I still believe it's possible - for example by having all the blades enclosed in a ring you can avoid gas escaping 'round' the blade. And with metal 3d printer

I still believe it's possible - for example by having all the blades enclosed in a ring you can avoid gas escaping 'round' the blade. And with metal 3d printers rapidly falling in price, I think it will get within the scope of university students to prototype soonish.