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Author Topic: Northrop/McDonnell Douglas YF-23 and EMD F-23  (Read 425180 times)

Offline kilokb

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1065 on: November 08, 2016, 07:44:47 pm »
Which is why I said "very little"versus none..... there is a smattering here and there.... but it really doesn't illuminate the build process as a whole. I can think of several articles with images of fus section being shipped, joined and tested as well as  wing build up and installation. Even primer ed roll out for the LM GD birds
Just interesting to me that  one is pretty well out there, while the other still seems pretty dark... so if it is "obsolete" ???......

Offline Steven

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1066 on: November 13, 2016, 05:40:50 pm »
I think I've read that the A-12's straight trailing edge gave a substantial RCS spike directly front due to surface diffraction and creeping wave returns.

trailing edge returns are actually dominated by edge diffraction contributions in the specular direction if edge alignment is the major concern (ie. concern over straight trailing edges)... the magnitude of the rcs contribution of the edge diffraction can be approximated by the length of the edge squared divided by pi (see equation 7.54 in ch.7 in "Introduction to the Uniform Theory of Diffraction", McNamara/Pistotius)...

with regards to edge location with respect to the incidence direction, trailing edges contribute an edge diffraction return when the electric field is polarized perpendicular to the edge (which can occur for linearly polarized waves where the E field is perpendicular to the trailing edge, or for circularly polarized waves where a component of the E field is perpendicular to the edge, figs. 7.6 and 7.8 in "Radar Cross Section", Knott/Shaeffer/Tuley)...

trailing edge diffraction actually drops considerably when viewed directly head on but rises quickly to the approximate value length^2/pi when the view angle rises slightly (see fig. 14.7 and accompanying discussion in "Radar Cross Section", Knott/Shaeffer/Tuley)...

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in contrast traveling waves (ie. surface waves if on surfaces exposed to the incident radiation, or creeping waves if on surfaces shadowed from the incident radiation) would reflect back at a surface discontinuity (ie. current discontinuity) regardless of edge alignment but their contributions are typically on the order of the square of the incident wavelength and thus are much smaller compared to the edge diffraction return in the specular direction (ie. direction normal to the edge), traveling wave contributions are thus normally mitigated via surface RAM and/or materials to taper the currents as it nears the surface discontinuity (since it is the discontinuity of the currents at the edge of a surface which causes the reflection of the traveling wave to occur)...

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given the difference in relative magnitudes of the two contributions (ie. "length^2/pi" for edge diffraction vs. "wavelength^2" for traveling waves), if edge alignment was the major concern (ie. straight edges were used) then it's likely the major concern of contribution was the edge diffraction return (under the assumption that short wavelengths were under consideration, and also under the assumption that the trailing edge was actually a metal structure, and not a dielectric covering a saw-tooth metal edge underneath)...

Thank you for the details.

Offline Ogami musashi

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1067 on: December 22, 2016, 02:58:52 pm »
Those images are from the book air force legend: YF-23. They were published by Aldo Spadoni on the TGPTNW facebook(the author of those illustrations back in the 90's)


You can see the actual cockpit that was proposed both for ATF-23 and NATF-23.

In the book are several pictures of Tony Chong's model of a near DP 232 (F-23 EMD proposal with F120-GE-100) as well as technical drawings for DP232 and DP231(With F119-PW-100) including with some corrections (the fuselage/nacelles blending was altered) and explanations for the dual weapon bays, the new intakes as well as the "fill in" between the recontoured nacelles.

« Last Edit: December 22, 2016, 03:05:11 pm by Ogami musashi »

Offline Steven

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1068 on: December 22, 2016, 06:19:14 pm »
So now it appears that the "fill in" between the nacelles is done so to compensate for the smoothed out nacelles so as to largely maintaining the area ruling of the YF-23. It would also appear that the leaked Koku Fan diagram of the F-23A represents DP232 with the F120 engines, based on the extra serration on the trailing edge of the fuselage.

