Northrop YF-17 WHIF

[KJ_Lesnick]

I was thinking, what if Northrop decided to make a dedicated LWF like GD did, instead of an F-5 derivative they could use for exports that would double as the LWF, what would it have looked like?  Would it have still had F-5 characteristics?

Could they have pursued a dedicated LWF *and* a modified F-5, like an F-20-like design (for export purposes)?

[elmayerle]

You mean in addition to the YF-17 or in competition to it?  If you're talking something closer to an improved F-5 in size/performance, some of the studied F-20 developments would qualify; for that matter, the study Northrop did on F-20/Lavi hybrids to reduce costs produced a couple interesting concepts.  If you're talking about something directly competitiive with the YF-16/YF-17, I could see them perhaps flying one prototype of the P.610 design which would've had a single large engine, ala' the YF-16, rather than two smaller ones as the developed  P.620/YF-17 used.  There was also a proposal made for a "big wing" F-5 derivative with room for an extra hardpoint under each wing and a wingloading that was back down to that of the F-5A/B for a two-seat aircraft that would've been powered by two afterburning J97s.  Since this didn't come from the PD/AD office, it suffered from the NIH syndrome and never really was considered too much farther.  There was also an attempt to get a couple engine companies to develop a suitable modern turbofan replacement fot he J86 but they wanted too much up front (as I understand it) which is a shame because the new engines, in dry form, likely could've been used to re-engine a lot of 20-series Learjets and bring them into noise compliance.

[KJ_Lesnick]

Dear Evan,

Well the idea I was thinking of would be if the YF-17 was designed instead of being a LWF contender and export-fighter, as just a dedicated LWF design like how General Dynamics designed their YF-16.  Either just that, just by itself (To stand a better chance in the LWF program) or in addition to a dedicated LWF, Northrop would also design a new export fighter to replace the F-5 and F-104, I'm thinking like the F-20 or something. 

Did Northrop have the monetary resources to do that?


KJ Lesnick

[elmayerle]

Well the idea I was thinking of would be if the YF-17 was designed instead of being a LWF contender and export-fighter, as just a dedicated LWF design like how General Dynamics designed their YF-16.  Either just that, just by itself (To stand a better chance in the LWF program) or in addition to a dedicated LWF, Northrop would also design a new export fighter to replace the F-5 and F-104, I'm thinking like the F-20 or something. 

Did Northrop have the monetary resources to do that?

I'm not entirely certain that they did at that point in time.  If memory serves me correctly, botht eh P.610 and P.620 were proposed (both being derivatives of the P.600 which derived from the original P.530) to the USAF in the LWF competition and the USAF preferred the P.620 as a basis for the YF-17.  Mind you, I suspect part of that may have been because it was the only twin-engined proposal offered and they genuinely wanted to evaluate as many variables as possible.  As I said, evolved versions of the F-5, other than what became the F-5G/F-20 were proposed and evaluated but none eventuated.  I still say the F-5G/Lavi hybrids were some very attractive aircraft and likely would've made the Lavi an affordable design while dealing with the high wing loading that afflicted the as-built F-20s (that's why three were lost to g-loc, the turn rate to maintain a level turn was a mite too much with that wing loading - or so I understand it).  There were plans for a larger wing later, but the buitl prototypes shared a wing with the F-5E/F and that shared the same basic area as the wing of the F-5A/B which was a much lighter aircraft.

[KJ_Lesnick]

Dear Evan,

I'm not entirely certain that they did at that point in time.

But they did have the means to build one or the other right?  Could they have built a more dedicated LWF if they wanted?  Did they have the ability to build that shark-nose during the time of the LWF competition (or one that could accommodate a radar like the F-20 did) reasonably speaking?


KJ Lesnick

[elmayerle]

I'm not sure Northrop would've had the knowledge during the LWF competition to do the shark nose (a lot of that aerodynamics was developed later).  They certainly had the production capacity but I'm not sure they had the knowledge base then.

[KJ_Lesnick]

Evan,

Wasn't the F-5E created in 1971?

[elmayerle]

Wasn't the F-5E created in 1971?

Yes, but the original configuration had the same nose as the F-5A had.  The main difference was more potent engines, enlarged LERX, and equpment upgrades.  The shark nose and the modified LERX shape (In plan view) didn't come along until the 1980s.

[KJ_Lesnick]

Dear Evan,

I did not know that.  I thought the F-5E from the beginning had that shark-nose. 

