Tip-Jets - The Most Kerbal Helicopters To Ever Actually Lift Humans - YouTube
Why are tip jet helicopters so rare, even though it doesn't seem very complex and would work fine with current engines, like turbines or any kind of compressor? - Quora
What Are Tip Jet Helicopters? | Flite Test
Tip-jet UAV Unveiled by Unmanned Systems | Defense News: Aviation International News