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

[donnage99]

Here's a question that is bugging me.  The weapon bays of the yf-22 were placed well behind of the inlets, yet members of congress were still concerned that the smoke coming from firing missiles could mess with its engine through the inlets. This prompted Lockheed to have a missile firing demonstration from both the main bay and side bay.  And now we talking about the yf-23, which has its main weapon bay even closer to the inlet, and the planned inlet for the sidewinders which is even before the inlets (so the rumour goes).  I'm wondering why was Congress not concerned about Northrop airplane? 

[PaulMM (Overscan)]

Lockheed added weapons firings to the schedule, it wasn't a required element. It is possible that they did have concerns about the YF-23 as well, but the YF-23 demonstrator could hardly have demonstrated front weapons bays it didn't have.

[flateric]

What the source of the fact that Congress was even bothering of ATF 'smoke' launch problems? If they were giving a f**k of that, they'd better bother about acoustic loads and wave interference between airframe and missile exhaust plume (these were *real* problems).

[donnage99]

What the source of the fact that Congress was even bothering of ATF 'smoke' launch problems? If they were giving a f**k of that, they'd better bother about acoustic loads and wave interference between airframe and missile exhaust plume (these were *real* problems).

From this book (and after rereading it, I found myself making a mistake.  The book says members of the Gov. not Congress.  My apology):
http://books.google.com/books?id=5To910D9ASIC&pg=PA61&dq=yf-22+weapon+smoke&lr=&as_brr=3

I heard some guy who claimed he worked on the yf-23 and later moved to work on contract for the f-22 said this.  He was arguing another guy who said that one of the reasons yf-23 lost because it didn't demonstrate as aggressively as yf-22, citing missile firing demonstration on the yf-22.  I never taken what the so-called engineer said until I found the book that said something similar. 

[lantinian]

the smoke coming from firing missiles could mess with its engine through the inlets.

Consider the design of the F-14 and SU-27 and you will see these planes to be even more prone to such effects than the YF-23, which had its intakes widely spaced apart.

The YF-23 missile launcher was quite capable of making test launches of the AIM-120. In fact test were made with the missile extended almost fully out in the airstream. This way Northrop could simulate unlimited times missile launch without dropping the missile itself.

There was no requirement to perform actual missile launches. There was a requirement however to provided verification data regarding the launching mechanism.

The reason the YF-22 team did that (I think) is because that was the only way to provide the same kind of date the YF-23 team did. Remember how the YF-22 launcher works. The missile cannot be extended into the open and then dropped. Instead, it was pneumatically ejected. So, you cannot test that effect without dropping the missile. And they did eject the missile for the test. It was not really a big deal to make the missile fire its engines afterwords.

The approach by Lockheed made for a very powerful pro YF-22 argument to those not familiar with the actual tests. Actually Northrop tested its simulated missile launches and weapons bay performance at speeds up to Mach 1.5, while Lockheed made all test launches subsonically.

Consequently F-22A did have redesigned weapons bay since the old design could not operate well supersonically. Needless to say the F-23A didn't. It had the same main weapons bay door design.

All in all both teams demonstrated the most critical part of their missile launchers. For YF-22 that was the pneumatic missile ejection and for YF-23 that was bringing the missile from a storage position to launch ready one.

This plane would have been the best F-14 replacement. Better than the F/A-18 Superhornet and the F-35 JSF although some years older.

Yes, it was a bigger airplane all right. But at what cost would it have fully worked? The only thing one could argue is that Northrop/MDD have a lot more carrier experience that Lockheed/Boeing/GD

[donnage99]

You missed the point, Lantinian.  Yes, they both did hours of testing with their firing mechanism, obviously, but the point wasn't about concern for the approach of the missile firing machanism.  It's fear of an engine flame out with the smoke from the missile comes in through the inlet.  You can't do stimulation with this.  My question was that I find it odd that they were afraid of a flame out with yf-22 but not yf-23, which had much closer weapon bay toward the inlets.

