telling us the story of its creation. B) Was this model manufactured at the Northrop Grumman model shop? I would also be very interested in other anecdotes that might share.

Super Tucano model? Northrop Grumman might have manufactured the Super Tucano?
 
allysonca said:
Needless to say we were crestfallen when that ugly Lockheed plane was selected. Plans were to make 25,000 more models.
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I can imagine! The YF-23 seemed to have so much going its way... except politics or close bureaucratic connections, maybe?
I'm still waiting to read an unbiased, official account on how superior the F-22 was over the F-23.
 
The models we made derived from a 1/72nd super master model in the same scale. An aluminum mold was paragraphed from this master. We chose this material as a cost saving measure as steel would have been too expensive. The base was from an existing Northrop mold.

Decals were provided for both the Pratt and Whitney and GE versions.

As I previously mentioned we had a huge problem with plastics flow that resulted in an uneven coloration to the model. The solution was to use an FS color matched laquer that was applied 2 applications, one on the top.... rotate .... and paint the bottom. We used conformal printing in the base. When we did the B-2's the methodology had advanced and we were able to conformal print these as well.

The super Tucano was done the same, with the exception that the white flowed with no issues. Decal for Navy and Air Force were included in the box, and we used the same base as the YF-23, Again I used a paint mask to apply a blue toned canopy to the model. We started the project with a 4 blade prop and had to change to a 5. Sadly Northrop lost this project as well.

All in all we produced 10,000 of the Yf-23's, and 5,000 B-2's and if I recall correctly 1000 Super Tucanos.

If the Company needed a presentation example, the model shop they did their magic to super detail one of the "stock" models.

As an aside there was a story floating around that out at Edwards one of the test pilots took another pilots young son for a ride in the Tucano. During the ride the kid pulled the seat lever somehow and punched out. Plane landed as did the kid... alive and with a story to tell to his kids someday.
 
Actually, the AT-6 was excluded without notice and the Super Tucano "won". However, Beechcraft filed suit against the decision and the program was stopped. There's supposed to be a second "selection" but I don't believe that has even been opened though both manufacturer's continue to refine their potential entries.

Enjoy the Day! Mark
 
I’ve been teaching myself sketchup for hobby applications and I thought about looking into the F-23’s weapon bay geometry to see how many AMRAAMs could actually be crammed in there. A couple of caveats:
1. I’m still very new to sketchup and CAD work in general
2. I was super tired last night so the models are a bit sloppy
3. The plans come from Scott’s Aerospace Projects Review electronic addendum. While these are excellent the plans they appear to be scanned from actual blueprints and thus have some distortions in the reproduction. They also aren’t high enough resolution to scale up without too pixilation.

That all being said I think I was able to come up with pretty decent models of the bay (the missile models are very accurate). From what I can tell, without knowing the actual launcher technology to be employed, it would have been very difficult to fit more than two AMRAAMs in there without a redesign of some of the structural components in the bay itself. The most limited factor is the wing-join bulkhead in the aft of the bay. It greatly restricts the aft bay volume and prevents vertically stacking three AMRAAMs on each side (yes I understand that the vertically stacked arrangement was a Northrop patent unrelated to their ATF bid.)
F23WeapsBay1.jpg

F23WeapsBay2.jpg

I tried to mess around with various configurations and despite the great bay volume, the bay door design and the wing-join bulkhead greatly restrict separation clearances. Perhaps others can see these photos and suggest an alternate configuration but the closest that I could get is the fit two AMRAAMs vertically (like the patent) with an additional one to the side. There’s plenty of room in the bay to fit this extra missile but the big question is the door actuators. They protrude into the bay about 6” (the dashed line represents how far into the bay they go) but if there’s just two of them it might work. If there are more than two then it won’t work and being that the prototypes had at least three I’d say that’s a high probability.

F23WeapsBay4.jpg

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That's a really interesting exercise BDF. :) I applaude you for using something a lot of people are passionate about to develop your CAD skills.
Because I've been staring at the YF-23/F-23A weapons bays for hours myself (got them printed on the wall), I would like to offer you the following observations.

1. From the unclassified F-23A plan few - left side, the main weapons bay does appear to have such bulkhead preventing you to stack the missiles this way

2. The bay the forward bay door actuators are visible on Cuts J and K and since the way the rear door open the same way, the actuators should look and be positioned similarly.

3. The famous Northrop stacked AMRAAM missile launcher makes practical sense if you have vertical space for at lest 3 missiles, preferably 4. The F-23A weapons bay is a lot shallower than the YF-23 one, so I believe Northrop might have meant to implemented this trapeze launcher instead. [link]http://www.google.com/patents/US6250195[/link] It would have allowed for wider range of weapons to be launched.

4. The bay doors themselves were each capable of mounting 1 AMRAAM toward the opening, which may explain why the middle section of the main bay if deeper.

