I see youtube videos of all the small jet engines, about the size of a milk jug.
I doubt the jet could take the centripedal forces of being mounted on the ends of rotors, but here is some othe ideas
1. Mount on mast and divert exhaust through pin hole venturis on back of blades for jump take off.
2. Divert exhaust gas and thrust at a "turbine" like a tourqe converter that is mounted under blade hub.
Would these ideas work for jump take offs like the rotordyne did?
Go ahead and feel free to shoot holes in my ideas...I'll never build one.

Jet thrust on the tips Worked with a lot of helicopters over the years

I even mounted a small JFS 100 jet engine on a Brock KB 2 . looked great -I was in Corona and he lived in the Riverside area...

Be damned when it fell off his trailer on the freeway .... Stupid straps....

You want to talk about straps!!!
My son had an accident one day because of harbor freight cheap chinese straps that nearly cost him his life!
Still has a small amount of permanent brain Damge from it.
Worst day of my life.

On another note, what were you doing with the jet? Propulsion of blades or forward thrust for rig?

A jet powered gyro all done. Mounted plumbed tested and ready for flight at his home airport....

on the freeway a strap split and it tumbled at 75... engine mounted for thrust behind the seat.

I had a China crap cut off wheel explode and miss my nutz and put holes in my hangar door..... behind me

Did someone say 'tip jets'?

Well yea Muz...but I am thinking of a mod to a Sportcopter, not a heavy lifter!
If these new jets could take the spinni g you could just mount them on the tips, but the extra weight might sacrifice handling.

look up Hiller Hornet - Ram jet power

I am familiar with the Hiller Hornet. Would Mini-Turbine jets on the ends of the blades not be better then ram jets?
For that matter, what if you mounted the jets inboard of the rotors "driven range" instead of at the tips?
Is this at all workable?

Yes and yes

Not what you are asking about ..... but there is a video where someone took a basic gyro frame and rotor ... increased blade pitch a couple of degrees , fed 93% hydrogen peroxide to blade tips .... where there was a silver screen (catalyst) which turned the H2O2 into steam pressure .

It flew (hovered around) ... but had no collective pitch ... flew surprisingly well as a "helicopter" using a Bensen rotor

Very simple and tip jets were very small and slender.

Also Army experimented with an early Sikorsky using H2O2 auxiliary power at the tips for max power takeoffs
.

.

I have watched model rocket guys insert a replaceable cartridge ... ignite it ... and that rocket goes so fast and and high the eyes can hardly keep up to it.

Couple of those in tips of a gyro rotor might pre-rotate to 200 rpm in about 15 seconds .... would be easy to test on a ground-based mock rotor stand

.

Yeah, that was merely 'attempted humor' haha

Didn't the Fairy Rotordyne use tip jets too?

Hi,
here is a really encouraging video :

https://youtu.be/hrgdcmYGDQ0

even if it is really complicated to do the same it shows that a powerful pre-rotator makes many astonishing things possible

In montelimar, we have the strongests regular french north wind, Kamal my mate worked a lot on his pre-rotoator pushing it up to 320 rpm using a magni flex shaft system making it possible to pre-rotate pulling the stick

with a 50 km/h head wind, workingout his technique a lot he manages to make really clean zero roll takes off,

when I say clean I mean not like the guy on the video who climb steeply in the dead zone immediatelly after take-off

kamal precisely doses rotor angle of attack so that he takes off 3 wheel at the same time, and then accelerates at 1 meter over the ground until he reaches Vx .

the real problem he has is that he can't ajust the propeller finely power because he needs power for the pre-rotator and say that if the powerful electric rotator could work with an automatic acceleration he could ajust the throttle and stick to make even better takes off.

the problem is that this rotator doest not work for the moment ... hahaha but it will

it is works one day I really would like to try to install a sensor on the front wheel that would cut the pre-rotator power during the ground acceleration when the wheel lifts ..