Offline Ogami musashi

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1069 on: December 23, 2016, 04:16:02 am »
So now it appears that the "fill in" between the nacelles is done so to compensate for the smoothed out nacelles so as to largely maintaining the area ruling of the YF-23. It would also appear that the leaked Koku Fan diagram of the F-23A represents DP232 with the F120 engines, based on the extra serration on the trailing edge of the fuselage.

Probably DP201 (tony chong model) as koku fan drawing still has the straight chine in the fuselage and the roll out ceremony was 06-90 while the DP232 drawing was from 12-90.




Offline lantinian

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1070 on: January 30, 2017, 03:56:47 am »
While the experts here won't find anything new, I found this YouTube clip to be worth watching and a good short summary and a great starting point to explore the YF-23 topic

« Last Edit: February 01, 2017, 12:02:37 am by lantinian »
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Offline FighterJock

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1071 on: January 30, 2017, 05:08:01 am »
Here is an other F-23 video that I have just found on YouTube, this time featuring test pilots Paul Metz and Jim Sandberg. I hope hat no one has posted this video on this thread before.


Offline flateric

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1072 on: January 30, 2017, 05:12:28 am »
Here is an other F-23 video that I have just found on YouTube, this time featuring test pilots Paul Metz and Jim Sandberg. I hope hat no one has posted this video on this thread before.
Why not try to search?
http://www.secretprojects.co.uk/forum/index.php/topic,1092.msg258520/topicseen.html#msg258520
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stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline FighterJock

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1073 on: January 30, 2017, 05:14:14 am »
Thanks flateric.  :-[

Offline Ogami musashi

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F-23 weapons bay
« Reply #1074 on: February 18, 2017, 04:47:13 pm »
After some thoughts, i can't get my mind on how the weapon release in the F-23A would work. Let me explain:

- On the YF-23 PAV-1, there was a complicated plater+launcher system. The Utility manual says that the palet was outward angled by 17 degrees. In Paul Metz book, the YF-23 drawing indeed depicts two amraams in the weapon bay being angled at approx 17 outward.

-The problem is that, IMHO, this system can't work on the F-23A. The two missiles on the YF-23 were located at the center of the bay, while on the F-23A you had 4 of them with two outward and on top of two other(see aldo spadoni illustration above). The weapon bays on the F-23A were shallower and more importantly there was wing bulkhead that basically prevented the lower missiles to be rotated.
The two files attached show the 4 missiles arrangement on the F-23A and the YF-23A arrangement as put into an F-23A weapon bay.


-Since you can't rotate the lower missiles, then, only four hypothesis:

1/ The weapon palet tilts down to fire the upper missiles. This seems impossible for two reasons: the bulkhead will prevent the lower missile to rotate unless lowered outside of the weapon bay (see point 3) and even though, the upper missiles can't be fired without being extended (their wings would collide with lower missiles fins).
2/ You can't select the munition and lower missiles are first launched. This would seem plausible because the plane has one weapon bay for amraams and one for sidewinder. Except that in technical drawings, in the specifications table, you have an alternative weapon load offered. And this is still has only amraam and aim-9 as possibility. At the time of the proposal, the aim-120c program wasn't officially launched and as confirmed by Aldo spadoni, aim-120c fitting in the F-23A was only remotely researched so the proposal didn't feature those. I think one probable loadout was a 4 aim-9 and two aim-120 missiles. In that case, not being able to select the munition is clearly impossible.
3/ The whole loadout is exposed to the air. This would be pretty strange for a plane that put so much attention to stealth that the whole pylons+missiles would be in the stream!
4/ The rest of all solutions!

Anyone has some idea, info?
« Last Edit: February 18, 2017, 06:47:19 pm by Ogami musashi »

Offline Ogami musashi

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1075 on: February 19, 2017, 04:15:31 pm »
Had my answer by Aldo.

