This is my air driven prototype micro turboprop engine that i made using methods from my tiny model jet engine. It has a free turbine wheel which means, air is fed in the inlet, passes the guide vanes and hits the turbine wheel which in turn spins the shaft that is connected to. Then, with a 12:1 gear ratio the power is transmitted to to a propeller (108mm x 68mm). For its size i think it`s quite powerful, but i don`t know if it could fly a small rc plane.
Maybe if i could increase the air pressure for example at 50 or 60 psi it would probably be able to lift a micro rc plane. The reason i didn`t do it was due to the fact that i wasn`t sure if the bearings could withstand that much stress ...Also, this engine could be used as a micro turboshaft engine for a micro sized hepicopter, as it has really good torque. The only limiting factor i think is the air supply. It`s difficult to make a reliable micro air tank that could fit to a micro sized aircraft, that is strong enough to withstand high pressure to power the engine for 3 or more minutes, and small enough to fit the aircraft.
As you can see in the video the turbine wheel was spinning at 144,000 rpm which is pretty high and if i attempt to grab the shaft with my hand (if i remove the propeller of course) it`s really hard to stop it which means it has some good torque. I will definitely connect it to an electric motor generator to see what kind of power it can produce. Also i will make an assemby video of this engine to show you how does it look like inside and out.
Micro Turboprop Engine:
Overall length: 42mm
Diameter: 11mm
Shaft: stainless steel 2mm dia.
Turbine wheel: Axial flow 8.5mm dia, made from stainless steel sheet
Ball bearings: High speed hybrid ceramic bearings (2mmx5mmx2.5mm)
This technique of 3D printing the wing ribs to hold a true aerofoil shape worked out super well! Combined with foam sheets, packing tape and the lightweight wooden spar, it performs amazingly well!
