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.
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 .
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 :-)
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
Post by wannabebuilderuk on May 21, 2020 16:32:54 GMT -5
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.