Two other killers 1) Current solar cell production barely keeps up with the *growth* in electrical demand. 2) Current battery production is less It doesn't how expensive it is, if it's not available.

It's only cheaper if you ignore that since we *don't* have viable storage, for every watt you deploy, you *also* have to build a watt of baseload capable production (fossil-fuels, hydro, or nuclear). So, except for the fact you have to build *both* (which couldn't be *cheaper* even if the solar was *free*) totally true... not! SHENANIGANS!

Two core questions: 1) how does this compare to the efficiency of an electrically driven ducted fan? 2) what flight regimes (for example super/hypersonic) does this form of heating enable that would no be possible with electrically driven ducted fans? even if 1) isn't promising if 2) is meaningful, then it's still worth pursuing... potentially even as a SCRAM heating option for a fuel/electric hybrid

So in other words. No. You don't know anybody directly working with the issues personally, nor have you been exposed to it. I have. Close friends, organizations with whom my children have lived and worked . I recommend you do so. You might learn why the Peace Corp kids spent 8 hours a day holed up at the AIDs Orphanage and School that a US church group had established in cooperation with the village elders (and still got death threats for teaching village families to start bakeries and raise chickens).

It will change your life and your outlook.

ROI is an impossible term w.r.t. military expenditures, because you're trying to estimate costs of "the path not take" which are unknown and/or the costs of "black swan" events which are unpredictable, rare, and unknown, but potentially large. (better US military involvement might have prevented the Rwandan genocide... but that's the path not taken and a black swan to boot)

I'll give an example of the depth and breadth of the problem. There places in Africa where, when you have to bribe the police officers to avoid bogus arrest or traffic citation and don't have the correct denomination of cash.... they will make change. When the corruption is that normalized and dispersed, any addition of large scale cash infusion just gives chum to the sharks.

Do you actually know anything about African aid or have worked with people doing relief in Africa? Throwing money at kleptocracies to help the people is like squirting gasoline on a fire to prevent a building from coming down. Any foreign aid at any level barely above a person-to-person level gets subject to a 90% (or greater) skimming by those at the top, and opposed locally (by death threats, poisonings, and the like) by those in change of the local status quo. One can be fortunate to be able to find small organizations just below the radar and been able to help without the top level siphoning effect, but still face local opposition when things like "micro entrepreneurship" programs threaten the monopoly of privilege for those traditionally in power. Engaging this at the level of a nation state with the budget of the DoD... you'll create sound and fury, but like the billions poured into Haiti after the earthquake and hurricane, signify nothing.

Not only can it only produce for (at most) half the day ... the cosine law impact that product by another derating factor of pi/4... I don't know what the "solar is a cheap as ..." guys are smoking.

But what has been installed has nearly zero storage capacity. Your costing for solar + storage is way, way, off -- especially given the depreciation/depletion schedule for any current battery technology. Adding storage is nearly a 10 fold cost multiplier.