My guess is that it was more of a concern with the engines rather than which airframe it was.  So with Lockheed demonstrated that a flame out wouldn't occur with the engines, Northrop didn't have to do the same, since they both used same engines.  My other guess is that it was never a formal request, but rather just concerns of critics and oppositions of the ATF program within the government (usually they are not even in the program), much like some folks in the Gov. are now raising concern about the tumblehome design of the Zumwalt Destroyer.  And Lockheed just did it for propaganda reason or something.   
 

[lantinian]

In YF-22 the missile bay is directly below the inlets. In YF-23 the bay is between the inlets. The YF-23 need not push its missile out of the way to avoid hot gas injection. Check the Front views of the two aircraft.

[flateric]

Look at the pic. You will note that YF-23s weapon bay doors perfectly serve as deflectors of exaust plume both from AMRAAMs launched from retractable 'cradle' (other dubbed it 'cigarette pack') launcher moved into airstream (launch method in case of YF-23) and AIM-9s, launched from launchers installed on bay doors close to the edge. So in the case, YF-23 was superior to YF-22 with a cheek Sidewinders launchers. In the case of F-23A, with a additional AIM-9 weapon bay forward to AMRAAMs one, it would be a problem. I've asked a question to Pavel Bulat, why is a gury in wave dynamics and weapon bay aerodynamics. Let's see what he will say.

[lantinian]

There your ultimate unofficial YF-23 guru answer   

[donnage99]

Thanks, guys! And hopefully, Pave Pulat may know something.

[flateric]

Rooney said his team was not concerned with the Lockheed team's decision to fire Sidewinder and AMRAAM
missiles, which he says were not a requirement of dem/val. "We make a list of what we feel is important and
we didn't share our list with Lockheed ... and they didn't share their list with us," he said. "We didn't think that
launching a very mature missile at seven-tenths Mach in level flight had any meaning whatsoever. (We) were
concerned about ... the environment in that weapons bay at very high speeds."

[donnage99]

Rooney said his team was not concerned with the Lockheed team's decision to fire Sidewinder and AMRAAM
missiles, which he says were not a requirement of dem/val. "We make a list of what we feel is important and
we didn't share our list with Lockheed ... and they didn't share their list with us," he said. "We didn't think that
launching a very mature missile at seven-tenths Mach in level flight had any meaning whatsoever. (We) were
concerned about ... the environment in that weapons bay at very high speeds."

Did you get this from accessmylibrary? I had read that a while ago, but totally forgot.  Thanks for reminding me.  So I'm guessing that it was only unwritten concern and not a formal request, and Lockheed did it just for propaganda reason. 

[flateric]

unwritten concerns sometimes worth more than written ones, but I think it was the other case

[donnage99]

unwritten concerns sometimes worth more than written ones, but I think it was the other case

I meant unwritten concern from the people who aren't even part of the evaluation team.  If you look through history, these people existed in every programs.  The reason is because they dont have full access to the program, they aren't aware of the technology used to overcome certain challenges, thus raising their concerns.  Just look at the Zumwalt tumblehome concerns, the f-35's air to air capabilities concerns, etc.  Back when the yf-22 came out, they were concerned that it wasn't stealthy enough at all.  Most the time, the people in charged of the program just shrug it off, but sometimes they'll do something about it if the voices get too noisy. 

And what do you mean by the other case? The engine case? The article you provided seems to be in line more with the non-formal concern, though.

[flateric]

as Paul Metz once said - not exact citation, but factually close -'we <at Northrop> still can't understand the reasons why we lost' Well, I suppose they were asking, but didn't get answers, yeah? And they were much more appropriate people to get the answers than we are.

There are many sources on the net discussing the possible reasons, many opinions coming from people who was directly involved (check old rec.aviation board archives for example) I don't feel we need make reposting these old sceletons here. In short, possible reasons could be proposed and expected by decision makers R&D costs, manufacturing base and flyaway costs, comparison of EMD and FSD configurations (you know how F-22 does look like and how it differs fron YF-22, now, what about how much would cost remake YF-23 to EMD? to NATF? May be, they just saw NATF-23 and took a decision momentally? Take into consideration current companies position on the market - who needs contract? Who just got a contract and have problems with performing it nice (Northrop B-2 RCS = not as advertised, MDA ATA = very bad). Lockheed needs some white job, it has almost nothing in nearest future to do. Etc, etc.