Northrop goes early with 1-engined F-5?

[Lascaris]

Fun fact I learned from another thread: if you want an afterburner for the J52, ask SAAB. The Viggen engine was a civilian J52 developped for airliners, to which they added an afterburner (that's how I remember the whole story, I could be wrong).

I'm still rooting for Sud Aviation F-5s salvaging the M45 out of the AFVG boondoggle (from Liébert & Buyck stupendous Mirage F1 monography).

View attachment 765941

General Electric J85 - Wikipedia

en.wikipedia.org

One can see that one M45G1 has more thrust (5400 kg) than a F-5E pair of J85 (4500 kg).

Unconnected but I always wondered how exactly AFVG was supposed to work as a fighter with such anemic engines.

 

[CV12Hornet]

Fun fact I learned from another thread: if you want an afterburner for the J52, ask SAAB. The Viggen engine was a civilian J52 developped for airliners, to which they added an afterburner (that's how I remember the whole story, I could be wrong).

I'm still rooting for Sud Aviation F-5s salvaging the M45 out of the AFVG boondoggle (from Liébert & Buyck stupendous Mirage F1 monography).

View attachment 765941

General Electric J85 - Wikipedia

en.wikipedia.org

One can see that one M45G1 has more thrust (5400 kg) than a F-5E pair of J85 (4500 kg).

It's a little more complicated than that. For one, the civil engine, the JT8D, was a significant modification of the J52 in its own right, only slightly larger than the J52 but over 1000 lbs heavier, and a bypass jet, to boot. And then the RM8 was practically an entire redesign - the engine had to be made much more thermally resistant for supersonic airflow, something neither the J52 nor the JT8D had to deal with. They also swapped vendors for the fuel control system and enhanced the thrust reversers. The result is an engine significantly larger than the JT8D, in a similar class to the J75.

Okay, so it's a lot more complicated than just "add an afterburner".

 

[Archibald]

Unconnected but I always wondered how exactly AFVG was supposed to work as a fighter with such anemic engines.

Didn't seems to have bothered French Jaguars, which (unlike their british siblings) stuck with anemic Adour Mk.102 until the end of their lives, and flew combat missions in dusty hot Chad with AS-37 Martel.
(I know, Jaguar is not an interceptor. Albeit A2G is heavy so power is necessary.)

 

[Archibald]

And now, the justification for an hypothetical M45G1, french, single-engine F-5... the answer is : ECAT.

While the anglo-french failed to meet the ECAT basic requirement with the Jaguar (too big and expensive for a supersonic trainer, attack had overrun training); Northrop N-156 evenly fit the ECAT bill: N-156T also called T-38, and N-156F best known as F-5A.

Note that while Jaguar is far better for attack than any F-5, it is that very strike role that carried it away from the original "supersonic trainer with limited attack". My understanding is that the Jaguar attack role grew from the british side (MRI) in relation with all the TSR2 / AFVG / F-111K miseries.

We can imagine a scenario where circa 1964 Sud Aviation sneaks between Breguet, Dassault and the British and makes a bold counter-proposal: licence-build Northrop N-156s for ECAT.
But the french government balks at the J85s, so Sud Aviation proposes the AFVG's M45G1 instead. No more need for the M45G / Adour duo, as the M45G do both anglo-french aircraft: ECAT and AFVG !

 

[Scott Kenny]

And now, the justification for an hypothetical M45G1, french, single-engine F-5... the answer is : ECAT.

While the anglo-french failed to meet the ECAT basic requirement with the Jaguar (too big and expensive for a supersonic trainer, attack had overrun training); Northrop N-156 evenly fit the ECAT bill: N-156T also called T-38, and N-156F best known as F-5A.

Note that while Jaguar is far better for attack than any F-5, it is that very strike role that carried it away from the original "supersonic trainer with limited attack". My understanding is that the Jaguar attack role grew from the british side (MRI) in relation with all the TSR2 / AFVG / F-111K miseries.

We can imagine a scenario where circa 1964 Sud Aviation sneaks between Breguet, Dassault and the British and makes a bold counter-proposal: licence-build Northrop N-156s for ECAT.
But the french government balks at the J85s, so Sud Aviation proposes the AFVG's M45G1 instead. No more need for the M45G / Adour duo, as the M45G do both anglo-french aircraft: ECAT and AFVG !

That really makes decent sense logistically, too... gets you a bigger order of engines, so you get more spare parts and can swipe spares from the trainers to keep the AFVGs up if you have to.

 

[Archibald]

Just thought about a fun fact... while the M45G1 sucked on AFVG, making it underpowered; on a F-5A airframe it no longer sucks, because it provides one ton thrust more than the pair of J85s. Plus the far better sfc of an advanced turbofan ! This also applies to the Mirage III & Mirage V: while M45G1 thrust is a bit lower than an Atar 9C, the weight and sfc gains should be pretty huge.

 

[Hood]

Didn't seems to have bothered French Jaguars, which (unlike their british siblings) stuck with anemic Adour Mk.102 until the end of their lives, and flew combat missions in dusty hot Chad with AS-37 Martel.

This still mystifies me.
RAF pilots continually screamed for more power right until the end while the French pilots just got on with it.
Maybe the RAF boys were all frustrated boy racers?

 

[Archibald]

This still mystifies me.

Me too. Frech pilots joked "le Jaguar décolle seulement car la Terre est ronde" (Jaguar takeoff thanks to Earth curvature). Even more bizarre, the Jaguar M, too, for obvious reasons screamed for more power, and pioneered modular reheats for the AdA Jaguars. But nobody seemed to have ever thought "those british Adour Mk.104 may help". Neither Turboméca nor the AdA.
Probably because the Jaguar was an "orphan" lost among scores of Mirages. My bet is on this: Dassault hated it, as for the AdA they had many other ground pounders: Mirage IIIE, Mirage VF (a gift from Israel in 1972), Mirage F1CT, Mirage 2000D...