The F-23A had no weapon station selection because, at the time of the proposal, it was only envisaged to use similar missiles per bay. So you would first fire the lower missiles then the top ones.
But the F-23A would have had to have a AG capability so in this case JDAMs would have been carried on one side and aim-120 on the other.

As such it appears the moveable palet of the YF-23 was not kept on F-23A.

Aldo told that USAF preferred the F-22 weapon arrangement as more flexible even if the vertical stacking on the F-23A was more stealthy with less weapon bays doors and less edge sealing.

As always, aldo, just as tony chong, stress that this was the system used on the illustrated proposal hinting that this was probably not the only and definitive proposal.

Offline lantinian

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1076 on: February 20, 2017, 02:18:50 am »
I believe F-23A could have employed a similar AIM-120C trapeze launcher like F-22A has but instead of 3 per bay, would have carried 4 or 5 (as there was no wall separating the bay into 2 sections)

Same in the smaller bay upfront. Because it's was 1 bay, they could easily have fitted 3 AIM-9X in the place of 2 AIM-9M.

Further, as the main bay was deeper, each weapons bay door could have carried not just 1 AIM-9M, but maybe two 9X or 120C on a similar launcher but without the trapeze mechanism.

So that a total load between 9 and 12 missiles.

I fully agree F-22 had a more practical weapons launcher design but it's pretty easy math to see F-23 had a bigger and potentially much more versatile weapons bay.

It could have even been modified to carry 2000lb JDAMs in the main bay by sacrificing all other missiles.
We have to shape the future or others will do it for us.....Cdr. Ivanova, Babylon 5

Offline Ogami musashi

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1077 on: February 20, 2017, 02:23:07 pm »
I don't think any of this is possible since the main weapon bay has a bulkhead that prevent stacking the missile longitudinally like on the F-22. There's room for 6 aim-120C, room for probably more than 2 jdam1K while keeping at least 2 aim-120C, and there's even room for two Jdam 2K but missiles on weapon bay doors was excluded from the proposal as not stealthy (this was one of the reason for going from 1 deep wb to 2 on the emd) and 9 to 12 is probably too much because you need to have sufficient room for the launcher to reach their missiles. That being said if the articulated palet like on the YF-23 was used, using assymetrical weaon carriage like aldo said, you can have pretty interesting mixed weapon arrangement because the palet had the role of imparting a specific movement direction before the launcher extended.

Offline lantinian

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Re: Northrop/McDonnell Douglas YF-23 and EMD F-23
« Reply #1078 on: March 02, 2017, 09:22:30 pm »
I don't think any of this is possible since the main weapon bay has a bulkhead that prevent stacking the missile longitudinally like on the F-22. There's room for 6 aim-120C, room for probably more than 2 jdam1K while keeping at least 2 aim-120C, and there's even room for two Jdam 2K but missiles on weapon bay doors was excluded from the proposal as not stealthy (this was one of the reason for going from 1 deep wb to 2 on the emd) and 9 to 12 is probably too much because you need to have sufficient room for the launcher to reach their missiles. That being said if the articulated palet like on the YF-23 was used, using assymetrical weaon carriage like aldo said, you can have pretty interesting mixed weapon arrangement because the palet had the role of imparting a specific movement direction before the launcher extended.
The F-23A proposal did indeed had 2 bays and they would have likely seen further refinement to accommodate A2G weapons like the update F-22A undertook around 1994.

In terms of how the weapons could be stacked (an idea, not a reference to an actual proposal), since 2007 I have been referring to an approach, now used by Boing in its weapons pod proposals for the Super Hornet. This approach allows for firing of any weapons in any succession without complex launch arms or pallets.

You can easily make an argument that F-23A larger bay was wider than the Super Hornet pod and has doors that can support heavier loads. Essentially, in terms of potential for weapons and configuration, I believe the F-23A main bay could have been updated to be like 2 Super Hornet pods put side to side.
« Last Edit: March 04, 2017, 03:29:09 am by lantinian »
We have to shape the future or others will do it for us.....Cdr. Ivanova, Babylon 5