3 ms·

If you failed to restart the engine and intended to glide some distance it might make sense to stop windmilling the prop since it generates a lot of drag. But i

• repiret 5y ago
  That's a fixed-pitch prop, which will generate more drag stopped than windmilling.
  • addaon 5y ago
    This is not true for any plane I've flown -- see discussion at https://aviation.stackexchange.com/questions/64394/does-a-windmilling-propeller-create-more-drag-than-a-stopped-propeller-in-an-eng https://aviation.stackexchange.com/questions/64394/does-a-wi..., although it does seem like there's some variability. Especially if the engine is still making compression, a windmilling prop is extracting at least enough energy from the free stream to keep not just the prop but the engine turning... this is a lot!
    • repiret 5y ago
      I agree that energy lost to turning the engine must come from the airstream, don't underestimate how much energy can be lost just to creating turbulence in the airstream - after all, that's why you drop like a rock if you do a slip with full flaps. And a stalled windmilling prop will generate less turbulence than a stalled stopped prop. The discussion at your link makes a good point though - the windmilling prop might not be stalled while a stopped prop certainly is stalled, and a stalled prop obviously creates less drag.
      • FabHK 5y ago
        It is surprising that there's no good data on it. Someone with a scientific mindset in a remote location who's good at restarting a stopped engine in flight should run a couple of tests.