Which EDF Size is BEST? (70–100mm Full Test)

I tested 70mm, 80mm, 90mm, and 100mm fully 3D printed EDFs using QX and Tomcat 2600KV motors to find out what actually delivers real thrust. By comparing FDM vs. resin propellers on a fixed load-cell thrust rig, I discovered that bigger isn't always better—motor matching and print quality change everything. _____________________________________________________________________________ EDF Performance Highlights: 70mm EDF: Best efficiency (~1.35), low power consumption, ideal for lightweight efficiency. 80mm EDF: The "Goldilocks" size—best balance of stability and performance (~1040g). 90mm EDF: Peak performance jump up to 1310g (with resin prop), but pushes current to 99A. 100mm EDF: Diminishing returns—not worth it without a 6S motor setup. _____________________________________________________________________________ Test Setup & Authority: Thrust Rig: Fixed mount with load cell + real-time current/voltage monitoring. Motors: QX and Tomcat 2600KV series. _____________________________________________________________________________ Download STL Files & Tested Configurations: Access the full design library, including the specific impeller geometries and housing files used in these tests: EDF Collection : https://themechninja.com/product-cate... 70 mm EDF V2.0 : https://themechninja.com/product/70-m... 80 mm EDF V3.0 : https://themechninja.com/product/80-m... 90 mm EDF V1.0 : https://themechninja.com/product/90-m... 100 mm EDF V2.0 : https://themechninja.com/product/100-... _____________________________________________________________________________ All projects used in this video — check them out below: DIY CoreXY 3D Printer :    • DIY CoreXY 3D Printer Under $200 | PLA, PE...   F-35B Swivel Nozzle :    • How I Designed F35-B swivel nozzle ? 3D Pr...   _____________________________________________________________________________ Discover real DIY engineering at https://themechninja.com/ Subscribe to Mech Ninja for upcoming RC builds and real flight tests! TIMESTAMPS 0:00 The EDF Thrust Mystery 0:45 Testing Methodology (Real Data) 1:30 70mm EDF Performance (FDM vs Resin) 2:50 80mm EDF Performance (The Balanced Build) 3:30 90mm EDF (The Power Jump) 4:30 100mm EDF (Diminishing Returns) 5:10 Why Bigger Isn't Always Better 6:30 Final Verdict & Efficiency Breakdown 7:40 Next Steps: RC Builds & Flight Testing