Turbine Crankshaft

Is there a possibility that when the exhaust air turns the blades of the turbine , it is slowed down , and 'transmits' pressure back to the piston ( arent you trying to invent perpetum mobila , as we all do ? ) . Forgive me for repeat myself , but would you conciser to give exhaust valve system another chance ? . Thank you.

Dany Ravikovitch

I haven't. The issue is that I can't easily switch between the straight porting and the crankcase porting on the same engine. And different engines may vary too much in performance to use as a comparison.

Tom Stanton

I completely forgot to test the thrust, maybe I should dig out my thrust stand and give it a go at somepoint.

Tom Stanton

Have you done a test to establish if porting the air into the crankcase compared with porting outside itself made a difference to efficiency ?

Cool!

Ennan

It's difficult to estimate which would work best. The turbine blade I designed is known as a reaction turbine and a water wheel type turbine is known as an impulse turbine. Both work well in different ways, however, I believe the impulse turbine can work well with just one 'stage', so you might be right. I think a tesla turbine is a tricky one as it requires high precision machining and is only efficient at very high rpm, which this engine can't achieve. Thanks!

Tom Stanton

Exactly right. I'm not entirely sure how to calculate the pressure of gas leaving the cylinder as it's very difficult to determine what volume of air is let into the cylinder per stroke, which is partly why I ran this experiment. It was a pretty crude way to test if the air flowing out the exhaust had any potential to take advantage of. Thanks

Tom Stanton

Do you consider measuring thrust?

Marek Iksiński

These tests were great man! Would be curious to see the runtime of the previous version engines (just to have a good comparison of all of them). Also, you only tested the one turbine design, I don't know much about turbines but what about another one with the fins spaced a bit further apart. Just an idea. Keep up the great work!

Might a water wheel type turbine produce a better performance? or a Tesla turbine?(though the latter might need too much precision)

Ennan

Fuel Turbines are much less efficient at sea level and overtake piston engines as you climb in altitude. But this is not burning expanding gas either and the use of simple compressed air to turn a fan blade coupled to turbo fan would at a minimum require you to spin the entire system up to speed before engaging the compressed air. If you don’t the air will simple flow around the blades without doing much work. A well sealed piston has the advantage of being pushed out of the way as the differential pressure tries to expand.

Interesting idea - I wonder if you could use the air through a small chamber like that to make the engines self starting for the car version? I think perhaps the issue is that the air is near atmospheric pressure when it leaves the exhaust. From my (limited) recollection on turbine physics when the delta pressure across the vanes is low they can't extract any work even if the volume is great. I think without calculating the dimensions of the bore and cylinder stroke, it's difficult to determine if the gas exiting the cylinder is actually at a usable delta pressure from atmospheric.

Does this mean that a true turbine-driven engine design is on the horizon? I'd like to see one and I'm curious what would be the runtime difference between the piston and turbine driven engine based on the same original source of 50 PSI of pressure.