Similar principle to this one:

https://en.wikipedia.org/wiki/NHI_H-3_Kolibrie

Powered by ramjets at the rotor tips. Very loud little machine, they used to have one on display at the Dutch aircraft museum Aviodrome but the last time I was there it was no longer there.

Indeed, and taken to new heights of obnoxiousness by the British: https://en.wikipedia.org/wiki/Fairey_Rotodyne

The tip-jet design was first developed by the philosopher Ludwig Wittgenstein. Back when aeronautics was the hot technology.

https://en.wikipedia.org/wiki/Tip_jet#History

https://royalsocietypublishing.org/doi/full/10.1098/rsnr.200...

The photo in that Wikipedia article...

I can’t stop seeing it as a computer rendered image.

Why does it look weird like that? To me?

Lack of shadows, geometric shapes in brilliant colours (some of which look bidimensional, like the red vertical strip on the windshield), a hint of triangular patterns at the top right. It definitely gives that feeling.

The reasons as already pointed out and the lack of shadows make it look a little odd.

I don't know but it looks like the perspective is very flat. I.e. it looks like taken with a long lens. (Telephoto.)

Some computer renditions are also very flat? In any case, the human eye is said to be like 30 to 60mm lens equivalent.

That name is derived from "colibri": hummingbird.

I was reading that article and thought "that sounds cool" and got to the bit where it mentions "hydrogen peroxide fuel" and changed my view to "that sounds terrifying"...

I'm not sure how dangerous that is, but it did give them an engine with fewer moving parts:

"It is lifted by a thin, 17-foot rotor blade that whirls just above the pilot's head under the power of hydrogen peroxide fuel broken down by catalytic action into steam that is ejected at high speed from the rotor tips."

"Ultrasimple, it has no pistons, no electrical system, no lubrication or cooling system, no clutch, transmission or starter."

They are presumably using high test peroxide - which is interesting stuff:

https://en.wikipedia.org/wiki/High-test_peroxide

Not sure I would want to be effectively wearing a tank of the stuff.

> Not sure I would want to be effectively wearing a tank of the stuff.

https://en.wikipedia.org/wiki/Bell_Rocket_Belt

From what I understand, most rocket belt designs continue to use such a system...

The latest design, with a better catalyst matrix, works with 50% H2O2. That matters because you can buy it, and don't need to make it yourself on the spot like the 70% solution.

I have not succeeded in finding out whether the rocket version is loud like the ramjet one.

This is impressive engineering

"Ultrasimple, it has no pistons, no electrical system, no lubrication or cooling system, no clutch, transmission or starter"

for super small kit helicopters of today, with typical combustion engine, see: http://www.mosquito-helicopter.info/Mosquito_Options_Air.htm...

>> A followup story in the Nov. 5, 1957, Los Angeles Times reported that Whitehead suffered a broken leg and other injuries "after the Buck Rogers-type craft went out of control" and fell about 50 feet.

Perhaps not for civilian use, then.