Interesting. In general though I wonder why it is such a struggle for the F-35 to fly fast. You would think the combination of one of the most powerful jet fighter engines, along with a very clean aerodynamic layout would easily enable it to reach M2, and supercruise for prolonged periods. What am I missing here? An F-16 with weaker engine, wings with hardpoints still can fly faster...
The F-16 doesn't fly faster, at least when equipped with as close to a load as the F-35 that it can.
- The F-35 is rated and has been tested at M1.6 with two AIM-120s and two 2,000 lb weapons internal as well as full fuel load as possible, 18,000 lbs. That loadout includes an exceptional internal jammer, targeting pod etc.
- The F-16 Blk 50/52 if equipped with a loadout of 2 AIM-120s, 2 600 gallon fuel tanks, tgt pod, nav pod, 2 GBU-10s has a drag index of 185 with a total fuel load of 15000 lbs.
- 600 Gal tanks + pylon have a DI of 30 each so 60, two wingtip AIM-120s are free, two GBU-10s are 30 each so 60 total, Tgt pod is 19 + pylon is 34, Nav pod is 32 with pylon.
Using the HAF F-16 Flight Manual Supplemental https://info.publicintelligence.net/HAF ... lement.pdf
that gives an F-16 max top speed of between Mach 1 and Mach 1.2 at around 36 kft. Essentially the F-16 at that loadout struggles to break M1. Yes a clean F-16 will fly faster, the above HAF flight manual says an F-16 with a drag index of 100 will hit M1.6 at approx 38 kft but how far and what load does that provide the F-16? Take away the fuel tanks or the tgt/nav pod and the F-16 either struggles to hit the target when it arrives or can't hit the target because it doesn't have the fuel or needs additional tanking. Looking again at the HAF F-16 Flight Manual we see that the top speeds of the aircraft are in that 34-40 kft range based on drag and weight. Even with a drag index of zero the F-16 top speed is reached at 38 kft and degrades below that the higher it goes. A lighter load will favour the lighter aircraft and so when you put a light A2A load, say four AIM-120s similar to internal F-35 carriage, on an F-16 it looks a lot better but still lacks fuel, sensors and ECM.
What we know is more likely is that the F-35 top speed is a limit that likely arrives from either stealth material degradation beyond that speed or a limitation of the diverterless inlet (if the inlet then the trade off of lower maintenance and improved RCS is likely worth it, if the stealth material then again likely worth it). The other side of this is that M1.6 is an achievable top speed for the F-35, multiple test pilots have stated this including the recent Fighter Pilot Podcast episode on the aircraft. So in that context you see that the airframe and the big engine actually provide the F-35 with some very impressive real world and operational numbers.
The F-35 almost certainly does supercruise, it is pretty clear it can cruise at approx M1.2 for an extended period of time per aircrew comments. Compared to the F-22 which can supercruise at M1.8 but has almost twice the dry thrust on a slightly larger and heavier aircraft with the same or less fuel load (F-35C has a greater internal fuel load than F-22).
The issue for the Bee and Cee really looks to be about drag and weight. Given the F-16 numbers above it is pretty clear the extremely high altitude
stipulation is an edge case and is better mitigated through tactics, techniques and procedures than by requiring expensive materials and antennas that can withstand the extreme burner use required to achieve that zone.