Active Military Fighter Aircraft of the 70'ies

[Kruska]

There is also more than the bubble canopy. When you exceed Mach 2.5 your whole ac heats up. The F-104S was rated at Mach 2.2+. Note the plus sign. When the A was reengined it also was rated at 2.2+. The reengined A models speed was "Classified". The + sign was a poor statement., NASA is still flying one of those reengined fighters.

The limiting factor on the F-104 wasn't the canopy, it was the leading edges. It went so fast that the leading edge would glow a bright red. When that occurred, the fighter had to back out of it. When Nasa did a speed run on the nickel, the F-104 was circling overhead filming the run. The Nickel topped out at about Mach 2.1. That means the lightning had to be well above mach 2.4. The J79-GE-19 had a thrust of over 17,000 lbs in a fighter that weighed just over 14,000 lbs. That places the reengined F-104 at over a 1.2 to one rate. just below the F-15. There is a good reason it was chosen to train astronauts at a sustained height of 103,000 feet. It was the only bird that could do that short of the X-15. The reengined A was the lightest. But we don't list it's performance. Instead, we list the performance of the G model which was a pig in comparison and the slowest and the lowest overall performance with the exception of the payload capacity since it had more wing area added.

I don't see that the most limiting factor is the bubble canopy since the F-15 is capable of exceeding well over mach 2.8 if the pilot decides that he needs that kind of speed. Of course, V-Max means that he's going to cook an engine and have parts fall off. The Mig-31 is actually slower than the Eagle. While it may be able to hit Mach 2.8, it's going to be cooking parts. The F-15 and F-104 rewrites all the laws.

The F-104G or any other Starfighter versions, didn't have a bubble canopy, as you know.

That a bubble canopy as such places a hindrance at speeds above Mach 2.0, I am quite certain though.

What counts in a fighter, is excess power - what is left over after one overcomes drag. Excess power gives you climb, acceleration, and turning ability. Less drag = more excess power. If (as the theory went in the 1960s) the pilot was only watching his radar scope and instruments while accelerating, climbing and turning, why allow for more canopy than he needs?

IIRC - due to the Vietnam experience - realizing that dogfights would still take place and that far lower speeds represented the usual operation parameters, a better pilot sight issue, bubble canopies came back into the discussion.

Add to this bird strikes and windscreen heating issues. The Book ("Phantom Over Vietnam" has an anecdote of the windscreen heat warning alarm going off during a high Mach flight test, & causing a mandatory abort). Therefore modern materials and fabrication methods where needed to overcome these issues, (only available from the 70'ies onward). Thus the small canopies of the Phantom, Lightning, Mirage III, F-104G, F-106, MiG-21, etc. made sense at the time. The same "material" related issue applies to the heating up of the F-104G's leading edges as you had mentioned.

As for Mach 2.2 or 2.2+ on the F-104G - I don't think so. (Independent of some NASA non-combat related F-104 flight tests).

According to my father and other Luftwaffe F-104G pilots - the highest speed recorded with a 100% clean configuration (aka - half filled tanks, no missiles, no drop tanks) was at around 2450km/h - which equals to Mach 2.1

As for the F-104G's that were build in Germany and some given to NASA (3) e.g. N826NA (German SN KG200) - those had the J79-MTU-J1K, was licensed built and an improved version of the GE-11A Turbojet - and was rated at 15,800 lbf.

AFAIK, only the much later build, (70'ies onward) essentially a J79-GE-17, co-developed by Alfa Romeo for the Aeritalia F-104S, was rated at 17,900 lb (79.6 kN) and was a pure interceptor.

The J79-GE-15 or J79-GE-17 - only came into the picture with the e.g. F-4's and the Kfir C-1.
BTW, where does your information derive from, that an F-15 could achieve Mach 2.8 and even more?