The line aboutthe fuel being too hot to be used as coolant is crap. They used it on the SR71 in the 60s. And the SR generated way more heat than this plane.
Here's a writeup that talks about the issue:
http://foxtrotalpha.jalopnik.com/the-f-35-cant-run-on-warm-gas-from-a-fuel-truck-that-sa-1668120726The SR-71 is a completely different animal. First off, it is designed from the ground up to withstand much higher temperatures (turns out that going Mach 3+ generates a LOT of heat from friction from air being forced over the aircraft surfaces). Also, JP7 fuel has a significantly higher flash point than JP-8 does, again with the heat envelope that the SR-71 operates within in mind. Over 90% of the SR-71 uses titanium composites, so that the wings and such don't simply melt away or deform at the higher temps from friction at Mach 3+.
In fact, the SR-71 was well known for leaking fuel like a sieve when sitting on the runway. Once the flight surfaces expanded from in-flight friction and such increasing the surface temp of the craft, then the leaks would seal up, which is why SR-71's generally refueled once they were underway, to replace all of the fuel left on the ground back at base, as well as to top off the tanks (SR-71's generally began their missions with just enough fuel to take off and make it to the tanker, so they wouldn't waste as much fuel on the ground). I've attached a pic showing a fuel puddle accumulating underneath an SR-71 during mission prep.
The F-35 isn't capable or expected to operate in those environs. She tops out at about Mach 1.57, using published specs (1,199 MPH top speed)
Finally, as noted in the article above, the F-35 was designed to use it's fuel as a heat sink for it's avionics and such. This was done partially to reduce the weight of the craft. Sure, they could have handled shunting heat in a different manner, but that likely would have added to the weight of the craft, hence reducing it's potential payload capacity.
The Air Force quotes I've read on this issue mention that once the F-35 is flying, this is not an issue. Which makes sense because the craft is in motion at that point. The potential issue arises during takeoff operations, at which point the craft isn't able to shed heat as easily (air isn't passing over the flight surfaces as rapidly, or much at all at all during taxi operations). The Air Force also claims that this won't affect mission readiness, but of course they aren't going to openly admit that their new baby has a significant flaw in it's design...
In short, I'm not surprised that the whiz kids at Lockheed designed the heat envelope for the F-35 so tightly. One only has to look at current engineering trends to see how much less 'overengineering' is done these days. Gotta make room for all of the other 'features' (in aircraft as well as in automobiles) ya know... The SR-71 was borne from those 'overengineering' days, as was the B-52...
I'm sure this 'fuel issue' will be worked out in future variants/blocks, of course. That's generally how it's done. Identify the problems in the 'A' model, fix it in the next one. Of course, in the F-35's case, it'll start with D/E/F (A is conventional, B is VSTOL, and C is the Carrier variant). The articles I've read so far refer to the 'A' variant, dunno how the B's and C's are faring with this issue.
I've also attached a pic of an M-21 (SR-71 variant) with a drone strapped on, just because...
