Many years ago I built the "Schreckling FD3 64" miniature gas turbine, this picture is of not mine but is the same design and in it there was a shrouded centripetal compressor impeller that was made out of R/C aircraft grade plywood reinforced with carbon fiber "twine" and crazy glue. It was not very efficient but the design would work (rated at 75000 RPM's) if built according to the prints and many R/C aircraft have been flown with them, more so in Europe than in NA.
I have been researching newer design which all use the non-shrouded impellers out of turbo chargers for the compressor and was wondering if an idea that I had for a fabricated impeller would work. I don't have a CNC mill or lost wax investment casting equipment so those methods are out hence the "idea".
If the center, curved, portion is machined on a lathe, I have the specs and dimensions for the impeller in question and slot's where cut in it for the blades to be epoxied in place (this in it self would not hold against the forces involved and it would be torn apart) and then reinforced in the same manner as the plywood impeller of the earlier version to hold the blades onto the main part of the impeller, would this hold together.
In the earlier version it worked because of the carbon fiber/crazy glue reinforcing "rings", which will not expand with the centripetal force (fiberglass and even Kevlar will expand and cause a failure), that where put into the impeller. If these where put on the fabed impeller in the same manner it would seem to me to be doable if the engine was held to a similar rating. The newer designs with turbo impeller and inconell turbine rotors can run up to as much as 140000 RPM's and 2 or 3 times as much thrust but I'm not as interest in that as much as being able to produce an engine with all the parts, less the bearings, made by me.
Yes I could buy an impeller but where would the fun be in that. Plus the difficulty in finding the one that you need, suppliers for these in the home built turbine area have a habit of disappearing leaving a design without a source of parts.
If there are any injunears out there, would it work??? ??? ???
I have been researching newer design which all use the non-shrouded impellers out of turbo chargers for the compressor and was wondering if an idea that I had for a fabricated impeller would work. I don't have a CNC mill or lost wax investment casting equipment so those methods are out hence the "idea".
If the center, curved, portion is machined on a lathe, I have the specs and dimensions for the impeller in question and slot's where cut in it for the blades to be epoxied in place (this in it self would not hold against the forces involved and it would be torn apart) and then reinforced in the same manner as the plywood impeller of the earlier version to hold the blades onto the main part of the impeller, would this hold together.
In the earlier version it worked because of the carbon fiber/crazy glue reinforcing "rings", which will not expand with the centripetal force (fiberglass and even Kevlar will expand and cause a failure), that where put into the impeller. If these where put on the fabed impeller in the same manner it would seem to me to be doable if the engine was held to a similar rating. The newer designs with turbo impeller and inconell turbine rotors can run up to as much as 140000 RPM's and 2 or 3 times as much thrust but I'm not as interest in that as much as being able to produce an engine with all the parts, less the bearings, made by me.
Yes I could buy an impeller but where would the fun be in that. Plus the difficulty in finding the one that you need, suppliers for these in the home built turbine area have a habit of disappearing leaving a design without a source of parts.
If there are any injunears out there, would it work??? ??? ???
