This is certainly one way to put a pulse jet to use lmao

[wannabebuilderuk]

youtu.be/Q9-weExLUA8

Would love to know what the forces on the wire is at top speed..

[racket]

And another use www.youtube.com/watch?v=uqMn0A2aUdo

[wannabebuilderuk]

Jesus john, you're practically the mechanical aussie version of tesla lmao. How did the prop thust compare to the pulse jet?

[racket]

Prop thrust was poor , I eventually came to the conclusion that PJ thrust is a combination of "reaction thrust" from the expelled gases plus "pressure thrust" from the differences in surface area of the combustion chamber , the front surface being greater in area than the rear surface which has a "hole" where the exhaust pipe is, so when the "explosion" happens theres more force ( thrust) put on the front than the rear.

Theres a "Build Thread" over on the PJ Site www.pulse-jets.com/phpbb3/viewtopic.php?f=2&t=2349&hilit=turboprop+pj

The PJ experiment was a distraction from turbines for a short while after getting the TV84 turbine bike sorted .

Without the prop being fitted, the freepower was able to be spun up to >20,000 rpm unloaded , it didn't make much difference whether the connecting sleeve between PJ and freepower duct was in place or not , the PJ "breathed" back through the freepower .

If it was done again I'd recommend doing things slightly differently , having the freepower shaft at right angles to the PJ pipe and use a "scroll" arrangement like I did with my 12/118 freepower stage to get a "better" alignment .

I ran the PJ on both liquid propane and/or petrol , it was a strange beast that took a while to get sorted but in the end starting was very simple and quick .

Cheers
John

[racket]

And another vid I just found youtu.be/KVQavn_o_lE

[slittlewing]

That’s quite a fascinating experiment John!! I would never have thought of or considered adding a free power to a PJ haha. Great work!!

[racket]

LOL..........I thought I might as well try something "different" ;-)

PJs are strange beasts, and there are things that probably could be done to improve their ability to more effectively power a freepower , longer pipework to reduce "frequency" would be a start , turning it from a high revving short stroke motor to a long stroke diesel .

Also maybe fitting the freepower at mid point of the engine closer to the combustion chamber .

But I doubt they'd ever compete with a standard gas turbine engine , but the bragging rights would be better :-)

Cheers
John

[racket]

Hi Guys

Its a wet miserable day with nothing to do, so heres some more pics of the PJ setup , its interesting going through old pics





And the sliding sleeve that joined the PJ to the freepower ducting to make the PJ breath back through the turb wheel

[racket]

And a few more

Sliding sleeve


Fuel pump



Gauges and switches for the various pumps , ignition etc



Starting air cylinder ( WW2 aircraft oxygen cylinder) with small 12v air comp to fill it

[racket]

Front end with "horns" that were fitted with 2 stroke piston engine "plastic" reed valves and their mounts





fuse board and some plumbing



Expansion witness marks , the PJ was mounted at the front and was allowed to expand rearwards , sliding through the "saddle" , ............lotsa expansion , it got kinda hot

[racket]

Inlet to the freepower ducting, because theres no pressure ratio across the freepower the ducting needed to maintain a constant flow area as the gases were turned in the "NGV" , the NGV "throats" were the same area as the exhaust pipe, actually a tad bigger to account for any losses in the turning process , I only provided a modest turning angle of ~60 degrees if I remember correctly , this could be increased to ~75 degrees I feel without too much problem



"Bump bearing" for the long power shaft



Fuel valving was messy due to trying to combine petrol and propane



Turbine blades took a hammering from the extreme temperatures and pulsing , they were only segments of stainless tubing with minimal bend/deflection , again another area where power could be improved by greater deflection





And finally the poor old shaft tunnel and bearings , the heat got to them badly , it looks like I added air cooling , but that wasn't enough





Cheers
John

[racket]

Hi Guys

Some pics of the final disassembly

[wannabebuilderuk]

Man john that's rather impressive, what is just a little fool around/test to you is practically a project that accompanies a scientific paper for us in my opinion lmao. You have some great knowledge and skill so I tip my hat to you.

[gidge348]

May 19, 2020 4:11:37 GMT -5 wannabebuilderuk said:

youtu.be/Q9-weExLUA8

Would love to know what the forces on the wire is at top speed..

Approximately 4.24 kg spread over 2 wires.