5. Rather then stacking the missiles vertically as they were on the YF-23, try misaligning the them like on the F-22A. You should be able to fit 4 on the inside of the main bay with extra 2 mounted on the bay doors.

7. I'd be interested to see if fitting 2x 1000lb JDAMs would still allow for any other AMRAAM to be mounted in the bay.

The reason I believe this is the best configuration is failure in any of the trapeze launchers to deploy would not affect the ability to of any of the others to do so.

Good Luck!
 
I’ve wrestled with this a little more. I didn’t go through great lengths to make good models just extruded some of the cross-sections and then connecting them. To be succinct, there’s no room in the forward Sidewinder bay to nose an AMRAAM into. So the only way I think they could fit a third AMRAAM into the bay would be to mount the third along the longitudinal bay wall and have some sort of trapeze or an angled ejection (sort of like how an F-15 ejects AMRAAMs off the cheek missile stations. The problem is that there is a very small window to shoot that missile through during the ejection process; approximately 21” of clearance at most. I’d be very interested to see how Northrop’s engineers planned to accommodate the ATF requirement. I should also point out that that aft wing-join bulkhead would prevent carriage of a GBU-31 too.
WeaponsBay5.jpg


WeaponsBay6.jpg

WeaponsBay7.jpg
 
F-23 weapon bay is shallower than YF-23? I thought F-23 area ruling was not as strict compared to YF-23 in order to accommodate the weapon bays.
 
EricChase88 said:
F-23 weapon bay is shallower than YF-23? I thought F-23 area ruling was not as strict compared to YF-23 in order to accommodate the weapon bays.
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The YF-23 weapons bay had to handle the long and short range missiles. IIRC, the long range AAM's were mounted within the bay and the SRAAM's (Sidewinders) were the missiles mounted on the doors. But the USAF didn't like that, because they said a missile jam could keep the rest of the missiles from firing, though they never explained how.

So for the F-23, the forward fuselage was lengthened and instead of one deep missile bay it had two shallow missile bays. The one where the YF-23's bay was located still housed the LRAAM's, but the smaller bay just ahead of it handled the SRAAM's.

I'm not sure where you got the idea that the F-23 wasn't area ruled as well as that of the YF-23. In many ways, the aerodynamics of the F-23 seem much more refined than those of the YF-23.
 
the long range AAM's were mounted within the bay and the SRAAM's (Sidewinders) were the missiles mounted on the doors. But the USAF didn't like that, because they said a missile jam could keep the rest of the missiles from firing, though they never explained how.
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I think USAF had an issue with a single combined trapeze launcher for all missiles, where if the opening mechanism failed, no missle could be fired. Also if some of the bottom (outer)missiles failed to launch, the top (inner) ones could not launch too.

That would explain the 1999 Northrop patent where every weapon gets its own trapeze launcher.

I think the door mounted pylon could launch either Siderwinder or AMRAAMs.
 
Has the cross-sectional area plot of the YF-23 ever been released? Wierd they release the F-23 EMD plot but not YF-23.
 
The cross sectional area of the YF-23 was published in certain Northrop dwgs, but at this stage I'm not at liberty to elaborate more precisely. I can say that if you carefully study what has been publically released so far, you will see that the YF-23 did indeed conform more closely to the Area Rule than did the final F-23 configuration. This is because the fuselage shape of the YF did not have to accomodate equipment that would be installed on the production variant, so the 'waisting' of the fuselage could be more pronounced. The F-23 fuselage is thicker and more voluminous in certain areas to accommodate more weapons and fuel, particularly right at the wingtips, which is where you usually want it to be the slimmest. If you carefully scrutinise the YF in profile, you'll see that the longitudinal synchronisation between the wingspan and "waisting" of the fuselage is one of the most precise ever flown. In most area ruled aircraft, there is stagger between the extremeties of the wingspan and the narrowest point on the fuselage, but with the YF, you could draw a line laterally from the very centre of the wingtips and it would pass almost directly thru the narrowest point of the fuselage. This is very unusual.
 
The previous comment made me look around for a LIKE button.

I always thought that if we compare the YF-22 & 23 cross section diagrams of how the frontal area increases from tip to toe we will see a correlation to their supercruise speeds.
 
I think the lack of stagger is because the wing is essentially unswept at 50% chord, so its cross-sectional area contribution isn't spread out along the longitudinal axis as it is with more typical designs. In other words, my guess is that the correlation in the waisting you noticed is directly related to its equally unusual wing planform.
 
I the wing own geometric center is also unusually close to the aircraft's own one.

It is as if Northrop started with the wing then attached the front fuselage and the engines to it. The wing high front and rear sweep helps created even more structural link points.

The wing and not the fuselage being the main structural element is not surprising given Northrop's other big project at the time: B-2
 

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