[bob1029]

> Competitors must create an aircraft that is both lightweight and powerful – lifting at least 4x its weight while flying a 5-nautical-mile circuit course.

I'd make it 50NM. 5 is way too easy to bullshit with edge case engineering. Alternatively, set a minimum payload capacity of something like 100kg.

[TeMPOraL]

Maybe "edge case engineering" is precisely what they're looking for? Get people to think about beating the rules with cheesy strategies, in hopes some of those could, with some cleverness, scale up and evolve into proper, broad-range solution - or at least become a key previously-missing component of one. But even if it can't, very narrow capabilities can still be useful too; military isn't beyond doing silly things if they offer enough tactical advantage (enough to offset extra burden on logistics, at least).

[xnx]

Giant hot air balloon for lift + 4 rotors for steering? It wouldn't be fast, but it might work [in low wind conditions].