What knowledge base led to the creation of the shark-nose?  I've been told Northrop was an expert in the field of spin-resistance and vortex formation off the nose at high alphas even when they created the T-38 and F-5's.


KJ

[elmayerle]

I believe the knowledge base that created the shark nose was a development of the reserch and theorizing from the LERX development fo rthe Cobra/Hornet development line.  There wer a group of aerodynamicists who took the control of vortexes further to produce the shark nose.

[KJ_Lesnick]

Evan,

I believe the knowledge base that created the shark nose was a development of the reserch and theorizing from the LERX development fo rthe Cobra/Hornet development line.  There wer a group of aerodynamicists who took the control of vortexes further to produce the shark nose.

Now that's some useful information!

If Northrop was designing a dedicated LWF instead of a LWF that could double as an export-fighter, do you think the additional dedication and research could have lead to such a development earlier?  I mean the F-16 had kind of a flat nose (although I'm not sure about the YF-16). 


BTW:  Do you think that Northrop would have had a chance of winning the competition even if it's design was better in every way over the General-Dynamics design?  I remember hearing that GD Fort-Worth plant was highly valued by the government and if General Dynamics lost the competition (I remember reading that they were putting everything behind the LWF, dunno if that's true or not) the plant would end up getting closed.  You think that's true?  Or you think the winner would have simply got the plant?


KJ Lesnick

[elmayerle]

The F-16 nose was essentially the lowest-drag nose they could fit that would accomodate the necessary radar.  For aerodynamic purposes, it wa squashed for a round cross-section to an oval one.  Have you ever seen the imockup for putting an An/APG-65 from the F-18 into the F-16?  it definitely has some "interesting" contours.  I don't know that Northrop would've necessarily gotten to taht development that much earlier (look at the radomes on the various Cobra designs); it  was very much an iterative process for developing the concepts.

[KJ_Lesnick]

Evan,

The F-16 nose was essentially the lowest-drag nose they could fit that would accomodate the necessary radar.

I did not know the YF-16 was designed around possessing a radar.  Was the YF-16's nose rounder?

For aerodynamic purposes, it wa squashed for a round cross-section to an oval one.

Fascinating...

Have you ever seen the imockup for putting an An/APG-65 from the F-18 into the F-16?

I thought the radar used on the F-16A was an APG-66?  Regardless I did not see the mockups.

it definitely has some "interesting" contours.  I don't know that Northrop would've necessarily gotten to taht development that much earlier (look at the radomes on the various Cobra designs); it  was very much an iterative process for developing the concepts.

When you say iterative you mean in response to shortcomings with the original design right?


KJ Lesnick

[elmayerle]

The YF-16 did not have a radar, but adding one was one of the requirements for the production F-16.  This converted what was essentially a conical nose into the longer radome shape seen on all production F-16s.

When the AN/APG-65 was announced for the F-18, GD did a mockup to see if one could be fitted to the F-16 in place of the AN/APG-66; the resulting design was decidedly Durante-esque.

Not necessarily for "defects" so much as "lessons learned during the design process".  A good design generally goes through several iterations before you get the final product (look at the evolution of the NAA Mustang - and not just the obvious changes; the redesign for the P-51B also incorporated some significant redesign that greatly improved producability while reducing susceptibility to damage for the cooling system).

[KJ_Lesnick]

Evan,

The YF-16 did not have a radar, but adding one was one of the requirements for the production F-16.  This converted what was essentially a conical nose into the longer radome shape seen on all production F-16s.

So it was lengthened *and* flattened?

When the AN/APG-65 was announced for the F-18, GD did a mockup to see if one could be fitted to the F-16 in place of the AN/APG-66; the resulting design was decidedly Durante-esque.

I assume the APG-65 was superior to the APG-66?

Not necessarily for "defects" so much as "lessons learned during the design process".  A good design generally goes through several iterations before you get the final product (look at the evolution of the NAA Mustang - and not just the obvious changes; the redesign for the P-51B also incorporated some significant redesign that greatly improved producability while reducing susceptibility to damage for the cooling system).

Understood.  I was thinking about the T-38A and F-5A, and I looked at several pictures of them using Google image-search.  Now I'm not sure if they revised the T-38's nose like the later F-5's, but it would seem at least in some pictures that the T-38A's nose is a bit wider than it's depth.  Am I wrong?


KJ Lesnick