An aircraft propeller extension moves the propeller forward a specified distance to allow a compatible spinner to align with the cowling in a more aerodynamic fashion than would be possible without the extension.


We manufacture a 4 inch long propeller extension with six inch flanges for the SAE2 propeller hub such as that found on the Lycoming O-320 engine. Popular aircraft such as Van's RV, Tailwind, and many others are designed to use such an extension.

If your engine is over 160 hp, and you will be using a wood or composite propeller, we recommend that the extension have a 7 inch propeller flange for more grip area.  We do not make a 7 inch flanged extension.

Our four inch propeller extension is designed and manufactured to withstand the high torsional stress produced by up to 160 horse power engines:


  • More material is used between the flanges and the barrel for maximum strength (compared to other manufacturers extensions).

  • More material is used between the inside bore and the outside of the extension (compared to other manufacturers extensions) to make it stronger.

  • The strongest material possible considering weight, strength, and expense: 2024T351 (titanium would be expensive; if you would like a prop extension made out of titanium - we can do that).

  • No sharp corners anywhere, no stress risers.

  • The propeller bolts thread into lugs manufactured from 17-4 PH Stainless Steel.  This material has the right ductility, lack of brittleness, freedom from galling, and excellent corrosion resistance.


  • Smooth surface finish with no tool marks or chatter which could create stress risers.

  • Parallel faces to minimize vibration and run true.

  • Concentricity between all the features machined into the extension such as: bolt holes, center bore, and barrel outside diameter, etc.

  • All manufacturing is done on a precision Computer Numerical Control mill and lathe by experienced machinists.


  1. Length            4 inches​​

  2. Flange Diameters  6 inches (both sides)

  3. Engine bolts      3/8 or 7/16 or 1/2

  4. Propeller bolts   3/8 or 7/16 or 1/2

  5. Threaded lugs     installed in extension

  6. SAE               2 Standard AS-127 Hub

  7. Engine            Lycoming O-320 or O-360

  8. Prop              Wood, Composite or Metal