Turbine engine with composite airfoils

A turbine engine comprising:

• a fan;
• a turbomachine comprising a compressor section, a combustor in fluid communication with the compressor section, and a turbine section in fluid communication with the combustor;
• a speed reduction device driven by the turbine section and configured for rotating the fan;
• and
• composite airfoils comprising at least one composite fan blade and at least one composite outlet guide vane downstream from the at least one composite fan blade;
• wherein an airfoil of the composite airfoils comprises:
• a composite body extending chordwise from a body leading edge to a body trailing edge, and
• a leading edge protector having a protector leading edge different from the body leading edge, the leading edge protector receiving at least a portion of the body leading edge;
• wherein a leading length (LL) extends chordwise from the protector leading edge to an end of the leading edge protector and a chord length (CL) extends chordwise from the protector leading edge to the body trailing edge, and
• wherein the LL is related to the CL by an airfoil protection factor
• (
• APF
• )
• =
• (
• LL
• )
• (
• CL
• )
• ;
• and a first APF (APF1) for the at least one composite fan blade is greater than or equal to 0.2 and less than or equal to 0.30 (0.2≤APF1≤0.3) and a second APF (APF2) for the at least one composite outlet guide vane is greater than or equal to 0.08 and less than or equal to 0.17 (0.08≤APF2≤0.17);
• and
• wherein at least one portion of the composite body of the at least one composite fan blade or the at least one composite outlet guide vane is configured to flex or configured to break.