February 26, 2024
Description
This is my latest fully 3D-printed compressor for a hybrid electric jet engine. It has a high speed impeller that compresses air to just above 4 PSI of static pressure, and maintains up to 3.5 PSI at very high flow rates. This is ideal for small to medium afterburning jet engines as the electrically driven compressor bypasses the need of a turbine completely. With the right motor, this draws A LOT of power (>2500w) and heats up the air significantly. Therefore, high temperature filaments are recommended as the pressure it generates may inflate the diffuser like a balloon if it is printed in PLA. This comes with an adapter that fits to a 75mm stainless bottle, which can easily be modified into an effective afterburner for this compressor. I used a 2000kv motor rated up to 3000w to power this compressor, running on a 6 cell lipo battery so the impeller speed was around 44,000 RPM. The current draw was about 120 amps making this a very power-hungry machine.
printing instructions:
impeller: 1-2mm wall out of high temp. filament, 40-60% infill with 1-2mm top/bottom thickness.
diffuser shroud: 1.2mm wall out of high temp, filament, 20% infill with 1mm top/bottom thickness.
intake shroud: 2mm wall out of high temp. filament, 20% infill with 2mm top/ bottom thickness.
pyroflask adapter and nosecone: 1mm wall, high temp. filament with 1mm top/bottom thickness.
motor plate: DO NOT 3D PRINT! get cut or machined out of 3-5mm aluminum as it will be exposed to the most extreme temperatures and will help dissipate motor heat.
Assembly:
First print all parts according to the printing instructions and in post-processing clean them up as well as you can. Paint is optional but can help seal any pores in FDM parts. Glue the intake shroud to the diffuser shroud on the side without the screw hole pattern. you are going to want to make the motor plate out of aluminum for heat resistance and you can print out the part for reference as a cutting/drilling guide. Bolt the motor to the finished metal plate and attach the impeller to the motor using a "collet prop adapter". Adjust the height of the impeller with spacers and use screws to attach it to the diffuser shroud assembly. Use screws to attach the combustor adapter and more glue to attach the nosecone but these are rather specific and are optional depending on your use
for mounting the impeller, use collet prop adapters that fit your motor and be sure that your impeller is balanced. an imbalanced impeller will cause damaging vibration that could destroy your motor and cause an explosion. Print and test at your own risk.
The impeller cannot withstand over 50,000 RPM and may explode if over sped.
License:
Creative Commons - Attribution - Share Alike